| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device that reliably turns off a semiconductor light emitting device in a power supplied state, and to provide a luminaire. SOLUTION: In the power supply device, energy discharged through the secondary winding 16b of a switching transformer 16 by turning on/off of a switching transistor 17 is converted into DC output with rectifying/smoothing circuits 23, thereby turning on light emitting diodes 24 to 27 with the converted DC output. When the light emitting diodes 24 to 27 are turned on, the power supply device controls the currents flowing in the light emitting diodes 24 to 27 to be constant depending on the signal detected with a current detecting unit 29. When the light emitting diodes 24 to 27 are turned off, the power supply device controls the voltage applied to the light emitting diodes 24 to 27 to be constant voltage which is lower than the lighting start voltage, depending on comparison results between the voltage value which is lower than the lighting start voltage of the light emitting diodes 24 to 27 set in advance as a reference value and the signal detected with a voltage detecting unit 28. COPYRIGHT: (C)2009,JPO&INPIT
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