Monolithic GaN Power ICs Enable High Density High Frequency 3.2 KW AC-DC Rectifier

A 3.2KW 240VAC-to-48VDC high-density rectifier has been designed, built and tested. The topology selected includes an interleaved totem-pole power factor correction (PFC) front end, a resonant LLC step down converter, and a synchronous rectification (SR) output stage. The power train consists of GaN Power ICs with integrated gate drive operating at frequencies of 1MHz and has enabled an overall power density target of 70 W/in3. The GaN power IC waveforms demonstrate clean and fast zero-voltage operation in all stages and the prototype has reached peak efficiencies of 99% in the PFC stage and 98.3% in the LLC/SR stage.