PFC CIRCUIT, LOAD DRIVE CIRCUIT AND SIGNAL CONTROL METHOD

摘要

A PFC circuit, a load drive circuit and a signal control method. An input end of a PFC circuit (500) receives a chopping voltage; the PFC circuit (500) comprises a main switching tube (S1), a Ton control unit (510), and a detection and compensation unit (520). Within the range of a maximum value, a control signal of the Ton control unit is positively correlated to a chopping angle of the chopping voltage. The detection and compensation unit is used for detecting the chopping angle of the chopping voltage and generating a compensation signal with an amplitude value positively correlated to the chopping angle. A comparison signal of the Ton control unit is controlled according to the compensation signal, so that within the range of the maximum value, the control signal corresponding to an equal chopping angle rises, thereby reducing ineffective regulating process during the dimming process.