US Pat. No. 9,787,175

HIGH VOLTAGE POWER CONVERTER WITH A CONFIGURABLE INPUT

ASTEC INTERNATIONAL LIMIT...

1. A high voltage power converter comprising:
first, second, and third switches for receiving an alternating-current (AC) input;
a control power factor correction (PFC) rail connected to each of the first, second, and third switches for receiving the
AC input, the control PFC rail including a control power stage having an inductor;

a slave PFC rail connected to each of the first, second, and third switches for receiving the AC input and providing an output
substantially identical to an output of the control PFC rail, the slave PFC rail including a slave power stage having an inductor;

wherein the first, second, and third switches are configurable to adapt the high voltage power converter for operating in
a first inclusive input voltage range between 170 VAC and 265 VAC and a second inclusive input voltage range between 340 VAC
and 530 VAC;

wherein the inductor of the control power stage and the inductor of the slave power stage have a common core;
wherein the control PFC rail output and the slave PFC rail output are each connected to an output stage; and
wherein the output stage is for connection to a load.

US Pat. No. 9,240,724

MULTIPHASE DC/DC CONVERTERS AND CONTROL CIRCUITS FOR CONTROLLING CONVERTERS USING FIXED AND/OR VARIABLE FREQUENCIES

ASTEC INTERNATIONAL LIMIT...

1. A multiphase DC/DC power converter comprising an input, an output, at least a first converter and a second converter coupled
in parallel between the input and the output, an inductor coupled to the first and second converters, an output capacitor
coupled between the output and a reference potential, and a control circuit coupled to the first converter and the second
converter, the first and second converters each including a power switch, the control circuit configured to switch the power
switches at a fixed frequency with substantially no phase shift therebetween during startup of the multiphase DC/DC power
converter, and to switch the power switches at a variable frequency with a defined phase shift therebetween after startup
of the multiphase DC/DC power converter to vary a gain of the multiphase DC/DC power converter and regulate a voltage at the
output.

US Pat. No. 9,203,296

POWER SUPPLY SYSTEMS WITH FILTERS

ASTEC INTERNATIONAL LIMIT...

9. A system comprising:
a power supply including an input; and
an input filter having at least two inputs, at least two outputs, a pair of X-capacitors including a first X-capacitor and
a second X-capacitor, and a common mode choke coupled between the at least two inputs and the at least two outputs, each input
of the input filter including a pair of input terminals, each output including a pair of output terminals, each X-capacitor
having a first terminal and a second terminal, the first terminal of the first X-capacitor coupled between one input terminal
of the pair of input terminals of one of the at least two inputs and one output terminal of the pair of output terminals of
one of the at least two outputs, the second terminal of the first X-capacitor coupled between one input terminal of the pair
of input terminals of another one of the at least two inputs and one output terminal of the pair of output terminals of another
one of the at least two outputs, the first terminal of the second X-capacitor coupled between another input terminal of the
pair of input terminals of said one of the at least two inputs and another output terminal of the pair of output terminals
of said one of the at least two outputs, the second terminal of the second X-capacitor coupled between another input terminal
of the pair of input terminals of said another one of the at least two inputs and another output terminal of the pair of output
terminals of said another one of the at least two outputs, the common mode choke including a magnetic core and at least four
windings extending about the magnetic core, each winding coupled between a different one of the pair of input terminals of
each of the at least two inputs and a different one of the pair of output terminals of each of the at least two outputs than
the other windings of the common mode choke of the input filter, at least one of the at least two outputs of the input filter
coupled to the input of the power supply.

US Pat. No. 9,065,323

SYSTEMS AND METHODS FOR DETECTING ISLANDING CONDITIONS IN GRID-TIED INVERTERS

ASTEC INTERNATIONAL LIMIT...

1. A grid-tie inverter comprising:
a power circuit having an input terminal for coupling to a DC power source and an output terminal for coupling to an AC power
grid; and

a control circuit coupled to the power circuit, the control circuit configured to perturb an AC output current of the power
circuit a first time and detect a first change in an AC output voltage of the power circuit without shutting down the power
circuit, perturb the AC output current of the power circuit a second time and detect a second change in the AC output voltage
of the power circuit, and shut down the power circuit in response to detecting at least the first change in the AC output
voltage and the second change in the AC output voltage, wherein the AC output current is perturbed such that the AC output
current is decreased and increased in substantially equal magnitudes at least one of the first time and the second time, and
wherein the control circuit is further configured to add a current delta after the AC output current is perturbed at least
one of the first time and the second time such that the AC output current is decreased and increased in substantially equal
magnitudes corresponding to the change in magnitude in the opposite direction when the AC output current is perturbed.

US Pat. No. 9,431,900

DYNAMIC OPERATING FREQUENCY CONTROL OF A BUCK POWER CONVERTER HAVING A VARIABLE VOLTAGE OUTPUT

ASTEC INTERNATIONAL LIMIT...

1. A switch controller for a power converter having a variable output voltage range comprising:
a pulse width modulator having an output producing a pulsed signal for driving a power converter switch;
a mode selector having an output indicative of an operating on-time state of the power converter connected to a multiplier;
a period selector having an output indicative of a cycle time for the pulsed signal connected to the multiplier and to an
input of the pulse width modulator;

the multiplier having an output indicative of a switch on-time of the cycle time connected to another input of the pulse width
modulator;

a comparator having an output indicative of the operating on-time state relative to a minimum operating on-time and connected
to an input of the period selector; and

wherein the period selector outputs a nominal cycle time to the pulse width modulator when the operating on-time state is
greater than the minimum operating on-time and wherein the period selector outputs an updated cycle time greater than the
nominal cycle time when the operating on-time state is less than the minimum operating on-time such that the pulse width modulator
outputs a pulsed signal with the updated cycle time and a duty cycle equal to a duty cycle of an immediately preceding pulsed
signal.

