Patent ID: 8089255

Claim:
A power factor correction power supply unit for correcting a power factor of a boost converter, comprising: a switching device; an input voltage detection circuit for detecting a magnitude of an input voltage and outputting an input voltage detection signal; an output voltage detection circuit for detecting a magnitude of an output voltage and outputting an output voltage detection signal; an error amplifier for outputting an error signal obtained by amplifying a difference between the output voltage detection signal and a reference voltage; an ON width generation circuit for generating an ON time width of the switching device determined by multiplying a difference between the error signal and a predetermined bias voltage by a predetermined coefficient; an OFF width generation circuit for generating an OFF time width of the switching device determined by dividing a product of the input voltage detection signal, the difference between the error signal and the predetermined bias voltage, and the predetermined coefficient, with a difference between the output voltage detection signal and the input voltage detection signal; and a switching device driving circuit for conducting an ON/OFF control over the switching device upon receiving a turn-on timing signal for turning on the switching device as soon as the OFF time width of the switching device generated by the OFF width generation circuit is terminated and upon receiving a turn-off timing signal for turning off the switching device as soon as the ON time width of the switching device generated by the ON width generation circuit is terminated.