CMRR Analysis of the 3 Op-Amp Instrumentation Amplifier with Noise

2014 ◽  
Vol 488-489 ◽  
pp. 1096-1099
Author(s):  
Tie Feng Wu ◽  
Zhi Chao Zhao ◽  
De Wei Dai ◽  
Shun Ji Piao ◽  
Jing Li
Keyword(s):  
Instrumentation Amplifier ◽  
Weak Signal ◽  
Common Mode ◽  
Common Mode Rejection Ratio ◽  
Application Range ◽  
Op Amp ◽  
Rejection Ratio ◽  
The Common

This paper researches the common mode rejection ratio (CMRR) of 3 op-amp instrumentation amplifier of amplifying weak signal and presents a new calculation modal considering noise, non-ideal amplifiers, matched resistor and application restricted by the factors of affecting CMRR. At last, a instrumentation amplifier was designed and built and its measured and computed results of modal are compared. The results show that this modal presented enhances calculating precision and extends application range of instrumentation amplifier. It is valid and reasonable.

scholarly journals An improved AC-amplifier for electrophysiology

2009 ◽  
Vol 19 (1) ◽  
pp. 7-12
Author(s):  
Nikola Jorgovanovic ◽  
Dubravka Bojanic ◽  
Vojin Ilic ◽  
Darko Stanisic
Keyword(s):  
Dynamic Range ◽  
Cutoff Frequency ◽  
Instrumentation Amplifier ◽  
Single Chip ◽  
Common Mode ◽  
Differential Signal ◽  
Op Amp ◽  
Chip Technology ◽  
The Common ◽  
Dc Component

We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA). The design target was to increase the common mode rejection ratio (CMRR), thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier's first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper.

Fully Differential Class-AB OTA with Improved CMRR

2017 ◽  
Vol 26 (11) ◽  
pp. 1750169 ◽  
Author(s):  
Francesco Centurelli ◽  
Pietro Monsurrò ◽  
Gaetano Parisi ◽  
Pasquale Tommasino ◽  
Alessandro Trifiletti
Keyword(s):  
Cmos Technology ◽  
Current Mirror ◽  
Differential Mode ◽  
Common Mode ◽  
Common Mode Rejection Ratio ◽  
Class Ab ◽  
Fully Differential ◽  
Rejection Ratio ◽  
Mode Behavior ◽  
The Common

This paper presents a fully differential class-AB current mirror OTA that improves the common-mode behavior of a topology that presents very good differential-mode performance but poor common-mode rejection ratio (CMRR). The proposed solution requires a low-current auxiliary circuit driven by the input signal, to compensate the effect of the common-mode input component. Simulations in 40-nm CMOS technology show a net reduction of common-mode gain of more than 90[Formula: see text]dB without affecting the differential-mode behavior; a sample-and-hold amplifier exploiting the proposed amplifier has also been simulated.

scholarly journals Common Mode Voltage Removal using New Balancing Technique for Extraction of Low Level Differential Signals Embedded in Large Common Mode Voltages

2019 ◽  
Vol 9 (1) ◽  
pp. 5533-5538
Keyword(s):  
Differential Amplifier ◽  
Individual Values ◽  
Common Mode ◽  
Common Mode Rejection Ratio ◽  
Rejection Ratio ◽  
Common Mode Voltage ◽  
Wide Range ◽  
The Common ◽  
Specific Band ◽  
The Individual

The paper proposes a method based on new principle for removal of common mode voltages (CMVs) present in the differential signals # . These CMVs can be reduced nearly to zero without using any components with tight tolerances which is achieved using a new balancing technique. It is proved that the performance of the circuit depends only on the ratios and not on the individual values of the resistors because of which the performance of the circuit is not affected over the wide range of temperature. The circuit based on this principle was designed, constructed, tested and results are reported in this paper. Unlike the conventional techniques which use filters for removal of the common mode signals in specific band of the frequencies, the method reported here removes common mode signals of all known and unknown frequencies. Using this method, it is possible to extract very low values of the differential signals in the range of few microvolts where common mode voltages can be as high as few volts. It is possible to improve the effective common mode rejection ratio (CMRR) of any differential amplifier by a factor of more than 103 to 104 with this method.

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