一种驱动MOS管工作在饱和区的硅基OLED微显示像素电路  

Pixel circuit for OLED-on-silicon microdisplay using a driving MOS transistor operated in saturation region

作　　者：戴爽[1] 谢杉杉[1] 陈鑫[1] 杨春城[1] 张健[1] 赵毅[1] 李传南[1] 

机构地区：[1]吉林大学电子科学与工程学院集成光电子学国家重点联合实验室吉林大学实验区,吉林长春130012

出　　处：《液晶与显示》2016年第1期97-103,共7页Chinese Journal of Liquid Crystals and Displays

基　　金：国家自然科学基金(No.61177025;No.61275024);国家重点基础研究发展计划项目(No.2010CB327701);吉林省科技发展计划项目(No.20130102009JC)~~

摘　　要：硅基OLED微显示中为了在极小的像素面积内实现微小的OLED工作电流,其像素驱动电路的驱动MOS管一般工作在亚阈值区,存在OLED电流对驱动MOS管的阈值电压和栅源电压失配敏感、外围电路复杂等问题,如果驱动MOS管工作在饱和区则可避免这些问题,但为了获得微小的驱动电流,必须采用尺寸大的倒比MOS管,这又与极小的像素面积冲突。本文提出了一种采用脉宽调制(PWM)技术、驱动MOS管工作在饱和区的OLED微显示像素驱动电路,PWM信号减少了一帧内OLED的实际工作时间,OLED的脉冲电流变大,使驱动MOS倒比管的尺寸减小;由于PWM信号占空比小,同时实现了OLED微小的平均像素驱动电流和亮度。结果表明PWM信号占空比为3%时,实现的OLED驱动电流和像素亮度范围分别为27pA^2.635nA、2.19~225.1cd/m^2,同时采用双像素版图共用技术,在15μm×15μm的像素面积内实现了像素驱动电路的版图设计。Due to the tiny pixel area of OLED-on-silicon mtcrocltsptay and the weak driving MOS transistor operated in sub-threshold region is generally applied in the pixel driving circuit of OLED mierodisplay. Unfortunately the sub-threshold current of MOS transistor is sensitive to the mismatch of threshold voltage and gate-source voltage and its peripheral circuit becomes complex, but a driving MOS transistor operated in saturation region instead of in sub-threshold region can avoid these problems. In this paper a pixel driving circuit for OLED microdisplay using the pulse width modulation （PWM） technique is proposed, in which the driving MOS transistor operates in saturation region, and the small average driving current and brightness are realized by shortening the operating time of OLED during a frame period. In the meanwhile the OLED pulse current is enlarged and the area of the MOS transistor operated in saturation region is decreased. The simulation results show that the av- erage OLED current of the proposed PWM pixel driving circuit is from 27 pA to 2. 635 nA, and the bright- ness of pixel is 2. 19~225.1 cd/m2 correspondingly. The layout of the pixel driving circuit on silicon is real- ized among the pixel size of 15 μm× 15 μm using double-pixel layout sharing technique.

关 键 词：硅基OLED微显示 像素驱动电路 脉宽调制(PWM) 驱动MOS管 饱和区 

分 类 号：TN383.1[电子电信—物理电子学]