| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting circuit capable of detecting an abnormality occurring synchronized with a lighting period of the discharge lamp. SOLUTION: A drive voltage generating part 12 supplies a drive voltage VL to a discharge lamp 4 of driving object with a prescribed lighting period. A monitoring circuit 10 monitors a current IL flowing in the discharge lamp 4 and detects an abnormality of the discharge lamp 4. The monitoring circuit 10 detects the abnormality of a discharge lamp 4 with a condition that the size of a drive current IL flowing in the discharge lamp 4 becomes smaller than a prescribed value in a first period in which the drive current IL flows in a first direction in the discharge lamp 4 out of the lighting period, and detects the abnormality of the discharge lamp 4 with a condition that the size of the drive current IL flowing in the discharge lamp 4 becomes smaller than the prescribed value in a second period in which the drive current IL flows in an opposite direction to the first direction in the discharge lamp 4 out of the lighting period. COPYRIGHT: (C)2010,JPO&INPIT |
