| 摘要 |
PURPOSE: An LED driving device is provided to stably control a constant current of an LED string without a driver IC. CONSTITUTION: A detection unit(210a-210n) detects a voltage outputted from a plurality of LED strings. A switching unit is turned on or off according to a voltage difference between a voltage of a base terminal and a voltage detected by the detection unit. A regulator unit controls a constant current of the LED string by controlling a base current flowing in the base terminal of the switching unit. A power source unit(230a-230n) applies a preset voltage. A voltage drop unit(240a-240n) is connected between the power source unit and the control switching unit and drops the voltage of the power source unit. The base terminal of the switching unit is connected to a common contact point of the voltage drop unit and the control switching unit.
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