A backlight assembly, a display device including the backlight assembly and a control method thereof are provided. The backlight assembly includes: a DC converter which converts input alternating current (AC) power into direct current (DC) power at various levels; a light source unit which has at least one point light source; and a power supply unit which receives the DC power output by the DC converter, converts the DC power into output power having a preset reference current level and supplies the output power to the light source unit.