Richtek Technology Corporation

Richtek Technology Corporation, R.o.c

Ricktek Technology Corporation

Richtek Technologies Corporation

Isaac Y Chen

Chien-Fu Tang

Yi-Wei Lee

Jiun-Hung Pan

An-Tung Chen

Jyun-Che Ho

Shao-Hung Lu

Tong-Cheng Jao

Jo-Yu Wang

Tzu-Chen Lin

Yung-Chih Lai

Hsin-Yi Wu

Ta-Yung Yang

Jing-Meng Liu

Yu-Chang Chen

Leng-Nien Hsiu

Yi-Min Shiu

Chien Fu Tang

Chi-Hua Lin

Tsung-Hsi Yang

Chien-Hung Chen

Liang-Pin Tai

Chien-Yang Chen

Pei-Kai Tseng

Li-Di Lo

Kuang-Feng Li

Yu-Wen Chang

Yueh-Ming Chen

Jung-Pei Cheng

Kuo-Chi Liu

Yu-Lin Yang

Kun-Yu Lin

Pei-Sheng Tsu

Kuang-Fu Chang

Fu-Sheng Tsai

Yen-Te Lee

Yu-Min Chen

Chung-Cheng Chang

Sao-Hung Lu

Kai-Chuan Chan

Yin-Chang Chen

Pei Kai Tseng

Wei-Haur Chan

Su-Yuan Lin

Pei-kai Tseng

Li-Yang Hsiao

Nai-Yuan Liang

A low delay time power converter circuit includes a driver circuit and a load. The driver circuit generates a switching driving signal to control the load. The driver circuit includes a switching control circuit and an output stage circuit which includes a first power switch, a second power switch and an impedance adjusting circuit. When the switching control circuit controls the switching driving signal to a first voltage level at a first time point, the first power switch is turned ON and then is turned OFF after a predetermined period. When the switching control circuit controls the switching driving signal to a second voltage level at a second time point, the second power switch is turned ON. The time point when the first power switch is turned OFF is earlier than the second time point. A resistance of the impedance adjusting circuit is larger than a conductive resistance of the first power switch.

Low delay time power converter circuit and driver circuit thereof

A dimmer interface circuit includes a buffer stage circuit and a PWM control circuit. The buffer stage circuit converts a dimming input signal to a dimming buffer signal. The buffer stage circuit includes: a power rail generation circuit, which generates a power rail according to the dimming input signal adaptively, so that the dimming input signal is between a high level voltage and a low level voltage of the power rail; and an amplification circuit, which receives the dimming input signal, to generate the dimming buffer signal. The power rail supplies electrical power to the amplification circuit, wherein the amplification circuit operates within a range between the high level voltage and the low level voltage. The PWM control circuit converts the dimming buffer signal to a PWM dimming signal, so as to adjust a brightness of an LED module.

Dimmer interface circuit and buffer stage circuit thereof

A current sensing circuit having self-calibration includes two leads, a sensing element having a sensing resistance, and a sensing and calibration circuit. The sensing and calibration circuit senses and calibrates a sensing voltage of the sensing element, and senses a sensing current through the sensing element according to the sensing resistance and the sensing voltage, to generate a current sensing output signal. The sensing and calibration circuit includes two pads, a V2I circuit, a current mirror circuit and an I2V circuit. The sensing element has a first temperature coefficient (TC). The TC and/or the resistance of an adjusting resistor in the V2I circuit and an adjusting resistor in the I2V circuit are determined according to the first TC, such that the TC of the current sensing output signal is equal to 0.

Current sensing circuit having self calibration

AN LED driving apparatus includes a power stage circuit and a dimming control circuit. The power stage circuit drives an LED circuit. The dimming control circuit includes a duty ratio conversion circuit, a digital-to analog conversion (DAC) circuit, an error amplifier (EA) circuit and a modulation control circuit. The duty ratio conversion circuit converts a PWM dimming signal to a digital duty ratio signal. The DAC circuit converts the digital duty ratio signal to an analog reference signal. The EA circuit generates an error amplified signal according to a difference between the analog reference signal and an output current related signal. The modulation control circuit generates a PWM control signal according to the error amplified signal, to control the power switch, such that the output current relates to a dimming duty ratio, whereby the dimming control circuit dims the LED circuit according to the PWM dimming signal.

Light emitting device driving apparatus and dimming control circuit and dimming control method thereof

An output stage circuit for transmitting data via a bus includes a high side switch, a high side diode structure, a high side clamp circuit, a low side switch, and a low side diode structure. An impedance circuit of the bus is coupled between the high side switch and the low side switch, for generating a differential output signal according to high and low side output signals. A high side N-type region of the high side diode structure encompasses a high side P-type region thereof, and a low side N-type region of the low side diode structure encompasses a low side P-type region thereof. The high side clamp circuit is connected to the high side N-type region in series, for clamping a voltage of the high side N-type region to be not lower than a predetermined voltage, to prevent a parasitic PNP bipolar junction transistor from being turned ON.

Output stage circuit for transmitting data via bus

A power supply apparatus having multiple output ports includes: a master power supply circuit for supplying a master output power via a master power switch; a slave power supply circuit for supplying a slave output power via a slave power switch; and a shared resistor coupled between a power management node and a reference ground level. The slave sensing circuit outputs the slave sensing current via a slave power management pin, to generate a total power signal at the power management node. The master control circuit senses the total power signal via the master power management pin, to determine an adjustment current. The slave control circuit controls the slave power switch according to a voltage at the slave power management pin, to adjust the slave output power, so that a total power of the master output power and the slave output power does not exceed a predetermined power range.

