US Patent 9871510 Clamp for a hybrid switch

A cascode switch circuit includes a normally-on device cascode coupled to a normally-of device between first and second terminals of the cascode switch circuit. A leakage clamp circuit is coupled between first and second terminals of the normally-off device. The leakage clamp circuit is coupled to clamp a voltage at an intermediate terminal between the normally-on device and the normally-off device at a threshold voltage level. The leakage clamp circuit is further coupled to clamp a voltage between the second terminal of the normally-on device and the control terminal of the normally-on device at the threshold voltage level to keep the normally-on device off when the normally-on device and the normally-off device are off.