External Charger for an Implantable Medical Device For Adjusting Charging Power Based on Determined Position Using at Least One Sense Coil

• US 20170361116A1
• Filed: 06/07/2017
• Published: 12/21/2017
• 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., Larcom, Jonathan, Gupta, Gaurav
• Granted Patent: US 11,471,692 B2
• Time in Patent Office: Days
• 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 27/402 Association of measuring or protective means
• 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 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits

Abstract

A charging system for an Implantable Medical Device (IMD) is disclosed having a charging coil and one or more sense coils 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 sense coils are 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 one or more parameters (magnitude, phase angle, resonant frequency) indicative of the position between the charging coil and the IMD, which position may include the radial offset and possibly also the depth of the charging coil relative to the IMD. Knowing the position, the power of the magnetic field produced by the charging coil can be adjusted to compensate for the position.

Claims

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

a charging coil configured when energized by a drive signal to produce a magnetic field with a power to wirelessly provide energy to the IMD as a coupled system;

a sense coil, wherein the sense coil is configured to be induced by the magnetic field with an induced signal affected by a position of the charging coil with respect to the IMD; and

control circuitry configured to determine from a parameter determinable using the induced signal how to adjust the power of the magnetic field,

wherein the parameter comprises either

a phase angle between the induced signal and the drive signal, or

a resonant frequency of the coupled system.

2. The external charger of claim 1, wherein the control circuitry is configured to determine how to adjust the power by determining a position of the charging coil with respect to the IMD using the parameter, and then determining how to adjust the power using the determined position.

3. The external charger of claim 2, wherein the determined position comprises a radius at which the charging coil is laterally offset with respect to the IMD.

4. The external charger of claim 3, wherein the determined position further comprises a depth between the charging coil and the IMD.

5. The external charger of claim 2, wherein the control circuitry further comprises or has access to a database, wherein the database comprises a plurality of thresholds, wherein the control circuitry is configured to compare the parameter to one of the thresholds to determine the position of the charging coil with respect to the IMD.

6. The external charger of claim 2, wherein the control circuitry further comprises or has access to a database, wherein the database comprises values for the parameter at different radial offsets and depths between the charging coil and the IMD, wherein the control circuitry is configured to compare the parameter to the values to determine the position of the charging coil with respect to the IMD.

7. The external charger of claim 1, wherein the sense coil is concentric with the charging coil.

8. The external charger of claim 1, further comprising an electronics module and a charging coil assembly coupled to the electronics module by a cable,

wherein the charging coil and the sense coil are within the charging coil assembly, and

wherein the control circuitry is within the electronics module.

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

10. The external charger of claim 9, wherein the charging coil comprises a wire winding placed on a side of the circuit board.

11. The external charger of claim 9, wherein the charging coil comprises a wire winding, and wherein the circuit board is placed within the wire winding of the charging coil.

12. The external charger of claim 1, further comprising drive circuitry configured to receive the drive signal and energize the charging coil.

13. The external charger of claim 12, wherein the control circuitry adjusts the power of the magnetic field by adjusting a duty cycle of the drive signal.

14. The external charger of claim 1, wherein the sense coil comprises a circle.

15. The external charger of claim 1, wherein the sense coil comprises two circles of different radii.

16. The external charger of claim 15, wherein the two circles are connected such that such that a current flowing through the two circles will flow in different directions in the two circles.