| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which can surely reduce harmonics. SOLUTION: When a voltage value of a full-wave rectifier circuit 1 is a voltage value or more of a charging capacitor C4, an input current is supplied to an inverter circuit 3 from a first/second capacitor C1, C2. When the voltage value of the full-wave rectifier circuit 1 is decreased lower than the voltage value of the charging capacitor C4, an input current is supplied, substantially continuously from a vibration circuit 5. By a power voltage change and a load fluctuation or a temperature characteristic of a fluorescent lamp FL, when an output is decreased, voltage of the second capacitor C2 is generated higher than output voltage of the full-wave rectifier circuit 1. Since voltage, is not induced in a secondary winding Tr1b or a current transformer Tr1, a transistor Q2 is turned off, by a resistor R3, R4, a capacitor C8 is gradually charged, voltage is gradually applied to a gate of a field effect transistor Q3, to place gradually in an on-condition from an off-condition, a current is supplied to a resistor R5, and a soft start is performed, so as to reduce harmonic component continuously without sharply forming an input current. |
