公开(公告)号：GB2498529A

公开(公告)日：2013-07-24

申请号：GB201200761

申请日：2012-01-17

Applicant: ST MICROELECTRONICS RES & DEV

Inventor： MOORE JOHN KEVIN ,  DUGGAL AMAR

IPC: H04N5/3745 ,  H01L27/14 ,  H04N5/335 ,  H04N5/357

Abstract: An image sensor comprising an array of pixels and first and second Analogue to Digital Convertors (ADCs) with a bias line common to both the ADCs and in which a positive feedback coupling (which may comprise a capacitor) is provided between the bias line and the output of each ADC. Each ADC may serve one column of pixels in the array and may be formed within and as part of the pixel structure. The bias line may be global to the pixel array and to every ADC or it may be split to form two or more localised bias lines with each of the localised bias lines being associated with a predetermined set of ADCs. At least one of the ADCs may comprise a multi-stage comparator having a positive feedback coupling between the output of one stage and a current source of a second preceding stage. Also disclosed is a mobile telephone comprising the disclosed image sensor. The positive feedback coupling of the invention is design to improve the noise performance of CMOS image sensors