| 摘要 |
PURPOSE:To prevent afterglow by providing a preset control circuit, and immediately stopping the superimposition of a DC current based on an off-signal in a lighting device superimposing the DC power to maintain discharging in superimposition over the lighting by the high-frequency power. CONSTITUTION:The discharging of a discharge lamp 1 is maintained by the DC power obtained Via a diode D7 or the like in superimposition over the lighting by the high-frequency power oscillated via transistors Q1 and Q2. A transistor Q3 is provided on a discharging main circuit and operated via a voltage detecting circuit 7. When a switch SW is opened to turn off the discharge lamp 1, a control power source VC4 is reduced, a diode ZD2 is de-excited, and the transistor 03 is turned off. The superimposed DC current is immediately stopped by the off-signal of the discharge lamp 1. The afterglow when the discharge lamp 1 is turned off is prevented. |
