Patent ID: 7288901

Claim:
A ballast for powering at least one gas discharge lamp, the ballast comprising: an inverter having a normal operating frequency; an output circuit coupled to the inverter, the output circuit comprising output connections adapted for coupling to a lamp load comprising at least one gas discharge lamp; and an arc protection circuit coupled to the inverter and to the output circuit, wherein the arc protection circuit is operable: (a) to monitor an electrical signal within the output circuit for indication of an arc condition, wherein an arc condition is deemed to have occurred when the electrical signal includes a high frequency component having: (i) a magnitude that exceeds a predetermined threshold value; and (ii) a fundamental frequency that is on the order of at least ten times greater than the normal operating frequency of the inverter; (b) to provide a starting period wherein the inverter is enabled and allowed to attempt to start the lamp, independent of occurrence of an arc condition; (c) in response to occurrence of an arc condition after completion of the starting period: (i) to disable the inverter and to keep the inverter disabled for a shutdown period; and (ii) after completion of the shutdown period, to again provide the starting period whereby the inverter is enabled and allowed to attempt to start the lamp, independent of occurrence of an arc condition.