Design of a Programmable Passive SoC for Biomedical Applications Using RFID ISO 15693/NFC5 Interface

Low power, low cost inductively powered passive biotelemetry system involving fully customized RFID/NFC interface base SoC has gained popularity in the last decades. However, most of the SoCs developed are application specific and lacks either on-chip computational or sensor readout capability. In this paper, we present design details of a programmable passive SoC in compliance with ISO 15693/NFC5 standard for biomedical applications. The integrated system consists of a 32-bit microcontroller, a sensor readout circuit, a 12-bit SAR type ADC, 16 kB RAM, 16 kB ROM and other digital peripherals. The design is implemented in a 0.18 μ m CMOS technology and used a die area of 1.52 mm × 3.24 mm. The simulated maximum power consumption of the analog block is 592 μ W. The number of external components required by the SoC is limited to an external memory device, sensors, antenna and some passive components. The external memory device contains the application specific firmware. Based on the application, the firmware can be modified accordingly. The SoC design is suitable for medical implants to measure physiological parameters like temperature, pressure or ECG. As an application example, the authors have proposed a bioimplant to measure arterial blood pressure for patients suffering from Peripheral Artery Disease (PAD)

An Ultra-Low-Power RFID/NFC Frontend IC Using 0.18 μm CMOS Technology for Passive Tag Applications

Battery-less passive sensor tags based on RFID or NFC technology have achieved much popularity in recent times. Passive tags are widely used for various applications like inventory control or in biotelemetry. In this paper, we present a new RFID/NFC frontend IC (integrated circuit) for 13.56 MHz passive tag applications. The design of the frontend IC is compatible with the standard ISO 15693/NFC 5. The paper discusses the analog design part in details with a brief overview of the digital interface and some of the critical measured parameters. A novel approach is adopted for the demodulator design, to demodulate the 10% ASK (amplitude shift keying) signal. The demodulator circuit consists of a comparator designed with a preset offset voltage. The comparator circuit design is discussed in detail. The power consumption of the bandgap reference circuit is used as the load for the envelope detection of the ASK modulated signal. The sub-threshold operation and low-supply-voltage are used extensively in the analog design—to keep the power consumption low. The IC was fabricated using 0.18 μ m CMOS technology in a die area of 1.5 mm × 1.5 mm and an effective area of 0.7 m m 2 . The minimum supply voltage desired is 1.2 V, for which the total power consumption is 107 μ W. The analog part of the design consumes only 36 μ W, which is low in comparison to other contemporary passive tags ICs. Eventually, a passive tag is developed using the frontend IC, a microcontroller, a temperature and a pressure sensor. A smart NFC device is used to readout the sensor data from the tag employing an Android-based application software. The measurement results demonstrate the full passive operational capability. The IC is suitable for low-power and low-cost industrial or biomedical battery-less sensor applications. A figure-of-merit (FOM) is proposed in this paper which is taken as a reference for comparison with other related state-of-the-art researches

