Direct-current reconstruction circuit for CCD signal processing

Abstract

The invention discloses a DC reconstruction circuit for CCD signal processing, and the circuit comprises a bias circuit which generates a DC voltage recovery reference voltage according to an externalbias signal; a control circuit which is used for receiving a function enabling signal through the enabling end, closing a direct-current reconstruction circuit when the function enabling signal is invalid, and opening the direct-current reconstruction circuit according to a control time sequence when the function enabling signal is valid; and a blocking capacitor used for eliminating relatively large direct-current common-mode voltage of the CCD signal and re-establishing relatively low direct-current common-mode voltage suitable for a subsequent processing circuit. According to the direct current reconstruction circuit provided by the invention, direct current voltage recovery can be continuously carried out in all effective CCD pixel periods, and the direct current recovery voltage precision can be effectively improved.

Description

technical field [0001] The invention relates to a DC reconstruction circuit for CCD signal processing, which belongs to the technical field of circuit design. Background technique [0002] Commonly used in still cameras or video cameras, charge-coupled device (CCD) image sensors consist of an array of individual pixels, each of which collects photons incident on the image sensor. The number of photons collected by each pixel is converted into a charge by a photodiode, which is then converted to an analog voltage and converted to a digital value by an analog front-end circuit (AFE), so that the information obtained from an individual pixel can usually be processed by a digital signal Processor into the final digital image. [0003] Since the CCD image sensor generally uses a higher power supply voltage, usually about 15V, the output signal of the CCD will have a high DC component, and the voltage of the analog front-end circuit (AFE) is generally below 5V, so the output sign...

AI Technical Summary

Problems solved by technology

A row of CCD photosensitive elements generally has hundreds to thousands of pixels. Due to the charge leakage of the capacitor, the traditional DC reconstruction circuit cannot achieve high-precision voltage recovery; There is a difference in voltage, and traditional DC reconstruction circuits cannot track this difference, reducing the accuracy of voltage restoration

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