| 摘要 |
A discharge lamp (6) energizing power supply device is operable to reduce an electric power loss in a wide range of commercial power supply voltages employed in various parts of the world, and can stably perform its functions without causing a functional shutdown of a boosting circuit (11) due to an increase in the power supply voltage and a functional shutdown of a voltage lowering circuit due to a characteristic deterioration of a discharge lamp (6). The discharge lamp energizing power supply device has a full-wave rectifier circuit (2) for rectifying an AC voltage (1) obtained from a commercial AC power supply system into a full-wave rectified waveform (E O ), a booster circuit (11) for boosting the voltage of the full-wave rectified waveform (E O ), a boosted-voltage changing circuit (12) for changing the boosted voltage output from the booster circuit (11), a voltage lowering circuit (14) for lowering an output voltage from the boosted-voltage changing circuit (12) and outputting an activating output voltage (V O ) for activating a discharge lamp (6) and an energizing output voltage (V L ) for keeping the discharge lamp (6) energized, and a control device (7) for controlling a boosted voltage in the boosted-voltage changing circuit (12) within a predetermined range based on the voltage of the full-wave rectified waveform (E O ) when the voltage lowering circuit (14) outputs the energizing output voltage (V L ).
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