| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device that can output a stable control power supply voltage without reducing an efficiency of a circuit even when used for a device having a wide range of an input voltage.SOLUTION: In a power supply device 11, a transformer 22 comprises a second coil N2 that is a flyback coil, and third coils N3a and N3b that are forward coils each provided with a tap. A second DC/DC converter 17 supplies a power obtained by a voltage outputted from the second coil N2 and then rectified and smoothed, to a light source 16. A voltage detection circuit 27 detects a voltage outputted from the third coils N3a and N3b. A control circuit 15 determines a type of a power supply AC on the basis of the voltage detected by the voltage detection circuit 27, selects a tap depending on the determination result, and then, monitors the voltage outputted from the third coils N3a and N3b, and controls power supply from the second DC/DC converter 17 to the light source 16 on the basis of the monitored voltage. |
