Richtek Technology Corporation

Jyun-Che Ho

Isaac Y Chen

Chien-Fu Tang

Yi-Wei Lee

Jiun-Hung Pan

Yu-Chang Chen

Chien-Hung Chen

Jo-Yu Wang

Pei-Kai Tseng

Yung-Chih Lai

Issac Y Chen

Jung-Pei Cheng

Wei-Hsu Chang

Tzu-Chen Lin

Kun-Yu Lin

Shao-Hung Lu

A power supply system with power factor correction, includes: an AC rectifier, a power factor correction (PFC) conversion circuit, an asymmetric half-bridge (AHB) flyback converter and a communication protocol power delivery (PD) interface. When a power level of an adapter output power is lower than a power threshold, and a converted voltage of a converted power is higher than a first voltage threshold, the communication protocol PD interface generates a disable signal to disable a PFC conversion of the PFC conversion circuit, when the PFC conversion is disabled, the PFC conversion circuit operates a bypass coupling operation, as thus, the converted voltage is equal to a rectified voltage of a rectified power.

Power supply system with power factor correction(PFC) and control method thereof

The invention provides a power conversion device, including: a voltage conversion stage, including a primary side for receiving a rectified voltage and a secondary side for generating a rectified voltage according to the rectified voltage, wherein the primary side includes a primary side switch; a switch control circuit having a startup status and a normal operation status, the switch control circuit being configured to operably provide a control signal to a control terminal of the primary side switch; a startup circuit, providing a current to the control terminal when the switch control circuit is in the startup status, to at least partially conduct the primary side switch; and a slow soft-startup circuit, wherein when the switch control circuit is in the startup status and the output voltage does not reach a predetermined voltage in a first predetermined time period, the slow soft-startup circuit reduces a total current quantity supplied to the control terminal in a second predetermined time period which is after the first predetermined time period.

Power conversion device, slow soft-startup circuit, and power conversion chip

A buck switching regulator includes: a power stage, which includes: an upper-gate switch, a lower-gate switch and an inductor, connected with one another at a switching node; and a supply control switch, controlling the power supply form an output terminal to a load. An overvoltage protection method includes the following steps: (A) sensing a voltage of the switching node, to obtain a switching node voltage; (B) determining whether an overvoltage event occurs in the switching node voltage; and (C) if it is determined yes in the step (B), outputting a protection signal. An overvoltage event is determined directly according to the switching node voltage, not directly according to the output voltage.

Overvoltage protection method and buck switching regulator having overvoltage protection function and control circuit thereof

A multi-phase switching regulator includes: a plurality of power stages, a plurality of pulse width modulation (PWM) controllers and a ramp signal setting circuit. The PWM controllers generate corresponding PWM signals for controlling corresponding power stages respectively according to an error signal related to an output voltage and a plurality of ramp signals corresponding to corresponding power stages respectively. The ramp signal setting circuit adjusts the ramp signal of the phase that is to be enabled or disabled according to the phase adjustment signal. Under a phase-cut operation, the ramp signal setting circuit causes a basis level of the ramp signal corresponding to the phase to be disabled to gradually change, thereby decreasing a duty ratio of the PWM signal corresponding to the phase to be disabled.

Multi-phase switching regulator and control circuit and control method thereof

An AC-to-DC power converter with a BJT as a power switch can set a base current of the BJT by a current setting resistor which is in the outside of a control integrated circuit. Since an output current and a recovery current of the BJT are injected into a sensing resistor, the AC-to-DC power converter can correctly detect an inductor current thereof from the sensing resistor.

AC-to-DC power converter and control method and control integrated circuit thereof

A control circuit of a LED driver utilizes a counter to acquire a cycle and a conduction time or a non-conduction time of an AC phase-cut voltage outputted by a TRIAC dimmer. A bleeding signal is determined according to the cycle and the conduction time or the non-conduction time and used for adjusting a bleeding current so as to avoid a flickering of the LED. The control circuit does not need extra pins for coupling a large capacitor, but the bleeding signal can be still acquired. Preferably, the present invention is suitable for an IC of low pin numbers.

