| 摘要 |
PROBLEM TO BE SOLVED: To prevent a driving of a pulse voltage generation circuit even if voltages on both ends of a lamp are raised and as a result, prevent an inter-transformer short circuit and a damage of a switching unit. SOLUTION: When a discharge lamp 3 is started up, a protection circuit 10 and a switch 704 detach an input winding wire 602 of a transformer 602 from a capacitor 703 of a snubber circuit 7 by electric circuit-based means. Thus, an impedance value of the snubber circuit 7 becomes large, and an input voltage to an input winding wire of the transformer becomes small. As a result, even if the discharge lamp is completing its service life and a lamp voltage rises, a starting up of the pulse voltage generation circuit 8 by an output voltage of the output winding wire 602 of the transformer can be prevented. COPYRIGHT: (C)2008,JPO&INPIT |
