Patent ID: 6178104
Filing Date: 2001-01-23
Classification: H02M,Y02B,Y02P

Abstract:
A Power Factor Correction circuit using a reverse sawtooth waveform, comprising:a converter which includes an inductor coupled to an input voltage, a switch controlling a current flowing through the inductor, and a rectifier for rectifying an output voltage of the inductor and supplying the rectified voltage to a load;a current detector coupled to the switch for detecting the current flowing through the inductor when the switch is turned on;an error amplification unit which includes a divider for dividing the output voltage of the converter, and an error amplifier for amplifying a difference voltage between the divider output voltage and a reference voltage;a comparative wave generator which includes an oscillator generating a reverse sawtooth waveform having a sawtooth period and a decreasing wave segment in each sawtooth period, the generator further including a reference clock signal having a clock period equal to the sawtooth period and a multiplier multiplying an output voltage of the error amplifier and the reverse sawtooth waveform by a predetermined gain; anda switching driving means for turning off the switch when an output voltage of the current detector is equal to an output voltage of the multiplier of the comparative wave generator, and turning on the switch when a state of the reference clock signal is changed.