Tiedonkäsittelyn tehokkuus aivoissa

Brains are capable of processing information with remarkable efficiency under constraints set by the limited supply of physical resources such as the amount of space and the availability of metabolic energy. Natural selection has optimised the structure and function of brain networks using simple design rules similar to those found in man-made electronic and information systems. This study presents findings concerning a number of general principles of brain design governing the evolution and organisation of neural information processing. The rule of minimising wiring in neuronal networks is one such principle operating on multiple levels of brain organisation. Both individual components and larger brain architectural units are seen to feature characteristics of near-optimal wiring. Miniaturisation of neuronal components conserves space but raises problems about noise in signalling. Small-world organisation of anatomical and functional networks is widely employed in the brain, contributing to high global efficiency at low cost. Metabolic costs severely constrain signal traffic in the human brain, necessitating the use of energy-efficient sparse neural representations. Extensive evidence is presented of anatomical and physiological optimisations facilitating efficient information processing in brain networks. Limitations of current experimental techniques are discussed, with a view on possible future avenues of research.Aivojen tiedonkäsittely on huomattavan tehokasta vallitsevien fysikaalisten rajoitteiden puitteissa, jotka liittyvät muun muassa tilan ja metabolisen energian käyttöön keskushermostossa. Luonnonvalinta pyrkii optimoimaan aivoissa toimivien rakenteellisten ja toiminnallisten verkostojen toiminnan yksinkertaisten sääntöjen pohjalta. Nämä säännöt ovat monesti huomattavan samankaltaisia kuin ihmisen suunnittelemissa elektronisissa laitteissa ja tietoverkoissa. Tämä tutkielma esittelee joukon aivojen tiedonkäsittelyn evolutiivista historiaa, kehitystä ja toimintaa ohjaavia yleisiä suunnittelun periaatteita sekä niihin liittyviä tutkimustuloksia. Keskushermoston rakenteeseen laajalti vaikuttava kaapeloinnin minimoinnin periaate on eräs tällainen sääntö, joka vaikuttaa sekä yksittäisten hermosolujen että kokonaisten aivoalueiden rakenteeseen ja sijoitteluun. Yksittäisten hermosolujen pienentäminen säästää tilaa, mutta vaikeuttaa viestintää kasvattamalla satunnaisen aktiviteetin eli kohinan määrää hermosoluissa. Sekä aivojen rakenteellisissa että toiminnallisissa verkostoissa havaitaan monin niin kutsuttu pieni maailma tyyppinen rakenne, joka tuottaa tehokkaan verkostorakenteen verrattain pienillä biologisilla kustannuksilla. Hermoviestinnän metaboliset kustannukset puolestaan rajoittavat hermoimpulssien määrää ja luovat evolutiivisen paineen muodostaa tehokkaita neuraalisia representaatioita. Esitelty kirjallisuus tarjoaa runsaasti todisteita aivojen tiedonkäsittelyn rakenteellisesta ja toiminnallisesta tehokkuudesta. Lopuksi käsitellään nykyisten tutkimusmetodien rajoituksia ja avoimeksi jääviä kysymyksiä

Ultra low power wearable sleep diagnostic systems

Sleep disorders are studied using sleep study systems called Polysomnography that records several biophysical parameters during sleep. However, these are bulky and are typically located in a medical facility where patient monitoring is costly and quite inefficient. Home-based portable systems solve these problems to an extent but they record only a minimal number of channels due to limited battery life. To surmount this, wearable sleep system are desired which need to be unobtrusive and have long battery life. In this thesis, a novel sleep system architecture is presented that enables the design of an ultra low power sleep diagnostic system. This architecture is capable of extending the recording time to 120 hours in a wearable system which is an order of magnitude improvement over commercial wearable systems that record for about 12 hours. This architecture has in effect reduced the average power consumption of 5-6 mW per channel to less than 500 uW per channel. This has been achieved by eliminating sampled data architecture, reducing the wireless transmission rate and by moving the sleep scoring to the sensors. Further, ultra low power instrumentation amplifiers have been designed to operate in weak inversion region to support this architecture. A 40 dB chopper-stabilised low power instrumentation amplifiers to process EEG were designed and tested to operate from 1.0 V consuming just 3.1 uW for peak mode operation with DC servo loop. A 50 dB non-EEG amplifier continuous-time bandpass amplifier with a consumption of 400 nW was also fabricated and tested. Both the amplifiers achieved a high CMRR and impedance that are critical for wearable systems. Combining these amplifiers with the novel architecture enables the design of an ultra low power sleep recording system. This reduces the size of the battery required and hence enables a truly wearable system.Open Acces

