This paper presents a design of high-frequency Boost PFC with AHB Flyback converter for a PD3.1 adapter application. Each design procedure targets minimal power loss and highest power density. The boost-follower PFC improves low line efficiency by adjusting bus voltage. The new SR VCC supply circuit simplifies the complexity and reduces the driving loss significantly at high output voltage condition. More importantly, the new GaNFast power ICs with GaNSense and GaN half-bridge power ICs reduce switching loss and circulating energy, and significantly improve system efficiency and power density. The prototype verifies the advantages of the system design.
