GaN switches enable high performance architecture for USB-PD EPR Adaptors

The new USB-PD EPR standard aims at universal power adaptor able to work with wide input voltage range (100Vac to 240Vac) and provide output voltages ranging from 5V to 48V. Nevertheless, such wide operation voltage ranges challenge the power converter topologies used up to now. In this paper an innovative architecture using GaN switches is presented. It consists of an active boost power factor correction (PFC) followed by an asymmetrical half-bridge flyback converter (well-known as hybrid-fly-back). Its advantages with respect to state-of-the-art solutions are analyzed and the interaction between both stages to achieve optimum efficiency is described. The benefits of GaN switches in the hybrid flyback stage are explained. Finally, the results are demonstrated with a 240W prototype.