Power Switching

SiC and GaN devices can be switched at much higher frequencies than Si devices, leading to dramatically smaller transformers being required. A five times increase in the switching frequency from 20kHz to 100kHz means five times less volume and weight. Similarly the output filter components are reduced in size and weight. The diode conduction losses remain a problem for SiC devices and in practice both Si and SiC diodes are usually limited to 175°C operation and Si and SiC based power converter systems can require water-cooling. Due to our unique patented design approach GaN Systems diodes have very low conduction losses because of the relatively low voltage drop and their stability at high temperatures. Air-cooling is possible and substantial weight and size reductions can be achieved.

We expect to initially provide transistors and diodes with operating voltages from 100 to 1,000 volts, and able to handle currents between 3 and 300 Amps. To achieve conversion efficiently, very low voltage loss is a prime requirement. The lack of significant charge storage in GaN devices also allows for much higher switching speeds for power supplies and power factor correction circuits with consequently much smaller and energy-efficient products. The chart above provides a comparison of diode losses for the 5kW DC-DC power converter operating at 100kHz