Patent ID: 9240711
Filing Date: 2016-01-19
CPC Classification: H02M,H05B,Y02B

Claim Text:
1. A power factor correction circuit applicable in a constant-current control circuit, wherein the constant-current control circuit comprises a current control circuit and a driving control circuit, an output of the current control circuit is connected to the driving control circuit, an output of the driving control circuit is connected to a control terminal of a switching tube, the power factor correction circuit comprises a valley-fill PFC power factor correction circuit and a harmonic compensating circuit, an input signal of the harmonic compensating circuit is a driving signal output by the driving control circuit or is a switching tube current sample signal of the switching tube, and an output signal of the harmonic compensating circuit is output to the current control circuit, and the output signal of the harmonic compensating circuit is a periodic signal with a period same as that of an input current of the power factor correction circuit, each period comprises a first time duration in which the output signal is a level signal and a second time duration in which the output signal increases from the level signal and then decreases until returning to the level signal or the output signal decreases from the level signal and then increase until returning to the level signal, wherein the first time duration is a time duration in which the input current is 0, and the second time duration is a time duration in which the input current is not 0.