Patent ID: 7250742
Filing Date: 2007-07-31
Classification: G05F,H02M

Abstract:
1. A circuit for providing power factor correction comprising: a bridgeless boost converter circuit; an input circuit for an AC line voltage; a control circuit receiving the AC line voltage, the control circuit being operative to provide a pulse width modulated signal to control the on time of a PFC switch of the bridgeless boost converter circuit; the control circuit comprising: a scaling device operable to scale down an AC line voltage from bipolar to uni-polar form; an analog to digital converter operable to convert the uni-polar AC voltage into digital data; a digital rectifier operable to process the digital data of the uni-polar AC voltage to provide a half-sinusoidal AC signal that is proportional to and in phase with the input AC line voltage; and a pulse width modulation circuit responsive to the half sinusoidal AC signal to control an on time of a PFC switch of the bridgeless boost converted circuit.