Logarithmic polar CMOS image sensor capable of eliminating pixel noise

Abstract

The logarithmic polar CMOS image sensor capable of eliminating inherent fixed pixel noise has the first to the fourth transistors, photodiode and current source. The first transistor has the grid connected to the first coupling end in the first node and the highest voltage. The second transistor has the grid connected to the second coupling end of the first transistor in the second node and the first coupling end connected to the highest voltage. The third transistor has the grid coupled to the line selecting signal, the first coupling end connected to the second coupling end of the second transistor, and the second coupling end as the voltage output end. The fourth transistor has the grid coupled to the control signal and the first coupling end connected to the second node. The photodiode is connected between the second coupling end and the earth. The current source is connected between the second coupling end of the third transistor and the earth.

Description

technical field [0001] The present invention relates to a logarithmic mode CMOS image sensor, and more particularly to a pair that can eliminate in-pixel fixed pattern noise. Digital pole type complementary metal oxide semiconductor image sensor. Background technique [0002] A good image sensor should not only have high dynamic range (can increase the range of illumination), low dark current (applicable to low-light environment) and low power consumption (power dissipation), fast reading and The function of random access is also a very important part. Like the most commonly used Charge Coupled Device (CCD), although it has high dynamic range and low dark current, it is expensive due to its special process, and its drive circuit needs high voltage operation, so High power consumption, coupled with the characteristics of its own components, can not achieve random access. [0003] In contrast, the complementary metal oxide semiconductor image sensor has high quantum efficie...

AI Technical Summary

Problems solved by technology

However, it also has the problem of very large fixed noise due to the threshold voltage mismatch due to the process technology when the readout voltage is used.

In addition, those skilled in the art know that the logarithmic CMOS image sensor cannot perform Correlated Double Sampling (CDS) to eliminate fixed noise.

[0005] The present invention aims at the shortcomings of the logarithmic complementary metal oxide semiconductor image sensor itself, the fixed noise caused by the mismatch of critical voltage, which is also the biggest shortcoming of the logarithmic complementary metal oxide semiconductor image sensor.

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