| 摘要 |
PROBLEM TO BE SOLVED: To provide an effective means to restrain acoustic resonance in lighting a discharge lamp at a high frequency. SOLUTION: A discharge lamp lighting circuit includes a direct current-alternating current converting circuit 3, a starting circuit 4, controlling means 15 for controlling power, switching elements 5H, 5L driven by the controlling means 15, and a series LC resonance circuit (7p, 8, 9). A frequency modulating circuit is provided for restraining acoustic resonance by modulating a frequency of driving the switching element. When a basic frequency related to the drive frequency is equal to or higher than 1 MHz, a modulation width is set to be equal to or higher than 20 kHz. COPYRIGHT: (C)2007,JPO&INPIT |
