| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent abnormal heat generation even if any fault occurs in a feed line to a high pressure discharge lamp or the discharge in outer tube occurs in the high pressure discharge lamp. <P>SOLUTION: Although direct current output voltage of a step-down chopper circuit 3 declines from voltage of non-lighting time or no-load time by discharge generated in a conductor 105a of a cable 104, a lighting distinction part 26a does not wrongly determine such discharge as the discharge in the high pressure discharge lamp 4. Accordingly, continuous discharge does not occur in the conductor 105a by continuing the operation of a timer part 29 to intermittently apply high pressure pulse voltage and the abnormal heat generation of the cable 104 can be prevented. Since the lighting distinction part 26a does not wrongly determine it as a lighting condition when the high pressure discharge lamp 4 generates the discharge in outer tube, the abnormal heat generation of each part, a socket 102, etc. can be suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
