CMOS (complementary metal-oxide semiconductor transistor) biomedical signal acquisition unit in differential capacitance network feedback structure

Abstract

The invention discloses a CMOS (complementary metal-oxide semiconductor transistor) biomedical signal acquisition unit in a differential capacitance network feedback structure. The CMOS biomedical signal acquisition unit comprises a differential preamplifier, a differential variable gain amplifier and a differential four-order switch capacitance filter. A positive output end of the differential preamplifier is connected with a reverse input end of the differential variable gain amplifier, a reverse output end of the differential preamplifier is connected with a positive input end of the differential variable gain amplifier, a positive output end of the differential variable gain amplifier is connected with a positive input end of the differential four-order switch capacitance filter, and a reverse output end of the differential variable gain amplifier is connected with a reverse input end of the differential four-order switch capacitance filter. Creatively, the differential capacitance feedback network structure is adopted in the preamplifier in the field of biomedical signal acquisition, and common mode rejection ratio of the acquisition circuit is increased while capacitance of a capacitor is reduced.

Description

technical field [0001] The invention relates to the interdisciplinary technical fields of circuits and systems, microelectronics, integrated circuit design methodology and biomedical electronics, and in particular to a CMOS biomedical signal collector with a differential capacitance network feedback structure. Background technique [0002] my country is the country with the largest population in the world, which will inevitably lead to the largest demand for general medical services; moreover, the problem of population aging in my country is becoming more and more prominent, which has brought a heavy burden to my country's current medical system. [0003] On the other hand, with the acceleration of people's life rhythm, work pressure is increasing, and the number of people in a sub-health state is also increasing. Heart disease, high blood pressure, and diabetes have become the three major killers affecting people's health. Early diagnosis and timely treatment of sudden dise...

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Problems solved by technology

[0005] 1. Based on the structure of the instrumentation operational amplifier, the structure has good common-mode rejection capability and high input impedance; however, due to the strict matching of the two input operational amplifiers in the circuit, it is difficult to achieve high precision matching; in addition, due to the use of three operational amplifiers in the structure, power consumption and noise are relatively large

[0006] 2. Based on the chopper amplifier structure, this structure has low noise characteristics; but due to the use of chopper technology, the power consumption and area are relatively large, and it is not suitable for the detection of implantable in vivo signals

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