US Pat. No. 9,151,807

CIRCUITS AND METHODS FOR GENERATING A SELF-TEST OF A MAGNETIC FIELD SENSOR

Allegro Microsystems, LLC...

1. A magnetic field sensor comprising:
a magnetic field sensing element supported by a substrate, wherein the magnetic field sensing element is configured to generate
a self-test signal responsive to a pulsing self-test magnetic field during one or more self-test time periods;

a self-test circuit supported by the substrate, the self-test circuit comprising:
a self test current conductor proximate to the magnetic field sensing element, the self-test current conductor for carrying
a self-test current to generate the self-test magnetic field;

a processing circuit coupled to receive a signal representative of the self-test signal; and
a diagnostic request processor configured to control the self-test current to be on or off in response to a diagnostic input
signal received by the diagnostic request processor or to be indicative of a self-test during one or more time periods in
response to a control signal generated by the diagnostic request processor.

US Pat. No. 9,538,601

METHOD AND APPARATUS FOR DRIVING LOADS USING A DC-DC CONVERTER

ALLEGRO MICROSYSTEMS, LLC...

1. A driver circuit for driving one or more loads in a controlled manner, the driver circuit comprising: a multi-mode controller
to control operation of the driver circuit, the multi-mode controller being capable of operating the driver circuit in a first
mode or a second mode based on a parameter value, wherein operation under the first mode includes using a DC-DC converter
to adjust a drive signal applied to the one or more loads in response to a DC-DC converter enable signal and operation under
the second mode includes using bypass switching to adjust the drive signal applied to the one or more loads, wherein bypass
switching includes controllably shunting drive current to a reference node in a manner that bypasses the one or more loads;
at least one node for coupling to the one or more loads during driver operation; a bypass switch coupled to the at least one
node for use in bypass switching, the bypass switch having an input to receive a switching control signal; and a bypass controller
coupled to the input of the bypass switch, the bypass controller to generate the switching control signal for the bypass switch
if the driver circuit is in the second mode; wherein the bypass controller includes an enable input for use in enabling and
disabling the bypass controller, wherein the multi-mode controller is configured to disable the bypass controller if the driver
circuit is in the first mode.

US Pat. No. 9,291,876

SYSTEM AND METHOD FOR CONTROLLING A MOTOR

Allegro Microsystems, LLC...

1. A system for controlling a camera motor comprising:
a motor driver circuit for driving the camera motor, wherein the motor driver circuit is capable of changing operation of
the motor based on parameters applied to the motor driver circuit;

a filter;
a memory containing a plurality of sets of parameters, each set of parameters comprising parameters for controlling the camera
motor and parameters for controlling a transfer function of the filter, wherein each set of parameters is associated with
a respective mode of camera operation and, when programmed into the motor driver circuit and filter, causes the motor driver
circuit to drive the camera motor and the filter to operate according to the respective mode of camera operation;

a control logic module configured to choose which of the plurality of sets of parameters to apply to driving the motor and
to apply to the filter, and to generate a signal indicating which set of parameters to apply; and

a motor control module configured to receive the signal from the control logic module, apply the chosen set of parameters
to the motor driver circuit for driving the camera motor and to the filter for controlling the transfer function of the filter,
and command the motor driver circuit to drive the motor in accordance with the applied set of parameters.

US Pat. No. 9,088,233

SYSTEMS AND METHODS FOR REDUCTION OF MOTOR JITTER WHILE DRIVING AN ELECTRIC MOTOR

Allegro Microsystems, LLC...

1. A method of driving a motor comprising:
generating a drive signal to a motor for controlling power to the motor;
generating a control signal to control a frequency of the drive signal;
monitoring a speed of the motor;
adjusting the control signal, based on the speed of the motor, to set the frequency of the drive signal to a value associated
with a duration of a phase of the motor, so as to reduce the occurrence of an incomplete pulse on the drive signal; and

generating pulses on the drive signal by toggling the drive signal when the control signal crosses a threshold.

US Pat. No. 9,368,486

DIRECT CONNECTED SILICON CONTROLLED RECTIFIER (SCR) HAVING INTERNAL TRIGGER

Allegro Microsystems, LLC...

1. A direct connected silicon control rectifier (DCSCR), comprising:
a substrate having a semiconductor surface;
at least one n-well;
a parasitic PNP bipolar transistor and parasitic NPN bipolar transistor formed in the semiconductor surface, the parasitic
PNP bipolar transistor comprising a p+ emitter, an n-base and a p-collector;

a parasitic NPN bipolar transistor formed in the semiconductor surface, the parasitic NPN bipolar comprising an n+ emitter,
a p-base and an n-collector; and

an electrically conductive line connecting an n+ contact of the n-base to a p+ contact of the p-base so that the n-base and
the p-base are shorted,

wherein the semiconductor surface is p-type and provides the p-base, and
wherein the n-well provides the n-base.

US Pat. No. 9,172,320

ELECTRONIC CIRCUIT AND METHOD FOR SYNCHRONIZING ELECTRIC MOTOR DRIVE SIGNALS BETWEEN A START-UP MODE OF OPERATION AND A NORMAL MODE OF OPERATION

Allegro Microsystems, LLC...

8. A motor control circuit for driving a multi-phase motor having a plurality of motor windings, the motor control circuit
configured to:
generate a plurality of drive signals comprising determined start-up signal characteristics to start the multi-phase motor
spinning, wherein the determined start-up signal characteristics of the plurality of drive signals comprise a ramped start-up
of the electric motor during a ramp-up time period during a start-up mode of operation, wherein the plurality of drive signals
results in a corresponding plurality of sinusoidal current signals carried by the plurality of motor windings, and wherein
the plurality of drive signals are generated such that, at an end of the ramp-up time period, a last one of the plurality
of cycles of the sinusoidal current signal ends at a zero current;

stop the plurality of drive signals for a coasting time period following the end of the ramp-up time period;
detect a back EMF signal indicative of a zero back EMF voltage on the selected one of the plurality of motor windings while
the plurality of drive signals are stopped, the detected back EMF signal indicative of an end of the coasting time period;
and

drive the plurality of motor windings with the plurality of sinusoidal current signals in a normal mode of operation in response
to the detecting.

US Pat. No. 9,383,425

METHODS AND APPARATUS FOR A CURRENT SENSOR HAVING FAULT DETECTION AND SELF TEST FUNCTIONALITY

Allegro Microsystems, LLC...

1. An integrated circuit, comprising:
a sensing element;
fault detection module coupled to the sensing element, the fault detection module including circuitry to detect and output
a fault condition and circuitry to perform self-test operation of the circuitry to detect the fault condition; and

a fault pin to output the fault condition and to receive a self-test command,
wherein the fault condition includes a magnetic field is above a first threshold and/or below a second threshold,
wherein the self-test is terminated before completion when the magnetic field is above a flux threshold, and
wherein the self-test operation is initiated only when the magnetic field is below a certain level associated with no magnetic
field present.

US Pat. No. 9,291,478

MAGNETIC FIELD SENSOR WITH IMPROVED SENSITIVITY TO MAGNETIC FIELDS

Allegro Microsystems, LLC...

1. An electronic circuit, comprising:
a power supply input node configured to receive a power supply voltage, wherein the power supply voltage has, at different
times, a range of values comprising a steady state power supply voltage value, a maximum power supply voltage value above
the steady state value, and a minimum power supply voltage value below the steady state value;

a peak voltage suppression circuit having an input node and an output node, wherein the input node of the peak voltage suppression
circuit is coupled to the power supply input node, wherein the peak voltage suppression circuit is configured to suppress
the maximum value of the power supply voltage, wherein the peak voltage suppression circuit is configured to generate a suppressed
voltage at the output node of the peak voltage suppression circuit, wherein the suppressed voltage has a maximum value below
the maximum value of the power supply voltage;

a voltage conversion circuit having an input node and an output node, wherein the input node of the voltage conversion circuit
is coupled to the output node of the peak voltage suppression circuit, wherein a converted voltage is generated at the output
node of the voltage conversion circuit, wherein, when the power supply voltage is at the minimum power supply voltage value,
the converted voltage has a minimum converted voltage value higher than the minimum power supply voltage value;

a sensing element coupled to receive a sensing element current or a sensing element voltage derived from the converted voltage,
wherein a sensitivity of the sensing element is related to the value of the converted voltage.

US Pat. No. 9,144,126

LED DRIVER HAVING PRIORITY QUEUE TO TRACK DOMINANT LED CHANNEL

Allegro Microsystems, LLC...

1. An electronic circuit for use in driving a plurality of light emitting diode (LED) channels coupled to a common voltage
node, each LED channel in the plurality of LED channels including a series-connected string of LEDs, the electronic circuit
comprising:
a control circuitry for controlling a DC-DC converter to generate a regulated voltage on the common voltage node, the control
circuitry to set a duty cycle of the DC-DC converter based on voltage requirements of a dominant LED channel;

a memory to store a priority queue that lists LED channels and tracks priorities of LED channels in the plurality of LED channels,
wherein a highest priority LED channel in the priority queue represents the dominant LED channel; and

a queue manager to continually update the priority queue based on operating conditions associated with the plurality of LED
channels, wherein the queue manager is configured to move an LED channel from a lower priority in the priority queue to the
highest priority in the priority queue if the queue manager determines that the LED channel requires an increase in voltage
on the common voltage node.

US Pat. No. 9,099,638

VERTICAL HALL EFFECT ELEMENT WITH STRUCTURES TO IMPROVE SENSITIVITY

Allegro Microsystems, LLC...

1. A Hall Effect element disposed over a substrate, the Hall Effect element comprising:
an N-type epitaxial layer disposed over the substrate;
a plurality of pickups implanted and diffused into the epitaxial layer, adjacent pairs of the plurality of pickups separated
by separation regions, each one of the plurality of pickups comprising a respective N-plus type diffusion;

a plurality of Light-N regions implanted and diffused into the epitaxial layer, each one of the plurality of Light-N regions
disposed and a respective one of the plurality of pickups, wherein the Hall Effect element is configured to generate a Hall
voltage between at least one pair of the plurality of pickups, wherein the Hall voltage is most responsive to a magnetic field
directed parallel to a major surface of the substrate;

a Light-P region implanted and diffused into the epitaxial layer, wherein the Light-P region extends into the separation regions;
a P-type buried layer region disposed under the epitaxial layer, implanted and diffused into the substrate, and surrounding
the plurality of pickups, wherein the P-type buried layer region is diffused from the substrate into the epitaxial layer;
and

a P-well region implanted and diffused into the epitaxial layer and surrounding the plurality of pickups at an upper surface
of the epitaxial layer, wherein the P-type buried layer region and the P-well region are coupled in a direction vertical to
the substrate so as to for a harrier to electrical charges within the epitaxial layer,

wherein the Hall Effect element is configured to pass a drive current between at least two of the plurality of pickups, and
wherein a depth of the Light-P region extending into the separation regions is selected to force the drive current deeper
and more vertically into the epitaxial layer in relation to the major surface of the substrate, resulting in a more sensitive
Hall Effect element.

US Pat. No. 9,312,473

VERTICAL HALL EFFECT SENSOR

Allegro Microsystems, LLC...

1. A vertical Hall effect sensor comprising:
a semiconductor wafer having a first conductivity type;
a plurality of semiconductive electrodes disposed on the semiconductor wafer, the plurality of semiconductive electrodes having
the first conductivity type, comprising:

a source electrode;
a first sensing electrode and a second sensing electrode, arranged such that the source electrode is between the first sensing
electrode and the second sensing electrode; and

a first drain electrode and a second drain electrode, arranged such that the first sensing electrode, second sensing electrode,
and source electrode are between the first drain electrode and the second drain electrode; and

a plurality of semiconductor fingers disposed on the semiconductor wafer and interdigitated with the plurality of semiconductive
electrodes, the semiconductor fingers having a second conductivity type,

wherein the plurality of semiconductor fingers interdigitated with the plurality of semiconductive electrodes comprises a
first semiconductor finger of the plurality of semiconductor fingers disposed between the source electrode and the first sensing
electrode.

US Pat. No. 9,285,438

CIRCUITS AND METHODS FOR PROCESSING SIGNALS GENERATED BY A PLURALITY OF MAGNETIC FIELD SENSING ELEMENTS

Allegro Microsystems, LLC...

1. A method of determining a direction of a directional magnetic field, comprising:
generating a table of difference values comprising a plurality of difference values, each difference value of the plurality
of difference values computed as a respective difference between an identified respective sine value of a sinusoid, the sinusoid
having a plurality of sine values, and a ninety-degree sine value of the sinusoid taken ninety degrees apart from the identified
respective sine value, wherein one of the identified sine values is at a peak value of the sinusoid and other identified sine
values are at selected phase increments of the sinusoid;

receiving the directional magnetic field with a plurality of magnetic field sensing elements for generating a corresponding
plurality of magnetic field sensing element signal values, wherein the plurality of sine values of the sinusoid is irrespective
of the plurality of magnetic field sensing element signal values;

selecting a peak magnetic field sensing element from among the plurality of magnetic field sensing elements that generates
a largest one of the plurality of magnetic field sensing element signal values as a peak magnetic field sensing element signal
value;

selecting a ninety degree magnetic field sensing element from among the plurality of magnetic field sensing elements that
has a primary response axis about ninety degrees rotated from a direction of a primary response axis of the peak magnetic
field sensing element, the ninety degree magnetic field sensing element generating a ninety degree magnetic field sensing
element signal value;

computing a difference between the peak magnetic field sensing element signal value and the ninety degree magnetic field sensing
element signal value; and

comparing the computed difference with the table of difference values to identify the direction of the directional magnetic
field, wherein at least one of the above steps is performed by a processor.

US Pat. No. 9,172,565

SIGNALING BETWEEN MASTER AND SLAVE COMPONENTS USING A SHARED COMMUNICATION NODE OF THE MASTER COMPONENT

Allegro Microsystems, LLC...

1. A system, comprising:
a master component having a communication node; and
a plurality of slave components, each slave component having a bidirectional node, the slave components being configured to
each store data in response to a trigger signal received at the bidirectional node from the communication node,

wherein each of the slave components are further configured to communicate the stored data in a serial data signal from the
bidirectional node to the communication node in response to the trigger signal received at the bidirectional node from the
communication node,

wherein the slave components communicate the stored data in an order, and
wherein each of the slave components monitors serial data signal from the other slave components to the communication port.

US Pat. No. 9,062,990

CIRCULAR VERTICAL HALL MAGNETIC FIELD SENSING ELEMENT AND METHOD WITH A PLURALITY OF CONTINUOUS OUTPUT SIGNALS

Allegro Microsystems, LLC...

1. A method of operating a circular vertical Hall (CVH) sensing element having a plurality of vertical Hall element contacts
disposed in a circle over a common implant region in a substrate, the method comprising:
selecting a plurality of groups of vertical Hall element contacts from among the plurality of vertical Hall element contacts,
each group representative of a respective one of a plurality of vertical Hall elements, wherein the selecting comprises selecting
a first group of vertical Hall element contacts representative of a first vertical Hall element, and selecting a second group
of vertical Hall element contacts representative of a second vertical Hall element; and

driving at the same time the first and the second vertical Hall elements to provide at the same time a first vertical Hall
element output signal between two of the vertical Hall element contacts of the first group and a second vertical Hall element
output signal between two of the vertical Hall element contacts of the second group, wherein, in response to a magnetic field
having a direction along a magnetic field axis, the first and the second vertical Hall element output signals are not representative
of opposite magnetic field directions of the magnetic field relative to each other.

US Pat. No. 9,046,383

SYSTEMS AND METHODS THAT USE MAGNETIC FIELD SENSORS TO IDENTIFY POSITIONS OF A GEAR SHIFT LEVER

Allegro Microsystems, LLC...

1. A system for identifying a position of a gear shift lever, comprising:
a magnetic field sensor comprising two or more magnetic field sensing elements, the two or more magnetic field sensing elements
configured to generate two or more magnetic field signals in response to a sensed magnetic field influenced by a relative
position between the magnetic field sensor and a target, the target comprising a ferromagnetic target, the target disposed
proximate to the magnetic field sensor, wherein at least one of the magnetic field sensor or the target is configured to couple
to the gear shift lever, the gear shift lever configured to move to select from among a plurality of gears, wherein the other
one of the magnetic field sensor or the target is configured to couple to a structure stationary with respect to the gear
shift lever, wherein the target comprises:

selected characteristics such that the two or more magnetic field signals have different respective magnetic field signal
values when the gear shift lever selects different ones of the plurality of gears, wherein the magnetic field sensor further
comprises:

an electronic circuit coupled to receive the two or more magnetic field signals, wherein positions of the two or more magnetic
field sensing elements within the magnetic field sensor are selected as predetermined positions to result in the electronic
circuit being operable to generate an output signal indicative of selected ones of the plurality of gears selected by the
gear shift lever; and

a back-biasing magnet, the two or more magnetic field sensing elements disposed between the back-biasing magnet and the target,
the back-biasing magnet for generating the sensed magnetic field.

US Pat. No. 9,270,171

METHODS AND APPARATUS FOR DC-DC CONVERTER HAVING DITHERED SLOPE COMPENSATION

ALLEGRO MICROSYSTEMS, LLC...

1. A circuit, comprising:
a DC-DC converter comprising:
a boost converter to provide a DC voltage output from a DC input voltage, the DC output voltage configured to connect with
a first load terminal;

a feedback module configured to connect with a second load terminal;
a switching module having a switching element coupled to the boost converter; and
a control circuit coupled to the feedback module and to the switching module to generate a control signal to control operation
of the switching element for a single mode of operation of the switching element, wherein the control circuit includes a slope
generator to generate a ramp signal having a slope that varies cycle to cycle, wherein the ramp signal is initiated by a non-periodic
clock signal that varies cycle-to-cycle, such that the control signal for the switching element corresponds to the ramp signal,
wherein the switching element has a duty cycle that varies cycle to cycle and a duty cycle on-time that varies cycle to cycle.

US Pat. No. 9,285,812

SOFT START CIRCUITS AND TECHNIQUES

Allegro Microsystems, LLC...

26. A regulator control circuit for controlling a regulator switch that conducts to transfer energy from an input source to
an output at which a regulated output is provided, the regulator control circuit comprising:
a circuit configured to generate a control signal to control conduction of the switch and having first input responsive to
a soft start signal, a second input responsive to a feedback signal proportional to the regulated output, and an output at
which the control signal is provided; and

a soft start circuit generating the soft start signal, wherein the soft start circuit comprises:
a comparator coupled to the feedback signal and to the soft start signal and configured to provide a soft start level indicator
that transitions when the soft start signal is at a predetermined relationship with respect to the feedback signal;

a first circuit configured to ramp the soft start signal in a first direction until the soft start level indicator transitions;
and

a second circuit configured to ramp the soft start signal in a second, opposing direction for a predetermined period of time
after the soft start level indicator transitions.

US Pat. No. 9,170,128

MOTION SENSOR, METHOD, AND COMPUTER-READABLE STORAGE MEDIUM PROVIDING A MOTION SENSOR WITH A VIBRATION PROCESSOR TO SET A STATE OF A FLAG IN RESPONSE TO SELECTED ONES OF A PLURALITY OF TEST RESULTS BEING INDICATIVE OF A PASSING CO

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a plurality of magnetic field sensing elements configured to generate at least one magnetic field signal indicative of a magnetic
field associated with an object; and

a first state processor, the first state processor coupled to receive a signal representative of a first one of the at least
one magnetic field signal, wherein the first state processor comprises:

a first state logic module configured to generate a first STATE_SM signal indicative of a first plurality of states associated
with the first one of the at least one magnetic field signal, wherein the first plurality of states is indicative of a respective
range of signal values of the first one of the at least one magnetic field signal, wherein the first STATE_SM signal comprises
a respective plurality of state transitions comprising respective state transition chatter, wherein the first state logic
module is further configured to generate a first two-state POSCOMP signal having first and second different state transitions
that occur when the first STATE_SM signal is representative of respective first and second states; and

a first state peak logic module coupled to receive the first STATE_SM signal and configured to generate a first STATE_PEAK
signal, wherein the first STATE_PEAK signal comprises a respective plurality of state peak transitions having respective reduced
state chatter, wherein the magnetic field sensor further comprises:

a vibration processor coupled to the first state processor, the vibration processor comprising:
a POSCOMP validation processor, wherein the POSCOMP validation processor is coupled to receive a first plurality of test results
associated with a first plurality of tests and to set a state of a POSCOMP_OK flag signal if selected ones of the first plurality
of test results is indicative of a respective passing condition, wherein the set POSCOMP_OK flag signal is indicative of the
first POSCOMP signal being valid.

US Pat. No. 9,281,769

ELECTRONIC CIRCUIT AND METHOD FOR ADJUSTING START-UP CHARACTERISTICS OF DRIVE SIGNALS APPLIED TO AN ELECTRIC MOTOR

Allegro Microsystems, LLC...

18. A motor control circuit for driving a multi-phase motor having a plurality of motor windings, the motor control circuit
comprising a start-up control module configured to:
receive, from outside of the motor control circuit, a selection signal;
identify set of parameter values from among a plurality of different sets of parameter values retained on the motor control
circuit, wherein the plurality of different sets of parameter values is indicative of a corresponding plurality of different
start-up signal characteristics of a plurality of drive signals coupled to the plurality of motor windings, wherein at least
two of the plurality of different sets of parameter values are indicative of rotation of the multi-phase motor in the same
direction, the identifying done in accordance with the selection signal; and

determine, in accordance with the identified set of parameter values, the start-up signal characteristics of the plurality
of drive signals coupled to the plurality of motor windings, wherein the determined start-up signal characteristics of the
plurality of drive signals comprise a respective ramped start-up of the electric motor during a respective ramp-up time period
during a start-up mode of operation; wherein the motor control circuit is configured to:

generate the plurality of drive signals comprising the determined start-up signal characteristics to start the multi-phase
motor spinning.

US Pat. No. 9,068,859

MAGNETIC FIELD SENSORS AND RELATED TECHNIQUES PROVIDE A SELF-TEST BY COMMUNICATING SELECTED ANALOG OR DIGITAL SAMPLES OF A PROXIMITY SIGNAL

Allegro Microsystems, LLC...

1. A method of performing a self-test associated with a magnetic field sensor, comprising:
receiving a proximity signal responsive to a proximity of a sensed object with one or more magnetic field sensing elements
disposed on a substrate; and

with a self-test module disposed on the substrate:
sampling the proximity signal, by analog sampling or digitally converting, to generate a plurality of analog samples or a
plurality of digital samples, respectively, each digital sample comprising a plurality of digital bits;

selecting samples from among the plurality of analog or digital samples; and
communicating the selected samples to outside of the magnetic field sensor.

US Pat. No. 9,354,123

SYSTEMS AND METHODS FOR PROCESSING TEMPERATURE DATA OR OTHER SIGNALS

Allegro Microsystems, LLC...

1. A method of producing a temperature signal, comprising:
producing a magnetic field signal having a frequency spectrum, wherein the magnetic field signal is responsive to a magnetic
field;

producing a temperature signal;
modulating the temperature signal to a frequency outside the frequency spectrum of the magnetic field signal resulting in
a first modulated signal;

combining the magnetic field signal with the first modulated signal to produce a combined signal.

US Pat. No. 9,318,481

ELECTROSTATIC DISCHARGE PROTECTION DEVICE

Allegro Microsystems, LLC...

1. A silicon-controller rectifier (SCR) comprising:
a first N+ region;
a first P+ region, an anode terminal of the SCR connecting to the first N+ region and the first P+ region;
a second N+ region;
a second P+ region, a cathode terminal of the SCR connecting to the second N+ region and the second P+ region;
a P+/Intrinsic/N+ (PIN) diode disposed between the first P+ region and the second N+ region, the PIN diode comprising a third
N+ region, a third P+ region and an intrinsic material disposed between the third N+ region and the third P+ region,

wherein a first distance between the third N+ region and the third P+ region controls the trigger voltage of the SCR, and
wherein a second distance corresponding to a length of each of the third P+ region and the third N+ region controls the holding
voltage of the SCR.

US Pat. No. 9,300,235

SYSTEM AND METHOD FOR SERIAL COMMUNICATION BY AN ELECTRONIC CIRCUIT

Allegro Microsystems, LLC...

1. A motor driver comprising:
a motor coil driver responsive to a motor command signal to control a motor;
a feedback circuit to provide a feedback signal representing a status of the motor;
a first terminal coupled to receive the motor command signal when the motor driver is controlling a motor;
a second terminal coupled to transmit the feedback signal when the motor driver is controlling the motor;
a motor control logic module that receives the motor command sign as an input from the first terminal, sends control signals
to the motor coil driver to drive the motor in response to the command signal, receives the feedback signal from the feedback
circuit, and generate a motor status signal representing the status of the motor as an output to the second terminal in response
to the feedback signal;

a serial data communication circuit configured to send and receive a serial data signal in accordance with a serial communication
protocol over the first and second terminals when the motor is stopped or when a voltage on the first and/or second terminals
is not pulled high or low; and

a multiplexor coupled to the motor control logic module and the serial data communication circuit to selectively couple the
second terminal feedback signal to the motor control logic module and the serial communication module in response to a determination
that the motor is stopped or a voltage on the first and/or second terminals is not pulled high or low.

