SENSING TEMPERATURE WITHIN MEDICAL DEVICES

• US 20130278226A1
• Filed: 03/04/2013
• Published: 10/24/2013
• Est. Priority Date: 04/20/2012
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Cong, Peng, Gaddam, Venkat R., Olson, David P., Scott, Erik R., Smith, Todd V.
• Granted Patent: US 9,653,935 B2
• Time in Patent Office: Days
• US Class Current: 320/150
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: G01J 5/07 Arrangements for adjusting the solid angle of collected radiation, e.g. adjusting or orienting field of view, tracking position or encoding angular position optical collimating elements G01J5/0806
• CPC Class Codes: G01J 5/0887 Integrating cavities mimicking black bodies, wherein the heat propagation between the black body and the measuring element does not occur within a solid; Use of bodies placed inside the fluid stream for measurement of the temperature of gases; Use of the reemission from a surface, e.g. reflective surface; Emissivity enhancement by multiple reflections
• CPC Class Codes: G01K 11/006 using measurement of the effect of a material on microwaves or longer electromagnetic waves, e.g. measuring temperature via microwaves emitted by the object G01K17/003, G01J5/00 take precedence; measuring the effect of a material on X-, gamma- or particle radiation G01K11/30
• CPC Class Codes: G01K 11/20 using thermoluminescent materials G01K11/32 takes precedence
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 7/007192 in response to temperature

Abstract

Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue. In one example, a temperature sensor may sense a temperature of a portion of a device, wherein the portion is non-thermally coupled to the temperature sensor. A processor may then control charging of the rechargeable power source based on the sensed temperature.

Claims

1. A method comprising:

sensing a temperature of a portion of a medical device by a temperature sensor; and

controlling charging of a rechargeable power source based on the sensed temperature;

wherein the temperature sensor is configured to sense the temperature of the portion without being thermally-coupled to the portion

2. The method of claim 1, wherein sensing the temperature comprises sensing a level of infrared radiation emitted from the portion of the medical device, and sensing the temperature based on the sensed level.

3. The method of claim 1, wherein sensing the temperature comprises:

exciting a phosphor material disposed on the portion with electromagnetic radiation;

detecting a phase shift in a luminescence of the phosphor material in response to the excitation; and

determining the temperature of the portion based on the phase shift.

4. The method of claim 1, wherein the temperature sensor is mounted to a printed circuit board within a housing of the medical device and the housing comprises the portion.

5. The method of claim 1, wherein the temperature sensor is a first temperature sensor and the portion is a first portion, and wherein the method further comprises sensing, by a second temperature sensor, a temperature of a second portion of the device, and controlling charging of the rechargeable power source based on the sensed temperatures from the first and second temperature sensors.

6. The method of claim 5, wherein:

the first portion comprises a first housing surface of the medical device;

the second portion comprises a second housing surface of the medical device; and

the first housing surface opposes the second housing surface.

7. The method of claim 5, further comprising:

selecting to sense the temperature of the first portion with the first temperature sensor;

responsive to the selection, controlling a first shutter of the first temperature sensor to open; and

responsive to the selection, controlling a second shutter of the second temperature sensor to close.

8. The method of claim 1, further comprising:

comparing the sensed temperature to a threshold temperature; and

determining when the sensed temperature exceeds the threshold temperature, wherein controlling charging of the rechargeable power source comprises adjusting a power level used to charge the rechargeable power source.

9. The method of claim 1, further comprising:

calculating a temperature change rate from the sensed temperature when the rechargeable power source is charging;

determining when the temperature change rate increases subsequent to the temperature change rate decreasing during the charging; and

responsive to the determination, presenting a notification that instructs a user to replace a phase change material cartridge thermally coupled to the device.

10. The method of claim 1, further comprising:

calculating a temperature change rate from the sensed temperature when the rechargeable power source is charging;

determining a temperature change rate; and

calibrating a sensor based on the determined temperature change rate.

11. The method of claim 1, wherein the portion comprises a phase change material thermally coupled to at least one of a housing of the device and a coil that transfers energy to the rechargeable power source during charging.

