| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting circuit capable of detecting capacitance drop of an electrolytic capacitor and thereafter never carrying a current to the discharge lamp lighting device. SOLUTION: A microcomputer 10 inputs, from an input terminal 13, a voltage of the electrolytic capacitor 6 converted in level by a voltage conversion circuit 9, determines its pattern, determines that the capacitance of the electrolytic capacitor 6 drops when the pattern coincides with a determination criterion, and outputs a signal for forcibly turning on a switching element 12 to a switching element driving circuit 11 from an output terminal 14. The switching element driving circuit 11 turns on the switching element 12 in response to the signal from the microcomputer 10. As a result, an overcurrent is generated in the direction shown by an arrow 15, an overcurrent protection element 2 is melted down, and this discharge lamp lighting circuit 100 is disconnected from a power source 1. COPYRIGHT: (C)2007,JPO&INPIT |