US Pat. No. 9,052,349

MAGNETIC FIELD SENSOR AND METHOD USED IN A MAGNETIC FIELD SENSOR THAT ADJUSTS A SENSITIVITY AND/OR AN OFFSET OVER TEMPERATURE

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a magnetic field sensing element configured to generate a magnetic field signal;
a gain adjustable analog circuit coupled to receive a signal representative of the magnetic field signal, coupled to receive
a gain control signal, and configured to generate a gain adjusted signal having a gain responsive to the gain control signal;

a coefficient table memory configured to receive and store a plurality of gain correction coefficients, wherein pairs of the
plurality of gain correction coefficients are associated with boundaries of respective temperature segments, each temperature
segment bounded by a pair of temperatures, wherein temperature boundaries of the temperature segments are unequally spaced;

a temperature sensor configured to generate a temperature signal representative of a temperature; and
a segment processor coupled to receive a signal representative of the temperature signal, configured to identify a temperature
segment in which the temperature represented by the temperature signal is lies, coupled to receive a pair of gain correction
coefficients associated with the identified temperature segment, and configured to interpolate between the pair of gain correction
coefficients in accordance with the temperature signal to generate an interpolated gain correction value, wherein the gain
control signal is related to the interpolated gain correction value.

US Pat. No. 9,299,915

METHODS AND APPARATUS FOR MAGNETIC SENSOR HAVING NON-CONDUCTIVE DIE PADDLE

ALLEGRO MICROSYSTEMS, LLC...

9. A device, comprising:
a conductive leadframe;
a non-conductive die paddle positioned in relation to the leadframe;
a die disposed on the die paddle; and
a magnetic transducer coupled to the die, wherein a cross section of the device through the magnetic transducer consists of
non-conductive materials.

US Pat. No. 9,294,084

MULTI-STAGE SLEW RATE CONTROL PROFILING FOR TRANSISTOR DRIVE APPLICATIONS

Allegro Microsystems, LLC...

1. An integrated circuit, comprising:
a transistor drive circuit to drive an input terminal of an external transistor, the transistor drive circuit having a controllable
output current;

a voltage monitor circuit to monitor a voltage across output terminals of the external transistor; and
control logic coupled to the transistor drive circuit, the control logic being configured to:
determine when the external transistor needs to transition between an off state and an on state; and
in response to a determination that the external transistor needs to transition between the off state and the on state:
control the transistor drive circuit to provide one current level to the input terminal of the external transistor for a first
portion of a transition period;

control the transistor drive circuit to provide another, different current level to the input terminal of the external transistor
for a second portion of the transition period; and

control the transistor drive circuit to switch from current drive to voltage drive in response to the voltage across the output
terminals of the external transistor satisfying a predetermined condition;

wherein the duration of the first portion of the transition period is designed to charge or discharge an input terminal of
the external transistor to a level at or before a beginning of a Miller plateau region associated with the external transistor.

US Pat. No. 9,245,547

MAGNETIC SENSOR HAVING ENHANCED LINEARIZATION

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic sensor device, comprising:
a magnetic field sensing element to generate an output signal;
a signal processing module coupled to the magnetic field sensing element, the signal processing module including a linearization
module to apply a third order Taylor expansion term to the output signal generated by the magnetic field sensing element,
wherein the Taylor expansion term applied to the output of the magnetic field sensing element Vout comprises

where K is a constant; and
an output module to receive the linearized signal from the linearization module and provide a device output signal.

US Pat. No. 9,082,957

ARRANGEMENTS FOR AN INTEGRATED SENSOR

Allegro Microsystems, LLC...

1. An integrated circuit, comprising:
a lead frame;
a base substrate having first and second opposing surfaces, wherein the base substrate is coupled to the lead frame such that
the second surface of the base substrate is above the lead frame and the first surface of the base substrate is above the
second surface of the base substrate;

a first substrate having first and second opposing surfaces, wherein the first substrate is coupled to the base substrate
such that the first surface of the first substrate is above the first surface of the base substrate and the second surface
of the first substrate is above the first surface of the first substrate;

a second substrate having first and second opposing surfaces, wherein the second substrate is coupled to the base substrate
such that the first surface of the second substrate is above the first surface of the base substrate and the second surface
of the second substrate is above the first surface of the second substrate;

an electronic component disposed on the first surface of the first substrate; and
a first magnetic field sensing element disposed on the first surface of the second substrate.

US Pat. No. 9,201,122

CIRCUITS AND METHODS USING ADJUSTABLE FEEDBACK FOR SELF-CALIBRATING OR SELF-TESTING A MAGNETIC FIELD SENSOR WITH AN ADJUSTABLE TIME CONSTANT

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a magnetic field sensing element configured to generate a magnetic field signal in response to a magnetic field;
a primary circuit path coupled to receive and to process the magnetic field signal, the primary circuit path comprising a
circuit parameter;

a clock frequency generator configured to generate a redistribution clock signal with a first redistribution clock frequency
during a first time period and with a second different redistribution clock frequency during a second time period;

a feedback circuit path coupled at both ends to the primary circuit path and forming a feedback loop, wherein the feedback
circuit path comprises:

a switched capacitor circuit coupled to receive the redistribution clock signal, the switched capacitor circuit forming an
integrator, the switched capacitor circuit comprising a selectable unity gain frequency having a first unity gain frequency
related to the first redistribution clock frequency during the first time period and having a second unity gain frequency
related to the second redistribution clock frequency during the second time period, wherein the feedback circuit path is configured
to generate an output signal coupled to calibrate the circuit parameter with first and second rates related to the first and
second unity gain frequencies.

US Pat. No. 9,140,536

CIRCUITS AND METHODS USING A FIRST CYCLE OF A SIGNAL TO GENERATE A THRESHOLD SIGNAL USED FOR COMPARING TO A SECOND LATER CYCLE OF THE SIGNAL

Allegro Microsystems, LLC...

1. A method of detecting movement of an object, comprising:
generating a magnetic field signal with at least one magnetic field sensing element, wherein the magnetic field signal is
proportional to a magnetic field associated with the object, wherein the magnetic field signal has cycles including a first
cycle occurring during a first time period and a second cycle occurring during a second time period, the first time period
occurring in time before the second time period;

generating a tracking signal that tracks at least a portion of the magnetic field signal;
using the tracking signal to generate a threshold sample in accordance with the first cycle of the magnetic field signal;
and

comparing the threshold sample generated in accordance with the first cycle of the magnetic field signal to the second cycle
of the magnetic field signal.

US Pat. No. 9,228,860

SENSOR AND METHOD OF PROVIDING A SENSOR

Allegro Microsystems, LLC...

1. A magnetic field sensor in a molding IC package, comprising:
a die;
a magnetic field sensing element in the die;
a leadframe having opposed first and second surfaces, the leadframe supporting the die on the first surface;
lead fingers to provide electrical connections to the leadframe and to the die; a first one of the lead fingers extending
from the leadframe in a single piece of material to provide an external lead of the IC package, wherein the die supporting
portion of the leadframe is formed from the single piece of material; and

a component coupled to the leadframe and coupled to a first one of the lead fingers formed from the single piece of material
such that the component is an integrated part of the IC package providing the sensor to minimize a an air gap between the
IC package and an object of interest:

wherein the leadframe includes a downset area at which the component is coupled to the leadframe, and
wherein a thickness of the leadframe in the downset area is less than a thickness of the leadframe in a non-downset area adjacent
to the downset area;

wherein the first one of the lead fingers includes the downset area to receive the component.

US Pat. No. 9,182,456

MAGNETIC FIELD SENSOR FOR SENSING ROTATION OF AN OBJECT

Allegro Microsystems, LLC...

1. A magnetic field sensor for sensing a position of a target object configured to rotate, comprising:
a semiconductor substrate;
a plurality of magnetic field sensing elements disposed on the semiconductor substrate, wherein the plurality of magnetic
field sensing elements is configured to generate a respective plurality of magnetic field sensing element output signals responsive
to a magnetic field having a direction component in an x-y plane parallel to a first major surface of the semiconductor substrate,
the x-y plane having an x-direction and a y-direction orthogonal to the x-direction;

an angle detection circuit coupled to receive a signal representative of the plurality of magnetic field sensing element output
signals, and configured to generate an x-y angle signal indicative of an angle of the direction component of the magnetic
field in the x-y plane; and

a thresholding processor coupled to receive the x-y angle signal, configured to compare a plurality of threshold values with
the x-y angle signal to generate a thresholded signal having at least two states, wherein the thresholded signal is in one
of the at least two states at some times and in another one of the at least two states at other times as the direction component
of the magnetic field rotates in the x-y plane.

US Pat. No. 9,184,012

INTEGRATED CIRCUIT FUSE AND METHOD OF FABRICATING THE INTEGRATED CIRCUIT FUSE

Allegro Microsystems, LLC...

1. A fuse disposed over a substrate of an integrated circuit, comprising:
a conductive trace in a fuse-level metal layer of the integrated circuit, wherein the conductive trace comprises a fusible
portion having a higher resistance than other portions of the conductive trace, and wherein the fusible portion comprises
a longest dimension;

a dielectric structure disposed over the fusible portion and beyond the fusible portion in a direction parallel to a major
surface of the substrate; and

a first cavity into the dielectric structure, the first cavity configured to capture debris from the fusible portion when
the fusible portion is fused, wherein the first cavity is proximate to the fusible portion and separated from the fusible
portion by a first separation wall, wherein the first cavity has a depth to at least a depth of the fuse-level metal layer
with a deeper direction being in a direction toward the substrate, wherein the entire first cavity is disposed to a first
side of the fusible portion in a direction parallel to a major surface of the substrate and perpendicular to the longest dimension
of the fusible portion such that no part of the first cavity is over the fusible portion, wherein the first separation wall
has a thickness selected to result in fracture, the fracture causing a fracture opening in the first separation wall and capture
of debris from the fusible portion within the first cavity when the fusible portion is fused.

US Pat. No. 9,164,826

METHOD AND APPARATUS TO RECOVER FROM AN ERRONEOUS LOGIC STATE IN AN ELECTRONIC SYSTEM

Allegro Microsystems, LLC...

1. An electronic sensor system for use in an environment prone to mechanical and electrical overstress conditions, comprising:
at least one sensor element to measure one or more operational parameters of the electronic sensor system;
first digital storage circuitry to store a current operational state of the electronic sensor system, wherein the current
operational state information stored in the first digital circuitry can include one or more errors caused by mechanical and
overstress conditions;

operational logic to determine a next operational state of the electronic sensor system based, at least in part, on an input
signal from the at least one sensor element;

redundancy logic to generate redundant information associated with the next operational state determined by the operational
logic;

second digital storage circuitry to store the redundant information; and
error checking logic to determine compatibility of the current operational state stored in the first digital storage circuitry
with the redundant information stored in the second digital storage circuitry to determine whether the current operational
state information includes the one or more errors, the error checking logic including correction logic to initiate corrective
action for the electronic system if the one or more errors is detected by the error checking logic.

US Pat. No. 9,151,771

APPARATUS AND METHOD FOR PROVIDING AN OUTPUT SIGNAL INDICATIVE OF A SPEED OF ROTATION AND A DIRECTION OF ROTATION OF A FERROMAGNETIC OBJECT

Allegro Microsystems, LLC...

1. A rotation detector, comprising:
a magnetic field sensor for providing an output signal proportional to a magnetic field associated with a ferromagnetic object
capable of rotating;

one or more detector circuits coupled to receive the output signal from the magnetic field sensor, each configured to detect
a rotation of the ferromagnetic object, the one or more detector circuits configured to generate a respective one or more
output signals, each output signal having respective rising and falling edges; and

an output protocol circuit coupled to receive the one or more output signals from the one or more detector circuits and configured
to generate an output signal indicative of a speed of rotation of the ferromagnetic object and also indicative of a direction
of rotation of the ferromagnetic object, wherein the output signal generated by the output protocol circuit comprises:

a plurality of pulses, each one of the plurality of pulses having a leading edge with a transition direction indicative of
the direction of rotation.

US Pat. No. 9,046,562

HYSTERESIS OFFSET CANCELLATION FOR MAGNETIC SENSORS

Allegro Microsystems, LLC...

1. A sensor for sensing an external AC magnetic field, comprising:
a magnetoresistive (MR) sensing device to generate a device voltage signal;
a feedback circuit to generate a feedback AC magnetic field to oppose the external AC magnetic field and to generate a sensed
voltage signal having an AC signal component and a DC offset component, the DC offset component related to hysteresis characteristics
of the MR sensing device, wherein the device voltage signal is responsive to a sum of the external AC magnetic field and the
feedback AC magnetic field;

circuitry, coupled to the MR sensing device, to receive the sensed voltage signal and to remove the DC offset component from
the sensed voltage signal;

wherein the circuitry comprises a DC offset determiner to determine an averaged DC offset based on the sensed voltage signal.

US Pat. No. 9,411,025

INTEGRATED CIRCUIT PACKAGE HAVING A SPLIT LEAD FRAME AND A MAGNET

Allegro Microsystems, LLC...

1. A magnetic field sensor comprising:
a lead frame having a first surface, a second opposing surface, and comprising a plurality of leads, wherein at least two
of the plurality of leads are electrically isolated from each other and wherein each of the at least two leads has an elongated
connection portion and a die attach portion;

a semiconductor die supporting a magnetic field sensing element and attached to the die attach portions of the at least two
leads adjacent to the first surface of the lead frame with a non-conductive attachment mechanism;

a separately formed ferromagnetic element disposed adjacent to the lead frame; and
a passive component coupled to the at least two leads, wherein the die attach portion of at least one of the plurality of
leads has a first portion that is separated from a second portion and wherein the magnetic field sensor further comprises
a passive component coupled between the first portion and second portion of the die attach portion.

US Pat. No. 9,322,887

MAGNETIC FIELD SENSOR WITH MAGNETORESISTANCE ELEMENTS AND CONDUCTIVE-TRACE MAGNETIC SOURCE

Allegro Microsystems, LLC...

1. A magnetic field sensor comprising:
a substrate;
a first magnetoresistive element supported by the substrate;
a second magnetoresistive element supported by the substrate and coupled in series with the first magnetoresistive element
to form a voltage node between the first and second magnetoresistive elements and at which an output voltage is provided that
changes in response to an external magnetic field; and

a magnetic source producing a local magnetic field having a strength sufficient to bias the first magnetoresistive element
to a resistive value that is substantially resistant to changing in response to the external magnetic field;

wherein the magnetic source comprises a conductive trace supported by the substrate and configured to carry a current to provide
the local magnetic field.

US Pat. No. 9,081,041

HIGH ACCURACY DIFFERENTIAL CURRENT SENSOR FOR APPLICATIONS LIKE GROUND FAULT INTERRUPTERS

Allegro Microsystems, LLC...

1. A differential current sensor comprising:
a first current conduction path having a first input terminal and a first output terminal and a second current conduction
path electrically isolated from the first current conduction path and having a second input terminal and a second output terminal;

magnetic field sensing elements including a first sensing element to sense a magnetic field associated with a first current
carried by the first current conduction path and a second sensing element to sense a magnetic field associated with a second
current carried by the second current conduction path;

circuitry, coupled to the magnetic field sensing elements, to provide an output signal; and
wherein the output signal comprises a difference signal indicative of a difference between a magnitude of the first current
and a magnitude of the second current.

US Pat. No. 9,448,288

MAGNETIC FIELD SENSOR WITH IMPROVED ACCURACY RESULTING FROM A DIGITAL POTENTIOMETER

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a plurality of magnetic field sensing elements, each one of the plurality of magnetic field sensing elements having a respective
plurality of contacts, wherein the plurality of magnetic field sensing elements is configured to generate a plurality of magnetic
field signals, each magnetic field signal responsive to a magnetic field;

a sequence switches circuit coupled to the plurality of magnetic field sensing elements, wherein the sequence switches circuit
is coupled to receive a control signal and, in response to the control signal, the sequence switches circuit is configured
to sequentially select from among the plurality of magnetic field signals to generate a sequenced output signal representative
of sequentially selected ones of the plurality of magnetic field signals;

a memory device configured to store a plurality of potentiometer control values; and
a variable potentiometer coupled to the sequence switches circuit, wherein the variable potentiometer is configured to attenuate
an offset of each one of the plurality of magnetic field signals within the sequenced output signal by using a respective
plurality of offset attenuation factors responsive to one or more of the plurality of potentiometer control values, wherein
each one of the plurality of offset attenuation factors is related to a respective error voltage of a respective one of the
plurality of magnetic field signals.

US Pat. No. 9,320,094

ELECTRONIC CIRCUITS FOR DRIVING SERIES CONNECTED LIGHT EMITTING DIODE STRINGS

Allegro Microsystems, LLC...

1. An electronic circuit for driving a plurality of series connected light emitting diode strings with a controllable DC-DC
converter, the electronic circuit comprising:
a plurality of field effect transistors (FETs), each FET having a respective drain, source, and gate, wherein each FET is
configured to pass a predetermined current from the respective drain to the respective source;

a plurality of resistors, each having respective first and second ends, each resistor coupled at the first end to a respective
source of one of the plurality of FETs forming a respective current sense node, wherein the drain of each FET or the second
end of each resistor is coupled to an end of a respective one of the plurality of series connected light emitting diode strings;

a plurality of amplifiers, each amplifier having a respective input node coupled to a respective current sense node, and each
amplifier having a respective output node coupled to a respective gate of a respective FET, wherein each one of the plurality
of amplifiers is configured to generate a respective control voltage signal at the respective output node indicative of a
control of the respective FET for the respective FET to pass the predetermined current from the respective drain to the respective
source;

a maximum select circuit having a plurality of input nodes coupled to receive the control voltage signals from the plurality
of amplifiers and having an output node, wherein the maximum select circuit is configured to select a largest one of the control
voltage signals and to generate a signal representative of the largest one of the control voltage signals at the output node;
and

an error amplifier having an input node and an output node, wherein the input node of the error amplifier is coupled to the
output node of the maximum select circuit, wherein the error amplifier is configured to generate an error signal at the output
node of the error amplifier, wherein the error amplifier comprises a transconductance amplifier, wherein the signal representative
of the largest one of the control voltage signals, at the input node of the error amplifier, comprises a voltage signal, wherein
the error amplifier is configured to generate the error signal as a current signal; wherein the electronic circuit further
comprises:

a capacitor coupled to the output node of the error amplifier to provide a loop filter for loop stability, wherein the capacitor
comprises an output capacitance of the error amplifier in parallel with an input capacitance of the controllable DC-DC converter.

US Pat. No. 9,265,104

ELECTRONIC CIRCUITS AND TECHNIQUES FOR MAINTAINING A CONSISTENT POWER DELIVERED TO A LOAD

Allegro Microsystems, LLC...

1. An electronic circuit to provide an adjustable average current through a load, the electronic circuit comprising:
a PWM input node coupled to receive a pulse width modulated (PWM) signal having first and second states with respective adjustable
time durations;

a condition detection circuit configured to identify a condition of the electronic circuit and to generate a condition signal
indicative of the condition;

a current extension circuit comprising an input node, a control node, and an output node, the input node of the current extension
circuit coupled receive the condition signal, the control node of the current extension circuit coupled to the PWM input node,
wherein the current extension circuit is configured to generate, at the output node of the current extension circuit, an extended
PWM signal having a first state and a second state, the first state of the extended PWM signal longer in time than the first
state of the PWM signal by an amount related to a value or a state of the condition signal;

a switching regulator control node; and
a switching regulator controller having an input node, an output node, and an enable node, the output node of the switching
regulator controller coupled to the switching regulator control node, the input node of the switching regulator controller
coupled to receive a feedback voltage related to the average current through the load, and the enable node of the switching
regulator controller coupled to receive the extended PWM signal, wherein the switching regulator controller does or does not
generate a switching signal at the output node of the switching regulator controller depending upon the first or the second
state, respectively, of the extended PWM signal.

US Pat. No. 9,417,295

CIRCUITS AND METHODS FOR PROCESSING SIGNALS GENERATED BY A CIRCULAR VERTICAL HALL (CVH) SENSING ELEMENT IN THE PRESENCE OF A MULTI-POLE MAGNET

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a semiconductor substrate having a first surface in an x-y plane;
a Circular Vertical Hall (CVH) sensing element comprised of a plurality of vertical Hall elements, wherein each one of the
plurality of vertical Hall elements is arranged upon a common circular implant region in the first surface of the semiconductor
substrate, wherein the plurality of vertical Hall elements is configured to generate a plurality of x-y output signals responsive
to a magnetic field having a direction component parallel to the x-y plane, wherein the CVH sensing element is configured
to generate a CVH output signal comprised of the plurality of x-y output signals, wherein the magnetic field results from
a multi-pole magnet having a plurality of north poles and a plurality of south poles, each disposed in a plane parallel to
the x-y plane, each north pole proximate to at least one south pole;

an angle sensing circuit coupled to receive the CVH output signal and configured to generate an x-y angle signal representative
of an angle of the direction component of the magnetic field as the multi-pole magnet and the CVH sensing element move relative
to each other;

a pole pair counting module coupled to receive a signal representative of the x-y angle signal and configured to generate
a count signal representative of a count of a number of the pole pairs of the multi-pole magnet that move past the CVH sensing
element; and

an angle interpolation module coupled to receive the x-y angle signal and the count signal, the angle interpolation module
configured to generate a reconstructed x-y angle signal representative of an angular position of the multi-pole magnet relative
to the CVH sensing element, the reconstructed x-y angle signal generated based upon the count signal and the x-y angle signal,
the reconstructed x-y angle signal having a higher resolution than the x-y angle signal.

US Pat. No. 9,389,060

MAGNETIC FIELD SENSOR AND RELATED TECHNIQUES THAT PROVIDE AN ANGLE ERROR CORRECTION MODULE

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a plurality of magnetic field sensing elements, wherein each one of the plurality of magnetic field sensing elements is configured
to generate a respective x-y output signal responsive to a magnetic field in an x-y plane;

an angle processing circuit coupled to receive the x-y output signals and configured to generate an uncorrected x-y angle
value representative of an angle of the magnetic field in an x-y plane, wherein the uncorrected x-y angle value comprises
a first angle error component; and

an angle error correction module coupled to the angle processing circuit and configured to generate an x-y angle error value
indicative of an error in the uncorrected x-y angle value, wherein the angle error correction module comprises an algorithm
module configured to use a sinusoidal error relationship to describe the first angel error component, sinusoidal with respect
to the angle of the magnetic field;

a sine look up table coupled to the angle error correction module and configured to store a plurality of sine values;
a coefficient table memory coupled to the angle error correction module and configured to store a plurality of correction
coefficients representative of amplitudes and phases of the sinusoidal error relationship, wherein the angle error correction
module is further configured to use a selected one of the plurality of sine values and selected ones of the plurality of correction
coefficients in the sinusoidal error relationship to determine the x-y angle error value; and

a combining module configured to combine the uncorrected x-y angle value with the x-y angle error value to generate a corrected
x-y angle value having a second angle error component smaller than the first angle error component.

US Pat. No. 9,377,285

MAGNETIC FIELD SENSOR AND RELATED TECHNIQUES THAT PROVIDE VARYING CURRENT SPINNING PHASE SEQUENCES OF A MAGNETIC FIELD SENSING ELEMENT

Allegro Microsystems, LLC...

1. A method of reducing an error in a magnetic field sensor, comprising:
providing a plurality of magnetic field sensing elements, wherein each one of the plurality of magnetic field sensing elements
is configured to generate a respective x-y output signal responsive to a magnetic field in an x-y plane;

sequentially selecting, at an element selection rate with an element selection period, from among the plurality of magnetic
field sensing elements, resulting in a plurality of repeating cycles of selected magnetic field sensing elements, each repeating
cycle sequentially selecting all of the plurality of magnetic field sensing elements, wherein the repeating cycles repeat
at a cycle repetition rate with a cycle repetition period; and

current spinning, within respective element selection periods, each selected one of the plurality of magnetic field sensing
elements, wherein the current spinning comprises generating a respective plurality of current spinning phases within the respective
element selection periods, each plurality of current spinning phases within an element selection period having a respective
phase sequence with a plurality of phases, each phase having a phase period, each phase period less than an element selection
period, wherein the sequentially selecting and the current spinning together result in a sequenced-chopped signal representative
of an angle of the magnetic field, wherein a first portion of the plurality of magnetic field sensing elements has a first
current spinning phase sequence within one of the cycle repetition periods, and a second different portion of the plurality
of magnetic field sensing elements has a second different current spinning phase sequence within the same one of the cycle
repetition periods.

US Pat. No. 9,222,990

MAGNETIC FIELD SENSORS AND RELATED TECHNIQUES THAT CAN COMMUNICATE AT LEAST ONE OF THREE OR MORE POTENTIAL CATEGORIES IN WHICH ONE OR MORE CHARACTERISTIC VALUES OF A PROXIMITY SIGNAL RESPONSIVE TO A PROXIMITY OF A SENSED OBJECT AR

Allegro Microsystems, LLC...

1. A method of performing a self-test associated with a magnetic field sensor, comprising:
generating a proximity signal responsive to a proximity of a sensed object with one or more magnetic field sensing elements;
identifying one or more characteristic values associated with the proximity signal, while the proximity signal is responding
to the proximity of the sensed object;

categorizing the one or more characteristic values into a plurality of potential categories, the plurality of potential categories
including three or more categories, wherein the plurality of potential categories is representative of a plurality of discrete
self-test states of the proximity signal, wherein one or more of the plurality of discrete self-test states occur while the
proximity signal is responding to the proximity of the sensed object; and

communicating at least one of the plurality of potential categories into which at least one of the one or more characteristic
values was categorized.

