Title :
A new CMOS architecture for wide dynamic range image sensing
Author :
Tr?©panier, J. -L ; Sawan, M. ; Audet, Y.
Author_Institution :
Dept. of Electr. Eng., Ecole Polytech. de Montreal, Que., Canada
Abstract :
A CMOS image sensor with pixel level analog to digital conversion is presented. Each 13.8×13.8 μm2 pixel area contains a photodiode and a dynamic comparator using the maximum voltage swing available (0 V-1.8 V). The comparator does not need any bias current, is insensitive to fabrication process variations and the number of quantification levels provided could be programmed. A new method for scanning the columns of the pixel array is presented. Implemented with a self-timed circuit, it provides a faster readout while consuming less power. The system allows image captures at multiple exposure times, and the resulting values are delivered in floating digital format, offering the possibility to expand the intrascene dynamic range to more than 96 dB. The circuit was implemented in a CMOS 0.18 μm process.
Keywords :
CMOS image sensors; analogue-digital conversion; comparators (circuits); 0 to 1.8 V; 0.18 micron; CMOS architecture; CMOS image sensor; complementary metal-oxide semiconductor; dynamic comparator; floating digital format; image captures; intrascene dynamic range; maximum voltage swing; multiple exposure times; photodiode; pixel area; pixel array; pixel level analog to digital conversion; self-timed circuit; CMOS image sensors; CMOS process; CMOS technology; Charge coupled devices; Dynamic range; Image converters; Image generation; Image sensors; Logic circuits; Pixel;
Conference_Titel :
Electrical and Computer Engineering, 2003. IEEE CCECE 2003. Canadian Conference on
Print_ISBN :
0-7803-7781-8
DOI :
10.1109/CCECE.2003.1226406
