US Pat. No. 9,730,283

DRIVERS AND DRIVING METHODS FOR A LED STRING, CAPABLE OF PROVIDING LED SHORT PROTECTION OR AVOIDING LED FLICKERING

LEADTREND TECHNOLOGY CORP...

1. A driver for driving a LED string consisting of LEDs, the driver comprising:
a current switch connected in series with the LED string between a power line and a ground line; and
a switched mode power supply, for powering the power line to regulate a signal representing a current passing through the
LED string, wherein the switched mode power supply comprises an enable node and a clamping circuit;

wherein an enable signal at the enable node is capable of switching the current switch; and
when a predetermined event occurs the clamping circuit clamps the enable signal to have a predetermined logic value, the current
switch thereby being kept either open or short.

US Pat. No. 9,059,638

CONTROL METHODS AND APPARATUSES FOR SWITCHING MODE POWER SUPPLIES

LEADTREND TECHNOLOGY CORP...

18. A controller for driving a power switch, comprising:
a driver comprising:
a high-side driver for turning ON the power switch by providing to a control node of the power switch a driving current to
raise a voltage at the control node; and

a low-side driver for turning OFF the power switch by providing to the control node another driving current to lower the voltage;
a control logic for controlling the driver; and
a condition decider coupled to the control logic, for terminating a dead time according to a conduction current passing through
the power switch;

wherein during the dead time, both the high-side and low-side drivers are disabled, not driving the control node of the power
switch.

US Pat. No. 9,337,739

POWER CONTROLLER WITH OVER POWER PROTECTION

LEADTREND TECHNOLOGY CORP...

1. A power controller with over power protection, capable of providing a pulse-width-modulation signal to control a power
switch, the power controller comprising:
a pulse width modulator for generating the pulse-width-modulation signal;
a first oscillator, coupled to the pulse width modulator, for determining a cycle time of the pulse-width-modulation signal;
a second oscillator, independent from the first oscillator, for determining a maximum over power duration when the cycle time
is determined by the first oscillator; and

an over power detector for detecting an occurrence of an over power event;
wherein when the over power event lasts for the maximum over power duration, the pulse-width-modulation signal switches OFF
the power switch constantly;

wherein the first oscillator is controlled by a compensation voltage in association with an output power of a power supply;
wherein when the compensation voltage is about a preset over-power voltage, the first oscillator provides a first constant
frequency;

when the compensation voltage exceeds the preset over-power voltage, the first oscillator provides a second constant frequency
higher than the first constant frequency; and

the occurrence of the over power event is determined by comparing the preset over-power voltage and the compensation voltage.

US Pat. No. 9,077,250

CONSTANT CURRENT CONTROL UNITS AND CONTROL METHODS THEREOF FOR PRIMARY SIDE CONTROL

LEADTREND TECHNOLOGY CORP...

1. A constant current control unit, for a switched mode power supply with primary side control, wherein the switched mode
power supply has a power switch and an inductive device, the constant current control unit comprising:
a voltage-waveform detector, comprising a comparator with two inputs receiving a feedback voltage signal and a delayed signal
respectively to determine a discharge time of the inductive device when the power switch is OFF by comparing the feedback
voltage signal with the delayed signal, wherein the feedback voltage signal is provided from a reflective voltage of the inductive
device and the delayed signal is generated by delaying the feedback voltage signal; and

a constant current controller for generating an integral result according to the discharge time and a current-sense signal,
wherein the current-sense signal is provided based on a current flowing through the inductive device;

wherein the integral result is used for controlling the power switch to stabilize a maximum average output current of the
switched mode power supply; and

wherein the voltage-waveform detector comprises a low-pass filter, for low passing the feedback voltage signal to generate
the delayed signal, and the low-pass filter is connected between the two inputs.

US Pat. No. 9,301,364

DRIVERS AND DRIVING METHODS FOR A LED STRING, CAPABLE OF PROVIDING LED SHORT PROTECTION OR AVOIDING LED FLICKERING

LEADTREND TECHNOLOGY CORP...

1. A driver for driving a LED string consisting of LEDs, the driver comprising:
a current switch connected in series with the LED string between a power line and a ground line; and
a switched mode power supply, for powering the power line to regulate a signal representing a current passing through the
LED string, wherein the switched mode power supply comprises an enable node and a clamping circuit;

wherein an enable signal at the enable node is capable of switching the current switch; and
when a predetermined event occurs the clamping circuit clamps the enable signal to have a predetermined logic value, the current
switch thereby being kept either open or short;

wherein the predetermined event is the signal exceeding a predetermined value, and when the predetermined event occurs the
clamping circuit clamps the enable signal to be deasserted and to make the current switch open, thereby providing LED short
protection.

US Pat. No. 9,215,773

CONTROL METHODS AND BACKLIGHT CONTROLLERS FOR LIGHT DIMMING

LEADTREND TECHNOLOGY CORP...

1. A control method for light dimming, comprising:
providing a dimming condition signal, wherein a first logic value of the dimming condition signal represents a light emitting
device is expected to be emitting light, and a second logic value of the dimming condition signal represents the light emitting
device is expected not to be emitting light, wherein the duration when the dimming condition signal is at the first logic
value is a dimming-ON time;

providing, in the dimming-ON time, a close loop to make a power converter convert electric energy to the light emitting device
such that the light emitting device is capable of emitting light, wherein a power-ON time is the duration when the power converter
converts electric energy to the light emitting device; and

continuing, when the dimming condition signal is switched to be at the second logic value and the dimming-ON time is less
than a minimum power-ON time, the power converter converting the electric energy to the light emitting device so as to keep
the power-ON time not less than the minimum power-ON time.

US Pat. No. 9,800,135

RIPPLE SUPPRESSOR

LEADTREND TECHNOLOGY CORP...

14. A ripple suppressor, comprising:
a voltage-controlled current source with a control node, a first channel node and a second channel node, wherein a control
voltage at the control node controls a channel current through a path connecting the first and second channel nodes, and the
voltage-controlled current source receives a current-setting signal to generate the control voltage, so as to stabilize the
channel current in response to the current-setting signal;

a stabilizer coupled to the first channel node for generating the current-setting signal, wherein the stabilizer at least
provides low-pass filtering to substantially stabilize the current-setting signal in response to a first channel voltage at
the first channel node; and

an auto-calibration circuit for controlling the stabilizer in response to the control voltage, so as to make the control voltage
in compliance with a first predetermined condition;

wherein the first predetermined condition is that the control voltage is substantially limited under a predetermined top limit,
or that the control voltage has an average substantially equal to a predetermined value.

US Pat. No. 9,621,027

POWER SUPPLIES AND CONTROL METHODS CAPABLE OF IMPROVING POWER FACTOR DURING LIGHT LOAD

LEADTREND TECHNOLOGY CORP...

1. An apparatus capable of improving power factor of a power supply powered by a high power line and a ground power line,
wherein the power supply comprises a power switch, the apparatus comprising:
a line voltage detector, for providing a scaled voltage to represent a line voltage of the high power line; and
an ON time controller, comprising:
a valley voltage detector, for providing, in response to the scaled voltage, a valley representative representing a valley
voltage of the line voltage;

wherein the ON time controller controls an ON time of the power switch in response to the valley representative; and
wherein when the valley voltage increases the valley representative makes the ON time increase.

US Pat. No. 9,673,720

SYNCHRONOUS RECTIFICATION CONTROLLER AND RELATIVE DEAD-TIME CONTROL METHOD

LEADTREND TECHNOLOGY CORP...

1. A synchronous rectification control method, suitable for a switching mode power supply with a synchronous rectifier, comprising:
providing a synchronous rectification controller with a first pin;
sampling a pin voltage at the first pin to generate a sampled voltage;
after the sampling, providing a detection current flowing out of the synchronous rectification controller from the first pin;
generating digital dead-time control signals in response to a difference between the pin voltage and the sampled voltage;
controlling the synchronous rectifier based upon the digital dead-time control signals to determine a dead time of the synchronous
rectifier;

comparing the sampled voltage with the pin voltage to generate an analog gap signal;
converting the analog gap signal into digital signals; and
latching the digital signals to provide the digital dead-time control signals.

US Pat. No. 9,608,531

TIMING CONTROL METHOD AND APPARATUS FOR SYNCHRONOUS RECTIFIER USING ESTIMATED DURATION SIGNAL

LEADTREND TECHNOLOGY CORP...

1. A timing control method, suitable for a switching mode power supply with a synchronous rectifier, comprising:
generating a present duration signal at a first capacitor, wherein the present duration signal corresponds to a discharge
time when the synchronous rectifier is operated in a first condition;

providing an estimated duration signal at a second capacitor;
controlling the synchronous rectifier based on the estimated duration signal;
during a period of time when the synchronous rectifier is operated in a second condition different from the first condition,
updating the estimated duration signal by charge sharing between the first and second capacitors;

providing a current source to generate a charge current charging the first capacitor;
connecting a resistor between the current source and the first capacitor; and
comparing a voltage at a joint node between the resistor and the current source with the estimated duration signal to control
the synchronous rectifier.

US Pat. No. 9,974,124

LED CONTROLLERS FOR DIMMING AT LEAST ONE LED STRING

LEADTREND TECHNOLOGY CORP...

1. A control circuit capable of controlling the light dimming of a light emitting device, the control circuit comprising:a current driver, in response to a dimming signal, for selectively causing a driving current flowing through the light emitting device, wherein the dimming signal is capable of defining a dimming ON period and a dimming OFF period;
a pulse-width modulator for generating a PWM signal to control a power switch, in order to build up a driving voltage at a power node of the light emitting device, wherein the PWM signal is generated in response to a compensation signal;
a feedback circuit, based upon a feedback voltage from the light emitting device, for driving a compensation capacitor to generate the compensation signal; and
a decoupling circuit, for defining a decoupling period at the start of the dimming ON period and causing the feedback circuit to not drive the compensation capacitor during the decoupling period;
wherein the feedback circuit comprises a transconductor whose output is in high impedance during the decoupling period and the dimming OFF period.

US Pat. No. 9,723,664

CONTROL METHODS AND POWER CONVERTERS SUITABLE FOR TRIAC DIMMING

LEADTREND TECHNOLOGY CORP...

