A SWITCHED MULTIDIFFERENTIAL OPERATIONAL AMPLIFIER FOR A MULTICHANNEL MEASURING SYSTEM 

Sergey V. Fedorov, Candidate of technical sciences, associate professor of the sub-department of aircraft manufacturing technology, Ufa University of Science and Technology (Kumertau Branch) (22A Gorkogo street, Kumertau, Republic of Bashkortostan, Russia), E-mail: proinfosystem@gmail.com 

Background. The purpose of this study is to design an amplifier that allows differential conversion of several input voltages with the possibility of multiplexing them, as well as having a lower zero offset voltage and a high commonmode attenuation coefficient than in operational and instrumental amplifiers. Materials and methods. Methods of converting sensor signals in multichannel measuring systems are considered. The disadvantages of these methods are the use of operational amplifiers that do not provide differential conversion of several input voltages, which requires an analog multiplexer to switch channels. Operational amplifiers do not have high intrinsic parameters. Multichannel measurement systems based on them require the presence of external elements that affect its quality indicators. Results. As a solution to eliminate these shortcomings, a scheme of a multidifferential operational amplifier with identical input differential stages and the possibility of switching them to connect and disconnect input signals has been developed. Conclusions. The simulation of the circuit in the Multisim environment provided the transmission characteristics for the differential and common-mode modes of a multidifferential amplifier. The analysis of the obtained results shows that the developed multidifferential amplifier has better intrinsic parameters than existing operational and instrumental amplifiers, and also allows you to exclude external elements of the circuit that affect its quality indicators. The difference between this scheme and existing multidifferential amplifiers is the possibility of switching the input differential signals of the sensors. Thus, it eliminates the use of an analog multiplexer for channel switching. 

multichannel measuring system, operational amplifier, switched multidifferential operational amplifier, common-mode input voltage attenuation coefficient, zero offset voltage, instrumental amplifier 

Fedorov S.V. A switched multidifferential operational amplifier for a multichannel measuring system. Izmerenie. Monitoring. Upravlenie. Kontrol' = Measuring. Monitoring. Management. Control. 2024;(1):14–21. (In Russ.). doi: 10.21685/2307-5538-2024-1-2