| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which can maintain no-load voltage constant at the time of starting even if the length of a lamp line is changed. SOLUTION: This device is provided with a DC power supply part 1, a series resonant circuit consisting of serially-connected transistors 2, 3, a choke coil 4 which is connected in parallel to the transistor 3, and a capacitor 5, a capacitor 6 for power source, a transformer 7 whose primary winding is connected in parallel to the capacitor 5, and a frequency modulation control circuit 8 which has a resistor 9 and a capacitor 10, and turns on/off the transistors 2, 3 alternately, and a discharge lamp is connected to the secondary winding of the transformer 7 through a lamp line. This device is constituted by forming the third winding at the transformer 7, rectifying and smoothing the output of the winding with a diode 11 and a capacitor 12 to apply it to a trimmer resistor 13, connecting the output of the trimmer resistor with the base of a transistor 16 through a resistor 14 and a constant voltage diode 15, connecting a collector of the transistor with the capacitor 10 of the frequency modulation control circuit, and connecting an emitter with the power source through a resistor 17. |
