Research And Design Of TFT-LCD Controller

Flat panel display technology is more and more widely used in daily life. With the advantages of large capacity, high definition and ture color etc. TFT-LCD is going main trend of today's display area. As a key component in display system, the TFT-LCD controller IC is responsible for decoding the instruction which is from the external MCU, changing the information into the display data and LCD scan timing, and sending these signals to the TFT-LCD.A generic small and medium size text/graphic mixed display TFT-LCD controller IC is designed in this paper, which is composed of control unit, interface unit, data cache unit and function management unit. Firstly, the specification of the chip is analyzed, the whole framework of the chip is built and the application of the chip is given. Then, each module of the chip is designed with "top-down" approach, and it is synthesised using Synopsys Design Compiler and SMIC 0.35μm 3.3V CMOS technology library. After that, system verifications are done based on the design specification. Finally, layout is designed using Cadence SOC Encounter and it passes DRC, LVS and other tests before tape out. It should be noted that data cache unit and function management unit are implemented by third-party companies verified silicon IP cores.Each module of TFT-LCD controller IC is designed in the hardware way, and the instruction set based on RS-232 is hardened in the chip. Due to the drawing algorithm optimized, parallel architecture and multi-stage pipeline flow designed in the geometric mapping control module, the drawing efficiency has increased more than three times. The text display control module has improved FLASH address decoding efficiency and text display speed, since multi-stage decoding structure and data cache technology. The sysytem verification results show that the TFT-LCD controller IC meets the requirements of 256 color,4k color and 65K color TFT-LCD, the maximum resolution is up to 800×600 pixels, the refresh frequency is greater than 60Hz, and it supports 32 stage programmable PWM for back-light adjusting. Specifically, the TFT-LCD controller IC provides an easy way to draw the programmable geometric shape by hardware, such as point, line, circle, rectangle etc. It supports four kinds of scroll mode, including ring shift left, ring shift right, shift left clean right and shift right clean left. It supports picture display and copy. Besides, it supports font size, font color, font backgroud color, and the distance between the ranks edit. In addition, it supports ASCII and Chinese characters mixed display. Therefore, the TFT-LCD controller IC meets the requirements of the design sepcification.