| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high-speed pulse-width modulation circuit, and to provide a rare gas discharge lamp lighting device using it. <P>SOLUTION: An oscillation circuit oscillates at a predetermined oscillation frequency determined by a capacitor CT and a resistor RT. The duty ratio of the oscillation circuit is controlled to obtain pulse-width-modulated output. Both the ends of the resistor RT which determines the oscillation frequency of the pulse-width modulation circuit 1 are short-circuited by a transistor TR2 to vary the value of the resistor RT. In the pulse-width modulation circuit, the resistor RT is short-circuited to shorten the time required for charging the capacitor CT. Thus, a higher-speed pulse-width modulation circuit 1 is obtained as compared with cases where the capacitor CT is short-circuited to shorten the discharging time. <P>COPYRIGHT: (C)2004,JPO |
