A backlight unit includes: a light source unit including at least one light emitting diode (“LED”) string; a driving current controller which is connected to a cathode terminal of the at least one LED string and controls a driving current which flows through the at least one LED string; a feedback unit which generates a feedback signal based on a dimming input signal and a voltage of the cathode terminal of the at least one LED string; and a direct current to direct current (“DC-DC”) converter which generates a driving voltage in response to the feedback signal and provides the driving voltage to the light source unit.