Switching transient shaping of RF power MOSFETs for a 2.5 MHz, three-phase PFC

To increase the power density of active rectifiers, the switching frequency and switching-speed have to be raised considerably. However, the very fast switching transients induce a strong voltage and current ringing. In this paper, a novel magnetically coupled damping layer is introduced for attenuating these unwanted oscillations. The proposed damping layer can be implemented using standard materials and printed circuit board manufacturing processes. The system behavior is analyzed in detail and design guidelines are given. The effectiveness of the introduced layer is determined by layout parasitics, which are calculated with the partial element equivalent circuit method and compared to impedance measurements. The performance of the damping layer is demonstrated by simulations and verified via measurements on a laboratory prototype.