薄膜晶体管液晶显示器的点对点传输协议

Point-to-point interface protocol for thin film transistor-liquid crystal display

随着TFT-LCD在尺寸、分辨率及刷新率方向的飞速发展,优质的显示品味对时序控制器(T-CON)和特定源极驱动芯片(SD)之间的传统接口传输协议速率提出了挑战,因此成为TFT-LCD发展的关键。为了实现数据信号的高速传输,本文研究并提出了一种新型高速点对点接口传输协议CSPI(China Standard Point-to-Point Interface)。CSPI通过嵌入式的CDR(Clock Data Recovery)机制实现T-CON和SD之间时钟校准,CDR校准完成后,指令信号LS输出高电平并反馈发送端T-CON,通知T-CON可以传输下一阶段有效数据,同时,CSPI技术特定封装包对位数据嵌入传输数据线中。数据传输采用特有的8位/9位编码和扰码技术以实现数据快速而不失精准的传输。相对于传统mini-LVDS接口协议,CSPI技术的传输速率可以提升至3Gb/s,有效减少传输线数量,同时大幅提升信号传输质量。此外,CSPI时钟信号内置,可以有效降低EMI。基于1 383mm(55in)超高清液晶显示屏的实验结果表明,眼图的最小幅度和宽度分别约为312mV和548ps。可以满足系统对传输信号稳定性,可靠性和抗干扰能力的要求,同时减少印刷电路板(PCB)布局面积,有利于降低成本。

With the development of the thin film transistor-liquid crystal display(TFT-LCD)on size and resolution,the traditional interface transmission protocol between the timing controller(T-CON)and the specific source driver(SD)is no longer applicable and it becomes a critical challenge for the conventional interface protocol.In order to improve the high-speed transmission of data signals,this paper proposes and studies a novel high-speed point-to-point interface transmission protocol in the display panel field,named China Standard Point-to-Point Interface(CSPI).The CSPI protocol implements clock calibration between T-CON and SD through embedded Clock Data Recovery(CDR)mechanism.After CDR calibration completes,the instruction signal Link Status(LS)outputs high level to T-CON,informing the sender that the next stage of valid data can be transmitted.The CSPI technology specific packet alignment data is also embedded in the transmission data line.The particular 8 B/9 Bcoding technique is adopted for data transmission as well as a scrambling scheme.Compared with the traditional mini-LVDS interface protocol,CSPI technology can improve transmission rate to 3 Gb/s,and has outstanding features of high data rate and less signal lines which is particularly well-suited for high-end TFT-LCD panel.Moreover,CSPI technology built-in clock signal,which can effectively reduce EMI.Experimental results based on the 55"Ultra-High Definition(UHD)LCD panel indicate that the minimum amplitude and width of the eye diagram are approximately 312 mV and 548 ps,respectively.It can satisfy the system requirements of the stability,reliability and anti-interference ability of the transmitted signal as well as reduce Printed Circuit Board(PCB)layout area.