Richtek Technology Corporation

Yu-Wen Chang

Isaac Y Chen

Leng-Nien Hsiu

Ta-Yung Yang

Chien-Yang Chen

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

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 switching regulator includes a power stage circuit, an auxiliary winding, a start-up switch, and a power switch controller circuit. The power switch controller circuit includes a multifunction pin, a start-up controller circuit, and a feedback compensation circuit. The multifunction pin is coupled to a control terminal of the start-up switch, to deliver different signals with different functions under at least two different modes, respectively. The start-up controller circuit generates a start-up signal in a start-up mode, wherein the start-up signal is delivered to a control terminal of the start-up switch through the multifunction pin. An output terminal of the feedback compensation circuit is coupled to the multifunction pin, to provide a compensation signal at the multifunction pin in an operation mode.

Switching regulator and power switch controller circuit thereof

The present invention discloses a switching regulator capable of reducing current ripple and a control circuit thereof. The switching regulator includes a buck power stage circuit and a control circuit. The control circuit includes an operation signal generation circuit and a current source circuit for reducing current ripple. The current source circuit is coupled to the operation signal generation circuit and the buck power stage circuit, for operating a ripple reduction switch therein according to an operation signal, to convert the output voltage to a load voltage between a load node and a reference node, and to reduce a current ripple of the output current, so as to generate a load current which is supplied to a load circuit, wherein the load circuit is coupled between the load node and the reference node, and the current source circuit is coupled between the output node and the load node.

Growing community of inventors

Nantou, Taiwan

Yu-Wen Chang