| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED power supply device capable of detecting abnormalities of LED lamps connected in parallel.SOLUTION: In an LED power supply device 1, a plurality of LED lamps LAMP1 and LAMP2 each comprising an LED light source D, and a current restriction circuit IC1 for restricting a current flowing in the LED light source D to a predetermined value or less, are connected in parallel, and a DC voltage is applied. The LED power supply device 1 comprises: a resistor R3 detecting an LED lamp current Io flowing in the plurality of LED lamps LAMP1 and LAMP2 as a whole; an AC-DC converter 2, a comparator CP2, and a variable voltage Vr2 for constant current control of the LED lamp current Io; a second voltage detection circuit 4 for detecting an output voltage Vo applied to the LED lamps LAMP1 and LAMP2; and a selection circuit 5 for selecting a current value of the LED lamp current to which the constant current control is performed, on the basis of the output voltage Vo detected by the second voltage detection circuit 4. |
