A backlight unit includes a light source part having red, green and blue light sources and a light source controller to generate a common control wave and to drive each of the red, green and blue light sources by use of a dimming signal from the outside and the common control wave. The light source controller may include a pulse width modulation controller. The common control wave may have a triangular shape. Each of the red, green and blue light sources is driven with the common triangular wave which is generated by a triangular wave generator. The size of the light source controller may be reduced and flickers may be substantially reduced.