| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting circuit for a projector, with high convenience as a portable unit driven by both a commercial power source and a battery. SOLUTION: The circuit for lighting a high-pressure discharge lamp 14 is provided with a DC-DC converter 1 outputting direct-current voltage by boosting direct-current voltage, an AC-DC converter 10 outputting direct-current voltage by rectifying alternate-current voltage, an input changeover circuit 2 and a power changeover circuit 3 for switching between the above, a stable lighting circuit 11 stably lighting the high-pressure discharge lamp 14, a power control part 12 for controlling power supply from the stable lighting circuit 11 to the high-pressure discharge lamp 14, and a lighting start-up circuit 13 for starting and lighting the high-pressure discharge lamp 14, as well as the high-pressure discharge lamp 14. The power changeover circuit 3 switches power so as to supply relatively low power to the high-pressure discharge lamp 14, when a direct-current power source is connected to only the DC-DC converter, and relatively high power, when a commercial alternate-current power source is connected to at least the AC-DC converter. COPYRIGHT: (C)2007,JPO&INPIT |