1. A power converter suitable for converting an input power source into an output power source, the power converter comprising:
a power controller powered by an operation power source with an operation voltage, comprising:
a high-voltage pin coupled to the input power source;
a high-voltage device capable of draining a conduction current from the input power source via the high-voltage pin;
a high-voltage startup control circuit, for detecting the operation voltage;
a cutoff-time detection circuit for detecting an input voltage of the input power source to provide a detected voltage; and
a demultiplexer coupled to the high-voltage device, the high-voltage startup control circuit and the cutoff-time detection
circuit, for forwarding the conduction current to the operation power source during a startup procedure and to a ground line
when the detected voltage is below a setting voltage;

wherein the conduction current charges the operation power source during the startup procedure; and
the conduction current goes through the high-voltage device and does not charge the operation power source when the detected
voltage is below the setting voltage.

US Pat. No. 9,774,267

POWER SUPPLIES AND CONTROL METHODS SUITABLE FOR SEQUENTIALLY TRANSMITTING COMMAND BITS FROM SECONDARY SIDE TO PRIMARY SIDE

LEADTREND TECHNOLOGY CORP...

1. A control circuit suitable for a power supply with a primary side and a secondary side galvanically isolated from each
other, wherein the power supply comprises a transformer with a primary winding and a secondary winding magnetically coupled
to each other, the primary winding and the secondary winding are located in the primary side and the secondary side respectively,
and the transformer is configured to transfer electric energy from the primary side to the secondary side and to build an
output power source in the secondary side, the control circuit comprising:
a primary-side controller in the primary side, configured to control a current through the primary winding; and
a secondary-side controller in the secondary side, powered by the output power source, configured to provide a command code
with several command bits sequentially transmitted to the primary-side controller so as to set an operation mode that the
primary-side controller operates in;

wherein the primary-side controller determines a voltage rating of the output power source based upon the command code with
the command bits.

US Pat. No. 9,825,534

DUMMY LOAD CONTROLLERS AND CONTROL METHODS FOR POWER SUPPLIES CAPABLE OF QUICKLY LOWERING OUTPUT VOLTAGE AT OUTPUT NODE

LEADTREND TECHNOLOGY CORP...

11. A dummy-load control unit, suitable for a power supply with a primary winding and a secondary winding isolated from each
other, wherein the secondary winding is configured to de-energize and to build an output voltage at an output node for powering
a load, the dummy-load control unit comprising:
a detection node coupled to the secondary winding;
a first comparator with a first input coupled to the detection node, a second input coupled to a reference voltage and an
output providing a comparison result;

a debounce circuit coupled to the first comparator for turning on a timeout signal when the comparison result has stayed in
a first predetermined value for a predetermined reference time;

a second comparator for comparing the output voltage with a predetermined voltage; and
a logic coupled to the debounce circuit and the second comparator;
wherein when the output voltage exceeds the predetermined voltage and the timeout signal is turned on, the logic provides
a discharge path for discharging the output node to lower the output voltage.

US Pat. No. 9,408,276

SHORT CIRCUIT DETECTION CIRCUIT AND CONTROL METHOD THEREOF

Leadtrend Technology Corp...

1. A short circuit detection circuit for detecting short circuit of a series of light-emitting diodes, the short circuit detection
circuit comprising:
a constant current source for providing setting current;
a rectifier coupled between a feedback terminal and the constant current source, wherein the feedback terminal is coupled
to a terminal of the series of light-emitting diodes for making the setting current sink the feedback terminal when a feedback
voltage of the feedback terminal exceeds a short circuit reference voltage; and

a detector for detecting the feedback voltage of the feedback terminal, and triggering short-circuit protection to make the
series of light-emitting diodes be turned off when the feedback voltage is higher than a predetermined value.

US Pat. No. 10,193,456

PULSE WIDTH MODULATION CONTROLLER AND RELEVANT CONTROL METHOD HAVING MINIMUM ON TIME IN RESPONSE TO VOLTAGE PEAK OF LINE VOLTAGE

LEADTREND TECHNOLOGY CORP...

1. A PWM controller for providing to a power switch a PWM signal determining an ON time and an OFF time of the power switch, the PWM controller comprising:a peak detector for detecting a voltage peak of a line voltage generated by rectifying an alternating-current input voltage;
an OFF-time control unit for controlling the PWM signal and determining the OFF time in response to a compensation voltage, wherein the compensation voltage is in response to an output voltage of a power supply comprising the power switch and the PWM controller; and
an ON-time control unit for controlling the PWM signal and determining the ON time in response to the compensation voltage and the voltage peak, wherein the ON-time control unit is configured to make the ON time not less than a minimum ON time, and the minimum ON time is determined in response to the voltage peak;
wherein the ON-time control unit comprises a ramp signal generator for providing a ramp signal compared with the compensation voltage to determine the ON time; and
the ramp signal generator provides a charging current in response to the voltage peak to charge a capacitor and generate the ramp signal.

US Pat. No. 10,075,082

SWITCHING MODE POWER SUPPLIES WITH FAST LOAD-TRANSIENT RESPONSE

LEADTREND TECHNOLOGY CORP...

1. A power supply with a primary side and a secondary side isolated from each other, the power supply comprising:a primary-side control circuit on the primary side, for controlling a power switch to convert an input power source on the primary side into an output power source on the secondary side, wherein the output power source has an output voltage; and
a secondary-side control circuit on the secondary side, for detecting a falling rate of the output voltage and sending information to the primary-side control circuit when the falling rate exceeds a predetermined rate;
wherein, in response to the information, the primary-side control circuit starts a new switching cycle of the power switch; and
wherein the secondary-side control circuit comprises:
a voltage-to-current converter for converting the output voltage into a corresponding current;
a track-and-hold circuit for holding a sample current during a hold time, where the sample current equals to the corresponding current at the beginning of the hold time; and
a decider for determining whether the sample current exceeds a summation of the corresponding current and a reference current during the hold time, so as to determine whether the falling rate exceeds the predetermined rate.

US Pat. No. 9,882,494

SWITCHING-MODE POWER SUPPLIES CAPABLE OF OPERATING AT VALLEY SWITCHING, AND RELEVANT CONTROL METHODS

LEADTREND TECHNOLOGY CORP...

9. A power controller suitable for use in a power supply with an inductive device and a power switch, wherein when the power
switch is OFF the inductive device is capable of providing an oscillation signal with at least one signal valley, the power
controller comprising:
a valley detector coupled to the inductive device, for detecting the signal valley to provide a valley signal; and
a valley selector receiving the valley signal, for counting an occurrence number of the signal valley, comparing the occurrence
number with a lock number, and when the occurrence number and the lock number fit a predetermined condition, providing a pass
signal that allows the valley signal to make the power switch turned ON so a cycle time starts at a start moment;

wherein the valley selector checks if the start moment falls within an expectation window, and changes the lock number if
the start moment falls outside of the expectation window.

US Pat. No. 9,917,523

CONTROL METHODS AND SWITCHING MODE POWER SUPPLIES WITH IMPROVED DYNAMIC RESPONSE AND REDUCED SWITCHING LOSS

LEADTREND TECHNOLOGY CORP...

1. A control method for a switching mode power supply with a transformer and a power switch, comprising:
providing a PWM signal to control the power switch, wherein the PWM signal has a switching frequency;
detecting a cross voltage of the transformer to provide a de-magnetization time;
controlling the switching frequency in response to a compensation voltage and a sleep signal, wherein the compensation voltage
is generated based on an output voltage of the switching mode power supply;

providing the sleep signal in response to the de-magnetization time and a current sense signal, wherein the current sense
signal is a representative of a winding current of the transformer;

making the switching frequency not less than a first minimum value if the sleep signal is deasserted; and
making the switching frequency not less than a second minimum value if the sleep signal is asserted,
wherein the second minimum value is less than the first minimum value.

US Pat. No. 9,985,529

POWER CONTROL METHOD AND RELATED APPARATUS CAPABLE OF PROVIDING COMPENSATION TO INDUCTANCE VARIATION

LEADTREND TECHNOLOGY CORP...

9. A control circuit suitable for use in a power supply converting an input voltage into an output voltage, wherein the power supply includes a power controller controlling a power switch connected to an inductive device, and the control circuit is in the power controller and for compensating inductance variation of the inductive device, the control circuit comprising:a comparator with first and second inputs;
a first capacitor connected to the first input, wherein the comparator is configured to provide a sampling time having a length substantially independent from an ON time of the power switch, the input voltage and an inductance of the inductive device;
a sample-and-hold circuit for holding a sample voltage after the sampling time by sampling during the ON time a current-sense signal, a representative of a winding current through the inductive device; and
an output rating control unit for controlling the power switch in response to the sample voltage, so as to make the output voltage comply with an output rating.

US Pat. No. 10,230,297

HIGH-VOLTAGE STARTUP CIRCUITS AND CONTROL METHODS THEREOF

LEADTREND TECHNOLOGY CORP...

11. A control method for high-voltage charging, in use of a high-voltage startup circuit comprising a ultra-high voltage transistor and a main NMOS transistor, wherein the main NMOS transistor has a first gate, the ultra-high voltage transistor is capable of sustaining an input voltage higher than 400V, and the ultra-high voltage transistor is connected in series with the main NMOS transistor via a joint node between a high-voltage pin and an operating voltage pin, the control method comprising:coupling the joint node to the first gate to turn ON the main NMOS transistor, so as to make a charging current flow through the high-voltage pin, the ultra-high voltage transistor, the main NMOS transistor and the operating voltage pin to increase an operating voltage at the operating voltage pin; and
decoupling the joint node from the first gate and pulling down a first gate voltage of the first gate, so as to turn OFF the main NMOS transistor and stop the charging current.

US Pat. No. 10,397,997

DIMMING CONTROLLERS AND DIMMING METHODS CAPABLE OF RECEIVING PWM DIMMING SIGNAL AND DC DIMMING SIGNAL

LEADTREND TECHNOLOGY CORP...

1. A dimming controller for dimming a light-emitting device, comprising:an input node for receiving a dimming signal;
a type identifier connected to the input node, for identifying whether the dimming signal is of a first type or a second type;
a signal converter connected to the input node, for generating a first signal in response to the dimming signal, wherein the first signal is of the first type; and
a multiplexer controlled by the type identifier, having two inputs receiving the first signal and the dimming signal respectively, wherein the type identifier makes the multiplexer forward the first signal to a driver driving the light-emitting device if the dimming signal is identified as the second type, and the dimming signal to the drive if the dimming signal is identified as the first type.

