Increasing the switching frequency of GaN HFET converters

GaN-on-Si switches, hard-switching 400V at 1MHz, have demonstrated power conversion with 96% efficiency, outperforming Si MOSFETs. This performance was achieved using hybrid integration of bare GaN and gate driver die, resulting in clean waveforms with a slew rate of 100V/ns. The new Si Super-Junction (SJ) MOSFETs have a hard-switching figure-of-merit (FOM) which is approaching that of GaN HFETs. However, GaN´s FOM for soft-switching is more than 9X better than Si SJMOSFET. Using this FOM, GaN ICs in 400V soft-switching converters are predicted to switch beyond 100MHz.