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Tripathi SK, Hussain S, Kumar R, Sahu S. Design and Analysis of Digitally Tunable Transconductance Amplifier (DTTA) Using CNTFETs. ScientificWorldJournal 2024; 2024:2003437. [PMID: 38818110 PMCID: PMC11139501 DOI: 10.1155/2024/2003437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 04/04/2024] [Accepted: 05/03/2024] [Indexed: 06/01/2024] Open
Abstract
Carbon nanotube-FETs (CNTFETs) have become a potential challenger because of their exceptional electrical properties and compatibility with conventional CMOS technology. The design and study of digitally tunable transconductance amplifiers (DTTAs) using CNTFETs are the main topics of this work. By utilizing the special characteristics of CNTFETs, the suggested DTTA design makes transconductance tunable, providing a versatile method of adjusting amplifier settings without requiring modifications to the hardware architecture. This study provides a complete description of the CNTFET modeling techniques utilized for realistic circuit simulations, along with a detailed analysis of the DTTA based on CNTFETs. The circuit is implemented using a 32 nm CNTFET model and verified results with HSPICE.
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Affiliation(s)
| | | | - Raj Kumar
- Department of ICT, Adani University, Ahmedabad, India
| | - Sourabh Sahu
- Department of ECE, Gyan Ganga Institute of Technology and Sciences, Jabalpur, India
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Wu J, Akinin A, Somayajulu J, Lee MS, Paul A, Lu H, Park Y, Kim SJ, Mercier PP, Cauwenberghs G. A Low-Noise Low-Power 0.001Hz-1kHz Neural Recording System-on-Chip With Sample-Level Duty-Cycling. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2024; 18:263-273. [PMID: 38408002 PMCID: PMC11062612 DOI: 10.1109/tbcas.2024.3368068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Advances in brain-machine interfaces and wearable biomedical sensors for healthcare and human-computer interactions call for precision electrophysiology to resolve a variety of biopotential signals across the body that cover a wide range of frequencies, from the mHz-range electrogastrogram (EGG) to the kHz-range electroneurogram (ENG). Existing integrated wearable solutions for minimally invasive biopotential recordings are limited in detection range and accuracy due to trade-offs in bandwidth, noise, input impedance, and power consumption. This article presents a 16-channel wide-band ultra-low-noise neural recording system-on-chip (SoC) fabricated in 65nm CMOS for chronic use in mobile healthcare settings that spans a bandwidth of 0.001 Hz to 1 kHz through a featured sample-level duty-cycling (SLDC) mode. Each recording channel is implemented by a delta-sigma analog-to-digital converter (ADC) achieving 1.0 μ V rms input-referred noise over 1Hz-1kHz bandwidth with a Noise Efficiency Factor (NEF) of 2.93 in continuous operation mode. In SLDC mode, the power supply is duty-cycled while maintaining consistently low input-referred noise levels at ultra-low frequencies (1.1 μV rms over 0.001Hz-1Hz) and 435 M Ω input impedance. The functionalities of the proposed SoC are validated with two human electrophysiology applications: recording low-amplitude electroencephalogram (EEG) through electrodes fixated on the forehead to monitor brain waves, and ultra-slow-wave electrogastrogram (EGG) through electrodes fixated on the abdomen to monitor digestion.
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Mohammed H, Chen HB, Li Y, Sabor N, Wang JG, Wang G. Meta-Analysis of Pulse Transition Features in Non-Invasive Blood Pressure Estimation Systems: Bridging Physiology and Engineering Perspectives. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2023; 17:1257-1281. [PMID: 38015673 DOI: 10.1109/tbcas.2023.3334960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
The pulse transition features (PTFs), including pulse arrival time (PAT) and pulse transition time (PTT), hold significant importance in estimating non-invasive blood pressure (NIBP). However, the literature showcases considerable variations in terms of PTFs' correlation with blood pressure (BP), accuracy in NIBP estimation, and the comprehension of the relationship between PTFs and BP. This inconsistency is exemplified by the wide-ranging correlations reported across studies investigating the same feature. Furthermore, investigations comparing PAT and PTT have yielded conflicting outcomes. Additionally, PTFs have been derived from various bio-signals, capturing distinct characteristic points like the pulse's foot and peak. To address these inconsistencies, this study meticulously reviews a selection of such research endeavors while aligning them with the biological intricacies of blood pressure and the human cardiovascular system (CVS). Each study underwent evaluation, considering the specific signal acquisition locale and the corresponding recording procedure. Moreover, a comprehensive meta-analysis was conducted, yielding multiple conclusions that could significantly enhance the design and accuracy of NIBP systems. Grounded in these dual aspects, the study systematically examines PTFs in correlation with the specific study conditions and the underlying factors influencing the CVS. This approach serves as a valuable resource for researchers aiming to optimize the design of BP recording experiments, bio-signal acquisition systems, and the fine-tuning of feature engineering methodologies, ultimately advancing PTF-based NIBP estimation.
