Extension of the Dynamic Range in the CMOS Active Pixel Sensor Using a Stacked Photodiode and Feedback Structure

Abstract

This paper presents an extension of the dynamic range in a complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) using a stacked photodiode and feedback structure. The proposed APS is composed of two additional MOSFETs and stacked P+/N-well/P-sub photodiodes as compared with a conventional APS. Using the proposed technique, the sensor can improve the spectral response and dynamic range. The spectral response is improved using an additional stacked P+/N-well photodiode, and the dynamic range is increased using the feedback structure. Although the size of the pixel is slightly larger than that of a conventional three-transistor APS, control of the dynamic range is much easier than that of the conventional methods using the feedback structure. The simulation and measurement results for the proposed APS demonstrate a wide dynamic range feature. The maximum dynamic range of the proposed sensor is greater than 103 dB. The designed circuit is fabricated by the 0.35-m 2-poly 4-metal standard CMOS process, and its characteristics are evaluated.

Dynamic Range Extension of CMOS Image Sensor with Column Capacitor and Feedback Structure

“…또한, 이미지 센서에서 동작 범위 향상은 얻을 수 있 는 정보의 양을 확장시키고, 이를 통해 많은 응용분야에 적용 하고 있다 [7][8][9][10][11]. 동작 범위 향상을 위한 방법에는 선형 및 비선 형 영상을 결합하는 방법(linear-logarithmic) [12][13][14][15], 중간 펄스 (middle level pulse)에 의한 방법 [16][17][18] This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License(http://creativecommons.org/ licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.…”