Design Of OLED Display Driver Control Circuit

With the development of science technology and the optimization of IC technology, a novel display device, Organic light-emitting Diode display(OLED) becomes outstanding in the display device area with its superior performance and has been widely used in commercial and military fields. In order to improve the refresh rate and optimize OLED display effect, we propose a display driver control system based on OLED device. There are two innovation points of this thesis:(1) Nonlinear correction based on human visual model is introduced in the system. Combined with the influence of environment light and human feelings, the gamma correction coefficient is 2.2. Nonlinear correction is realized in digital module and effectively reduce the difficulty of analog module. During the transition of PWM duty ratio signal, the grayscale data of AD sampling is transformed as A’=λA2.2 and corrected data is got by researching the lookup table.(2) A novel average separated PWM algorithm is presented to achieve 65536 grayscale display on OLED display. The PWM waveform is averagely divided into several sections in a whole PWM period and the gray data is separated into three parts: the highest significant grayscale data, the secondary significant grayscale data and low significant grayscale data. The results of simulation analysis show that compared with conventional PWM dimming, this progressive algorithm could enhance the visual refresh rate and diminish the influence of high significant bit on gray uniformity. Furthermore, compared with common frequency multiplication PWM algorithm, the new algorithm improves the poor grayscale display performance that caused by frequent changing of low bit switches.The simulation results show that this OLED display driver control system not only can increase the refresh rate but also improve fidelity and layering of the image.