Current-mode CMOS imaging sensor with velocity saturation mode of operation and feedback mechanism

Raphael Njuguna, Viktor Gruev

Research output: Contribution to journalArticlepeer-review


We present a complementary metal-oxide-semiconductor (CMOS) imaging sensor containing two novelties in the field of current mode sensing. First, the in-pixel read-out transistor operates in velocity saturation mode and allows for high linearity between integrated photo charges and output current of the pixel. Second, the column parallel read-out circuitry includes a novel current conveyor with a feedback mechanism, which improves linearity of the output current and leads to improvements in fixed pattern noise. Correlated double sampling, a noise reduction technique, is performed on-chip via current mode circuits to improve spatial noise characteristics of the imager. A prototype of the proposed imaging sensor was fabricated in 0.18 μ m triple well CMOS process. The sensor operation and measurements are presented.

Original languageEnglish (US)
Article number6644291
Pages (from-to)710-721
Number of pages12
JournalIEEE Sensors Journal
Issue number3
StatePublished - Mar 2014
Externally publishedYes


  • CMOS image sensors
  • current mode circuits
  • feedback mechanism
  • linear response
  • velocity saturation

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering


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