Miniaturising wireless power supplies for active implantable devices

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dc.contributor.advisor McCormick, D en
dc.contributor.advisor Budgett, D en Gallichan, Robert en 2017-03-20T20:23:55Z en 2017 en
dc.identifier.uri en
dc.description.abstract Active implantable devices have had a large impact on a range of medical conditions. However, their use has remained limited to a small niche of applications. A challenge limiting their prevalence is miniaturising the device to an unobtrusive and implantable size. Active implants could greatly improve the treatment of medical conditions such as Hydrocephalus. This condition occurs when excess fluid is produced within the brain and leads to increased intracranial pressure. An implantable pressure monitor combined with an active pump or valve would be a large improvement over the current treatment as it could evaluate the pressure within the skull and control fluid volume within the brain. Due to the space constraints and power requirements of this application, batteries alone were not a viable method for powering the implant. Consequently, a wireless power supply solution has been proposed. This thesis coverers the development of a miniaturised integrated circuit for the implant’s rectification and power flow control features. Evaluation of secondary pickup topologies resulted in the parallel topology being chosen as it gave practical coil designs with a low number of turns for the required output powers and load impedances. Multiple rectifier topologies were investigated, and an active diode synchronous rectifier was found to be the most efficient option. Shorting control was used for over-voltage protection and power flow control. In combination with a parallel tuned pickup, shorting control resulted in increased efficiency with increased coupling and greater power transfer with decreased coupling. Furthermore, shorting control could effectively protect the circuitry from large couplings without dissipating excessive power. An integrated circuit 1.29 by 2.12 including an active diode synchronous rectifier and shorting control was designed and fabricated. The rectifier had an efficiency greater than 85% from 30 to 600 . The wireless power management integrated circuit was included in a prototype biopotential telemeter with similar power requirements to a hydrocephalus monitor. A micropump was included and powered from the integrated circuit. This research has demonstrated an efficient wireless power transfer system that is robust to variations in coupling, extremely small in size and capable of supplying the required power for a smart shunt. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA99264957405002091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri en
dc.rights.uri en
dc.title Miniaturising wireless power supplies for active implantable devices en
dc.type Thesis en Bioengineering en The University of Auckland en Doctoral en PhD en
dc.rights.holder Copyright: The author en
dc.rights.accessrights en
pubs.elements-id 617838 en Bioengineering Institute en
pubs.record-created-at-source-date 2017-03-21 en

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