a backlight control device for controlling a driving current of an led is disclosed . by controlling current outputs from current sources of a plurality of current output units , a display will be able to generate desirable backlight . then by adjusting currents output by the plurality of current output units , brightness of a plurality of pixels can be dynamically adjusted . the brightness of pixels with higher gray levels can be increased while the brightness of pixels with lower gray levels can be decreased , thereby improving the contrast of image and saving power consumption .