Analysis and Design of a 2 MHz GaN-based Active-Clamped Isolated SEPIC Converter for Low-Power Automotive Subnets

This paper addresses the analysis, design and implementation of a 2 MHz, 12 V, 600 mA, GaN-based Active-Clamped Isolated SEPIC Converter (ACISC) supporting full ZVS throughout the 9V-18V automotive range and intended to provide isolation and power interface between the 12V battery and the low-power subnet. Designed for resonant DCM operation and leveraging the high switching frequency enabled by GaN devices, the selected topology leads to a strong reduction in total magnetic size and footprint while maintaining a high efficiency profile. This paper aims at showing the theoretical model specifically developed for full ZVS resonant DCM operation of the ACISC converter together with the design and implementation of the transformer. The proposed model has been verified through simulations as well as experimental measurements taken on a 7.2 W GaN-based prototype employing a planar transformer.