POWER FACTOR COMPENSATION CIRCUIT FOR BOOST TYPE CONVERTER

摘要

The disclosed power factor correction circuit compensates for the variation of the output DC voltage to reduce current distortion and obtain high power factor, and the configuration of the circuit is simplified by maintaining the in-phase and increasing the level of the input current according to the input AC voltage without configuring the feedforward. Let's do it.;According to the present invention, a boost converter accumulates energy in a coil according to an on and off state of a switching transistor and superimposes an input DC voltage on the energy stored in the coil, and outputs a voltage signal corresponding to a current flowing when the switching transistor is turned on. The current sensing unit is generated, and the comparator voltage signal for compensating the variation of the output DC voltage and the comparison reference voltage signal whose level is varied according to the variation of the output DC voltage output by the boost converter is generated. The first signal synthesizing unit synthesizes the generated comparison reference voltage signal and the voltage signal sensed by the current sensing unit to generate a comparison signal, and the second signal synthesizing unit synthesizes the compensation voltage signal and the reverse sawtooth signal generated by the output sensing unit to output the direct current. Generates an inverted sawtooth signal in which voltage fluctuations are compensated for, and a comparison signal and a second signal of the first signal synthesis unit The comparator compares the compensated reverse sawtooth signal of the synthesizer to generate an off control signal of the switching transistor, and the driving unit turns on the switching transistor according to a clock signal synchronized with the rising edge of the reverse sawtooth signal and according to the off control signal of the comparator Turn off the switching transistor.