Title

A digital vision sensor with pixel level analog-to-digital converter

Document Type

Conference Proceeding

Publisher

SPIE

Faculty

Computing, Health and Science

School

Engineering and Mathematics

RAS ID

2054

Comments

Originally published as: Bermak, A., Bouzerdoum, A., & Eshraghian, K. (2001, November). Digital vision sensor with pixel level analog-to-digital converter. In Electronics and Structures for MEMS II (Vol. 4591, pp. 353-359). International Society for Optics and Photonics. Original article available here

Abstract

In this paper we propose an on-pixel Analog-to-Digital converter based on pulse frequency modulation (PFM) scheme. This PFM based converter presents a very viable solution for pixel level based ADC. It uses a very simple and robust circuit that can be implemented in a compact area resulting in a 23% fill-factor. The low-light performance of the PFM converter is improved by using a wider counting period. By modifying the counting period, it is possible to change the saturation level of the ADC and hence improve the dynamic range of the sensor. Image lag is eliminated in the PFM On-pixel ADC since a reset of the photodetector is performed after the conversion period. In addition, the PFM on-pixel ADC has a very important advantage: it is insensitive to variations of the supply and reference voltages. The pixel based ADC has been designed and fabricated using CMOS 0.25 μm technology.

DOI

10.1117/12.449166

Access Rights

free_to_read

 
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Link to publisher version (DOI)

10.1117/12.449166