US Pat. No. 9,065,325

CONTROL CIRCUITS FOR POWER CONVERTERS

ASTEC INTERNATIONAL LIMIT...

1. A control circuit for controlling one or more power switches of a power converter coupled to a load, the control circuit
comprising:
a voltage control loop configured to update a parameter of the voltage control loop at a first frequency,
a current control loop; and
a detector for detecting a transient load condition;
the control circuit configured to generate a current reference for the current control loop using an AC reference signal and
(a) the voltage control loop parameter updated at the first frequency when the transient load condition is detected, and (b)
the voltage control loop parameter sampled at a second frequency lower than the first frequency and no more than twice per
full cycle of the AC reference signal when the transient load condition is not detected.

US Pat. No. 9,571,091

METHODS FOR OVERDRIVING A BASE CURRENT OF AN EMITTER SWITCHED BIPOLAR JUNCTION TRANSISTOR AND CORRESPONDING CIRCUITS

ASTEC INTERNATIONAL LIMIT...

1. A method of overdriving a base current of an emitter switched bipolar junction transistor (BJT) having a base, a collector
and an emitter, the method comprising:
supplying a first current and a second current to the base of the BJT, the emitter of the BJT coupled to a metal oxide semiconductor
field effect transistor;

monitoring a voltage at the collector; and
turning off the second current in response to the monitored voltage of the collector decreasing to a voltage threshold indicating
the BJT is substantially saturated.

US Pat. No. 9,124,180

MULTIPLE RESONANT CONVERTER APPARATUS AND CONTROL METHOD

ASTEC INTERNATIONAL LIMIT...

1. A resonant converter apparatus comprising:
a plurality of resonant converters connected in parallel; and
a control module configured to output a pulse width modulation (PWM) control signal to the plurality of resonant converters,
wherein:

the control module comprises a voltage control loop and a current control loop;
a voltage sensing end of the control module is configured to receive a sensed output voltage of the plurality of resonant
converters;

a current sensing end of the control module is configured to receive a sensed output current of each of the plurality of resonant
converters;

the voltage control loop of the control module is configured to compare the sensed output voltage with a predetermined reference
voltage, and output a PWM control signal to one resonant converter of the plurality of resonant converters according to a
voltage comparison result so that an output voltage of the one resonant converter is equal to the predetermined reference
voltage; and

the current control loop of the control module is configured to use the sensed output current of the one resonant converter
as a reference current, compare the reference current with the sensed output current received from each of the plurality of
resonant converters other than the one resonant converter, generate a frequency adjusting variable of the PWM control signal
for each of the plurality of resonant converters other than the one resonant converter based on the current comparison result,
and calculate the PWM control signal for each of the plurality of resonant converters other than the one resonant converter
based on the PWM control signal provided to the one resonant converter and the frequency adjusting variable to adjust the
output current of each of the plurality of resonant converters other than the one resonant converter to be equal to the output
current of the one resonant converter.

US Pat. No. 9,165,707

MULTIPHASE POWER CONVERTERS HAVING SHARED MAGNETIC CORE SECTIONS

Astec International Limit...

1. A multiphase power converter comprising:
a plurality of subconverters, each subconverter having an input circuit, an output circuit, and a magnetic core coupling the
input circuit to the output circuit, the magnetic core of at least one of the plurality of subconverters having a core section
that is shared by the magnetic core of another one of the plurality of subconverters; and

a control circuit configured to operate the input circuits of the plurality of subconverters with different phases.

US Pat. No. 9,219,413

POWER SUPPLIES RESPONSIVE TO MULTIPLE CONTROL SIGNAL FORMATS

ASTEC INTERNATIONAL LIMIT...

1. A power supply having a power circuit for converting an input voltage or current to an output voltage or current, an electrical
terminal for receiving signals from one or more external devices, and a control circuit coupled to the power circuit and the
electrical terminal, the control circuit being configurable while the power supply is operating to operate the power circuit
in response to control signals having a selected one of a plurality of different control signal formats that are received
by said electrical terminal, and the control circuit being reconfigurable while the power supply is operating to operate the
power circuit in response to control signals having another selected one of the plurality of different control signal formats
that are received by said electrical terminal.

US Pat. No. 9,866,134

CONTROL CIRCUITS AND METHODS FOR REGULATING OUTPUT VOLTAGES USING MULTIPLE AND/OR ADJUSTABLE REFERENCE VOLTAGES

ASTEC INTERNATIONAL LIMIT...

1. A method of regulating an output voltage of a switched mode power supply having a variable input voltage and at least one
power switch, the method comprising:
generating a control signal for the at least one power switch using a reference voltage, the control signal having a duty
cycle;

determining if a temperature within the switched mode power supply is above a threshold temperature; and
in response to determining the temperature is above the threshold temperature, adjusting the reference voltage to adjust the
duty cycle of the control signal for the at least one power switch of the switched mode power supply.

