There is provided a backlight unit including a backlight configured to generate light, and a backlight driving circuit configured to drive the backlight in a dimming mode on a basis of a dimming signal, the backlight driving circuit including a first comparator configured to detect a frequency of the dimming signal and to compare the frequency of the dimming signal with a reference frequency to determine a compared result, and a driver configured to selectively drive the backlight, based on the compared result, in an analog dimming mode in which a driving current of the backlight is controlled, or a mixed dimming mode by mixing the analog dimming mode and a digital dimming mode in which an on state and an off state of the backlight is controlled.