CURRENT LEAKAGE DETECTION FOR A MEDICAL IMPLANT

• US 20100274319A1
• Filed: 04/28/2010
• Published: 10/28/2010
• Est. Priority Date: 04/28/2009
• Status: Abandoned Application

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Meskens, Werner
• Application Number:
  US12/769,389
• Publication Number:
  US 20100274319A1
• Time in Patent Office: Days
• US Class Current: 607/57
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: A61N 1/37 Monitoring; Protecting

Abstract

Current leakage detection techniques in an implantable medical device are disclosed. In these techniques, a core surrounds conductors carrying current to and from an implanted medical device. A secondary winding on the core picks up imbalances between the current flows on the conductors traveling through the core. An imbalance is detected if the current on the secondary winding results in a specified threshold being exceeded. Corrective action may then be taken if a current imbalance is detected.

Claims

1. An implantable medical device comprising:

at least one electronic circuit;

a current imbalance detector comprising;

a core surrounding at least a portion of one or more electrical conductors connected to the at least one electronic circuit;

a winding on the core; and

a detection circuit connected to the winding and configured to provide a signal indicative of whether there is an imbalance in current conducted by the one more electrical conductors; and

a hermetically sealed housing that houses said at least one electronic circuit and said current imbalance detector.

2. The implantable medical device of claim 1, wherein the detection circuit comprises:

a resistive element connected to the winding, wherein a voltage across the resistive element provides the signal indicative of whether there is a current imbalance.

3. The implantable medical device of claim 2, wherein the voltage across the resistive element is proportional to a common mode current through the one or more electrical conductors and a number of turns of the winding on the core.

4. The implantable medical device of claim 2, wherein the resistive element comprises a resistor connected to the winding, and wherein the resistor is connected to an input of an amplifier.

5. The implantable medical device of claim 2, wherein the resistive element comprises an intrinsic resistance of an input of an amplifier.

6. The implantable medical device of claim 1, wherein the detection circuit comprises a signal detector configured to provide an output based on a sensed signal from the winding.

7. The implantable medical device of claim 1, wherein the detection circuit comprises an amplifier configured to amplify the current imbalance.

9. The implantable medical device of claim 1, further comprising:

a leakage control unit configured to receive the signal indicative of whether there is a current imbalance and perform an action based on the received signal.

10. The implantable medical device of claim 9, wherein the leakage control unit is configured to take a corrective action if the signal indicates that there is a current imbalance;

wherein the corrective action includes at least one of disconnecting one or more electrical components of the medical device, disconnecting a power supply;

directing a compensation current to be applied;

adjusting a duty cycle; and

/or transmitting an alarm message.

11. The implantable medical device of claim 1, further comprising:

an RF balun.

12. The implantable medical device of claim 1, wherein the implantable medical device is an implantable component of a cochlear implant system.

13. The implantable medical device of claim 1, wherein the implantable medical device is an active implantable medical device.

14. The implantable medical device of claim 13, wherein the active implantable medical device contains an implantable component configured to give electrical stimulation and/or electro-mechanical stimulation.

15. The implantable medical device of claim 1, wherein the implantable medical device is an implantable component for a system selected from the set of an functional electrical stimulation system, an electro-mechanical stimulation system, an auditory brainstem system, a spinal cord stimulator system, a heart stimulation system, a drug dispensing system, and a bone growth stimulation system.

16. The implantable medical device of claim 1, wherein the core is a ferrite core.

17. The implantable medical device of claim 1, wherein the signal indicative of whether there is a current imbalance is a signal that has a specified logical value if a current imbalance is detected, the implantable medical device further comprising:

a transmission device configured to transfer the signal to an external device.

18. The implantable medical device of claim 1, wherein the signal indicative of whether there is a current imbalance is a signal representative of a value of any current imbalance on the one or more electrical conductors, the implantable medical device further comprising:

a transmission device configured to transfer the signal to an external device.

8. The implantable medical device of 1, further comprising a comparator configured to provide an output indicative of whether the output of the current imbalance detector exceeds a threshold.

19. A method for use in an implantable medical device having at least one electronic circuit, the method comprising:

obtaining a signal representative of a sensed signal from a winding on a core, wherein the core surrounds at least a portion of one or more electronic conductors connected to the at least one electronic circuit of the implantable medical device;

determining if the sensed signal indicates an imbalance in current conducted by the one or more electrical conductors; and

performing a corrective action if a current imbalance is detected exceeding a threshold.

20. The method of claim 19, wherein determining if the sensed signal indicates an imbalance in current comprises:

amplifying the sensed signal; and

comparing said amplified sensed signal with the threshold.

21. The method of claim 19, wherein the corrective action includes at least one of:

disconnecting or disabling one or more electrical components of the medical device;

disconnecting or disabling a power supply;

directing a compensation current to be applied;

adjusting a duty cycle; and

transmitting an alarm message.

22. The method of claim 19, wherein the implantable medical device is a component of a cochlear implant system.

23. The method of claim 19, wherein the implantable medical device is an active implantable medical device.

24. The method of claim 19, wherein the implantable medical device contains an implantable component giving electrical stimulation and/or electro-mechanical stimulation.

25. The method of claim 19, wherein the active implantable medical device is at least one of an function electrical stimulation system, an electro-mechanical stimulation system, an auditory brainstem system, a spinal cord stimulator system, a heart stimulation system, a drug dispensing system, and a bone growth stimulation system.

26. A system for use in an implantable medical device having at least one electronic circuit, the system comprising:

means for obtaining a signal representative of a sensed signal from a winding on a core, wherein the core surrounds at least a portion of one or more electronic conductors connected to the at least one electronic circuit of the implantable medical device;

means for determining if the sensed signal indicates an imbalance in current conducted by the one or more electrical conductors; and

means for performing a corrective action if a current imbalance is detected exceeding a threshold.