| 摘要 |
A discharge lamp lighting circuit 1 includes a direct current-alternating current converting circuit 3 , a starting circuit 4 , controlling means 15 for controlling power, switching elements 5 H, 5 L driven by the controlling means 15 and a series LC resonance circuit ( 7 p , 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.
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