Patent ID: 8410713

Claim:
A lamp driver circuit comprising: an inverter circuit to selectively energize one or more lamps, the inverter circuit having a transformer to provide voltage to the one or more lamps, the transformer having a primary winding connected to a direct current (DC) voltage bus and a secondary winding to connect to one or more lamps; a filter connected to the primary winding to receive a primary winding signal representative of the voltage across the primary winding, wherein the primary winding signal has a frequency spectrum and the filter detects a particular characteristic of the frequency spectrum of the primary winding signal, and wherein the particular characteristic of the frequency spectrum is indicative of an end of life (EOL) condition of the one or more lamps; and a control circuit connected to the inverter circuit and to the filter, wherein the control circuit is configured to discontinue energizing of the one or more lamps by the inverter circuit when the particular characteristic of the frequency spectrum of the primary winding signal is detected by the filter.