用液晶驱动芯片驱动有机发光显示屏的设计

Design of Driving OLED by Liquid Crystal Driving Chip

应用TFT液晶驱动芯片设计了一个TFT有机发光显示屏用的驱动电路。目前有机发光显示屏(OLED)是平板显示领域的研究热点,在研制长寿命、高稳定的器件方面取得了一定的进展,但与之配套的驱动电路还不是很成熟,而且专用芯片又价格昂贵。液晶显示器件的配套驱动芯片功能比较完善,且价格低廉,所以应用TFT液晶驱动芯片设计了TFT有机发光显示屏用的驱动电路很有实际意义。比较了TFT LCD与TFT OLED驱动原理的异同点,从原理上探讨了将TFT LCD用的驱动芯片加以改造,使其可用于驱动TFT OLED,并采用三星公司的TFT液晶驱动芯片S6C0655和S6C0671设计了一个驱动64×3×80的全彩色OLED显示屏的驱动电路。

OLED (organic light-emitting diode) is an important member of flat panel displays (FPD). Due to its many merits such as high luminance, low drive voltage, high response speed and variety of emission colors, etc., OLED attracts worldwide attention in the fields of science and industry. At the present time progress in making long life and high stability has been made, but drive circuit for OLED is not very perfect, and chips for OLED are very simple, and the functions of chips are very simple. Meanwhile the functions of drive circuit chips for LCD are very perfect and the price is very cheap, so we determine to design a drive circuit for TFT-OLED with TFT-LCD drive chips.Firstly, the article compares the driving principle of TFT-LCD and the one of TFT-OLED,and finds that two driving principles are very resemble, so it is possible changing the drive chip of TFT-LCD and making it drive TFT-OLED. Then we choose two types of TFT-LCD chips fabricated by Samsung. One is the 120/128 channels TFT-LCD gate driver S6C0655, the other is the 6 bit 480 channels source driver S6C0671. After analyzing the chips, we find that the driving timing, display data, output driving voltage and currency of the chips meet the need of our color TFT-OLED completely. The voltage on liquid crystal pixel is alternating voltage, but the voltage on OLED pixel is direct voltage, so we adjust the input on POL pin, let it maintain low voltage always. We choose 80 channels of S6C0655 and 240 channels of S6C0671 because the standard of our color display is 64×3×80. At last, we design a circuit with a piece of MCU, a piece of S6C0655, a piece of S6C0671, a piece of ROM and some periphery circuits. ROM, S6C0655 and S6C0671 are controlled by MCU. Display data are stored in ROM. When the circuit is working, MCU gets the data from ROM and transfers them to S6C0671 and transfers shift pulse to S6C0655 synchronously.