US Pat. No. 9,155,156

ELECTRONIC CIRCUITS AND TECHNIQUES FOR IMPROVING A SHORT DUTY CYCLE BEHAVIOR OF A DC-DC CONVERTER DRIVING A LOAD

Allegro Microsystems, LLC...

1. An electronic circuit to provide a regulated voltage to a load, the electronic circuit comprising:
a PWM input node coupled to receive a pulse width modulated (PWM) signal having first and second states with a variable duty
cycle;

a capacitor voltage node coupled to receive a capacitor voltage held on a capacitor, and
an on-time extension circuit comprising an input node, a control node, and an output node, the input node of the on-time extension
circuit coupled to the capacitor voltage node, the control node of the on-time extension circuit coupled to the PWM input
node, wherein the on-time extension circuit is configured to generate at the output node of the on-time extension circuit
an extended PWM signal having a first state and a second state, the first state of the extended PWM signal longer in time
than the first state of the PWM signal by an amount determined in proportion to the capacitor voltage wherein the on-time
extension circuit further comprises:

a current source:
a capacitor coupled to receive a current from the current source;
a switch, the switch comprising an input node, an output node, and a control node, the control node of the switch coupled
to the control node of the on-time extension circuit, the input node and the output node of the switch coupled to opposite
ends of the capacitor;

an offset voltage generator comprising input node and an output node, the input node of the offset voltage generator coupled
to the capacitor voltage node; and

an amplifier comprising first and second input nodes and an output node, the first input node of the amplifier coupled to
the output node of the offset voltage generator, the second input node of the amplifier coupled to a junction between the
current source and the capacitor, the output node of the amplifier coupled to the output node of the on-time extension circuit,
wherein, in response to the first state of the PWM signal, the switch is configured to discharge the capacitor, and wherein,
in response to the second state of the PWM signal, the current source is configured to charge the capacitor.

US Pat. No. 9,411,023

MAGNETIC FIELD SENSING ELEMENT COMBINING A CIRCULAR VERTICAL HALL MAGNETIC FIELD SENSING ELEMENT WITH A PLANAR HALL ELEMENT

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic field sensing element arrangement, comprising:
a semiconductor substrate having first and second parallel major surfaces parallel to an x-y plane;
a plurality of planar Hall elements arranged as a circular planar Hall (CPH) structure, wherein each one of the plurality
of planar Hall elements is arranged upon a common circular implant region in the first major surface of the semiconductor
substrate, wherein the plurality of planar Hall elements is configured to generate a plurality of z output signals responsive
to a magnetic field having a direction component in a z direction orthogonal to the x-y plane; and

a processing circuit disposed upon the semiconductor substrate and coupled to receive a signal representative of the plurality
of z output signals, wherein each one of the plurality of planar Hall elements comprises a respective group of planar Hall
element contacts, wherein the processing circuit is operable to process the plurality of planar Hall elements using a plurality
of groups of the planar Hall element contacts to generate the signal representative of the plurality of z output signals,
the processing circuit comprising a z direction component processor coupled to receive the signal representative of the plurality
of z output signals and configured to generate an intermediate signal responsive to the direction component of the magnetic
field in the z direction, wherein the intermediate signal comprises a DC signal component having a DC signal value responsive
to a magnitude of the direction component of the magnetic field in the z direction, wherein the processing circuit is operable
to generate an output signal indicative of the magnitude of the direction component of the magnetic field in the z direction
responsive to the DC signal value.

US Pat. No. 9,400,164

MAGNETIC FIELD SENSOR AND RELATED TECHNIQUES THAT PROVIDE AN ANGLE CORRECTION MODULE

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a plurality of magnetic field sensing elements, wherein each one of the plurality of magnetic field sensing elements is configured
to generate a respective x-y output signal responsive to a magnetic field in an x-y plane;

an angle processing circuit coupled to receive the x-y output signals and configured to generate an uncorrected x-y angle
value representative of an angle of the magnetic field in an x-y plane, wherein the uncorrected x-y angle value comprises
a first angle error;

a temperature sensor configured to generate a temperature signal representative of a temperature;
an angle error correction module coupled to the angle processing circuit and the temperature sensor and configured to generate,
in response to a measured magnetic field signal and the temperature signal, an x-y angle error value indicative of an error
in the uncorrected x-y angle value and comprising a ratio of a nominal magnetic field strength to a measured magnetic field
strength;

a coefficient table configured to store a plurality of correction coefficients for use by the angle error correction module,
wherein the plurality of correction coefficients comprises a plurality of magnitudes and phases of one or more harmonics of
the first angle error; and

a combining module configured to combine the uncorrected x-y angle value with the x-y angle error value to generate a corrected
x-y angle value having a second angle error smaller than the first angle error.

US Pat. No. 9,379,708

SWITCH DRIVER CIRCUIT AND ASSOCIATED METHODS

Allegro Microsystems, LLC...

1. A driver circuit for driving a transistor having a control terminal responsive to a control signal having a slew rate during
a slew time interval, comprising:
a first driver circuit portion having a first output node coupled to the control terminal of the transistor, a first output
impedance, a first input responsive to a feedback signal, a second input responsive to a reference signal, and configured
to generate an output signal at the first output node, wherein the first driver circuit portion further comprises a differential
amplifier comprising the first input and the second input and a current mirror coupled to an output of the differential amplifier;
and

a second driver circuit portion having a second output node coupled to the control terminal of the transistor and having a
second output impedance, lower than the first output impedance, wherein the slew rate of the control signal is established
by at least one of the first driver circuit portion and the second driver circuit portion, wherein the second driver circuit
portion comprises a pre-driver circuit coupled to the first driver circuit portion and a transistor having a control terminal
and an output terminal, wherein the control terminal of the transistor is responsive to the pre-driver circuit and the output
terminal of the transistor provides the second output node, wherein the second driver circuit portion further comprises a
switch configured to be in a first position to enable the pre-driver circuit or in a second position to disable the pre-driver
circuit portion, wherein the slew rate of the control signal is established by the first driver circuit portion and the second
driver circuit portion during a first portion of the slew time interval when the switch is in the first position and wherein
the slew rate of the control signal is not established by the second driver circuit portion during a second portion of the
slew time interval, following the first portion of the slew time interval when the switch is in the second position.

US Pat. No. 9,182,250

CIRCULAR VERTICAL HALL MAGNETIC FIELD SENSING ELEMENT AND METHOD WITH A PLURALITY OF CONTINUOUS OUTPUT SIGNALS

Allegro Microsystems, LLC...

1. A method of operating a circular vertical Hall (CVH) sensing element having a plurality of vertical Hall element contacts
disposed in a circle over a common implant region in a substrate, the method comprising:
selecting a plurality of groups of vertical Hall element contacts from among the plurality of vertical Hall element contacts,
each group representative of a respective one of a plurality of vertical Hall elements, wherein the selecting comprises selecting
a first group of vertical Hall element contacts representative of a first vertical Hall element, and selecting a second group
of vertical Hall element contacts representative of a second vertical Hall element; and

driving at the same time the first and the second vertical Hall elements to provide at the same time a first vertical Hall
element output signal between two of the vertical Hall element contacts of the first group and a second vertical Hall element
output signal between two of the vertical Hall element contacts of the second group, wherein the selecting further comprises:

selecting a third group of vertical Hall element contacts representative of a third vertical Hall element from among the plurality
of vertical Hall element contacts, and wherein the driving further comprises:

driving at the same time the third vertical Hall element to provide at the same time a third vertical Hall element output
signal between two of the vertical Hall element contacts of the third group.

US Pat. No. 9,395,391

MAGNETIC FIELD SENSOR AND ASSOCIATED METHOD THAT CAN STORE A MEASURED THRESHOLD VALUE IN A MEMORY DEVICE DURING A TIME WHEN THE MAGNETIC FIELD SENSOR IS POWERED OFF

Allegro Microsystems, LLC...

15. A method of sensing a magnetic field with a magnetic field sensor, comprising:
generating a magnetic field signal responsive to the magnetic field;
generating a temperature compensated signal related to the magnetic field signal, wherein the temperature compensated signal
comprises a signal characteristic comprising least one of an amplitude or an offset;

storing, in a memory device, at a storage time, a measured threshold value related to the signal characteristic of the temperature
compensated signal;

receiving, with a comparator detector, a comparator threshold value related to the stored measured threshold value and a signal
representative of the magnetic field signal; and

comparing, with the comparator detector, the comparator threshold value with the signal representative of the magnetic field
signal to generate a comparator detector output signal.

US Pat. No. 9,337,727

CIRCUITRY TO CONTROL A SWITCHING REGULATOR

Allegro Microsystems, LLC...

1. A circuit comprising:
a switching regulator configured to provide power to a load;
a current regulator circuit coupled to the load; and
a response circuit configured to provide a voltage control signal to the switching regulator in response to voltage changes
from a signal received by the response circuit from the current regulator circuit,

wherein the voltage control signal changes non-linearly with respect to the voltage changes from the signal received by the
response circuit from the current regulator circuit.

US Pat. No. 9,329,057

GEAR TOOTH SENSOR WITH PEAK AND THRESHOLD DETECTORS

Allegro Microsystems, LLC...

1. A sensor comprising:
a magnetic field signal generating circuit comprising at least one sensing element, to generate a magnetic field signal indicative
of features of a rotational ferromagnetic object as the features pass in front of the at least one sensing element;

a threshold detector, responsive to the magnetic field signal, to generate a threshold detector output signal having transitions
associated with a comparison of the magnetic field signal to a first threshold that is a percentage of the peak-to-peak magnetic
field signal;

a peak detector, responsive to the magnetic field signal, to generate a peak detector output signal having transitions associated
with a comparison of the magnetic field signal to a second threshold that is related to a peak of the magnetic field signal;
and

a circuit, coupled to the threshold detector and peak detector, to detect the transitions of the threshold detector output
signal and peak detector output signal, and to use the detected transitions to detect an error if a sequence in which the
transitions occur deviates from an expected sequence, wherein the expected sequence is based on the first and second thresholds.

US Pat. No. 9,175,981

MOTION SENSOR, METHOD, AND COMPUTER-READABLE STORAGE MEDIUM PROVIDING A MOTION SENSOR GENERATING A SIGNAL HAVING SIGNAL STATES WITH A REDUCED AMOUNT OF STATE CHATTER

Allegro Microsystems, LLC...

1. A motion sensor, comprising:
a magnetic field sensing element configured to generate a magnetic field signal indicative of a magnetic field associated
with an object; and

a state processor coupled to receive a signal representative of the magnetic field signal, wherein the state processor is
configured to generate a STATE_SM signal indicative of a plurality of states associated with the magnetic field signal, wherein
the plurality of states is indicative of a respective range of signal values of the magnetic field signal, wherein the STATE_SM
signal comprises a plurality of state transitions, wherein the plurality of state transitions is comprising state transition
chatter, and wherein the state processor comprises:

a state peak logic module coupled to receive the STATE_SM signal and configured to generate a STATE_PEAK signal, wherein the
STATE_PEAK signal comprises a plurality of state peak transitions, wherein the plurality of state peak transitions has reduced
state transition chatter,

wherein the state peak logic module is further coupled to receive a POSCOMP_PK signal having state transitions that occur
when a state represented by the STATE_PEAK signal differs from a state represented by the STATE_SM signal by a predetermined
number of states, and wherein the state peak logic module comprises a state peak logic processor configured, if the POSCOMP_PK
signal is equal to a first state, and a state value of the STATE_SM signal is greater than a state value of the STATE_PEAK
signal, to set a state value of the STATE_PEAK signal to equal a state value of the STATE_SM signal.

US Pat. No. 9,615,413

DRIVER CIRCUIT USING DYNAMIC REGULATION AND RELATED TECHNIQUES

Allegro Microsystems, LLC...

2. A method for use in driving one or more LED loads, comprising:
regulating a voltage associated with at least one LED load; and
varying a regulated voltage value used during regulating based, at least in part, on a present dimming duty cycle associated
with the at least one LED load,

wherein varying a regulated voltage value comprises using a fixed regulated voltage value if the present dimming duty cycle
of the at least one LED load is above a first threshold value and using a variable regulated voltage value that is greater
than the fixed regulated voltage value if the present dimming duty cycle of the at least one LED load is below the first threshold
value.

US Pat. No. 9,520,871

METHODS AND APPARATUS FOR SUPPLY VOLTAGE TRANSIENT PROTECTION FOR MAINTAINING A STATE OF A SENSOR OUTPUT SIGNAL

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic sensor in an IC package, comprising: a sensing element to sense magnetic field changes in response to movement
of a target and generate a data signal corresponding to the movement of the target; a regulator voltage monitor module to
receive a regulated output voltage and transition a first hold signal to an active state when the regulated output voltage
drops below a first threshold and transition a second hold signal to an active state when the regulated output voltage drops
below a second threshold; a signal processing module to receive the first hold signal from the regulator voltage monitor module
and hold processing in a state corresponding to a time the first hold signal transitions to the active state; and an output
module for outputting a sensor data output signal output from an output pin of the IC package, wherein the sensor data output
signal corresponds to the data signal from the sensing element, the output module to receive the second hold signal from the
regulator voltage monitor module and to maintain a state of the sensor data output signal at the time the second hold signal
transitions to an active state, wherein the regulator voltage monitor is configured to generate a third hold signal for the
output module to cause the output module to transition the output pin to a high impedance state, the third hold signal to
transition to an active state when the regulator voltage drops below a third threshold lower than the first threshold.

US Pat. No. 9,354,284

MAGNETIC FIELD SENSOR CONFIGURED TO MEASURE A MAGNETIC FIELD IN A CLOSED LOOP MANNER

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic field sensor for sensing an external magnetic field, the sensor comprising:
at least one magnetic field sensing element for measuring a magnetic field produced by a first magnetic field generating source;
a current generator configured to receive one or more drive current signals at an input thereof and to generate a drive current
signal having a periodic waveform and an amplitude offset at an output thereof;

a second magnetic field generating source configured to receive the drive current signal at an input thereof and in response
thereto, provide a magnetic field to the at least one magnetic field sensing element;

a comparator configured to receive a reference voltage as a first input and an output signal from the at least one magnetic
field sensing element as a second input, and in response thereto to generate a comparator output signal having a duty cycle;
and

a compensation circuit configured to receive the comparator output signal having a duty cycle at an input thereof and to generate
an offset signal for correcting the duty cycle to a predetermined duty cycle as an output wherein a characteristic of the
offset signal is that it is proportional to a magnitude of the external magnetic field experienced by the magnetic field sensing
element when the duty cycle of the comparator output signal is substantially the same as the predetermined duty cycle.

US Pat. No. 9,379,690

DUTY CYCLE CONTROLLER

ALLEGRO MICROSYSTEMS, LLC...

1. A duty cycle controller comprising:
a first port configured to receive a voltage bias signal;
a second port configured to receive an input voltage signal;
a third port configured to provide an output signal of the duty cycle controller having a duty cycle;
a n-bit digital-to-analog converter (DAC) configured to receive the voltage bias signal and to provide a DAC output signal
to a comparator, the DAC output signal having a peak value;

the comparator configured to compare the DAC output signal from the n-bit DAC with the input voltage signal to provide a comparator
output signal; and

a latch circuit configured to:
receive a signal from the n-bit counter;
receive the comparator output signal from the comparator; and
provide the output signal,
wherein the comparator output signal is used to provide the output signal of the duty cycle controller, and
wherein the duty cycle changes with changes to the input voltage signal.

US Pat. No. 9,494,660

INTEGRATED CIRCUIT PACKAGE HAVING A SPLIT LEAD FRAME

Allegro Microsystems, LLC...

1. A magnetic field sensor comprising:
a lead frame having a first surface, a second opposing surface, and comprising a plurality of leads, wherein at least two
of the plurality of leads are electrically isolated from each other and wherein each of the at least two leads has an elongated
connection portion extending from a die attach portion;

a semiconductor die supporting a magnetic field sensing element and attached to the die attach portions of the at least two
leads;

a passive component coupled between the die attach portions of the at least two leads; and
a non-conductive adhesive between the semiconductor die and the die attach portions of the at least two leads.

US Pat. No. 9,470,765

MAGNETIC SENSOR HAVING ENHANCED LINEARIZATION BY APPLIED FIELD ANGLE ROTATION

ALLEGRO MICROSYSTEMS, LLC...

1. A device, comprising:
a first magnetoresistive magnetic field sensing element positioned with respect to a shaped conductor such that an applied
field generated by current through the shaped conductor forms an offset angle theta defined by the applied field and a field
of a first pinned layer of the first magnetoresistive magnetic field sensing element, wherein the offset angle theta is greater
than about five degrees to increase a linearity of an output of the first magnetoresistive magnetic field sensing element
for current in the shaped conductor flowing in a first direction; and

an output module to receive the output of the first magnetoresistive magnetic field sensing element and provide a device output
signal,

wherein the shaped conductor comprises an arcuate portion coupled at each end to respective linear portions, and wherein the
first magnetic field sensing element comprises a GMR having elements in a bridge configuration such that at least some of
the elements in the bridge configuration are positioned on the arcuate portion of the shaped conductor.

US Pat. No. 9,442,170

SYSTEMS AND METHODS FOR PROCESSING TEMPERATURE DATA OR OTHER SIGNALS

Allegro MicroSystems, LLC...

1. A magnetic field sensor comprising:
a circuit configured to produce a magnetic field signal having a frequency spectrum, wherein the magnetic field signal represents
a strength of an external magnetic field;

a temperature sensing circuit configured to produce a temperature signal for calibrating the magnetic field signal;
a first modulation circuit configured to modulate the temperature signal to a frequency outside the frequency spectrum of
the magnetic field signal, resulting in a first modulated signal;

a combining circuit configured to combine the magnetic field signal with the first modulated signal to produce a combined
signal; and

an output operative to provide the combined signal to a digital processing circuit.

US Pat. No. 9,425,785

SWITCHING REGULATOR WITH CONTROLLABLE SLEW RATE

Allegro Microsystems, LLC...

1. A driver circuit for driving a switching transistor having a control terminal responsive to a switching control signal,
comprising:
a plurality of driver stages, each having a control input responsive to a respective driver control signal having an on time
during which the driver stage is on and an off time during which the driver stage is off and having an output coupled to the
output of the other ones of the plurality of driver stages and to the control terminal of the switching transistor, wherein
at least one of the plurality of driver control signals has an on time that is delayed with respect to an on time of another
one of the plurality of driver control signals, wherein the switching transistor has a slew time interval that commences when
a Miller plateau of the switching transistor is reached and terminates when a source to drain voltage of the switching transistor
reaches a final voltage level and wherein at least two of the driver stages are on during the slew time interval; and

a driver control signal generator configured to generate the plurality of driver control signals, wherein each of the driver
control signals is responsive to a slew time interval indication signal indicative of commencement of the slew time interval.

US Pat. No. 9,625,535

SYSTEMS AND METHODS FOR COMPUTING A POSITION OF A MAGNETIC TARGET

Allegro MicroSystems, LLC...

1. A system comprising:
exactly three magnetic field sensing elements arranged in a non-collinear arrangement to define a plane having two dimensions,
the magnetic field sensing elements each configured to generate a respective output signal representing a respective distance
of a magnetic target from the respective magnetic field sensing element, wherein the magnetic target has a freedom of translational
movement in at least the two dimensions of the plane;

a pivotal member coupled to the magnetic target, wherein the magnetic target is fixedly attached to the pivotal member and
does not move relative to the pivotal member, the pivotal member positioned so that movement of a proximate end of the pivotal
member causes proportional translational movement of the magnetic target in the two dimensions of the plane; and

a processor circuit coupled to receive output signals from each of the sensors and configured to calculate a translational
location of the magnetic target within the two dimensions of the plane.

US Pat. No. 9,614,428

SWITCHING REGULATOR CIRCUIT ALLOWING A LOWER INPUT VOLTAGE

Allegro MicroSystems, LLC...

1. A switching voltage regulator for receiving an input voltage and for generating a regulated output voltage, the switching
regulator capable of a buck mode of operation, a boost mode of operation, and a buck-boost mode of operation, the switching
regulator comprising:
an inductor having an input terminal and an output terminal, the input terminal of the inductor coupled to an input voltage
node configured to receive the input voltage;

a first electronic switch having a first current passing terminal, a second current passing terminal, and a control terminal,
wherein the first current passing terminal is coupled to the input voltage node, the second terminal coupled to the input
terminal of the inductor, and the control terminal is coupled to receive a first control signal;

an output voltage boost circuit coupled to receive the regulated output voltage and configured to generate a boosted output
voltage related to and higher than the regulated output voltage; and

a first active electronic component powered from a voltage approximately equal to the boosted output voltage when the switching
regulator is in the boost mode of operation, wherein the first active electronic component has an output terminal at which
the first control signal is generated.

US Pat. No. 9,347,998

SYSTEM AND METHOD FOR MEASURING BATTERY VOLTAGE

Allegro Microsystems, LLC...

1. An apparatus for measuring battery voltage comprising:
a first capacitor configured to receive a charge from a battery;
a first switch configured to selectively couple the first capacitor to the battery;
a second capacitor having a first terminal coupled to a reference potential and second terminal coupled to the first capacitor
to form a node between the capacitors;

a second switch configured to allow at least a portion of the charge on the first capacitor to transfer to the second capacitor
to generate a voltage across the second capacitor that is proportional to the battery voltage; and

a measurement circuit configured to measure the generated voltage at the node between the capacitors and provide an output
signal representing the battery voltage.

US Pat. No. 9,496,708

ELECTRIC MOTOR DRIVE ISOLATION CIRCUIT

Allegro MicroSystems, LLC...

1. A motor driver circuit, comprising:
an isolation circuit, comprising:
a plurality of transistors, each one of the plurality of transistors having a respective first current passing terminal, a
respective second current passing terminal, and a respective control terminal, wherein each control terminal comprises a respective
base terminal or a respective gate terminal, wherein each respective first current passing terminal is configured to couple
to a respective one of a plurality of half bridge circuits, wherein each respective second current passing terminal is configured
to couple to a respective winding of an electric motor, and wherein each respective control terminal is coupled to a respective
one of a plurality of control signals, each control signal floating relative to a voltage of a respective winding of the electric
motor; and

a plurality of diodes, each one of the plurality of diodes having a respective anode end and a respective cathode end, wherein
each respective cathode end or each respective anode end is coupled to a respective control terminal of a respective one of
the plurality of transistors, and wherein the other one of each respective anode end or each respective cathode end is coupled
to a reference voltage source, the same reference voltage source coupled to each one of the plurality of diodes, wherein the
reference voltage source provides a continuous, uninterrupted, and fixed reference voltage coupled to each respective anode
end or each respective cathode end.

US Pat. No. 9,910,087

INTEGRATED CIRCUIT AND METHOD FOR DETECTING A STRESS CONDITION IN THE INTEGRATED CIRCUIT

Allegro Microsystems, LLC...

1. An integrated circuit comprising:
at least one first magnetic field sensing element comprising at least one first magnetoresistance element configured to provide
an output signal of the integrated circuit in response to a detected magnetic field; and

at least one second magnetic field sensing element comprising at least one second magnetoresistance element configured to
have a characteristic indicative of a stress condition associated with the at least one first magnetic field sensing element.

US Pat. No. 9,664,748

SYSTEMS AND METHODS FOR PROVIDING SIGNAL ENCODING REPRESENTATIVE OF A SIGNATURE REGION IN A TARGET

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
two or more magnetic field sensing elements responsive to a target capable of moving, the target having a signature region,
wherein the two or more magnetic field sensing elements are configured to generate at least two magnetic field signals;

at least two detector circuits coupled to the two or more magnetic field sensing elements, wherein the at least two detector
circuits are configured to generate a respective at least two detector signals, wherein each detector signal has respective
state transitions with respective rates which identify a rate of movement of the target, and wherein the state transitions
of the at least two detector signals have first and second different relative phases, wherein the first and second different
relative phases identify respective first and second different directions of movement of the target; and

an output protocol processor coupled to the at least two detector circuits and configured to generate a magnetic field sensor
output signal, wherein the magnetic field sensor output signal has a plurality of pulses with respective pulse widths, wherein
first pulses with first pulse widths with a first time duration identify that the target is moving in the first direction,
wherein second pulses with second pulse widths with a second different time duration identify that the target is moving in
the second different direction, wherein third pulses with identifiable encoding identify that the signature region is passing
by the magnetic field sensor, wherein the third pulses each comprise respective state transitions and each comprise respective
pulse widths with respective fixed predetermined time durations, wherein the fixed predetermined time durations are not affected
by a size of the signature region, and wherein the first and second pulse widths of the first and second pulses that identify
the first and second different directions do not depend upon respective duty cycles of the at least two magnetic field signals
or upon respective duty cycles of the at least two detector signals.

US Pat. No. 9,642,203

CONTROLLING DIMMING RATIO AND OUTPUT RIPPLE VOLTAGE

Allegro Microsystems, LLC...

1. An integrated circuit (IC) configured to receive an input signal comprising:
a boost switch driver configured to provide a switching operation to a boost converter to drive a string of light emitting
diodes (LEDs);

a current sink driver connected to a current source and configured to provide a current signal to the string of LEDs; and
a delay module configured to delay the current signal to the string of LEDs with respect to the input signal,
wherein a resistor and a capacitor, each electrically coupled to the IC, control the delay module delaying the current signal.

US Pat. No. 9,606,190

MAGNETIC FIELD SENSOR ARRANGEMENTS AND ASSOCIATED METHODS

Allegro Microsystems, LLC...

