This paper proposes improved PCB design techniques for converters using GaN HEMTs. An isolated DC-DC converter designed for high-temperature (>150 ℃) applications- such as defense, oil and gas, etc.- is considered as the test case for validating the proposed concepts. The primary focus of this paper is to address the challenge of reducing voltage spikes in the drain-to-source voltage (Vds) by minimizing parasitic elements, thereby improving voltage quality in high power density GaN HEMT designs. The proposed ‘closed-form’ layout for a half-bridge configuration effectively decreases the parasitic inductances, a significant stride in enhancing voltage stability and overall device performance. Ansys (Q3D analysis) simulations, for the conventional designs and the proposed closed-form layout are done and results are compared. These simulation results are validated through hardware experiments, providing comprehensive confirmation of the design's effectiveness by showing substantial reduction in the Vds spikes compared to previous GaN designs. All tests were done at 175 °C on a PCB designed for HT application, showing the proposed design’s robustness under extreme conditions.
