Texas Instruments Incorporated
Direct conduction control for power factor correction circuit

Abstract:

A system includes a switching power supply that includes switch devices configured to provide a regulated output voltage based on an input voltage. A controller is configured to control the switch devices based on a power demand signal. A direct conduction avoidance circuit is configured to provide a direct conduction avoidance signal based on the regulated output voltage exceeding a direct conduction threshold voltage. The direct conduction avoidance signal is combined with a compensation signal to provide the power demand signal to the controller. An override circuit is configured to disable the direct conduction avoidance circuit based on the input voltage of the switching power supply being below an override threshold voltage.