Resource efficient on-node spike sorting

Current implantable brain-machine interfaces are recording multi-neuron activity by utilising multi-channel, multi-electrode micro-electrodes. With the rapid increase in recording capability has come more stringent constraints on implantable system power consumption and size. This is even more so with the increasing demand for wireless systems to increase the number of channels being monitored whilst overcoming the communication bottleneck (in transmitting raw data) via transcutaneous bio-telemetries. For systems observing unit activity, real-time spike sorting within an implantable device offers a unique solution to this problem. However, achieving such data compression prior to transmission via an on-node spike sorting system has several challenges. The inherent complexity of the spike sorting problem arising from various factors (such as signal variability, local field potentials, background and multi-unit activity) have required computationally intensive algorithms (e.g. PCA, wavelet transform, superparamagnetic clustering). Hence spike sorting systems have traditionally been implemented off-line, usually run on work-stations. Owing to their complexity and not-so-well scalability, these algorithms cannot be simply transformed into a resource efficient hardware. On the contrary, although there have been several attempts in implantable hardware, an implementation to match comparable accuracy to off-line within the required power and area requirements for future BMIs have yet to be proposed. Within this context, this research aims to fill in the gaps in the design towards a resource efficient implantable real-time spike sorter which achieves performance comparable to off-line methods. The research covered in this thesis target: 1) Identifying and quantifying the trade-offs on subsequent signal processing performance and hardware resource utilisation of the parameters associated with analogue-front-end. Following the development of a behavioural model of the analogue-front-end and an optimisation tool, the sensitivity of the spike sorting accuracy to different front-end parameters are quantified. 2) Identifying and quantifying the trade-offs associated with a two-stage hybrid solution to realising real-time on-node spike sorting. Initial part of the work focuses from the perspective of template matching only, while the second part of the work considers these parameters from the point of whole system including detection, sorting, and off-line training (template building). A set of minimum requirements are established which ensure robust, accurate and resource efficient operation. 3) Developing new feature extraction and spike sorting algorithms towards highly scalable systems. Based on waveform dynamics of the observed action potentials, a derivative based feature extraction and a spike sorting algorithm are proposed. These are compared with most commonly used methods of spike sorting under varying noise levels using realistic datasets to confirm their merits. The latter is implemented and demonstrated in real-time through an MCU based platform.Open Acces

De animais a máquinas : humanos tecnicamente melhores nos imaginários de futuro da convergência tecnológica

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Sociais, Departamento de Sociologia, 2020.O tema desta investigação é discutir os imaginários sociais de ciência e tecnologia que emergem a partir da área da neuroengenharia, em sua relação com a Convergência Tecnológica de quatro disciplinas: Nanotecnologia, Biotecnologia, tecnologias da Informação e tecnologias Cognitivas - neurociências- (CT-NBIC). Estas áreas desenvolvem-se e são articuladas por meio de discursos que ressaltam o aprimoramento das capacidades físicas e cognitivas dos seres humanos, com o intuito de construir uma sociedade melhor por meio do progresso científico e tecnológico, nos limites das agendas de pesquisa e desenvolvimento (P&D). Objetivos: Os objetivos nesse cenário, são discutir as implicações éticas, econômicas, políticas e sociais deste modelo de sistema sociotécnico. Nos referimos, tanto as aplicações tecnológicas, quanto as consequências das mesmas na formação dos imaginários sociais, que tipo de relações se estabelecem e como são criadas dentro desse contexto. Conclusão: Concluímos na busca por refletir criticamente sobre as propostas de aprimoramento humano mediado pela tecnologia, que surgem enquanto parte da agenda da Convergência Tecnológica NBIC. No entanto, as propostas de melhoramento humano vão muito além de uma agenda de investigação. Há todo um quadro de referências filosóficas e políticas que defendem o aprimoramento da espécie, vertentes estas que se aliam a movimentos trans-humanistas e pós- humanistas, posições que são ao mesmo tempo éticas, políticas e econômicas. A partir de nossa análise, entendemos que ciência, tecnologia e política estão articuladas, em coprodução, em relação às expectativas de futuros que são esperados ou desejados. Ainda assim, acreditamos que há um espaço de diálogo possível, a partir do qual buscamos abrir propostas para o debate público sobre questões de ciência e tecnologia relacionadas ao aprimoramento da espécie humana.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The subject of this research is to discuss the social imaginaries of science and technology that emerge from the area of neuroengineering in relation with the Technological Convergence of four disciplines: Nanotechnology, Biotechnology, Information technologies and Cognitive technologies -neurosciences- (CT-NBIC). These areas are developed and articulated through discourses that emphasize the enhancement of human physical and cognitive capacities, the intuition it is to build a better society, through the scientific and technological progress, at the limits of the research and development (R&D) agendas. Objectives: The objective in this scenery, is to discuss the ethic, economic, politic and social implications of this model of sociotechnical system. We refer about the technological applications and the consequences of them in the formation of social imaginaries as well as the kind of social relations that are created and established in this context. Conclusion: We conclude looking for critical reflections about the proposals of human enhancement mediated by the technology. That appear as a part of the NBIC technologies agenda. Even so, the proposals of human enhancement go beyond boundaries that an investigation agenda. There is a frame of philosophical and political references that defend the enhancement of the human beings. These currents that ally to the transhumanism and posthumanism movements, positions that are ethic, politic and economic at the same time. From our analysis, we understand that science, technology and politics are articulated, are in co-production, regarding the expected and desired futures. Even so, we believe that there is a space of possible dialog, from which we look to open proposals for the public discussion on questions of science and technology related to enhancement of human beings