US Pat. No. 10,319,713

SEMICONDUCTOR DEVICES WITH ELECTROSTATIC DISCHARGE ROBUSTNESS

LEADTREND TECHNOLOGY CORP...

1. A semiconductor device with electrostatic discharge robustness, comprising:a semiconductor substrate of a first type;
a switch device, comprising:
a drain region formed on the semiconductor substrate, wherein the drain region is of a second type opposite to the first type;
a source region of the second type, formed on the semiconductor substrate and with a first arch portion facing inwardly toward a first direction, wherein the first arch portion at least partially surrounds the drain region; and
a control gate, structured to control electric connection between the drain region and the source region; and
an ESD protection device, comprising:
a first region of the first type formed on the semiconductor substrate; and
a second region of the first type formed on the semiconductor substrate and with a second arch portion facing inwardly toward a second direction, wherein the second arch portion at least partially surrounds the first region;
wherein the first direction is opposite to the second direction, and the switch device is a depletion-mode junction effect transistor.

US Pat. No. 10,348,208

POWER CONTROLLERS AND CONTROL METHODS THEREOF FOR SWITCHING MODE POWER SUPPLIES

LEADTREND TECHNOLOGY CORP...

1. A control method suitable for a switching mode power supply, the control method comprising:controlling a power switch according to a clock signal, to transfer electrical energy from an input power source to an output power source;
providing a feedback signal in response to an output voltage of the output power source; and
generating the clock signal in response to the feedback signal and an input voltage of the input power source, wherein the clock signal has a clock frequency determining a switching frequency of the power switch;
wherein when the feedback signal exceeds a first predetermined level, the clock frequency increases in response to decrease to the input voltage; and
when the feedback signal is under a second predetermined level lower than the first predetermined level, the clock frequency is independent from the input voltage.

US Pat. No. 9,190,912

POWER CONTROL CIRCUIT DETECTING A PHASE OF A BURST INITIALIZING SIGNAL AND POWER CONTROLLING METHOD DETECTING A PHASE OF A BURST INITIALIZING SIGNAL

Leadtrend Technology Corp...

1. A power control circuit for a power supply, comprising:
a clock generator for providing a clock signal;
a phase controller for detecting a phase of a group reference signal and a phase of a burst initialization signal to generate
a burst signal, so as to cause a phase of the burst signal to occur no earlier than the phase of the group reference signal,
wherein the burst signal is capable of switching the power supply between a switching state and a non-switching state; and

a power stabilizer for substantially keeping an outputted power of the power supply constant after the power supply is switched
from the non-switching state to the switching state;

wherein the group reference signal is generated according to the clock signal and has a frequency lower than a frequency of
the clock signal; and

wherein the burst initialization signal is controlled by an output voltage of the power supply.

US Pat. No. 9,160,233

CONTROLLER FOR CONTROLLING A POWER CONVERTER TO OUTPUT CONSTANT POWER AND RELATED METHOD THEREOF

Leadtrend Technology Corp...

1. A controller for controlling a power converter to output constant power, the controller comprising:
a current sensing module coupled to a secondary side of the power converter for generating a sensing current according to
an output current flowing through the secondary side of the power converter;

a voltage generation module coupled to the current sensing module for generating a set voltage corresponding to a reciprocal
of the sensing current according to the sensing current; and

a voltage regulation module coupled to the voltage generation module and the secondary side of the power converter for generating
a regulation voltage to a feedback circuit of the secondary side of the power converter according to the set voltage and a
sensing voltage corresponding to an output voltage of the secondary side of the power converter, wherein the feedback circuit
and a primary side of the power converter regulate the output voltage according to the regulation voltage;

wherein a product of the output voltage and the output current is a constant value.

US Pat. No. 10,347,756

HIGH-VOLTAGE METAL-OXIDE-SEMICONDUCTOR TRANSISTOR CAPABLE OF PREVENTING OCCURRENCE OF EXCEEDINGLY-LARGE REVERSE CURRENT

LEADTREND TECHNOLOGY CORP...

1. A high-voltage semiconductor device with a Schottky diode, comprising:a semiconductor substrate having an upper surface;
a body region of a first type, formed directly on the upper surface of the semiconductor substrate;
a drift region of a second type, formed directly on the upper surface of the semiconductor substrate, wherein the second type is opposite to the first type, and the drift region adjoins the body region to form a first junction therebetween;
a first metal electrode, positioned on the drift region to form a Schottky contact as the Schottky diode;
a first heavily-doped region of the second type, formed in the body region;
a second metal electrode, positioned on the first heavily-doped region to form an ohmic contact; and
a control gate structure comprising a gate electrode capable of controlling electric connection between the drift region and the first heavily-doped region;
wherein the semiconductor substrate contacts and shorts substantially to the body region; and
in view of second-type impurity dosage concentration, the first heavily-doped region is heavier than the drift region.

US Pat. No. 9,343,983

CONTROLLER FOR GENERATING JITTERS IN A CONSTANT CURRENT MODE OF A POWER CONVERTER AND METHOD THEREOF

Leadtrend Technology Corp...

1. A controller for generating jitters in a constant current mode of a power converter, the controller comprising:
a current pin for receiving a primary side voltage determined according to a resistor and a primary side current flowing through
the power converter;

an auxiliary pin for receiving a voltage corresponding to an auxiliary winding of the power converter;
a constant current control unit coupled to the current pin and the auxiliary pin for generating an adjustment signal according
to the primary side voltage, a discharge time corresponding to the voltage, and a reference voltage, wherein the reference
voltage has a predetermined range jitter voltage; and

a control signal generation unit coupled to the constant current control unit for adjusting a period of a gate control signal
according to the adjustment signal, wherein the control signal generation unit comprises:

an oscillator for determining an oscillation frequency according to the adjustment signal, wherein the oscillation frequency
is used for adjusting the period of the gate control signal.

US Pat. No. 10,476,388

SIMO BASED DC-DC CONVERTERS FOR THERMOELECTRIC ENERGY HARVESTING

LEADTREND TECHNOLOGY CORP...

1. A single-inductor multiple-output (SIMO) power converter for converting an input voltage to generate an output voltage and a biasing voltage, the SIMO power converter comprising:an inductor configured to store energy from the input voltage;
a primary power switch with a control node, connected between the inductor and the output voltage, wherein the primary power switch is configured to deliver a first part of the energy to the output voltage; and
a control circuit configured to control the primary power switch, the control circuit comprising:
an auxiliary power switch, connected between the inductor and the biasing voltage, wherein the auxiliary power switch is configured to deliver a second part of the energy to the biasing voltage; and
a driver configured to drive the control node and to determine a signal level at the control node according to the biasing voltage, the biasing voltage performing as a power source for the driver;
wherein the auxiliary power switch delivers the second part of the energy to the biasing voltage in response to a turn-on voltage of the primary power switch, the turn-on voltage being a voltage drop across a conduction channel of the primary power switch when the primary power switch is turned on.

US Pat. No. 9,350,237

CONTROL CIRCUIT APPLICABLE TO POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A control circuit applicable to a power converter, comprising:
an auxiliary pin for receiving an auxiliary voltage of an auxiliary winding of the power converter;
a first detection unit for detecting a first time point when the auxiliary voltage begins resonance, and outputting a first
detection signal according to the first time point;

a second detection unit for detecting a second time point when the auxiliary voltage reaches a predetermined voltage, and
outputting a second detection signal according to the second time point;

a delay time controller for obtaining a delay time according to an output time difference between the first detection signal
and the second detection signal, and outputting a driving signal with delay of the delay time when receiving the second detection
signal; and

a gate control signal generator for generating a gate control signal to a power switch of the power converter according to
the driving signal outputted by the delay time controller.

US Pat. No. 9,101,033

SHORT PROTECTION CONTROL CIRCUITS AND RELATED CONTROL METHODS

Leadtrend Technology Corp...

1. A control method for use in controlling a short protection mechanism providing short protection to a plurality of light-emitting
diode (LED) chains, wherein a plurality of driving currents flow through the LED chains, the control method comprising:
detecting whether at least one of the driving currents encounters an under-current event;
blocking a short protection mechanism and resetting a timer when the under-current event is encountered, wherein the short
protection mechanism provides short protection to the LED chains; and

resuming the short protection mechanism after the short protection mechanism is blocked for at least a predetermined time
period.

US Pat. No. 9,800,163

METHOD FOR CONTROLLING A DEAD TIME OF A SECONDARY SIDE OF A POWER CONVERTER

Leadtrend Technology Corp...

1. A method for controlling a dead time of a secondary side of a power converter, the method comprising:
giving a previous first turning-on time and a current first turning-on time corresponding to a primary side of the power converter;
generating a first voltage and a second voltage according to the previous first turning-on time and the current first turning-on
time, respectively;

generating a current first target voltage according to the first voltage, the second voltage, and an ideal voltage corresponding
to a previous ideal second turning-on time of the secondary side; and

determining a current second turning-on time of the secondary side according to a first ramp voltage corresponding to a current
ideal second turning-on time of the secondary side and the current first target voltage, wherein a difference between the
current second turning-on time and the current ideal second turning-on time is a current dead time of the secondary side;

wherein when the first voltage is not equal to the second voltage, the current dead time is not equal to a previous dead time
of the secondary side.

US Pat. No. 9,197,054

CIRCUIT FOR CONTROLLING A LATCH MODE OF A PULSE WIDTH MODULATION CIRCUIT AND METHOD THEREOF

Leadtrend Technology Corp...

1. A circuit for controlling a latch mode of a pulse width modulation circuit, the circuit comprising:
a D flip-flop for generating a switch control signal according to a latch enable signal;
a voltage generation unit comprising a voltage divider resistor group, wherein the voltage generation unit generates a discharge
current, and the voltage divider resistor group generates a first voltage according to the discharge current and a charge
current generated by a primary side of an alternating current/direct current converter which the pulse width modulation circuit
is applied to when the voltage generation unit is turned on according to the switch control signal, wherein a voltage of a
predetermined pin of the pulse width modulation circuit is equal to a predetermined voltage when the discharge current is
equal to the charge current;

a comparator for comparing a reference voltage with the first voltage to generate a comparison signal; and
a logic unit for generating a clear signal according to the comparison signal;
wherein the D flip-flop clears the switch control signal according to the clear signal.