US Pat. No. 9,450,496

MULTI-STAGE POWER CONVERTERS AND METHODS FOR VARYING A REGULATED VOLTAGE OF ONE STAGE AS A FUNCTION OF AN OUTPUT CURRENT OF ANOTHER STAGE

ASTEC INTERNATIONAL LIMIT...

1. A multi-stage power converter comprising:
a pre-regulator circuit configured to provide a regulated output voltage, the pre-regulator circuit including one or more
power switches;

at least one LLC resonant converter configured to provide an output voltage and an output current to a load, the LLC resonant
converter including an input, an output, one or more resonant elements, and at least one power switch, the input of the LLC
resonant converter coupled to the pre-regulator circuit; and

a control circuit coupled to the pre-regulator circuit and the LLC resonant converter, the control circuit including an error
amplifier and a voltage controlled oscillator, the error amplifier configured to produce an output signal that is provided
directly to the voltage controlled oscillator, the voltage controlled oscillator configured to provide a control signal to
control the at least one power switch of the LLC resonant converter to regulate the output voltage of the LLC resonant converter
and provide a variable reference signal representing a switching frequency of the at least one power switch of the LLC resonant
converter to control the one or more power switches of the pre-regulator circuit to vary the regulated output voltage of the
pre-regulator circuit as a function of the output current of the LLC resonant converter.

US Pat. No. 9,163,849

JITTER CONTROL AND OPERATING PROFILES FOR AIR MOVING DEVICES

Astec International Limit...

1. An electronic system comprising:
an air moving device; and
a controller for controlling the air moving device, the controller configured to selectively control a rotational speed of
the air moving device by determining a target rotational speed and a range of rotational speeds based at least in part on
a temperature of the electronic system, the range including the target rotational speed and bounded by and including a first
rotational speed and a second rotational speed, and varying the rotational speed around the target rotational speed and within
the range by increasing the rotational speed of the air moving device above the target rotational speed and decreasing the
rotational speed of the air moving device below the target rotational speed during a time that the temperature of the electronic
system and the target rotational speed are fixed to reduce acoustic tones generated by the air moving device, wherein varying
the rotational speed around the target rotational speed includes cycling the rotational speed by sweeping the rotational speed
from the first rotational speed to the second rotational speed, and from the second rotational speed to the first rotational
speed, during normal cooling operation.

US Pat. No. 9,748,948

METHODS FOR OVERDRIVING A BASE CURRENT OF AN EMITTER SWITCHED BIPOLAR JUNCTION TRANSISTOR AND CORRESPONDING CIRCUITS

ASTEC INTERNATIONAL LIMIT...

1. A power converter control circuit comprising:
a bipolar junction transistor (BJT) having a base, a collector and an emitter;
a metal oxide semiconductor field effect transistor (MOSFET) coupled to the emitter;
a bias voltage supply coupled to the base;
a buffer coupled to the base;
a controller coupled to the gate of the MOSFET, the controller configured to apply a pulse width modulated (PWM) signal to
control the MOSFET; and

a timer element coupled between the controller and an input of the buffer, the timer element configured to, in response to
receiving a control signal from the controller to turn on the MOSFET, cause the buffer to inject a current pulse to the base
for a fixed period of time, the fixed period of time selected such that the current pulse will substantially saturate the
BJT.

US Pat. No. 9,706,638

ASSEMBLIES AND METHODS FOR DIRECTLY CONNECTING INTEGRATED CIRCUITS TO ELECTRICALLY CONDUCTIVE SHEETS

ASTEC INTERNATIONAL LIMIT...

1. An integrated circuit assembly comprising:
an integrated circuit;
a first electrically conductive sheet formed separately from the integrated circuit;
a second electrically conductive sheet electrically isolated from the first electrically conductive sheet and formed separately
from the integrated circuit;

a non-conductive material disposed between the first and second electrically conductive sheets and formed separately from
the integrated circuit, the non-conductive material separating and electrically isolating the first electrically conductive
sheet from the second electrically conductive sheet;

an electrical trace disposed on the non-conductive material and electrically isolated from the first and second electrically
conductive sheets, the electrical trace including a conductive via formed in at least the non-conductive material;

the integrated circuit having a top side and a bottom side, the integrated circuit positioned on a first side of the electrically
conductive sheets and having at least one lead directly connected to the first electrically conductive sheet on the bottom
side of the integrated circuit, at least one lead directly connected to the second electrically conductive sheet on the bottom
side of the integrated circuit, and at least one lead electrically connected to the electrical trace on the bottom side of
the integrated circuit;

a circuit board positioned on a second side of the electrically conductive sheets; and
at least one control circuit disposed on the circuit board and electrically connected to the conductive via for providing
a control signal to the integrated circuit.

US Pat. No. 9,189,040

SINGLE PHASE REDUNDANT POWER SUPPLIES FOR REDUCING PHASE CURRENT IMBALANCES

Astec International Limit...

1. A single phase AC/DC power supply having a first input for receiving a first AC phase voltage in a polyphase AC power distribution
system, a first output for supplying an amount of DC power to a load, a power circuit coupled between the first input and
the first output, and a control circuit for controlling the power circuit, the control circuit configured to substantially
eliminate AC phase current imbalances in the polyphase AC power distribution system by adjusting the amount of DC power supplied
to the load via the first output and an amount of DC power supplied to the load by at least one other power supply having
a second input coupled to a second phase voltage in the polyphase AC power distribution system and a second output coupled
in parallel with the first output so the amount of DC power supplied to the load by the single phase AC/DC power supply is
different than the amount of DC power supplied to the load by said at least one other power supply when the single phase AC/DC
power supply and said at least one other power supply are so coupled to each other and the load and when a number of power
supplies per phase of the polyphase AC power distribution system is the same.

