Richtek Technology Corporation

Chun-Tsung Chen

Kwan-Jen Chu

Nien-Hui Kung

Li-Wei Lee

Liang-Pin Tai

Chung-Lung Pai

Jwin-Yen Guo

Chien-Ping Lu

Tzu-Huan Chiu

Chun-Hsiung Chang

Shih-Hui Chen

Ying-Hsin Hsing

Chin-Chiang Yeh

Tsan-Huei Wu

Po-Shun Chung

Chung-Fu Wang

A power safety system includes a first MOS, a second MOS, a switch and a body controller. The first MOS is connected between a power input and a power output. The second MOSFET is connected between the power output and a charging output. The switch has an end connected to the body of the first MOS, and the opposite end switched between the source and the drain of the first MOS. A body controller controls the switch according to the voltage at the power input and the voltage at the power output, to connect the body of the first MOS to the source or the drain of the first MOS. By switching the switch, the first MOS will have a parasitic diode effective to prevent a reverse current from the power output to the power input.

Power safety system

A LED driving topology includes a LED array and a current source connected in series between two power inputs receiving a positive voltage and a negative voltage respectively. This topology increases the voltage difference across the LED array and hence has the capability of lighting up more serially connected LEDs, without requiring an additional boost circuit or a high voltage. In addition, the circuit of the current source can be made by a low-voltage manufacturing process.

LED driving topology, light source module based thereon, and digital camera having the same

The present invention discloses an overvoltage protection (OVP) circuit for use in a charger circuit system, comprising: a power transistor electrically connected between a voltage supply and a battery; an OVP circuit which turns off the transistor when a voltage supply exceeds a threshold value; and a multiplexing circuit electrically connected between an output of the OVP circuit and the gate of the transistor. The present invention also discloses a charger circuit with an OVP function, comprising: a single power transistor electrically connected between a voltage supply and a battery; an OVP control circuit which turns off the power transistor when a voltage supply exceeds a threshold value; and a charger control circuit which controls the gate of the power transistor to determine a charge current to the battery when the voltage supply does not reach the threshold value.

Overvoltage protection circuit for use in charger circuit system and charge circuit with overvoltage protection function

The present invention discloses a dual power switch and a voltage regulator using the dual power switch. The dual power switch comprises a PMOS power switch and an NMOS power switch connected in parallel and operating according to corresponding predetermined conditions, respectively.

Dual power switch with activation control and voltage regulator using same

A class-D audio amplifier is protected by thermal regulation which decreases the gain of the class-D audio amplifier by asserting an over-temperature signal when the temperature of the class-D audio amplifier is detected to be higher than a threshold. The output of the class-D audio amplifier is therefore reduced by the smaller gain, and the chance for the class-D audio amplifier to stop working due to overheating is greatly reduced.

Thermal regulation of a class-D audio amplifier

A direct current voltage boosting/bucking device includes a direct current voltage boosting circuit and a low drop-out (LDO) linear voltage converting circuit. The direct current voltage boosting circuit boosts an input voltage so as to generate an output voltage higher than the input voltage. The LDO linear voltage converting circuit converts the output voltage into a load voltage that is to be provided to a load, and controls the direct current voltage boosting circuit in accordance with a feedback signal from the load such that the output voltage and the load voltage have a minimum drop-out voltage differential therebetween and such that current flow through the load is maintained at a determined level.

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Taipei, Taiwan

Chun-Tsung Chen