| 摘要 |
PURPOSE:To drive easily a load such as a high pressure discharge lamp which needs the high voltage at the time of starting by applying the high pressure pulse voltage, the high frequency voltage having a small amplitude and the direct current voltage. CONSTITUTION:The high pressure pulse voltage VOP is generated by an igniter IG during an operating period T1a, T2b, and it is applied to the high pressure discharge lamp H to make the high pressure discharge lamp H under the glow discharge condition. Next, transistors Q1, Q2 are mutually turned on/off during the operating period T2a, T2b to generate the high frequency voltage VHF, and it is applied to the high pressure discharge lamp H. The amplitude of this high frequency voltage VHF is smaller than the amplitude of the high pressure pulse voltage VOP, but it is larger than the amplitude of the direct current voltage VDC following thereafter. Next, during the operating period T3a, the positive direct current voltage VDC is generated by turning on/off the transistor Q1 with the high frequency under the condition that the transistor Q2 is turned off, and it is applied to the high pressure discharge lamp H. A load such as a high pressure discharge lamp which needs the high voltage at the time of starting is thereby driven easily. |