US Pat. No. 9,748,830

CONTROL CIRCUITS USING DIFFERENT MASTER-SLAVE CURRENT SHARING MODES

ASTEC INTERNATIONAL LIMIT...

1. A power supply for supplying a regulated output voltage, the power supply comprising:
two power converters each including an output coupled in parallel with each other, the two power converters controllable in
a master-slave current sharing relationship, and

a control circuit coupled to the two power converters, the control circuit adapted to detect a presence of a dynamic load
condition of a load coupled to the power supply, control the two power converters in a default master-slave current sharing
mode based on a current sharing correction function, and in response to detecting the presence of the dynamic load condition,
disable the current sharing correction function so that the two power converters are controlled in a modified master-slave
current sharing mode to substantially prevent oscillation between output currents of the two power converters.

US Pat. No. 9,705,405

POWER CONVERTERS AND METHODS FOR REDUCING VOLTAGE CHANGES AT AN OUTPUT OF A POWER CONVERTER

ASTEC INTERNATIONAL LIMIT...

1. A switching power converter comprising:
an input for receiving an input voltage from a power source;
an output for providing an output voltage to a load;
at least one switch capable of causing a voltage overshoot of the output voltage when the switch is turned on; and
a controller coupled to the at least one switch, the controller configured to sense the output voltage, compare the sensed
output voltage to a voltage reference, and adjust operation of the power converter based on the comparison of the sensed output
voltage and the voltage reference to maintain the output voltage at a target value, the controller further configured to decrease
the voltage reference from a normal operation value to an overshoot reduction value before turning on the switch to decrease
the output voltage and reduce an overshoot of the output voltage in response to turning on the switch.

US Pat. No. 9,621,020

CONTROL CIRCUITS AND METHODS FOR CONTROLLING SWITCHING DEVICES

ASTEC INTERNATIONAL LIMIT...

1. A control circuit for controlling a rectifier having a first terminal, a second terminal, and a control terminal, the control
circuit comprising a first diode for coupling to the first terminal of the rectifier, a second diode for coupling to the second
terminal of the rectifier, a first transistor for coupling to the control terminal of the rectifier, a second transistor coupled
to the second diode, and a third diode coupled between a first terminal of the first transistor and a second terminal of the
first transistor to limit saturation of the first transistor, the first transistor coupled to the first diode, the control
circuit configured to allow current flow in only one direction between the first and second terminals of the rectifier.

US Pat. No. 9,559,516

ARC PREVENTION IN DC POWER SYSTEMS

ASTEC INTERNATIONAL LIMIT...

1. A power system comprising:
a DC power source having a maximum output voltage;
a DC/AC inverter having an input coupled via a connection to the DC power source and an output for supplying AC power to a
load; and

a control circuit for controlling the DC/AC inverter, the control circuit configured to maintain a DC voltage at the input
of the DC/AC inverter above a threshold voltage by controlling an amount of current drawn by the DC/AC inverter from the DC
power source to inhibit arcing as a result of a break in the connection between the DC power source and the DC/AC inverter;

wherein the threshold voltage is substantially equal to the maximum output voltage of the DC power source less a minimum arcing
voltage for the connection between the DC power source and the DC/AC inverter.

US Pat. No. 9,698,694

CONTROL CIRCUITS AND METHODS FOR REGULATING OUTPUT VOLTAGES BASED ON ADJUSTABLE REFERENCES VOLTAGES

ASTEC INTERNATIONAL LIMIT...

1. A control circuit for regulating an output voltage of a switched mode power supply having a variable input voltage and
at least one power switch, the control circuit operable to generate a comparison voltage based on the output voltage of the
switched mode power supply and an adjustable duty cycle of a control signal provided to the at least one power switch; determine
a constant reference voltage based on whether the generated comparison voltage falls within one of a plurality of voltage
ranges, each voltage range associated with a different constant reference voltage; and adjust the duty cycle of the control
signal provided to the at least one power switch of the switched mode power supply as a function of the determined constant
reference voltage and the output voltage.

US Pat. No. 10,063,140

CONTROL CIRCUITS FOR SELECTIVELY APPLYING ERROR OFFSETS TO IMPROVE DYNAMIC RESPONSE IN SWITCHING POWER CONVERTERS

ASTEC INTERNATIONAL LIMIT...

1. A control circuit for controlling a power circuit having an input, an output for providing an output current, and at least one power switch coupled between the input and the output, the control circuit comprising:a control loop configured to generate a control signal for the at least one power switch of the power circuit based on an error signal determined by comparing a sensed parameter of the power circuit and a reference signal, and
a positive offset signal and a negative offset signal each configured to adjust the control signal, the control circuit configured to detect a change in the output current and selectively apply only one of the positive offset signal and the negative offset signal based on the change in the output current of the power circuit to adjust the control signal thereby enhancing a dynamic response to the change in the output current, the control circuit configured to remove said one of the positive offset signal and the negative offset signal applied to adjust the control signal after a defined period of time.

US Pat. No. 9,712,080

REDUCING PHASE CURRENT IMBALANCES IN SINGLE PHASE REDUNDANT POWER SUPPLY SYSTEMS WITH UNBALANCED LOADS

ASTEC INTERNATIONAL LIMIT...

