650V Half-bridge GaN with Integrated Driver for 1kW Motor Drive Applications without Heatsink

Abstract:
This paper introduces a half-bridge power stage composed of two enhancement-mode GaN HEMTs, featuring dedicated gate drivers and a high-voltage bootstrap switch. The design incorporates advanced bi-directional current sensing while maintaining low standby power consumption. The integrated shuntless and loss-less current sensing enables over-current protection (OCP) and short-circuit protection (SCP), along with under-voltage lock-out (UVLO) and over-temperature protection (OTP). Additionally, the driving strengths of both the low-side and high-side transistors can be adjusted to easily meet EMI standards. A 650V half-bridge GaN device in a thermally optimized QDPAK package has been developed, demonstrating a temperature rise of less than 40deg C for the GaN IC. Consequently, the heatsink can be eliminated in the motor drive stage for typical 1 horsepower (HP) washing machines and cloth dryers.