A Partial-Current-Steering Biphasic Stimulation Driver for Vestibular Prostheses

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Neuromodulation: present and emerging methods.

Neuromodulation has wide ranging potential applications in replacing impaired neural function (prosthetics), as a novel form of medical treatment (therapy), and as a tool for investigating neurons and neural function (research). Voltage and current controlled electrical neural stimulation (ENS) are methods that have already been widely applied in both neuroscience and clinical practice for neuroprosthetics. However, there are numerous alternative methods of stimulating or inhibiting neurons. This paper reviews the state-of-the-art in ENS as well as alternative neuromodulation techniques-presenting the operational concepts, technical implementation and limitations-in order to inform system design choices

A charge-metering method for voltage-mode neural stimulation

AbstractElectrical neural stimulation is the technique used to modulate neural activity by inducing an instantaneous charge imbalance. This is typically achieved by injecting a constant current and controlling the stimulation time. However, constant voltage stimulation is found to be more energy-efficient although it is challenging to control the amount of charge delivered. This paper presents a novel, fully integrated circuit for facilitating charge-metering in constant voltage stimulation. It utilises two complementary stimulation paths. Each path includes a small capacitor, a comparator and a counter. They form a mixed-signal integrator that integrates the stimulation current onto the capacitor while monitoring its voltage against a threshold using the comparator. The pulses from the comparator are used to increment the counter and reset the capacitor. Therefore, by knowing the value of the capacitor, threshold voltage and output of the counter, the quantity of charge delivered can be calculated. The system has been fabricated in 0.18μm CMOS technology, occupying a total active area of 339μm×110μm. Experimental results were taken using: (1) a resistor–capacitor EEI model and (2) platinum electrodes with ringer solution. The viability of this method in recruiting action potentials has been demonstrated using a cuff electrode with Xenopus sciatic nerve. For a 10nC target charge delivery, the results of (2) show a charge delivery error of 3.4% and a typical residual charge of 77.19pC without passive charge recycling. The total power consumption is 45μW. The performance is comparable with other publications. Therefore, the proposed stimulation method can be used as a new approach for neural stimulation

Scientific Advances in STEM: From Professor to Students

This book collects the publications of the special Topic Scientific advances in STEM: from Professor to students. The aim is to contribute to the advancement of the Science and Engineering fields and their impact on the industrial sector, which requires a multidisciplinary approach. University generates and transmits knowledge to serve society. Social demands continuously evolve, mainly because of cultural, scientific, and technological development. Researchers must contextualize the subjects they investigate to their application to the local industry and community organizations, frequently using a multidisciplinary point of view, to enhance the progress in a wide variety of fields (aeronautics, automotive, biomedical, electrical and renewable energy, communications, environmental, electronic components, etc.). Most investigations in the fields of science and engineering require the work of multidisciplinary teams, representing a stockpile of research projects in different stages (final year projects, master’s or doctoral studies). In this context, this Topic offers a framework for integrating interdisciplinary research, drawing together experimental and theoretical contributions in a wide variety of fields

Electronics for Sensors

The aim of this Special Issue is to explore new advanced solutions in electronic systems and interfaces to be employed in sensors, describing best practices, implementations, and applications. The selected papers in particular concern photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs) interfaces and applications, techniques for monitoring radiation levels, electronics for biomedical applications, design and applications of time-to-digital converters, interfaces for image sensors, and general-purpose theory and topologies for electronic interfaces

Volume 3 – Conference

We are pleased to present the conference proceedings for the 12th edition of the International Fluid Power Conference (IFK). The IFK is one of the world’s most significant scientific conferences on fluid power control technology and systems. It offers a common platform for the presentation and discussion of trends and innovations to manufacturers, users and scientists. The Chair of Fluid-Mechatronic Systems at the TU Dresden is organizing and hosting the IFK for the sixth time. Supporting hosts are the Fluid Power Association of the German Engineering Federation (VDMA), Dresdner Verein zur Förderung der Fluidtechnik e. V. (DVF) and GWT-TUD GmbH. The organization and the conference location alternates every two years between the Chair of Fluid-Mechatronic Systems in Dresden and the Institute for Fluid Power Drives and Systems in Aachen. The symposium on the first day is dedicated to presentations focused on methodology and fundamental research. The two following conference days offer a wide variety of application and technology orientated papers about the latest state of the art in fluid power. It is this combination that makes the IFK a unique and excellent forum for the exchange of academic research and industrial application experience. A simultaneously ongoing exhibition offers the possibility to get product information and to have individual talks with manufacturers. The theme of the 12th IFK is “Fluid Power – Future Technology”, covering topics that enable the development of 5G-ready, cost-efficient and demand-driven structures, as well as individual decentralized drives. Another topic is the real-time data exchange that allows the application of numerous predictive maintenance strategies, which will significantly increase the availability of fluid power systems and their elements and ensure their improved lifetime performance. We create an atmosphere for casual exchange by offering a vast frame and cultural program. This includes a get-together, a conference banquet, laboratory festivities and some physical activities such as jogging in Dresden’s old town.:Group 8: Pneumatics Group 9 | 11: Mobile applications Group 10: Special domains Group 12: Novel system architectures Group 13 | 15: Actuators & sensors Group 14: Safety & reliabilit

