System General Corporation

Semiconductor Components Industries, LLC

Fairchild (taiwan) Corporation

Chou-Sheng Wang

Ta-Yung Yang

Ying-Chieh Su

Tse-Jen Tseng

Jhih-Da Hsu

Rui-Hong Lu

Pei-Sheng Tsu

Chia-Yo Yeh

Tien-Chi Lin

Yi-Min Hsu

Jian-Ming Fu

Eui-Soo Kim

Jenn-Yu G Lin

Zhibo Tao

Ju-Hyun Kim

Shih-Hung Hsieh

Chen-Hui Chan

Wei-Li Hsu

Chien-Chun Huang

Jui-Chien Wang

Jian Ming Fu

Synchronous rectifier gate voltage boost method and system. At least some of the example embodiments are methods of operating a power converter to create an output voltage, including storing energy in a field of a main transformer arranged for flyback operation, the storing during periods of time when a primary switch is conductive and current flows through a primary winding of the transformer; and then transferring energy from the field of the main transformer to the output voltage on a secondary side of the power converter; activating a secondary rectifier (SR) switch on the secondary side of the power converter during periods of time when the primary switch is non-conductive, the activating by: driving a gate of the SR switch without boost if the output voltage is above a first threshold; and driving the gate of the SR switch with boost if the output voltage is below the first threshold.

Synchronous rectifier gate voltage boost method and system

A protection circuit for a power converter is provided. The protection circuit includes a sensor circuit, a detection circuit and an initial protection circuit. The sensor circuit senses an output current of the power converter to generate a load signal. The detection circuit detects a voltage signal at a signal terminal of the connection port. The initial protection circuit compares the load signal with an initial-protection threshold. When the voltage signal at the signal terminal switches to a high level from a low level after the protection circuit is enabled, the power converter enters an initial protection mode and the initial protection circuit counts an initial period of a port-identification procedure. When the load signal is larger than the initial-protection threshold during the initial period of the port-identification procedure, the initial protection circuit generates a first protection signal to shut down the power converter.

Protection circuit and method for flyback power converter

A regulation circuit of a power converter for cable compensation according to the present invention comprises a signal generator generating a compensation signal in accordance with a synchronous rectifying signal. An error amplifier has a reference signal for generating a feedback signal in accordance with an output voltage of the power converter. The compensation signal is coupled to program the reference signal. The feedback signal is coupled to generate a switching signal for regulating an output of the power converter. The regulation circuit of the present invention compensates the output voltage without a shunt resistor to sense the output current of the power converter for reducing power loss.

Regulation circuit associated with synchronous rectifier providing cable compensation for the power converter and method thereof

A power converter and a control method therefor are provided. The power converter includes a transformer, a primary-side control circuit and a secondary-side control circuit. A primary side of the transformer receives an input voltage, and a secondary side of the transformer generates an output voltage. The primary-side control circuit controls a current switch of a primary winding and switching thereof. The secondary-side control circuit is disposed at the secondary side of the transformer. The secondary-side control circuit comprises a latch circuit. The latch circuit clamps a feedback signal and maintains a clamped status of the feedback signal when an fault event occurs. The primary-side control circuit stops switching the current switch of the primary winding when the feedback signal is clamped, and the latch releases the feedback signal when the output voltage is lower than a default latch voltage value.

Power converter and control method for fault event occurrence

An apparatus of programming an output of a programmable power adapter according to the present invention comprises a control circuit. The method according to the present invention sends a signal to a device. A resistor is coupled to the signal to determine the level of the signal. The resistor is installed in the device. The method according to the present invention checks the level of the signal in the programmable power adapter and determines an output voltage of the programmable power adapter in accordance with the level of the signal. The output voltage of the programmable power adapter is coupled to the device to provide a power for a load of the device.

Method and apparatus for selecting the output of programmable power adapter

The invention discloses a method for controlling a synchronous rectifier of a power converter and a control circuit using the same. The method includes the following steps. A control signal is generated to control a synchronous rectification transistor in response to an on-time of a switching signal, a level of a transformer voltage and an output voltage of the power converter. The switching signal is used for switching a transformer. The control signal is generated once the switching signal is turned off. A transformer signal is related to an input voltage of the power converter. The control signal is generated when the on-time of the switching signal is longer than a first time threshold.

