High linearity and low noise column readout chain are two key factors in CMOS image sensor.However,offset mismatch and charge sharing always exist in the conventional column wise readout implementation,even adopting t...High linearity and low noise column readout chain are two key factors in CMOS image sensor.However,offset mismatch and charge sharing always exist in the conventional column wise readout implementation,even adopting the technology of correlated double sample.A simple column readout circuit with improved offset mismatch and charge sharing for CMOS image sensor is proposed in this paper.Based on the bottom plate sampling and fixed common level method,this novel design can avoid the offset nonuniformity between the two buffers.Also,the single buffer and switched capacitor technique can effectively suppress the charge sharing caused by the varied operating point.The proposed approach is experimentally verified in a 1024×1024 prototype chip designed and fabricated in 55 nm low power CMOS process.The measurement results show that the linear range is extended by 20%,the readout noise of bright and dark fields is reduced by 40%and 30%respectively,and the improved photo response nonuniformity is up to 1.16%.Finally,a raw sample image taken by the prototype sensor shows the excellent practical performance.展开更多
列级读出电路是目前提升平面图像传感器读出效率最为明显的方式,但是对于亿级像素超大面阵规模下的大数据大负载高速读出,列级到输出级并串转换中的列级缓冲设计面临极大的挑战.本文提出一种基于双反馈环路的列级缓冲设计方法,该方法通...列级读出电路是目前提升平面图像传感器读出效率最为明显的方式,但是对于亿级像素超大面阵规模下的大数据大负载高速读出,列级到输出级并串转换中的列级缓冲设计面临极大的挑战.本文提出一种基于双反馈环路的列级缓冲设计方法,该方法通过在列级缓冲的近端输出与远端输出间实现双反馈环路,有效抑制了列级总线的超大寄生参数对建立时间的影响,同时确保了低噪声高动态下的模拟信号精度.基于55 nm互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)工艺,在一款12288×12288像素规模的红外图像传感器中进行了成功的应用,结果表明:与传统列级缓冲相比,本文提出的双反馈环路列级缓冲设计方法可以将上升建立时间缩短23.4%,下降建立时间缩短21.9%,亿级高速图像传感器的帧率提升29.6%.展开更多
红外焦平面的数字读出是信息化发展的必然方向,其关键技术是数字读出电路。介绍了数字读出电路的发展现状和主要架构,重点分析了时间噪声和空间噪声的来源和影响,并给出低噪声设计指导。同时对线性度、动态范围和帧频等主要性能进行了讨...红外焦平面的数字读出是信息化发展的必然方向,其关键技术是数字读出电路。介绍了数字读出电路的发展现状和主要架构,重点分析了时间噪声和空间噪声的来源和影响,并给出低噪声设计指导。同时对线性度、动态范围和帧频等主要性能进行了讨论,设计了两款数字读出电路。采用列级ADC数字读出架构设计了640×512数字焦平面探测器读出电路,读出噪声测试结果为150μV,互连中波探测器测试NETD为13 m K。基于数字像元读出架构设计了384×288数字焦平面探测器读出电路,互连长波探测器测试NETD小于4 m K,动态范围超过90 dB,帧频达到1000 Hz。所设计的两款读出电路有效提升了红外焦平面的灵敏度、动态范围和帧频等性能,表明数字读出电路技术对红外探测器性能的提升具有重要作用。展开更多
基金supported by Shaanxi Education Department (No. 19JC029)
文摘High linearity and low noise column readout chain are two key factors in CMOS image sensor.However,offset mismatch and charge sharing always exist in the conventional column wise readout implementation,even adopting the technology of correlated double sample.A simple column readout circuit with improved offset mismatch and charge sharing for CMOS image sensor is proposed in this paper.Based on the bottom plate sampling and fixed common level method,this novel design can avoid the offset nonuniformity between the two buffers.Also,the single buffer and switched capacitor technique can effectively suppress the charge sharing caused by the varied operating point.The proposed approach is experimentally verified in a 1024×1024 prototype chip designed and fabricated in 55 nm low power CMOS process.The measurement results show that the linear range is extended by 20%,the readout noise of bright and dark fields is reduced by 40%and 30%respectively,and the improved photo response nonuniformity is up to 1.16%.Finally,a raw sample image taken by the prototype sensor shows the excellent practical performance.
文摘列级读出电路是目前提升平面图像传感器读出效率最为明显的方式,但是对于亿级像素超大面阵规模下的大数据大负载高速读出,列级到输出级并串转换中的列级缓冲设计面临极大的挑战.本文提出一种基于双反馈环路的列级缓冲设计方法,该方法通过在列级缓冲的近端输出与远端输出间实现双反馈环路,有效抑制了列级总线的超大寄生参数对建立时间的影响,同时确保了低噪声高动态下的模拟信号精度.基于55 nm互补金属氧化物半导体(Complementary Metal Oxide Semiconductor,CMOS)工艺,在一款12288×12288像素规模的红外图像传感器中进行了成功的应用,结果表明:与传统列级缓冲相比,本文提出的双反馈环路列级缓冲设计方法可以将上升建立时间缩短23.4%,下降建立时间缩短21.9%,亿级高速图像传感器的帧率提升29.6%.
文摘红外焦平面的数字读出是信息化发展的必然方向,其关键技术是数字读出电路。介绍了数字读出电路的发展现状和主要架构,重点分析了时间噪声和空间噪声的来源和影响,并给出低噪声设计指导。同时对线性度、动态范围和帧频等主要性能进行了讨论,设计了两款数字读出电路。采用列级ADC数字读出架构设计了640×512数字焦平面探测器读出电路,读出噪声测试结果为150μV,互连中波探测器测试NETD为13 m K。基于数字像元读出架构设计了384×288数字焦平面探测器读出电路,互连长波探测器测试NETD小于4 m K,动态范围超过90 dB,帧频达到1000 Hz。所设计的两款读出电路有效提升了红外焦平面的灵敏度、动态范围和帧频等性能,表明数字读出电路技术对红外探测器性能的提升具有重要作用。
