A 20 kV, 125 kHz Photonically Driven Power MOSFET-like Device

The Optical Transconductance Varistor (OTV) represents a new class of power electronic device that is photonically controlled. It eliminates the traditional semiconductor control junction by exploiting the bulk photonic properties of wide bandgap (WBG) materials. Without drift region limitations, carrier excitation occurs on the order of picoseconds and in the bulk of the crystal; decay of the carriers is dependent on doping. Conductivity is therefore proportional to optical intensity so the device exhibits a transconductance-like property. The device is bi-directional and inherent optical isolation provides scalability in voltage and current capability. Recent testing demonstrated operation at 20 kV and 2.5 A at over 125 kHz switching frequency; our target is a 20 kV, 10 A device. The OTV has broad application in medical equipment, radar, and HVDC and other equipment for the Smart Grid, reducing energy losses and the size and cost of equipment. Device background, present status and future development are set forth.