Richtek Technology Corporation

Richtek Technolpgy Corporation

Ta-Yung Yang

Jing-Meng Liu

Isaac Y Chen

Kuo-Chi Liu

Wei-Hsu Chang

Chih-Wen Hsiung

Tzu-Chen Lin

Yu-Chang Chen

Kun-Yu Lin

Hsin-Yi Wu

Chao-Chi Chen

Wu-Te Weng

Ying-Chieh Su

Chien-Yu Chen

Chien-Wei Chiu

Ting-Wei Liao

Kun-Huang Yu

Chung-Lung Pai

Kuo-Chin Chiu

Yi-Min Shiu

Yong-Zhong Hu

Shih-Ho Hsu

Yu-chang Chen

Chun-Lung Chang

Mao-Hui Kuo

Shih-Jen Yang

Chih-Hao Yang

Li-Wen Fang

Ping-Ching Huang

I-Chi Lin

Chang-Yi Lin

Wei-Chuan Wu

Chia-Hsien Yang

Fu-Ciao Syu

Shin-Li Lin

He-Yi Shu

Yu-Chieh Hsieh

Chih-Ching Lee

Syuan-Zong Lan

Yi-Ju Lu

A method for predicting failure of a cooling fan includes driving a motor of the cooling fan based on a control speed, generating a first speed according to an average speed of the motor, generating a first current according to an average current of the motor, retrieving a system coefficient from a memory, generating a current threshold according to the first speed and the system coefficient, and triggering an alarm signal if the first current exceeds the current threshold by a threshold amount.

Method and system for failure predication of cooling fan

A power factor correction control circuit for correcting a power factor of a rectified power to generate an output power supplied to a load, includes: a reference voltage generator circuit generating a reference voltage according to a rectified voltage of the rectified power; and a feedback modulation circuit generating a modulation control signal based upon the reference voltage and a feedback signal related to an output voltage of the output power, to control at least one switch of a power stage circuit to switch an inductor in the power stage circuit and to thereby regulate the output voltage. The reference voltage generator circuit selects one of at least two candidate voltages as the reference voltage according to a comparison result between the rectified voltage and at least one threshold, such that the output voltage is at least partially positively correlated with the rectified voltage.

Power supply system and power factor correction control circuit and control method thereof

The present invention provides a resonant switched capacitor voltage converter (RSCC), which is coupled to and operates synchronously with another RSCC. The RSCC includes: plural switches, a resonant inductor, a resonant capacitor, and a control circuit. The control circuit controls the switches, so that the resonant capacitor and the resonant inductor are connected in series to each other, to perform resonant operation in a switching period, thus converting an input voltage to an output voltage. The control circuit generates a zero current signal and a first synchronization signal when a resonant inductor current flowing through the resonant inductor is zero. The control circuit turns off at least one corresponding switch according to the zero current signal. The control circuit turns on at least one corresponding switch according to the zero-current signal and a second synchronization signal, so that the RSCC operates in synchronization with at least another RSCC.

Resonant switched capacitor voltage converter and control method thereof

A voltage regulator for converting an input voltage to an output voltage includes: a first and a second high-side switch, a first and a second low-side switch and a control terminal which is for generating a reference voltage or determining a forced pass-through mode. The output voltage is determined according to the reference voltage during a buck mode and a boost mode. When the input voltage is higher than a first threshold, the voltage regulator is operated in the buck mode. When the input voltage is lower than a second threshold, the voltage regulator is operated in the boost mode. When the input voltage is lower than the first threshold and is higher than the second threshold, the voltage regulator is operated in a pass-through mode. When a voltage of the control terminal is lower than a third threshold, the voltage regulator is operated in the forced pass-through mode.

Voltage regulator for use in flyback converter

A flyback power converter includes a power transformer, a first lossless voltage conversion circuit, a first low-dropout linear regulator and a secondary side power supply circuit. The first low-dropout linear regulator (LDO) generates a first operation voltage as power supply for being supplied to a sub-operation circuit. The secondary side power supply circuit includes a second lossless voltage conversion circuit and a second LDO. The second LDO generates a second operation voltage. The first operation voltage and the second operation voltage are shunted to a common node. When a first lossless conversion voltage is greater than a first threshold voltage, the second LDO is enabled to generate the second operation voltage to replace the first operation voltage as power supply supplied to the sub-operation circuit; wherein the second lossless conversion voltage is lower than the first lossless switching voltage.

Flyback power converter and secondary side power supply circuit and control method thereof

A multilevel buck converter includes a plurality of switches, an inductor, a flying capacitor, and a control circuit. The plurality of switches are coupled between an input terminal and a ground. The input terminal has an input voltage. The inductor is coupled between the plurality of switches and an output terminal for generating an inductor-current signal. The flying capacitor is coupled to the plurality of switches for generating a flying capacitor voltage. The control circuit is coupled to the output terminal and the plurality of switches for generating a plurality of switching signals according a feedback voltage and the inductor-current signal. The control circuit operates in a valley current mode with dual slope compensation.

Multilevel buck converter with valley current mode control and dual slope compensation

A power converter includes first to fourth switches, a flying capacitor, an inductor, an output capacitor and a control circuit. The first to fourth switches are sequentially coupled in cascode. The first switch is used to receive an input voltage. The flying capacitor is coupled across the second switch and the third switch, the inductor is coupled to the second switch, the third switch and the output capacitor. The output capacitor is used to output an output voltage. When the input voltage is less than an input voltage threshold, the control circuit is used to switch the first to fourth switches according to a resonant frequency. When the input voltage exceeds the input voltage threshold, the control circuit switch is used to the first to fourth switches according to a regulated frequency exceeding the resonant frequency.

