Power factor correction (PFC) circuit, load driving circuit and signal control method

Abstract

The invention discloses a power factor correction (PFC) circuit, a load driving circuit and a signal control method. An input end of the PFC circuit receives chopped wave voltage. The PFC circuit comprises a main switch tube and a Ton control unit. Control signals of the Ton control unit is in positive correlation with chopped wave angles of the chopped wave voltage within a range smaller than or equal to a maximum. The PFC circuit further comprises a detection compensation unit, and the detection compensation unit is used for detecting the chopped wave angles of the chopped wave voltage, generating compensating signals with amplitude in positive correlation with the chopped wave angles and controlling comparison signals of the Ton control unit according to the compensating signals so as to enable control signals corresponding to the equal chopped wave angles within a range of the control signals smaller than or equal to the maximum. The PFC circuit, the load driving circuit and the signal control method can shorten invalid adjusting process in a light-dimming process.

Description

technical field [0001] The invention relates to the field of circuits, in particular to a PFC circuit, a load driving circuit and a signal control method. Background technique [0002] In the field of lighting, it is necessary to adjust the brightness or color of the light source in many occasions, which requires the lighting system to have an adjustment function. Currently, the chopper dimming technology is more commonly used, such as figure 1 As shown, the dotted line part is an implementation structure of the existing chopper dimmer. After the grid voltage Vac is acted on by the chopper dimmer, the voltage on the light source load RL is as follows: figure 2 For the chopping voltage shown, the phase angle α corresponding to the triggering conduction time of the transistor TRIAC in the chopping dimmer is the chopping angle of the chopping voltage. The internal resistor R11 of the chopper dimmer is a variable resistor. Adjusting the resistance value of the variable resist...

AI Technical Summary

Problems solved by technology

While the chopper dimmer adjusts the chopping angle α of the chopping voltage from zero to the critical value αx, the output current Io of the PFC circuit remains unchanged, which is meaningless for dimming, and for users, The adjustment process at this stage is an invalid adjustment process

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