Design and Implementation of Interleaved Flyback Converter with GaN E-HEMT

High efficiency, high power density, and small size has become the development trend of power converters. In this paper, an interleaved flyback DC-DC converter with wide input voltage range with the GaN high electron mobility transistor (HEMT) is implemented for achieving high power density. The interleaved flyback converter inherent with leakage energy recycle function can reduce the output current ripple to improve efficiency which is suitable for 1 MHz operation. In this paper, the operating principle and the steady-state characteristics of the interleaved flyback converter are analyzed. Also, the gate driver circuits design of GaN are discussed. Finally, an interleaved flyback converter with 1 MHz switching frequency laboratory prototype is implemented with input voltage range 72 V to 240 V, output voltage of 24 V, rated power of 144 W. In addition, the synchronous rectifiers are used at secondary side to reduce conduction loss for higher efficiency to verify the theoretical analysis. The experimental results show that the highest efficiency is 84.1% at 50%load with the input voltage of 72 V.