Title :
CMOS active pixel sensor with variable dynamic range using a double-photodiode feedback structure
Author :
Jo, Sung-Hyun ; Bae, Myunghan ; Jung, Joontaek ; Shin, Jang-Kyoo
Author_Institution :
Sch. of Electron. Eng., Kyungpook Nat. Univ., Daegu, South Korea
Abstract :
A double-photodiode feedback structure to extend the dynamic range (DR) of the CMOS active pixel sensor (APS) has been proposed in this paper. Since the proposed APS requires one additional photodiode and two additional nMOSFETs in comparison with a conventional 3-transistor (TR) APS, the size of pixel is slightly larger than that of conventional 3-TR APS. However, extension of the dynamic range is much easier than conventional methods by adjusting the reset voltage and photo current of the additional photodiode. The proposed APS exhibits a wide and variable dynamic range with high sensitivity at low illumination and low sensitivity at high illumination.
Keywords :
CMOS image sensors; MOSFET; circuit feedback; photoconductivity; photodiodes; sensitivity; CMOS active pixel sensor; complementary metal oxide semiconductor image sensor; double-photodiode feedback structure; illumination; nMOSFET; photocurrent; reset voltage; sensitivity; variable dynamic range; CMOS image sensors; Dynamic range; Lighting; Photodiodes; Pixel; Simulation; CMOS image sensor; active pixel sensor; double-photodiode structure; dynamic range;
Conference_Titel :
Instrumentation and Measurement Technology Conference (I2MTC), 2011 IEEE
Conference_Location :
Binjiang
Print_ISBN :
978-1-4244-7933-7
DOI :
10.1109/IMTC.2011.5944353