US Pat. No. 9,113,506

CIRCUIT WITH ADJUSTABLE PHASE DELAY AND A FEEDBACK VOLTAGE AND METHOD FOR ADJUSTING PHASE DELAY AND A FEEDBACK VOLTAGE

Leadtrend Technology Corp...

1. A circuit with adjustable phase delay and a feedback voltage, comprising:
a delay setting unit for coupling to an external resistor, wherein the delay setting unit generates a delay time according
to the external resistor; and

a phase delay signal generator coupled to the delay setting unit and comprising a plurality of phase delay units, wherein
each phase delay unit corresponds to a lighting module, the phase delay unit comprising:

an edge trigger subunit for receiving an input signal, and generating a positive edge trigger signal and a negative edge trigger
signal according to a positive edge and a negative edge of the input signal, respectively; and

a signal generation subunit coupled to the edge trigger subunit for generating and outputting a phase delay signal according
to the positive edge trigger signal, the negative edge trigger signal, and the delay time, wherein the phase delay signal
lags the input signal for the delay time.

US Pat. No. 9,331,590

DEVICE AND METHOD FOR DETECTING AN AVERAGE OUTPUT CURRENT OF A POWER CONVERTER

Leadtrend Technology Corp...

1. A controller for detecting an output current of a power converter, the controller comprising:
a comparison unit for generating a first variable turning-on time according to a detection voltage, an intermediate voltage,
and a turning-on time of a power switch of a primary side of the power converter, wherein a second variable turning-on time
is equal to the turning-on time minus the first variable turning-on time; and

an intermediate voltage generation unit coupled to the comparison unit, a charge current, and a discharge current for adjusting
the intermediate voltage according to the first variable turning-on time, the second variable turning-on time, the turning-on
time, the charge current, and the discharge current, wherein the output current corresponds to the intermediate voltage.

US Pat. No. 9,282,608

DIMMING DRIVING SYSTEM AND DIMMING CONTROLLER

Leadtrend Technology Corp...

1. A dimming driving system, comprising:
a transformer having a primary winding and a secondary winding inductively coupled to each other, wherein the secondary winding
is coupled between an output power line and secondary ground;

a lighting device being powered by the output power line and the secondary ground; and
a dimming controller coupled to the secondary winding for controlling current flowing through the lighting device according
to a voltage drop of the secondary winding, the dimming controller comprising:

a dimming phase detection circuit coupled to the secondary winding through a resistor for generating a digital signal according
to the voltage drop of the secondary winding; and

a reference signal providing circuit for providing a current setting signal according to the digital signal;
wherein the current setting signal sets the current flowing through the lighting device.

US Pat. No. 9,343,984

CONTROLLER OF A POWER CONVERTER WITH ADJUSTABLE JITTER AMPLITUDE AND METHOD OF GENERATING ADJUSTABLE JITTER AMPLITUDE THEREOF

Leadtrend Technology Corp...

13. A method of a controller of a power converter generating adjustable jitter amplitude, the controller comprising a feedback
pin, a logic circuit, a current sensing pin, and an auxiliary pin, wherein the logic circuit comprises a first logic unit
and a second logic unit, the method comprising:
the feedback pin receiving a feedback voltage from a secondary side of the power converter, wherein the feedback voltage corresponds
to an output voltage of the secondary side of the power converter;

the logic circuit generating a predetermined-bit digital signal according to a clock, wherein the predetermined-bit digital
signal is first gradually increased and then gradually decreased or first gradually decreased and then gradually increased
during a period of the clock;

the auxiliary pin receiving a voltage corresponding to an auxiliary winding of the power converter;
the current sensing pin generating a detection voltage according to a current flowing through a primary side of the power
converter;

the first logic unit generating the predetermined-bit digital signal according to the clock;
the second logic unit adjusting a resistance of a variable resistor according to the predetermined-bit digital signal;
the second logic unit generating a jitter signal according to the feedback voltage, the resistance of the variable resistor,
and a first resistor; and

determining turning-on time of the primary side of the power converter according to the voltage, the jitter signal, and the
detection voltage.

US Pat. No. 9,236,793

METHODS AND POWER CONTROLLERS FOR PRIMARY SIDE CONTROL

Leadtrend Technology Corp...

7. A power management system comprising:
a transformer having a primary winding, an auxiliary winding, and a secondary winding;
a power switch coupled to the primary winding for controlling an inductance current flowing through the primary winding; and
a power supply controller for controlling the power switch, comprising:
a sampler coupled to a feedback node for sampling the feedback node to generate and output a feedback voltage, wherein the
feedback node is coupled to the auxiliary winding;

a pulse generator for providing a pulse during discharging of the secondary winding for causing the sampler to sample the
feedback node;

a comparator for comparing the feedback voltage and an over-shot reference voltage, wherein the feedback voltage represents
an output voltage of the secondary winding through the feedback node and the auxiliary winding; and

an ON-triggering controller coupled to the comparator, wherein the ON-triggering controller causes the power switch to operate
approximately at a first switching frequency when the feedback voltage is lower than the over-shot reference voltage, and
the ON-triggering controller causes the power switch to operate approximately at a second switching frequency when the feedback
voltage is higher than the over-shot reference voltage;

wherein the second switching frequency is lower than the first switching frequency; the ON-triggering controller is an OFF
time controller coupled to the feedback node; the feedback node is coupled to an auxiliary winding; the OFF time controller
triggers turning on of the power switch when the feedback voltage is lower than the over-shot reference voltage and an auxiliary
winding voltage of the auxiliary winding is approximately in a voltage valley; and when the feedback voltage is larger than
the over-shot reference voltage, the OFF time controller triggers turning on of the power switch after the power switch is
turned off for a maximum OFF time.

US Pat. No. 9,613,572

CONTROLLER AND METHOD FOR DIMMING LIGHT-EMITTING DIODES

Leadtrend Technology Corp...

1. A controller for dimming light-emitting diodes, comprising:
a pulse width modulation pin for receiving a pulse width modulation signal generated by a micro-controller;
a low-pass filter for generating a direct current signal according to the pulse width modulation signal;
a frequency detection unit for generating a logic value according to a threshold and the pulse width modulation signal; and
a control signal generation module coupled to the low-pass filter and the frequency detection unit for generating a switch
control signal to a first switch connected to the light-emitting diodes in series according to the direct current signal,
the logic value, a reference voltage, and the pulse width modulation signal, wherein the first switch is turned on and off
according to the switch control signal, wherein the control signal generation module comprises:

a multiplexer coupled to the low-pass filter and the frequency detection unit for outputting the reference voltage or the
direct current signal according to the logic value, wherein when a frequency of the pulse width modulation signal is lower
than the threshold, the multiplexer outputs the reference voltage, and when the frequency of the pulse width modulation signal
is higher than the threshold, the multiplexer outputs the direct current signal;

a logic unit coupled to the frequency detection unit for receiving the pulse width modulation signal and the logic value,
and outputting an inverse pulse width modulation signal or a first logic value which is inverse to the logic value, wherein
when the frequency of the pulse width modulation signal is lower than the threshold, the logic unit outputs the inverse pulse
width modulation signal, and when the frequency of the pulse width modulation signal is higher than the threshold, the logic
unit outputs the first logic value;

a transmission unit coupled to the multiplexer and the logic unit for outputting one of the reference voltage and the direct
current signal, and outputting one of the inverse pulse width modulation signal and the first logic value;

a second switch coupled to the transmission unit for executing a corresponding operation according to the inverse pulse width
modulation signal or the first logic value, wherein when the second switch is turned on, the first switch is turned off, and
when the second switch is turned off, the first switch is turned on; and

a comparator coupled to the transmission unit for generating the switch control signal to the first switch according to one
of the reference voltage and the direct current signal, and a sensing voltage;

wherein when the comparator generates the switch control signal to the first switch according to the reference voltage and
the sensing voltage, the controller enters the digital dimming mode, and when the comparator generates the switch control
signal to the first switch according to the direct current signal and the sensing voltage, the controller enters the analog
dimming mode;

wherein when a frequency of the pulse width modulation signal is lower than the threshold, the controller enters a digital
dimming mode, and when the frequency of the pulse width modulation signal is higher than the threshold, the controller enters
an analog dimming mode.

US Pat. No. 9,237,614

CAPACITANCE AMPLIFYING CIRCUIT APPLIED TO A CONTROLLER OF A POWER CONVERTOR AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A capacitance amplifying circuit applied to a controller of a power convertor, the capacitance amplifying circuit comprising:
a comparison unit for receiving a feedback voltage corresponding to a load coupled to the power convertor, a dimming signal,
and a reference voltage, and outputting a compensation current according to the feedback voltage and the reference voltage,
wherein when the dimming signal is disabled, the comparison unit is turned off; and

a capacitance amplifying module coupled to the comparison unit for generating an equivalent capacitor, wherein a capacitance
of the equivalent capacitor is K times to a capacitance of a reference capacitor of the capacitance amplifying module, and
K is a real number greater than 1; wherein the compensation current and the equivalent capacitor are used for determining
a compensation voltage, and when the dimming signal is disabled, a closed loop coupled to the comparison unit within the capacitance
amplifying module is changed to an open loop to keep the compensation voltage at a fixed value.

US Pat. No. 9,077,249

POWER CONTROLLER AND POWER MANAGEMENT CONTROL METHOD

Leadtrend Technology Corp...

1. A power controller for controlling a power supply comprising:
a clock generator for providing a clock signal with a clock frequency for periodically switching on and off a power switch;
a low frequency clock generator for providing a low frequency clock signal with a frequency lower than the clock frequency;
and

a protection circuit comprising:
an over power detection circuit for determining if an over power event has occurred according to a feedback signal substantially
controlled by an output voltage of the power supply; and

a logic circuit for keeping the power switch turned off by isolating the power switch from the clock signal when the over
power event lasts longer than an over power tolerance duration, the over power tolerance duration being equal to a first predetermined
number of clock cycles of the low frequency clock signal.

US Pat. No. 9,735,684

CONTROLLERS, POWER SUPPLIES AND CONTROL METHODS

Leadtrend Technology Corp...

