A Wide-Band Efficient Inductive Transdennal Power and Data Link with Coupling Insensitive Gain
TL;DR: A new method of desensitizing the gain of an inductive link to the mutual coupling of its inductors when the coupling varies due to geometrical misalignments is described.
Abstract: This paper describes a new method of desensitizing the gain of an inductive link to the mutual coupling of its inductors. When the coupling varies due to geometrical misalignments [1] this design method guarantees good efficiency and a large bandwidth. The mathematics for four link combinations are presented, and examples of the link efficiency and bandwidth for one of the combinations are shown and discussed.
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08 Nov 2004
TL;DR: This paper describes the development of a high-density electronic interface to the central nervous system that permits the long-term monitoring of neural activity in vivo as well as the insertion of electronic signals into neural networks at the cellular level.
Abstract: This paper describes the development of a high-density electronic interface to the central nervous system. Silicon micromachined electrode arrays now permit the long-term monitoring of neural activity in vivo as well as the insertion of electronic signals into neural networks at the cellular level. Efforts to understand and engineer the biology of the implant/tissue interface are also underway. These electrode arrays are facilitating significant advances in our understanding of the nervous system, and merged with on-chip circuitry, signal processing, microfluidics, and wireless interfaces, they are forming the basis for a family of neural prostheses for the possible treatment of disorders such as blindness, deafness, paralysis, severe epilepsy, and Parkinson's disease.
677Â citations
Cites background from "A Wide-Band Efficient Inductive Tra..."
...Their performance over decades, consistent with prosthetic applications, is still unknown, and additional dielectric overcoats such as diamond are being explored....
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01 Jan 1996
TL;DR: In this paper, a geometric approach for the enhancement of the coupling coefficient between two magnetically coupled coils is presented, where the turns of the coils are not concentrated at the Circumferences, but distributed across the diameters.
Abstract: This paper presents a geometric approach for the enhancement of the coupling coefficient between two magnetically coupled coils. It is demonstrated that the coupling coefficient can be considerably enhanced, if the turns of the coils are not concentrated at the Circumferences, but distributed across the diameters. For analysis, each of the two coils is assumed to be composed of concentric circular loops. The experimental results are in very good agreement with the theoretical results.
401Â citations
TL;DR: It is demonstrated that the coupling coefficient can be considerably enhanced, if the turns of the coils are not concentrated at the circumferences, but distributed across the diameters.
Abstract: This paper presents a geometric approach for the enhancement of the coupling coefficient between two magnetically coupled coils. It is demonstrated that the coupling coefficient can be considerably enhanced, if the turns of the coils are not concentrated at the circumferences, but distributed across the diameters. For analysis, each of the two coils is assumed to be composed of concentric circular loops. The experimental results are in very good agreement with the theoretical results.
401Â citations
TL;DR: In this paper, the effects of coil misalignment and geometry are addressed in a single mathematical expression for inductively coupled wireless power transfer, and a novel analytical power transfer efficiency model is presented.
Abstract: A novel analytical model of inductively coupled wireless power transfer is presented. For the first time, the effects of coil misalignment and geometry are addressed in a single mathematical expression. In the applications envisaged, such as radio frequency identification (RFID) and biomedical implants, the receiving coil is normally significantly smaller than the transmitting coil. Formulas are derived for the magnetic field at the receiving coil when it is laterally and angularly misaligned from the transmitting coil. Incorporating this magnetic field solution with an equivalent circuit for the inductive link allows us to introduce a power transfer formula that combines coil characteristics and misalignment factors. The coil geometries considered are spiral and short solenoid structures which are currently popular in the RFID and biomedical domains. The novel analytical power transfer efficiency expressions introduced in this study allow the optimization of coil geometry for maximum power transfer and misalignment tolerance. The experimental results show close correlation with the theoretical predictions. This analytic technique can be widely applied to inductive wireless power transfer links without the limitations imposed by numerical methods.
355Â citations
Cites methods from "A Wide-Band Efficient Inductive Tra..."
...As demonstrated by Galbraith in [9], there are four combinations of series and parallel tuned TX and RX circuits, which can be equally well represented by the equivalent circuit of Fig....
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TL;DR: A new approach is presented for transmitting RF power and signal via an inductive link that optimizes the power efficiency of the overall transmission scheme comprising the power amplifier plus the inductive links.
