Cmos optical sensor with a scalable repairing scheme for repair defective readout channels providing a further function of row noise suppression and corresponding row noise suppression method

Abstract

A CMOS optical sensor comprises spare readout channels to replace readout channels found defective at the end of the manufacturing process. These spare readout channels are dispatched over the width of the optical sensor (corresponding to the row direction) in the form of spare groups G, G, Gmof m spare readout channels each, m integer at least equal to 1. Each spare group is inserted between two successive default groups Gnand Gnof n default readout channels each and coupling means SWare configured to replace a defective default readout channel in a default group as well as any default readout channels of the group between the defective one and the spare group next to the default group of concern. Advantageously, for a row Rowbeing currently selected for CDS reading each pixel in the row, a row noise level Vis obtained from the A spare readout channels that are not used in the implemented repairing scheme, by sampling an analogic DC reference signal by each of the A spare readout channels and averaging the A values Spobtained. The row reference value Vis then subtracted from each of the pixel digital signal Soutputs for the current selected row, to finally obtain a signal value dwith row noise suppression.