1. A system comprising:
a first plurality of power supplies each having an input for coupling to a first AC phase voltage in a polyphase AC power
distribution system, an output for supplying DC current to a load, and an output current sharing parameter for balancing DC
currents;

a second plurality of power supplies each having an input for coupling to a second AC phase voltage in the polyphase AC power
distribution system and an output for supplying DC current to the load;

the outputs of the first plurality of power supplies and the outputs of the second plurality of power supplies electrically
connected in parallel for supplying a substantially constant voltage to the load; and

a controller;
wherein the controller is coupled to at least the first plurality of power supplies;
wherein the first plurality of power supplies and the second plurality of power supplies are single phase AC/DC power supplies;
and

wherein the controller is configured to adjust the output current sharing parameter of at least one of the first plurality
of power supplies to adjust the DC current supplied to the load by said at least one of the first plurality of power supplies
so that the DC current supplied to the load from the first plurality of power supplies is different than the DC current supplied
to the load from the second plurality of power supplies, and wherein the DC current supplied to the load by said at least
one of the first plurality of power supplies is adjusted based on a sensed AC input of the first plurality of power supplies
or the second plurality of power supplies by an amount necessary to avoid or reduce AC phase current imbalances in the polyphase
AC power distribution system.

US Pat. No. 9,906,135

MULTIPHASE DC/DC CONVERTERS AND CONTROL CIRCUITS FOR CONTROLLING CONVERTERS USING FIXED AND/OR VARIABLE FREQUENCIES

Astec International Limit...

1. A multiphase DC/DC power converter comprising an input, an output, at least a first converter and a second converter coupled
in parallel between the input and the output, an inductor coupled to the first and second converters, an output capacitor
coupled between the output and a reference potential, and a control circuit coupled to the first converter and the second
converter, the first and second converters each including a transformer having a primary winding and a secondary winding,
at least one inductor coupled between the input and the primary winding, at least one capacitor coupled between the input
and the primary winding, and a power switch coupled between the input and the primary winding, the first and second converters
each configured to provide a current to the inductor coupled to the first and second converters, a sum of the current from
the first converter and the current from the second converter being substantially constant, the control circuit configured
to switch the power switches at a frequency with a phase shift therebetween, and to vary the frequency of the power switches
to vary a gain of the multiphase DC/DC power converter and regulate a voltage at the output.

US Pat. No. 9,806,519

INPUT REDUNDANT CIRCUIT

ASTEC INTERNATIONAL LIMIT...

1. An input redundant circuit, comprising:
a core power supply;
a first input port for receiving a first input voltage;
a second input port for receiving a second input voltage;
a relay connected to the first input port and the second input port to selectively connect and disconnect the first input
voltage and the second input voltage to the core power supply;

a boosting circuit to boost one of the first input voltage and the second input voltage connected by the relay;
a control circuit configured to disable the boosting circuit before the relay disconnects one of the first input voltage and
the second input voltage from the core power supply; and

a surge current limiting circuit coupled to the core power supply, and configured to limit a surge current generated when
the relay is switched between the first input voltage and the second input voltage.

US Pat. No. 9,906,150

OPEN LOOP BI-DIRECTIONAL CONVERTERS AND CORRESPONDING CONTROL METHODS

ASTEC INTERNATIONAL LIMIT...

1. An open loop bi-directional converter comprising:
an input terminal for receiving an input voltage;
an output terminal for providing an output voltage to a load;
a transformer coupled between the input terminal and the output terminal, the transformer having a primary side and a secondary
side;

one or more primary switches coupled between the input terminal and the primary side of the transformer;
one or more secondary switches coupled between the output terminal and the secondary side of the transformer;
an input capacitor coupled to the input terminal;
an output capacitor coupled to the output terminal; and
a primary side controller coupled to the one or more primary switches, the primary side controller operable to control the
one or more primary switches in an open loop mode at a fixed frequency and a fixed duty cycle;

wherein the open loop bi-directional converter is coupled to provide current from the primary side of the transformer to the
secondary side of the transformer when a voltage of the input capacitor is greater than a voltage of the output capacitor,
and the open loop bi-directional converter is coupled to automatically provide current from the secondary side of the transformer
to the primary side of the transformer when the voltage of the input capacitor is reduced below the voltage of the output
capacitor.

US Pat. No. 9,906,121

CONTROL CIRCUITS AND METHODS FOR TRANSITIONING BETWEEN POWER CONVERTER CONTROL MODES

ASTEC INTERNATIONAL LIMIT...

1. A control circuit for controlling a power converter to operate in a first mode and a second mode different than the first
mode, the control circuit comprising a first integrator circuit corresponding to the first mode and having an output and a
second integrator circuit corresponding to the second mode and having an output, the control circuit configured to transition
control of the power converter between the first mode and the second mode such that one of the first mode and the second mode
is a controlling mode for a period of time and the other one of the first mode and the second mode is a non-controlling mode
for the period of time, and set the output of the first integrator circuit or the second integrator circuit corresponding
to the non-controlling mode to equal the output of the first integrator circuit or the second integrator circuit corresponding
to the controlling mode.

US Pat. No. 9,866,133

CONTROL CIRCUITS AND METHODS FOR REGULATING OUTPUT VOLTAGES USING MULTIPLE AND/OR ADJUSTABLE REFERENCE VOLTAGES

ASTEC INTERNATIONAL LIMIT...

