Richtek Technology Corporation

Other

Richtek Technology Corporation, R.o.c

Richtex Technology Corp.

Chao-Hsuan Chuang

Cheng-Hsuan Fan

Hung-Che Chou

Ching-Hsiang Yang

Jing-Meng Liu

Chih-Ping Tan

Shui-Mu Lin

Kent Hwang

Nien-Hui Kung

Jien-Sheng Chen

Der-Jiunn Wang

Wei-Hsin Wei

Wen-Hung Huang

Yiu-I Lin

Tsung-Wei Huang

Kwan-Jen Chu

Liang-Pin Tai

Peng-Ju Lan

Cheng-Yuan Chang

Hsien-Ming Chiu

Shin-Lung Ho

A flyback voltage converter includes a transformer having a primary winding and a secondary winding, a switch serially connected to the primary winding for being switched to produce a current in the secondary winding, and a negative lock loop to adjust the peak value of the current in the secondary winding according to a current conduction time during which the current in the secondary winding is higher than a current threshold, such that the peak value of the current in the secondary winding will be in inverse proportion to the time.

Negative lock loop and control method for a flyback voltage converter

The phase node voltage or the PWM signal in an asynchronous boost converter is monitored to detect a phase node voltage ringing. When a phase node voltage ringing is detected, a detection signal is asserted to establish a bypass path to bypass the inductor of the converter. A charge bypass circuit is shunt to the inductor, and controlled by the detection signal to establish the bypass path. Due to the bypass path, the phase node voltage is maintained at a constant, and the phase node voltage radiation and input/output noise are eliminated.

Anti-ring asynchronous boost converter and anti-ring method for an asynchronous boost converter

The present invention discloses a half-voltage headphone driver circuit, comprising: at least one operational amplifier providing an output to a headphone speaker, and a charge pump receiving a supply voltage (VDD), generating a positive half-voltage and a negative half-voltage (VDD/2 and &#x2212;VDD/2) based on the supply voltage, and supplying the positive half-voltage and negative half-voltage as high and low operation levels to the at least one operational amplifier.

Half-voltage headphone driver circuit

For protecting a power system, two or three of over current, thermal and under voltage protection circuits are integrated as one protection circuit but operate independently, and one or more protection points thereof are adjusted dynamically in response to detected condition of the power system. Specifically, using voltage and current conditions in the power system to modify the over current protection and the thermal protection maximizes the performance of the power system and covers the process bias in the circuits.

Arrangement and method for an integrated protection for a power system

A class AB output stage includes a driver to generate a first drive signal and a second drive signal, and two bias voltage sources to provide two bias voltages to level shift the first and second drive signals, in order to drive a pair of high side and low side transistors, respectively. A control circuit provides a control signal to adjust the first and second bias voltages, so as to shift the bias point of the class AB output stage. The control signal is determined according to the currents in the high side and low side transistors and a programmable parameter. By adjusting the parameter, the bias point deviation can be removed to obtain both low quiescent current and best THD performance.

Class AB output stage with programmable bias point control

The present invention discloses a load-dependent frequency jittering circuit, comprising: a load condition detection circuit for receiving a switching signal and generating an output according to a load condition; a number generator for receiving the output of the load condition detection circuit and generating a number; a digital to analog converter for converting the output of the number generator to an analog signal; and an oscillator for generating a jittered frequency according to the output of the digital to analog converter.

Load-dependent frequency jittering circuit and load-dependent frequency jittering method

A linear voltage regulator comprises a transistor for converting a supply voltage to an output voltage. By directly monitoring the supply voltage and thereby rapidly responding when the supply voltage suffers a ripple, the linear voltage regulator enhances the stability of the output voltage.

High PSRR linear voltage regulator and control method thereof

Time-sharing technique is used for power conversion to improve the thermal dissipation thereof. In a power supply arrangement to provide a supply voltage to a load, a plurality of linear regulators are so switched that each time only one of them is enabled to convert an input voltage to the supply voltage, thereby each of them suffering less thermal dissipation.

Thermal dissipation improved power supply arrangement and control method thereof

A flyback converter has a controller to switch a power switch so as to convert an input voltage to an output voltage for a load by monitoring an output voltage dependent signal and a current sensing signal derived from a current flowing through the power switch, a light-load efficiency improving apparatus monitors the load and a supply voltage provided for the controller to selectively clamp the output voltage dependent signal when the load is lower than a first threshold value and the supply voltage is lower than a second threshold value, so as to increase the supply voltage.

Light-load efficiency improving method and apparatus for a flyback converter

A frequency jittering control circuit wherein by means of the characteristics of a PLL whose input switches between different frequencies, the output frequency of the PLL swings between the different frequencies to achieve the desired frequency jittering.

Frequency jittering control circuit and method for using the same

A control device, which controls a power-converting module that is coupled to a light-emitting component, includes a duration detecting unit and a control signal generator. The duration detecting unit compares the duration of a predetermined logic state of a pulsating input dim control signal with a reference time period. The control signal generator is enabled by the duration detecting unit so as to generate a control signal that enables the power-converting module to generate a drive voltage for driving the light-emitting component when the duration of the predetermined logic state is not longer than the reference time period. The duration detecting unit disables the control signal generator to disable the power-converting module when the duration of the predetermined logic state is longer than the reference time period.

Control method and device for a power-converting module that drives a light-emitting component

The present invention discloses a charge pump start up circuit comprising: a start up transistor having one end which is electrically connected with a voltage supply source, and another end which is electrically connected to a voltage node; and a charge pump circuit having an input which is electrically connected with the voltage node, and an output which is electrically with the gate of the start up transistor.

Charge pump start up circuit and method thereof

In a gamma voltage generator and gamma voltage generating method that can tune the gamma voltages individually, several gamma currents of a same magnitude are generated for each to flow through a variable resistive element to generate a variable common voltage and several variable voltages, from which a common gamma voltage and several first gamma voltages are generated. By use of the symmetric property of the gamma curve corresponding to those gamma voltages to be generated, several voltages are generated by mapping the first gamma voltages with the common gamma voltage as the center axis, and from which several second gamma voltages are derived. The common gamma voltage and the first and second gamma voltages are provided for those gamma voltages corresponding to the gamma curve.

Growing community of inventors

Jhubei, Taiwan

Chao-Hsuan Chuang