Compensation for Process and Temperature Dependency in a CMOS Image Sensor

Sensors

卷:19

Albert Theuwissen¹  Shuang Xie¹ 

[1] EI Lab, Delft University of Technology, 2628 CD Delft, The Netherlands;

关键词: temperature sensors;    delta-sigma (Δ-σ) modulator;    CMOS image sensor (CIS);    thermal compensation;    dark current;    dark signal non-uniformity (DSNU);    process variability;    process variations;    conversion gain (CG);   

DOI  :  10.3390/s19040870

来源: DOAJ

【 摘 要 】

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 °C. Dark signal and CG’s thermal dependencies are compensated using the on-chip temperature sensors by at least 79% and 87%, respectively.

【 授权许可】

Unknown