Current Mode Image Sensor With Improved Linearity and Fixed-Pattern Noise

Current mode active pixel sensors convert light intensity into an analog output current. A current mode image sensor enables simple implementation of focal plane algebraic functions but suffers from poor linearity and large fixed-patten noise. This paper analyzes the causes of the non-linearity of a current-mode image sensor including a theoretical derivation and numerical simulation. Previously reported linearity improvement methods are reviewed, while an architecture of a current mode image sensor with a voltage feedback loop between pixel output and the current conveyor for linearity enhancement is proposed. An image sensor array of 100 × 200 current mode pixels is fabricated in a 0.5 μm 2P3M standard CMOS processing technology. Experimental results illustrate a 45% improvement of the linearity of the proposed imager. Fixed pattern noise is reduced by 57.6% for the maximum readout current, which can be further reduced by another 51.5% after gain calibration. A signal to noise ratio of 49.6 dB is achieved.

[1]  R. Steadman,et al.  A high dynamic range, high linearity CMOS current-mode image sensor for computed tomography , 2005, Proceedings of the 31st European Solid-State Circuits Conference, 2005. ESSCIRC 2005..

[2]  Chia-Chun Tsai,et al.  An embedded analog spatial filter design of the current-mode CMOS image sensor , 2004, IEEE Transactions on Consumer Electronics.

[3]  Kiyoharu Aizawa,et al.  Computational image sensor for on sensor compression , 1997 .

[4]  Chung-Yu Wu,et al.  The design of high-performance 128/spl times/128 CMOS image sensors using new current-readout techniques , 1999, ISCAS'99. Proceedings of the 1999 IEEE International Symposium on Circuits and Systems VLSI (Cat. No.99CH36349).

[5]  Pietro Fiorentin,et al.  Characterization and calibration of a CCD detector for light engineering , 2005, IEEE Transactions on Instrumentation and Measurement.

[6]  D. Wu,et al.  Current mode active pixel sensor architectures for large area digital imaging , 2008, 2008 International Conference on Microelectronics.

[7]  Mohamad Sawan,et al.  Variable resolution CMOS current mode active pixel sensor , 2000, 2000 IEEE International Symposium on Circuits and Systems. Emerging Technologies for the 21st Century. Proceedings (IEEE Cat No.00CH36353).

[8]  Amine Bermak,et al.  An ultra-low power operating technique for mega-pixels current-mediated CMOS imagers , 2004, IEEE Transactions on Consumer Electronics.

[9]  Christer Svensson,et al.  An Addressable 256 × 256 Photodiode Image Sensor Array with an 8-bit Digital Output , 1992 .

[10]  Qiyin Fang,et al.  CMOS Active-Pixel Sensor With In-Situ Memory for Ultrahigh-Speed Imaging , 2011, IEEE Sensors Journal.

[11]  Kyounghoon Yang,et al.  On-Chip FPN Calibration for a Linear-Logarithmic APS Using Two-Step Charge Transfer , 2013, IEEE Transactions on Electron Devices.

[12]  Jan Van der Spiegel,et al.  Linear Current-Mode Active Pixel Sensor , 2007, IEEE Journal of Solid-State Circuits.

[13]  Kenneth C. Smith,et al.  The current conveyor—A new circuit building block , 1968 .

[14]  J.E.D. Hurwitz,et al.  Extended Dynamic Range From a Combined Linear-Logarithmic CMOS Image Sensor , 2006, IEEE Journal of Solid-State Circuits.

[15]  Tobi Delbrück,et al.  Adaptive photoreceptor with wide dynamic range , 1994, Proceedings of IEEE International Symposium on Circuits and Systems - ISCAS '94.

[16]  Jan Van der Spiegel,et al.  Low Fixed Pattern Noise Current-mode Imager Using Velocity Saturated Readout Transistors , 2007, 2007 IEEE International Symposium on Circuits and Systems.

[17]  V. Gruev,et al.  Low Power Programmable Current Mode Computational Imaging Sensor , 2012, IEEE Sensors Journal.

[18]  Viktor Gruev,et al.  Linear current mode image sensor with focal plane spatial image processing , 2010, Proceedings of 2010 IEEE International Symposium on Circuits and Systems.

[19]  P. Noble,et al.  Self-scanned silicon image detector arrays , 1968 .

[20]  Jan Van der Spiegel,et al.  Current-mode image sensor with 1.5 transistors per pixel and improved dynamic range , 2008, 2008 IEEE International Symposium on Circuits and Systems.

[21]  Jan Van der Spiegel,et al.  Current Mode Image Sensor With Two Transistors per Pixel , 2010, IEEE Transactions on Circuits and Systems I: Regular Papers.

[22]  Eric R. Fossum,et al.  CMOS image sensors: electronic camera on a chip , 1995, Proceedings of International Electron Devices Meeting.

[23]  A. Himmi,et al.  A CMOS Current-Mode Active Pixel Sensor for High Energy Physics and Biomedical Imaging Applications , 2009, IEEE Transactions on Nuclear Science.

[24]  Bedabrata Pain,et al.  On-focal-plane signal processing for current-mode active pixel sensors , 1999 .

[25]  C.G. Sodini,et al.  The effect of high fields on MOS device and circuit performance , 1984, IEEE Transactions on Electron Devices.

[26]  Amine Bermak,et al.  CMOS Image Sensor with On-Chip Image Compression: A Review and Performance Analysis , 2010, J. Sensors.

[27]  Viktor Gruev,et al.  Advances in integrated polarization image sensors , 2009, 2009 IEEE/NIH Life Science Systems and Applications Workshop.

[28]  Ralph Etienne-Cummings,et al.  Neuromorphic vision sensors , 1996 .

[29]  Jan Van der Spiegel,et al.  A CMOS linear voltage/current dual-mode imager , 2006, 2006 IEEE International Symposium on Circuits and Systems.

[30]  A. El Gamal,et al.  CMOS image sensors , 2005, IEEE Circuits and Devices Magazine.

[31]  Ralph Etienne-Cummings,et al.  Linear current mode imager with low fix pattern noise , 2004, 2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512).

[32]  A. Bermak,et al.  An 84 pW/Frame Per Pixel Current-Mode CMOS Image Sensor With Energy Harvesting Capability , 2012, IEEE Sensors Journal.