Adaptive rate recharging system

Patent metadata

Field	Value
Publication number	US-9270134-B2
Application number	US-201313749481-A
Country	US
Kind code	B2
Filing date	Jan 24, 2013
Priority date	Jan 27, 2012
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

Devices, systems, and techniques for selecting a period for charging an implantable rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. A system may control a charging module to begin charging the rechargeable power source of the implantable medical device with a high power level. The system may then determine an estimated heat loss based on power initially delivered to the rechargeable power source when beginning the charging. Based on this estimated heat loss during the initial period of recharging, the system may select a boost period that includes a duration of time that the rechargeable power source is charged with the high power level.

First claim

What is claimed is:

1. A method comprising:
controlling a charging module to begin charging a rechargeable power source of an implantable medical device with a high power level, wherein the high power level is higher than a non-zero low power level;
determining, by a processor, an estimated heat loss based on power initially delivered to the rechargeable power source when beginning the charging with the high power level;
selecting, by the processor, a boost period based on the estimated heat loss; and
continuing to control the charging module to charge the rechargeable power source with the high power level for a duration of the boost period.

2. The method of claim 1 , further comprising:
comparing a high power charging time to the boost period, wherein the high power charging time is an elapsed time with which the rechargeable power source was charged with the high power level; and
terminating charging with the high power level when the high power charging time exceeds the duration of the boost period.

3. The method of claim 2 , further comprising:
selecting the low power level when the high power charging time exceeds the boost period; and
charging the rechargeable power source with the low power level until the rechargeable power source is fully charged, wherein the low power level comprises a lower power level than the high power level.

4. The method of claim 1 , wherein determining the estimated heat loss comprises:
calculating a power delivered to a primary coil of an external charging device;
calculating a power lost in the primary coil; and
subtracting the power lost in the primary coil and the power delivered to the rechargeable power source from the power delivered to the primary coil.

5. The method of claim 1 , further comprising calculating the power delivered to the rechargeable power source by measuring an electrical current flowing to the rechargeable power source, measuring a voltage of the rechargeable power source, and multiplying the electrical current by the voltage.

6. The method of claim 1 , wherein:
selecting the boost period comprises selecting one of a plurality of boost periods that corresponds to the estimated heat loss; and
the plurality of boost periods comprise different durations of time.

7. The method of claim 1 , wherein the duration of the boost period is between approximately 5 minutes and 35 minutes.

8. The method of claim 1 , further comprising:
generating a first electrical current in a primary coil of a charging device based on the high power level; and
inducing an electrical current in an implanted secondary coil to charge the rechargeable power source.

9. The method of claim 1 , further comprising:
calculating, by the processor, an estimated cumulative thermal dose delivered to the patient during charging of the rechargeable power source over at least the duration of the boost period; and
selecting, by the processor, a subsequent power level for charging the rechargeable power source after the boost period based on the estimated cumulative thermal dose.

10. The method of claim 1 , wherein the processor is housed by one of the implantable medical device or an external charging device.

11. The method of claim 1 , wherein the high power level is a first power level, and wherein the method further comprises:
controlling the charging module to begin charging the rechargeable power source of an implantable medical device with a second power level different than the first power level;
determining, by the processor, an estimated heat loss for the second power level based on power delivered to the rechargeable power source when charging with the second power level;
selecting, by the processor, a boost period based on the estimated heat loss for the second power level;
calculating a first charge addition to the rechargeable power source for the first power level during the boost period of the first power level;
calculating a second charge addition to the rechargeable power source for the second power level during the boost period of the second power level;
determining a highest charge addition by comparing the first forecast charge addition to the second forecast charge addition; and
selecting, by the processor, the first power level for charging the rechargeable power source when the first power level is associated with the highest charge addition.

12. The method of claim 1 , wherein the rechargeable power source comprises a negative electrode comprising lithium titanate.

13. The method of claim 1 , wherein continuing to control the charging module to charge the rechargeable power source with the high power level comprises controlling the charging module to charge the rechargeable power source at a charge rate greater than approximately 0.5 C.

14. The method of claim 1 , wherein continuing to control the charging module to charge the rechargeable power source with the high power level comprises controlling the charging module to charge the rechargeable power source at a charge rate greater than approximately 5.0 C.

15. The method of claim 1 , wherein continuing to control the charging module to charge the rechargeable power source with the high power level comprises controlling the charging module to charge the rechargeable power source at a constant voltage greater than a full charge voltage of the rechargeable power source.

16. A system comprising:
a processor configured to:
control a charging module to begin charging a rechargeable power source of an implantable medical device with a high power level, wherein the high power level is higher than a non-zero low power level;
determine an estimated heat loss based on power initially delivered to the rechargeable power source when beginning to charge the rechargeable power source with the high power level;
select a boost period based on the estimated heat loss; and
continue to control the charging module to charge the rechargeable power source with the high power level for a duration of the boost period.

17. The system of claim 16 , wherein the processor is configured to:
compare a high power charging time to the boost period, wherein the high power charging time is an elapsed time with which the rechargeable power source was charged with the high power level; and
terminate charging with the high power level when the high power charging time exceeds the duration of the boost period.

18. The system of claim 17 , further comprising a charging module, wherein:
the processor is configured to select the low power level when the high power charging time exceeds the boost period;
the charging module is configured to charge the rechargeable power source with the low power level until the rechargeable power source is fully charged; and
the low power level comprises a lower power level than the high power level.

19. The system of claim 16 , wherein the processor is configured to:
calculate a power delivered to a primary coil of an external charging device;
calculate a power lost in the primary coil; and
subtract the power lost in the primary coil and the power delivered to the rechargeable power source from the power delivered to the primary coil to determine the estimated heat loss.

20. The system of claim 19 , wherein the processor is configured to multiply a measured electrical current flowing to the rechargeable power source by a measured voltage of the rechargeable power source to calculate the power delivered to the rechargeable power source.

21. The system of cl

Assignees

• Medtronic Inc

Inventors

• Gaddam Venkat R
• Bornhoft Reid K
• Kelly Kevin J
• Olson David P
• Smith Todd V

Classifications

• H02J50/10

  using inductive coupling · CPC title

• H02J7/927

  with introduction of pulses during the charging process · CPC title

• H02J7/90

  Regulation of charging or discharging current or voltage · CPC title

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H02J2105/46

  Medical devices, medical implants or life supporting devices · CPC title