| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection function in the case an abnormality occurs in the operation when a lamp is lighting driven regularly due to contact failure of a line supplying a power to the lamp except for a non-load state. SOLUTION: When a drive operation for regular lighting after starting a lamp is carried out, voltage value of the output of a DC/DC down converter 21 in a lighting drive circuit is detected. If the voltage value detected is outside of a range corresponding to regular operation, and if the state that is outside of a range obtained corresponding to a non-load state continues for a certain time or more, the operation of the DC/DC down converter is stopped, and power source supply to the lamp is stopped. COPYRIGHT: (C)2008,JPO&INPIT |
