Switch control circuit and resonant converter including the same

摘要

A resonant converter includes a primary-side winding electrically coupled to an input voltage, a secondary-side winding electrically coupled to a load, first and second switches coupled to one end of the primary-side winding, and a switch control circuit configured to differently control switching frequency limit ratios of the first and second switches by differently limiting a frequency variation ratio of a first clock signal that determines switching frequencies of the first and second switches according to variation of one of the input voltage and the load.

主权项

1. A switch control circuit for controlling switching operations of first and second switches that control power supply of a resonant converter, the switch control circuit comprising:
a half cycle signal generator to generate a half cycle signal according to a result of comparing a comparison voltage corresponding to an output voltage of the resonant converter to a first signal based on a current sense voltage according to a load of the resonant converter; and a frequency limit controller to differently limit a variation ratio of a frequency of a first clock signal according to a result of comparing a target on-time based on a first enable period in a previous switching cycle of a first clock signal for determining switching frequencies of the first and second switches to a first period beginning from an enable start time point of the first clock signal and ending at a point in time at which the half cycle signal is generated.