Compensation for Process and Temperature Dependency in a CMOS Image Sensor

Shuang Xie, Albert Theuwissen

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)
99 Downloads (Pure)

Abstract

This paper analyzes and compensates for process and temperature dependency among a (Complementary Metal Oxide Semiconductor) CMOS image sensor (CIS) array. Both the analysis and compensation are supported with experimental results on the CIS’s dark current, dark signal non-uniformity (DSNU), and conversion gain (CG). To model and to compensate for process variations, process sensors based on pixel source follower (SF)’s transconductance g m,SF have been proposed to model and to be compared against the measurement results of SF gain A SF . In addition, A SF ’s thermal dependency has been analyzed in detail. To provide thermal information required for temperature compensation, six scattered bipolar junction transistor (BJT)-based temperature sensors replace six image pixels inside the array. They are measured to have an untrimmed inaccuracy within ±0.5 ⁰C. Dark signal and CG’s thermal dependencies are compensated using the on-chip temperature sensors by at least 79% and 87%, respectively.

Original languageEnglish
Article number870
Pages (from-to)1-15
Number of pages15
JournalSensors (Switzerland)
Volume19
Issue number4
DOIs
Publication statusPublished - 2019

Keywords

  • CMOS image sensor (CIS)
  • Conversion gain (CG)
  • Dark current
  • Dark signal non-uniformity (DSNU)
  • Delta-sigma (Δ-σ) modulator
  • Process variability
  • Process variations
  • Temperature sensors
  • Thermal compensation

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