A backlight unit includes a power converter which generates a light source power voltage at a first node in response to a voltage control signal, at least one light emitting diode string which is connected between the first node and a second node and receives the light source power voltage through the first node, and a controller connected to the second node where the controller detects current of a detection node varying based on a duty ratio of the power control signal, and controls current flowing through the second node when the detected current is greater than a reference value.