IMPLANTABLE MEDICAL DEVICE WITH BACKSCATTER SIGNAL BASED COMMUNICATION

• US 20140055088A1
• Filed: 08/23/2012
• Published: 02/27/2014
• Est. Priority Date: 08/23/2012
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: JOSHI, Himanshu
• Granted Patent: US 9,343,923 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/3787 from an external energy source
• 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 50/80 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

Abstract

An implantable medical device is disclosed that includes a charging coil configured to inductively couple to a first external coil to receive a charging signal to charge a charge storage element of the implantable medical device. The implantable medical device also includes a circuit coupled to the charging coil. The circuit includes a circuit component that, in response to the charging signal, generates a backscatter signal. The implantable medical device also includes a communication coil orthogonal to the charging coil and coupled to the circuit component. The communication coil is configured to inductively couple to a second external coil to communicate the backscatter signal to the second external coil.

Claims

1. An implantable medical device comprising:

a charging coil configured to inductively couple to a first external coil to receive a charging signal to charge a charge storage element;

a circuit coupled to the charging coil, the circuit including a circuit component that, in response to the charging signal, generates a backscatter signal; and

a communication coil orthogonal to the charging coil and coupled to the circuit component, the communication coil configured to inductively couple to a second external coil to communicate the backscatter signal to the second external coil.

2. The implantable medical device of claim 1, wherein the circuit component is a non-linear circuit element.

3. The implantable medical device of claim 1, wherein the circuit includes a rectifier and wherein the circuit component includes a diode of the rectifier.

4. The implantable medical device of claim 1, wherein the backscatter signal is at a higher frequency than the charging signal.

5. The implantable medical device of claim 1, further comprising a therapy delivery unit coupled to the charge storage element, the therapy delivery unit configured to deliver therapy to a patient in which the implantable medical device is implanted using power from the charge storage element.

6. The implantable medical device of claim 1, wherein the backscatter signal has a frequency that is approximately three times a frequency of the charging signal.

7. The implantable medical device of claim 1, wherein the backscatter signal has a frequency that is approximately five times a frequency of the charging signal.

8. The implantable medical device of claim 1, wherein the charging coil is formed from a first conductor wound about a core and wherein the communication coil is formed from a second conductor wound about the core.

9. The implantable medical device of claim 8, wherein the second conductor is more lossy than the first conductor.

10. The implantable medical device of claim 1, wherein the backscatter signal is indicative of a charging voltage applied to the charge storage element, the charging voltage responsive to the charging signal.

11. The implantable medical device of claim 1, wherein the charge storage element is a rechargeable battery.

12. A method comprising:

receiving a charging signal at a charging coil of an implantable medical device by inductively coupling the charging coil to a first external coil of a charging device;

rectifying the charging signal and applying the rectified charging signal to a charge storage element of the implantable medical device;

applying a backscatter signal to a communication coil of the implantable medical device, wherein the backscatter signal is generated responsive to the charging signal being applied to a component of the implantable medical device and wherein the communication coil is orthogonal to the charging coil; and

sending the backscatter signal to an external device by inductively coupling the communication coil to a second external coil of an external device to communicate the backscatter signal to the second external coil.

13. The method of claim 12, wherein the second external coil is orthogonal to the first external coil and the charging coil.

14. The method of claim 13, wherein the external device is included in the charging device.

15. The method of claim 12, wherein the communication coil is orthogonal to the first external coil.

16. A charging device comprising:

a first charging coil configured to couple to a second charging coil of an implantable medical device, wherein the first charging coil is adapted to communicate a charging signal to the second charging coil to charge a charge storage element of the implantable medical device; and

a sensing coil that is orthogonal to the first charging coil, the sensing coil configured to detect a backscatter signal from a communication coil of the implantable medical device.

17. The charging device of claim 16, wherein a component of the implantable medical device generates the backscatter signal responsive to the charging signal.

18. The charging device of claim 16, further comprising a control unit configured to perform a frequency sweep of the charging signal to identify, based on the backscatter signal, a particular frequency associated with an improved charging efficiency relative to other frequencies of the charging signal.

19. The charging device of claim 16, further comprising a control unit configured to cease application of the charging signal in response to processing of the backscatter signal.

20. A method comprising:

applying a charging signal to a first charging coil of a charging device;

communicating the charging signal to a second charging coil of an implantable medical device by inductively coupling the second charging coil and the first charging coil, wherein the implantable medical device includes a charge storage element that is charged using the charging signal; and

detecting, at a sensing coil, a backscatter signal from a communication coil of the implantable medical device, wherein the sensing coil is orthogonal to the first charging coil.

21. The method of claim 20, further comprising estimating charging efficiency of the charging signal based on the backscatter signal.

22. The method of claim 21, further comprising, after estimating the charging efficiency, adjusting a frequency of the charging signal.

23. The method of claim 20, further comprising performing a frequency sweep of the charging signal to identify, based on the backscatter signal, a particular frequency associated with an improved charging efficiency relative to other frequencies of the charging signal.

24. The method of claim 20, further comprising ceasing application of the charging signal in response to processing of the backscatter signal.

25. The method of claim 20, wherein a component of the implantable medical device generates the backscatter signal responsive to the charging signal.