Pre-distortion of sensed current in a power factor correction circuit

摘要

An example controller includes a power factor enhancer, an on-time controller, and a switching signal generator. The power factor enhancer is coupled to generate a pre-distortion signal each half-line cycle of an ac input voltage of a PFC converter. The on-time controller ends an on-time of a PFC switch in response to a sensed PFC switch current of the PFC converter multiplied by the pre-distortion signal. The switching signal generator controls an input current waveform of the PFC converter to substantially follow a shape of an input voltage waveform by generating a switching signal in response to the on-time controller to control switching of the PFC switch. The power factor enhancer adjusts the pre-distortion signal to pre-distort the sensed PFC switch current to compensate for distortion in the input current waveform.

主权项

1. A controller for use in a power factor correction (PFC) converter, the controller comprising:
a power factor enhancer coupled to generate a pre-distortion signal each half-line cycle of an input voltage of the PFC converter; an on-time controller configured to generate a first signal to end an on-time of a switch of the PFC converter, wherein the first signal is generated in response to a sensed input current of the PFC converter multiplied by the pre-distortion signal; a switching signal generator coupled to the on-time controller 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 switching signal in response to the first signal to control switching of the switch, wherein the power factor enhancer adjusts the pre-distortion signal to pre-distort the sensed input current to compensate for distortion in the input current waveform; and an input voltage detector coupled to the power factor enhancer to generate an input voltage signal that is representative of a value of the input voltage of the PFC converter, wherein the pre-distortion signal is representative of the value of the input voltage multiplied by a variable multiplication factor, and wherein the power factor enhancer adjusts the multiplication factor to pre-distort the sensed input current, wherein the power factor enhancer adjusts the variable multiplication factor to be greater than one for a first part of a half-line cycle of the input voltage and less than one for a second part of the half-line cycle to pre-distort the sensed input current.