1. A magnetic field sensor arrangement comprising:
a magnet having two opposing major surfaces, the two opposing major surfaces disposed parallel to an x-y plane of x-y-z Cartesian
coordinates, the two opposing major surfaces separated by a magnet thickness, a line parallel to the x-y plane and bisecting
one of the two opposing major surfaces, the one of the two opposing major surfaces having at least one north magnetization
on one side of the bisecting line and having at least one south magnetization on the other side of the bisecting line; and

a magnetic field sensor comprising a magnetic field sensing element with a center and with at least one major response axis
disposed in a major response plane intersecting the magnetic field sensing element, wherein the magnetic field sensor is disposed
proximate to the magnet with the major response plane within forty-five degrees of perpendicular to the x-y plane and with
the major response axis within forty-five degrees of perpendicular to the x-y plane;

wherein the magnetic field sensing element of the magnetic field sensor is disposed a first distance in a y direction from
an edge of the magnet and a second distance in a z direction from the edge of the magnet, and wherein the first and second
distances are selected to reduce an angular error of pointing directions of sensed magnetic fields versus a rotational angle
of the magnet.

US Pat. No. 9,513,337

CIRCUITS AND METHODS FOR FAULT TESTING

Allegro Microsystems, LLC...

1. An integrated circuit sensor comprising:
an oscillator for generating a master clock signal that is used by the integrated circuit sensor both when the integrated
circuit sensor is functioning in a test mode and when the integrated circuit sensor is functioning in a normal operational
mode, wherein, when the integrated circuit sensor is functioning in a test mode, a frequency of the master clock signal is
based at least in part on an externally generated programming signal provided to the integrated circuit sensor;

a fault test clock signal generator responsive to the master clock signal and to a test trigger signal, the fault test clock
signal generator configured to generate, during test of the integrated circuit sensor when the integrated circuit sensor is
functioning in its test mode, a test clock signal derived at least in part from the master clock signal, wherein the test
clock signal comprises a launch pulse and a capture pulse used during at least a portion of delay fault testing of the integrated
circuit sensor, the launch and capture pulses having a controllable time spacing between an edge of the launch pulse and an
edge of the capture pulse, wherein different values of the controllable time spacing are usable for different fault tests,
and wherein the controllable time spacing is controlled based at least in part on information conveyed via the externally
generated programming signal; and

an output processor responsive to the master clock signal and to information provided by the integrated circuit sensor relating
to a ferromagnetic article disposed in proximity to the integrated circuit sensor when the integrated circuit sensor is functioning
in its normal operational mode, the output processor providing, a sensor output signal indicative of one or more characteristics
of the article.

US Pat. No. 9,999,107

LIGHT EMITTING DIODE DRIVER FOR DIMMING AND ON/OFF CONTROL

Allegro MicroSystems, LLC...

1. An integrated circuit (IC) comprising:a first sensor means for sensing a ring magnet;
a second sensor means for sensing the ring magnet;
a processing means for controlling current to at least one light emitting diode (LED) in response to movement and position of the ring magnet with respect to the first and second sensor means; and
a counter means for measuring pole transitions of the ring magnet, wherein the brightness of the at least one LED is related to the pole transitions.

US Pat. No. 9,817,078

METHODS AND APPARATUS FOR MAGNETIC SENSOR HAVING INTEGRATED COIL

ALLEGRO MICROSYSTEMS LLC,...

1. A magnetic field sensor, comprising:
a die;
a coil proximate the die to generate a magnetic field;
a Hall element magnetic field sensing element on said die to detect changes in the magnetic field generated by the coil as
a result of movement of a ferromagnetic target external to the magnetic field sensor;

a constant current source coupled to the coil such that alignment changes of the magnetic field generated by the coil with
respect to the magnetic sensing element caused by movement of the target are detected by the magnetic field sensing element,

wherein the movement of the ferromagnetic target to a first position causes a vector of the magnetic field generated by the
coil to align substantially perpendicularly to the magnetic field sensing element which increases the magnetic field observed
by the magnetic field sensing element, and further movement of the ferromagnetic target to a second position changes the magnetic
field observed by the magnetic field sensing element; and

a GMR magnetic sensing element positioned in relation to the coil, wherein the Hall element magnetic sensing element is configured
for a first airgap distance, and the GMR magnetic sensing element is configured for a second airgap distance, which is greater
than the first airgap distance.

US Pat. No. 9,869,566

ANGLE SENSING USING DIFFERENTIAL MAGNETIC MEASUREMENT AND A BACK BIAS MAGNET

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a back bias magnet configured to generate a DC magnetic field;
first and second magnetic field sensing elements disposed along a sensing element line and disposed proximate to at least
one ferromagnetic surface of a ferromagnetic target object, the first and second magnetic field sensing elements configured
to generate first and second electronic signals, respectively, in response to first and second sensed magnetic fields corresponding
to the DC magnetic field but influenced by the at least one ferromagnetic surface;

wherein the magnetic field sensor is operable to generate a difference signal that is a difference of amplitudes of the first
and second electronic signals, and the difference signal is indicative of a rotation measurement of an absolute relative rotation
of the ferromagnetic target object and the magnetic field sensor about a rotation axis, wherein the sensing element line is
substantially parallel to the rotation axis, wherein the at least one ferromagnetic surface of the ferromagnetic target object
comprises a helical groove disposed on the ferromagnetic target object, the helical groove configured to provide the difference
signal with respect to the absolute relative rotation.

US Pat. No. 9,866,014

ELECTRONIC DEVICE WITH SHARED EOS PROTECTION AND POWER INTERRUPTION MITIGATION

Allegro MicroSystems, LLC...

1. An electronic device comprising:
a power interruption mitigation circuit configured to provide power to the electronic device if the power for the electronic
device is interrupted;

a power input terminal to receive power for the electronic device; a power mitigation input terminal to receive power for
the power interruption mitigation circuit;

an output terminal;
a ground terminal; and
a shared electrical over-stress (EOS) protection circuit comprising a power clamp circuit having:
one terminal coupled to the power input terminal, the power mitigation input terminal, and the output terminal; and
another terminal coupled directly to the ground terminal to provide a first EOS current path from the power input terminal
to the ground terminal, a second EOS current path from the output terminal to the ground terminal, and a third EOS current
path from the power mitigation input terminal to the ground terminal;
wherein the first, second, and third EOS current paths comprise a single shared power clamp circuit.

US Pat. No. 9,719,806

MAGNETIC FIELD SENSOR FOR SENSING A MOVEMENT OF A FERROMAGNETIC TARGET OBJECT

Allegro MicroSystems, LLC...

1. A magnetic field sensor for sensing a movement of a ferromagnetic target object having ferromagnetic target object features
with a target feature width, comprising:
a substrate;
a first full bridge circuit disposed upon the substrate and proximate to the ferromagnetic target object, comprising:
a first magnetoresistance element;
a second magnetoresistance element, the first and second magnetoresistance elements proximate to each other forming a first
proximate pair;

a third magnetoresistance;
a fourth magnetoresistance element, the third and fourth magnetoresistance elements proximate to each other forming a second
proximate pair;

a first noninverting output node joining a selected two of the first, second, third and fourth magnetoresistance elements;
a first inverting output node joining a different selected two of the first, second, third and fourth magnetoresistance elements,
wherein a first differential signal is generated between the first noninverting node and the first inverting node, wherein
the magnetic field sensor further comprises:

a second full bridge circuit disposed upon the substrate and proximate to the ferromagnetic target object, comprising:
a fifth magnetoresistance element;
a sixth magnetoresistance element, the fifth and sixth magnetoresistance elements proximate to each other forming a third
proximate pair;

a seventh magnetoresistance element;
an eighth magnetoresistance element, the seventh and eighth magnetoresistance elements proximate to each other forming a fourth
proximate pair;

a second noninverting output node joining a selected two of the fifth, sixth, seventh, and eighth magnetoresistance elements;
and

a second inverting output node joining a different selected two of the fifth, sixth, seventh, and eighth magnetoresistance
elements, wherein a second differential signal is generated between the second noninverting node and the second inverting
node, wherein the magnetic field sensor further comprises:

a first combining circuit disposed upon the substrate and configured to combine the first differential signal and the second
differential signal to generate a feature signal having a largest value when a ferromagnetic target object feature is centered
with the first and second full bridge circuits; and

a second combining circuit disposed upon the substrate and configured to combine the first differential signal and the second
differential signal to generate an edge signal having a largest value when the first full bridge circuit is on one side of
an edge of a ferromagnetic target object feature and the second full bridge circuit is on the other side of the same edge.

US Pat. No. 9,664,494

MAGNETIC FIELD SENSOR WITH IMMUNITY TO EXTERNAL MAGNETIC INFLUENCES

Allegro Microsystems, LLC...

1. A magnetic field sensor comprising:
a coil driver circuit to generate an AC signal;
an AC bias coil coupled to the coil driver circuit to receive the AC signal and to generate an AC bias magnetic field modulated
by movement of a ferromagnetic target having a target profile pattern with respect to the AC bias coil;

a magnetic field signal generator comprising at least one sensing element to produce, by sensing the modulated AC bias magnetic
field, a magnetic field signal indicative of the movement of the ferromagnetic target, the magnetic field signal having a
modulated signal portion in a first frequency band based on the sensed modulated AC bias magnetic field and an unwanted signal
portion in a second frequency band based on sensing an external magnetic interference;

circuitry including a demodulator to perform a demodulation of the magnetic field signal, wherein the magnetic field signal
generator and circuitry are provided on a semiconductor die, further comprising a package that includes a lead frame coupled
to the semiconductor die and located between the semiconductor die and the AC bias coil, and further includes a mold portion
to enclose the semiconductor die, at least a portion of the lead frame and the AC bias coil together; and

wherein the demodulation results in the modulated signal portion being shifted from the first frequency band to a third frequency
band and the unwanted signal portion being shifted to the first frequency band from the second frequency band.

US Pat. No. 9,574,867

MAGNETIC FIELD SENSOR AND RELATED TECHNIQUES THAT INJECT AN ERROR CORRECTION SIGNAL INTO A SIGNAL CHANNEL TO RESULT IN REDUCED ERROR

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a plurality of magnetic field sensing elements configured to generate a respective plurality of x-y output signals, wherein
each one of the x-y output signals is responsive to a magnetic field in an x-y plane;

a sequence switches circuit coupled to receive the plurality of x-y output signals and configured to generate a sequential
signal comprised of sequential ones of the plurality of x-y output signals, wherein the sequential signal comprises a time
waveform comprising an error component;

an angle processing channel coupled to receive the sequential signal, wherein the angle processing channel comprises:
an angle processing channel output node;
an electronic filter having an input node and an output node, wherein the electronic filter is configured to generate a filtered
signal at the output node of the electronic filter, and wherein the output node of the electronic filter is coupled to the
angle processing channel output node; and

a summing circuit having first and second input nodes and an output node, wherein the first input node is coupled to receive
a signal representative of the sequential signal and the output node is coupled to the input node of the electronic filter,
wherein the magnetic field sensor further comprises:

an error correction signal generator circuit having an output node, the error correction signal generator circuit for generating
an error correction signal at the output node, wherein the output node of the error correction signal generator circuit is
coupled to the second input node of the summing circuit, wherein the error correction signal comprises a plurality of states
including a high state and a low state, wherein the electronic filter is configured to generate the filtered signal with a
corrected error component smaller than the error component of the sequential signal.

US Pat. No. 9,537,383

SWITCHING REGULATOR WITH CONTROLLABLE DEAD TIME AND QUICK START

Allegro MicroSystems, LLC...

1. A driver circuit for driving a switching transistor of a switching regulator having a low side switch and a high side switch
coupled to the low side switch at a switch node, comprising:
an adjustable delay element coupled between a control terminal of the high side switch and a control terminal of the low side
switch and having a delay; and

a dead time calibration circuit configured to calibrate a dead time between one of the low side or the high side switch turning
off and the other one of the high side switch or the low side switch turning on, comprising:

a delay comparator configured to compare a present delay between the low side switch or the high side switch turning off and
a voltage at the switch node to a past delay between the low side switch or the high side switch turning off and the voltage
at the switch node; and

a controller responsive to the comparison by the delay comparator to adjust the delay of the adjustable delay element.

US Pat. No. 9,887,653

SENSORLESS BRUSHLESS DIRECT CURRENT (BLDC) MOTOR POSITION CONTROL

Allegro MicroSystems, LLC...

1. An electronic circuit for controlling operation of a brushless direct current (DC) motor having a plurality of windings,
the electronic circuit comprising:
a gate driver for providing an associated control signal to each of one or more switching elements coupled to the electronic
circuit, the one or more switching elements controlling a voltage applied to each of the plurality of windings of the motor;

a controller to generate a speed signal based upon a received frequency demand signal and provide the speed signal to the
gate driver;

a zero crossing detector for detecting a zero crossing of a voltage applied to at least one of the windings, the zero crossing
detector configured to transition a zero crossing signal between a first logic level and a second logic level based on the
detected zero crossing;

a position estimator for estimating an angular position of the motor, the position estimator comprising a counter configured
to count in a first predetermined direction based on the first logic level of the zero crossing signal, and configured to
count in a second predetermined direction based on the second logic level of the zero crossing signal; and

an observer for determining a value of the counter after a predetermined elapsed time, the observer configured to generate
an angular position signal based, at least in part, upon the determined value of the counter, wherein the observer is configured
to generate a frequency signal based, at least in part, upon the determined value of the counter and provide the frequency
signal to the controller, wherein the controller is configured to generate the speed signal based upon the received frequency
demand signal and the frequency signal, wherein the observer is configured to receive at least one adjustment parameter, the
observer configured to generate at least one of the angular position signal and the frequency signal based upon the determined
value of the counter and the at least one adjustment parameter, and wherein the at least one adjustment parameter comprises
a frequency adjustment parameter, KI, and wherein the observer is configured to generate the frequency signal by multiplying the determined value of the counter
by the frequency adjustment parameter, added to a previous value of the frequency signal.

US Pat. No. 9,865,807

PACKAGING FOR AN ELECTRONIC DEVICE

Allegro MicroSystems, LLC...

1. A method comprising:
processing a metal substrate;
performing a first etch on a first surface of the metal substrate to form, for an integrated circuit package, secondary leads
of a lead frame and a curved component of the lead frame having two primary leads, each primary lead located at a respective
end of the curved component and being substantially flat;

performing a second etch, on a second surface of the substrate opposite the first surface, at locations on the secondary leads
and locations on the curved component to form recessed portions, at least one of the secondary leads comprising a first recessed
portion at a first end of the secondary lead and a first outside portion being substantially flat, the first outside portion
comprising corners at a second end of the secondary lead, opposite the first end, configured to contribute to solder wicking,
the curved component comprising a second recessed portion;

attaching a die to the lead frame; and
overmolding the die and a portion of the lead frame to form a housing, wherein at least one surface of a secondary lead forms
a bottom surface of the package, wherein at least one surface of the curved component forms the bottom surface of the package,
the housing and the second recessed portion of the curved component forming a locking mechanism, the first outside portion
of the at least one of the secondary leads extending away from the housing, the two primary leads extending away from the
housing.

US Pat. No. 9,841,485

MAGNETIC FIELD SENSOR HAVING CALIBRATION CIRCUITRY AND TECHNIQUES

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to and representing
an external magnetic field and to generate a reference magnetic field signal responsive to and representing a reference magnetic
field;

at least one analog-to-digital converter responsive to the measured magnetic field signal to generate a digital measured magnetic
field signal and responsive to the reference magnetic field signal to generate a digital reference magnetic field signal;
and

a calibration circuit responsive to the digital measured magnetic field signal and to the digital reference magnetic field
signal to combine the digital measured magnetic field signal and the digital reference magnetic field signal in order to generate
a calibrated magnetic field signal that represents the external magnetic field;

wherein the calibration circuit comprises a divider configured to divide the digital measured magnetic field signal by the
digital reference magnetic field signal to generate the calibrated magnetic field signal.

US Pat. No. 9,812,588

MAGNETIC FIELD SENSOR INTEGRATED CIRCUIT WITH INTEGRAL FERROMAGNETIC MATERIAL

Allegro Microsystems, LLC...

1. A magnetic field sensor comprising:
a lead frame having a first surface and a second opposing surface;
a semiconductor die having a first surface in which a magnetic field sensing element is disposed and a second opposing surface
attached to the first surface of the lead frame;

a non-conductive mold material enclosing the die and at least a portion of the lead frame; and
a ferromagnetic mold material secured to a portion of the non-conductive mold material, wherein the ferromagnetic mold material
comprises a central aperture having a surface extending from the non-conductive mold material to an outer peripheral surface
of the ferromagnetic mold material, wherein the surface of the central aperture comprises a bend at an intermediate location
such that the surface of the central aperture has a first slope from the non-conductive mold material to the bend and a second
slope different than the first slope from the bend to the outer peripheral surface of the ferromagnetic mold material.

US Pat. No. 9,644,999

MAGNETIC FIELD SENSOR AND ASSOCIATED METHOD THAT CAN ESTABLISH A MEASURED THRESHOLD VALUE AND THAT CAN STORE THE MEASURED THRESHOLD VALUE IN A MEMORY DEVICE

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a magnetic field sensing element responsive to a changing magnetic field and configured to generate a magnetic field signal
having an amplitude;

a measured threshold module configured to generate a measured threshold signal in accordance with positive peaks and negative
peaks of the magnetic field signal;

a temperature sensor configured to sense a temperature of the magnetic field sensor and configured to generate a temperature
signal in accordance with the temperature;

a temperature coefficient module configured to generate a temperature coefficient signal in accordance with the temperature
signal and the amplitude;

a memory device coupled to receive and configured to store, at each one of a plurality of storage times, a respective value
of the temperature coefficient signal and a respective value of the measured threshold signal;

a threshold module coupled to receive, at a calculation time, a stored value of the temperature coefficient signal and a stored
value of the measured threshold signal, each stored at a selected one of the plurality of storage times prior to the calculation
time, coupled to receive the temperature signal, and configured to combine the received stored value of the temperature coefficient
signal, the received stored value of the measured threshold signal, and the temperature signal to generate a calculated threshold
value; and

a comparator coupled to receive the calculated threshold value and also coupled to receive a signal representative of the
magnetic field signal, wherein the comparator is configured to compare the calculated threshold value with a signal representative
of the magnetic field signal to generate an output signal.

US Pat. No. 9,664,752

MAGNETIC FIELD SENSOR FOR DETECTING A MAGNETIC FIELD IN ANY DIRECTION ABOVE THRESHOLDS

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
first, second, and third magnetic field sensing elements having respective first, second and third maximum response axes,
the first second and third maximum response axes pointing along respective first, second, and third different coordinate axes,
wherein, in response to a magnetic field, the first, second, and third magnetic field sensing elements are operable to generate
first second, and third magnetic field signals; and

an electronic circuit coupled to receive the first, second, and third magnetic field signals, wherein the electronic circuit
comprises:

a threshold generator configured to generate first, second, and third operating point thresholds; and
a comparator circuit configured to compare signals corresponding to the first, second, and third magnetic field signals with
the first, second, and third operating point thresholds, respectively, and to generate a comparator circuit output signal,
wherein the comparator circuit output signal changes state to a first state if a respective one or more of the signals corresponding
to the first, second, and third magnetic field signals has a magnitude above a respective one of the first, second, and third
operating point thresholds.

US Pat. No. 9,823,090

MAGNETIC FIELD SENSOR FOR SENSING A MOVEMENT OF A TARGET OBJECT

Allegro MicroSystems, LLC...

1. A magnetic field sensor for sensing a movement of a ferromagnetic target object having ferromagnetic target object features
with a target feature width, comprising:
a substrate;
a first magnetoresistance element disposed upon the substrate for generating a first signal responsive to movement of the
ferromagnetic target object features;

a second magnetoresistance element disposed upon the substrate for generating a second signal responsive to movement of the
ferromagnetic target object features;

a first combining circuit disposed upon the substrate and configured to combine the first signal and the second signal to
generate a feature signal having a largest value when a ferromagnetic target object feature is centered with the first and
second magnetoresistance elements;

a second combining circuit disposed upon the substrate and configured to combine the first signal and the second signal to
generate an edge signal having a largest value when the first magnetoresistance elements is on one side of an edge of a target
feature and the second magnetoresistance element is on the other side of the same edge, wherein the feature signal and the
edge signal are analog signals; and

an electronic circuit disposed upon the substrate, coupled to receive the feature signal and the edge signal, wherein the
electronic circuit is operable to compare the edge signal with one or more threshold values to generate a first two-state
signal and operable to compare the feature signal with another one or more threshold values to generate a second two-state
signal, wherein an output signal generated by the magnetic field sensor comprises a signal encoding that identifies an alignment
of state transitions of a selected one of the first or the second two-state signal.

US Pat. No. 9,739,847

CIRCULAR VERTICAL HALL (CVH) SENSING ELEMENT WITH SIGNAL PROCESSING

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a circular vertical Hall (CVH) sensing element comprising a plurality of vertical Hall elements, each vertical Hall element
comprised of a respective group of vertical Hall element contacts selected from among a plurality of vertical Hall element
contacts, the plurality of vertical Hall element contacts arranged over a common implant region in a semiconductor substrate,
adjacent ones of the plurality of contacts at predetermined angles from each other;

a CVH output stage comprising one or more drive circuits to drive the plurality of vertical Hall elements and produce an analog
signal representing a strength of an external magnetic field as detected by the plurality of vertical Hall elements;

an analog-to-digital converter coupled to receive the analog signal and produce a digital signal;
a quadrature modulator circuit coupled to the digital signal and operable to generate a plurality of quadrature modulated
signals; and

a processor stage coupled to receive signals representative of the plurality of quadrature modulated signals and operable
to compute an estimated angle of the external magnetic field.

US Pat. No. 9,621,140

ELECTRONIC CIRCUIT FOR DRIVING AN OUTPUT CURRENT SIGNAL AND METHOD OF DRIVING THE OUTPUT CURRENT SIGNAL FROM THE ELECTRONIC CIRCUIT TO ACHIEVE AN ALTERED TRANSITION OF THE OUTPUT CURRENT SIGNAL

Allegro MicroSystems, LLC...

1. An electronic circuit, comprising:
a semiconductor substrate;
a current node disposed upon the semiconductor substrate and operable to communicate an output current signal from the electronic
circuit;

a reactance coupled to the current node; and
a current driver circuit disposed upon the semiconductor substrate, the current driver circuit coupled to the current node,
wherein the current driver circuit is operable to provide a drive current signal with a plurality of drive current values
into or out of the current node,

wherein the plurality of drive current values results in the output current signal with a first output current value and a
second different output current value,

wherein the plurality of drive current values comprise:
a first drive current value indicative of the first output current value;
a second different drive current value indicative of the second different output current value; and
at least one of:
a third different drive current value different than the second drive current value and operable to result in a first altered
transition from the first output current value to the second output current value, the third different drive current value
having a first time period that begins proximate in time to a beginning of the first altered transition from the first output
current value to the second output current value and ends prior to a beginning of the second different output current value;
or

a fourth different drive current value different than the first drive current value and operable to result in a second altered
transition from the second output current value to the first output current value, the fourth different drive current value
having a second time period that begins proximate in time to a beginning of the second altered transition from the second
output current value to the first output current value and ends prior to a beginning of the first output current value.

US Pat. No. 9,584,059

MOTOR CONTROL SYSTEM AND INTERFACE

Allegro Microsystems, LLC...

6. A method for use within a motor control system including a controller having a speed control output terminal and a speed
feedback input terminal, the motor controller to provide a pulse-width modulated (PWM) motor speed control signal at the speed
control output terminal, the method comprising:
receiving the PWM motor speed control signal from the motor controller speed control output terminal;
generating, using a digital-to-analog converter having an input terminal coupled to the controller speed control output terminal
and an output terminal, an analog speed control signal in response to the PWM motor speed control signal;

generating a speed feedback signal indicative of a rotational speed of a motor;
generating a combined signal comprising a square wave having an amplitude responsive to the analog speed control signal and
a peak-to-peak distance responsive to the speed feedback signal;

providing the combined signal to the motor controller speed feedback input terminal via a common conductor coupled to a motor
control logic circuit speed command input terminal, the controller speed feedback input terminal, the digital-to-analog converter
output terminal, and a peak detector input terminal;

extracting, using the peak detector having an input terminal and an output terminal coupled to the motor control logic circuit
speed command input terminal, the analog motor speed command signal from the combined signal; and

providing the extracted analog motor speed command signal to the motor control logic circuit to control the speed of the motor.

US Pat. No. 9,350,350

SWITCH DRIVER CIRCUIT AND ASSOCIATED METHODS

Allegro Microsystems, LLC...

1. A driver circuit for driving a transistor having a control terminal responsive to a control signal having a slew rate during
a slew time interval, comprising:
a first driver circuit portion having a first output node coupled to the control terminal of the transistor, a first output
impedance, a first input responsive to a feedback signal, a second input responsive to a reference signal, and configured
to generate an output signal at the first output node, wherein the first driver circuit portion further comprises a differential
amplifier comprising the first input and the second input and a current mirror coupled to an output of the differential amplifier;
and

a second driver circuit portion having a second output node coupled to the control terminal of the transistor and having a
second output impedance, lower than the first output impedance, wherein the slew rate of the control signal is established
by at least one of the first driver circuit portion and the second driver circuit portion, wherein the second driver circuit
portion comprises a pre-driver circuit coupled to the first driver circuit portion and a transistor having a control terminal
and an output terminal, wherein the control terminal of the transistor is responsive to the pre-driver circuit and the output
terminal of the transistor provides the second output node, wherein the second driver circuit portion further comprises a
switch configured to be in a first position to enable the pre-driver circuit or in a second position to disable the pre-driver
circuit portion, wherein the slew rate of the control signal is established by the first driver circuit portion and the second
driver circuit portion during a first portion of the slew time interval when the switch is in the first position and wherein
the slew rate of the control signal is not established by the second driver circuit portion during a second portion of the
slew time interval, following the first portion of the slew time interval when the switch is in the second position.

