External charger for an implantable medical device for determining position and optimizing power transmission using resonant frequency as determined from at least one sense coil

摘要

A charging system for an Implantable Medical Device (IMD) is disclosed having a charging coil and one or more sense coils. The charging coil and one or more sense coils are preferably housed in a charging coil assembly coupled to an electronics module by a cable. The charging coil is preferably a wire winding, while the one or more sense coils are concentric with the charging coil and preferably formed in one or more traces of a circuit board. One or more voltages induced on the one or more sense coils can be used to determine the resonant frequency of the charging coil/IMD coupled system. The determined resonant frequency can then be used to determine the position of the charging coil relative to the IMD. The magnetic field produced from the charging coil may also be driven at the resonant frequency to optimize power transfer to the IMD.