Device and method for controlling brightness of organic light emitting diode display

A brightness control device in an OLED display device comprising:

• a computer system having either a PWM controller for converting and forwarding external brightness control information into a PWM (Pulse Width Modulation) signal and forwarding the PWM signal or a master for forwarding the brightness control data by using a data communication protocol;
• a selector for selecting either the PWM signal from the PWM controller or the brightness control data from the master;
• a normalizer for normalizing the PWM signal or the brightness control data from the selector into an external brightness adjusting gain and a preset optical compensation parameter into a optical compensation gain according to an optical characteristic of a picture display unit;
• a peak brightness value detector for analyzing a video data from the computer system to detect a peak brightness value;
• a first multiplier for multiplying the peak brightness value by the external brightness adjusting gain to produce a final peak brightness value;
• a maximum gamma voltage adjuster for adjusting R/G/B maximum gamma voltage values according to the final peak brightness value for the first time;
• a second multiplier for multiplying the R/G/B maximum gamma voltage values, adjusted by the maximum gamma voltage adjuster, by the external brightness adjusting gain to adjust the R/G/B maximum gamma voltage values for the second time;
• and
• a reference gamma voltage generator for generating R/G/B reference gamma voltage sets by using the R/G/B maximum gamma voltage values from the second multiplier.