Medtronic, Inc.

Erik G Widman

David P Olson

William C Phillips

Jeffrey T Keacher

John W Forsberg

Alex C Toy

Giselle Suraya Figueiredo

Telemetry signal strength is used for positioning a primary recharge coil of a recharging unit at a location proximate to an Implantable Medical Device (IMD) in preparation to recharge a rechargeable power source of the IMD. An antenna of the recharging unit is positioned proximate to the IMD, a telemetry session is initiated between the two devices, and a value indicative of the telemetry signal strength is obtained. Using a known correspondence between telemetry signal strength and recharge coupling efficiency for the IMD/recharging unit pair, the telemetry signal strength value is used to determine whether adequate recharge coupling may be achieved between the pair of devices. If so, a recharge session may be established. Otherwise, the antenna is repositioned and the process is repeated. The correspondence between telemetry signal strength and recharge coupling efficiency for the device pair may be developed empirically or using modeling.

Using telemetry coupling as a surrogate for recharger coupling

An external antenna with a plurality of concentric primary coils recharges an implantable medical device with a secondary coil when the primary coils are placed in proximity of the secondary coil. Selection circuitry determines which of the plurality of concentric primary coils has the most efficient coupling with the secondary coil and drive circuitry drives the selected primary coil with an oscillating current. During a recharge session, selection circuitry periodically checks at least some of the primary coils to determine whether the primary coil with the most efficient connection has changed. An antenna housing may hold the primary coils in a rigid planar relationship with each other or the primary coils may shift with respect to each other, forming a cup-shape around a bulge in the skin created by the implantable medical device.

Concentric primary coils for inductively charging an implantable medical device, external power source and method

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Minneapolis, MN, United States of America

Erik G Widman