A backlight unit includes a power supply converter including a primary winding connected to an input power supply voltage, and a secondary winding which is connected to an output node and outputs a light emitting diode drive voltage to the output node in response to a mode signal and a switching control signal; and a light emitting diode string connected to the output node of the power supply converter, where the power supply converter serially connects a boosting winding to the secondary winding and the output node and when the mode signal represents a three dimensional image display mode, and outputs a boosted light emitting diode drive voltage to the output node through the boosting winding.