Multi-axis coil for implantable medical device

Patent metadata

Field	Value
Publication number	US-11813470-B2
Application number	US-202017027013-A
Country	US
Kind code	B2
Filing date	Sep 21, 2020
Priority date	Jun 28, 2018
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

Systems, devices and methods allow inductive recharging of a power source located within or coupled to an implantable medical device while the device is implanted in a patient. The implantable devices in some examples include a multi-axis antenna having a plurality of coil windings arranged orthogonal to one another. The multi-axis antenna configured to generate at least a minimum level of induced current for recharging a power source of the implanted medical device regardless of the orientation of a direction of a magnetic field imposed on the multi-axis antenna relative to an orientation of the implanted medical device and the multi-axis antenna for a given energy level of the imposed magnetic field.

First claim

What is claimed is:

1. A method comprising:
receiving, at a multi-axis antenna of a medical device internal to a patient, a magnetic field having a magnetic field direction, the magnetic field generated by at least one recharging coil, wherein the magnetic field induces one or more electrical currents in one or more of a plurality of coils forming the multi-axis antenna, the plurality of coils comprising a first coil having a first coil axis of orientation, a second coil having a second coil axis of orientation, and a third coil having a third coil axis of orientation;
rectifying the one or more electrical currents induced in the one or more plurality of coils;
summing the one or more rectified electrical currents to form a recharging current;
applying the recharging current to a power source of the medical device to recharge the power source; and
switching, with a switching device, the summed one or more electrical currents between the power source and a shunt device, the shunt device comprising an electrically resistive load.

2. The method of claim 1 , further comprising matching, with one or more capacitors coupled in parallel with the one or more of the plurality of coils, a frequency of the magnetic field generated by the at least one recharging coil with a resonant frequency of a tank circuit formed by the one or more capacitors coupled in parallel with the one or more of the plurality of coils.

3. The method of claim 1 , further comprising preventing, with one or more diodes coupled to the one or more of the plurality of coils, the one or more electrical currents induced in the one or more plurality of coils from being backward driven into another of the plurality of coils.

4. The method of claim 1 , further comprising sensing, with sensing circuitry, each of the one or more electrical currents induced in the one or more plurality of coils.

5. The method of claim 1 , wherein each of the first coil, the second coil, and the third coil encircle a portion of a ferrite core, and wherein the third coil encircles at least a portion of the first coil and the second coil, and wherein the second coil encircles at least a portion of the first coil.

6. The method of claim 1 , further comprising:
determining that the summed one or more electrical currents induced into the plurality of coils is not to be applied to the power source; and
responsive to determining the summed one or more electrical currents is not to be applied to the power source, shunting, with the shunt device coupled in parallel with the power source, the summed one or more electrical currents.

7. The method of claim 1 , wherein the medical device is implanted within the patient.

8. The method of claim 1 , wherein the first axis, the second axis, and the third axis are orthogonal.

9. A medical device configured to be within a patient, the medical device comprising:
a rechargeable power source configured to provide electrical power to the medical device;
a multi-axis antenna comprising a plurality of coils encircling a ferrite core, the multi-axis antenna configured to generate a recharging current from one or more electrical currents induced into one or more of the plurality of coils when an externally generated magnetic field having a magnetic field direction is imposed onto the multi-axis antenna,
wherein the plurality of coils comprises a first coil having a first coil axis of orientation and formed from first electrically conductive winding, a second coil having a second coil axis of orientation and formed from a second electrically conductive winding, and a third coil having a third coil axis of orientation and formed from a third electrically conductive winding;
one or more diodes coupled to one or more of the plurality of coils and configured to prevent the one or more electrical currents induced into the one or more of the plurality of coils from being backward driven into another of the one or more of the plurality of coils;
recharging circuitry coupled to the multi-axis antenna and to the rechargeable power source, the recharging circuitry configured to direct a sum of the one or more electrical currents induced in one or more of the plurality of coils into the rechargeable power source; and
a switching device, coupled to the recharging circuitry and the multi-axis antenna, the switching device configured to switch the sum of the one or more electrical currents between the rechargeable power source and a shunt device, the shunt device comprising an electrically resistive load.

10. The medical device of claim 9 , further comprising one or more capacitors coupled in parallel with the one or more of the plurality of coils to match a frequency of the magnetic field generated externally with a resonant frequency of a tank circuit formed by the one or more capacitors coupled in parallel with the one or more of the plurality of coils.

11. The medical device of claim 9 , wherein the one or more diodes are configured to rectify the one or more electrical currents induced in the one or more plurality of coils.

12. The medical device of claim 9 , further comprising sensing circuitry coupled to the recharging circuitry and the multi-axis antenna that senses the one or more electrical currents induced in the one or more plurality of coils.

13. The medical device of claim 9 , wherein each of the first coil, the second coil, and the third coil encircle a portion of the ferrite core, and wherein the third coil encircles at least a portion of the first coil and the second coil, and wherein the second coil encircles at least a portion of the first coil.

14. The medical device of claim 9 , wherein the first axis, the second axis, and the third axis are orthogonal.

15. A recharging system for recharging a rechargeable power source located in a medical device internal to a patient, the recharging system comprising:
an electrical power source;
at least one recharging coil coupled to the electrical power source and configured to generate a magnetic field having a magnetic field direction and frequency when electrically energized by the electrical power source;
a multi-axis antenna located in the medical device, the multi-axis antenna comprising a plurality of coils configured to generate a recharging current when the magnetic field generated by the at least one recharging coil is imposed onto the multi-axis antenna,
wherein the plurality of coils comprises a first coil having a first coil axis of orientation, a second coil having a second coil axis of orientation, and a third coil having a third coil axis of orientation;
one or more capacitors coupled in parallel with one or more of the plurality of coils, where the one or more capacitors are configured to have a resonant frequency that matches the magnetic field frequency applied by the at least one recharging coil;
a common node to the plurality of coils, the common node configured to sum one or more currents induced into one or more of the first coil, the second coil, and the third coil to generate the recharging current; and
a switching device coupled to the multi-axis antenna, the rechargeable power source of the medical device, and a shunt device, the switching device configured to be controlled by recharging circuitry to couple the recharging current to the rechargeable power source to recharge the electrical energy stored in the rechargeable power source, or to couple the recharging current to the shunt device, and the shunt device comprising an electrically resistive load.

16. The system of claim 15 , further comprising one or more diodes coupled to one or more of the pluralit

Assignees

• Medtronic Inc

Inventors

• Iyer Rajesh V
• Munns Gordon O
• Nielsen Christian S
• Schmidt Craig L
• Young Paul B

Classifications

• H02J7/70

  characterised by the mechanical construction · CPC title

• A61N1/3756

  Casings with electrodes thereon, e.g. leadless stimulators · CPC title

• A61N1/37512

  Pacemakers · CPC title

• A61N1/3787 Primary

  from an external energy source · CPC title

• A61N1/37229

  Shape or location of the implanted or external antenna · CPC title