| 摘要 |
PROBLEM TO BE SOLVED: To increase a filament preheating current upon preheating a fluorescent lamp, and reduce filament loss during a lighting time of the fluorescent lamp. SOLUTION: This circuit is equipped with an inverter circuit 3 to convert a direct current to a high frequency current, a chole coil L1 which has secondary windings L1-2, L1-3 where one end is connected to an inverter circuit 3, and a fluorescent lamp LA having a filament is connected to the other end, as well as a coupling capacitor C3, a load circuit 4 having a capacitor C2 connected in parallel with the fluorescent lamp LA, and preheating circuits 5a, 5b to which power supply is supplied from the secondary windings L1-2, L1-3, and which forms a serial resonance circuit of preheating inductors L2a, L2b, preheating capacitors C4a, C4b, and the filament, and is capable of setting the filament preheating current upon preheating the fluorescent lamp LA to a current value necessary for preheating. By suppressing the filament preheating current when the fluorescent lamp LA is lighted, the filament loss of the fluorescent lamp LA can be reduced. COPYRIGHT: (C)2010,JPO&INPIT |