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Tamilarasan E, Duraisamy GNR, Elangovan MK, Sarasam AST. A 0.8 V, 14.76 nVrms, Multiplexer-Based AFE for Wearable Devices Using 45 nm CMOS Techniques. MICROMACHINES 2023; 14:1816. [PMID: 37893253 PMCID: PMC10609258 DOI: 10.3390/mi14101816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 10/29/2023]
Abstract
Wearable medical devices (WMDs) that continuously monitor health conditions enable people to stay healthy in everyday situations. A wristband is a monitoring format that can measure bioelectric signals. The main part of a wearable device is its analog front end (AFE). Wearables have issues such as low reliability, high power consumption, and large size. A conventional AFE device uses more analog-to-digital converters, amplifiers, and filters for individual electrodes. Our proposed MUX-based AFE design requires fewer components than a conventional AFE device, reducing power consumption and area. It includes a single-ended differential feedback operational transconductance amplifier (OTA) and n-pass MUX-based AFE circuits which are related to the emergence of low power, low area, and low cost AFE-integrated chips that are required for wearable biomedical applications. The proposed 6T n-pass multiplexer measures a gain of -68 dB across a frequency range of 100 kHz with a 136.5 nW power consumption and a delay of 0.07 ns. The design layout area is approximately 9.8 µm2 and uses 45 nm complementary metal oxide semiconductor (CMOS) technology. Additionally, the proposed single-ended differential OTA has an obtained input referred noise of 0.014 µVrms, and a gain of -5.5 dB, while the design layout area is about 2 µm2 and was designed with the help of the Cadence Virtuoso layout design tool.
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Affiliation(s)
- Esther Tamilarasan
- Department of Electronics and Communication, Thigarajar College of Engineering, Madurai 625005, Tamil Nadu, India
| | | | - Muthu Kumaran Elangovan
- Engineering, D.R.B.R. Ambedkar Institute of Technology, Port Blair 744101, Union Territory of Andaman & Nicobar Islands, India;
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Timosina V, Cole T, Lu H, Shu J, Zhou X, Zhang C, Guo J, Kavehei O, Tang SY. A Non-Newtonian liquid metal enabled enhanced electrography. Biosens Bioelectron 2023; 235:115414. [PMID: 37236012 DOI: 10.1016/j.bios.2023.115414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023]
Abstract
Biopotential signals, like electrocardiography (ECG), electromyography (EMG), and electroencephalography (EEG), can help diagnose cardiological, musculoskeletal and neurological disorders. Dry silver/silver chloride (Ag/AgCl) electrodes are commonly used to obtain these signals. While a conductive hydrogel can be added to Ag/AgCl electrodes to improve the contact and adhesion between the electrode and the skin, dry electrodes are prone to movement. Considering that the conductive hydrogel dries over time, the use of these electrodes often creates an imbalanced skin-electrode impedance and a number of sensing issues in the front-end analogue circuit. This issue can be extended to several other electrode types that are commonly in use, in particular, for applications with a need for long-term wearable monitoring such as ambulatory epilepsy monitoring. Liquid metal alloys, such as eutectic gallium indium (EGaIn), can address key critical requirements around consistency and reliability but present challenges on low viscosity and the risk of leakage. To solve these problems, here, we demonstrate the use of a non-eutectic Ga-In alloy as a shear-thinning non-Newtonian fluid to offer superior performance to commercial hydrogel electrodes, dry electrodes, and conventional liquid metals for electrography measurements. This material has high viscosity when still and can flow like a liquid metal when sheared, preventing leakage while allowing the effective fabrication of electrodes. Moreover, the Ga-In alloy not only has good biocompatibility but also offers an outstanding skin-electrode interface, allowing for the long-term acquisition of high-quality biosignals. The presented Ga-In alloy is a superior alternative to conventional electrode materials for real-world electrography or bioimpedance measurement.