1. A method of regulating an output voltage of a switched mode power supply having a variable input voltage and at least one
power switch, the method comprising:
determining the input voltage;
selecting a reference voltage from a plurality of reference voltages based on the determined input voltage; and
generating a control signal for the at least one power switch of the switched mode power supply as a function of the selected
reference voltage to adjust a duty cycle of the control signal for the at least one power switch of the switched mode power
supply.

US Pat. No. 10,027,220

INTERLEAVED POWER SUPPLIES AND CORRESPONDING CONTROL METHODS

ASTEC INTERNATIONAL LIMIT...

1. An interleaved power supply comprising:an input terminal adapted to receive an input voltage;
an output terminal adapted to provide an output current to a load;
a first phase circuit coupled between the input terminal and the output terminal, the first phase circuit including a first inductor and a first switch coupled to the first inductor;
a second phase circuit coupled between the input terminal and the output terminal, the second phase circuit including a second inductor and a second switch coupled to the second inductor;
at least one current sensor coupled to the output terminal to sense the output current; and
a controller coupled to the current sensor, the first switch and the second switch, the controller operable to control the first phase circuit and the second phase circuit in an interleaved mode when the sensed output current is below a current threshold and to control the first phase circuit and the second phase circuit in an in-phase mode when the sensed output current is above the current threshold.

US Pat. No. 9,991,799

SWITCH MODE POWER SUPPLIES INCLUDING PRIMARY SIDE CLAMPING CIRCUITS CONTROLLED BASED ON SECONDARY SIDE SIGNALS

Astec International Limit...

1. A switch mode power supply comprising:an input to receive an input voltage;
an output to provide an output voltage;
a power converter coupled between the input and the output, the power converter including a transformer having a primary side and a secondary side, and a clamping circuit, the transformer isolating the input from the output, the clamping circuit having at least one first switching device coupled between the transformer and the input;
a second switching device coupled between the transformer and the output; and
a control circuit coupled to the first switching device of the clamping circuit and the second switching device, the control circuit including at least one isolation component and a switch driver, the control circuit configured to control the second switching device with a signal from the switch driver, pass the signal from the switch driver to the primary side of the transformer via the at least one isolation component, and control the first switching device coupled between the transformer and the input in response to the signal received from the switch driver via the at least one isolation component.

US Pat. No. 9,891,679

SINGLE PHASE REDUNDANT POWER SUPPLY SYSTEMS FOR REDUCING PHASE CURRENT IMBALANCES

ASTEC INTERNATIONAL LIMIT...

1. A system comprising:
a first AC/DC power supply having an input coupled to a first phase voltage in a polyphase power distribution system, and
an output coupled to a load for supplying an amount of DC power to the load;

a second AC/DC power supply having an input for coupling to a second phase voltage in the polyphase power distribution system,
and an output coupled to the load for supplying an amount of DC power to the load; and

a controller for controlling one of the first AC/DC power supply and the second AC/DC power supply;
wherein the output of the first AC/DC power supply is coupled in parallel with the output of the second AC/DC power supply;
and

wherein the controller is configured to reduce phase current imbalances in the polyphase power distribution system by adjusting
the amount of DC power supplied to the load by the first AC/DC power supply and the amount of DC power supplied to the load
by the second AC/DC power supply so the amount of DC power supplied to the load by the first AC/DC power supply is different
than the amount of DC power supplied to the load by the second AC/DC power supply when the number of power supplies per phase
of the polyphase power distribution system is the same.

US Pat. No. 9,960,665

POWER SUPPLIES HAVING A SINGLE ISOLATION DEVICE FOR FEEDBACK AND FAULT DETECTION

ASTEC INTERNATIONAL LIMIT...

1. An isolated power supply comprising:a transformer having a primary winding and a secondary winding;
at least one power switch coupled to the primary winding of the transformer;
a controller coupled to the power switch to control operation of the power switch;
an output terminal coupled to the secondary winding to provide an output voltage to a load;
a feedback circuit coupled to the output terminal and adapted to sense the output voltage and compare the sensed output voltage to a voltage reference to define a feedback signal;
a fault detection circuit coupled between the output terminal and the feedback circuit and adapted to sense the output voltage, compare the sensed output voltage to a fault reference, and modify the feedback signal when the sensed output voltage exceeds the fault reference; and
a single isolation device coupled between the feedback circuit and the controller and adapted to provide the feedback signal to the controller, the controller operable to control the power switch based on the feedback signal and to detect a fault condition when a slew rate of the feedback signal exceeds a fault threshold slew rate value.

US Pat. No. 9,979,307

CONTROL CIRCUITS AND METHODS FOR REGULATING OUTPUT VOLTAGES USING MULTIPLE AND/OR ADJUSTABLE REFERENCE VOLTAGES

ASTEC INTERNATIONAL LIMIT...

1. A method of regulating an output voltage of a switched mode power supply having a variable input voltage and at least one power switch, the method comprising:generating a control signal for the at least one power switch of said switched mode power supply using a reference voltage, the control signal having a duty cycle;
determining if the duty cycle of the control signal is within a defined range; and
in response to determining the duty cycle of the control signal is outside the defined range, adjusting the reference voltage to adjust the duty cycle of the control signal for the at least one power switch of the switched mode power supply.

US Pat. No. 10,122,207

AUTOMATIC TRANSFER SWITCH CIRCUITS AND CONTROL METHODS

Astec International Limit...

