Comparison and optimization of high frequency inductors for critical model GaN converter operating at 1MHz

The Gallium Nitride (GaN) devices have been attractive due to its low loss and high switching speed. With the soft switching, for example critical mode operation, the GaN converter can be further pushed over MHz range. How to design the critical mode inductor at such switching frequency is a challenge, because the loss on the inductor is a big concern for the converter efficiency. This paper experimentally and numerically evaluates different core materials and structures, winding types and structures. The best candidate can reduce the inductor loss below 3W for a 1kW critical mode converter operating at 1MHz.