| 摘要 |
A discharge lamp lighting apparatus has a switch circuit to convert a DC voltage into an AC voltage, a transformer, a discharge lamp, an error amplifier of a reference voltage and a voltage representative of a lamp current, a control circuit generating a PWM control signal, and a soft start circuit to carry out, at the start of a lighting operation, a soft start operation that gradually extends ON intervals of the PWM control signal to gradually increase the lamp current upto a target lamp current. The soft start circuit carries out the soft start operation in such a way that an increment in ON intervals of the PWM control signal in a period from when the discharge lamp lights to when the target lamp current is attained is smaller than that in a period from when the lighting operation starts to when the discharge lamp lights.
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