Series Capacitor Converter with MHz Switching Frequency Based on GaN HEMT

This paper applies GaN HEMT to series capacitor buck converters and increases the switching frequency to 1MHz, greatly improving the power density of the converter. The advantages brought by the new wide-bandgap semiconductor device were analyzed, the driving circuit was optimized, and a 1MHz improved two-phase Buck high-frequency converter with 48V input, 12V/240W output and peak efficiency of 98.5% was designed and built. The effective power density reaches 218.5 W/in ³ .In the rated state, the efficiency of the prototype is 93.4%.