Patent ID: 7279868

Claim:
A bi-directional boost circuit for power factor correction, comprising: a first diode, a second diode, a first inductor, a second inductor, a first switch, and a second switch to convert an AC input voltage, rectify the AC input voltage, and output an intermediate DC voltage; and a power factor control circuit, the power factor circuit including a waveform generator to receive the AC input voltage and generate a haversign waveform; a pulse width modulator to generate a pulsed signal based on the intermediate DC voltage; a multiplier to multiply the haversign waveform and the pulsed signal and to create a multiplied haversign signal; an integrator to strip off high frequency characteristics of the multiplied haversign signal to create a haversign signal; a first control circuit to compare a magnitude of the haversign signal to a magnitude of a first inductor current to generate a first drive signal; and a second control circuit to compare a magnitude of the haversign signal to a magnitude of a second inductor current to generate a second drive signal, which controls an inductor current waveform to form a substantially sinusoidal waveform that is in phase with the AC input voltage.