PFC CIRCUIT, LOAD DRIVE CIRCUIT AND CURRENT CONTROL METHOD

摘要

A Power Factor Correction (PFC) circuit (71), a load drive circuit, and a current control method. An input end of the PFC circuit receives a chopping voltage; an output current of the PFC circuit is inversely correlated to a chopping angle of the chopping voltage. The PFC circuit comprises a main switching tube and a ton generating unit (710), and further comprises a detection and compensation unit (720) used for detecting the chopping angle of the chopping voltage and generating a compensation signal correlated to the chopping angle according to the chopping angle. The compensation signal is utilized to control a comparison signal or reference signal of the ton generating unit (710), so as to control the turn-on time of the main switching tube to be inversely correlated to the chopping angle, and control the decreasing rate of the output current of the PFC circuit to be positively correlated to the chopping angle. Such a PFC circuit and current control method can reduce the minimum luminance of the light source load.