Hybrid Double-Side Cooled Package for Multichip GaN Power Module with Optimal Current Sharing at High Switching Speed

To expand current rating and facilitate the use of gallium nitride (GaN) high-electron-mobility transistors (HEMTs) in high power applications, multichip GaN power modules with paralleled GaN HEMTs are urgently needed. Existing GaN packages mainly focus on lowering inductances and thermal resistances, rarely involving current sharing. For multichip GaN modules, the package also requires more flexible layouts to achieve symmetrical layouts for current sharing, which is more challenging. In this paper, we propose a novel hybrid double-side cooled (DSC) package, where flexible printed circuit board is heterogeneously integrated to expand the layout flexibility and GaN HEMTs can be cooled on both sides. The flexible layout allows the entangled power and gate layouts of paralleled GaN HEMTs to be separated and optimally laid out. Based on this package, decoupled switching cells and integrated gate drivers are implemented in the multichip GaN module, enabling consistent layouts and low inductances. And the scaling of current ratings can be easily realized. The electromagnetic coupling, thermal performance and reliability are also analyzed in detail. By experiments, the multichip GaN hybrid DSC module has good insulation properties and ensures current sharing at switching speeds up to -29.3 A/ns and 204 V/ns. In addition, the thermal verification and applied weight experiment are also carried out.