Boosting Charger Efficiency: A GaN-Based Flyback Converter with Energy Recycling

In this paper, design and implementation of a high-efficiency flyback converter tailored for mobile phone chargers is presented. The proposed converter has been evolved through three generations, each addressing specific power loss challenges. The first-generation design utilized a standard flyback converter with an RCD clamp snubber, resulting in an efficiency of 76%. The second generation introduced synchronous rectification, minimizing output rectifier losses. The third generation, which is the focal point of this paper, further enhanced efficiency by recycling leakage energy using a GaN switch and a recycling snubber circuit. This design achieved an experimental efficiency of 88.6% at 10W output power, 4.6% higher than the previous generation that does not use leakage energy recycling. Additionally, it outperformed Samsung chargers by up to 2% and Apple chargers by up to 12.6%. The converter is simulated and implemented to validate its performance and efficiency and to verify the efficacy of the proposed concepts. Both simulation and experimental results confirm the effectiveness of the proposed design.