A multisampling time-domain CMOS imager with synchronous readout circuit

De Souza Campos F., Marinov O., Faramarzpour N., Saffih F., Deen M. J., Swart J. W.

SBCCI 2007: 20th Symposium on Integrated Circuits and System Design, Copacabana, Rio de Janeiro, Brezilya, 3 - 06 Eylül 2007, ss.53-58 identifier

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Doi Numarası: 10.1145/1284480.1284502
  • Basıldığı Şehir: Copacabana, Rio de Janeiro
  • Basıldığı Ülke: Brezilya
  • Sayfa Sayıları: ss.53-58
  • Anahtar Kelimeler: Active pixel sensor, CMOS imager, Dynamic range, Fill-factor
  • İstanbul Gelişim Üniversitesi Adresli: Hayır

Özet

A novel multisampling time-domain architecture for CMOS imagers with synchronous readout and wide dynamic range is proposed. The architecture was implemented in a prototype of imager with 32x32 pixel array fabricated in AMS CMOS 0.35νm and was characterized for sensitivity and color response. The pixel is composed of an n+/psub photodiode, a comparator and a D flip-flop having 16% fill-factor and 30νmx26νm dimensions. The multisampling architecture requires only a 1 bit per pixel memory instead of 8 bits which is typical for time-domain active pixel architectures. The advantage is that the number of transistors in the pixel is low, saving area and providing higher fill-factor. The maximum frame rate is analyzed as a function of number of bits and array size. The analysis shows that it is possible to achieve high frame rates and operation in video mode with 10 bits. Also, we present analysis for the impact of comparator offset voltage in the fixed pattern noise. Copyright 2007 ACM.