GaN chips edge into SiC space

VisIC’s prototype inverter shows that GaN devices can be used in parallel


VisIC Technologies has successfully tested its 2.2 mΩ 650 V half-bridge power module with a mainstream permanent magnet synchronous motor (writes Nick Flaherty).

The module consists of four parallel 8 mΩ direct drive D-mode gallium nitride (GaN) power transistors in a three-phase configuration, and was connected to a PMS motor used by a major automotive OEM for a battery EV platform.

The inverter phase current reached 350 Arms (500 A peak) at 400 V, although the test system’s limitations prevented higher currents. The demonstration is key to showing that GaN devices can be used in parallel and handle the oscillations caused by fast-switching transient currents; in the past, silicon carbide transistors were needed for such designs.

The demonstration used the WLTP driving cycle and achieved an efficiency comparable with commercial SiC modules. GaN transistors enable lighter, smaller power systems and a smaller battery without compromising the driving range, and is more cost-effective than SiC.

The prototype system will be available for testing across additional customer sites towards the middle of this year.