| 摘要 |
PURPOSE:To provide an electric discharge lamp lighting device by which an electric discharge lamp is hard to flash momentarily or a main circuit is hard to be put in an abnormal mode. CONSTITUTION:When commercial AC electric power supply E is closed, since voltage of a capacitor C2 is impressed upon a control part 25, control is carried out as usual, and a fluorescent lamp FL is lighted by an inverter circuit 22. When the commercial AC electric power supply E is turned off, voltage of a smoothing capacitor C1 is reduced according to a time constant, and voltage of a smoothing capacitor C2 is reduced gradually. According to stopping of the commercial AC electric power supply E, voltage of a reversal input terminal of an operation amplifier OP drops, and voltage of a non-reversal input terminal of the operation amplifier OP is reduced. After the commercial AC electric power supply E is cut, the operation amplifier OP becomes H level output, and a transistor Q1 is put in an ON condition, and electric charge of the smoothing capacitor C2 is discharged by a resistor R1 and a loop of the transistor Q1. Since the electric power supply of the control part 25 is cut off, output of the inverter circuit 22 is cut off. |