US Pat. No. 9,859,489

INTEGRATED CIRCUIT HAVING FIRST AND SECOND MAGNETIC FIELD SENSING ELEMENTS

Allegro MicroSystems, LLC...

1. An integrated circuit, comprising:
a first magnetic field sensing element for providing a first sensitivity to a magnetic field;
a second magnetic field sensing element for providing a selected second different sensitivity to the magnetic field; and
a circuit coupled to the first and second magnetic field sensing elements, operable to provide the integrated circuit with
a first operating range responsive to the first magnetic field sensing element and a second selected different operating range
responsive to the second magnetic field sensing element, wherein the first and second magnetic field sensing elements are
different types of magnetic field sensing elements, wherein the different types of magnetic field sensing elements are two
different types in a group of types of magnetic field sensing elements comprising a planar Hall effect element, a vertical
Hall effect element, a giant magnetoresistance (GMR) element, an anisotropic magnetoresistance (AMR) element, and a tunneling
magnetoresistance (TMR) element.

US Pat. No. 9,810,519

ARRANGEMENTS FOR MAGNETIC FIELD SENSORS THAT ACT AS TOOTH DETECTORS

Allegro MicroSystems, LLC...

1. A magnetic field sensor for sensing motion of a ferromagnetic object, comprising:
a substrate, comprising:
a first major surface, wherein a first dimension across the first major surface of the substrate defines a width dimension
of the substrate and a second dimension across the first major surface of the substrate perpendicular to the width dimension
defines a length dimension of the substrate;

first and second substrate edges at ends of the width dimension of the substrate;
a second major surface parallel to the first major surface; and
a substrate center axis perpendicular to the first and second surfaces of the substrate, wherein the magnetic field sensor
further comprises:

a magnet, comprising:
a first major surface proximate to the substrate and substantially parallel to the first major surface of the substrate, wherein
a first dimension across the first major surface of the magnet defines a width dimension of the magnet and a second dimension
across the first major surface of the magnet perpendicular to the width dimension defines a length dimension of the magnet;

a second major surface distal from the substrate and parallel to the first major surface of the magnet; and
a magnet axis perpendicular to the first and second major surfaces of the magnet and centered within the width dimension and
length dimension of the magnet, wherein the magnet axis intersects the ferromagnetic object, wherein the magnetic field sensor
further comprises:

a magnetic field sensing element disposed upon the first major surface or the second major surface of the substrate and configured
to generate a first magnetic field signal, wherein the magnetic field sensing element comprises a sensing element center axis
perpendicular to the first surface of the substrate and passing through a center of the magnetic field sensing element, wherein
the sensing element center axis is parallel to the magnet axis and parallel to the substrate center axis, wherein a first
distance between the sensing element center axis and a first end of the width dimension of the magnet is substantially smaller
than a second distance between the first end of the width dimension of the magnet and the magnet axis, wherein a location
of the magnetic field sensing element relative to the magnet is selected to achieve the magnetic field signal having a value
less than a saturation value, wherein the center of the magnetic field sensing element is disposed proximate to a first end
of the width dimension of the substrate, wherein there is no magnetic field sensing element disposed with a center proximate
to a second different end of the width dimension of the magnet or proximate to a second different end of the width dimension
of the substrate, wherein the sensing element center axis intersects a center of rotation of the ferromagnetic object, and
wherein the substrate center axis and the magnet axis are offset from the sensing element center axis.

US Pat. No. 9,733,106

MAGNETIC FIELD SENSOR TO DETECT A MAGNITUDE OF A MAGNETIC FIELD IN ANY DIRECTION

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic field sensor, comprising:
first and second magnetic field sensing elements having respective first and second maximum response axes, the first and second
maximum response axes pointing along respective first and second different coordinate axes, wherein, in response to a magnetic
field, the first and second magnetic field sensing elements are operable to generate first and second magnetic field signals;
and

an electronic circuit coupled to receive the first and the second magnetic field signals,
wherein the electronic circuit is configured to:
determine a magnitude of a vector sum of the first and the second magnetic field signals; and
provide one or more signals in response to the magnitude of the vector sum determined,
wherein the electronic circuit configured to provide one or more signals in response to the magnitude of the vector sum determined
comprises an electronic circuit configured to provide a warning signal if the vector sum of the magnetic field exceeds a threshold
value, and

wherein the threshold varies as a function of a phase of the vector sum.

US Pat. No. 9,664,497

MAGNETIC FIELD SENSOR AND METHOD FOR SENSING RELATIVE LOCATION OF THE MAGNETIC FIELD SENSOR AND A TARGET OBJECT ALONG A MOVEMENT LINE

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a magnet operable to generate a DC magnetic field; and
first and second magnetic field sensing elements operable to sense first and second influenced magnetic fields, respectively,
related to the DC magnetic field but influenced by at least one ferromagnetic surface upon a ferromagnetic target object,
wherein the first and second magnetic field sensing elements are disposed proximate to the at least one ferromagnetic surface,
wherein the first and second magnetic field sensing elements are also operable to generate corresponding first and second
electronic signals related to the first and second influenced magnetic fields, respectively, wherein a difference of amplitudes
of the first and second electronic signals is related to a relative location of the magnetic field sensor and the ferromagnetic
target object along a movement axis, wherein a change of the relative location is indicative of a relative displacement of
the magnetic field sensor and the ferromagnetic object, and wherein the difference of the amplitudes of the first and second
electronic signals is not related to a rotation of the ferromagnetic target object about a rotation axis passing through the
ferromagnetic target object.

US Pat. No. 9,621,036

CIRCUITS AND TECHNIQUES FOR IMPROVING REGULATION IN A REGULATOR HAVING MORE THAN ONE MODE OF OPERATION

Allegro Microsystems, LLC...

1. A switching regulator control circuit for controlling a switching regulator comprising at least one switch that conducts
to transfer energy from an input source to an output at which a regulated output is provided, the switching regulator control
circuit comprising:
a first control circuit to generate a first control signal to control conduction of the at least one switch during a first
mode of operation and having a first input responsive to a first reference signal, a second input responsive to a feedback
signal proportional to the regulated output, and an output at which the first control signal is provided; and

a second control circuit to generate a second control signal to control conduction of the at least one switch during a second
mode of operation and having a first input responsive to a second reference signal, a second input responsive to the feedback
signal, and an output at which the second control signal is provided; and

a regulation mode calibration circuit coupled between the first control circuit and the second control circuit for calibrating
the second reference signal in response to the first control circuit.

US Pat. No. 9,621,041

BUCK-BOOST CONVERTER CONTROL CIRCUITS AND TECHNIQUES

Allegro Microsystems, LLC...

1. A controller for a Buck-Boost converter comprising a Buck switch coupled between an input voltage and an inductor and a
Boost switch coupled to the inductor and through an output switch to an output of the converter at which an output voltage
is provided, the controller comprising:
a feedback control circuit responsive to the converter output and configured to generate a first control signal for one of
the Buck switch and the Boost switch; and

a feed forward control circuit responsive to the input voltage and configured to generate a second control signal for the
other one of the Buck switch and the Boost switch, wherein the feed forward control circuit comprises a programmable device
selected based on a predetermined level for the output voltage, wherein the feedback control circuit is configured to generate
the first control signal for the Buck switch and the feed forward control circuit is configured to generate the second control
signal for the Boost switch, and wherein a duty cycle of the Boost switch is based on the value of the input voltage, a desired
duty cycle of the Buck switch when the converter transitions between a Buck mode of operation and a Buck-Boost mode of operation,
and the predetermined level for the output voltage.

US Pat. No. 9,552,315

DETERMINING ADDRESSES OF ELECTRICAL COMPONENTS ARRANGED IN A DAISY CHAIN

ALLEGRO MICROSYSTEMS, LLC...

1. A system, comprising:
electrical components arranged in a daisy chain and comprising:
a first electrical component disposed at a first end of the daisy chain; and
a second electrical component disposed at an opposite end of the daisy chain than the first end, each of the first and second
electrical components comprising:

an input port;
an output port; and
a common port,
wherein the first electrical component is directly coupled to a master component by no more than two connections comprising
a first connection and a second connection,

wherein the input port of the first electrical component is directly coupled to one of a supply voltage port of the master
component or a ground port of the master component by the first connection and the common ports of the first and second electrical
components are coupled to the other one of the supply voltage of the master component or the ground port of the master component
by the second connection,

wherein each electrical component is configured to determine its own address, and
wherein an address of the second electrical component is determined by the second electrical component before addresses of
the other of the electrical components are determined and the addresses of the electrical components determine a position
of an electrical component with respect to the other of the electrical components in the daisy chain,

wherein the current detection circuit comprises:
a first resistor;
a second resistor;
a first current source configured to provide a threshold current to the first resistor;
a second current source coupled to the input port through a first switch and configured to provide a start current and
a comparator configured to compare the output current with the threshold current.

US Pat. No. 10,001,519

GROUND REFERENCE FAULT DETECTION IN CIRCUITS WITH MULTIPLE GROUND REFERENCES

Allegro MicroSystems, LLC...

1. An electronic circuit comprising:a first circuit coupled to a first ground node, the first ground node coupled to a first ground reference;
a second circuit coupled to a second ground node, the second ground node coupled to a second ground reference; and
a ground fault detection circuit configured to detect an open circuit between the first ground node and the first ground reference or between the second ground node and the second ground reference, the ground fault detection circuit comprising:
a minimum voltage detection circuit to determine a minimum voltage of the first and second ground nodes, the minimum voltage detection circuit comprising two input nodes coupled to the first and second ground nodes, and an output node wherein the voltage at the output node of the minimum voltage detection circuit follows a lower voltage of the two input nodes of the minimum voltage detection circuit;
a maximum voltage detection circuit to determine a maximum voltage of the first and second ground nodes, the maximum voltage detection circuit comprising two input nodes coupled to the first and second ground nodes, and an output node wherein the voltage at the output node of the maximum voltage detection circuit follows a higher voltage of the two input nodes of the maximum voltage detection circuit; and
a comparator circuit coupled to receive the voltage at the output node of the minimum voltage detection circuit, the voltage at the output node of the maximum voltage detection circuit, and a reference voltage and, if a difference between the maximum voltage and the minimum voltage exceeds the reference voltage, to provide an output indicating a ground fault was detected,
wherein the comparator circuit compares the voltage at the first and second ground nodes by comparing the voltage at the output node of the minimum voltage detection circuit to the voltage at the output node of the maximum voltage detection circuit.

US Pat. No. 9,970,996

METHODS AND APPARATUS FOR GENERATING A THRESHOLD SIGNAL IN A MAGNETIC FIELD SENSOR

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic field sensor for detecting motion of an object, comprising:one or more magnetic field sensing elements configured to generate a magnetic field signal in response to a magnetic field associated with the object;
a motion detector responsive to the magnetic field signal and to a threshold signal and configured to generate a detector output signal having edges occurring in response to a comparison of the magnetic field signal and the threshold signal and occurring at a rate corresponding to a speed of motion of the object;
a speed detector responsive to the detector output signal to generate a speed signal having a value corresponding to a duration between edges of the detector output signal; and
a threshold generator coupled to receive the speed signal from the speed detector and coupled to the motion detector and configured to generate the threshold signal comprising a threshold adjustment amount having a level related to the speed of motion of the object in response to the speed signal.

US Pat. No. 9,852,094

DEVICE CONFIGURATION USING A MAGNETIC FIELD

Allegro MicroSystems, LLC...

1. A device configured to be coupled to a shared bus, the device comprising:
a magnetic field sensing element configured to sense a magnetic field;
wherein, upon receiving a configuration command over the shared bus, the device is configured to:
determine whether a parameter of the sensed magnetic field meets predetermined criteria; and
if the parameter of the sensed magnetic field meets the predetermined criteria, the device is configured to respond to the
configuration command by applying one or more configuration settings;

otherwise, if the parameter of the sensed magnetic field does not meet the predetermined criteria, the device is configured
to ignore the configuration command.

US Pat. No. 9,817,083

MAGNETIC FIELD SENSORS AND ASSOCIATED METHODS FOR REMOVING UNDESIRABLE SPECTRAL COMPONENTS

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a magnetic field sensing element configured to generate an electronic signal in response to a magnetic field;
an N-phase modulator coupled to receive the electronic signal and configured to generate a modulated signal having a plurality
of frequency components at different frequencies, wherein the plurality of frequency components comprises a plurality of undesirable
frequency components and a desirable frequency component, wherein the desirable frequency component comprises a magnetic field
signal representative of the magnetic field;

a primary circuit path coupled to receive the modulated signal and to process the modulated signal to generate an output signal
representative of the magnetic field signal; and

a feedback circuit network coupled at both ends of the feedback circuit network to the primary circuit path and forming a
feedback loop, the feedback circuit network configured to generate a plurality of feedback signals, wherein the feedback circuit
network comprises a plurality of feedback circuits, each feedback circuit coupled at both ends to the primary circuit path,
each feedback circuit configured to generate a different respective one of the plurality of feedback signals, the primary
circuit path configured to add each different respective one of the plurality of feedback signals to the primary circuit path
to cancel a different respective one of the plurality of undesirable frequency components.

US Pat. No. 9,812,637

SPIN VALVE MAGNETORESISTANCE ELEMENT WITH IMPROVED RESPONSE TO MAGNETIC FIELDS

Allegro MicroSystems, LLC...

1. A magnetoresistance element deposited upon a substrate, comprising:
an even number of free layer structures, the even number of free layer structures comprising a first free layer structure
and a second free layer structure;

an even number of spacer layers, the even number of spacer layers comprising a first spacer layer and a second spacer layer;
an even number of pinned layer structures, the even number of pinned layer structures comprising a first pinned layer structure
and a second pinned layer structure, wherein the even number of free layer structures, the even number of spacer layers, and
the even number of pinned layer structures are disposed in a stack of layers, wherein the first spacer layer has a first thickness,
first thickness selected to result in a first selected one of an antiferromagnetic coupling or a ferromagnetic coupling between
the first pinned layer structure and the first free layer structure, and wherein the second spacer layer has a second thickness,
different than the first thickness, the second thickness selected to result in a second selected one, different than the first
selected one, of an antiferromagnetic coupling or a ferromagnetic coupling between the second pinned layer structure and the
second free layer structure; and

an odd number of pining layers comprising at least a first pinning layer, a second pinning layer, and a third pinning layer,
the first and second pinning layers magnetically coupled to the first and second pinned layer structures, respectively, wherein
annealed magnetic directions of the first and second pinning layers are parallel to each other, and wherein an annealed magnetic
direction of the third pinning layer is not in the same direction as the annealed magnetic directions of the first and second
pinning layers.

US Pat. No. 9,804,249

DUAL-PATH ANALOG TO DIGITAL CONVERTER

Allegro MicroSystems, LLC...

1. An apparatus comprising:
at least one magnetic field sensing circuit configured to generate a measured signal representing a magnetic field during
a measured time period and to generate a reference signal representing a reference magnetic field during a reference time
period; and

at least one multi-path analog-to-digital converter (ADC) comprising:
an input;
an output; and
at least one multi-path integrator circuit to integrate the measured signal during the measured time period and integrate
the reference signal during the reference time period, the multi-path integrator circuit comprising:

a first processing circuit selectively coupled between the input and the output during the measured time period to process
the measured signal and decoupled from the input and the output during the reference time period; and

a second processing circuit selectively coupled between the input and the output during the reference time period to process
the reference signal and decoupled from the input and the output during the measured time period; and

at least one shared signal processing circuit configured to process both the measured signal and the reference signal.

US Pat. No. 9,684,042

MAGNETIC FIELD SENSOR WITH IMPROVED ACCURACY AND METHOD OF OBTAINING IMPROVED ACCURACY WITH A MAGNETIC FIELD SENSOR

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a circular vertical Hall (CVH) sensing element comprising:
a plurality of vertical Hall elements, each one of the plurality of vertical hall elements comprising respective first and
second current receiving contacts, respective first and second output signal generating contacts, and a respective at least
one reference contact, wherein the at least one reference contact is positioned between the first and second current receiving
contacts, the first output signal generating contact is positioned between the at least one reference contact and the first
current receiving contact, and the second output signal generating contact is positioned between the at least one reference
contact and the second current receiving contact; wherein the plurality of vertical Hall elements is configured to generate
a plurality of magnetic field signals, each magnetic field signal responsive to a magnetic field; the magnetic field sensor
further comprising:

a sequence switches circuit coupled to the plurality of vertical Hall elements, wherein the sequences switches circuit is
operable to sequentially select from among the plurality of vertical Hall elements to generate sequenced signal steps;

a first current source sequentially coupled by the sequence switches circuit to the first current receiving contact of sequentially
selected ones of the plurality of vertical Hall elements, and operable to provide, at first sequential times, a first current
signal to the first current receiving contact of the sequentially selected ones of the plurality of vertical Hall elements;

a second current source sequentially coupled by the sequence switches circuit to the second current receiving contact of the
sequentially selected ones of the plurality of vertical Hall elements and operable to provide, at the same first sequential
times, a second current signal to the second current receiving contact of the sequentially selected ones of the plurality
of vertical Hall elements; and

an amplifier circuit coupled to receive the sequenced signal steps produced at the first and second output signal generating
contacts of the sequentially selected ones of the plurality of vertical Hall elements, and, in response to the sequenced signal
steps, the amplifier circuit is configured to generate an amplified signal representative of sequentially selected ones of
the plurality of magnetic field signals,

wherein the first current source is sequentially coupled by the sequence switches circuit to the second current receiving
contact of the sequentially selected ones of the plurality of vertical Hall elements, and operable to provide, at second sequential
times, the first current signal to the second current receiving contact of the sequentially selected ones of the plurality
of vertical Hall elements; and

wherein the second current source is sequentially coupled by the sequence switches circuit to the first current receiving
contact of the sequentially selected ones of the plurality of vertical Hall elements, and operable to provide, at the same
second sequential times, the second current signal to the first current receiving contact of the sequentially selected ones
of the plurality of vertical Hall elements.

US Pat. No. 9,605,979

MAGNETIC FIELD SENSOR WITH MAGNETORESISTANCE ELEMENTS AND CONDUCTIVE TRACE MAGNETIC SOURCE

Allegro MicroSystems, LLC...

1. A magnetic field sensor comprising:
a substrate;
a first magnetoresistive element supported by the substrate;
a second magnetoresistive element supported by the substrate and coupled in series with the first magnetoresistive element
to form a voltage node between the first and second magnetoresistive elements and at which an output voltage is provided that
changes in response to an external magnetic field; and

a magnetic source producing a local magnetic field having a strength sufficient to bias the first magnetoresistive element
to a resistive value that is substantially resistant to changing in response to the external magnetic field;

wherein the magnetic source comprises a conductive trace supported by the substrate and configured to carry a current to provide
the local magnetic field and the first magnetoresistive element is disposed atop the conductive trace.

US Pat. No. 9,935,452

CIRCUITS AND TECHNIQUES FOR SIGNALING BETWEEN DEVICES

Allegro MicroSystems, LLC...

1. A method for signaling between a controller and a driver, the method comprising:receiving, at a pin of the driver coupled to the controller, a command signal generated by the controller, wherein the command signal is configured to cause the driver to open a switch when the command signal is in a first state and to close the switch when the command signal is in a second state; and
generating, by the driver at the pin coupled to the controller, a fault signal indicating a fault condition of the switch, wherein generating the fault signal can occur substantially simultaneously with receiving the command signal, wherein the command signal being in the first state corresponds to the command signal having a voltage level above a first predetermined threshold and wherein the command signal being in the second state corresponds to the command signal having a voltage level below a second predetermined threshold and wherein the fault signal has a voltage level above the first predetermined threshold or below the second predetermined threshold.

US Pat. No. 9,910,088

METHODS AND APPARATUS FOR SENSOR DIAGNOSTICS INCLUDING PROGRAMMABLE SELF-TEST SIGNALS

ALLEGRO MICROSYSTEMS, LLC...

1. An integrated circuit, comprising:
a magnetic sensing element;
fault detection module coupled to the sensing element, the fault detection module including circuitry to detect a fault condition
and to self-test operation of the circuitry for detecting the fault condition; and

a fault pin to indicate the fault condition, wherein the fault pin comprises an input/output pin such that pulling the fault
pin to a given voltage level for a given time provides a self-test request to initiate the self-test operation, and

wherein the fault detection module includes at least one switch to cycle through connections to known voltage and ground signals
and verify expected fault and no fault signals on the fault pin for the self-test operation of the circuitry for detecting
the fault condition.

US Pat. No. 9,897,464

MAGNETIC FIELD SENSOR TO DETECT A MAGNITUDE OF A MAGNETIC FIELD IN ANY DIRECTION

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
first and second magnetic field sensing elements having respective first and second maximum response axes, the first and second
maximum response axes pointing along respective first and second different coordinate axes, wherein, in response to a magnetic
field, the first and second magnetic field sensing elements are operable to generate first and second magnetic field signals,
the first and the second magnetic field sensing elements being chopped;

a common circuit channel comprising a switched capacitor notch filter having a first notch at a frequency selected to remove
products of the chopping; and

an electronic circuit coupled to receive the first and the second magnetic field signals,
wherein the electronic circuit is configured to:
determine a magnitude of a vector sum of the first and the second magnetic field signals; and
provide one or more signals in response to the magnitude of the vector sum determined.

US Pat. No. 9,857,437

HALL EFFECT SENSING ELEMENT

Allegro Microsystems, LLC...

1. A Hall Effect sensing element comprising:
a Hall plate having a thickness less than about 100 nanometers, wherein the Hall plate is a copper oxide; and
an adhesion layer directly in contact with the Hall plate and having a thickness in a range about 0.1 nanometers to 5 nanometers.

US Pat. No. 9,852,832

MAGNETIC FIELD SENSOR AND ASSOCIATED METHOD THAT CAN SENSE A POSITION OF A MAGNET

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
an electronic circuit, comprising:
a substrate having a major surface disposed in an x-y plane;
first, second, third, and fourth magnetic field sensing elements disposed upon the major surface of the substrate and configured
to generate first, second, third and fourth respective electronic magnetic field signals, wherein each electronic magnetic
field signal is responsive to a respective magnetic field parallel to the major surface of the substrate, wherein the first
and third magnetic field sensing elements have respective first and third maximum response axes parallel to each other, directed
in opposite directions, and parallel to the major surface of the substrate, and wherein the second and fourth magnetic field
sensing elements have respective second and fourth maximum response axes parallel to each other, directed in opposite directions,
and parallel the major surface of the substrate, wherein the first and third major response axes are not parallel to the second
and fourth major response axes;

a first differential circuit coupled to the first and third magnetic field sensing elements and configured to generate a first
difference signal related to a difference between the first and third electronic magnetic field signals;

a second differential circuit coupled to the second and fourth magnetic field sensing elements and configured to generate
a second difference signal related to a difference between the second and fourth electronic magnetic field signals, wherein
the first difference signal has an amplitude related to a an x-axis projection upon the x-y plane and the second difference
signal has an amplitude related to a y-axis projection upon the x-y plane;

a direction angle processor coupled to receive signals representative of the first and second difference signals and configured
to generate least one of an x direction angle signal or a y direction angle signal, wherein the x direction angle signal is
representative of an angle relative to an x-axis in an x-y plane, and wherein the y direction angle signal is representative
of an angle relative to a y-axis in the x-y plane; and

a tilt angle processor coupled to receive signal representative of the first and second difference signals and configured
to generate a z tilt angle signal representative of an angle relative to a z-axis in x-y-z Cartesian coordinates having the
x-y plane.

US Pat. No. 9,804,234

MAGNETORESISTANCE ELEMENT WITH AN IMPROVED SEED LAYER TO PROMOTE AN IMPROVED RESPONSE TO MAGNETIC FIELDS

Allegro MicroSystems, LLC...

1. A magnetoresistance element, comprising:
a substrate;
a seed layer structure disposed over the substrate, the seed layer structure comprising:
a ferromagnetic seed layer consisting of a binary alloy of NiFe; and
a first nonmagnetic spacer layer disposed under and directly adjacent to the ferromagnetic seed layer and proximate to the
substrate, wherein the first nonmagnetic spacer layer is comprised of Ta or Ru, the magnetoresistance element further comprising:

a free layer structure disposed over the seed layer structure, wherein the ferromagnetic seed layer comprises a crystalline
anisotropy, such that the free layer structure is promoted by the seed layer structure to have magnetic domains with magnetic
fields oriented in a first direction and to reduce the number of domains with magnetic fields pointing in one or more second
different directions.

US Pat. No. 9,741,372

DOUBLE PINNED MAGNETORESISTANCE ELEMENT WITH TEMPORARY FERROMAGNETIC LAYER TO IMPROVE ANNEALING

Allegro MicroSystems, LLC...

