Patent ID: 8736246

Claim:
A power factor control circuit comprising: an input terminal, an output terminal, an inductor, an output capacitor, a diode, an active switch, and a power factor controller connected to the input terminal and the output terminal of the power factor control circuit, and having an output control terminal connected to the active switch; wherein the power factor controller has: a voltage loop control module generating a reference current according to a difference value between an output voltage of the power factor control circuit and a reference voltage, and having a continuous current mode (CCM) proportional integral amplifier and a discrete current mode (DCM) proportional integral amplifier; a current loop control module connected to an output terminal of the voltage loop control module and the power factor control circuit, outputting pulse width modulation (PWM) signals to the active switch, having a continuous current compensation unit and a discrete current compensation unit, and generating a current compensation parameter under a CCM or a DCM according to a difference value between a reference current and an inductor current; and a feed-forward control module determining if the power factor control circuit is operated at the CCM or the DCM, generating a feed-forward control parameter under the CCM or the DCM, sending the feed-forward control parameter to the current loop control module, switching to the CCM proportional integral amplifier or the DCM proportional integral amplifier in the voltage loop control module, and switching to the continuous current compensation unit or the discrete current compensation unit in the current loop control module under the CCM or the DCM; and wherein a duty cycle of each PWM signal is equal to a sum of a corresponding feed-forward control parameter generated by the feed-forward control module and a corresponding current compensation parameter generated by the current loop control module.