| 摘要 |
In a discharge lamp lighting circuit 1, there are provided a DC power supply portion 4 for receiving a supply voltage from a DC power supply 2 via an overcurrent protecting means 3, a DC-AC converter portion 5 for converting an output voltage of the DC power supply portion 4 into an AC voltage to supply the AC voltage to a discharge lamp 8, a starter circuit 6 for starting the discharge lamp 8 by applying a high voltage pulse to it, and a control circuit 7 for detecting a voltage or a current for the discharge lamp 8 to control a supply power to the discharge lamp 8 or to decide whether or not a failure occurs in a lighting state of the discharge lamp 8 or in the input voltage from the DC power supply 2. Thus, a voltage obtained from a position that is located closer to the DC power supply than the overcurrent protecting means 3 or a voltage generated based on such voltage, or a voltage supplied from another system different from the DC power supply 2 or a voltage generated based on such voltage is supplied to the control circuit 7 as the power supply voltage.
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