A Novel Bridgeless High-Frequency Resonant AC-DC Converter

This paper introduces a novel bridgeless resonant ac-to-dc converter, capable of efficiently converting arbitrary low-amplitude input voltages into a regulated dc voltage. High-frequency resonant operation owing to LC resonance allows small footprint for passive components, thereby increasing the circuit power density without suffering from switching losses. A resonant gate drive circuit is designed and utilized to further reduce gating losses under high-frequency switching and light-load conditions. The converter operates at fixed switching frequency, while it regulates the output voltage by using module on-off control with fast transient response. A 2MHz prototype is fabricated for validation of low power conversion. The maximum efficiency of the prototype is 66.3% at its rated output power of 500mW.