Non zero-voltage switching protection circuit

Abstract

A protection circuit for preventing non zero-voltage switching of a lamp resonant output circuit driven by upper and lower half-bridge switches. The protection circuit includes a sense resistor disposed between the lower half bridge switch and ground for developing a voltage corresponding to the current flowing through the lower switch. A comparator compares the voltage developed across the sense resistor against a fixed reference voltage and generates an output indicative of a non zero-voltage switching condition when the voltage across the sense resistor exceeds the fixed reference voltage. A latch is connected to the output of the comparator and generates a latch output signal which disables the generation of drive signals to the upper and lower switches in the event of a non zero-voltage switch condition.

Dependencies are inferred from the claim text.