Patent ID: 7183721

Claim:
A ballast circuit for powering a lamp, said circuit comprising: a direct current (DC) bus; an inverter circuit coupled between the DC bus and the lamp; a control circuit for controlling the inverter circuit to provide power to the lamp and for initiating an ignition cycle in order to ignite the lamp; and a detection circuit connected to the inverter circuit and responsive to the control circuit for detecting a detection signal indicative of an arc, and for generating a command signal provided to the control circuit for inhibiting the control circuit from providing power to the lamp, the detection circuit comprising: a sensing circuit connected to the inverter circuit for sensing a magnitude of the detection signal, wherein the magnitude is indicative of an arc, and generating the command signal to be provided to the control circuit for inhibiting the control circuit from providing power to the lamp when the magnitude of the detection signal exceeds a threshold value; and a switching circuit responsive to the control circuit and coupled to the sensing circuit for disabling the sensing circuit when the control circuit initiates the ignition cycle.