1. A magnetoresistance element deposited upon a substrate, comprising:
a first synthetic antiferromagnet (SAF) structure, comprising:
a first ferromagnetic layer;
a second ferromagnetic layer; and
a first spacer layer between the first and second ferromagnetic layers of the first synthetic antiferromagnet (SAF) structure,
wherein the first spacer layer is comprised of a selected material with a selected thickness to allow an antiferromagnetic
coupling between the first and second ferromagnetic layers of the first synthetic antiferromagnet (SAF) structure;

a second synthetic antiferromagnet (SAF) structure, comprising:
a third ferromagnetic layer;
a fourth ferromagnetic layer; and
a second spacer layer between the third and fourth ferromagnetic layers of the second synthetic antiferromagnet (SAF) structure,
wherein the second spacer layer is comprised of a selected material with a selected thickness to allow an antiferromagnetic
coupling between the third and fourth ferromagnetic layers of the second synthetic antiferromagnet (SAF) structure;

a first antiferromagnetic pinning layer disposed proximate to and coupled to the first synthetic antiferromagnet (SAF) structure;
a second antiferromagnetic pinning layer disposed proximate to and coupled to the second synthetic antiferromagnet (SAF) structure,
such that the first and second synthetic antiferromagnet (SAF) structures are disposed between the first and second antiferromagnetic
pinning layers, wherein the first and second antiferromagnetic layers are comprised of PtMn, wherein magnetic field directions
in the first and second synthetic antiferromagnet pinning layers are annealed to be ninety degrees apart, wherein a magnetic
field direction in the first antiferromagnetic pinning layer is annealed to be parallel with the magnetic field direction
in the first synthetic antiferromagnet (SAF) structure, and wherein a magnetic field direction in the second antiferromagnetic
pinning layer is annealed to be parallel with the magnetic field direction in the second synthetic antiferromagnet (SAF) structure;

a free layer structure disposed between the first and second synthetic antiferromagnet (SAF) structures;
a first nonmagnetic layer disposed between the first synthetic antiferromagnet (SAF) structure and the free layer structure;
a second nonmagnetic layer disposed between the second synthetic antiferromagnet (SAF) structure and the free layer structure,
wherein a material of the second nonmagnetic layer is selected to allow a thickness of the second nonmagnetic layer to be
greater than 0.5 nm while allowing a desired partial pinning between the second synthetic antiferromagnet (SAF) structure
and the free layer structure; and

a temporary ferromagnetic layer disposed over and proximate to a selected one of the first antiferromagnetic pinning layer
or the second antiferromagnetic pinning layer.

US Pat. No. 9,739,846

MAGNETIC FIELD SENSORS WITH SELF TEST

Allegro MicroSystems, LLC...

1. A method comprising:
detecting, by a magnetic field sensor, a magnetic field;
driving a signal representing the magnetic field onto an output node of the magnetic field sensor;
receiving, by the magnetic field sensor, the signal on the output node;
determining if the driven signal is interrupted by an external source by comparing the received signal to the driven signal
by determining if a voltage of the output node was driven to a predetermined voltage state during transmission of the signal
representing the magnetic field;

interrupting the signal representing the magnetic field and
when the driven signal is interrupted, initiating a self-test.

US Pat. No. 9,645,220

CIRCUITS AND METHODS FOR SELF-CALIBRATING OR SELF-TESTING A MAGNETIC FIELD SENSOR USING PHASE DISCRIMINATION

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a reference magnetic field generator, wherein the reference magnetic field generator is configured to generate an alternating
current (AC) signal having a first frequency with a first phase and to generate an alternating current (AC) reference magnetic
field having the same first frequency with the same first phase;

a magnetic field sensing circuit comprising at least one magnetic field sensing element, wherein the magnetic field sensing
circuit is configured to generate a combined output signal responsive to the alternating current (AC) reference magnetic field
and also responsive to an external magnetic field at the same time, wherein the combined signal comprises, at the same time,
an alternating current (AC) reference magnetic field signal component and an external magnetic field signal component, and
wherein the at least one magnetic field sensing element is responsive to the alternating current (AC) reference magnetic field
and, at the same time, is also responsive to the external magnetic field; and

a signal processing circuit coupled to receive the combined output signal, wherein the signal processing circuit comprises
a first modulator, wherein the first modulator is configured to modulate the combined signal with a modulation signal having
the same first frequency as the alternating current (AC) signal but with a second phase different than the first phase of
the alternating current (AC) signal to generate a modulated combined signal.

US Pat. No. 9,641,070

CIRCUITS AND TECHNIQUES FOR DETECTING AN OPEN PIN CONDITION OF AN INTEGRATED CIRCUIT

Allegro Microsystems, LLC...

1. An integrated circuit, comprising:
a current source coupled to a pin of the integrated circuit;
a comparator having a first input coupled to the pin, a second input selectively coupled to a first threshold voltage or to
a second threshold voltage, and an output at which a comparator output signal is provided; and

a controller responsive to the comparator output signal, the controller having an output coupled to the current source to
provide an enable signal to the current source and the controller configured to provide an open pin signal indicative of an
open condition at the pin, wherein when the enable signal is at a first level, the first threshold voltage is coupled to the
first comparator input and the current source is enabled, and when the enable signal is at a second level, the second threshold
voltage is coupled to the first comparator input and the current source is disabled.

US Pat. No. 9,638,764

ELECTRONIC CIRCUIT FOR DRIVING A HALL EFFECT ELEMENT WITH A CURRENT COMPENSATED FOR SUBSTRATE STRESS

Allegro Microsystems, LLC...

1. An electronic circuit, comprising:
a semiconductor substrate having a surface;
epitaxial layer disposed over the surface of the semiconductor substrate, the epitaxial layer having a first surface distal
from the semiconductor substrate and a second surface proximate to the semiconductor substrate;

a planar Hall effect element, at least a portion of the planar Hall effect element disposed in the epitaxial layer; and
a current generator configured to generate a drive current that passes through the planar Hall effect element, wherein the
current generator comprises:

a first resistor for receiving a reference voltage resulting in a reference current passing through the first resistor, the
reference current related to the drive current, the first resistor disposed in the epitaxial layer, wherein a resistance of
the first resistor, the reference current, and the drive current change in accordance with changes of a stress in the semiconductor
substrate, wherein the first resistor comprises:

first and second pickups implanted upon and diffused into the first surface of the epitaxial layer; and
a first buried structure disposed under the first surface of the epitaxial layer and under the first and second pickups, wherein
the first buried structure has a density of atoms that results in a first low resistance path a first resistance lower than
a resistance of the epitaxial layer, wherein the reference current passes from the first pickup, through a first region of
the epitaxial layer, through the first buried structure, and through a second region of the epitaxial layer to the second
pickup.

US Pat. No. 9,551,762

CIRCUITS AND METHODS FOR REMOVING A GAIN OFFSET IN A MAGNETIC FIELD SENSOR

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
two or more Hall effect elements coupled together for generating a Hall effect element signal having a magnetic field component
and an offset component, the magnetic field component responsive to an external magnetic field;

a switching circuit coupled to the Hall effect element and configured to generate a chopped signal representative of a four
phase current spinning of the Hall effect element, the four phase current spinning having four phases including a first phase,
a second phase following the first phase, a third phase following the second phase, and a fourth phase following the third
phase, the four phases periodically repeating, wherein changes between the four phases occur at a phase rate;

a first modulator coupled to the chopped signal and configured to modulate a signal related to the chopped signal with a first
modulator clock signal, wherein the first modulator clock signal has a first frequency for which changes of states of the
first modulator clock signal occur at the phase rate;

a channel amplifier coupled to the first modulated signal, coupled to a gain adjustment signal, and configured to generate
an amplified signal having a gain responsive to the gain adjustment signal, wherein the gain of the channel amplifier has
a gain average component and a gain offset component;

a second modulator coupled to the amplified signal and configured to modulate a signal related to the amplified signal with
a second modulator clock signal having the same first frequency to generate a second modulated signal;

an error amplifier coupled to a calibration signal, the calibration signal representative of a measured sensitivity of at
least a portion of the magnetic field sensor in response to a calibration magnetic field, the error amplifier operable to
compare the calibration signal to a reference signal to generate a comparison signal;

a third modulator coupled to the comparison signal and configured to modulate a signal related to the comparison signal with
a third modulator clock signal having a second different frequency equal to the first frequency divided by two to generate
a third modulated signal, wherein a first state of the third modulator clock signal occurs during the second and third phase
of the four phases and a second state of the third modulator clock signal occurs during the first and fourth phases of the
four phases, wherein the gain adjustment signal received by the channel amplifier comprises the third modulated signal; and

a filter coupled to the second modulator signal and operable to generate a magnetic field sensor signal responsive to the
external magnetic field, the magnetic field sensor signal responsive the external magnetic field, the magnetic field sensor
signal having an amplitude more responsive to the gain average component than to the gain offset component.

US Pat. No. 9,529,060

MAGNETORESISTANCE ELEMENT WITH IMPROVED RESPONSE TO MAGNETIC FIELDS

Allegro MicroSystems, LLC...

1. A magnetoresistance element, comprising:
a substrate;
a first layer disposed over the substrate, the first layer comprising a seed layer;
a second layer disposed over the first layer, the second layer comprising a first antiferromagnetic pinning layer,
a third layer disposed over the second layer, the third layer comprising a first pinned layer, wherein a position of the second
layer is selected to influence a magnetization of the third layer;

a fourth layer disposed over the third layer, the fourth layer comprising a first nonmagnetic spacer layer;
a fifth layer disposed over the fourth layer, the fifth layer comprising a free layer, the free layer having a plurality of
magnetic domains, the plurality of magnetic domains comprising:

a first plurality of magnetic domains with magnetic fields pointing in a first direction; and
a second plurality of magnetic domains with magnetic fields pointing in one or more directions different than the first direction;
a sixth layer disposed over the fifth layer, the sixth layer comprising a second pinned layer, wherein the sixth layer consists
of a single ferromagnetic layer;

a seventh layer disposed over the sixth layer, the seventh layer comprising a second antiferromagnetic pinning layer, a position
of the seventh layer selected to influence a magnetization of the sixth layer, the sixth layer at a selected position relative
to the fifth layer, the selected position of the sixth layer relative of the fifth layer resulting in a selected reduction
in a quantity of magnetic domains within the second plurality of magnetic domains in the fifth layer without fully pinning
the fifth layer; and

an eighth layer disposed between the fifth layer and the sixth and seventh layers taken together, the eighth layer comprising
a second nonmagnetic spacer layer, wherein a material of the eighth layer is selected to allow a thickness of the eighth layer
to be greater than 0.5 nm while allowing a desired partial pinning between the fifth layer and the sixth layer, wherein the
first pinned layer is comprised of:

a first ferromagnetic pinned layer disposed proximate to the second layer;
a third nonmagnetic spacer layer disposed over the first ferromagnetic pinned layer; and
a second ferromagnetic pinned layer disposed over the third nonmagnetic spacer layer,
wherein magnetic field directions in the first and second pinned layers are annealed to be ninety degrees apart, and wherein
a magnetic field direction in the second pinned layer is parallel with a magnetic field direction in the second antiferromagnetic
pinning layer, and

wherein the first and second antiferromagnetic pinning layers are both comprised of PtMn.

US Pat. No. 9,958,482

SYSTEMS AND METHODS FOR A HIGH ISOLATION CURRENT SENSOR

Allegro MicroSystems, LLC...

1. A current sensor comprising:a primary conductor configured to carry a first portion of a primary current;
a semiconductor substrate having a first surface and a second opposing surface, the first surface supporting a magnetic field sensing circuit, a first insulation layer disposed over the first surface, and a conductive layer disposed over the first insulation layer, wherein the primary conductor is spaced from the semiconductor substrate such that the primary conductor and the semiconductor substrate do not vertically overlap each other; and
at least two interconnects comprising wire bonds coupled between the primary conductor and the conductive layer, wherein a second portion of the primary current flows through the conductive layer, and wherein the magnetic field sensing circuit is configured to sense the second portion of the primary current.

US Pat. No. 9,851,417

STRUCTURE AND SYSTEM FOR SIMULTANEOUS SENSING A MAGNETIC FIELD AND MECHANICAL STRESS

Allegro MicroSystems, LLC...

1. A magnetic field sensor comprising:
a substrate having a bottom surface and a top surface;
an epitaxial layer disposed over the top surface of the substrate, the epitaxial layer having a top surface and a bottom surface,
the bottom surface of the epitaxial layer proximate to and parallel to the top surface of the substrate; and

a dual Hall element, comprising:
a first planar Hall element disposed within or over the epitaxial layer, the first planar Hall element having a first plurality
of pickups with a first center between the first plurality of pickups; and

a second planar Hall element disposed within or over the epitaxial layer, the second planar Hall element having a second different
plurality of pickups with a second center between the second plurality of pickups, wherein a line intersecting the first and
second centers is perpendicular to the top surface of the epi layer,

wherein the first planar Hall element has a first sensitivity to a magnetic field and a first sensitivity to mechanical stress
in the substrate, the first planar Hall element for generating a first output signal responsive to the magnetic field, the
first magnetic field sensitivity, mechanical stress in the substrate, and the first mechanical stress sensitivity,

and wherein the second planar Hall element has a second sensitivity to the magnetic field and a second sensitivity to mechanical
stress in the substrate, the second planar Hall element for generating a second output signal responsive to the magnetic field,
the second magnetic field sensitivity, the mechanical stress in the substrate, and the second mechanical stress sensitivity.

US Pat. No. 9,825,528

COMPENSATING FOR VOLTAGE CHANGES IN DRIVER CIRCUITS

Allegro Microsystems, LLC...

1. An integrated circuit (IC) configured to receive an input signal comprising:
a boost duty cycle control circuit configured to provide duty cycle control to a power conversion stage configured to drive
a load, the power conversion stage configured to receive an input voltage;

a current control circuit configured to control current of a first current source coupled to the first load; and
an inverter configured to provide an output signal comprising a negative of the input voltage, the output of the inverter
configured to be coupled to the boost duty cycle control circuit.

US Pat. No. 9,804,222

MAGNETIC FIELD SENSOR WITH SHARED PATH AMPLIFIER AND ANALOG-TO-DIGITAL-CONVERTER

Allegro MicroSystems, LLC...

1. A magnetic field sensor comprising:
at least one magnetic field sensing element configured to generate a measured magnetic field signal responsive to an external
magnetic field and to generate a reference magnetic field signal responsive to a reference magnetic field;

a signal path comprising an amplifier and an analog-to-digital converter for processing the measured magnetic field signal
during a first time period to generate a sensor output signal indicative of the external magnetic field, and for processing
the reference magnetic field signal during a second time period, the analog-to-digital converter comprising at least one integrator
circuit having a first capacitor configured to process the measured magnetic field signal and a second capacitor configured
to process the reference magnetic field signal, wherein the analog-to-digital converter is responsive to the measured magnetic
field signal to generate a digital measured magnetic field signal and responsive to the reference magnetic field signal to
generate a digital reference magnetic field signal;

a controller configured to switch the first capacitor with the second capacitor to enable the first capacitor to process the
reference magnetic field signal; and

a comparator circuit to compare the reference magnetic field signal to a threshold value during the second time period to
determine whether a fault is present;

wherein the first time period and the second time period are non-overlapping time periods.

US Pat. No. 9,797,963

SYSTEMS AND METHODS FOR A MAGNETIC TARGET WITH MAGNETIC BIAS FIELD

Allegro MicroSystems, LLC...

1. An apparatus comprising:
a plurality of regions having juxtaposed edges and opposing ends, wherein adjacent ones of the plurality of regions have different
magnetic polarities;

a first magnetic strip, having a first magnetic polarity, and disposed at one end of the regions, wherein the first magnetic
polarity is a same polarity along the length of the first magnetic strip; and

a second magnetic strip, having a second magnetic polarity opposite to the first magnetic polarity, and disposed at a second
end of the regions to generate a magnetic bias across at least a portion of the regions to reduce instability in measuring
magnetic fields produced by the regions;

wherein the first magnetic strip and the second magnetic strip are discrete elements from the plurality of regions.

US Pat. No. 9,784,594

HALL-EFFECT BASED LINEAR MOTOR CONTROLLER

ALLEGRO MICROSYSTEMS, LLC...

1. A method of focusing a lens in a camera module having a voice coil actuator to effect displacement of the lens, comprising:
determining a displacement range value for the lens;
determining a per-frame value based on the displacement range value for the lens and a desired number of frames;
using the per-frame value and a current frame number to determine a value corresponding to a desired displacement of the lens;
and

providing a request comprising the value corresponding to the desired displacement of the lens as an input to a device that
adjusts a drive current supplied to a coil of the voice coil actuator according to the value corresponding to the desired
displacement of the lens and an internal feedback loop in the device until the desired displacement of the lens has been effected
by the voice coil actuator.

US Pat. No. 9,787,495

SIGNALING BETWEEN MASTER AND SLAVE COMPONENTS USING A SHARED COMMUNICATION NODE OF THE MASTER COMPONENT

Allegro Microsystems, LLC...

1. A network slave device comprising:
a transceiver for communicating over a communication bus in accordance with a point-to-point unidirectional network protocol,
wherein the point-to-point unidirectional network protocol is a single edge nibble transmission (SENT) protocol;

an address of the network slave device to identify the network slave device; and
a communication circuit configured to process a command received by the transceiver and generate a reply for transmission
over the communication bus if an address included in the command matches the address of the network slave device, wherein
the network slave device comprises a magnetic field sensor.

US Pat. No. 9,778,326

CIRCUITS AND METHODS FOR LIMITING A SMALLEST SEPARATION OF THRESHOLDS IN A MAGNETIC FIELD SENSOR

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
at least one magnetic field sensing element configured to generate a magnetic field signal influenced by a ferromagnetic object;
peak finding circuitry operable to identify at least one of a positive peak value or a negative peak value of the magnetic
field signal;

a threshold generation module coupled to receive the at least one of the positive peak value or the negative peak value, wherein
the threshold generation module comprises:

a peak-to-peak calculation module operable to determine a peak-to-peak value by using the at least one of the positive peak
value or the negative peak value;

a threshold calculation module operable to determine an upper threshold value and a lower threshold value based on the peak-to-peak
value, wherein the upper threshold value is a first predetermined percentage of the peak-to-peak value and the lower threshold
value is a second lower predetermined percentage of the peak-to-peak value; and

a threshold limiting module operable to identify a difference between the upper threshold value and the lower threshold value,
and, if the difference is smaller than a minimum separation value based on a function of an RMS noise level associated with
the magnetic field signal, operable to set the difference between the upper threshold value and the lower threshold value
to a corrected difference value.

US Pat. No. 9,753,097

MAGNETIC FIELD SENSORS AND ASSOCIATED METHODS WITH REDUCED OFFSET AND IMPROVED ACCURACY

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a circular vertical Hall (CVH) sensing element comprising:
a plurality of vertical Hall elements arranged over a common implant and diffusion region in a substrate, wherein the plurality
of vertical Hall elements is configured to generate a plurality of magnetic field signals, each magnetic field signal responsive
to a magnetic field; the magnetic field sensor further comprising:

a sequence switches circuit coupled to the plurality of vertical Hall elements, wherein the sequence switches circuit is operable
to select from among the plurality of vertical Hall elements, and wherein the sequence switches circuit is configured to supply
a current signal or a voltage signal to the plurality of vertical Hall elements, wherein each selected one of the plurality
of vertical Hall elements comprises a respective plurality of active vertical Hall element contacts and at least one respective
skipped contact, the at least one skipped contact disposed between at least one respective pair of the respective plurality
of active vertical Hall element contacts, wherein a position of the at least one skipped contact is selected to reduce an
offset voltage of a respective one of the plurality of vertical Hall elements,

wherein the respective at least one skipped contact for each selected one of the plurality of vertical Hall elements is not
coupled to receive the current signal or the voltage signal, is not configured to couple to a reference potential, and an
output signal of the sequence switches circuit is not configured to be generated by the respective at least one skipped contact.

US Pat. No. 9,666,788

INTEGRATED CIRCUIT PACKAGE HAVING A SPLIT LEAD FRAME

ALLEGRO MICROSYSTEMS, LLC...

1. A magnetic field sensor comprising:
a lead frame having a first surface, a second opposing surface, and comprising a plurality of leads, wherein at least two
of the plurality of leads are electrically isolated from each other and wherein each of the at least two leads has a connection
portion extending adjacent to the connection portion of the other one of the at least two leads and a die attach portion having
a width larger than a width of the respective connection portion;

a semiconductor die having a first surface supporting a magnetic field sensing element and at least two bond pads, wherein
the first surface is disposed proximal to and attached to the die attach portions of the at least two electrically isolated
leads, and a second opposing surface is disposed distal from the die attach portions of the at least two electrically isolated
leads, wherein the die attach portion of each of the at least two electrically isolated leads has a reduced area with respect
to other areas of the die attach portion, wherein the reduced area is opposite and adjacent to a reduced area of the die attach
portion of the other one of the at least two electrically isolated leads, and wherein the magnetic field sensing element and
the at least two bond pads are disposed between the reduced area of the die attach portions of the at least two electrically
isolated leads;

a non-conductive adhesive disposed between the semiconductor die and the die attach portion of the at least two electrically
isolated leads;

at least one wire bond coupled between at least one of the at least two bond pads of the die and the first surface of the
lead frame, wherein the die is attached to the second surface of the lead frame;

a non-conductive mold material enclosing the semiconductor die and the die attach portion of the at least two electrically
isolated leads; wherein any connection portions of any of the plurality of leads extending beyond the non-conductive mold
material extend from a single side of the non-conductive mold material; and

a ferromagnetic mold material secured to a portion of the non-conductive mold material.

US Pat. No. 9,625,534

SYSTEMS AND METHODS FOR DETECTION OF MAGNETIC FIELDS

Allegro MicroSystems, LLC...

1. An electronic circuit comprising:
a first magnetic field detection circuit that produces a first signal indicating a strength of a magnetic field;
a second magnetic field detection circuit that selectively receives a power signal and produces a second signal indicating
the strength of the magnetic field, wherein the second signal provides a more accurate indication of the strength of the magnetic
field than the first signal; and

a control circuit configured to determine whether the first signal indicates a change greater than a predetermined amount
in the strength of the magnetic field and to couple the power signal to the second magnetic field detection circuit in response
to a determination that the strength of the magnetic field has changed by greater than the predetermined amount;

an output circuit that provides, as an output of the electronic circuit, an output signal that is based only on the second
signal produced by the second magnetic field detection circuit while the second magnetic field detection circuit is receiving
power.

US Pat. No. 9,541,424

CIRCUITS AND METHODS FOR PROCESSING SIGNALS GENERATED BY A CIRCULAR VERTICAL HALL (CVH) SENSING ELEMENT IN THE PRESENCE OF A MULTI-POLE MAGNET

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a semiconductor substrate having a first surface in a coordinate plane;
a Circular Vertical Hall (CVH) sensing element comprised of a plurality of vertical Hall elements, wherein each one of the
plurality of vertical Hall elements is arranged upon a common circular implant region in the first surface of the semiconductor
substrate, wherein the plurality of vertical Hall elements is configured to generate a plurality of output signals responsive
to a magnetic field having a direction component, wherein the CVH sensing element is configured to generate a CVH output signal
comprised of the plurality of output signals, wherein the magnetic field results from a multi-pole magnet disposed proximate
to the magnetic field sensor and having a plurality of north poles and a plurality of south poles, each north pole proximate
to at least one south pole;

an angle sensing circuit coupled to receive the CVH output signal and configured to generate an angle signal representative
of an angle of the direction component of the magnetic field as the multi-pole magnet and the CVH sensing element move relative
to each other;

a pole pair counting module coupled to receive a signal representative of the angle signal and configured to generate a count
signal representative of a count of a number of the pole pairs of the multi-pole magnet that move past the CVH sensing element;
and

an angle interpolation module coupled to receive the angle signal and the count signal, the angle interpolation module configured
to generate a reconstructed angle signal representative of an angular position of the multi-pole magnet relative to the CVH
sensing element, the reconstructed angle signal generated based upon the count signal and the angle signal, the reconstructed
angle signal having a higher resolution than the angle signal.

US Pat. No. 9,476,899

CIRCUITS AND METHODS FOR GENERATING A THRESHOLD SIGNAL USED IN A MOTION DETECTOR IN ACCORDANCE WITH A LEAST COMMON MULTIPLE OF A SET OF POSSIBLE QUANTITIES OF FEATURES UPON A TARGET

Allegro MicroSystems, LLC...

1. A magnetic field sensor for detecting a movement of an object, wherein the object has a plurality of object features, wherein
a quantity of the object features belongs to a set of possible quantities of object features, wherein the set has a least
common multiple of possible quantities of object features, wherein the magnetic field sensor comprises:
a magnetic field sensing element for generating a magnetic field signal responsive to the object features as they pass by
the magnetic field sensing element, wherein the magnetic field signal comprises a plurality of magnetic field signal cycles,
wherein each one of the plurality of magnetic field signal cycles is indicative of a respective one of the plurality of object
features passing by the magnetic field sensing element, wherein the plurality of magnetic field signal cycles includes a present
magnetic field signal cycle and a plurality of past magnetic field signal cycles; and

a motion detector coupled to the magnetic field sensing element and configured to generate a motion signal indicative of the
movement of the object, wherein the motion signal has a plurality of rising edges and a plurality of falling edges, wherein
each rising edge and each falling edge is associated with a respective one of the plurality of magnetic field signal cycles,
wherein the motion detector comprises:

a peak identifying circuit for identifying at least one of a plurality of positive peaks of the magnetic field signal or a
plurality of negative peaks of the magnetic field signal to provide a peak signal indicative of the at least one of the plurality
of positive peaks of the magnetic field signal or of the plurality of negative peak of the magnetic field signal;

a sample selection circuit module coupled to receive a peak-related signal related to the peak signal and configured to store
a plurality of samples of the peak-related signal, wherein the sample selection circuit module is further configured to sequentially
recall stored samples of the peak-related signal from the stored plurality of samples to generate a sampled signal, wherein
each sequentially selected stored sample within the sampled signal is associated with a respective one of the plurality of
prior cycles of the magnetic field signal that occurred a quantity of prior cycles ago equal to an integer multiple of the
least common multiple of the possible quantities of the object features; and

a comparator coupled to receive a signal related to the sampled signal, coupled to receive the magnetic field signal, and
configured to compare the signal related to the sampled signal with the magnetic field signal in order to generate the motion
signal.