Power supply apparatus and master power supply circuit, slave power supply circuit and control method thereof

Whether a synchronous signal includes a synchronous pulse is determined by detecting whether there is a positive pulse higher than a positive threshold followed by a negative pulse lower than a negative threshold. The pulse signal detection method includes: comparing the synchronous signal with the positive threshold; comparing the synchronous signal with the negative threshold; and determining that the synchronous pulse exists when the positive pulse of the synchronous signal is higher than the positive threshold and the negative pulse of the synchronous signal is lower than the negative threshold in a post detection period after the positive pulse of the synchronous signal is determined higher than the positive threshold.

Power control circuit, pulse signal detection circuit, and pulse signal detection method

A memory circuit includes a memory unit, a memory control circuit and a pseudo ground voltage generation circuit. The memory control circuit includes: a level shifter circuit coupled to a variable supply voltage; a driver circuit coupled to the pseudo ground voltage generation circuit at the pseudo ground node. The driver circuit is powered by the variable supply voltage and generates an access signal according to the driving signal, to access data from the memory unit. Under a high-voltage operation, the variable supply voltage provides a first supply voltage level, so that a high level of the access signal corresponds to the first supply voltage level and the pseudo ground voltage generation circuit provides a pseudo ground voltage level at the pseudo ground node. A voltage difference between the first supply voltage level and the pseudo ground voltage level is smaller than a withstand voltage of the driver circuit.

Memory circuit having pseudo ground

A transmission interface with noise reduction function includes a first circuit and a second circuit, for transmitting a signal from the first circuit to the second circuit or from the second circuit to the first circuit. The first circuit includes a first sub-winding and a first wire unit, and the second circuit includes a second sub-winding and a second wire unit. When an electromagnetic noise passes through the first sub-winding and the first wire unit, two loop currents are respectively generated, and the currents have opposite directions to cancel each other so as to reduce the electromagnetic noise. Or, when an emitting current corresponding to the signal flows through the first sub-winding and the first wire unit, two magnetic fields are respectively generated, and the magnetic fields have opposite directions to cancel each other so as to reduce the electromagnetic interference.

Transmission interface having noise reduction function

A discrete-time current sense circuit includes: a current mirror circuit, which includes: a power switch, for providing the communication current; and a sampling switch, which is for sampling the communication protocol current in a sampling period in a discrete manner, to generate a sampling current; a bias circuit, for providing a reference voltage to the reference node in the sampling period according to a communication protocol voltage of the communication protocol voltage node; a signal conversion circuit, for generating the discrete-time current sense signal according to the sampling current; and a first switch, for operating to determine the sampling period; wherein the sampling period is part of a complete period in which the power switch provides the communication protocol current.

Communication protocol circuit and discrete-time current sense circuit and 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

The present invention discloses a short circuit and/or bad connection detection method for use in a power supply system. The power supply system includes a power converter which converts an input voltage to an output voltage and supplies an output current to an electronic device. In the short circuit detection method, the conversion from the input voltage to the output voltage is disabled in a disable time period, and whether a short circuit occurs is determined according to the decreasing speed of the output voltage. In the bad connection detection method, an actual voltage and an actual current received by the electronic device are compared with the output voltage and the output current, to determine whether a bad connection occurs.

Power supply system and short circuit and/or bad connection detection method thereof, and power converter thereof

A flyback power converter includes: a transformer, a power switch, a switch control unit, a synchronous rectifier switch and a secondary side control circuit. The secondary side control circuit includes: a switch signal generation circuit and a first power conversion circuit. The secondary side control circuit is coupled to the synchronous rectifier switch and the secondary winding of the transformer. The switch signal generation circuit generates the synchronous rectifier switch signal selectively according to a first power or a second power, to control the synchronous rectifier switch. The first power is related to the output voltage. The first power conversion circuit generates the second power according to a secondary phase signal on a phase node between the secondary winding of the transformer and the synchronous rectifier switch.

Flyback power converter and secondary side control circuit thereof

The present invention provides a power switch control circuit and an open detection method thereof. The power switch control circuit is for generating an operation signal at an operation signal output pin according to an input signal, wherein the operation signal is for operating a power switch. The power switch control circuit includes: a current injection circuit, which is connected to the operation signal output pin, and provides a predetermined current to the operation signal output pin according to an enable signal; and an open detection circuit, which is coupled to the current injection circuit, and determines whether a connection between the operation signal output pin and the power switch is open according to a level of the operation signal output pin at a detection time point or according to a level variation of the operation signal output pin during a detection time period, whereby an open detection signal is generated.

Power switch control circuit and open detection method thereof

A flyback power converter circuit converting an input voltage to an output voltage includes a transformer, a power switch, a synchronous rectifier (SR) switch, and a secondary side control circuit. The secondary side control circuit controls the SR switch to be ON when the power switch is OFF. The secondary side control circuit includes a driving switch for controlling the SR switch, a synchronous control circuit powered by a voltage related to the output voltage, which controls the driving switch to operate the SR switch, and a clamping circuit including a clamping switch and a clamping switch control circuit. The clamping switch control circuit controls the clamping switch according to a current inflow terminal voltage of the clamping switch and/or the voltage related to the output voltage, such that, during a secondary side power-on period, an equivalent impedance of the current inflow terminal of the clamping switch is smaller than a predetermined clamping impedance.

Flyback power converter circuit and secondary side controller circuit thereof

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Zhubei, Taiwan

Isaac Y Chen