Signal Enhancement Strategies in Classical Electrochemiluminescence Techniques for Modern Biosensing

With the ascent of IT, and since Ashton has invented the term Internet of Things (IoT) in 1999, this future idea of connected machines that can do tasks and perform decision-control cycles without human input has become more and more attractive and is today an established future scenario. Obviously, in an IoT, “sensors for everything” are one crucial corner stone of its existence and Analytical chemistry can and must deliver them. While many challenges towards a functioning IoT remain, we are on the verge of its beginning. This can be also seen with “Analytics 4.0” in research and on the market, tending to more IT-connected, portable, easier-controllable and integrated solutions. The entrance of mobility in the health sector or Point-of-Care (POC) diagnostics trends are alike influencing biosensing. Whether in mobile solutions or lab- and clinical environments, versatile, powerful and easy-to-adapt detection strategies like Electrochemiluminescence (ECL) are an attractive option. The ECL molecules [Ru(bpy)3]2+ and luminol represent the most prominent and most abundantly investigated luminophores for ECL since Bard’s accomplishment to make ECL a well-known technique. Because both are also two of the most efficient ECL emitters that can be well-handled in bioanalysis, and are available on the market, they are still today frequently used in research and also commercial applications. To cope with current benchmarks of sensitive detection, however a combination with a certain signal enhancement strategy is recommended. Several different routes can here be employed and one option is dendrimers. PAMAM dendrimers can function as ECL coreactant in [Ru(bpy)3]2+-ECL via their amino groups and at the same time expose primary amino groups as possible bioconjugation elements. Exploring this multi-functionality of the dendrimers was investigated here. This was done on a model system employing PAMAM dendrimers with [Ru(bpy)3]2+-ECL together with biotin/streptavidin as biorecognition element and analyte, respectively. The dendrimer’s bi-functionality was successfully proven and a joint-role of a biorecognition element and a possible reporter function suggests an optimum application in homogeneous assays. A different toolset for ECL signal enhancement is offered by liposomes. Numerous signaling molecules can be encapsulated inside the inner cavity of these synthetic vesicles, while they provide protection from the environment and connection-functionality to probes via lipids and surface groups on the outside. That application was here explored, together with a newly synthesized luminol derivative obtained by a simple synthesis route from commercial starting materials and exhibiting a four times increased ECL efficiency versus standard luminol. That was necessary as a liposome enhancement was denied for the standard luminol through its poor aqueous solubility. The new m-carboxy luminol considerably improved this feature which allowed its own encapsulation in liposomes. The superior signal generation with this dual system was proven in a model sandwich hybridization assay which yielded a 150-times better detection performance than the equal fluorescence-based assay while being almost zero affected through matrices like serum, soil or river water. As such the good performance of luminol ECL together with liposomes for highly sensitive detection applications was demonstrated. A further necessary element with liposomal amplification, are surfactants to set free the signaling molecules. However, this case depicts only one example of a multitude of applications of surfactants in bioassays and biochemical methods. Hence, surfactants are commonly present solution constituents which also have to be considered in general with ECL because they can influence the ECL signals positively or negatively. This was further investigated for luminol ECL by exploring the effect of 13 different surfactants on the luminol ECL efficiency on four different electrode materials. A deeper understanding of the distinct effects was obtained by looking into ECL emission behavior, electrochemical effects, the surfaces and Chemiluminescence effects. After all, the revelation of a complicated mechanism that involves many contributing factors and as such directs signal quenching or enhancement is an important finding for assay design. In this way, the selection of a suitable surfactant is possible to exploit maximum reachable signal efficiencies. A combination of signal enhancement tools like a better ECL molecule derivative, dendrimers, liposomes or surfactants has proven to boost the ECL performance considerably. A further means of signal enhancement is offered via miniaturization, which also makes the detection method better suited towards common application as liquid handling and easier automation are on hand. This can be used for single ECL assays or combinations of different ECL reagents in one system for multi-detection. Different strategies for the miniaturization of an ECL readout-capable system were investigated, taking requirements for [Ru(bpy)3]2+ and luminol as ECL reporters into account. This includes materials, electrochemical demands and simple design. Here, ITO electrodes – while advantageous for luminol ECL could not convince with their performance in [Ru(bpy)3]2+-ECL. Alternatively, laser scribed graphene electrodes have shown to be promising candidates for a future miniaturized system encompassing both, luminol and [Ru(bpy)3]2+ as ECL systems. Ultimately, the different signal amplifying strategies, investigated in this work that can be applied standalone or combined, offer a great toolset for state-of-the-art ECL detection applications in research and also for possible commercial applications

