Variable gain correlated double sampling circuit with baseline adjustment

Abstract

The invention relates to the technical field of signal reading of charge-coupled devices and the technical field of integrated circuits, and specifically relates to a variable gain correlated double sampling circuit with baseline adjustment. The variable gain correlated double sampling circuit with baseline adjustment comprises a first switched capacitor network and an amplifier; a charge retention node of the first switched capacitor network is connected with a negative input end of the amplifier, an output node of the first switched capacitor network is connected with an output end of the amplifier, and a positive input end of the amplifier is connected with an input common mode level. The variable gain correlated double sampling circuit with baseline adjustment, provided by the invention, can simultaneously realize correlated double sampling, baseline adjustment and gain variation under the condition of only using one amplifier, and has the advantages, such as simple circuit structure, low power consumption, flexible configuration and high applicability; peripheral and follow-up processing circuits of the circuit are simplified further, the dynamic range of a follow-up analog-digital converter is used fully; and by a fully-differential realization mode of the circuit, common-mode interference rejection capability is improved.

Description

Technical field [0001] The invention relates to the technical field of charge-coupled device (Charge-coupled Device, CCD for short) signal readout technology and the technical field of integrated circuits, and in particular to a variable gain correlation double sampling circuit with baseline adjustment. Background technique [0002] A charge-coupled device is a semiconductor device that can convert optical images into digital signals. CCD is widely used in digital photography, astronomy, especially optical telemetry technology, optical and spectrum telescope and high-speed photography technology. The readout of CCD signals generally requires a correlated double sampling circuit to remove reset burrs, reduce KT / C noise, and suppress 1 / f noise. [0003] The traditional correlated double sampling circuit such as figure 1 As shown, two amplifiers are included, a driver amplifier and a high-impedance amplifier, and the high-impedance amplifier is generally implemented by an amplifier w...

AI Technical Summary

Problems solved by technology

[0005] Therefore, the traditional correlated double-sampling circuit not only has a complex structure and high power consumption, but also has weak anti-common-mode interference ability, and the utilization rate of the input dynamic range of the subsequent analog-to-digital converter is low.

On the other hand, in subtractive sampling mode, since the sampling switch is located in the signal path, new KT / C noise will also be introduced

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