Techniques for Controlling Charging of Batteries in an External Charger and an Implantable Medical Device

• US 20120239118A1
• Filed: 05/29/2012
• Published: 09/20/2012
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Ozawa, Robert Dai, Carbunaru, Rafael
• Granted Patent: US 8,644,933 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61F 2250/0001 Means for transferring electromagnetic energy to implants
• 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 50/10 using inductive coupling
• 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 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

Disclosed are charging algorithms implementable in an external charger for controlling the charging of both an external battery in the external charger and an implant battery in an implantable medical device. Because full-powered simultaneous charging of both batteries can generate excessive heat in the external charger, the various charging algorithms are designed to ensure that both batteries are ultimately charged, but in a manner considerate of heat generation. In some embodiments, the charging algorithms prevent simultaneous charging of both batteries by arbitrating which battery is given charging precedence at a given point in time. In other embodiments, the charging algorithms allow for simultaneous charging of both batteries, but with at least one of the batteries being only weakly charged at low power levels. In other embodiments, the temperature generated in the external charger is monitored and used to control the charging algorithm.

Claims

1. An external charger for interfacing with an implantable medical device, comprising:

a battery charging circuit for controlling the charging of an external battery in the external charger;

a transmitter for controlling a wireless transmission to the implantable medical device, wherein the wireless transmission provides power to charge an implant battery in the implantable medical device;

control circuitry for implementing an algorithm to controllably enable the battery charging circuit and the transmitter in the event that the control circuitry determines that both the external battery and the implant battery require charging.

2. The external charger of claim 1, wherein the algorithm first enables one of the battery charging circuit or the transmitter to respectively fully charge the external battery or the implant battery, and then enables the other of the battery charging circuit or the transmitter to fully charge the other of the external battery or the implant battery.

3. The external charger of claim 1, wherein the algorithm alternates between enabling the battery charging circuit and the transmitter to respectively alternate between the charging of the external battery and the implant battery.

4. The external charger of claim 1, wherein the algorithm enables both the battery charging circuit and the transmitter simultaneously, but reduces an amount of power to either or both of the battery charging circuit and the transmitter.

5. The external charger of claim 4, wherein the algorithm reduces the amount of power to the battery charging circuit by reducing a battery charging current from the battery charging circuit to the external battery.

6. The external charger of claim 4, wherein the algorithm reduces the amount of power to the battery charging circuit by duty cycling a battery charging current from the battery charging circuit to the external battery.

7. The external charger of claim 4, wherein the algorithm reduces the amount of power to the transmitter by reducing a power supply voltage for the transmitter.

8. The external charger of claim 4, wherein the algorithm reduces the amount of power to the transmitter by duty cycling a power supply voltage for the transmitter.

9. The external charger of claim 1, further comprising a temperature sensor for indicating a temperature to the control circuitry.

10. The external charger of claim 9, wherein the control circuitry implements a different algorithm to controllably enable the battery charging circuit and the transmitter in the event that the control circuitry determines that a pre-determined temperature has been exceeded.

11. The external charger of claim 1, further comprising a switch for passing either a voltage of the external battery or a DC voltage as generated from an AC power source as a power supply for the transmitter.

12. An external charger for interfacing with an implantable medical device, comprising:

an external battery in the external charger for producing a battery voltage;

a DC voltage produced from an AC power source, wherein the DC voltage is usable to charge the external battery; and

a transmitter for providing power wirelessly to charge an implant battery in an implantable medical device, the transmitter comprising a resonant circuit powered by a power supply voltage, wherein the power supply voltage is selectable between the battery voltage and the DC voltage.

13. The external charger of claim 12, wherein the power supply voltage is selected as the DC voltage if the battery voltage is below a pre-determined level, but is selected as the battery voltage if the battery voltage is above a pre-determined level.

14. The external charger of claim 12, further comprising a port for receiving the DC voltage.

15. The external charger of claim 12, further comprising a DC-DC regulator, and wherein the DC voltage is generated by the first regulator.

16. The external charger of claim 12, further comprising a switch for selecting the power supply voltage between the battery voltage and the DC voltage.

17. The external charger of claim 12, further comprising a battery charging circuit for controlling the charging of the external battery in the external charger.

18. The external charger of claim 17, wherein the DC voltage is provided to the battery charging circuit to charge the external battery.

19. The external charger of claim 17, further comprising control circuitry for implementing an algorithm to controllably enable the battery charging circuit and the transmitter in the event that the control circuitry determines that both the batteries in the external charger and the implant require charging.

20. An external charger for interfacing with an implantable medical device, comprising:

an external battery in the external charger for producing a battery voltage;

a battery charging circuit for controlling the charging of the external battery;

a DC voltage, wherein the DC voltage is provided to the battery charging circuit to allow the external battery to be charged;

a coil to provide power wirelessly to charge an implant battery in an implantable medical device;

a transmitter for driving the coil;

control circuitry programmed to control the battery charging circuit and the transmitter in the event that the control circuitry determines that both the external battery and the implant battery requires charging.

21. The external charger of claim 20, wherein the transmitter receives an oscillating drive signal.

22. The external charger of claim 20, wherein the transmitter is powered by a power supply voltage, and further comprising switching circuitry to pass either (i) the battery voltage or (ii) either the DC voltage or a regulated version of the DC voltage to the power supply voltage.

23. The external charger of claim 22, wherein (i) is passed if the battery voltage is above a pre-determined level, and wherein (ii) is passed if the battery voltage is below a pre-determined level.

24. The external charger of claim 20, wherein the control circuitry first enables one of the battery charging circuit or the transmitter to respectively fully charge the external battery or the implant battery, and then fully charges the other of the external battery of the implant battery.

25. The external charger of claim 20, wherein the control circuitry alternates between enabling the battery charging circuit and the transmitter to respectively alternate between the charging of the external battery and the implant battery.

26. The external charger of claim 20, wherein the control circuitry enables both the battery charging circuit and the transmitter simultaneously, but reduces an amount of power to either or both of the battery charging circuit and the transmitter in the event that the control circuitry determines that both the external battery and the implant battery requires charging.

27. The external charger of claim 20, further comprising a temperature sensor for indicating a temperature to the control circuitry.

28. The external charger of claim 27, wherein the control circuitry implements a different algorithm to control the battery charging circuit and the transmitter in the event that the control circuitry determines that a pre-determined temperature has been exceeded.