量子图像传感器的过采样优化和读出电路设计  

Optimized Oversampling and Readout Circuit Design for Quanta Image Sensor

作　　者：赵彤 高静 徐江涛 聂凯明 Zhao Tong;Gao Jing;Xu Jiangtao;Nie Kaiming(School of Microelectronics,Tianjin University,Tianjin 300072,China;Tianjin Key Laboratory of Imaging and Sensing Microelectronic Techmology.Tianjin 300072,China)

机构地区：[1]天津大学微电子学院,天津300072 [2]天津市成像与感知微电子技术重点实验室,天津300072

出　　处：《激光与光电子学进展》2021年第24期137-145,共9页Laser & Optoelectronics Progress

基　　金：国家自然科学基金(61874096)。

摘　　要：量子图像传感器(QIS)在不同的过采样位深下信息冗余程度和动态范围(DR)不同,对于读出电路的要求也不同。研究了QIS成像过程中引入的读噪声,优化了QIS成像的数学模型。在动态范围和失调容限的约束下,得到了子像素过采样的最优位深。仿真结果表明,当QIS的成像位深为12 bit、等效满阱容量为4095 electron时,子像素过采样的最佳比特位深是3,为保证区间误码率小于千分之一,读出电路失调应低于0.22 electron。根据采样策略,设计了一种基于复用结构的flash型低噪声读出电路。相对于传统flash型模数变换器(ADC),所提ADC比较器的个数减少了4个,采样频率为10 MSa/s时,功耗降低了17.5%;采样频率为1 MSa/s时,ADC的功耗为116 nW,ADC的失调为0.196 electron。The data redundancy and dynamic range(DR) of quanta image sensor(QIS) are different under different oversampling bit-depth, and the requirements for readout circuit are also different. The reading noise introduced in the imaging process of QIS is studied, and the mathematical model of QIS imaging is optimized. Under the constraints of DR and offset tolerance, the optimal bit-depth of sub-pixel oversampling is obtained. The simulation results show that when the imaging bit-depth of the QIS is 12 bit and the equivalent full well capacity is 4095 electron, the optimal bit-depth of sub-pixel oversampling is 3. In order to ensure that the interval bit error rate is less than one thousandth, the readout circuit offset should be less than 0.22 electron. According to the sampling strategy, a flash low noise readout circuit based on multiplexing structure is designed. Compared with the traditional flash analog-to-digital converter(ADC), the number of ADC comparators is reduced by 4, and the power consumption is reduced by 17.5% when the sampling frequency is 10 MSa/s;when the sampling frequency is 1 MSa/s, the power consumption of ADC is 116 nW and the offset of ADC is 0.196 electron.

关 键 词：统计光学 光子计数 量子图像传感器 过采样策略 动态范围 低功耗 低失调 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]