Charge Pumps for Implantable Microstimulators in Low and High-Voltage Technologies

RÉSUMÉ L'objectif principal de cette thèse est de concevoir et mettre en œuvre une pompe de charge qui peut produire suffisamment de tension afin de l’implémenter à un système de prothèse visuelle, conçue par le laboratoire PolyStim neurotechnologies. Il a été constaté que l'une des parties les plus consommatrices d'énergie de l'ensemble du système de prothèse visuelle est la pompe de charge. En raison de la nature variable du tissu nerveux et de l'interface d’électrode, la tension nécessaire par stimuler le tissu nerveux est très élevé et consomme extrêmement d’énergie. En outre, afin de fournir du courant biphasique aux électrodes il faut produire des tensions positives et négatives. La génération de tension négative est très difficile, surtout dans les technologies à faible tension compte tenu des limites de la technologie. Le premier objectif du projet est de générer la haute tension nécessaire qui va consommer une faible puissance statique. La technologie de haute tension a été utilisée dans le but d’atteindre cet objectif. Le deuxième objectif est de générer la tension requise dans la technologie de basse tension et ainsi surmonter les limites de la technologie. Dans les deux cas, une attention particulière a été portée afin que personne ne latch-up apparaît pour le cycle négatif. L'architecture de la conception proposée a été présentée dans cette thèse. La pompe de charge a été conçu et mis en oeuvre à la fois dans la technologie CMOS 0,8 μm offert par TELEDYNE DALSA et technologie 0,13 μm CMOS offert par IBM. En raison de la tension requise, 0,8 μm technologie a été utilisée pour atteindre la sortie et conçu pour minimiser la consommation de puissance statique. La même architecture a été mise en oeuvre en technologie 0,13 μm pour enquêter sur la tension de sortie obtenue avec une faible consommation électrique. Les deux puces ont été testées en laboratoire PolyStim. Les résultats testés ont montré une variation moyenne très faible de déviation inférieure à 5% par rapport au résultat de simulation. Pour la conception en 0,8 µm, nous avons été en mesure d'obtenir plus de 25 V avec une consommation électrique très faible d’énergie statique de 3,846 mW et une charge d'entraînement maximum de 2 mA avec un maximum d'efficacité de 84,2%. Pour le même processus en 0,13 µm, les resultats ont été plus que 20V, 0,913 mW, 500 µA, et 85,2% respectivement.----------ABSTRACT The main objective of the thesis is to design and implement a charge pump that can produce enough voltage required to be implemented to the visual prosthesis system, designed by the PolyStim Neurotechnologies laboratory. It has been found that one of the most power consuming parts of the whole visual prosthesis system is the charge pump. Due to the variable nature of the nerve tissue and electrode interface, the required voltage of stimulating the nerve tissue is very high and thus extremely power consuming. Also, in order to provide biphasic current to the electrodes, there is a requirement of generating both positive and negative voltages. Generating negative voltage is very hard especially in low voltage technologies considering the technology limitations. The first objective of the project is to generate required high voltage that will consume low static power. High voltage technology has been used to achieve the goal. The second objective is to generate the required voltage in low voltage technology overcoming the technology limitations. In both cases, special care has been taken so that no latch-up occurs for the negative cycle. Architecture of the proposed design has been presented in this thesis. The charge pump has been designed and implemented in both 0.8 µm CMOS technology offered by TELEDYNE DALSA and 0.13 µm CMOS technology offered by IBM. Because of the required voltage, 0.8 µm technology has been used to achieve the output and designed to minimize the static power consumption. The same architecture has been implemented in 0.13 µm technology to investigate the achievable output voltage with low power consumption. Both the chips have been tested in polyStim laboratory. The tested results have shown very low variation of less than 5% average deflection from the simulation output. For the design in 0.8 µm, we have been able to get more than 25 V output with very low static power consumption of 3.846 mW and maximum drive load of 2 mA with maximum efficiency of 84.2%. For the same design in 0.13 µm, the outputs were more than 20V, 0.913 mW, 500 µA, and 85.2% respectively

