DISCHARGE LAMP LIGHTING DEVICE AND LIGHTING FIXTURE

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device and a lighting fixture capable of lighting a plurality of discharge lamps with nearly the same rated lamp current and different rated power outputs, and yet, capable of preventing fading out of a lamp at light control, and carrying out filament preheating at an adequate current at all times. SOLUTION: To an output part of an inverter circuit 4, a resonant circuit having a series circuit of a ballast choke 8 and a resonant capacitor 9 is connected, and also, discharge lamps 13, 14 with nearly the same rated lamp current and different rated power outputs are connected commonly through the ballast choke, and through a series circuit of windings 10a, 10b of a balancer transformer 10 and capacitors for direct current cut 11, 12, respectively. A total volume of the lamp currents is detected by a lamp current detecting circuit 15, and a control circuit 7 controls an operating frequency of the inverter circuit so that the total lamp current volume to be constant, and performs light control of each discharge lamp by varying total lamp current volumes based on light control signals. Secondary-side windings 17b1, 17b2, 17b3 of a transformer 17 for preheating of a filament connected to the output part of the inverter circuit are connected to the filament of each discharge lamp. COPYRIGHT: (C)2007,JPO&INPIT