POWER SUPPLY DEVICE FOR LED PARALLEL DRIVING

摘要

PROBLEM TO BE SOLVED: To provide a power supply device capable of driving two or more parallelly connected LEDs in one output and continuously lighting remaining LEDs with the same brightness even if a trouble occurs in one LED.

SOLUTION: A power supply device for LED parallel driving comprises: a regulator part 10 which stabilizes a DC input and outputs a DC and a feedback circuit 14 which creates a feedback signal for stabilization control based on a load current detection resistor provided in series in an LED which serves as a load and a drop voltage by the load current detection resistor and inputs the created signal to a feedback terminal of the regulator part. The power supply device for LED drives an LED with the DC output stabilized by the regulator part. A plurality of LEDs are provided in parallel for one DC output of the regulator part. A load current detection resistor R1 is connected between the cathode side of an LED 12a and a GND. A load current detection resistor R2 is connected between the cathode side of an LED 12b and the GND. The feedback circuit is provided with a diode OR circuit 16 connected to each load current detection resistor and creates a feedback signal based on a terminal voltage of a load current detection resistor having the largest voltage drop.

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