Indirect Current Feedback Instrumentation Amplifier with a Common Mode Input Range That Includes the Negative Rail

1992 ◽  
Author(s):  
Bernard J. van den Dool ◽  
Johan H. Huijsing
Keyword(s):  
Instrumentation Amplifier ◽  
Current Feedback ◽  
Common Mode ◽  
Input Range

A 3.6 μW 60 nV/sqrtHz Capacitively-Coupled Instrumentation Amplifier for Biopotential Signal Recordings

2015 ◽  
Vol 24 (06) ◽  
pp. 1550089 ◽  
Author(s):  
Yin Zhou ◽  
Xiaobo Wu ◽  
Peng Sun ◽  
Menglian Zhao
Keyword(s):  
Low Power ◽  
Low Noise ◽  
Instrumentation Amplifier ◽  
Cmos Process ◽  
Frequency Noise ◽  
Noise Power ◽  
Current Feedback ◽  
Common Mode ◽  
Capacitively Coupled ◽  
Offset Voltage

This paper presents a low-power low-noise instrumentation amplifier (IA) intended for biopotential signal recordings. The IA is designed based on a capacitively-coupled topology, which achieves wide input common-mode range, high common-mode rejection ratio (CMRR) and low power consumption. To reduce low-frequency noise and output ripple at the same time, a combination of chopping and ping-pong auto-zeroing techniques, which is normally used in current-feedback IAs, is introduced for the capacitively-coupled topology in this paper. An intrinsic adverse effect of the proposed structure which causes additional ripple is analyzed. The DC electrode offset voltage is suppressed and the input impedance is boosted through feedback techniques. An improved switched-capacitor common mode feedback (SC CMFB) circuit is also presented. Test results show that the IA achieves an equivalent input-referred noise power spectrum density of 60 nV/sqrtHz and a noise efficiency factor (NEF) of 5.58. The bandwidth is 0.5 Hz to 10 kHz, covering most biopotential recording applications. The IA was implemented in 0.18-μm CMOS process. It occupies 0.27 mm2 core area and consumes 3.6 μA from a 1 V supply.

scholarly journals Power Line Interference Reduction Technique with a Current-Reused Current-Feedback Instrumentation Amplifier for ECG Recording

2020 ◽  
Vol 10 (23) ◽  
pp. 8478
Author(s):  
Donggeun You ◽  
Hyunwoo Heo ◽  
Hyungseup Kim ◽  
Yongsu Kwon ◽  
Sangmin Lee ◽  
...  
Keyword(s):  
Continuous Time ◽  
Feedback Loop ◽  
Power Line ◽  
Reduction Technique ◽  
Instrumentation Amplifier ◽  
Current Feedback ◽  
Common Mode ◽  
Power Line Interference ◽  
A Current ◽  
Line Interference

This paper presents a power line interference (PLI) reduction technique with a current-reused current-feedback instrumentation amplifier (CFIA) for electrocardiogram (ECG) recording. In a portable two-electrode ECG monitoring application, the presence of undesired PLI may severely corrupt the quality of ECG recording. Since PLI can be over a few volts, the input signal including the ECG signal can exceed the supply or ground level by an electrostatic discharge (ESD) diode in input/output (I/O) pad. To prevent this problem, this paper presents a continuous-time input common-mode current feedback loop that can limit displacement current from a capacitive coupling between the human body and a power line. The continuous-time input common-mode current feedback loop can clamp an input common-mode voltage to the saturation region of the input transistor of the current-reused CFIA. After the clamping procedure, the clamped input signal is amplified by the current-reused CFIA. The proposed circuit was designed using a 0.18-μm bipolar-complementary metal semiconductor–double-diffused metal oxide semiconductor (BCDMOS) process with an active area of 1.8 mm2. The total power consumption is 18 μW with 1.8 V. The input-referred noise and noise efficiency factor (NEF) of the current-reused CFIA is 2.68 μVRMS and 4.28 with 107 Hz, respectively.

scholarly journals Wide input range, fully-differential indirect current feedback instrumentation amplifier for self-x sensory systems / Symmetrischer Instrumentierungsverstärker mit indirekter Stromgegenkopplung und hoher Eingangsignalspanne für integrierte Sensorsysteme mit Self-x-Eigenschaften