Method for controlling synchronous rectifier of power converter and control circuit using the same

A control circuit and a method for controlling a power converter are provided. The method for controlling the power converter includes the following steps. A detection signal is received from the secondary side of the power transformer and a first switching signal is generated in accordance with the detection signal. A second switching signal is generated in accordance with the first switching signal. A voltage signal is generated in accordance with the second switching signal. A comparison signal is generated in accordance with the first switching signal and the second switching signal. The voltage signal and the comparison signal are compared for outputting a comparison result. A gate signal is generated in accordance with the detection signal and the comparison result to control on and off states of a synchronization switch.

Power converter and method for controlling power converter

A synchronous rectifying control circuit of a power converter is provided. The synchronous rectifying control circuit comprises a synchronous rectifying driver, a charge pump capacitor, and a capacitor. The synchronous rectifying driver is coupled to a transformer for generating a control signal to switch a transistor. The charge pump capacitor is coupled to a power source for generating a charge pump voltage. The capacitor is coupled to store the charge pump voltage. The transistor is coupled to the transformer and operated as a synchronous rectifier. The charge pump voltage is coupled to guarantee a sufficient driving capability for the control signal.

Synchronous rectifier control circuits of power converters

Method and apparatus for controlling a programmable power converter are provided. The method and apparatus generate a first power source and a second power source. The voltage level of the second power source is lower than the voltage level of the first power source. The first power source and the second power source provide a power supply for a control circuit. The control circuit will use the first power source as its power supply when the first power source is low. The control circuit will use the second power source as its power supply for saving the power when the first power source is high.

Method and apparatus for controlling programmable power converter with low standby power loss

A control circuit of a power converter is provided. The control circuit includes a switching circuit and a charge pump circuit. The switching circuit generates a switching signal for controlling the power converter. The charge pump circuit includes an oscillator for generating an oscillation signal synchronized with the switching signal. The oscillation signal is coupled to control a switch of the charge pump circuit for generating a voltage source.

Charge pump circuits having frequency synchronization with switching frequency of power converters

A synchronous rectifying circuit for a switching power converter is provided. The synchronous rectifying circuit includes a power transistor, a diode, and a control circuit. The power transistor and the diode are coupled to a transformer and an output of the power converter for rectification. The control circuit generates a drive signal to switch on the power transistor once the diode is forward biased. The control circuit includes a monitor circuit. The monitor circuit generates a monitor signal an off signal to switch off the power transistor in response to a pulse width of the drive signal for generating an off signal to switch off the power transistor. The monitor circuit further reduces the pulse width of the drive signal in response to a change of a feedback signal. The feedback signal is correlated to an output load of the power converter.

Method and apparatus to improve dynamic response of the synchronous rectifying for resonant power converters

A synchronous rectifier for a switching power converter is provided and includes a power transistor, a diode, and a control circuit. The power transistor and the diode are coupled to a transformer and an output of the power converter for the rectification. The control circuit generates a drive signal to switch on the power transistor once the diode is forward biased. The control circuit includes a phase-lock circuit. The phase-lock circuit generates an off signal to switch off the power transistor in response to a pulse width of the drive signal. The pulse width of the drive signal is shorter than a turned-on period of the diode. The phase-lock circuit further reduces the pulse width of the drive signal in response to a feedback signal. The feedback signal is correlated to an output load of the power converter.

Synchronous rectifier having phase lock circuit coupled to feedback loop for resonant power converters

A control circuit for a switching power converter is provided. The control circuit is installed between a secondary side and an output of the power converter and coupled to control a switching device. The control circuit includes a linear predict circuit, a reset circuit, a charge/discharge circuit, and a PWM circuit. The linear predict circuit is coupled to receive a linear predict signal from the secondary side for generating a charging signal. The reset circuit is couple to receive a resetting signal for generating a discharging signal. The charge/discharge circuit is coupled to receive the charging signal and the discharging signal for generating a ramp signal. The PWM circuit is coupled to receive the linear predict signal for enabling a switching signal and receive the ramp signal for resetting the switching signal.

High-side synchronous rectifier circuits and control circuits for power converters

An adaptive synchronous rectification control circuit and a control method are developed. The control circuit comprises an adaptive circuit that generates a reference signal in response to a detection signal of a power converter. A clamped circuit clamps the reference signal at a threshold voltage if the reference signal equals or is greater than the threshold voltage. A switching circuit generates a control signal to control a synchronous switch of the power converter in response to the detection signal and the reference signal. The control method generates the reference signal in response to the detection signal. The reference signal is clamped at the threshold voltage if the reference signal equals or is greater than the threshold voltage. The method further generates the control signal to control the synchronous switch of the power converter in response to the detection signal and the reference signal.

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Keelung, Taiwan

Chou-Sheng Wang