| 摘要 |
PURPOSE:To reduce the characteristic dispersion of a discharge lamp against the power source voltage fluctuation and prevent the short life of the lamp by operating a closed circuit on/off-controlling a transistor with the voltage proportional to the lamp voltage. CONSTITUTION:A drive circuit 17 on/off-controlling a transistor 11 is operated by the voltage proportional to the lamp voltage, when the power source voltage is increased at the time of lamp lighting, the lamp current is increased, the voltage of a discharge lamp 10 is decreased, and the voltage generated across the secondary winding 50b of an inductance 50 is decreased. The base current of the transistor is decreased, the on time is shortened. The input power, lamp current and lamp power are decreased, and the characteristic dispersion of the discharge lamp 10 can be decreased. The input power and the characteristic dispersion of the discharge lamp against the power source voltage fluctuation can be decreased, the short life of the lamp can be prevented, a discharge lamp lighting device can be realized with components having a small rating. |