Control circuit and method of a LED driver

A power converter includes a rectifier and a power factor corrector. The rectifier is to be coupled to an alternating current power source and is configured to output a rectified signal. The power factor corrector includes a correcting circuit and a control circuit. The correcting circuit receives the rectified signal and is configured to generate an output voltage based on the rectified signal and a driving signal. The control circuit is configured to generate a first to-be-compared signal based on the rectified signal, to generate a second to-be-compared signal based on the output voltage, to compare the first and second to-be-compared signals, and to generate the driving signal based on a result of comparison performed thereby.

Power converter and power factor corrector thereof

A control integrated circuit for a power factor correction converter has a pin for detecting an alternating-current information and a direct-current information of an input signal. The control integrated circuit comprises a signal peak detector for detecting a peak value of the input signal to the pin to obtain the direct-current information of the input signal. Since the alternating-current information and the direct-current information of the input signal can be obtained through the same pin, the pin count of the control integrated circuit can be decreased.

Signal peak detector and detection method, and control IC and method for a PFC converter

A switching power converting apparatus includes a voltage conversion module, a detecting unit, and a switching signal generating unit. The voltage conversion module converts an input voltage into an output voltage associated with a secondary side current, which flows through a secondary winding of a transformer and is generated based on a switching signal. The detecting unit generates a detecting signal based on the output voltage and a predetermined reference voltage. The switching signal generating unit generates the switching signal based on the detecting signal and an adjusting signal so that the secondary side current is gradually increased during a start period of the switching power converting apparatus.

Soft-start switching power converting apparatus with pulse-frequency modulation technique

An AC-to-DC power converting apparatus includes a power factor correction circuit generating a DC output voltage based on a rectified voltage obtained through rectifying an AC input voltage and on a PWM signal generated based on an adjustment current and a predetermined ramp signal. A multiplier-divider circuit includes: a ramp generating unit generating a ramp signal based on a clock signal and on a first detection voltage associated with the rectified voltage; a control unit generating a control signal based on the clock signal, the ramp signal, and a detection voltage generated based on the DC output voltage; and an output unit generating an adjustment signal based on an input signal associated with the rectified voltage and the control signal.

Multiplier-divider circuit and AC-to-DC power converting apparatus incorporating the same

A switching power converting apparatus includes a coil unit, a bipolar junction transistor (BJT) controlling power transfer through the coil unit, and a current sensing resistor sensing a current flowing through the BJT so as to produce a sensed voltage thereacross. A switching controller includes a current source supplying a first current, a current generating module generating, based on an input voltage associated with the sensed voltage, a second current, which is proportional to the current flowing through the BJT, a multiplexing module selecting one of the first and second currents as an output current, and a driving module outputting, based on the output current, a driving current, which is proportional to the output current, to the BJT to thereby conduct the BJT.

Switching power converting apparatus, switching controller for the same, and method of controlling a bipolar junction transistor of the same

The present invention discloses a power factor correction circuit, a control circuit therefor and a method for driving a power factor correction circuit. The power factor correction circuit receives rectified power obtained by rectifying AC power, and corrects the power factor thereof. The power factor correction circuit includes an inductor, and it generates a reference signal as a limit for the inductor current. The reference signal is proportional to Comp/Vin, wherein Comp is a signal relating to a feedback signal, and Vin is a voltage signal relating to the AC power or the rectified power.

Power factor correction circuit, control circuit therefor and method for driving load circuit through power factor correction

A high voltage half-bridge driver circuit has a high voltage terminal and a floating node to be connected with a high side switch therebetween. When turning on the high side switch, a high voltage offset detection circuit detects a voltage related to the voltage at the floating node for triggering a zero voltage switching signal.

High voltage offset detection circuit

A high voltage H-bridge driver circuit has a high voltage terminal and a floating node to be connected with a high side switch therebetween. When turning on the high side switch, a high voltage offset detection circuit detects a voltage related to the voltage at the floating node for triggering a zero voltage switching signal.

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Xikou, China

Jyun-Che Ho