Richtek Technology Corporation

Richtek Technology Corporation, R.o.c

Richtek Technology Corpoation

Ching-Hsiang Yang

Cheng-Hsuan Fan

Chao-Hsuan Chuang

Hung-Che Chou

Chih-Ping Tan

Jwin-Yen Guo

Shui-Mu Lin

A speaker driver circuit driven by positive and negative voltages, comprising: at least one operational amplifier providing an output to a headphone speaker, and a voltage converter receiving a supplied voltage (VDD), generating r-fold positive and negative voltages (r&#xb7;VDD and &#x2212;r&#xb7;VDD, wherein r is any positive real number except 1) according to the supplied voltage, and supplying the positive and negative voltages to the operational amplifier for its high and low operation voltage levels respectively.

Speaker driver circuit driven by positive and negative voltages

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 present invention discloses a multi-voltage headphone driver circuit comprising: at least one operational amplifier having an output supplied to a headphone speaker, the operational amplifier receiving a first power supply as its high operation voltage; a charge pump receiving a second power supply to generate a negative voltage corresponding to the second power supply in magnitude; and an m-fold circuit multiplying the negative voltage by m and providing the result to the operational amplifier as a low operation voltage thereof, wherein m is a real number.

Multi-voltage headphone drive circuit

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

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 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.

Growing community of inventors

Taoyuan, Taiwan

Ching-Hsiang Yang