| 摘要 |
PURPOSE: To provide a power unit in which the lighting failure of a discharge lamp by momentary service interruption of an AC power source can be prevented, and the miniaturization and reduction in cost can be also attained. CONSTITUTION: A DC voltage obtained by rectifying and smoothing an AC power source AC through a filter circuit 1, a rectifier 2, and a booster chopper circuit 3 is converted into a AC high frequency voltage by an inverter circuit 4, and supplied to a discharge lamp La. The DC voltage obtained by rectifying and smoothing the AC power source AC through the filter circuit 1, the rectifier 2 and the chopper circuit 31 is also charged in capacitance elements C2 -Cn . At the momentary service interruption of the AC power source AC, the voltage Vc2 between both ends of the capacitance elements C2 -Cn is supplied to the inverter circuit 4 through a diode D3 , whereby the unlighted state of the discharge lamp La is prevented. Thus, a power unit in which the lighting failure of the discharge lamp by the momentary service interruption of the AC power source can be prevented, and the miniaturization and reduction in cost can be also attained can be provided. |
