| 摘要 |
PURPOSE:To light a discharge lamp in a consistently stable manner by hardly generating acoustic resonance during lighting the lamp with no complication of a circuit. CONSTITUTION:Several switching elements are turned on and off and a DC current is intermittently supplied to a resonance circuit via the turned-on switching elements to develop high frequency voltage, with which a discharge lamp is lit. The resonance circuit (equivalent to resonance coils L1, L2 and capacitors 12, 12-1, 12-2 or a capacitor 11 when the sufficiently large capacitors 12-1, 12-2 are selected) which has different impedance values depending on the flow direction of a high frequency current in the discharge lamp, and a control circuit (equivalent to a control signal generation section 19) to control the ON/OFF of the switching elements so that ON/OFF time periods for the switching elements can be different for every switching element are provided. |
