Patent ID: 9116538
Filing Date: 2015-08-25
Classification: G05F,H02M,Y02B,Y02P

Abstract:
1. A power factor correction (PFC) controller, comprising: a first current source coupled to generate a first current that is representative of an instantaneous input voltage of a PFC converter; a first capacitor coupled to be charged with a difference between the first current and a reference current when a power switch of the PFC converter is off; an error amplifier to be coupled to receive a feedback signal and to generate an error signal in response thereto, wherein the error signal is representative of a load condition at an output of the PFC converter; a switching frequency adjuster coupled to the error amplifier to generate an adjusted error signal in response to the error signal; a first comparator coupled to compare a voltage on the first capacitor with the adjusted error signal and to generate a first signal to end an off time of the power switch; and a drive signal generator coupled to the first comparator and configured to control an input current waveform of the PFC converter to substantially follow a shape of an input voltage waveform of the PFC converter by generating a drive signal in response to the first signal to control switching of the power switch, wherein the switching frequency adjuster changes a magnitude of the adjusted error signal in response to changes in a magnitude of the error signal to adjust an average switching frequency of the power switch.