| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact lighting device hard to be influenced by a floating container by detecting lighting of all of plural discharge lamps in a discharge lamp lighting device, in which each current flowing in plural discharge lamps flows in one or plural impedance devices and of which supplying voltage is controlled so as to constantly maintain the current in the impedance device. SOLUTION: When a discharge lamp 4 is lighted and tube current flows, the tube current is input to a tube current detecting unit 31, and the tube current detecting unit 31 converts the tube current to voltage with a resistor 32, and rectifies the voltage with diodes 33, 34, and filters the voltage with a capacitor 35, and supplies it to an operation signal generating unit 24. In the case where the discharge lamp 4 is lighted and a discharge lamp 18 is not lighted, the tube current detecting unit 36 does not output voltage, and the emitter voltage of a transistor 39 becomes higher than the base voltage thereof for turning-on by a pull-down resistor 40. When he discharge lamp 18 is lighted, the emitter voltage of the transistor 39 becomes lower than the base voltage thereof for turning-off, and the operation signal generating unit 24 is operated. |
