WORKSHOP PAPER
A CMOS Image Sensor with In-Pixel Temperature Sensors for Dark Signal Non-Uniformity Compensation
Abstract
This paper presents a CMOS image sensor with in-pixel temperature sensors for dark signal non-uniformity (DSNU) compensation between -20 ⁰C and 80 ⁰C. Two types of in-pixel temperature sensors, based on a BJT or on the in-pixel source follower (SF) itself, are implemented, measured, and compared. Both temperature sensors achieve inaccuracies less than ±0.3 ⁰C, when measured on 3 test chips. Dark current measured on neighboring image pixels of the two types of temperature sensors shows that the SF based one incurs no penalty to the image sensor array, while the BJT based alternative can introduce 100 times more dark current to its surrounding pixels. Using the temperature information provided by the in-pixel temperature sensors, the average dark current can be predicted and compensated by at least 70% on 3 measured chips.Keywords
CMOS Image Sensor, In-Pixel Temperature Sensors, Dark Signal Non-Uniformity Compensation,References
1) S. Xie, A. Abarca, J. Markenhof, X. Ge, and A. Theuwissen, "Analysis and calibration of process variations for an array of temperature sensors", 2017 IEEE SENSORS, 2017. https://doi.org/10.1109/icsens.2017.8233959
2) A. Abarca, S. Xie, J. Markenhof, and A. Theuwissen, "Integration of 555 temperature sensors into a 64 × 192 CMOS image sensor", Sensors and Actuators A: Physical, vol. 282, 2018. https://doi.org/10.1016/j.sna.2018.09.029
3) J. M. Margarit, G. Vergara, V. Villamayor, et.al, "A 2 kfps Sub-µW/Pix Uncooled-PbSe Digital Imager With 10 Bit DR Adjustment and FPN Correction for High-Speed and Low-Cost MWIR Applications", IEEE Journal of Solid-State Circuits, vol. 50, no. 10, 2015. https://doi.org/10.1109/jssc.2015.2464672
4) K. Seo, S. Lee, P. Ahn, D. Kim, and K. Cho, "A Study on Photon Effect to Image Plane", 2017 International Image Sensor Workshop, 2017. https://doi.org/10.60928/veyx-zck0
5) Jean-Marc Belloir, et.al, "Dark Current Blooming in Pinned Photodiode CMOS Image Sensors", IEEE Journal of Solid-State Circuits, vol. 50, no. 10, 2015
6) W. Song, J. Lee, N. Cho, and J. Burm, "An Ultralow Power Time-Domain Temperature Sensor With Time-Domain Delta–Sigma TDC", IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 64, no. 10, 2017. https://doi.org/10.1109/tcsii.2015.2503717
7) K. Makinwa, "Smart Temperature Sensor Survey", available online at: https://ei.tudelft.nl/smart_temperature/