US Pat. No. 10,048,718

JOYSTICK ASSEMBLY

ALLEGRO MICROSYSTEMS, LLC...

1. A joystick assembly for use with a device comprising a joystick surface and a first magnet having north and south magnetic poles, comprising:a second magnet having north and south magnetic poles; and
a movable elongated shaft having first and second opposing ends arranged along a major axis of the shaft, the first end coupled to the second magnet such that movement of the shaft results in movement of the second magnet relative to the first magnet such that a line between centers of the north and south magnetic poles of the second magnet is movable relative to a line between the north and south magnetic poles of the first magnet, wherein an attraction of the second magnet to the first magnet results in a restoring force upon the shaft, and wherein the shaft and the second magnet are removable from the joystick surface.

US Pat. No. 9,960,716

CONTROL TIMING AND SEQUENCING FOR A MULTI-PHASE ELECTRIC MOTOR

Allegro MicroSystems, LLC...

1. An electronic circuit for controlling a motor, comprising:a magnetic field sensing circuit responsive to a plurality of magnetic field sensing elements disposed to sense rotation of the motor and configured to generate a respective plurality of magnetic field signals, each having a respective state indicative of a rotational position of the motor;
a position and speed sensing circuit configured to generate a signal representative of at least one of the rotational position of the motor and a rotational speed of the motor, wherein the position and speed sensing circuit tracks state changes of the plurality of magnetic field signals; and
a gate driver circuit configured to generate one or more motor drive signals that drive the motor based, at least in part, upon the sensed rotational position, wherein the one or more motor drive signals control a voltage applied to the motor;
wherein the position and speed sensing circuit is configured to generate at least one qualified control signal based upon a determined valid state change of the plurality of magnetic field signals, and
wherein the gate driver circuit is configured to generate the one or more motor drive signals based, at least in part, upon the qualified control signal,
wherein the position and speed sensing circuit is configured to modify one or more status indicators based upon the state of the plurality of magnetic field signals, wherein the one or more status indicators comprise:
a previous state indicator associated with at least one previous state of the plurality of magnetic field signals;
a current state indicator associated with a current state of the plurality of magnetic field signals; and
a motor direction indicator, wherein the motor direction indicator is set to one of a plurality of values based upon a detected direction of rotation of the motor and a desired direction of rotation of the motor
wherein the position and speed sensing circuit is configured to:
determine that an invalid state change of the plurality of magnetic field signals has occurred when the motor direction indicator is not set and the current state indicator is not equal to an expected value determined based upon the previous state indicator, wherein no qualified control signal is generated for each invalid state change.

US Pat. No. 9,851,416

SYSTEMS AND METHODS FOR MAGNETIC FIELD SENSORS WITH SELF-TEST

Allegro MicroSystems, LLC...

1. An apparatus comprising:
a detection circuit to detect speed and direction of a target, the detection circuit comprising:
one or more magnetic field sensing elements;
a first signal channel to output a first signal;
a second signal channel to output a second signal, wherein the first and second signals correspond to a position of the target
in relation to the one or more magnetic field sensing elements;

an oscillator to provide an oscillating output; and
an analog-to-digital converter;
a first test circuit to determine if the apparatus is detecting speed and/or direction accurately, the first test circuit
comprising a counter coupled to the signal channels such that the first signal channel increments the counter and the second
signal channels decrements the counter, the first test circuit including circuitry to assert an error condition if a count
of the counter exceeds a predetermined threshold;

a second test circuit coupled to the oscillator to determine whether the oscillator is oscillating within a predetermined
frequency range, the second test circuit comprising a ramp generator to generate a voltage ramp signal that decays over time
and resets upon detection of an edge of the oscillating output, and a comparator circuit to determine whether a voltage level
of the voltage ramp signal is between a predetermined voltage range upon detection of the edge of the oscillating output;

a third test circuit coupled to the analog-to-digital converter to determine whether the analog-to-digital converter is operating
with an expected accuracy, the third test circuit comprising an output to inject an analog test signal into an input of the
analog-to-digital converter, an input coupled to receive a digital signal from the analog-to-digital converter representing
a conversion of the analog test signal; and a comparator circuit to compare the digital signal to an expected value; and

a fourth test circuit coupled to receive the digital signal from the analog-to-digital converter, compute a rate of change
of the output of the analog-to-digital converter, and determine whether the rate of change is within a predetermined range
defined by a mechanical system to which the target is attached.

US Pat. No. 9,843,285

DIGITAL DEMODULATOR FOR PULSE-WIDTH MODULATED (PWM) SIGNALS IN A MOTOR CONTROLLER

Allegro MicroSystems, LLC...

1. An electronic circuit for digitally demodulating a pulse-width modulated (PWM) signal in a motor control system, the electronic
circuit comprising:
an input configured to receive a speed demand signal, the speed demand signal comprising a PWM signal, wherein a duty cycle
of the PWM signal is associated with a requested speed of a motor coupled to the electronic circuit;

a PWM demodulator configured to demodulate the PWM signal and generate an N-bit digital speed value representative of the
requested speed of the motor, wherein N is a positive integer;

a motor driver configured to generate, based at least in part upon the N-bit digital speed value, one or more control signals
to operate the motor;

a multiplexer configured to select between a first digital value and a second digital value to provide a selected digital
output value, the selection based upon a logic level of the PWM signal; and

a digital low-pass filter configured to filter the selected digital output value to generate the N-bit digital speed value,
wherein for a current sample of the selected digital output value, the low-pass filter is configured to:

subtract a digital feedback value from the current selected digital output value to generate a first intermediate value;
subtract the digital feedback value from a previous N-bit digital speed value to generate a second intermediate value;
subtract the previous N-bit digital speed value from the digital feedback value to generate a third intermediate value and
accumulate the third intermediate value for a window of Xsamples, wherein Xis a positive integer;

add the first intermediate value and the second intermediate value and accumulate the sums for a window of Xsamples as an
accumulated sum value;

multiply the accumulated third intermediate values by a gain factor to generate an intermediate gain value;
add the intermediate gain value and the accumulated sum value to generate an intermediate feedback value;
divide the intermediate feedback value by a time factor to generate the digital feedback value; and
divide the accumulated third intermediate values by a time factor to generate the N-bit digital speed value.

US Pat. No. 9,823,092

MAGNETIC FIELD SENSOR PROVIDING A MOVEMENT DETECTOR

Allegro Microsystems, LLC...

1. A magnetic field sensor for measuring movement of a target object, the movement in an x-z plane within x-y-z Cartesian
coordinates with x, y, and z orthogonal axes, the magnetic field sensor comprising:
a substrate having a major planar surface within about twenty degrees of parallel to the x-z plane; and
a plurality of magnetic field sensing elements disposed upon the major planar surface of the substrate, each one of the plurality
of magnetic field sensing elements having a major response axis parallel to the major planar surface of the substrate, wherein
the plurality of magnetic field sensing elements is configured to generate a respective plurality of magnetic field signals;
and

an electronic circuit disposed upon the substrate and coupled to the plurality of magnetic field sensing elements, the electronic
circuit comprising:

at least one analog or digital comparator configured to compare each respective one of the plurality of magnetic field signals
to a respective threshold signal to generate a respective plurality of binary signals, states of the plurality of binary signals
indicative of a position of the target object; and

a non-volatile memory device coupled to the plurality of binary signals, wherein the non-volatile memory device is operable
to decode the plurality of binary signals to generate a corresponding non-volatile memory device output signal, wherein the
non-volatile memory device output signal is indicative of a speed and a direction of the movement of the target object.

US Pat. No. 9,780,706

MOTOR CONTROL CURRENT ZERO CROSSING DETECTOR

Allegro MicroSystems, LLC...

1. A driver circuit for driving a load, the driver circuit comprising:
a gate driver for providing an associated control signal to each of one or more switching elements coupled to the driver circuit,
a first one of the switching elements coupled between a high supply voltage and a switching node of the load, and a second
one of the switching elements coupled between the switching node and a low supply voltage; and

a zero crossing detector for detecting a zero crossing of a signal of the one or more switching elements and the load, the
zero crossing detector comprising:

a first counter coupled to the switching node, wherein the first counter is configured to count in a predetermined direction
based on a detected voltage of the switching node;

a second counter coupled to one of the control signals, wherein the second counter is configured to count in a predetermined
direction based on a detected voltage of the control signal; and

an output comparator coupled to the first counter and the second counter, the output comparator to generate a difference between
a count value of the first counter and a count value of the second counter, wherein the zero crossing detector is configured
to generate a zero crossing output signal based, at least in part, upon the difference.

US Pat. No. 9,739,848

CIRCULAR VERTICAL HALL (CVH) SENSING ELEMENT WITH SLIDING INTEGRATION

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:
a circular vertical Hall (CVH) sensing element comprising a plurality of vertical Hall elements, each vertical Hall element
comprised of a respective group of vertical Hall element contacts selected from among a plurality of vertical Hall element
contacts, the plurality of vertical Hall element contacts arranged over a common implant region in a semiconductor substrate,
adjacent ones of the plurality of contacts at predetermined angles from each other;

a CVH output stage comprising one or more drive circuits to drive the plurality of vertical Hall elements in a sequential
order and produce an analog signal representing a strength of an external magnetic field as detected by the plurality of vertical
Hall elements, the analog signal comprising a series of measurements from the vertical Hall elements;

an analog-to-digital converter coupled to receive the analog signal and produce a digital signal;
a quadrature modulator circuit coupled to the digital signal and operable to generate a plurality of quadrature modulated
signals; and

a processor stage coupled to receive the signals representative of the plurality of quadrature modulated signals, and operable
to perform a sliding window integration using the signals representative of the plurality of quadrature modulated signals;
and

compute an estimated angle of the external magnetic field using the signals representative of the plurality of quadrature
modulated signals.

US Pat. No. 9,774,257

CONTROL CIRCUIT FOR A SWITCHING REGULATOR DRIVING AN LED LOAD WITH CONTROLLED PWM DIMMING

ALLEGRO MICROSYSTEMS, LLC...

1. A switching regulator control circuit for controlling a switching regulator comprising a switch that conducts to transfer
energy from an input source to an output at which a regulated output is provided to an LED load, the switching regulator control
circuit comprising:
a circuit configured to generate a control signal to control conduction of the switch and having a first input responsive
to a reference signal, a second input responsive to a feedback signal proportional to the regulated output, and an output
at which the control signal is provided, wherein the reference signal is ramped to control a rate of change of the regulated
output; and

a logic circuit coupled to receive the control signal at the output of the circuit and configured to selectively couple the
control signal to the switch in response to a PWM signal in order to dim the LED load, wherein the reference signal is ramped
in response to an edge of the PWM signal, wherein the regulated output is a current and the reference signal is ramped down
to control a rate of decrease of the regulated output and wherein the PWM signal is a delayed version of an external digital
signal.

US Pat. No. 9,739,637

MAGNETIC FIELD MOTION SENSOR AND RELATED TECHNIQUES

Allegro MicroSystems, LLC...

1. A magnetic field sensor for detecting motion of an object, comprising:
a plurality of magnetic field sensing elements configured to generate at least two magnetic field signals each having an amplitude
dependent on a magnetic field associated with the object and a respective phase;

a processor configured to process the magnetic field signals, comprising:
a vector angle generator to generate a plurality of vector angle values indicative of angular position of the object, the
vector angle values being generated as a function of the magnetic field signals; and

a vector angle comparator responsive to the vector angle values to generate a comparator output signal indicative of a difference
between the plurality of vector angle values; and

an output signal generator coupled to the vector angle comparator and configured to generate a sensor output signal in response
to the comparator output signal, wherein the sensor output signal is indicative of one or more conditions comprising: an absence
of normal rotation of the object, a direction change of the motion of the object, and a vibration of the object.

US Pat. No. 9,698,742

ELECTRONIC AMPLIFIER WITH A FEEDBACK CIRCUIT THAT INCLUDES A TRANSCONDUCTANCE AMPLIFIER

Allegro Microsystems, LLC...

1. An electronic amplifier circuit, comprising:
a voltage amplifier having a first input node and a voltage output node, wherein the first input node of the voltage amplifier
is coupled to a first summing node, wherein the first summing node is coupled to receive a first input current signal;

a feedback circuit having an input node and a first output node, wherein the feedback circuit comprises:
a sensing circuit having an input node and an output node, wherein the input node of the sensing circuit, the input node of
the feedback circuit, and the output node of the voltage amplifier are coupled together; and

a first transconductance amplifier having an input node and a first output node, wherein the output node of the sensing circuit
is coupled to the input node of the first transconductance amplifier, wherein the first output node of the first transconductance
amplifier, the first output node of the feedback circuit, and the first input node of the voltage amplifier are coupled together
at the first summing node, wherein the first transconductance amplifier is operable to generate a first feedback current signal
at the first summing node, wherein the first feedback current signal and the first input current signal are coupled together
at the first summing node to provide a sum of the first input current signal and the first feedback current signal at the
first summing node, wherein a value of an impedance of the output node of the sensing circuit varies with a value of a power
supply voltage coupled to the sensing circuit, wherein the first feedback current signal is unaffected by the value of the
power supply voltage.

US Pat. No. 9,638,766

MAGNETIC FIELD SENSOR WITH IMPROVED ACCURACY RESULTING FROM A VARIABLE POTENTIOMETER AND A GAIN CIRCUIT

Allegro Microsystems, LLC...

1. A magnetic field sensor, comprising:
a plurality of magnetic field sensing elements, each one of the plurality of magnetic field sensing elements having a respective
plurality of contacts, wherein the plurality of magnetic field sensing elements is configured to generate a plurality of magnetic
field signals, each magnetic field signal responsive to a magnetic field;

a sequence switches circuit coupled to the plurality of magnetic field sensing elements, wherein the sequence switches circuit
is coupled to receive a control signal and, in response to the control signal, the sequence switches circuit is configured
to sequentially select from among the plurality of magnetic field signals to generate a sequenced output signal representative
of sequentially selected ones of the plurality of magnetic field signals;

a memory device configured to store a plurality of potentiometer control values; and
a variable potentiometer coupled to the sequence switches circuit, wherein the variable potentiometer is configured to attenuate
an offset of each one of the plurality of magnetic field signals within the sequenced output signal by using a respective
plurality of offset attenuation factors responsive to one or more of the plurality of potentiometer control values to generate
an offset attenuated sequence output signal, wherein each one of the plurality of offset attenuation factors is related to
a respective error voltage of a respective one of the plurality of magnetic field signals; and

a gain circuit coupled to receive a signal representative of the offset attenuated sequenced output signal, wherein the gain
circuit has a gain selected such that the gain circuit is configured to generate a clamped sequenced output signal having
a predetermined number of samples between clamping levels of the gain circuit, wherein the predetermined number is substantially
less than half a number of the plurality of magnetic field sensing elements in the magnetic field sensor.

US Pat. No. 9,634,715

SIGNALING BETWEEN MASTER AND SLAVE COMPONENTS USING A SHARED COMMUNICATION NODE OF THE MASTER COMPONENT

Allegro Microsystems, LLC...

17. A system comprising:
a controller coupled to a communication bus and configured to communicate over the communication bus in accordance with a
point-to-point communication protocol to send a series of commands over the communication bus; and

one or more sensors coupled to the communication bus to communicate over the communication bus in accordance with the point-to-point
communication protocol, each of the sensors having a respective address to identify the respective sensor and configured to
respond to a command in the series of commands that has a position within the series that matches the respective address of
the respective sensor;

wherein the one or more sensors each comprise a counter configured to count the number of commands sent by the controller,
and wherein the one or more sensors are configured to reset their counters when a number of commands sent by the controller
matches or exceeds a number of sensors coupled to the communication device.

US Pat. No. 9,583,247

SYSTEMS AND METHODS FOR A MAGNET WITH UNIFORM MAGNETIC FLUX

Allegro MicroSystems, LLC...

1. A magnetic field sensor comprising:
a magnet comprising:
a magnetic body having a length and width;
a first triangular notch in a first side of the body and extending along a portion of the length of the body; and
a second triangular notch in an opposite side of the body extending along portion of the length of the body, wherein a length
of the first and second triangular notch is less than the length of the body and a magnetic field produced by the body has
a substantially uniform magnetic flux along at least a portion of the length of the body; and

three magnetic field sensing elements arranged in a linear array positioned such that each of the three magnetic field sensing
elements is positioned within the area of substantially uniform magnetic flux.

US Pat. No. 9,575,103

INTEGRATED CIRCUIT AND ASSOCIATED METHODS FOR MEASUREMENT OF AN EXTERNAL IMPEDANCE

ALLEGRO MICROSYSTEMS, LLC...

1. An integrated circuit comprising:
an output circuit having a first terminal adapted to couple to an external power supply, a second terminal adapted to couple
to a reference potential, and a third, control terminal, wherein the first and second terminals provide output terminals of
the integrated circuit; and

an impedance measurement circuit responsive to the external power supply to generate a control signal for coupling to the
control terminal of the output circuit and to monitor an output signal of the integrated circuit for an oscillation, wherein
the control signal controls a current level associated with the output circuit, and wherein the oscillation of the output
signal is indicative of an external impedance associated with the integrated circuit.

US Pat. No. 9,523,742

CIRCUITS AND METHODS FOR MODULATING CURRENT IN CIRCUITS COMPRISING SENSING ELEMENTS

Allegro MicroSystems, LLC...

1. A circuit, comprising:
a current source having at least a first terminal and a second, control terminal, said current source configured to receive
a current control signal at the control terminal and in response thereto generate a first current signal at the first terminal,
wherein the current control signal controls a current level of the first current signal;

at least one sensing element responsive to one or more sense parameters and having an input adapted to couple to the first
terminal of said current source, said sensing element configured to receive one or more current signals comprising at least
the first current signal at the input thereof and in response thereto generate a sensed output signal at an output thereof;

a gain adjustable circuit having at least a first, input terminal, a second, control terminal, and a third, output terminal,
said gain adjustable circuit configured to receive a signal representative of the sensed output signal at the input terminal,
a gain control signal at the control terminal, and in response thereto provide a gain adjusted signal having an associated
gain level at the output terminal, wherein the gain control signal controls gain of said gain adjustable circuit; and

a controller configured to provide at least the current control signal to the control terminal of said current source and
the gain control signal to the control terminal of said gain adjustable circuit,

wherein in response to an output of said circuit being at or near a first switchpoint corresponding to one or more of the
sense parameters being greater than a threshold value, a current level of the current signals received by said sensing element
is configured to be increased from a first current level to a second, higher current level of a plurality of current levels
and the gain of said gain adjustable circuit is configured to be decreased from a second gain level to a first, lower gain
level of a plurality of gain levels, wherein the gain level of the gain adjusted signal remains substantially constant.

US Pat. No. 10,088,533

INTEGRATED MAGNETIC FIELD SENSOR AND METHOD OF POWERING ON AND OFF A LOAD

Allegro MicroSystems, Inc...

1. An integrated magnetic field sensor comprising:a semiconductor substrate disposed within an integrated circuit package, wherein the integrated circuit package comprises a thermal pad configured to thermally couple the substrate to a circuit board;
a magnetic field sensing circuit disposed upon or within the substrate and operable to generate a two-state signal responsive to a magnetic field; and
a power driving circuit disposed upon or within the substrate and operable to generate, in response to the two-state signal, a power driving signal having a higher power state and a lower power state.

US Pat. No. 10,038,001

HYBRID ELECTRICALLY ERASABLE PROGRAMMABLE READ-ONLY MEMORY (EEPROM) SYSTEMS AND METHODS FOR FORMING

Allegro Microsystems, LLC...

1. A hybrid electrically erasable programmable read only (EEPROM) memory cell comprising:a programmable capacitor disposed on a substrate, the programmable capacitor comprising:
a floating gate forming a first polysilicon layer, the floating gate having first and second opposing surfaces;
an oxide-nitride-oxide (ONO) layer disposed over the first surface of the floating gate, the ONO layer having first and second opposing surfaces;
a control gate forming a second polysilicon layer, the control gate formed over the first surface of the ONO layer to form a hybrid EEPROM comprising a single polysilicon EEPROM and a double polysilicon EEPROM, the single polysilicon EEPROM comprising the first polysilicon layer and the double polysilicon EEPROM comprising the first and second polysilicon layers;
a first N-type region formed over a first surface of the substrate;
a first P-type region formed over a first surface of the first N-type region;
a second P-type region formed over a first surface of the first P-type region, wherein the first and second P-type regions have different doping levels;
a second N-type region formed over a first surface of the second P-type region;
a third N-type region extending into the second N-type region; and
fourth and fifth N-type regions formed in the third N-type region, wherein a first metal contact is coupled to the control gate through a first via, a second metal contact is coupled to the fourth N-type region through a second via and a third metal contact is coupled to the fifth N-type region through a third via.

US Pat. No. 10,026,425

DOUBLE PINNED MAGNETORESISTANCE ELEMENT WITH TEMPORARY FERROMAGNETIC LAYER TO IMPROVE ANNEALING

Allegro MicroSystems, LLC...

1. A magnetoresistance element deposited upon a substrate, comprising:a plurality of layers deposited in a stack of layers upon the substrate, the stack of layers comprising first and second antiferromagnetic pinning layers and a free layer structure disposed between the first and second antiferromagnetic pinning layers; and
a temporary ferromagnetic layer deposited over a top of the stack of layers, the top being distal from the substrate.

US Pat. No. 10,006,970

ELECTRONIC COMPARISON CIRCUIT TO IDENTIFY AT LEAST THREE CONDITIONS OF AN INPUT SIGNAL

Allegro MicroSystems, LLC...

1. A circuit comprising:a comparison circuit, the comparison circuit comprising:
a comparator having first and second comparator inputs and a comparator output;
a first switching circuit having a first terminal coupled to the first comparator input and a second terminal coupled to the second comparator input, and a second switching circuit having a first terminal coupled to the first comparator input and a second terminal coupled to the second comparator input, each switching circuit comprising two transistors and a current source output coupled between the two transistors;
first and second logic gates coupled to the output of the comparator, each of the logic gates having a control terminal to be coupled to different control signal outputs of a logic circuit, wherein when the control signals of the logic circuit are modulated an output signal of the first logic gate and an output signal of the second logic gate together have one of first, second and third states corresponding to one of first, second and third conditions, respectively, of an input signal to the comparison circuit.

US Pat. No. 9,941,999

METHODS AND APPARATUS FOR COMMUNICATION OVER AN ISOLATION BARRIER WITH MONITORING

Allegro MicroSystems, LLC...

1. A method, comprising:receiving an input data stream having first and second states;
generating a first pulse train type for the first state;
generating a second pulse train type for second state, the first and second pulse train types comprising different characteristics, wherein the first pulse train type includes pulses corresponding to rising and falling edges of the first and second states and refresh pulses, and wherein the refresh pulses for the first state comprise a first repetition rate and refresh pulses for the second state comprise a second repetition rate which is different than the first repetition rate;
transmitting the first and second pulse train types across a voltage barrier of a digital signal isolator;
receiving pulses for the transmitted first and second pulse train types from the voltage barrier;
demodulating the first and second pulse trains types to recover the input data stream in an output data stream; and
setting a signal integrity timeout to detect a lack of pulses received or transmitted for the first and second pulse train types corresponding to a fault condition.

US Pat. No. 9,797,746

SYSTEMS AND METHODS FOR DETECTING A MAGNETIC TARGET BY COMPUTING A BARYCENTER

Allegro MicroSystems, LLC...

1. A system comprising:
a plurality of magnetic field sensing elements arranged about a central point, each one of the plurality of magnetic field
sensing elements configured to measure a magnetic field produced by a magnetic target and provide a respective output signal
that represents a respective measurement of a strength of the magnetic field; and

a processor circuit coupled to receive the output signal from each one of the plurality of magnetic field sensing elements
and determine a barycenter of the measurements of the magnetic field based on a position of the magnetic field sensing elements,
wherein determining the barycenter includes calculating a two-dimensional position of the barycenter that represents a two-dimensional
position of the magnetic target in a plane defined by the magnetic field sensing elements.

US Pat. No. 9,797,961

MAGNETIC FIELD SENSOR WITH DELAYED OUTPUT

Allegro MicroSystems, LLC...