Ultra-low-power circuits and systems for wearable and implantable medical devices

Thesis (Ph. D.)--Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 219-231).Advances in circuits, sensors, and energy storage elements have opened up many new possibilities in the health industry. In the area of wearable devices, the miniaturization of electronics has spurred the rapid development of wearable vital signs, activity, and fitness monitors. Maximizing the time between battery recharge places stringent requirements on power consumption by the device. For implantable devices, the situation is exacerbated by the fact that energy storage capacity is limited by volume constraints, and frequent battery replacement via surgery is undesirable. In this case, the design of energy-efficient circuits and systems becomes even more crucial. This thesis explores the design of energy-efficient circuits and systems for two medical applications. The first half of the thesis focuses on the design and implementation of an ultra-low-power, mixed-signal front-end for a wearable ECG monitor in a 0.18pm CMOS process. A mixed-signal architecture together with analog circuit optimizations enable ultra-low-voltage operation at 0.6V which provides power savings through voltage scaling, and ensures compatibility with state-of-the-art DSPs. The fully-integrated front-end consumes just 2.9[mu]W, which is two orders of magnitude lower than commercially available parts. The second half of this thesis focuses on ultra-low-power system design and energy-efficient neural stimulation for a proof-of-concept fully-implantable cochlear implant. First, implantable acoustic sensing is demonstrated by sensing the motion of a human cadaveric middle ear with a piezoelectric sensor. Second, alternate energy-efficient electrical stimulation waveforms are investigated to reduce neural stimulation power when compared to the conventional rectangular waveform. The energy-optimal waveform is analyzed using a computational nerve fiber model, and validated with in-vivo ECAP recordings in the auditory nerve of two cats and with psychophysical tests in two human cochlear implant users. Preliminary human subject testing shows that charge and energy savings of 20-30% and 15-35% respectively are possible with alternative waveforms. A system-on-chip comprising the sensor interface, reconfigurable sound processor, and arbitrary-waveform neural stimulator is implemented in a 0.18[mu]m high-voltage CMOS process to demonstrate the feasibility of this system. The sensor interface and sound processor consume just 12[mu]W of power, representing just 2% of the overall system power which is dominated by stimulation. As a result, the energy savings from using alternative stimulation waveforms transfer directly to the system.by Marcus Yip.Ph.D