Richtek Technology Corporation

Grenergy Opto Inc.

Richtek Technology Corporation, R.o.c

Pei-Yuan Chen

Leng-Nien Hsiu

Yen-Ping Wang

Ko-Ming Lin

Jing-Meng Liu

Chia-Chieh Hung

Chia-Wei Liao

Wei-Chuan Su

Jian-Shen Li

Roland Van Roy

Chien-Yang Chen

Yen-Hui Wang

Chang-Yu Wu

Yu-Min Chen

Chun-Shih Huang

Chi-Hsiu Lin

Gang Zheng

Chih-Tai Cheng

The present invention provides a flyback power converter, a secondary side control circuit, and a control method thereof. The flyback power converter converts an input voltage to an output voltage, and provides a load current to a load circuit. The flyback power converter includes: a transformer circuit, a power switch circuit, a switch current sense circuit, a primary side control circuit, and a secondary side control circuit. The secondary side control circuit adaptively adjusts a frequency of a zero of a compensator gain function and/or a mid-frequency gain of the compensator gain function according to the load current, such that a number of poles of a system open loop gain function of the flyback power converter is at most more than a number of zeroes of the system open loop gain function by one under a crossover frequency.

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

The present invention provides a light emitting device driver circuit and a control circuit and a control method thereof. The light emitting device driver circuit includes a power stage circuit, a feedback circuit, and a control circuit. The control circuit includes a comparison circuit, a hysteresis control circuit, and a bleeder circuit. The control circuit generates an analog control signal according to a rectified dimmer signal and an output signal, for controlling the power stage circuit to regulate an output current, which is supplied to a light emitting device circuit to determine its brightness. When the analog control signal decreases to a predetermined hysteresis low level, the light emitting device driver circuit operates in a cut-off mode wherein the bleeder circuit consumes a bleeder current so as to maintain the output current at a zero current, for keeping the light emitting device circuit OFF.

Light emitting device driver circuit and control circuit and control method thereof

The present invention discloses a switching regulator compatible with an electronic transformer and a control method thereof. The switching regulator includes: a power stage circuit, a control circuit, and an input current peak & valley setting circuit. The control circuit is coupled to the power stage circuit, for generating an operation signal according to a feedback signal and a peak & valley setting signal, to operate at least one power switch in the power stage circuit, so as to convert a rectified input voltage to an output voltage. The input current peak & valley setting circuit is coupled to the control circuit, for generating the peak & valley setting signal such that in one cycle period, the input current has multiple valleys forming a semi-sinusoidal contour.

Switching regulator compatible with electronic transformer and control method thereof

A power converter circuit of a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit, for cooperating with a dimmer and an electric transformer. The control circuit configures the boost converter circuit to alternatively operate in a current conducting mode and an off mode, to draw current from the electric transformer in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the configuration of the dimmer so that the low power illumination device may perform the required dimming function.

Power converter circuit for low power illumination device, control circuit thereof and method thereof

A power converter circuit for a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit. The control circuit configures the boost converter circuit to alternately operate in a current conducting mode and an off mode, to draw different values of the current from an electric transformer in different periods in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the output of the boost converter circuit so that the low power illumination device may function normally.

The present invention discloses a light emitting device control circuit with dimming function and a control method thereof. The light emitting device control circuit includes: a dimmer circuit, a rectifier and filter circuit, a power converter circuit, and a headroom voltage regulation circuit. The dimmer circuit generates an AC dimming voltage according to an AC voltage. The rectifier and filter circuit generates an input voltage according to the AC dimming voltage. The power converter circuit operates according to a control signal to convert the input voltage to an output voltage which is supplied to a light emitting device circuit. The headroom voltage regulation circuit generates the control signal according to a reference value and a difference between the input voltage and the output voltage, and regulates the difference at a level corresponding to the reference value by a feedback control loop.

Light emitting device control circuit with dimming function and control method thereof

A power-factor-improving circuit and method for an offline converter block the DC component and obtain the AC component of an input voltage of the offline converter. The AC component is superpositioned onto a DC bias signal to generate a dimming signal for the offline converter to adjust an output current of the offline converter. The offline converter has a high power factor due to the dimming signal with the AC component of the input voltage. In addition, the average of the dimming signal is determined by the DC bias signal, hence the output current can be precisely controlled according to the DC bias signal.

Power-factor-improving circuit and method for an offline converter

The present invention discloses a switching regulator and a control circuit and a control method thereof. The switching regulator generates a compensation signal according to a feedback signal, and generates a driving signal according to the compensation signal, to control a power stage for converting an input voltage to an output voltage. The compensation signal is adjusted according to the input voltage, such that when the input voltage is equal to or lower than a predetermined level, the compensation signal is kept at a predetermined value.

