Patent ID: 7768755

Claim:
An electronic ballast for a gas discharge lamp, comprising: an inverter; a shut-down circuit coupled to the inverter; a safety circuit coupled to the inverter and to the shut-down circuit so that when a safety threshold is exceeded, the safety circuit is operable to instruct the shut-down circuit to disable the inverter until the ballast is reset; a monitoring circuit operably coupled to the inverter, the safety circuit, and the shut-down circuit so that during normal inverter operating conditions the monitoring circuit is operable to prevent the safety circuit from disabling the inverter; an overvoltage protection circuit coupled to the monitoring circuit, the inverter, and the shut-down circuit; the overvoltage protection circuit is responsive to an overvoltage condition outside of the normal inverter operating conditions by causing the shut-down circuit to disable the inverter and the monitoring circuit until the overvoltage condition ends, and if the overvoltage condition cannot be corrected after a predetermined sequence, the safety circuit is operative to cause the shut-down circuit to disable the inverter until the ballast is reset; and wherein the inverter is operable to attempt to re-strike the lamp following disablement of the inverter by the overvoltage protection circuit if the safety threshold has not been exceeded.