IEEE Workshop on Wide Bandgap Power Devices and Applications in Asia (WiPDA Asia 2018)

212 / 2017-11-21 05:53:03

High-Power-Density 400VDC-19VDC LLC Solution with GaN HEMTs

GaN,LLC,DCDC,High power density,HEMT

Plenary track > Hard-switched and soft-switched applications

Compared to Silicon MOSFETs, GaN High-electron-Mobility Transistors (GaN HEMT) features significantly reduced gate charge (Qg) and output capacitance (Coss), resulting in lower driving loss and shorter deadtime. Therefore, GaN HEMTs show significant advantages over Silicon MOSFETs in high-frequency soft-switching resonant topologies such as an LLC resonant converter. With the increased switching frequency (Fsw), the transformer core size can be reduced. Furthermore, 3-D PCB structure is employed to increase the power density. A 190-Watt 400V-19V (GaN Systems E-HEMT based) LLC DC-DC resonant converter is carefully designed, and the transformer is optimized for high-end adapter applications operating above 600kHz. The prototype shows a complete design with a power density over 63W/inch3 (400V bus capacitor is included) while its peak efficiency has achieved 96%.