Integrated SenseHEMT and Gate-Driver on a 650-V GaN-on-Si Platform Demonstrated in a Bridgeless Totem-pole PFC Converter

This work presents an integrated GaN senseHEMT structure and segmented gate-driver implemented using ON Semiconductor’s 650-V mixed-signal GaN-on-Si process. The senseHEMT element with 2500:1 sensing ratio is embedded within the 650-V power device for near-lossless current sensing, and the totem-pole driver utilizing low-voltage (LV) e-HEMTs is monolithically integrated with the device. The proposed design is verified in a bridgeless totem-pole power-factor-correction converter operating in boundary conduction mode. The converter is controlled by an FPGA-based hysteretic current-mode controller to achieve sinusoidal current shaping. The controller uses the senseHEMT in conjunction with a current DAC and a high-speed comparator to sense the peak and valley currents through the power HEMT. A set of minimum-sized high-voltage (HV) GaN devices protect the LV current-loop circuitry from the high voltages in the powerstage. Experimental results show sinusoidally-shaped input current synchronized with the ac input voltage, demonstrating dynamic functionality of the senseHEMTbased current-control loop to achieve power-factor correction.