Switching regulator and control circuit and control method thereof

The present invention discloses a control circuit and a control method of a light emitting device circuit. When the light emitting device circuit is normally connected in normal operation, an output current is regulated to a predetermined current. When the light emitting device circuit is removed, an output voltage is regulated to a predetermined voltage. When the light emitting device circuit is reconnected, the output current is regulated to the predetermined current. The output voltage is at or above a level when the light emitting device circuit is normally connected in normal operation, and the predetermined voltage is lower than this level.

Control circuit and control method of light emitting device circuit

The present invention discloses a light emitting device power supply circuit, a light emitting device control circuit and an identifiable light emitting device circuit therefor, and an identification method thereof. The light emitting device control circuit includes an operation signal generation circuit and an identification circuit. The operation signal generation circuit determines whether the light emitting device control circuit operates in an identified mode or amiss mode according to an enable signal. In the identified mode, the light emitting device control circuit operates a power stage circuit to supply an output current to an identifiable light emitting device circuit. In the miss mode, an output voltage is maintained at a predetermined level. The identification circuit determines whether the light emitting device control circuit switches from the miss mode to the identified mode according to whether the output voltage meets a condition.

Light emitting device power supply circuit, light emitting device control circuit and identifiable light emitting device circuit therefor and identification method thereof

The present invention discloses an active bleeder circuit capable of triggering a tri-electrode AC switch (TRIAC) circuit in all phase. The active bleeder circuit receives a rectified signal having an OFF phase and an ON phase. The active bleeder includes: a detection circuit for generating a detection signal according to the rectified signal and accumulating the detection signal in the OFF phase of the rectified signal; and a current sinker circuit coupled to the detection circuit, for generates a latching current to trigger the TRIAC circuit by operating a switch when the detection signal exceeds a predetermined level. The present invention also discloses a light emitting device power supply circuit and a TRIAC control method using the active bleeder circuit.

Active bleeder circuit triggering TRIAC in all phase and light emitting device power supply circuit and TRIAC control method using the active bleeder circuit

A control circuit of a switching regulator, which controls rectified power within a predetermined range, detects an input voltage and an input current to generate a voltage detection signal and a current detection signal respectively, and the voltage detection signal and the current detection signal are multiplied by one the other to generate a power index. The control circuit generates an error signal according to the power index and a reference signal. A low-pass-filter filters a high frequency band in the process. A control signal generation circuit of the control circuit generates a control signal according to the error signal. And a driver circuit of the control circuit generates an operation signal according to the control signal, for switching a power switch to convert the rectified power to an output voltage.

The present invention discloses a light emitting device power supply circuit, a light emitting device driver circuit and a control method thereof. The light emitting device driver circuit is coupled to a tri-electrode AC switch (TRIAC) dimmer circuit, and it controls the brightness of a light emitting device circuit according a rectified dimming signal. The light emitting device driver circuit includes a power stage circuit and a light emitting device control circuit. The light emitting device control circuit generates a switch control signal. The power stage circuit operates at least one power switch thereof according to the switch control signal to generate a latching current for firing the TRIAC dimmer circuit, and the latching current is inputted to the light emitting device circuit.

Light emitting device power supply circuit, and light emitting device driver circuit and control method thereof

A gas-discharge lamp controller utilizing a novel preheating phase control mechanism, having: a supply voltage tracking reference voltages generator, biased between a supply voltage and a reference ground, for generating a first reference voltage which is proportional to the supply voltage; and a control unit, for generating a high threshold signal according to the first reference voltage and a saw-tooth signal, the peak value of the saw-tooth signal being proportional to the supply voltage, wherein the control unit has a preheating phase, the high threshold signal is coupled with the first reference voltage during the preheating phase, and the time duration of the preheating phase is set by a predetermined number of periods of the saw-tooth signal.

Gas-discharge lamp controller utilizing a novel preheating phase control mechanism

The present invention discloses an electronic ballast with dimming control from power line sensing for a fluorescent lamp, comprising: a control voltage generator, used to generate a control voltage according to a switching count of a power line; an oscillator, used to generate an oscillating signal, wherein the oscillating signal is of a fixed frequency and has a rising voltage portion and a falling voltage portion; and a comparator, used to generate a high side gating signal according to voltage comparison of the oscillating signal and the control voltage.

Growing community of inventors

Taoyuan, Taiwan

Pei-Yuan Chen