Génération de stimuli efficaces en énergie pour la microstimulation électrique intracorticale

RÉSUMÉ Ce mémoire a comme objectif principal la mise en oeuvre de circuits dédiés à l’amélioration de l’efficacité de la stimulation électrique de tissus situés au niveau du cortex visuel primaire. Le stimulateur proposé permet la génération de nouveaux stimuli flexibles de forme exponentielle et demi-sinusoïdale dans l’optique de réduire la consommation de puissance globale de l’implant. En plus d’être potentiellement plus efficaces que les stimulations rectangulaires standard pour exciter les tissus, ces formes d’impulsions permettraient également de réduire la concentration d’ions toxiques relâchés par les électrodes. Le second objectif de ce projet est de permettre la stimulation à pleine échelle, soit au moins 150 µA, à travers l’interface microélectrode-tissus qui est caractérisée par une impédance élevée. Un étage de sortie à haute-tension a donc également été réalisé afin de générer des tensions d’alimentation d’environ ±9 V et d’augmenter ainsi l’excursion de tension des stimuli tout en étant entièrement intégré. Une architecture comportant deux circuits intégrés indépendants est proposée dans ce mémoire. Le générateur de stimuli est implémenté dans la technologie CMOS 0,18-µ m 1,8V/3,3V de TSMC afin de limiter sa consommation de puissance. Pour ce qui est de l’étage de sortie, il est intégré à l’aide du procédé C08E CMOS/DMOS 0,8-µ m 5V/20V de DALSA Semiconductors, technologie supportant les niveaux de tension requis.Les deux puces ainsi fabriquées ont été testées. L’intensité des stimuli rectangulaires couvre une plage de 1,6 à 167,2 µ A des erreurs de non-linéarité différentielle et intégrale de 0,10 et 0,16 LSB respectivement. Les impulsions exponentielles ont une plage dynamique de 34,36 dB pour une erreur de ±0,5 dB par rapport à la fonction théorique. La consommation de puissance du générateur de stimuli atteint en moyenne 29,1 µW en mode rectangulaire et de 28,5 à 88,3 µ W en mode exponentiel. Les résultats obtenus pour la demi-sinusoïde proviennent de simulations. En moyenne, 80,2 % de la durée des impulsions demi-sinusoïdales a une erreur inférieure à ±1 % par rapport à la fonction idéale. Le générateur de stimuli complet consomme de 46,7 à 199,1 µW en mode demi-sinusoïdal. En ce qui a trait à l’étage de sortie, des tensions de 8,95 et -8,46 V sont générées avec succès, permettant à l’excursion de tension d’atteindre 13,6 V à travers une charge de 100 kΩ.----------ABSTRACT This master thesis’ main objective is the implementation of circuits dedicated to electrical stimulation efficiency enhancement for tissues in the primary visual cortex. The proposed stimulator allows novel stimuli waveform generation such as flexible exponential and half-sine pulses in order to reduce the implant’s global power consumption. In addition of being potentially more efficient to excite neural tissues than standard rectangular pulse-based stimulations, these waveforms should also reduce toxic ions concentration released by the electrodes. Moreover, this project’s second objective is to allow full-scale stimulation, i.e., at least 150 µA, through high-impedance microelectrode-tissue interfaces. A high-voltage output stage has also been realized to generate ±9 V voltage supplies to increase the voltage swing while being fully-integrated. An architecture composed of two independent integrated circuits has been proposed. The stimuli generator is implemented in TSMC CMOS 0.18-µ m 1.8V/3.3V technology to limit its power consumption. On the other hand, the output stage is integrated in C08E CMOS/DMOS 0.8- µm 5V/20V process from DALSA Semiconductors as this technology supports the required voltage levels.These two fabricated chips were tested. Rectangular stimuli intensity varies from 1.6 to 167.2 µA with differential and integral nonlinearities of 0.10 and 0.16 LSB, respectively. Exponential pulses show a dynamic range of 34.36 dB for an error of ±0.5 dB with the theoretical waveform. The stimuli generator’s power consumption reaches an average of 29.1 µW in rectangular mode and from 28.5 to 88.3 µW in exponential mode. Half-sine results are obtained from simulations. An average of 80.2 % of half-sine pulse duration has an error lower than ±1 % with the ideal sine function. The whole stimuli generator consumes from 46.7 to 199.1 µW in half-sine mode. For the output stage, voltages of 8.95 and -8.46 V are successfully generated, allowing the output voltage compliance to reach 13.6 V through a 100 kΩ load. However, this chip dissipates 51.37 mW when operating normally