High dynamic range reading circuit based on backside illuminated image sensor

Abstract

The invention discloses a high dynamic range reading circuit based on a backside illuminated image sensor, which comprises an analog correlation sampling and programmable gain amplifier, and is characterized in that a voltage signal read from a pixel is amplified and then transmitted to a lower-level analog-to-digital converter through a switch switching strategy of multiple times of sampling andholding and adjustment to a set gain; the folding circulating analog-to-digital converter is used for quantizing the signals subjected to preceding-stage preventive large sampling; the digital correlation sampling merging logic circuit is used for obtaining a real digital quantized signal; the time sequence control circuit is used for controlling the analog-to-digital converters in each column line by line; an input signal sequentially passes through the analog correlation sampling and programmable gain amplifier, the folding circulation type analog-to-digital converter and the digital correlation sampling merging logic circuit and then outputs a quantized signal, and a clock signal passes through the sequential control circuit and then is input into the folding circulation type analog-to-digital converter and the digital correlation sampling merging logic circuit. Quantization errors are reduced, the dynamic range is enlarged, and the overall power consumption and area of the readingcircuit are reduced.

Description

technical field [0001] The invention belongs to the technical field of low-power integrated circuits, in particular to a high dynamic range readout circuit based on a back-illuminated image sensor, and relates to the fields of bionic navigation, target detection and other embedded systems and consumer electronics products. Background technique [0002] With the continuous advancement of technology and the continuous improvement of people's living standards, consumer-grade digital cameras, portable smart phones and other imaging equipment have become necessities. The collection and processing of image information plays an important role in various fields such as consumption, medical treatment, security and aerospace. Therefore, new requirements such as low power consumption, high dynamic range, and high speed are put forward for the readout circuit of the image sensor. [0003] In the readout circuits used in bionic navigation and target detection systems, with the improveme...

AI Technical Summary

Problems solved by technology

This type of structure generally works at a low rate, on the order of hundreds of kHz, and the accuracy is not high, and the number of bits is 8 to 12 bits; however, when the number of ADC bits exceeds 12 bits or the clock speed reaches the order of hundreds of MHz, the integral ADC It is difficult to achieve both power consumption and area, resulting in a decrease in the signal accuracy of pixel readout

[0005] Therefore, the dynamic range of the traditional readout circuit is limited, and the clock speed needs to be continuously increased to make up for the defects of the progressive exposure method, but the high-speed comparator, amplifier and other circuits will consume more power consumption

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