Switching frequency modulation for GaN-based power converters

Abstract

The effects on the EMI spectrum for various switching frequency modulation (SFM) scenarios in a high frequency boost converter are investigated in this paper. A GaN-device and a Si-device are compared with respect to their EMI behavior, which results from different gate charges and therefore different voltage gradients dv/dt on the power lines. First, the dynamic characteristics of the GaN-HEMT are demonstrated in detail. Then the behavior in the time domain and the frequency domain for switching operations at 300 kHz with various frequency modulation settings and an output power of 250 W are presented.