T5 lamp end of life protection circuit

Abstract

Provided are an end-of-life protection circuit for a non-isolated electronic ballast and a method for protecting same. The non-isolated electronic ballast includes a driver circuit (104), a sampling circuit (108), and a control circuit (102). The driver circuit (104) connects to an output circuit (106) for controlling operation of a load. The sampling circuit (108) samples direct current (DC) voltage values of a capacitor of a lamp coupled to the ballast to detect occurrence of an asymmetric event. The control circuit (102) receives a voltage value in response to detecting the asymmetric event and outputs to the driver circuit (104) a control signal to control operation of the driver circuit (104) to prevent end-of-life damage. Provided also are an end-of-life protection circuit for an isolated electronic ballast and a method for protecting same.

Dependencies are inferred from the claim text.