| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that, when abnormalities are detected in an erroneously entered inspection mode, a discharge lamp drive is kept stopped. SOLUTION: In the light source (discharge lamp) lighting circuit, a mode distinction circuit 32 judges that an inspection mode is required when a current IL flows in a discharge lamp 4 during a mode distinction period, and a normal operation mode is required when not. A fail-safe timer circuit 36 detects in the inspection mode that an operation is abnormal unless a drive voltage VL reaches an abnormality detection voltage after a second abnormality detection period shorter than a first abnormality detection period of the normal operation mode elapses after a power source is inputted. A retry circuit 38 changes a state of the discharge lamp lighting circuit into one for stopping drive of the discharge lamp 4 if abnormalities of operation is detected in the inspection mode, and later, makes the mode distinction circuit 32 judge the mode. COPYRIGHT: (C)2011,JPO&INPIT |
