Chengdu Monolithic Power Systems Co., Ltd.

Hangzhou Mps Semiconductor Technology Ltd.

Hongqiang Qin

Eric X Yang

Qiming Zhao

Bairen Liu

Licheng Sheng

Bo Yu

Naixing Kuang

Paul T Ueunten

Yishan Ma

Song Qu

A BLDC motor system having a power stage, a hall sensor and a logical control circuit is discussed. The BLDC motor system improves performances by judging an initial rotation direction through the back electromotive force generated by the stator together with the induced signal sensed by the hall sensor.

BLDC motor system with reduced power loss and the initial rotation direction judging method thereof

A method of capacitive mode detection is used in a resonant converter. The resonant converter has a square wave generator having a first switch and a second switch, a resonant network, an isolated transformer having a primary winding and a second winding, and a rectifier network providing an output DC voltage for a load. The method of capacitive mode detection includes: detecting a voltage of the secondary winding and generating a voltage detection signal; detecting an output DC voltage of the rectifier network and generating a voltage detecting threshold; comparing the voltage detection signal with the voltage detection threshold when either of the first and the second switches is turned OFF; generating a flag signal indicating whether the resonant converter enters into a capacitive mode based on the comparison result.

Resonant converter with capacitive mode detection and associated detection method

A light-emitting element driver system has a power conversion circuit, a second switch and a control circuit, the power conversion circuit has a primary circuit, a transformer, a first rectified circuit and a second rectified circuit, the second rectified circuit provides a first signal, the second switch has a first terminal coupled to an output terminal of the first rectified circuit and a second terminal to provide a second signal, when a dimming signal is in a first state, the control circuit provides a first control signal to control the power conversion circuit based on the first signal, and meanwhile provides a second control signal to control the second switch based on the second signal.

Single stage LED driver system, control circuit and associated control method

A method having a negative output voltage at a negative output terminal of a charge pump tracking a positive output voltage at a positive output terminal of the charge pump. The charge pump comprises a plurality of switches and each of the plurality of switches has a serially coupled resistance. The method comprises selecting the serially coupled resistance for at least one of the plurality of switches to be different to each of the other respective serially coupled resistances associated to the other switches.

Charge pump and method of having negative output voltage tracking positive output voltage thereof

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Hangzhou, China

Hongqiang Qin