Abarca Accel, Theuwissen Albert
Electronic Instrumentation Lab., Microelectronics, EWI, Delft University of Technology, 2628 CD Delft, The Netherlands.
Harvest Imaging, 3960 Bree, Belgium.
Micromachines (Basel). 2020 Jul 8;11(7):665. doi: 10.3390/mi11070665.
This article presents in-pixel (of a CMOS image sensor (CIS)) temperature sensors with improved accuracy in the spatial and the temporal domain. The goal of the temperature sensors is to be used to compensate for dark (current) fixed pattern noise (FPN) during the exposure of the CIS. The temperature sensors are based on substrate parasitic bipolar junction transistor (BJT) and on the nMOS source follower of the pixel. The accuracy of these temperature sensors has been improved in the analog domain by using dynamic element matching (DEM), a temperature independent bias current based on a bandgap reference (BGR) with a temperature independent resistor, correlated double sampling (CDS), and a full BGR bias of the gain amplifier. The accuracy of the bipolar based temperature sensor has been improved to a level of ±0.25 °C, a 3σ variation of ±0.7 °C in the spatial domain, and a 3σ variation of ±1 °C in the temporal domain. In the case of the nMOS based temperature sensor, an accuracy of ±0.45 °C, 3σ variation of ±0.95 °C in the spatial domain, and ±1.4 °C in the temporal domain have been acquired. The temperature range is between -40 °C and 100 °C.
本文介绍了一种用于互补金属氧化物半导体图像传感器（CMOS图像传感器，CIS）像素内的温度传感器，其在空间和时间域的精度都有所提高。这些温度传感器的目标是用于在CIS曝光期间补偿暗（电流）固定模式噪声（FPN）。温度传感器基于衬底寄生双极结型晶体管（BJT）和像素的nMOS源极跟随器。通过使用动态元件匹配（DEM）、基于带隙基准（BGR）和温度无关电阻的温度无关偏置电流、相关双采样（CDS）以及增益放大器的全BGR偏置，这些温度传感器在模拟域的精度得到了提高。基于双极型的温度传感器的精度已提高到±0.25°C的水平，在空间域的3σ变化为±0.7°C，在时间域的3σ变化为±1°C。对于基于nMOS的温度传感器，已获得±0.45°C的精度，在空间域的3σ变化为±0.95°C，在时间域的3σ变化为±1.4°C。温度范围在-40°C至100°C之间。
