| 摘要 |
PURPOSE: To simplify the circuit structure of a lighting apparatus for a discharge lamp and make the lighting apparatus have high efficiency. CONSTITUTION: When MOS-FETs 4, 5 are turned on and off by applying d.c. voltage of a d.c. electric power source 1 to a d.c.-a.c. transformation circuit 2, a capacitor 7 and reactors 12, 13 are resonated and resonance voltage with sinusoidal waveform is generated between the both ends of the capacitor 7. Consequently, a.c. voltage to which the resonance voltage is added is generated between both ends of a primary coild 6a, 6b of a transformer 6. As a result, the voltage of the both ends of the primary coil 6a, 6b alters by controlling the switching frequency of the MOS-FETs 4, 5 of the d.c.-a.c. transforming circuit 2 by a frequency controlling means 14, so that the brightness of a discharge lamp 3 can be altered by controlling the voltage to be applied the discharge lamp 3. A d.c. electric source apparatus having variable output is thus made unnecessary, so that the circuit structure of a lighting apparatus for a discharge lamp can be simplified and the apparatus is made to be highly efficient. |
