Clean-tech semiconductor company Cambridge GaN Devices (CGD) has revealed more details about a solution that will enable it to address EV powertrain applications over 100kW – a market worth over $10-billion – with its ICeGaN gallium nitride (GaN) technology. Combo ICeGaN combines smart ICeGaN HEMT ICs and IGBTs (Insulated-Gate Bipolar Transistors) in the same module or IPM, maximizing efficiency and offering a cost-effective alternative to expensive silicon carbide (SiC) solutions.
“Today, inverters for EV powertrains either use IGBTs which are low cost but inefficient at light load conditions, or SiC devices which are very efficient but also expensive. Our new Combo ICeGaN solution will revolutionise the EV industry by intelligently combining the benefits of GaN and silicon technologies, keeping cost low and maintaining the highest levels of efficiency which, of course, means faster charging and longer range. We are already working with Tier One automotive EV manufacturers and their supply chain partners to bring this technology advancement to the market.”
Dr Giorgia Longobardi, Founder and CEO of CGD
The proprietary Combo ICeGaN approach uses the fact that ICeGaN and IGBT devices can be operated in a parallel architecture having similar drive voltage ranges (e.g. 0-20 V) and excellent gate robustness. In operation, the ICeGaN switch is very efficient, with low conduction and low switching losses at relatively low currents (light load), while the IGBT is dominant at relatively high currents (towards full load or during surge conditions). Combo ICeGaN also benefits from the high saturation currents and the avalanche clamping capability of IGBTs and the very efficient switching of ICeGaN. At higher temperatures, the bipolar component of the IGBT will start to conduct at lower on-state voltages, supplementing the loss of current in the ICeGaN. Conversely, at lower temperatures, ICeGaN will take more current. Sensing and protection functions are intelligently managed to optimally drive the Combo ICeGaN and enhance the Safe Operating Area (SOA) of both ICeGaN and IGBT devices.
ICeGaN technology allows EV engineers to enjoy GaN’s benefits in DC-to-DC converters, on-board chargers and potentially traction inverters. Combo ICeGaN further extends the benefits of CGD’s GaN technology into the rich 100+ kW traction inverter market. ICeGaN ICs have been proven to be very robust and IGBTs have a long and proven track record in traction and EV applications. Similar, proprietary parallel combinations of ICeGaN devices with SiC MOSFETs have also been proven by CGD, but Combo ICeGaN – which is now detailed in a published IEDM paper – is a far more economical solution. CGD expects to have working demos of Combo ICeGaN at the end of this year.
