GaN-Based Active Clamp Flyback Converter Realizing Soft-Switching over Wide Voltage Range through Auxiliary Leakage Inductor

Active clamp flyback (ACF) converters commonly take magnetizing inductor energy to realize zero-voltage-switching (ZVS) in low output power. However, the output power could be improved by realizing ZVS through the leakage inductor. This paper analyzes the detailed operation principle with the consideration of parasitic parameters, then presents a design and debugging process by adding auxiliary leakage inductance to help realize ZVS over wide voltage range. The effectiveness of auxiliary leakage inductance design is verified with a 200W prototype working at 500kHz.