| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device which can control over-boosting of voltage of an output voltage of a voltage boosting circuit when a load circuit is not connected in the structure that a voltage boosting circuit is provided. SOLUTION: A DC power supply 1 is subjected to voltage conversion with a DC-DC converting circuit 4, while the voltage boosting circuit 7 is fed from a part of the DC-DC converting circuit 4 and thereby outputs a voltage which is higher than the output voltage of the DC-DC converting circuit 4. An output of the DC-DC converting circuit 4 is inputted to a polarity inverting circuit 5 to be converted to an AC voltage. A load circuit is an igniter 10 and a high voltage discharge lamp LP1 and when an output voltage of the voltage boosting circuit 7 exceeds the reference voltage Vr1, a fault detection circuit 12 judges the load circuit is not connected and stops operations of the DC-DC converting circuit 4 and polarity inverting circuit 6 through a control circuit 8. |
