Comparisons of Board-Side and Back-side Thermal Management Techniques for eGAN(R) FETs in a Half-Bridge Configuration.

Abstract:
GaN FET characteristics offer converter high power-density capabilities with fast switching and low on-resistance, however, they are physically smaller, and come in alternative package offerings, than their silicon counterparts. When employed in applications the result is higher heat flux density that limits the power processing capabilities of the converters. Various thermal strategies are necessary to leverage the potential of GaN FETs by lowering the thermal resistances both in a printed circuit board (PCB) and through external heat sinking. Configuration options using thermal vias, heat spreaders, heatsinks on either side of a PCB, and high-performance thermal interface materials (TIM) are investigated. Implementing these techniques can reduce thermal resistance from the junction to ambient (RthetaJA) by 30% without a heatsink and by over 60% with a heatsink.