Liquid crystal display and scanning back light driving method thereof

A liquid crystal display, comprising:

• a liquid crystal display panel configured to display modulated data based on a frame frequency;
• light sources configured to generate light to be irradiated into the liquid crystal display panel;
• a scanning backlight controller configured to calculate a turn-on duty ratio of a pulse width modulation (PWM) signal for controlling turn-on and turn-off operations of the light sources;
• and
• a light source driver configured to:
• compare the calculated turn-on duty ratio of the PWM signal with a critical value;
• differently process the PWM signal according to a result of the comparing such that a frequency of the PWM signal is synchronized with the frame frequency;
• the turn-on duty ratio of the PWM signal is changed to a value corresponding to full operation of the PWM signal;
• an amplitude of the PWM signal is adjusted based on a changed degree of the turn-on duty ratio of the PWM signal;
• and
• subsequently sequentially drive the light sources along a data scanning direction of the liquid crystal display panel,
• wherein the scanning backlight controller comprises an input image analysis unit, a duty ratio calculation unit, and a data modulation unit,
• wherein the input image analysis unit is configured to:
• compute a cumulative distribution function of digital video data of an input image;
• calculate a frame representative value based on the cumulative distribution function, the calculation including a mean value and a mode value of the cumulative distribution function;
• determine a gain value based on the frame representative value;
• and
• supply the gain value to the duty ratio calculation unit and the data modulation unit, and
• wherein the duty ratio calculation unit is configured to calculate the PWM duty ratio based on the gain value received from the input image analysis unit.