1. A control method for a power supply providing an output voltage, the power supply comprising a power switch, an auxiliary
winding, a diode, a first resistor, a sensing resistor, and a second resistor, the control method comprising:
coupling a terminal of a controller to the power switch, wherein the diode and the first resistor are serially coupled between
the auxiliary winding and the terminal;

detecting a sensing voltage of the terminal corresponding to a voltage drop of the sensing resistor when the power switch
is turned on and determining to turn off the power switch according to the sensing voltage of the terminal; and

detecting the sensing voltage of the terminal after the power switch is turned off for a period of delay time, and triggering
an over voltage signal when the sensing voltage of the terminal is over a predetermined value;

wherein the sensing resistor is coupled between the power switch and a grounding line, and the second resistor is coupled
between the sensing resistor and the terminal.

US Pat. No. 9,318,950

CONTROL CIRCUIT FOR REDUCING TOUCH CURRENT OF A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A control circuit for reducing touch current of a power converter, wherein the power converter is a power factor correction
(PFC) power converter, the control circuit comprising:
an auxiliary pin for receiving a voltage generated by an auxiliary winding of the power converter;
a zero-crossing signal generator for generating a zero-crossing signal according to the voltage generated by the auxiliary
winding and a first reference voltage;

a frequency limiting signal generator for generating a frequency limiting signal according to a gate control signal, a burst
mode signal, and the voltage generated by the auxiliary winding, wherein the frequency limiting signal is used for limiting
the gate control signal to a predetermined frequency;

a gate signal generator for generating the gate control signal to a power switch of the power converter according to the frequency
limiting signal and the zero-crossing signal;

a feedback pin for receiving a feedback voltage corresponding to an output voltage of the power converter, wherein the feedback
voltage corresponds to a load coupled to the power converter;

a compensation voltage generation unit for generating a compensation voltage according to the feedback voltage and a second
reference voltage; and

a burst mode signal generation module, comprising:
a first comparator for generating a first comparison result according to the compensation voltage and a burst mode reference
voltage; and

a signal generation unit for generating the burst mode signal to the gate signal generator according to the first comparison
result;

wherein the gate signal generator further generates the gate control signal to the power switch according to the burst mode
signal and the zero-crossing signal.

US Pat. No. 9,048,723

ACTIVE FEEDBACK CONTROL INTEGRATED CIRCUIT APPLIED TO AN ALTERNATING CURRENT/DIRECT CURRENT CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. An active feedback control integrated circuit applied to an alternating current/direct current converter, the active feedback
control integrated circuit comprising:
a feedback pin for receiving a feedback current of an output feedback unit of the alternating current/direct current converter;
an operation unit coupled to the feedback pin for generating an operation signal according to the feedback current;
a control unit coupled to the operation unit for generating a current control signal, wherein the control unit comprises:
a switch having a control terminal coupled to the operation unit for being turned on and turned off according to the operation
signal;

a first current source coupled to a first voltage;
a capacitor coupled between the first current source and ground; and
a second resistor coupled between the switch and the ground;
wherein when the switch is turned off, the current control signal is generated according to the first current source and the
capacitor; and when the switch is turned on, the current control signal is generated according to the first current source,
the capacitor, and the second resistor; and

a controlled-current generation unit coupled to the control unit for generating a controlled current to the feedback pin according
to the current control signal.

US Pat. No. 9,520,791

POWER CONTROLLER WITH MULTI-FUNCTION PIN AND POWER SUPPLY USING THE SAME

Leadtrend Technology Corp...

1. A power supply, comprising:
a power controller having a multi-function pin, an FB pin, a CS pin, and a gate pin, wherein the power controller is a monolithic
integrated circuit;

a power switch having a control terminal coupled to the gate pin, wherein the FB pin different to the CS pin and the multi-function
pin is used for receiving a feedback signal corresponding to a voltage of an output terminal of the power supply;

an auxiliary winding;
a first circuit coupled between the multi-function pin and the auxiliary winding, wherein the first circuit has a diode; and
a second circuit coupled between the multi-function pin and a ground line, wherein the second circuit has a thermistor coupled
between the multi-function pin and the ground line, a resistance of the second circuit is varied with a resistance of the
thermistor, and the resistance of the second circuit is used for determining whether an over temperature protection signal
is enabled;

wherein when a voltage signal of the CS pin exceeds a value corresponding to the feedback signal, the power switch is turned
off, and when the power switch is turned off, the power controller detects a discharge time of the auxiliary winding through
the multi-function pin.

US Pat. No. 9,405,354

CONTROLLING METHOD, POWER CONTROLLER, AND POWER CONTROLLING METHOD

Leadtrend Technology Corp...

1. A controlling method utilized in a power supply comprising a switch and an inductive element, the controlling method comprising:
detecting an inductive current flowing through the inductive element;
determining the power supply is operated under a normal loading state or an overloaded state according to a feedback signal;
controlling a peak of the inductive current to be smaller than or equal to a constant magnitude;
controlling the switch to be operated in a first fixed frequency when the power supply is under the normal loading state and
operated in a second fixed frequency when the power supply is under the overloaded state, wherein the second fixed frequency
is higher than the first fixed frequency;

calculating a duration during which the power supply is operated under the overloaded state; and
ceasing the operation of the switch when the duration exceeds a tolerable duration;
wherein the tolerable duration is independent of variation of an operating frequency of the switch, and the operating frequency
of the switch increases according to the feedback signal from the first fixed frequency to the second fixed frequency.

US Pat. No. 9,755,421

CONTROL CIRCUIT APPLIED TO A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A control circuit applied to a power converter, the control circuit having a brown-out protection, an over-temperature
protection, and an over-voltage protection, the control circuit comprising:
a multi-functional pin for receiving an auxiliary current generated by an auxiliary winding of the power converter, and an
input current;

a zero-crossing signal generator for generating a zero-crossing signal according to the auxiliary current;
an over-voltage detector for generating an over-voltage signal according to the auxiliary current;
a sample and hold unit coupled to the multi-functional pin for generating a sampling current corresponding to a positive half
cycle of an alternating current voltage according to the input current received by the multi-functional pin when the alternating
current voltage is at the positive half cycle and the power switch is turned on;

and a subtractor coupled to the multi-functional pin and the sample and hold unit for subtracting the input current received
by the multi-functional pin according to the sampling current to filter the auxiliary current when the power switch is turned
off, wherein the sampling current is substantially equal to the input current;

wherein the control circuit generates a switch control signal to a power switch of the power converter according to the zero-crossing
signal, or generates an over-voltage protection signal to the power switch according to the over-voltage signal.

US Pat. No. 9,641,086

OSCILLATOR APPLIED TO A CONTROL CIRCUIT OF A POWER CONVERTER AND CONTROL METHOD THEREOF

Leadtrend Technology Corp...

1. An oscillator applied to a control circuit of a power converter, the oscillator comprising:
a compensation module for outputting or sinking an adjustment current according to a compensation voltage corresponding to
a load of a secondary side of the power converter, a direct current (DC) voltage of a primary side of the power converter,
and a reference voltage, wherein the compensation module comprises:

a voltage-to-current converting unit for generating a compensation current according to the compensation voltage; and
an adjustment current generation unit coupled to the voltage-to-current converting unit for outputting or sinking the adjustment
current according to the compensation current, the DC voltage, and the reference voltage, wherein when the DC voltage is less
than the reference voltage, the adjustment current generation unit outputs the adjustment current, and when the DC voltage
is greater than the reference voltage, the adjustment current generation unit sinks the adjustment current; and

an oscillation module for outputting a clock signal according to the compensation voltage, a control voltage within the control
circuit, and the adjustment current, wherein the control circuit generates a gate control signal to a power switch of the
primary side of the power converter according to the clock signal;

wherein when the compensation voltage is less than a first predetermined voltage, a frequency of the gate control signal is
a first fixed value, and when the compensation voltage is between the first predetermined voltage and a second predetermined
voltage and greater than the second predetermined voltage, the frequency is varied with the compensation voltage.

US Pat. No. 9,046,382

POWER CONTROL CIRCUITS AND METHODS

Leadtrend Technology Corp...

1. A power control circuit for controlling a power supply comprising:
a clock generator for providing a clock signal for substantially determining switching cycles of the power supply;
a phase controller for generating a burst signal having a period not smaller than a period of a group reference signal according
to phases of the group reference signal and phases of a burst initiation signal for switching the power supply to a non-switching
state or a switching state; and

a power limiter for limiting a power output of the power supply in every switching cycle within a burst up duration not smaller
than the period of the group reference signal after the power supply is switched from the non-switching state to the switching
state;

wherein the burst initiation signal is generated according to the power output of the power supply.

US Pat. No. 9,621,055

CONTROLLER WITH LEAKAGE CURRENT PROTECTION OF A DIODE AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A controller with leakage current protection of a diode, wherein the diode is applied to a secondary side of a power converter,
the controller comprising:
a comparison unit for receiving a compensation voltage, and outputting a corresponding selection signal according to the compensation
voltage and a threshold;

a reference voltage generation unit for outputting a corresponding reference voltage range according to the corresponding
selection signal;

a time out signal generation unit for determining a corresponding time out according to the corresponding selection signal,
and generating a corresponding time out signal when a voltage corresponding to an auxiliary winding of the power converter
has no peak to cross an upper limit of the corresponding reference voltage range during the corresponding time out; and

a gate signal generation unit for entering the leakage current protection or a quasi-resonant mode according to the corresponding
time out signal.

US Pat. No. 9,584,030

CONTROLLER FOR ELIMINATING ACOUSTIC NOISE OF A POWER CONVERTER AND RELATED METHOD THEREOF

Leadtrend Technology Corp...

1. A controller for eliminating acoustic noise of a power converter, the controller comprising:
a feedback pin for receiving a feedback voltage from a secondary side of the power converter, wherein the feedback voltage
corresponds to an output voltage of the secondary side of the power converter;

a current detection pin for generating a detection voltage according to a current flowing through a primary side of the power
converter and a resistor;

a burst mode signal generation module coupled to the feedback pin for generating a burst mode signal according to a first
reference voltage and the feedback voltage, or according to a second reference voltage and the feedback voltage, wherein the
burst mode signal generation module comprises:

a first comparator for generating the burst mode signal according to the first reference voltage and the feedback voltage;
a second comparator for generating the burst mode signal according to the second reference voltage and the feedback voltage;
and

a control unit coupled to the gate signal generation unit for detecting a frequency corresponding to the gate control signal,
wherein when the frequency is greater than a predetermined frequency, the control unit controls the first comparator to generate
the burst mode signal according to the first reference voltage and the feedback voltage, when the frequency is less than the
predetermined frequency, the control unit controls the second comparator to generate the burst mode signal according to the
second reference voltage and the feedback voltage, and the second reference voltage is greater than the first reference voltage;

a gate signal generation unit coupled to the burst mode signal generation module for generating a gate control signal corresponding
to a burst mode of the power converter to a power switch of the primary side of the power converter according to the burst
mode signal, wherein the power switch is turned on according to the gate control signal; and

a turning-on time generation unit coupled to the burst mode signal generation module, the current detection pin, and the gate
signal generation unit for determining a turning-on time of the power converter in the burst mode of the power converter according
to the first reference voltage and the detection voltage, or according to the second reference voltage and the detection voltage.

