Image sensor pixel with changeable conversion gain and working method thereof

Abstract

The invention discloses an image sensor pixel with the changeable conversion gain and a working method thereof. The image sensor pixel comprises a first photodiode, a charge transmission transistor, a first reset transistor, a source following transistor, a selection transistor, a floating active area, a second photodiode, a second reset transistor, a capacitor and a switch transistor which are arranged in a semiconductor substrate. The drain electrode end of the switch transistor is connected with the floating active area, the source electrode end of the switch transistor is connected with one electrode end of the capacitor, the grid electrode end of the switch transistor is connected with the second photodiode, the other electrode end of the capacitor is connected with the floating active area, the source electrode end of the second reset transistor is connected with the second photodiode, and the drain electrode end of the second reset transistor is connected with a power source. The photovoltaic conversion gain for lowering the sensor pixel in the high illumination environment is used for achieving the purpose of delaying the pixel saturation time, the problem that in the prior art, real object information in the outdoor high illumination environment cannot be easily collected is solved, and the quality of images output by an image sensor is improved.

Description

technical field [0001] The invention relates to an image sensor pixel, in particular to an image sensor pixel with variable conversion gain and a working method thereof. Background technique [0002] Image sensors have been widely used in digital cameras, mobile phones, medical devices, automobiles and other applications. In particular, the rapid development of the technology for manufacturing CMOS (Complementary Metal Oxide Semiconductor) image sensors has made people have higher requirements for the output image quality of the image sensor. [0003] In the prior art, a CMOS image sensor generally adopts a pixel structure with a linear photoelectric response function. Such as figure 1 Shown are CMOS image sensor pixels, also known in the art as 4T (four transistor) active pixels. The components of a 4T active pixel include: a photodiode 101, a charge transfer transistor 102, a reset transistor 103, a source follower transistor 104, a row selection transistor 105, and a c...

AI Technical Summary

Problems solved by technology

In the outdoor environment, the linear sensor is not easy to collect the physical information of the high lighting environment, thus reducing the output image quality of the sensor

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