Inductively rechargeable external energy source, charger and system for a transcutaneous inductive charger for an implantable medical device
A mechanism for transferring energy from an external power source to an implantable medical device is disclosed. An antenna is positioned in proximity of the implantable medical device. The position of a core of the antenna is adjusted relative to the implantable medical device while the antenna is maintained substantially stationary. A frequency of transmission of a power source is adjusted, and the antenna is driven at the adjusted frequency to transfer energy transcutaneously to the implantable medical device. In one embodiment, the frequency of transmission is selected based on an amplitude of a signal in the antenna.
1. A system, comprising:
an implantable medical device for providing a therapy to a patient, the implantable medical device having a secondary coil and a rechargeable power source;
an external charging system, comprising:
a primary coil having a major plane and an axis orthogonal to the major plane;
a power source adapted to generate a signal in the primary coil that is of a selectable frequency; and
a moveable core laterally movable in order to reposition the core with respect to the axis of the primary coil to focus magnetic flux generated by the signal in the primary coil.
2. The system of claim 1 wherein the selectable frequency is chosen to optimize an amplitude of the signal.
3. The system of claim 2 wherein efficiency of energy transfer between the external charging system and the implantable medical device is increased.
4. The system of claim 1 wherein the generated signals are in a frequency range of between eight and twelve kilohertz.
5. The system of claim 4 wherein the generated signals are approximately nine (9) kiloHertz unloaded.
6. The system of claim 1 wherein the movable core is selectably laterally movable with respect to the axis of the primary coil while the primary coil is in a selected position with respect to the secondary coil.
7. The system of claim 6 wherein the movable core is selectably laterally movable with respect to the axis of the primary coil to focus magnetic flux generated by the signal in the primary coil to the secondary coil.
8. The system of claim 1 wherein the movable core is rotatably positionable within the primary coil.
9. The system of claim 8 wherein the core is rotatably movable at any selected one of multiple predetermined positions.
10. The system of claim 9 wherein the movable core comprises an upper planar portion and a smaller lower portion.
11. The system of claim 1 wherein the primary coil further comprises a core cup assembly adapted to support the movable core.
12. The system of claim 1 wherein the power source further comprises a circuit to generate the signal at a frequency at which an amplitude of the signal is optimized.
13. The system of claim 1 wherein the primary coil and the power source are contained within a same housing.