US Pat. No. 9,917,504

SYNCHRONOUS RECTIFIER APPLIED TO A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A synchronous rectifier applied to a power converter, comprising:
a gate coupling effect suppressing unit for suppressing an induced voltage coupled to a gate of a metal-oxide-semiconductor
transistor coupled to a secondary side of the power converter to ensure that the metal-oxide-semiconductor transistor is turned
off when the power converter operates in a start-up condition and a power switch of a primary side of the power converter
is turned on, wherein when the power converter operates in the start-up condition, a driving voltage of the secondary side
of the power converter for driving the synchronous rectifier is not enough to drive the synchronous rectifier;

a dead time control unit for determining a dead time according to a predetermined voltage; and
a gate driving unit for generating a gate control signal controlling turning-on and turning-off of the metal-oxide-semiconductor
transistor according to the dead time.

US Pat. No. 9,564,814

CONTROLLER FOR ADJUSTING AN OUTPUT VOLTAGE OF A POWER CONVERTER AND RELATED METHOD THEREOF

Leadtrend Technology Corp...

1. A controller for adjusting an output voltage of a power converter, the controller comprising:
a gate control signal generation circuit for generating a gate control signal to a power switch of a primary side of the power
converter according to a reference voltage and a plurality of signals corresponding to the primary side and a second side
of the power converter;

a feedback signal detection module coupled to the primary side of the power converter for generating a logic signal according
to a voltage corresponding to an auxiliary voltage generated by an auxiliary winding of the primary side of the power converter
and a first reference voltage of a first reference voltage group, wherein the feedback signal detection module comprises:

a sampling circuit for sampling the voltage;
a multiplexer for outputting the first reference voltage from the first reference voltage group according to a first logic
signal; and

a first comparator having a first terminal coupled to the sampling circuit for receiving the voltage, a second terminal coupled
to the multiplexer for receiving the first reference voltage, and a third terminal for outputting the logic signal, wherein
the first comparator outputs the logic signal according to the voltage and the first reference voltage; and

a reference voltage generation module coupled to the feedback signal detection module for generating the reference voltage
to the gate control signal generation circuit according to the logic signal;

wherein the power switch adjusts the output voltage of the second side of the power converter according to the gate control
signal.

US Pat. No. 9,979,304

SAMPLE-AND-HOLD CIRCUIT FOR GENERATING A VARIABLE SAMPLE SIGNAL OF A POWER CONVERTER AND METHOD THEREOF

Leadtrend Technology Corp...

1. A sample-and-hold circuit for generating a variable sample signal of a power converter, comprising:a first voltage generator for generating a first voltage according to a first reference current;
a second voltage generator for generating a second voltage, wherein the second voltage corresponds to a turning-on time of a power switch of the power converter, and the second voltage generator comprises:
a first current source for providing a first reference current, wherein the first reference current is equal to K multiple of a difference between the first reference current and a peak current, wherein K>1, and the peak current corresponds to a peak value of a detection voltage determined by a primary side current flowing through the power switch of the power converter and a resistor;
a first switch coupled to the first current source for being turning-on and turning-off according to a first turning-on signal;
a first capacitor coupled between the first switch and ground, wherein when the first switch is turned on according to the first turning-on signal, the first reference current charges the first capacitor to generate the second voltage, wherein a capacitance of the first capacitor is equal to a capacitance of a second capacitor comprised in the first voltage generator; and
a second switch coupled to the first switch, a comparator, and the ground for being turning-on and turning-off according to a second turning-on signal, wherein after the first turning-on signal and a third turning-on signal are disabled, the second switch is turned on according to the second turning-on signal to erase residual charges stored in the first capacitor; and
the comparator for generating a sample signal to a control circuit within the power converter according to the first voltage and the second voltage.

US Pat. No. 9,843,264

CONTROLLER OF A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A controller of a power converter, wherein the power converter is applied to a Universal Serial Bus (USB) power delivery
adapter system, the controller comprising:
a sample-and-hold unit for sampling a voltage to generate a sampling voltage during each period of a gate control signal,
wherein the sampling voltage corresponds to an output voltage of the power converter; and

an adjustment unit coupled to the sample-and-hold unit, wherein the adjustment unit comprises:
a current generation module for generating a corresponding current according to the sampling voltage and a compensation voltage,
wherein the compensation voltage is generated directly according to the output voltage of the power converter; and

a control voltage generation module for generating a control voltage according to the corresponding current and a fixed current,
wherein the control voltage is used for determining a frequency of the gate control signal.

US Pat. No. 9,973,100

SYNCHRONOUS RECTIFIER APPLIED TO A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A synchronous rectifier applied to a power converter, comprising:a power supply module for generating a supply current according to an induced voltage generated from a secondary side of the power converter, wherein the supply current is used for establishing a supply voltage, and the induced voltage corresponds to a control signal of a power switch of a primary side of the power converter, wherein the power supply module comprises:
a high voltage switch for generating the supply current according to the induced voltage;
a voltage limit unit coupled to a synchronous switch and the high voltage switch for limiting the induced voltage to a predetermined voltage to protect a gate terminal of the high voltage switch;
a gate clamping unit coupled to the voltage limit unit and the high voltage switch for clamping a voltage between the gate terminal of the high voltage switch and a source terminal of the high voltage switch; and
a diode coupled to the gate clamping unit, the high voltage switch, and a gate driving unit for preventing the supply voltage from reversing to the gate clamping unit and the high voltage switch when the high voltage switch is turned off;
a control module coupled to the power supply module for turning on or turning off the power supply module according to the supply voltage; and
the gate driving unit coupled to the power supply module for generating a gate control signal controlling turning-on and turning-off of the synchronous switch of the secondary side of the power converter according to the induced voltage, wherein the supply voltage is used for driving the gate driving unit.

US Pat. No. 10,186,972

CONTROLLER APPLIED TO A SECONDARY SIDE OF A POWER CONVERTOR AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A controller applied to a secondary side of a power convertor, comprising:a sampling/tracking circuit coupled to the secondary side of the power convertor for generating a sampling value corresponding to an output voltage of the power convertor when a sampling signal is enabled, and generating a tracking value corresponding to the output voltage; and
a comparator coupled to the sampling/tracking circuit for generating a warning signal to a primary-side regulation (PSR) controller of the power converter according to the sampling value and the tracking value during an enabling period of a tracking signal, wherein when the tracking value is less than the sampling value, the comparator generates the warning signal to the primary-side regulation controller;
wherein the primary-side regulation controller adjusts a frequency of a gate control signal corresponding to a power switch of a primary side of the power convertor according to the warning signal, and the sampling signal and the tracking signal are not enabled simultaneously.

US Pat. No. 10,694,602

RIPPLE SUPPRESSOR

Leadtrend Technology Corp...

1. A ripple suppressor, comprising:a constant current generation circuit coupled to a light-emitting diode chain for generating a detection voltage, and generating a constant current to the light-emitting diode chain; and
a voltage regulation circuit coupled to the light-emitting diode chain and the constant current generation circuit for making the constant current generation circuit generate the constant current according to the detection voltage and a compensation value, or making the constant current generation circuit generate the constant current according to the detection voltage, wherein the compensation value is changed with an average voltage generated by the voltage regulation circuit, and the average voltage corresponds to a voltage of an end of the light-emitting diode chain.

US Pat. No. 10,186,973

MULTI-MODE CONTROLLER OF A POWER CONVERTER SWITCHED BY ZERO-CROSSING SIGNAL AND CONTINUOUS-CONDUCTION MODE SIGNAL AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A multi-mode controller applied to a power converter, comprising:a detection range generation module for generating a comparison voltage, according to a reference current, and generating a detection signal according to the comparison voltage and a first reference voltage, wherein the detection range generation module comprises:
a current source for providing the reference current;
a capacitor coupled between the current source and ground for generating the comparison voltage according to the reference current;
a metal-oxide-semiconductor transistor coupled to two terminals of the capacitor;
a first comparison unit for generating the detection signal according to the comparison voltage and the first reference voltage;
a second comparison unit for generating the continuous-conduction mode signal according to the comparison voltage and the second reference voltage; and
a logic unit for turning on the metal-oxide-semiconductor transistor to disable the detection signal according to the continuous-conduction mode signal or the zero-crossing signal; and
a gate signal generation unit, wherein when the detection signal is disabled by a zero-crossing signal, the gate signal generation unit generates a gate control signal corresponding to a quasi-resonant mode of the power converter according to the zero-crossing signal, and when the detection signal is disabled by a continuous-conduction mode signal generated by the detection range generation module further according to the comparison voltage and a second reference voltage, the gate signal generation unit generates the gate control signal corresponding to a continuous-conduction mode of the power converter according to the continuous-conduction mode signal.

US Pat. No. 9,577,515

CONTROLLER FOR GENERATING JITTERS IN A QUASI RESONANT MODE AND METHOD FOR GENERATING JITTERS IN A QUASI RESONANT MODE

Leadtrend Technology Corp...

1. A controller for generating jitters in a quasi resonant mode, the controller comprising: a feedback pin for receiving a
feedback voltage from a secondary side of a power converter; a voltage generation unit for generating a first voltage according
to the feedback voltage and a pulse, wherein the voltage generation unit comprises:
a switch for being turned on according to the pulse, wherein when the switch is turned on, the first voltage is pulled down
to ground;

a variable current source for periodically increasing a charging current of the variable current source with time after decreasing
the charging current of the variable current source with time, or periodically decreasing the charging current of the variable
current source with time after increasing the charging current of the variable current source according to the feedback voltage
and a digital signal; and

a capacitor coupled between the variable current source and the ground for generating the first voltage according to the charging
current when the switch is turned off;

a pulse generator for generating the pulse when a control signal controlling a power switch of a primary side of the power
converter is enabled; and

a comparator for controlling enabling and disabling of a switching signal according to the first voltage and a variable reference
voltage, wherein the variable reference voltage is periodically decreased with time after being increased with time, or periodically
increased with time after being decreased with time within a predetermined voltage range according to the digital signal.

