Apple Inc.
Forward Mode Soft Switching Resonant Converter

Abstract:

A forward mode, soft switching, resonant power converter may include a resonant circuit having an input and an output. A main switch may couple the input to a DC input voltage. An auxiliary switch may couple the input to ground. A rectifying component may be coupled between the output of the resonant circuit and an output of the power converter. The main and auxiliary switches may be operated to alternately couple the input terminal to the DC input voltage and ground, thereby converting the DC input voltage to an output voltage of the converter. Resonance may allow for the main and auxiliary switches to be closed under zero voltage switching conditions. The main and auxiliary switches may be operated at a fixed switching frequency, and a duty cycle of the main switch may be increased in response to increased load on the converter.