GaN 800V Module with Double Sided Cooling in a 3L Half Bridge Configuration
Recent years witnessed the increment of the EV battery voltage from 400V to 800V. To use 650V GaN devices for 800V, a three-level NPC topology is a viable solution. To further reduce the loop parasitics and enhance the thermal capability, power module solutions instead of discrete switches are needed. With the success of such power modules, we expect to see the immediate use in 800V EV battery charger and inverters.
Packaging Approach of the 800V/300A GaN 3L Bridge
Advanced low inductance packaging and chip interconnect on a DBC sintered design or similar isolated set-up is the primary target. The goal is to investigate several options to physically place the bare dies or chip-scale pre-packaged dies on the substrate ensuring low inductance of the overall package. Different chip packaging technologies (die attach, wire bonding/ribbons, Ag sintering, pre-packaging) and process challenges with respect to fabrication is to be investigated. Substrate selection and trade-off (incl. organic substrates) with respect to electric/thermal properties and thermal reliability as well as process handling in production. It is desired to have different designs with different materials ready for power and thermal cycling tests. A criterion for evaluation is the breakdown voltage on one side and the expected relative thermal resistance change after power/thermal cycling on the other side.
How WBG Can Help
The success of this project provides a high-current (>300A) and high-voltage (>800V) GaN power modules, extends the applications of GaN from low-voltage applications to high voltage. It also helps the team to understand the loss mechanism, low inductance design as well as cost effective realization and manufacturability.
- Nathan Strain