12. The method of claim 1, wherein:

the medical device comprises an external charging device and the at least one processor; and

the rechargeable power source is housed by an implantable medical device.

13. The method of claim 1, wherein the medical device comprises an implantable medical device that houses the rechargeable power source.

14. The method of claim 1, further comprising:

comparing the sensed temperature to a fault condition threshold; and

disconnecting the rechargeable power source from at least one electrical circuit when the sensed temperature exceeds the fault condition threshold.

15. The method of claim 1, wherein the temperature sensor is not attached to the portion.

16. A system comprising:

a medical device comprising a housing;

a temperature sensor disposed within the housing and configured to sense a temperature of a portion of the medical device without being thermally coupled to the portion; and

at least one processor configured to control charging of a rechargeable power source based on the sensed temperature.

17. The system of claim 16, wherein the temperature sensor is configured to sense a level of infrared radiation emitted from the portion of the medical device, and sense the temperature based on the sensed level.

18. The system of claim 16, further comprising a phosphor material disposed on the portion, wherein:

the temperature sensor is configured to;

excite the phosphor material with electromagnetic radiation; and

detect a phase shift in a luminescence of the phosphor material in response to the excitation; and

the at least one processor is configured to determine the temperature of the portion based on the phase shift.

19. The system of claim 16, further comprising a printed circuit board within the housing of the device, wherein:

the temperature sensor is mounted to the printed circuit board; and

the housing comprises the portion.

20. The system of claim 16, wherein the temperature sensor is a first temperature sensor and the portion is a first portion, and wherein the system further comprises a second temperature sensor disposed within the housing and configured to sense a temperature of a second portion of the medical device, and the at least one processor is configured to control charging of the rechargeable power source based on the sensed temperatures from the first and second temperature sensors.

21. The system of claim 20, wherein:

the first portion comprises a first surface of the housing;

the second portion comprises a second surface of the housing; and

the first surface opposes the second surface.

22. The system of claim 20, wherein the at least one processor is configured to:

select the first temperature sensor to sense the temperature of the first portion instead of the second temperature sensor to sense the temperature of the second portion;

responsive to the selection, control a first shutter of the first temperature sensor to open; and

responsive to the selection, control a second shutter of the second temperature sensor to close.

23. The system of claim 16, wherein the at least one processor is configured to:

compare the sensed temperature to a threshold temperature;

determine when the sensed temperature exceeds the threshold temperature; and

adjust a power level used to charge the rechargeable power source.

24. The system of claim 16, wherein the at least one processor is configured to:

calculate a temperature change rate from the sensed temperature when the rechargeable power source is charging;

determine when the temperature change rate falls one of below or above a threshold during the charging; and

responsive to the determination, issue a notification that instructs a user to replace a phase change material cartridge thermally coupled to the medical device.

25. The system of claim 16, wherein the at least one processor is configured to:

calculate a temperature change rate from the sensed temperature when the rechargeable power source is charging; and

calibrate a sensor based on the temperature change rate.

26. The system of claim 16, wherein the portion comprises a phase change material thermally coupled to at least one of the housing of the medical device and a coil within the housing that transfers energy to the rechargeable power source during charging.

27. The system of claim 16, further comprising an implantable medical device comprising the rechargeable power source, wherein:

the medical device is an external charging device; and

the housing houses the at least one processor.

28. The system of claim 16, wherein the device comprises an implantable medical device that houses the rechargeable power source.

29. The system of claim 16, wherein the temperature sensor is remotely located as compared to the portion of the medical device from which the temperature is to be sensed.

30. The system of claim 16, wherein the temperature sensor is configured to sense the temperature via indirect measurement techniques.

31. A system comprising:

means for sensing a temperature of a portion of a medical device without being thermally coupled to the medical device; and

means for controlling charging of a rechargeable power source based on the sensed temperature.

32. A computer-readable storage medium comprising instructions that cause at least one processor to:

receive a temperature of a portion of a device, the temperature generated by a temperature sensor that is adapted to provide the temperature without being thermally-coupled to the portion; and

control charging of a rechargeable power source based on the temperature.