In this paper, we present the design and implementation of a high-efficiency flyback converter tailored for mobile phone chargers. 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 introduces synchronous rectification, minimizing output rectifier losses. The third generation, which is the focal point of this paper, further enhances efficiency by recycling leakage energy using a GaN switch and a recycling snubber circuit. This design achieved an experimental efficiency of 84.5% at 5W output power, 4% higher than the previous generation that does not use leakage recycling. The converter is expected to achieve an efficiency of 87-88% at full output power of 11W, outperforming Samsung chargers by up to 1.5% and Apple chargers by up to 15%. We plan to test the hardware at full power next to validate our prediction. Both simulation and experimental results confirm the effectiveness of the proposed design.