1. An automatic transfer switch circuit comprising:a first voltage input having a line terminal and a neutral terminal;
a second voltage input having a line terminal and a neutral terminal;
a voltage output having a line output terminal and a neutral output terminal;
a first relay coupled to the line terminal of the first voltage input and the line terminal of the second voltage input;
a second relay coupled to the neutral terminal of the first voltage input and the neutral terminal of the second voltage input;
a third relay coupled between the line output terminal and at least one of the first relay and second relay;
a fourth relay coupled between the neutral output terminal and at least one of the first relay and the second relay; and
a controller coupled to the relays to control a state of each of the relays.

US Pat. No. 10,014,771

SWITCHING SHUNT REGULATOR CIRCUITS

ASTEC INTERNATIONAL LIMIT...

1. A switching shunt regulator circuit comprising:a current source having an input for receiving an input voltage, an output for providing a DC current to a DC load, a buffer, an inductor and an emitter switched bipolar transistor (ESBT) switch including a bipolar junction transistor (BJT) coupled in series with a metal oxide semiconductor field effect transistor (MOSFET), a base of the BJT arranged to be driven by a current drawn from the output, only the MOSFET arranged to be driven by an output of the buffer, the buffer coupled to receive a bias supply voltage derived from a voltage at the output; and
a shunt voltage regulator coupled to the output of the current source;
wherein the buffer is configured to control the MOSFET to operate the inductor in a boundary mode to cycle a current through the inductor between about zero and an upper threshold;
wherein the current source is configured to provide DC current to the DC load and DC current to the shunt voltage regulator when the DC load is coupled to the output, the DC current to the shunt voltage regulator regulating a voltage at the output of the current source; and
wherein the shunt voltage regulator has a current carrying capacity greater than the sum of the DC current to the DC load and the DC current to the shunt voltage regulator.

US Pat. No. 9,973,098

FIXED FREQUENCY DISCONTINUOUS CONDUCTION MODE FLYBACK POWER CONVERTERS EMPLOYING ZERO VOLTAGE SWITCHING

ASTEC INTERNATIONAL LIMIT...

1. A power supply system for supplying power to a load, the power supply system comprising:a flyback power converter including an input for receiving an input voltage, an output for supplying an output voltage, a transformer having a plurality of windings coupled between the input and the output, a first power switch coupled to the transformer, and a clamping circuit having a capacitor, a diode, and a second power switch coupled to one of the plurality of windings, the capacitor and the diode of the clamping circuit coupled in parallel between said one of the plurality of windings and the second power switch; and
a control circuit coupled to the flyback power converter, the control circuit configured to operate the flyback power converter in a discontinuous conduction mode and control the first power switch and the second power switch at a fixed frequency to allow an effective capacitance across the first power switch to discharge to said one of the plurality of windings to cause a voltage across the first power switch to decrease to substantially zero to achieve substantially zero voltage switching during turn on of the first power switch.

US Pat. No. 10,218,284

DC-DC POWER CONVERTERS INCLUDING A VALLEY SKIPPING MODE AND METHODS OF OPERATING DC-DC POWER CONVERTERS

Astec International Limit...

1. An isolated DC-DC flyback power converter, comprising:an input for receiving a DC input voltage from a voltage source;
an output for supplying a DC output voltage to a load;
a transformer coupled between the input and the output, the transformer having a primary winding and a secondary winding;
a primary field-effect transistor (FET) coupled to selectively conduct current through the primary winding of the transformer, the primary FET including a drain that experiences multiple resonant voltage valleys during each dead-time period of the converter;
a synchronous rectifier coupled to selectively conduct current through the secondary winding of the transformer; and
a control circuit configured to operate the primary FET in a valley skipping mode by turning on the primary FET during a second or subsequent one of the multiple resonant voltage valleys during each dead-time period of the converter, and to allow a negative current in the secondary winding of the transformer before turning off the synchronous rectifier during one or more of the multiple resonant voltage valleys during each dead-time period of the converter.

US Pat. No. 10,243,481

POWER SUPPLIES HAVING FEEDFORWARD CONTROL USING PULSE MODULATION AND DEMODULATION

Astec International Limit...

1. An isolated AC-DC power supply comprising:an input terminal for receiving an AC voltage input;
an output terminal for providing a DC voltage output;
a PFC converter coupled to the input terminal;
a DC-DC converter coupled between the PFC converter and the output terminal;
a controller coupled to the DC-DC converter and configured to control switching operation of the DC-DC converter;
a pulse modulator coupled to an output of the PFC converter to receive a signal representative of voltage ripple at the output of the PFC converter, the pulse modulator configured to modulate a pulse signal based on an amplitude of the voltage ripple; and
a pulse demodulator coupled to the pulse modulator to receive the modulated pulse signal, the pulse demodulator configured to demodulate the modulated pulse signal and provide a demodulated signal to the controller to adjust switching operation of the DC-DC converter.

US Pat. No. 10,236,764

SNUBBER CIRCUITS FOR POWER CONVERTERS

Astec International Limit...

1. A power converter for converting an input power at an input of the converter to an output power at an output of the converter, the power converter comprising:a power conversion circuit including a switching device coupled to a reference potential, and an inductance coupled to the switching device; and
a snubber circuit coupled to the power conversion circuit, the snubber circuit including a snubber switching device, a capacitance coupled to the snubber switching device, and an auxiliary inductance coupled to the inductance of the power conversion circuit and the snubber switching device, the snubber switching device and the capacitance coupled across the switching device of the power conversion circuit, the capacitance adapted to store leakage energy output from the power conversion circuit and discharge at least a portion of the stored leakage energy via the snubber switching device.

