| 摘要 |
PURPOSE: To prevent starting voltage from being generated before a safety circuit is reset. CONSTITUTION: A safety circuit 32 is reset when an NPN transistor 28 is turned off, and detects voltage applied to a discharge lamp 31 after the second time passes after starting voltage is supplied from a starting circuit 26 in a reset condition, and switches an electric power supply switch SW11 to an OFF condition when this detected result exceeds a preset value. The time until the NPN transistor 28 is put in an OFF condition after DC electric power supply voltage of a reset circuit 27 is applied, is set sufficiently shorter than the time until the starting voltage is generated after DC electric power supply voltage of the starting circuit 26 is applied. Therefore, the starting voltage can be prevented from being generated before the safety circuit is reset. |