1. A system comprising:
a clock circuit generating a sample clock signal having a predetermined sample clock period;
a sampling circuit to generate samples of a received signal during each sample clock period;
an interpolation circuit to:
estimate at least one value of the received signal at times between the samples of the received signal, the at least one estimated
value corresponding to a threshold value and based on at least a first sample and a second sample of the received signal;

estimate a time that the received signal crosses the threshold by using the estimated values; and
determine a time delta between the first sample and the estimated time that the received signal crosses the threshold; and
a delay circuit to generate a time delay substantially equal to the time delta; and
a synchronization circuit to periodically synchronize the delay circuit so that a maximum delay generated by the delay circuit
is substantially equal to the sample clock period, wherein the synchronization circuit comprises a control feedback loop.

US Pat. No. 9,781,789

APPARATUS AND METHODS FOR LED CONTROL

Allegro Microsystems, LLC...

1. An LED driver configured to drive an LED load comprising a plurality of series-coupled LEDs, the LED driver comprising:
a bypass switch having a first terminal coupled to an intermediate node of the series-coupled LEDs and a second terminal coupled
to a reference potential, wherein the intermediate node is disposed between a first portion and a second portion of the series-coupled
LEDs; and

a slew rate control circuit responsive to a command input signal and to a feedback voltage associated with the bypass switch,
the slew rate control circuit configured to generate a bypass switch control signal with a controllable slew rate for coupling
to a control terminal of the bypass switch;

wherein the slew rate control circuit is further configured to detect a rate of change of the feedback voltage and wherein
the controllable slew rate of the bypass switch control signal is established in response to the detected rate of change of
the feedback voltage.

US Pat. No. 9,735,345

VERTICAL HALL EFFECT SENSOR

Allegro MicroSystems, LLC...

1. A magnetic field sensing device comprising:
a plurality of vertical Hall effect sensors, each vertical Hall sensor comprising:
a plurality of semiconductor electrodes; and
a plurality of electrically floating semiconductor fingers interdigitated between the plurality of electrodes wherein the
plurality of vertical Hall effect sensors is built within at least one surface of a semiconductor wafer and arranged in a
circle, and

wherein each vertical Hall effect sensor is configured to measure the magnetic field in a direction radially inward to or
outward from a center of the semiconductor wafer,

wherein the plurality of semiconductor electrodes comprising:
a source electrode;
a first sensing electrode and a second sensing electrode, arranged such that the source electrode is between the first sensing
electrode and the second sensing electrode; and

a first drain electrode and a second drain electrode, arranged such that the first sensing electrode, second sensing electrode,
and source electrode are between the first drain electrode and the second drain electrode; and

wherein the plurality of semiconductor fingers interdigitated with the plurality of semiconductor electrodes comprises a first
semiconductor finger of the plurality of semiconductor fingers disposed between the source electrode and the first sensing
electrode.

US Pat. No. 9,735,773

SYSTEMS AND METHODS FOR SENSING CURRENT THROUGH A LOW-SIDE FIELD EFFECT TRANSISTOR

Allegro Microsystems, LLC...

1. An apparatus comprising:
a switching circuit coupled to a load and a reference node, the switching circuit capable of conducting a reverse current
from the reference node to the load when a voltage at the load is lower than a voltage at the reference node;

a voltage source having a first terminal coupled to the load, a second terminal configured to follow a voltage at the load,
and produce a voltage indicative of a voltage drop across the switching circuit; and

a comparator circuit coupled to compare a voltage at the second terminal of the voltage source to the voltage at the reference
node and configured to indicate when the reverse current has a magnitude greater than a predetermined threshold.

US Pat. No. 9,720,054

MAGNETIC FIELD SENSOR AND ELECTRONIC CIRCUIT THAT PASS AMPLIFIER CURRENT THROUGH A MAGNETORESISTANCE ELEMENT

Allegro MicroSystems, LLC...

1. An electronic circuit coupled to receive a power supply voltage, comprising:
a first magnetoresistance element having first and second terminals;
a first transistor having a control node, a first current passing node, and a second current passing node;
a first voltage generating source having first and second nodes between which a first fixed voltage is generated, wherein
the first terminal of the first magnetoresistance element is coupled to the first current passing node of the first transistor,
wherein the first node of the first voltage generating source is coupled to the control node of the first transistor and the
second node of the first voltage generating source is coupled to the second terminal of the first magnetoresistance element,
wherein the electronic circuit is operable to generate a first current signal at the second current passing node of the first
transistor related to a resistance value of the first magnetoresistance element;

a second magnetoresistance element having first and a second terminals;
a second transistor having a control node, a first current passing node, and a second current passing node;
a second voltage generating source having first and second nodes between which a second fixed voltage is generated; anda load coupled to the second current passing node of the first transistor, wherein the second current passing node of the
first transistor is coupled to the second current passing node of the second transistor, wherein the first terminal of the
second magnetoresistance element is coupled to the first current passing node of the second transistor, wherein the first
node of the second voltage generating source is coupled to the control node of the second transistor and the second node of
the second voltage generating source is coupled to the second terminal of the second magnetoresistance element, wherein the
electronic circuit is operable to generate a second current signal at the second current passing node of the second transistor
related to a resistance value of the second magetoresistance element, wherein a current passing through the load is equal
to a difference between the first current signal and the second current signal, wherein the second terminals of the first
and second magnetoresistance elements are not coupled together.

US Pat. No. 9,618,400

TEMPERATURE DETECTION CIRCUIT FOR A MAGNETIC SENSOR

ALLEGRO MICROSYSTEMS, LLC...

1. A temperature detection circuit comprising:
a first circuit configured to provide a first signal to enable determination of a parameter of the magnetic sensor; and
a comparator circuit configured to provide a warning signal in response to the first signal if a temperature reaches a temperature
value,

wherein the first circuit comprises a thermal voltage reference circuit configured to provide the first signal,
wherein the thermal voltage reference circuit comprises a first transistor in parallel with a first resistor and a second
transistor,

wherein a first current across the first transistor is equal to a second current across the first resistor, and
wherein a first voltage across the first transistor is equal to a second voltage across the first resistor and the second
transistor.

US Pat. No. 10,073,136

METHODS AND APPARATUS FOR SENSOR DIAGNOSTICS INCLUDING SENSING ELEMENT OPERATION

ALLEGRO MICROSYSTEMS, LLC...

1. An integrated circuit (IC), comprising:a magnetic sensing element having differential first and second outputs and an input, the input to receive current from a current source;
first and second switches coupled to a respective one of the differential first and second outputs;
a first voltage source coupled between the first and second switches, the first and second switches having a first state in which the first voltage source is coupled across the differential first and second outputs such that the first output, the first switch, the first voltage source, the second switch, and the second output form a series circuit path;
an IC output to output a first voltage corresponding to the first voltage source when the first and second switches are in the first state for monitoring operation of a signal path from the magnetic sensing element to the IC output;
third and fourth switches coupled to a respective one of the differential first and second outputs;
a second voltage source coupled between the third and fourth switches, the third and fourth switches having a second state in which the second voltage source is coupled across the differential first and second outputs, wherein the first and second voltage sources have different polarities,
wherein the IC output outputs a second voltage corresponding to the second voltage source when the third and fourth switches are in the second state for monitoring operation of a signal path from the magnetic sensing element to the IC output;
a fifth switch coupled between the second differential output of the magnetic field sensing element and the first switch; and
a sixth switch coupled between the first differential output of the magnetic field sensing element and the second switch,
wherein respective states of the first, second, third, and fourth switches is controllable to verify a gain of the signal path.

US Pat. No. 9,929,141

DEVICES WITH AN EMBEDDED ZENER DIODE

Allegro MicroSystems, LLC...

1. A silicon-controlled rectifier (SCR) comprising:a Zener diode;
an n-type region;
a first P+-type region extending into the n-type region;
a first N+-type region extending into the n-type region;
a p-type well extending into the n-type region;
a second N+-type region extending into the p-type well; and
a second P+-type region extending into the p-type well,
wherein the Zener diode is embedded between the first and second N+-type regions and extending through a field oxide layer and into a single doped region, wherein the single doped region is the n-type region.

US Pat. No. 9,922,673

MAGNETORESISTANCE ELEMENT WITH IMPROVED RESPONSE TO MAGNETIC FIELDS

Allegro MicroSystems, LLC...

1. A magnetoresistance element deposited upon a substrate, comprising:
a first synthetic antiferromagnet (SAF) structure, comprising:
a first ferromagnetic layer;
a second ferromagnetic layer; and
a first spacer layer between the first and second ferromagnetic layers of the first synthetic antiferromagnet (SAF) structure,
wherein the first spacer layer is comprised of a selected material with a selected thickness to allow an antiferromagnetic
coupling between the first and second ferromagnetic layers of the first synthetic antiferromagnet (SAF) structure;

a second synthetic antiferromagnet (SAF) structure, comprising:
a third ferromagnetic layer;
a fourth ferromagnetic layer; and
a second spacer layer between the third and fourth ferromagnetic layers of the second synthetic antiferromagnet (SAF) structure,
wherein the second spacer layer is comprised of a selected material with a selected thickness to allow an antiferromagnetic
coupling between the third and fourth ferromagnetic layers of the second synthetic antiferromagnet (SAF) structure;

a first antiferromagnetic layer disposed proximate to and coupled to the first synthetic antiferromagnet (SAF) structure;
a second antiferromagnetic layer disposed proximate to and coupled to the second synthetic antiferromagnet (SAF) structure,
such that the first and second synthetic antiferromagnet (SAF) structures are disposed between the first and second antiferromagnetic
layers, wherein the first and second antiferromagnetic layers are comprised of PtMn, wherein the first antiferromagnetic layer
has a first thickness selected from a first range of thicknesses, and wherein the second antiferromagnetic layer has a second
thickness selected from a second range of thicknesses different than the first range of thicknesses, wherein magnetic field
directions in the first and second synthetic antiferromagnet (SAF) structures are annealed to be ninety degrees apart, wherein
a magnetic field direction in the first antiferromagnetic layer is annealed to be parallel with the magnetic field direction
in the first synthetic antiferromagnet (SAF) structure, and wherein a magnetic field direction in the second antiferromagnetic
layer is annealed to be parallel with the magnetic field direction in the second synthetic antiferromagnet (SAF) structure;

a free layer structure disposed between the first and second synthetic antiferromagnet (SAF) structures;
a first nonmagnetic layer disposed between the first synthetic antiferromagnet (SAF) structure and the free layer structure;
and

a second nonmagnetic layer disposed between the second synthetic antiferromagnet (SAF) structure and the free layer structure,
wherein a material of the first nonmagnetic layer is selected to allow a thickness of the first nonmagnetic layer to be greater
than 0.5 nm while allowing a desired partial pinning between the first synthetic antiferromagnet (SAF) structure and the free
layer structure, wherein the second antiferromagnetic layer is thicker than the first antiferromagnetic layer.

US Pat. No. 9,880,026

MAGNETIC FIELD SENSOR FOR DETECTING MOTION OF AN OBJECT

Allegro MicroSystems, LLC...

1. A magnetic field sensor for detecting motion of an object, comprising:
a magnet configured to generate a magnetic field and having a first surface adjacent to the object and a second surface distal
from the object, wherein the first surface has a centerline axis substantially parallel to and disposed on the first surface,
wherein the centerline axis is substantially diagonal with respect to a motion axis substantially parallel to and disposed
on the first surface, wherein features of the object pass parallel to the motion axis when the object is in motion; and

a semiconductor substrate disposed between the magnet and the object, the semiconductor substrate supporting a plurality of
spaced magnetoresistance elements disposed along a sensing element axis substantially parallel to the centerline axis of the
magnet and configured to generate a respective plurality of magnetic field signals in response to the motion of the object
with respect to the magnetic field, wherein a line substantially perpendicular to the first surface of the magnet intersects
both the centerline axis and the sensing element axis, and wherein each of the plurality of magnetoresistance elements has
a maximum response axis orthogonal to the centerline axis.

US Pat. No. 9,753,098

MAGNETIC SENSOR HAVING ENHANCED LINEARIZATION BY APPLIED FIELD ANGLE ROTATION

ALLEGRO MICROSYSTEMS, LLC...

1. A device, comprising:
a first magnetoresistive magnetic field sensing element positioned with respect to a shaped conductor such that an applied
field generated by current through the shaped conductor forms an offset angle theta defined by the applied field and a field
of a pinning layer of the first magnetoresistive magnetic field sensing element, wherein the offset angle theta is greater
than about five degrees to increase a linearity of an output of the first magnetoresistive magnetic field sensing element
for current in the shaped conductor flowing in a first direction; and

an output module to receive the linearized signal and provide a device output signal.

US Pat. No. 9,620,705

METHODS AND APPARATUS FOR MAGNETIC SENSOR HAVING NON-CONDUCTIVE DIE PADDLE

Allegro MicroSystems, LLC...

1. A magnetic field sensor device, comprising:
a magnetic sensor element;
a die having wafer bumps, wherein the magnetic sensor element is positioned in relation to the die;
a non-conductive die paddle over which the die is disposed;
conductive leadfingers having respective portions electrically connected to the wafer bumps; and
a region about the magnetic sensor element that does not contain electrically conductive leadfinger material for preventing
eddy current flow.

US Pat. No. 10,066,964

MAGNETIC FIELD SENSOR AND ASSOCIATED METHOD THAT CAN SENSE A POSITION OF A MAGNET

Allegro Microsystems, LLC...

1. A magnetic assembly, comprising:a first magnet having north and south magnetic poles;
a second magnet having north and south magnetic poles;
a movable shaft fixedly coupled to the second magnet such that movement of the movable shaft results in movement of the second magnet relative to the first magnet such that a line between centers of the north and south magnetic poles of the second magnet is movable relative to a line between the north and south magnetic poles of the first magnet, wherein an attraction of the second magnet to the first magnet result in a restoring force upon the shaft; and
a magnetic field sensor disposed between the first and second magnets, wherein the magnetic field sensor comprises an electronic circuit, comprising:
a substrate having a major surface disposed in an x-y plane, wherein the line between centers of the north and south magnetic poles of the first magnet is perpendicular to the x-y plane;
first, second, third, and fourth Magnetic field sensing elements disposed upon the major surface of the substrate and configured to generate first, second, third and fourth respective electronic magnetic field signals, wherein each electronic magnetic field signal is responsive to a respective magnetic field parallel to the major surface of the substrate, wherein the first and third magnetic field sensing elements have respective first and third maximum response axes parallel to each other, directed in opposite directions, and parallel the major surface of the substrate, and wherein the second and fourth magnetic field sensing elements have respective second and fourth maximum response axes parallel to each other, directed in opposite directions, and parallel the major surface of the substrate, wherein the first and third major response axes are not parallel to the second add fourth major response axes;
a first differential circuit coupled to the first and third magnetic field sensing elements and configured to generate a first difference signal related to a difference between the first and third electronic magnetic field signals; and
a second differential circuit coupled to the second and fourth magnetic field sensing elements and configured to generate a second difference signal related to a difference between the second and fourth electronic magnetic field signals, wherein the first difference signal has an amplitude related to an x-axis projection upon the x-y plane and the second difference signal has an amplitude related to a y-axis projection upon the x-y plane.

US Pat. No. 10,041,810

ARRANGEMENTS FOR MAGNETIC FIELD SENSORS THAT ACT AS MOVEMENT DETECTORS

Allegro MicroSystems, LLC...

1. A magnetic field sensor for sensing a movement of an object along a path, a movement line tangent to the path, the magnetic field sensor comprisinga magnet, the magnet comprising a north pole, a south pole, and a magnet axis passing through the north pole and the south pole;
a semiconductor substrate proximate to the magnet in a back biased arrangement and at a position between the object and the magnet, the semiconductor substrate having first and second major opposing surfaces, the magnet axis substantially perpendicular to the first opposing surface of the semiconductor substrate, the semiconductor substrate having first and second orthogonal axes on the first opposing surface of the substrate intersecting at a substrate point on the first surface of the substrate, wherein the magnet axis intersects the substrate point, wherein a projection of the movement line onto the first opposing surface of the semiconductor substrate is substantially parallel to the first orthogonal axis on the first surface of the substrate;
a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed along the first or second orthogonal axis, wherein the first magnetic field sensing element comprises an axis of maximum sensitivity substantially perpendicular to the first opposing surface of the substrate;
a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed along the first or second orthogonal axis, wherein the second magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first opposing surface of the substrate, wherein the axis of maximum sensitivity of the second magnetic field sensing element is substantially parallel to the first orthogonal axis, wherein the first magnetic field sensing element is not disposed over or under the second magnetic field sensing element relative to the first surface of the semiconductor substrate;
a first electronic circuit channel coupled to the first magnetic field sensing element, the first electronic circuit channel operable to generate a first signal having a first phase: and
a second electronic circuit channel coupled to the second magnetic field sensing element, the second electronic circuit channel operable to generate a second signal having a second phase approximately +/?ninety degrees apart from the first phase regardless of a speed of the movement of the object, wherein a sign of the ninety degrees is indicative of a direction of the movement of the object.

US Pat. No. 10,012,518

MAGNETIC FIELD SENSOR FOR SENSING A PROXIMITY OF AN OBJECT

Allegro MicroSystems, LLC...

1. A magnetic field sensor for sensing a movement of a ferromagnetic object, the magnetic field sensor comprising:a magnet;
a semiconductor substrate having first and second surfaces, the semiconductor substrate proximate to the magnet and at a position between the ferromagnetic object and the magnet, the semiconductor substrate comprising:
first and second orthogonal axes on the first surface of the substrate intersecting at a coordinate axes point; and
a substrate region upon the first opposing surface of the substrate, the substrate region proximate to and surrounding the coordinate axis point, wherein magnetic fields generated by the magnet within the substrate region are substantially perpendicular to the first and second surfaces of the semiconductor substrate in the absence of the ferromagnetic object, the magnetic field sensor further comprising:
a first magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the substrate region, wherein the first magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the first orthogonal axis, wherein a center of the first magnetic field sensing element is disposed along the first orthogonal axis;
a second magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the semiconductor region, wherein the second magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the axis of maximum sensitivity of the first magnetic field sensing element, and wherein a center of the second magnetic field sensing element is disposed along the first orthogonal axis;
a third magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the semiconductor region, wherein the third magnetic field sensing element comprises an axis of maximum sensitivity substantially perpendicular to the axis of maximum sensitivity of the first magnetic field sensing element and substantially parallel to the first surface of the semiconductor substrate, and wherein a center of the third magnetic field sensing element is disposed along the second orthogonal axis;
a fourth magnetic field sensing element disposed on or under the first surface of the semiconductor substrate and disposed outside of the semiconductor region, wherein the fourth magnetic field sensing element comprises an axis of maximum sensitivity substantially parallel to the axis of maximum sensitivity of the third magnetic field sensing element, wherein a center of the fourth magnetic field sensing element is disposed along the second orthogonal axis, wherein the centers of the first and second magnetic field sensing elements are substantially equidistant from and on opposite sides of the coordinate axes point, and wherein the centers of the third and fourth magnetic field sensing elements are substantially equidistant from and on opposite sides of the coordinate axes point; and
an electronic circuit disposed upon the substrate, configured to combine signals from the first, second, third, and fourth magnetic field sensing elements to generate a combined signal, and configured to compare the combined signal with a threshold signal to generate a two-state binary signal having a change of state when the ferromagnetic object moves closer to the semiconductor substrate than a predetermined distance.

US Pat. No. 9,941,224

MULTI-DIE INTEGRATED CIRCUIT DEVICE WITH CAPACITIVE OVERVOLTAGE PROTECTION

Allegro MicroSystems, LLC...

1. An apparatus comprising: a package;a plurality of external leads extending outside the package;
a first die within the package having one or more first contacts electrically coupled to at least a first one of the external leads;
a second die within the package having one or more second contacts electrically coupled to at least a second one of the external leads; and
a capacitor coupled between the first and second die to allow an electrostatic discharge (ESD) current to flow between the first die and the second die in response to an ESD event and to electrically isolate the first and second die from each other in the absence of the ESD event;
wherein the capacitor is coupled directly one the one or more first and/or the one or more second contacts.

US Pat. No. 10,036,785

TEMPERATURE-COMPENSATED MAGNETO-RESISTIVE SENSOR

Allegro MicroSystems, LLC...

1. An integrated circuit (IC) comprising:a sensor comprising:
a first magnetoresistive (MR) element having a first percentage change in nominal resistance in the presence of a magnetic field; and
a second MR element having a second, different percentage change in nominal resistance in the presence of the magnetic field than the first MR element and comprising a metal layer diffused into other layers of the second MR element.

US Pat. No. 9,976,876

METHODS AND APPARATUS FOR PHASE SELECTION IN RING MAGNET SENSING

ALLEGRO MICROSYSTEMS, LLC...

1. A method, comprising:for a magnetic field sensor IC package having a first channel for a planar magnetic field sensing element and a second channel for a vertical magnetic field sensing element, receiving a desired phase relationship between the first and second channels;
positioning the IC package in relation to an axis of a ring magnet to provide the desired phase relationship between the first and second channels; and
positioning the IC package to a non-zero twist angle with respect to the axis and a non-zero displacement with respect to the axis,
wherein the phase relationship is selected using a mesh function of the offset angle and displacement for the sensor.

US Pat. No. 9,928,194

NON-LINEAR TRANSMIT BIASING FOR A SERIAL BUS TRANSMITTER

Allegro Microsystems, LLC...

1. A transmitter comprising:a controller configured to generate data for transmission by the transmitter over a serial bus coupled to the transmitter; and
a transmit driver coupled to the controller, the transmit driver configured to, in response to the generated data for transmission:
generate low-to-high logic transitions on the serial bus by charging the serial bus by a bus current based on (i) a predetermined initial bias level for a first time period, and (ii) a first predetermined maximum bias level for a second time period; and
generate high-to-low logic transitions on the serial bus by discharging the serial bus by a bus current based on (i) a pre-charged level of the transmit driver, and (ii) a second predetermined maximum bias level for a third time period;
wherein the transmit driver comprises:
an output transistor having an output node coupled to the serial bus, the output transistor configured to:
generate low-to-high logic transitions on the serial bus wherein the controller is configured to (i) set a bias level of the output transistor to the predetermined initial bias level by a first bias current, and (ii) linearly change the bias level from the predetermined initial bias level to a second bias level by a predetermined second bias current, whereby the output transistor is configured to non-linearly charge the output node;
generate high-to-low logic transitions on the serial bus wherein the controller is configured to (i) pre-charge the bias level of the output transistor to a pre-charge bias level by a pre-charge bias current, and (ii) linearly change the bias level from the pre-charge bias level to a fourth bias level, whereby the output transistor is configured to non-linearly discharge the output node.

US Pat. No. 10,074,939

SIGNAL ISOLATOR HAVING INDUCTIVE AND CAPACITIVE SIGNAL COUPLING

Allegro MicroSystems, LLC...

1. A signal isolator, comprising:a first coil having first and second ends;
a first plate coupled to the first end of the first coil;
a second plate coupled to the second end of the first coil, where the first and/or second plate is configured to be coupled to a drive circuit;
a second coil inductively coupled to the first coil;
a third plate capacitively coupled to the first plate;
a fourth plate capacitively coupled to the second plate;
at least one isolation layer between the first and second coils and between the first and second plates and the third and fourth plates;
a receive module including a first receive circuit coupled to the third and fourth plates and a second receive circuit to receive a signal on the second coil; and
a processing module to generate an output signal corresponding to a signal transmitted by the drive circuit from signals received by the first and second receive circuits.

US Pat. No. 10,066,965

MAGNETIC FIELD SENSOR AND ASSOCIATED METHOD THAT CAN ESTABLISH A MEASURED THRESHOLD VALUE AND THAT CAN STORE THE MEASURED THRESHOLD VALUE IN A MEMORY DEVICE

Allegro MicroSystems, LLC...

1. A magnetic field sensor, comprising:a magnetic field sensing element responsive to a changing magnetic field and configured to generate a magnetic field signal having an amplitude;
a measured threshold module configured to generate a measured threshold signal in accordance with positive peaks and negative peaks of the magnetic field signal;
a memory device coupled to receive and configured to store, at each one of a plurality of storage times, a respective value of the measured threshold signal;
a threshold module coupled to receive from the memory device, at a calculation time, a stored value of the measured threshold signal stored at a selected one of the plurality of storage times prior to the calculation time and configured to process the received stored value of the measured threshold signal to generate a calculated threshold value; and
a comparison circuit coupled to receive the calculated threshold value and also coupled to receive a signal representative of the magnetic field signal, wherein the comparison circuit is configured to compare the calculated threshold value with a signal representative of the magnetic field signal to generate an output signal.

US Pat. No. 10,050,193

MAGNETORESISTANCE STRUCTURE PATTERNING

Allegro MicroSystems, LLC...

1. A method, comprising:depositing on a substrate a magnetoresistance stack comprising a plurality of layers comprising a first set of one or more magnetoresistance layers and a second set of one or more magnetoresistance layers;
depositing a hard mask on the magnetoresistance stack;
depositing photoresist on the hard mask;
patterning the photoresist using photolithography to expose portions of the hard mask;
etching the exposed portions of the hard mask to expose a portion of the magnetoresistance stack;
stripping the photoresist;
etching the first set of one or more magnetoresistance layers of the exposed portion of the magnetoresistance stack to form an intermediate structure comprising the hard mask and the first set of one or more magnetoresistance layers;
depositing an etch barrier on the intermediate structure and the second set of one or more magnetoresistance layers;
etching the etch barrier and a portion of the second set of one or more magnetoresistance layers to the substrate to form a pillar structure comprising side walls comprising the etch barrier, the side walls disposed on the second set of one or more magnetoresistance layers; and
depositing an endcap comprising silicon nitride on the pillar structure.