During PCIM Asia 2025 in Shanghai, Han Cui gave a poster presentation showcasing open-frame charger designs that proves when selectively enhanced, flyback topologies can effectively replace resonant converters in mid-power applications up to 400 W, offering a practical balance between performance and cost.

This paper introduces a hybrid switching control approach that maintains high efficiency across a wide load range. A 300 W implementation using a 750 V GaN primary switch and variable off-time PWM control achieves 93% efficiency without added complexity or significant cost increase. Design considerations for SR, ZVS, and WBG devices are examined.