Abstract: A new approach is presented for transmitting RF power and signal via an inductive link. Such an approach optimizes the power efficiency of the overall transmission scheme comprising the power amplifier plus the inductive link. Power amplification is based on the single ended class E concept. The power amplification stage is self-oscillating, and thus the oscillation frequency is influenced by the coupling of the coils. The resulting operating frequency offset yields improved power transmission performance of the circuit, since the oscillation frequency tracks the absolute transmission efficiency maximum. A detailed analysis is given. Realization of the approach requires a minimal number of circuit components. Experimental and theoretical results are in good agreement. >
352Â citations
References
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TL;DR: A detailed theoretical analysis of misalignment effects in RF coil systems, including lateral and angular misalignments, is presented.
Abstract: Radio-frequency (RF) coils are used extensively in the design of implantable devices for transdermal power and data transmission. The practical issues of coil misalignments and configurations have not been investigated, and this paper presents a detailed theoretical analysis of misalignment effects in RF coil systems, including lateral and angular misalignments. Formulas are derived for the mutual inductance and, whenever possible, simplified upper bounds and lower bounds of the coupling coefficient are provided. A design procedure is established to maximize coil coupling for a given configuration, and a companion paper [1] discusses a circuit design technique to reduce the effects of misalignment on transmission efficiency.
263Â citations
TL;DR: A transcutaneous signal transmission system for an auditory prosthesis has been designed that can be used for several other stimulation purposes needing accurate control of stimulation parameters.
Abstract: A stable transcutaneous transmission of power and signal via two coupled coils with minimized dependence on the relative spacing of external and implanted coil is possible by employing "critical coupling" between implanted and external circuits. Optimizing coil geometries and preventing the RF output amplifier from saturating is necessary to approximately maintain critical coupling despite placement tolerances within a reasonable range. Based on these considerations a transcutaneous signal transmission system for an auditory prosthesis has been designed. This transmission system can also be used for several other stimulation purposes needing accurate control of stimulation parameters.
150Â citations
TL;DR: Values of mutual inductance between two circular conductors lying in parallel planes have been computed and their relevance to the design of radio-frequency coupled implant systems is mentioned.
Abstract: Values of mutual inductance between two circular conductors lying in parallel planes have been computed. The results are presented in graphical form and their relevance to the design of radio-frequency coupled implant systems is mentioned.
97Â citations
TL;DR: Major improvements over previous systems include controlled introduction of anisotropic flexing properties in the electrode array to facilitate insertion and optimal contact orientation, enlarged and stabilised contact surface area and the development of a new connector technology which combines high density, high reliability, biocompatibility and ease of operation during surgery.
Abstract: The technical and safety requirements for intracochlear electrical stimulation to restore hearing in the profoundly deaf are reviewed. A system has been implanted in human subjects which comprises a 16-contact flexible electrode array, radio receiver/stimulator and surgical disconnect which permits changing from percutaneous cable to transcutaneous telemetry. The design, fabrication, and mechanical and electrical testing of each of the components are discussed in detail. Major improvements over previous systems include controlled introduction of anisotropic flexing properties in the electrode array to facilitate insertion and optimal contact orientation, enlarged and stabilised contact surface area and the development of a new connector technology which combines high density, high reliability, biocompatibility and ease of operation during surgery.
87Â citations
TL;DR: A novel low-power low-component count CMOS charge-redistribution digital-to-analog (D/A) demultiplexer which produces a high resolution neuro-compatible charge output and an extended missing pulse code is developed which assures higher reliability and protection against excess and erroneous stimulations.
Abstract: Describes an implantable multielectrode neural stimulator developed for electrical stimulation of the auditory nerves with the aim of producing a sensation of sound in sensory deaf ears. Power and digitally coded amplitude and frequency data are transcutaneously transmitted to the implantable stimulator using an inductively coupled RF link and an ultrasonic link, respectively. A novel low-power low-component count CMOS charge-redistribution digital-to-analog (D/A) demultiplexer which produces a high resolution neuro-compatible charge output is described. An extended missing pulse code is developed which assures higher reliability and protection against excess and erroneous stimulations. An experimental 4-electrode system capable of stimulating up to a 5-kHz rate and consuming less than 10 mW of power is presented.
42Â citations