US Pat. No. 10,667,356

DIMMING CONTROLLERS AND DIMMING METHODS CAPABLE OF RECEIVING PWM DIMMING SIGNAL AND DC DIMMING SIGNAL

LEADTREND TECHNOLOGY CORP...

1. A dimming controller for dimming a light-emitting device, comprising:an input node for receiving a dimming signal used for dimming the light-emitting device;
a type identifier connected to the input node, for identifying whether the dimming signal is of DC or of PWM; and
a multiplexer with an output, the multiplexer controlled by the type identifier and configured to provide at least a DC signal path and a PWM signal path both coupled between the input node and the output;
wherein the type identifier makes the multiplexer enable the DC signal path and interrupt the PWM signal path if the dimming signal is identified as of DC, and makes the multiplexer enable the PWM signal path and interrupt the DC signal path if the dimming signal is identified as of PWM.

US Pat. No. 10,199,942

CONTROLLER AND POWER SUPPLY

Leadtrend Technology Corp...

1. A power supply, comprising:a transformer, having a primary winding and an auxiliary winding;
a power switch coupled to the primary winding;
a sensing resistor, having a first terminal coupled to a grounding line and a second terminal coupled to the power switch;
a controller, having a multi-function terminal coupled to the sensing resistor; and
a diode and a first resistor, coupled between the auxiliary winding and the multi-function terminal;
wherein, when the power switch is turned on, the controller through the multi-function terminal detects a current through the power switch, and when the power switch is turned off, the controller detects a voltage of the multi-function terminal, and determines to trigger a protection mechanism if the voltage of the multi-function terminal is over a reference voltage.

US Pat. No. 10,056,823

PROTECTION CIRCUIT APPLIED TO AN ALTERNATING CURRENT POWER SOURCE AND RELATED PROTECTION METHOD THEREOF

Leadtrend Technology Corp...

1. A protection circuit applied to an alternating current (AC) power source, comprising:a sample-and-hold unit for sampling a peak value of a direct current (DC) voltage during each period of a corresponding AC voltage, wherein the AC power source provides the AC voltage;
a detection unit coupled to the sample-and-hold unit for generating a detection signal when the DC voltage crosses a reference voltage derived from the peak value within a same period of the AC voltage, wherein the reference voltage is changed with the DC voltage and corresponds to the AC voltage; and
a discharge signal generation unit coupled to the detection unit for generating a count signal when the discharge signal generation unit does not receive the detection signal within a predetermined time of a period of the AC voltage, accumulating the count signal, and generating a discharge signal to a discharge unit when a number of accumulated count signals is greater than a predetermined value;
wherein the discharge unit is used for discharging an X capacitor according to the discharge signal.

US Pat. No. 10,580,862

HIGH-VOLTAGE SEMICONDUCTOR DEVICES WITH IMPROVED EAS AND RELATED MANUFACTURING METHOD THEREOF

LEADTREND TECHNOLOGY CORP...

1. A high-voltage semiconductor device with improved EAS, comprising:a main high-voltage switch device, comprising:
a plurality of switch cells, arranged to form a first array on a semiconductor substrate, wherein each switch cell has a first cell width; and
a current-sense device, comprising:
a plurality of sense cells, arranged to form a second array on the semiconductor substrate, wherein each sense cell has a second cell width larger than the first cell width;
wherein the switch cells and the sense cells share a common gate electrode and a common drain electrode.

US Pat. No. 10,560,029

CONTROLLER FOR INCREASING EFFICIENCY OF A POWER CONVERTER AND A RELATED METHOD THEREOF

Leadtrend Technology Corp...

1. A controller for increasing efficiency of a power converter, the controller comprising:an enable signal generation unit electrically connected to a direct current (DC) input terminal of a primary side of the power converter through a high voltage pin of the controller, wherein the enable signal generation unit is used for generating an enable signal corresponding to a duty cycle of a gate control signal according to a DC input voltage of the DC input terminal and a feedback voltage corresponding to a secondary side of the power converter, and the feedback voltage corresponds to an output voltage of the secondary side of the power converter; and
a gate signal generation unit having two transistors in parallel, wherein a first terminal of a first transistor of the two transistors and a first terminal of a second transistor of the two transistors are coupled to ground, a second terminal of the first transistor is coupled to a gate pin of the controller through a switch comprised in the gate signal generation unit, a second terminal of the second transistor is directly coupled to the gate pin, and a control terminal of the first transistor and a control terminal of the second transistor receive a pulse width modulation signal;
wherein the gate signal generation unit utilizes the enable signal to control turning-on and turning-off of the switch to change a sink current flowing through the gate pin of the controller, wherein the gate pin is coupled to a power switch of the primary side of the power converter, and the gate signal generation unit is further used for generating a gate control signal to the power switch.

US Pat. No. 10,204,896

VERTICAL DOUBLE DIFFUSION METAL-OXIDE-SEMICONDUCTOR POWER DEVICE

Leadtrend Technology Corp...

1. A vertical double diffused metal-oxide-semiconductor (VDMOS) power device with thermal sensitivity unit, comprising:a VDMOS power transistor, comprising:
a first metal layer;
a substrate layer with first conductivity type formed on the first metal layer;
an epitaxy layer with first conductivity type formed on the substrate layer;
a second metal layer; and
a plurality of first polysilicon layers, wherein each first polysilicon layer of the plurality of first polysilicon layers corresponds to a first oxide layer, a first doping well and a second doping well with second conductivity type, a first doped region and a second doped region with first conductivity type, and a second oxide layer, wherein the first oxide layer is formed on the epitaxy layer, the first doping well and the second doping well are formed within the epitaxy layer, the first doped region and the second doped region are formed within the first doping well and the second doping well respectively, the each first polysilicon layer is formed on the first oxide layer, the second oxide layer covers the each first polysilicon layer, and the second metal layer is formed on the first doping well, the second doping well, the first doped region, the second doped region, and the second oxide layer; and
at least one thermal sensitivity unit formed on the epitaxy layer, wherein the at least one thermal sensitivity unit is used for detecting a temperature of the VDMOS power transistor when the VDMOS power transistor operates, and the VDMOS power transistor and the at least one thermal sensitivity unit share a same process, wherein each thermal sensitivity unit of the at least one thermal sensitivity unit comprises:
a second polysilicon layer formed on a third oxide layer; and
a doped region formed within the second polysilicon layer;
wherein the third oxide layer is formed on a deep doping well with second conductivity type, and the deep doping well is formed within the epitaxy layer.

US Pat. No. 10,199,948

STANDBY POWER CONTROL FOR A FLYBACK USB DEVICE USING PRIMARY SIDE FREQUENCY AND DATA PORT SENSING

Leadtrend Technology Corp...

1. A secondary controller applied to a secondary side of a power converter, comprising:a detector for detecting a first signal and a second signal of a universal serial bus (USB) device and a frequency of a synchronization signal corresponding to a primary side of the power converter; and
a standby signal generation circuit coupled to the detector for delaying a first predetermined time to generate a standby signal to a primary controller of the primary side of the power converter when the detector fails to detect the first signal and the second signal, and the frequency of the synchronization signal is less than a first predetermined frequency, wherein the primary controller enters a standby mode according to the standby signal.

US Pat. No. 10,644,584

POWER CONTROLLER AND RELEVANT CONTROL METHOD CAPABLE OF PROVIDING OPEN-CIRCUIT PROTECTION

LEADTREND TECHNOLOGY CORP...

1. A power controller in use of a power supply with a transformer including a primary winding, a secondary winding and an auxiliary winding, wherein the power supply includes a power switch connected in series with the primary winding between an input voltage and an input ground, and the auxiliary winding has a ground end and a floating end, where the ground end is for connecting to the input ground, the power controller comprising:a PWM signal generator for providing a PWM signal to control the power switch and to regulate an output voltage of the power supply, wherein the PWM signal determines an ON time and an OFF time of the power switch;
a feedback node connected via a resistor to the floating end; and
a deviation detector connected to the feedback node for detecting a winding voltage at the floating end and checking if the winding voltage changes to have within the ON time a second voltage different from a first voltage at a first time point within the ON time and a voltage difference between the second and first voltages fits a first predetermined condition during the ON time, wherein when the voltage difference fits the first predetermined condition during the ON time, the deviation detector asserts an open protection signal to keep the power switch turned OFF, so as to provide open-circuit protection for an open circuit occurring between the ground end and the input ground.

US Pat. No. 10,571,986

POWER DELIVERY CONTROLLER APPLIED TO A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A power delivery controller applied to a power converter, comprising:a voltage compensation circuit for coupling to configuration channel pins of a universal serial bus (USB) type-C cable, and generating a compensation reference voltage, receiving a response signal through the configuration channel pins, and generating a response voltage corresponding to the response signal when an electronic device coupled to the USB type-C cable generates the response signal corresponding to a biphase mark coding (BMC) signal, wherein the response voltage and the compensation reference voltage have information relative to an internal resistor of the USB type-C cable, and the biphase mark coding signal and the response signal are clock signals; and
a comparator coupled to the voltage compensation circuit for generating a comparison signal according to the response voltage and the compensation reference voltage, wherein the power converter transmits power to the electronic device according to a specification corresponding to universal serial bus power delivery (USB-PD) after the comparator generates the comparison signal.

US Pat. No. 10,381,935

SAMPLE-AND-HOLD CIRCUIT FOR GENERATING A VARIABLE SAMPLE SIGNAL OF A POWER CONVERTER AND METHOD THEREOF

Leadtrend Technology Corp...

1. A sample-and-hold circuit for generating a variable sample signal of a power converter, comprising:a first voltage generator for generating a first voltage according to a first predetermined delay time and a voltage corresponding to an auxiliary winding of the power converter;
a second voltage generator for generating a second voltage according to K multiple of a discharge time of a secondary side of the power converter corresponding to a previous period of the power converter and the voltage corresponding to the auxiliary winding, wherein K<1; and
a stabilization capacitor being electrically connected to the first voltage generator and the second voltage generator;
wherein when a sum of the K multiple of the discharge time of the secondary side and a second predetermined delay time leads a first valley of the voltage corresponding to a current period of the power converter, the second voltage generator outputs the second voltage, and the stabilization capacitor stabilizes the second voltage; and when the sum of the K multiple of the discharge time of the secondary side and the second predetermined delay time lags the first valley, the first voltage generator outputs the first voltage, and the stabilization capacitor stabilizes the first voltage.

