Thermal Design Considerations for GaN-Based Power Adapters

Gallium Nitride enhancement-mode high electron mobility transistors (GaN E-HEMTs) have paved the way to enable high power density and high efficiency in power adapters. As power density and low profile increase in popularity, more attention to thermal management inside the adapter increases. This paper presents some general design rules for the thermal management of GaN-based power adapters. Moreover, a mutual thermal resistance study is conducted to break down the impact of individual heat sources on the GaN device. This enables the designers to prioritize the thermal optimization based on the contribution of each heat source to the overall thermal resistance. A GaN Systems reference design is studied in this paper. The analyses are conducted using the finite element method (FEM). Simulation and experimental results are employed to verify the concepts studied in multi-heat source power adapters.