Feedforward frequency response for resonant charge pump

An NMOS half-bridge power device includes: a semiconductor layer, a plurality of insulation regions, a first N-type high voltage well and a second N-type high voltage well, which are formed by one same ion implantation process, a first P-type high voltage well and a second P-type high voltage well, which are formed by one same ion implantation process, a first drift oxide region and a second drift oxide region, which are formed by one same etch process including etching a drift oxide layer; a first gate and a second gate, which are formed by one same etch process including etching a poly silicon layer, a first P-type body region and a second P-type body region, which are formed by one same ion implantation process, a first N-type source and a first N-type drain, and a second N-type source and a second N-type drain.

NMOS half-bridge power device and manufacturing method thereof

A resonant flyback power converter includes: a first and a second transistors which form a half-bridge circuit for switching a transformer and a resonant capacitor to generate an output voltage; a current-sense device for sensing a switching current of the half-bridge circuit to generate a current-sense signal; and a switching control circuit generating a first and a second driving signals for controlling the first and the second transistors. The turn-on of the first driving signal controls the half-bridge circuit to generate a positive current to magnetize the transformer and charge the resonant capacitor. The turn-on of the second driving signal controls the half-bridge circuit to generate a negative current to discharge the resonant capacitor. The switching control circuit turns off the first transistor when the positive current exceeds a positive-over-current threshold, and/or, turns off the second transistor when the negative current exceeds a negative-over-current threshold.

Resonant flyback power converter and switching control circuit and method thereof

A power supply system includes a power factor correction converter circuit and an isolated power converter circuit, wherein the power factor correction converter circuit corrects the power factor of a rectified power to generate a first output power, and the isolated power converter circuit converts the first output power to generate a second output power. The isolated power converter circuit includes a transformer, and the transformer includes a primary winding, a secondary winding, and an auxiliary winding. The auxiliary winding generates an auxiliary voltage which is related to the second output power. When the auxiliary voltage is lower than a disabled threshold, indicating that the voltage of the second output power is lower than a threshold, the power factor correction converter circuit provides a bypassing connection from the rectified power to the first output power and stops correcting the power factor of the rectified power.

Power supply system

A power converter includes first to fourth switches, a flying capacitor, an inductor, an output capacitor and a control circuit. The first to fourth switches are sequentially coupled in cascode. The first switch receives an input voltage, and the fourth switch is further coupled to a ground terminal. The flying capacitor is coupled across the second switch and the third switch, the inductor is coupled to the second switch, the third switch and the output capacitor. The output capacitor is used to output an output voltage. In a non-regulated mode, the control circuit switches the first to fourth switches according to a resonant frequency. In a regulated mode, the control circuit switches the first to fourth switches according to a regulated frequency exceeding the resonant frequency. When the flying capacitor is coupled to the inductor, the flying capacitor and the inductor can form a resonant circuit having the resonant frequency.

Power converter for reducing switching loss and enhancing system efficiency and control method thereof

A power conversion circuit includes an inductive switching power converter and a capacitive switching power converter. The inductive switching power converter switches an inductor to converter a DC power to a first power. The capacitive switching power converter switches a conversion capacitor to convert the first power to a charging power for charging a battery. The inductive switching power converter and the capacitive switching power converter flexibly operate in and dynamically switch between a regulation mode, a bypass mode or a combination thereof according to a parameter of the DC power.

High efficiency charging system and power conversion circuit thereof

An integration manufacturing method of a depletion high voltage NMOS device and a depletion low voltage NMOS device includes: providing a substrate; forming a semiconductor layer on the substrate; forming insulation regions on the semiconductor layer; forming an N-type well in the depletion high voltage NMOS device region; forming a high voltage P-type well in the semiconductor layer, wherein the N-type well and the high voltage P-type well are in contact with each other in a channel direction; forming an oxide layer on the semiconductor layer after the N-type well and the high voltage P-type well formed; forming a low voltage P-type well; and forming an N-type high voltage channel region and an N-type low voltage channel region, such that each of the depletion high voltage NMOS device and the depletion low voltage NMOS device is turned ON when a gate-source voltage thereof is zero voltage.

Integration manufacturing method of depletion high voltage NMOS device and depletion low voltage NMOS device

A conversion control circuit controls plural stackable sub-converters which are coupled in parallel to generate an output power to a load, the conversion control circuit includes: a current sharing terminal, wherein a current sharing signal is configured to be connected to the current sharing terminals, in parallel, of the plurality of the conversion control circuits; and a current sharing circuit, configured to generate or receive the current sharing signal which is generated according to an output current of the output power; wherein the conversion control circuit adjusts the power stage circuit according to the current sharing signal for current sharing among the plural stackable sub-converters.

Control circuit and method for use in stackable multiphase power converter

A high voltage device includes: a semiconductor layer, a well, a bulk region, a gate, a source, and a drain. The bulk region is formed in the semiconductor layer and contacts the well region along a channel direction. A portion of the bulk region is vertically below and in contact with the gate, to provide an inversion region of the high voltage device when the high voltage device is in conductive operation. A portion of the well lies between the bulk region and the drain, to separate the bulk region from the drain. A first concentration peak region of an impurities doping profile of the bulk region is vertically below and in contact with the source. A concentration of a second conductivity type impurities of the first concentration peak region is higher than that of other regions in the bulk region.

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Taoyuan, Taiwan

Ta-Yung Yang