Compact GaN Power Modules with Direct Bonded Liquid-Cooled Heat Exchanger Suitable for EV Applications

In this paper, a direct bonded GaN intelligent power module (IPM) with liquid cooling is demonstrated. A half bridge module with GaN high electron mobility transistors (HEMTs) is bonded on active metal brazed (AMB) substrates which are pre-brazed on a copper liquid-cooled heat exchanger. The design of this power module, such as the selections of the GaN dies and the placement of the GaN dies with respect to the AMB dimensions, is determined based on thermal simulations, estimated electrical parasitics and experiments. The prototype GaN IPMs are demonstrated in a buck converter configuration. The modules are tested up to 110 W with top surface temperature of the PCB module kept below 125°c, measured by an infrared camera (FLIR). The proposed IPM with liquid cooling offers an effective packaging solution for electric vehicle applications.