<p>PURPOSE: An LED driving device is provided to stabilize a driving current supplied to an LED by applying an output voltage to the LED when controlling the dimming of the LED. CONSTITUTION: A rectifier(110) rectifies power outputted from an AC power source. A transformation circuit(120) changes the size ofthe voltage outputted from the rectifier. A power factor correction circuit(130) corrects the power factor of the power source outputted from the AC power source. A smoothing circuit(140) smooths the voltage outputted from the transformation circuit. A constant current driving circuit(150) constantly controls the driving current of an LED module. A dimming control circuit controls the dimming by controlling the current flow of the LED module. A diode photocoupler applies the feedback voltage to the power factor correction circuit. The diode photocoupler applies the feedback voltage to the power correction circuit. A sample and hold circuit is driven and controlled by the dimming control circuit.</p>
