Bridge type input resistance negative feedback CMOS (Complementary Metal Oxide Semiconductor) pre-amplifying circuit

Abstract

The invention discloses a bridge type input resistance negative feedback CMOS (Complementary Metal Oxide Semiconductor) pre-amplifying circuit, which consists of an input part and an amplification part, wherein the input part is directly coupled with the amplification part. According to the circuit, a balance bridge type input structure is adopted for the input part, 1 kilo-ohm bias resistance is adopted for each of two branch circuits of the input part, one branch circuit is connected with a detector to form a path, the other branch circuit is connected with a blind pixel to form another path, and the two paths form the balance bridge type input structure; in order to meet the requirements of different amplification factors and achieve adaptability to the amplification readout of detector signals with different response ratios, a variable gain resistance negative feedback structure is adopted for the amplification part, selectable 5, 2 or 1 meg-ohm feedback resistance is adopted between the negative input end and the output end of the amplification part, and feedback resistances with different magnitudes are formed under the control of two MOS switches; in order to enable the circuit to work at low temperature of liquid nitrogen, a common-source common-gate structure is adopted for a differential amplifier in the amplification part, and the differential amplifier is powered by positive and negative power supplies.

Description

technical field [0001] The invention relates to a CMOS circuit, in particular to a CMOS pre-amplifier circuit with negative feedback of a bridge input resistance. Background technique [0002] In the field of aerospace remote sensing, infrared detector components are the core components of infrared imaging systems. Because photoconductive infrared detectors have great advantages in the long-wave field, most long-wave infrared detection uses photoconductive infrared detectors. The internal resistance is very low, generally lower than 100 ohms, and it works at the low temperature of liquid nitrogen, which puts forward higher requirements for the circuit interconnected with this type of detector. Work in liquid nitrogen cryogenics. At present, most of the long-wave photoconductive infrared detector signal readout adopts the design method of separating the detector and the circuit. The detector works at low temperature, and the circuit works at normal temperature. The signal is...

AI Technical Summary

Problems solved by technology

[0004] The present invention proposes a CMOS pre-amplifier circuit, which adopts a bridge input mode in the input part, which overcomes the problem that the existing CMOS circuit does not match the low-impedance detector, and the circuit is suitable for low-impedance detector signals below 100 ohms. Amplification can also work normally at the low temperature of liquid nitrogen, so that the CMOS pre-amplifier circuit and the detector can work normally at the low temperature of liquid nitrogen after interconnection, which overcomes the fact that the current detector works at low temperature and the circuit works at normal temperature , the disadvantage that the signal is extremely easy to cause interference during transmission

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