US Pat. No. 10,305,379

CONTROL CIRCUIT FOR COMPENSATING OUTPUT LOSS OF A POWER CONVERTER AND METHOD THEREOF

Leadtrend Technology Corp...

1. A control circuit for compensating output loss of a power converter, the control circuit comprising:a sampling voltage generator, comprising:
a sampling time signal generator for generating a sampling time signal according to a first reference current and a second reference current; and
a voltage generator coupled to the sampling time signal generator for generating a sampling voltage corresponding to a detection voltage according to the detection voltage and the sampling time signal, wherein the sampling voltage is transmitted to a compensation signal generator;
a time-to-voltage converter for generating a corresponding voltage to the compensation signal generator according to a period of a gate control signal controlling a power switch of a primary side of the power converter and a discharge time of a secondary side of the power converter; and
the compensation signal generator coupled to the sampling voltage generator and the time-to-voltage converter for generating a compensation signal compensating the output loss according to the sampling voltage and the corresponding voltage.

US Pat. No. 10,700,595

CONTROLLER FOR EXTENDING A PROTECTION PERIOD OF A POWER CONVERTER AND OPERATIONAL METHOD THEREOF

Leadtrend Technology Corp...

1. A controller for extending a protection period of a power converter, comprising:a delay circuit coupled to a supply voltage pin of the controller, wherein when the power converter enters a protection mode, the delay circuit is enabled, receives a supply voltage through the supply voltage pin, and extends the protection period corresponding to the protection mode according to the supply voltage, and the delay circuit comprises:
a first current source coupled to the supply voltage pin for generating a first discharge current according to a protection signal corresponding to the protection mode and the supply voltage when the power converter enters the protection mode;
a delayer for generating a delay enabling signal according to the protection signal and a detection voltage of a primary side of the power converter, wherein the delay enabling signal corresponds to a predetermined delay time; and
a second current source coupled to the delayer and the supply voltage pin for generating a second discharge current according to the delay enabling signal;
wherein the supply voltage is determined by the first discharge current, a capacitor of the primary side of the power converter, and a charge current corresponding to an input terminal of the primary side of the power converter, or determined by the first discharge current, the second discharge current, the capacitor, and the charge current.

US Pat. No. 10,361,636

SYNCHRONOUS RECTIFIER APPLIED TO A POWER CONVERTER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A synchronous rectifier applied to a power converter, comprising:a control signal generation circuit for generating a control signal corresponding to a previous period of a secondary side of the power converter according to a detection signal corresponding to the previous period of a-the secondary side, a first reference voltage, and a second reference voltage when the secondary side of the power converter is turned on, wherein the control signal corresponding to the previous period corresponds to a discharge time of the previous period;
a pre-attenuation circuit coupled to the control signal generation circuit, wherein the pre-attenuation circuit receives the control signal corresponding to the previous period, and is used for pre-attenuating a gate control signal corresponding to a current period of the secondary side according to the control signal of the previous period and generating a pre-attenuation signal corresponding to the current period; and
a gate driving circuit coupled to the control signal generation circuit and the pre-attenuation circuit for driving the gate control signal corresponding to the current period according to the control signal corresponding to the current period, and stopping driving the gate control signal corresponding to the current period according to the pre-attenuation signal corresponding to the current period; and a pre-attenuation signal generator coupled to the control signal generation circuit for generating the pre-attenuation signal corresponding to the current period according to the control signal corresponding to the previous period; a pulse generator coupled to the pre-attenuation signal generator for generating a pre-attenuation pulse corresponding to the current period according to the pre-attenuation signal corresponding to the current period; and a pull-down circuit coupled to the pulse generator and the pre-attenuation signal generator for pre-attenuating the gate control signal corresponding to the current period according to the pre-attenuation pulse corresponding to the current period.

US Pat. No. 10,691,189

LINE-VOLTAGE DETECTION METHOD, POWER CONTROLLER AND POWER SUPPLY WITH BROWN-OUT PROTECTION AND BROWN-IN MECHANISM

LEADTREND TECHNOLOGY CORP...

1. A line-voltage detection method for a power controller with a high-voltage node connected via a current-limiting resistor to a line voltage generated by rectifying an alternating-current input voltage, wherein the power controller includes a high-voltage startup transistor, the line-voltage detection method comprising:dividing a first input voltage at the high-voltage node to provide a fraction result;
providing an offset current flowing through the high-voltage startup transistor and the current-limiting resistor in response to the fraction result; and
stopping the offset current in response to the fraction result when the offset current flows through the high-voltage startup transistor and the current-limiting resistor.

US Pat. No. 10,673,350

MULTIPLE OUTPUT RECTIFIER AND OPERATION METHOD THEREOF

Leadtrend Technology Corp...

1. A multiple output rectifier, comprising:a comparator-based active rectification circuit for generating and outputting a plurality of output voltages within a same half period of an input voltage, wherein within the same half period, the active rectification circuit generates a corresponding comparison signal according to the input voltage and each output voltage of the plurality of output voltages, generates a corresponding turning-on signal according to the corresponding comparison signal and a control signal, and generates and outputs the each output voltage according to the corresponding turning-on signal, wherein the corresponding comparison signal corresponds to a predetermined time interval within the same half period, and the each output voltage is less than the input voltage within the predetermined time interval.

US Pat. No. 10,666,153

ACTIVE CLAMP FLYBACK CONVERTERS AND CONTROL METHODS THEREOF

LEADTREND TECHNOLOGY CORP...

10. A power converter using an active-clamp flyback topology, comprising:a transformer with a primary winding;
a low-side switch for connecting the primary winding to a first power line;
a high-side switch connected in series with a capacitor to form an active-clamp circuit connected in parallel with the primary winding; and
a control circuit, configured to control the high-side switch and the low-side switch in response to a compensation signal and a current-sense signal;
wherein the control circuit selectively operates the power converter in one of operation modes including a flyback mode;
when operated in the flyback mode, the control circuit switches the low-side switch to generate consecutive switching cycles including a normal flyback cycle and a modified flyback cycle;
during a normal flyback cycle, the control circuit constantly turns the high-side switch OFF;
during a modified flyback cycle, the control circuit turns ON the high-side switch after a blanking time to perform zero-voltage switching for the low-side switch; and
the control circuit determines the blanking time in response to the compensation signal.

US Pat. No. 10,554,139

SYNCHRONOUS RECTIFIER APPLIED TO A SECONDARY SIDE OF A POWER CONVERTER AND OPERATIONAL METHOD THEREOF

Leadtrend Technology Corp...

1. A synchronous rectifier applied to a secondary side of a power converter, comprising:a forbidden turning-on time generation circuit coupled to the secondary side of the power converter for generating a forbidden turning-on time corresponding to the secondary side according to a synchronous signal of the secondary side;
a green mode signal generation circuit coupled to the forbidden turning-on time generation circuit and the secondary side for enabling a green mode signal when the forbidden turning-on time is greater than a reference value by at least one time, and disabling the green mode signal when the forbidden turning-on time is continuously less than the reference value by a predetermined number of times, wherein the reference value is changed with an output voltage of the secondary side; and
a controller coupled to the green mode signal generation circuit and the secondary side for entering a green mode when the green mode signal is enabled, and leaving the green mode when the green mode signal is disabled, wherein when the controller leaves the green mode, the controller generates a driving signal driving a synchronous switch of the secondary side according to the synchronous signal.

US Pat. No. 10,361,635

METHOD OF CONTROLLING A POWER CONVERTER SWITCHED BY A ZERO CROSSING SIGNAL AND A CONTINUOUS CONDUCTION SIGNAL

Leadtrend Technology Corp...

1. An operation method of a multi-mode controller applied to a power converter, wherein the multi-mode controller comprises a detection range generation module and a gate signal generation unit, and the detection range generation module comprises a current source, a capacitor, a metal-oxide-semiconductor transistor, a first comparison unit, a second comparison unit, and a logic unit, the operation method comprising:the current source providing a reference current;
the capacitor generating a comparison voltage according to the reference current;
the first comparison unit generating a detection signal according to the comparison voltage and a first reference voltage;
the second comparison unit generating a continuous-conduction mode signal according to the comparison voltage and a second reference voltage;
the logic unit turning on the metal-oxide-semiconductor transistor to disable the detection signal according to the continuous-conduction mode signal or a zero-crossing signal;
the gate signal generation unit generating a gate control signal corresponding to a quasi-resonant mode of the power converter according to the zero-crossing signal when the detection signal is disabled by the zero-crossing signal; and
the gate signal generation unit generating the gate control signal corresponding to the continuous-conduction mode of the power converter according to the continuous-conduction mode signal when the detection signal is disabled by the continuous-conduction mode signal according to the comparison voltage and the second reference voltage.

US Pat. No. 10,269,897

POWER METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTOR DEVICE WITH THREE-DIMENSIONAL SUPER JUNCTION AND FABRICATION METHOD THEREOF

Leadtrend Technology Corp...

1. A power metal-oxide-semiconductor field-effect transistor (MOSFET) device with three-dimensional super junction, comprising:a first metal layer;
a substrate formed on the first metal layer;
an epitaxy layer formed on the substrate;
a plurality of first trench wells formed in the epitaxy layer;
a plurality of body structure layers, wherein a body structure layer corresponding to each first trench well is formed on the each first trench well and in the epitaxy layer, and a part of a depletion region is formed between each first trench well and the epitaxy layer and between the body structure layer and the epitaxy layer;
a plurality of second trench wells, wherein a second trench well corresponding to the each first trench well is formed under the each first trench well, and a rest part of the depletion region is formed between the second trench well and the epitaxy layer;
a plurality of polysilicon layers, wherein each polysilicon layer is formed on two adjacent body structure layers and the epitaxy layer, and the each polysilicon layer is covered by an oxide layer; and
a second metal layer formed on the plurality of body structure layers and a plurality of oxide layers;
wherein the substrate and the epitaxy layer have a first conductivity type, the plurality of first trench wells and the plurality of second trench wells have a second conductivity type, and the plurality of second trench wells are used for increasing a breakdown voltage of the power MOSFET device and reducing a conduction resistor of the power MOSFET device.