Dual source follower pixel cell architecture

Abstract

Techniques for providing a pixel cell which includes two source follower transistors. In an embodiment, a first source follower transistor of a pixel cell and a second source follower transistor of the pixel cell are coupled in parallel with one another, where the source follower transistors are each coupled via their respective gates to a floating diffusion node of the pixel cell. In another embodiment, the first source follower transistor and second source follower transistor each operate based on a voltage of the floating diffusion node to provide a respective component of an amplification signal, where the pixel cell outputs an analog signal based on the amplification signal.

Description

technical field [0001] The present invention relates generally to image sensors, and specifically but not exclusively to CMOS image sensors. Background technique [0002] Image sensors have become ubiquitous. They are widely used in digital still cameras, cellular phones, security cameras, as well as in medical, automotive and other applications. The need for higher resolution and lower power consumption has driven further miniaturization and integration of these image sensors. Accordingly, the technology used to manufacture image sensors, such as CMOS image sensors ("CIS"), has continued to advance rapidly. [0003] 1 is a circuit diagram showing a pixel circuit 100 including two four-transistor ("4T") pixel cells Pa110 and Pb120 of a conventional pixel array. In FIG. 1 , pixel cells Pa110 and Pb120 are arranged in two rows and one column. Pal 10 and Pb 120 each include the same conventional pixel cell architecture, where each pixel cell includes a photosensitive elemen...

AI Technical Summary

Problems solved by technology

Such smaller signals are more susceptible to various types of noise such as RTS noise

Efficiently generating and processing such signals poses a challenge for next-generation image sensors

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