2019 ◽  
Vol 86 (s1) ◽  
pp. 62-66
Author(s):  
Senan Alraho ◽  
Andreas König
Keyword(s):  
Negative Feedback ◽  
High Speed ◽  
Harmonic Distortion ◽  
Instrumentation Amplifier ◽  
Design Tools ◽  
Sensor Signal ◽  
Current Feedback ◽  
Fully Differential ◽  
Feedback Network ◽  
Input Range

AbstractThis paper research presents the design of wide input range indirect current feedback-instrumentation amplifier (CFIA). In order to extend the input range without sacrificing the amplifier performance, the negative feedback is applied to the source coupled differential pairs inputs. The feedback network and the biasing current can be programmed to work at different values to meet different signal conditions or to self-correct the drift in the amplifier properties. The simulated input range Vin; P-P=1.6 V with total harmonic distortion of 0.93 % at 5 MHz frequency. Thus the proposed CFIA is very suitable to read the high speed and high common mode range TMR differential voltage sensor signal. The circuit is implemented using the CMOS 0.35 μm technology from Austriamicrosystems (AMS) and by using Cadence Virtuoso design tools.

scholarly journals Reconfigurable Wide Input Range, Fully-Differential Indirect Current-Feedback Instrumentation Amplifier with Digital Offset Calibration for Self-X Measurement Systems

2020 ◽  
Vol 87 (s1) ◽  
pp. s85-s90
Author(s):  
Senan Alraho ◽  
Qummar Zaman ◽  
Andreas König
Keyword(s):  
Intelligent Systems ◽  
Cmos Technology ◽  
Instrumentation Amplifier ◽  
Current Feedback ◽  
Sensor Interface ◽  
Measurement Systems ◽  
Fully Differential ◽  
Programmable Circuit ◽  
Input Range ◽  
Circuit Configuration

AbstractThis manuscript presents an implementation of the configurable indirect current-feedback instrumentation amplifier (CFIA) for sensor interface readout circuit. Configuration is achieved by designing digital weighted scalable arrays for some selected elements to serve as tuning knobs controlled by the evolutionary optimization algorithm. This scheme resulting in a programmable circuit for different aspects to support self-x functionality. The robustness and flexibility of the proposed circuit fit to the demands of measurement and sensory systems in industry 4.0 and other intelligent systems applications. The circuit is designed by Cadence tools using ams 0.35 μm CMOS technology.

Low-cost Indirect Measurement Methods for Self-x Integrated Sensory Electronics for Industry 4.0

2020 ◽  
Vol 87 (s1) ◽  
pp. s79-s84
Author(s):  
Qummar Zaman ◽  
Senan Alraho ◽  
Andreas König
Keyword(s):  
Industry 4.0 ◽  
Degrees Of Freedom ◽  
Performance Metrics ◽  
Low Cost ◽  
Indirect Measurement ◽  
Measurement Methods ◽  
Instrumentation Amplifier ◽  
Performance Parameters ◽  
Current Feedback ◽  
Indirect Measurements

AbstractThe conventional method for testing the performance of reconfigurable sensory electronics of industry 4.0 relies on the direct measurement methods. This approach gives higher accuracy but at the price of extremely high testing cost and does not utilize the new degrees of freedom for measurement methods enabled by industry 4.0. In order to reduce the test cost and use available resources more efficiently, a primary approach, called indirect measurements or alternative testing has been proposed using a non-intrusive sensor. Its basic principle consists in using the indirect measurements, in order to estimate the sensory electronics performance parameters without measuring directly. The non-intrusive property of the proposed method offers better performance of the sensing electronics and virtually applicable to any sensing electronics. Efficiency is evaluated in terms of model accuracy by using six different classical metrics. It uses an indirect current-feedback instrumentation amplifier (InAmp) as a test vehicle to evaluate the performance parameters of the circuit. The device is implemented using CMOS 0.35 μm technology. The achieved maximum value of average expected error metrics is 0.24, and the lowest value of correlation performance metrics is 0.91, which represent an excellent efficiency of InAmp performance predictor.

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.

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