Ionizing Dose-Tolerant Enhancement-Mode Cascode for High-Voltage Power Devices

An enhancement-mode cascode power device topology is described in which a high-voltage commercial device is used in conjunction with a low-voltage radiation-tolerant device to enable a switch that functions well at high total ionizing dose. Although the threshold voltage of the commercial high-voltage power transistor changes significantly with ionizing dose, the threshold voltage of the input device is relatively constant and presents a stable load to the power device drive circuit. Experimental data showing stable input characteristics for the composite devices are presented.