| 摘要 |
PROBLEM TO BE SOLVED: To increase a lighting duration time at the time of power failure without requiring the increase of the battery capacity of a backup power supply in a power supply device for illumination to be selectively connected to a commercial power supply and a backup power supply.SOLUTION: A power supply device (10) for illumination to be selectively connected to a commercial power supply (AC) and a backup power supply (2) includes: a full wave rectifier circuit part (11) to which an input voltage is supplied; a switching power supply circuit part (12) for supplying limited currents from the output voltage of the full wave rectifier circuit part to a light source (15); an input voltage detection circuit (13) for detecting the rectification voltage of the input voltage; and a control part (14) for determining whether or not the input voltage is a voltage from the commercial power supply on the basis of the rectification voltage detected by the input voltage detection part, and for, when determining that the input voltage is not the voltage from the commercial power supply, allowing the switching power supply circuit part to output currents for dimmed lighting. |