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Affiliation(s)
- Veronika Timosina
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Tim Cole
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Hongda Lu
- School of Mechanical, Materials, Mechatronic, and Biomedical Engineering, University of Wollongong, Wollongong, Australia
| | - Jian Shu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, China
| | - Xiangbo Zhou
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, China
| | - Chengchen Zhang
- Graduate School of Biomedical Engineering, University of New South Wales, NSW, 2052, Australia
| | - Jinhong Guo
- The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The College of Laboratory Medicine, Chongqing Medical University, #1 Yixueyuan Road, Yuzhong District, Chongqing, 400016, China
| | - Omid Kavehei
- School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, NSW, 2006, Australia; The University of Sydney Nano Institute, Sydney, NSW, 2006, Australia.
| | - Shi-Yang Tang
- Department of Electronic, Electrical and Systems Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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Ranjandish R, Schmid A. A Review of Microelectronic Systems and Circuit Techniques for Electrical Neural Recording Aimed at Closed-Loop Epilepsy Control. SENSORS (BASEL, SWITZERLAND) 2020; 20:E5716. [PMID: 33050032 PMCID: PMC7583980 DOI: 10.3390/s20195716] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/07/2020] [Accepted: 10/02/2020] [Indexed: 12/21/2022]
Abstract
Closed-loop implantable electronics offer a new trend in therapeutic systems aimed at controlling some neurological diseases such as epilepsy. Seizures are detected and electrical stimulation applied to the brain or groups of nerves. To this aim, the signal recording chain must be very carefully designed so as to operate in low-power and low-latency, while enhancing the probability of correct event detection. This paper reviews the electrical characteristics of the target brain signals pertaining to epilepsy detection. Commercial systems are presented and discussed. Finally, the major blocks of the signal acquisition chain are presented with a focus on the circuit architecture and a careful attention to solutions to issues related to data acquisition from multi-channel arrays of cortical sensors.
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Affiliation(s)
- Reza Ranjandish
- Department of Information Technology and Electrical Engineering, ETH Zürich, CH-8092 Zürich, Switzerland;
| | - Alexandre Schmid
- Institute of Electrical Engineering, EPF Lausanne, CH-1015 Lausanne, Switzerland
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A CMOS Low Pass Filter for SoC Lock-in-Based Measurement Devices. SENSORS 2019; 19:s19235173. [PMID: 31779162 PMCID: PMC6928706 DOI: 10.3390/s19235173] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 11/15/2019] [Accepted: 11/22/2019] [Indexed: 12/23/2022]
Abstract
This paper presents a fully integrated Gm–C low pass filter (LPF) based on a current steering Gm reduction-tuning technique, specifically designed to operate as the output stage of a SoC lock-in amplifier. To validate this proposal, a first-order and a second-order single-ended topology were integrated into a 1.8 V to 0.18 µm CMOS (Complementary Metal-Oxide-Semiconductor) process, showing experimentally a tuneable cutoff frequency that spanned five orders of magnitude, from tens of mHz to kHz, with a constant current consumption (below 3 µA/pole), compact size (<0.0140 mm2/pole), and a dynamic range better than 70 dB. Compared to state-of-the-art solutions, the proposed approach exhibited very competitive performances while simultaneously fully satisfying the demanding requirements of on-chip portable measurement systems in terms of highly efficient area and power. This is of special relevance, taking into account the current trend towards multichannel instruments to process sensor arrays, as the total area and power consumption will be proportional to the number of channels.
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Mandrumaka KK, Noorbasha F. A low power 10 bit SAR ADC with variable threshold technique for biomedical applications. SN APPLIED SCIENCES 2019. [DOI: 10.1007/s42452-019-0940-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Bano S, Narejo GB, Ali SU. 7.2 nW 68 dB DR Fourth Order Self-compensated Low Pass Filter for Portable ECG Application. ADVANCED BIOMEDICAL ENGINEERING 2019. [DOI: 10.14326/abe.8.153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Saleha Bano
- Department of Electronic Engineering, NED University of Engineering & Technology
| | - Ghous Bakhsh Narejo
- Department of Electronic Engineering, NED University of Engineering & Technology
| | - S.M. Usman Ali
- Department of Electronic Engineering, NED University of Engineering & Technology
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Rodrigues EM, Godina R, Cabrita CM, Catalão JP. Experimental low cost reflective type oximeter for wearable health systems. Biomed Signal Process Control 2017. [DOI: 10.1016/j.bspc.2016.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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