A CMOS image sensor using floating capacitor load readout operation

S. Wakashima; Y. Goda; T.L. Li; R. Kuroda; S. Sugawa

doi:10.1117/12.2004892

19 February 2013 A CMOS image sensor using floating capacitor load readout operation

S. Wakashima, Y. Goda, T.L. Li, R. Kuroda, S. Sugawa

Proceedings Volume 8659, Sensors, Cameras, and Systems for Industrial and Scientific Applications XIV; 86590I (2013) https://doi.org/10.1117/12.2004892
Event: IS&T/SPIE Electronic Imaging, 2013, Burlingame, California, United States

Abstract

In this paper, a CMOS image sensor using floating capacitor load readout operation has been discussed. The floating capacitor load readout operation is used during pixel signals readout. And this operation has two features: 1. in-pixel driver transistor drives load capacitor without current sources, 2. parasitic capacitor of pixel output vertical signal line is used as a sample/hold capacitor. This operation produces three advantages: a smaller chip size, a lower power consumption, and a lower output noise than conventional CMOS image sensors. The prototype CMOS image sensor has been produced using 0.18 μm 1-Poly 3-Metal CMOS process technology with pinned photodiodes. The chip size is 2.5 mm^H x 2.5 mm^V, the pixel size is 4.5 μm^H x 4.5 μm^V, and the number of pixels is 400^H x 300^V. This image sensor consists of only a pixel array, vertical and horizontal shift registers, column source followers of which height is as low as that of some pixels and output buffers. The size of peripheral circuit is reduced by 90.2 % of a conventional CMOS image sensor. The power consumption in pixel array is reduced by 96.9 %. Even if the power consumption of column source follower is included, it reduced by 39.0 %. With an introduction of buried channel transistors as in-pixel driver transistors, the dark random noise of pixels of the floating capacitor load readout operation CMOS image sensor is 168 μV_rms. The noise of conventional image sensor is 466 μV_rms; therefore, reduction of 63.8 % of noise was achieved.

Citation Download Citation

S. Wakashima, Y. Goda, T.L. Li, R. Kuroda, and S. Sugawa "A CMOS image sensor using floating capacitor load readout operation", Proc. SPIE 8659, Sensors, Cameras, and Systems for Industrial and Scientific Applications XIV, 86590I (19 February 2013); https://doi.org/10.1117/12.2004892

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available