Monolithic clamping circuit and method of preventing transistor

Abstract

A monolithic clamping circuit (10) and a method of protecting a semiconductor power transistor (14) from entering avalanche breakdown. The semiconductor power transistor (14) controls the switching of an inductor (16). The monolithic clamping circuit (10) causes energy stored in the inductor (16) to be dissipated in the semiconductor power transistor (14). A voltage sense circuit (18) provides a feedback signal to a selector circuit (12) in response to a voltage at a collector terminal of the semiconductor power transistor (14). The selector circuit (12) switches the semiconductor power transistor (14) to the conductive mode when the feedback signal indicates a high voltage at the collector terminal of the semiconductor power transistor (14). Dissipating the energy stored in the inductor (16) while operating in the conductive mode prevents the semiconductor power transistor (14) from entering avalanche breakdown.