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

Volume

1

fYear

2003

Firstpage

323

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Electrical and Computer Engineering, 2003. IEEE CCECE 2003. Canadian Conference on

ISSN

0840-7789

Print_ISBN

0-7803-7781-8

Type

conf

DOI

10.1109/CCECE.2003.1226406

Filename

1226406