US Pat. No. 10,314,164

CIRCUIT BOARD ASSEMBLIES AND METHODS OF ASSEMBLING CIRCUIT BOARDS AND BUS BARS

Astec International Limit...

1. A circuit board assembly comprising:a printed circuit board including a first surface and a second surface opposite the first surface, the printed circuit board defining an opening having at least one side extending from the first surface of the printed circuit board to the second surface of the printed circuit board;
a bus bar including a first surface, a second surface opposite the first surface, and at least one side extending from the first surface of the bus bar to the second surface of the bus bar, the bus bar secured in the opening of the printed circuit board via a press-fit, with a slot defined between the at least one side of the bus bar and the at least one side of the opening defined by the printed circuit board;
an electrical lead positioned in the slot defined between the at least one side of the bus bar and the at least one side of the opening defined by the printed circuit board; and
solder disposed between the electrical lead and the bus bar to electrically couple the electrical lead and the bus bar.

US Pat. No. 10,368,431

COOLING ASSEMBLIES FOR ELECTRONIC DEVICES

Astec International Limit...

1. A cooling assembly for cooling electronic devices, the cooling assembly comprising:a circuit board having a first surface and a second surface opposite the first surface;
a first set of electronic devices, a second set of electronic devices, and a third set of electronic devices, each set including at least two electronic devices electrically coupled in parallel and disposed on the first surface of the circuit board, at least one of the electronic devices of the third set and at least one of the electronic devices of the second set positioned between the at least two electronic devices of the first set; and
a heat sink disposed on the second surface of the circuit board, the heat sink including a first heat sink portion in thermal contact with the first set of electronic devices, a second heat sink portion in thermal contact with the second set of electronic devices, and a third heat sink portion in thermal contact with the third set of electronic devices, the first, second and third heat sink portions positioned in an interleaved arrangement to overlap one another while remaining electrically isolated from one another.

US Pat. No. 10,320,279

POWER SUPPLIES AND METHODS FOR REDUCING COMMON MODE NOISE

Astec International Limit...

1. A switched-mode power supply comprising:an input for receiving an input voltage from a voltage source;
an output for providing an output voltage to a load;
a transformer having a primary winding, a secondary winding, and a conductive shield disposed between the primary winding and the secondary winding; and
a neutralization signal generator circuit coupled to the conductive shield and adapted to apply a neutralization signal to the conductive shield, the conductive shield adapted to conduct the received neutralization signal to reduce a common mode noise between the primary winding and the secondary winding of the transformer, wherein the neutralization signal has an adjustable amplitude and/or phase, and the neutralization signal generator circuit is configured to automatically adjust the neutralization signal in response to measured common mode noise between the primary winding and the secondary winding of the transformer by adjusting at least one of a potentiometer, an adjustable gain amplifier and a second transformer.

US Pat. No. 10,340,787

POWER FACTOR CORRECTION STAGE CONTROL DURING START-UP FOR EFFICIENT USE OF A NEGATIVE TEMPERATURE COEFFICIENT THERMISTOR

Astec International Limit...

1. A power factor correction (PFC) stage of a power supply unit, the PFC stage comprising:a PFC circuit including a rectifier circuit for connection to an input power source, a PFC controller circuit connected to the rectifier circuit and including a PFC switch, a current sensor connected to the PFC switch of the PFC controller circuit, at least one high frequency bypass capacitor connected between the PFC controller circuit and the rectifier circuit, and at least one bulk storage capacitor connected between the PFC controller circuit and an output of the PFC stage; and
a negative temperature coefficient (NTC) thermistor connected in series with the PFC switch of the PFC controller circuit and the current sensor to limit an in-rush current in the PFC circuit, and
wherein, during a start-up of the power supply unit, the PFC controller circuit is configured to turn-on the PFC switch continuously to allow a current through the NTC thermistor to increase and a resistance of the NTC thermistor to decrease, and turn-off the PFC switch after the current through the NTC thermistor is sensed as being equal to or greater than a preset value based on the resistance of the NTC thermistor.

US Pat. No. 10,340,685

INPUT REDUNDANT CIRCUIT

Astec International Limit...

1. An input redundant circuit, comprising:a core power supply including a boosting circuit;
a first input port for receiving a first input voltage;
a second input port for receiving a second input voltage;
a relay unit connected to the first input port and the second input port to selectively connect and disconnect the first input voltage and the second input voltage to the core power supply, the core power supply configured to inhibit an input current to the boosting circuit and switch the relay after inhibiting the input current to the boosting circuit; and
a surge current limiting circuit coupled to the core power supply and configured to limit a surge current generated when the relay unit is switched between the first input voltage and the second input voltage.

US Pat. No. 10,374,519

LLC RESONANT CONVERTER AND METHOD FOR SUPPRESSING RIPPLES IN OUTPUT VOLTAGE THEREOF

Astec International Limit...

1. An LLC resonant converter, comprising:a half-bridge or full-bridge chopper having a driving circuit;
an inductance-capacitance series resonant network coupled to the chopper;
an isolation transformer coupled to the resonant network;
a rectification and filtering circuit coupled to the isolation transformer;
a linear proportional feedforward controller comprising at least one of a low-pass filter and a band-pass filter coupled to generate a feedforward signal based on an input voltage; and
a controlled oscillator coupled to receive the feedforward signal from the feedforward controller and to control an operating frequency of the chopper via the driving circuit based on the feedforward signal.