Monolithically Integrated Over-Temperature Protection Circuit Based on GaN HEMTs

Over-temperature protection is progressively being recognised as a crucial aspect of power converter design, driven by the growing demands for higher switching frequency and power density. This paper demonstrates a monolithically integrated over-temperature protection circuit that consists of only four p-GaN HEMTs, capable of controlling the power transistors of synchronous Buck converters. The proposed work includes temperature detection and protection circuits that can avoid high-temperature damage to GaN Buck converter circuits. Due to the simple structure of this design, the protection circuit exhibits a small chip area, which is 0.16 mm2. The protection circuit can accurately protect Buck converters at different temperatures by adjusting the supply voltage of the temperature detection circuit, which would be conducive to varying demands of GaN converter circuits. The experimental results demonstrate that the proposed work achieves over-temperature protection at 200 °C.