题目/Title：采用电荷复位技术的像素级ADC
                        Pixel-level A/D Conversion Using Charge Reset Technique

作者/Author：李敏增,李福乐,张春
                        Minzeng Li,Fule Li,Chun Zhang

期刊/Journal：半导体技术 Semiconductor Technology

年份/Issue Date：2014.Sept.

卷（期）及页码/Volume（No.）&pages：Vol.39, No.9, pp. 656 - 660+665

摘要/Abstract：
实现了一种可用于CMOS图像传感器,采样率为50 Hz、精度为15位的像素级模数转换器(ADC)。此ADC采用电荷复位方式补偿电荷,然后通过对电荷包计数实现模数转换。为了实现低功耗、低噪声和小面积,对电路系统、核心模块的设计以及版图布局布线进行了综合考虑和优化。该设计采用SMIC 0.18μm CMOS标准工艺,版图面积为50μm×50μm。测试结果表明:当输入电流为17.5,33.7和80 nA时,对应的输出码的均值/标准差分别为8 875/6.56,16 500/2.6,32 768/14.3。在满量
A 50 Hz analog-to-digital converter ( ADC) with the precision of 15 bit for the pixel level implementation in the CMOS image sensor was presented． The ADC adopts charge reset technique to balance the charge packet，and the analog-to-digital conversion is achieved through counting charge packets． The circuit system，the design of the core modules and layout placement are comprehensive considered and specially optimized for the low power，low noise and small area． The ADC has an area of50 μm × 50 μm in a standard 0. 18 μm CMOS process． The test results show that when the input currents are 17. 5，33. 7 and 80 nA，the mean values /the standard deviations of the output code are 8 875 /6. 56，16 500 /2. 6，32 768 /14. 3，respectively． The simulation results show that the ADC totally consumes4. 5 μW with the full scale input current of 80 nA．