A low-photocurrent CMOS retinal focal-plane sensor with pseudo-BJT smoothing network and adaptive current schmitt trigger for scanner applications

Chung-Yu Wu*, Cheng Ta Chiang

*Corresponding author for this work

Research output: Contribution to conferencePaper

1 Scopus citations

Abstract

In this paper, a new structure of low-photocurrent CMOS retinal focal-plane sensor with pseudo-BJT smoothing network and adaptive current Schmitt trigger is proposed. The proposed structure is very simple and compact. This new circuit can be easily implemented in CMOS technology with a small chip area. Besides, another innovation of this circuit is that the proposed circuit could be operated for low-induced current level (pA), and the current hysteresis of proposed current Schmitt trigger could be adjusted adaptively according to the value of induced photocurrent. In this paper, the detection of static and moving objects, such as a moving white bar, are proven by projecting a pattern through HSPICE simulation. The proposed retinal focal-plane sensor includes 32 × 32 pixel array with a pixel size of 70 × 70 μm 2. The fill factor is 75% and the total chip area is 3000 × 3030 μm2. It is with fully functional 32 × 32 implementations consuming less than 8.8 μW per pixel at 3.3 V. Measurement results present the proposed retinal focal-plane sensor could be successfully used in character recognition, such as pen-scanner or etc.

Original languageEnglish
Pages1147-1152
Number of pages6
DOIs
StatePublished - 1 Dec 2003
EventSecond IEEE International Conference on Sensors: IEEE Sensors 2003 - Toronto, Ont., Canada
Duration: 22 Oct 200324 Oct 2003

Conference

ConferenceSecond IEEE International Conference on Sensors: IEEE Sensors 2003
CountryCanada
CityToronto, Ont.
Period22/10/0324/10/03

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