| 摘要 |
PURPOSE:To reduce the voltage applied to a switch element and provide a device having less generated noise with a low loss by connecting a capacitor and the primary side of a transformer in series to the middle point of two switch elements connected in series to a DC power source, and connecting a discharge lamp on the secondary side of the transformer. CONSTITUTION:An oscillator 7 oscillates and outputs a square wave at a period proportional to a variable resistance 8. An inverter 6 reverses the output of the oscillator 7, and switch elements 2, 5 and 3, 4 are alternately ON/OFF. After a discharge lamp 12 is lighted at a frequency near the resonance frequency on the primary side of a transformer 10, discharge is kept with a discharge current according to the frequency. Thus, the starting voltage of the discharge lamp 12 is shared by the transformer 10 and the capacitor 9, and the withstand voltages of the elements 2-5 may be low. Thus, the loss can be reduced, the generated noise is reduced, and the light can be easily controlled only by changing the frequency. |
