Switchable conversion gain image sensor with improved uniformity and methods thereof

Abstract

A switchable conversion gain image sensor and a method is described. The switchable conversion gain image sensor includes a pixel cell array including a plurality of pixel cells arranged in rows and columns. Individual pixel cells each include one or more photodiodes configured to generate image charge in response to incident light, a plurality of conversion gain capacitors, including a high conversion gain capacitor and a low conversion gain capacitor, and a switch transistor coupled between the high conversion gain capacitor and the low conversion gain capacitor. The high conversion gain capacitor and the low conversion gain capacitor are selectively coupled to receive the image charge from the one or more photodiodes. The pixel cell array is segmented into a plurality of zones. The low conversion gain capacitor for the individual pixel cells physically vary on a zone-by-zone basis.

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