| 摘要 |
In a lighting apparatus for a discharge lamp, a mask signal against a re-arc voltage is correctly generated to detect a lamp voltage accurately in view of a support to high frequency lighting such that the detection of the lamp voltage is not affected by the re-arc voltage. The lighting apparatus for the discharge lamp comprises a DC-AC converter for receiving an input voltage from a DC power supply to convert the input voltage to an AC voltage; detecting means for detecting a lamp voltage associated with a discharge lamp or a lamp voltage and a lamp current; and a signal generator circuit for generating a mask signal for excluding a re-arc voltage, which occurs at the time the polarity is inverted, from items to be detected, in the event of a detection of the lamp voltage. The signal generator circuit detects the lamp voltage or lamp current or a voltage at an output stage of the DC-AC converter to correctly capture a polarity inversion timing to generate a mask signal against the re-arc voltage. A timing shift of the mask signal can be limited within an allowable range even if the discharge lamp is lit at a high frequency.
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