External charger for an implantable medical device having alignment and centering capabilities

• US 10,576,294 B2
• Filed: 01/21/2019
• Issued: 03/03/2020
• Est. Priority Date: 06/15/2016
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Aghassian, Daniel, Stouffer, Thomas W.
• Primary Examiner(s): Diao, M Baye
• Application Number:
  US16/252,982
• Publication Number:
  US 20190151668A1
• Time in Patent Office: 407 Days
• Field of Search: 320108
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61M 2205/8243 by induction
• CPC Class Codes: A61N 1/0534 Electrodes for deep brain stimulation
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H01F 27/2804 Printed windings
• CPC Class Codes: H01F 27/2823 Wires H01F27/2866 takes precedence
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

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 whether the charging coil is (i) centered, (ii) not centered but not misaligned, or (iii) misaligned, with respect to the IMD being charged, which three conditions sequentially comprise lower coupling between the charging coil and the IMD. A charging algorithm is also disclosed that control charging dependent on these conditions.

Claims

1. An external charger for wirelessly providing energy to an implantable medical device (IMD), comprising:

a charging coil; and

controller circuitry configured to implement an algorithm, wherein the algorithm comprises the steps of;

(a) determining whether the charging coil is centered with respect to the IMD, wherein centered comprises a condition in which the coupling between the charging coil and the IMD is higher than a first coupling value;

(b) once the charging coil is centered with respect to the IMD, proceeding to step (c);

(c) producing for a time a first magnetic field from the charging coil to wirelessly provide energy to the IMD;

(d) after the time, determining whether the charging coil is misaligned with respect to the IMD, wherein misaligned comprises a condition in which the coupling between the charging coil and the IMD is less than or equal to a second coupling value less than the first coupling value;

(e) if the charging coil is not misaligned with respect to the IMD, returning to step (c); and

(f) if the charging coil is misaligned with respect to the IMD, returning to step (a).

2. The external charger of claim 1, further comprising producing a test magnetic field from the charging coil in steps (a) and (d), wherein determining whether the charging coil is centered with respect to the IMD in step (a) occurs during the test magnetic field, and wherein determining at least whether the charging coil is misaligned with respect to the IMD in step (d) occurs during the test magnetic field.

3. The external charger of claim 2, further comprising at least one sense coil concentric with the charging coil,

wherein each at least one sense coil is configured to be induced by the test magnetic field with an induced signal, and

wherein the determining steps in steps (a) and (d) comprise assessing the at least one induced signal.

4. The external charger of claim 2, further comprising a single sense coil concentric with the charging coil,

wherein the sense coil is configured to be induced by the test magnetic field with an induced signal, and

wherein the determining steps in steps (a) and (d) comprise assessing the induced signal.

5. The external charger of claim 2, further comprising a first sense coil and a second sense coil both concentric with the charging coil,

wherein the first sense coil is configured to be induced by the test magnetic field with a first induced signal,

wherein the second sense coil is configured to be induced by the test magnetic field with a second induced signal,

wherein the determining step of step (a) comprises assessing the first induced signal, and

wherein the determining step of step (d) comprises assessing the second induced signal.

6. The external charger of claim 5, wherein the first sense coil comprises a first radius, and wherein the second sense coil comprises a second radius larger than the first radius.

7. The external charger of claim 2, wherein the test magnetic field is of constant power, and wherein a power of the first magnetic field can vary.

8. The external charger of claim 2, wherein step (d) further comprises determining during the test magnetic field whether the charging coil is centered with respect to the IMD.

9. The external charger of claim 8, wherein if the charging coil is not centered but is not misaligned with respect to the IMD, returning to step (c).

10. The external charger of claim 1, further comprising a circuit board, wherein the at least one sense coil is formed in one or more traces in the circuit board.

11. The external charger of claim 10, wherein the charging coil comprises a wire winding.

12. The external charger of claim 1, further comprising a user interface, wherein if the charging coil is not centered in step (a), the controller circuitry is configured to issue a first alert via the user interface.

13. The external charger of claim 12, wherein once the charging coil is centered with respect to the IMD in step (b), the controller circuitry is configured in step (c) to cease the first alert or issue a second alert via the user interface.

14. The external charger of claim 13, wherein if the charging coil is misaligned with respect to the IMD in step (f), the controller circuitry is configured to issue the first alert.

15. The external charger of claim 1, wherein step (d) further comprises determining whether the charging coil is centered with respect to the IMD.

16. The external charger of claim 15, wherein if the charging coil is not centered but is not misaligned with respect to the IMD, returning to step (c).

17. The external charger of claim 16, further comprising a user interface,

wherein if the charging coil is not centered in step (a), issuing a first alert via the user interface, and

wherein once the charging coil is centered with respect to the IMD in step (b), issuing a second alert via the user interface.

18. The external charger of claim 17, wherein if the charging coil is not centered but is not misaligned with respect to the IMD in step (e), issuing a third alert via the user interface.

19. The external charger of claim 18, wherein if the charging coil is misaligned with respect to the IMD in step (f), issuing the first alert.