IMPLANTABLE MEDICAL DEVICE WITH HALL SENSOR

• US 20090157146A1
• Filed: 12/08/2008
• Published: 06/18/2009
• Est. Priority Date: 12/12/2007
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Muttonen, Angela M., Linder, William J.
• Granted Patent: US 8,121,678 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing

Abstract

An operating mode of an implantable medical device can be selected using at least one of a current or a voltage provided in response to a magnetic field sensed using a Hall effect sensor.

Claims

1. An apparatus comprising:

an implantable medical device including;

a Hall effect sensor configured to sense a magnetic field and to provide at least one of a current or a voltage in response to the magnetic field; and

a processor electrically coupled to the Hall effect sensor, the processor configured to select an operating mode of the implantable medical device using at least one of the current or the voltage provided by the Hall effect sensor.

2. The apparatus of claim 1, wherein the Hall effect sensor is configured to adjust at least one of the current or the voltage provided in response to the magnetic field;

and

wherein the processor is configured to select the operating mode of the implantable medical device in response to the adjustment of the at least one of the current or the voltage.

3. The apparatus of claim 1, wherein the processor is configured to select the operating mode of the implantable medical device from a list including at least one of:

(1) a first operating mode when a magnitude of the magnetic field is below a specified first threshold;

(2) a second operating mode when the magnitude of the magnetic field exceeds or equals the specified first threshold over a specified first duration;

or

(3) a third operating mode when the magnitude of the magnetic field further exceeds or equals a specified second threshold over a specified second duration.

4. The apparatus of claim 3, wherein the first operating mode includes an ambulatory operating mode;

wherein the second operating mode includes a battery status test mode wherein the implantable medical device is configured to provide an indication to a user corresponding to a battery status; and

wherein the third operating mode includes a magnetic resonance imaging (MRI) safe mode.

5. The apparatus of claim 1, wherein the Hall effect sensor is rotationally symmetric about an axis.

6. The apparatus of claim 1, wherein the Hall effect sensor comprises an integrated circuit.

7. The apparatus of claim 6, wherein the integrated circuit includes a heterostructure configured to increase a Hall mobility associated with the Hall effect sensor.

8. The apparatus of claim 6, wherein the processor and the Hall effect sensor are both included in a commonly shared integrated circuit package.

9. The apparatus of claim 8, wherein the processor and the Hall effect sensor are both included in a commonly shared integrated circuit.

10. The apparatus of claim 1, wherein the implantable medical device includes:

a polling circuit electrically coupled to the Hall effect sensor and configured to provide an excitation voltage to the Hall effect sensor; and

an analog-to-digital converter electrically coupled to the Hall effect sensor and configured to measure at least one of the current or the voltage provided by the Hall effect sensor in response to the magnetic field.

11. The apparatus of claim 10, wherein the processor is configured to control one or more excitation parameters associated with the polling circuit, the one or more parameters comprising at least one of:

(1) an excitation amplitude;

(2) an excitation pulse width;

(3) a timing between one or more excitation pulses;

or

(4) an excitation contact for delivery of the excitation voltage.

12. The apparatus of claim 10, wherein the Hall effect sensor and at least one of the polling circuit or the analog-to-digital converter are included in a commonly shared integrated circuit.

13. A method comprising:

sensing a magnetic field using a Hall effect sensor;

providing at least one of a current or a voltage in response to the sensed magnetic field; and

selecting an operating mode of an implantable medical device using at least one of the current or the voltage.

14. The method of claim 13, wherein the providing at least one of the current or the voltage includes using the Hall effect sensor;

wherein the method includes monitoring at least one of the current or the voltage; and

wherein the selecting the operating mode of the implantable medical device occurs at least in part in response to the monitoring at least one of the current or the voltage.

15. The method of claim 13, comprising:

sensing a magnitude of the magnetic field using the Hall effect sensor;

comparing the sensed magnitude of the magnetic field to at least one of a specified first threshold or a specified second threshold; and

selecting, in response to the comparing, the operating mode of the implantable medical device from a list including at least one of;

(1) a first operating mode when the magnitude of the magnetic field is below the specified first threshold;

(2) a second operating mode when the magnitude of the magnetic field exceeds or equals the specified first threshold over a specified first duration;

or

(3) a third operating mode when the magnitude of the magnetic field further exceeds or equals the specified second threshold over a specified second duration.

16. The method of claim 15, wherein the selecting the first operating mode includes selecting an ambulatory operating mode;

wherein the selecting the second operating mode includes selecting a battery status test mode and includes providing an indication to a user corresponding to a battery status; and

wherein the selecting the third operating mode includes selecting a magnetic resonance imaging (MRI) safe mode.

17. The method of claim 13, comprising:

exciting the Hall effect sensor using a polling circuit configured to provide an excitation voltage to the Hall effect sensor; and

wherein the monitoring at least one of the current or the voltage includes using an analog-to-digital converter electrically coupled to the Hall effect sensor.

18. The method of claim 17, comprising controlling one or more excitation parameters associated with the exciting the Hall effect sensor, the one or more excitation parameters including at least one of:

(1) an excitation amplitude;

(2) an excitation pulse width;

(3) a timing between one or more excitation pulses;

or

(4) an excitation contact for delivery of the excitation voltage.

19. The method claim 18, comprising:

sensing a magnitude of the magnetic field using the Hall effect sensor;

comparing the sensed magnitude to a specified magnitude window; and

increasing, in response to the comparing, the timing between one or more excitation pulses when the sensed magnitude is within the specified window throughout a specified duration.

20. The method of claim 18, comprising:

sensing a magnitude of the magnetic field using the Hall effect sensor;

comparing a sensed magnitude of the magnetic field to a specified magnitude window; and

limiting, in response to the comparing, the number of excitation pulses over a specified first duration when the sensed magnitude is within the specified window throughout a specified second duration.