CMRR in Voltage-Op-Amp-Based Current-Mode Instrumentation Amplifiers (CMIA)

Author

Azhari, Seyed Javad ; Fazlalipoor, Hossein

Author_Institution

Electron. Res. Center, Iran Univ. of Sci. & Technol., Tehran

Volume

58

Issue

3

fYear

2009

fDate

3/1/2009 12:00:00 AM

Firstpage

563

Lastpage

569

Abstract

The common-mode rejection ratio (CMRR) of a power-supply current-sensing current-mode instrumentation amplifier (CMIA) has theoretically been analyzed and formulated. The theory was further investigated by doing experiments using mu A741 and TL071 as op-amps and CA3096 transistors as the current mirrors of the CMIA. Both theoretical and practical investigations proved that both the dc and ac performances of CMRR depend on the matching status of parameters such as CMRR, open-loop gain A, gain-bandwidth product GB, and the output resistance R _O of the input op-amps of the CMIA. It has also been shown that, in the CMIA, unlike the voltage-mode instrumentation amplifier, voltage gain is independent of the bandwidth.

Keywords

bipolar transistor circuits; current mirrors; current-mode circuits; instrumentation amplifiers; operational amplifiers; CA3096 bipolar junction transistor; CMIA; CMRR; common-mode rejection ratio; current mirror; current-sensing current-mode instrumentation amplifier; gain-bandwidth; open-loop gain; voltage-op-amp; Common-mode rejection ratio (CMRR); current-mode instrumentation amplifier (CMIA); gain bandwidth of CMIA; voltage op-amp (VOA)-based CMIA;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/TIM.2008.2005559

Filename

4637875