1 kW LLC Resonant Converter with HV GaN Switches

Properties of the new high voltage (650 V) GaN HEMT cascodes are presented and compared with those of their silicon counterparts. The short switching times, low Qg and Coss along with low RDSon of GaN HEMTs make them ideal for high frequency DC/DC conversion. A 1kW, 400 V to 48 V LLC resonant DC/DC converter design is described and various design constraints are discussed. Presented waveforms and efficiency measurements prove the GaN HEMTs are the devices of choice for new high efficiency and power density designs.