On-Focal-Plane Signal Processing for Current-Mode Active Pixel Image Sensors

Abstract

On-focal-plane signal processing for current-mode active pixel sensor(APS) including fixed pattern noise (FPN) suppression and high resolution analog-to-digital conversion(ADC) is presented. An FPN suppression circuit that removes the offset current variation between pixels by using a combination of an n-type and a p-type current copier cell is described. Also, operation and performance of a current-mode second-order incremental Δ-Σ A/D converter with column parallel architecture and for high resolution and medium-slow-speed application is presented.