SYSTEMS AND METHODS FOR USE IN PULSE GENERATION

• US 20060259098A1
• Filed: 05/26/2006
• Published: 11/16/2006
• Est. Priority Date: 04/12/2004
• Status: Active Grant

• Current Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: ERICKSON, John H.
• Granted Patent: US 7,571,007 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

In one embodiment, an implantable medical device comprises: a rechargeable battery for powering the implantable medical device; an antenna for receiving RF power; and circuitry for charging the rechargeable battery using power received via the antenna, wherein the circuitry for charging comprises control circuitry that causes the circuitry for charging to recharge the rechargeable battery using multiple current levels applied in succession, and wherein the circuitry for charging switches from at least one of the current levels to another current level when a charging voltage of the rechargeable battery reaches a threshold value that is varied by the control circuitry over a lifespan of the rechargeable battery.

Claims

1. An implantable medical device, comprising:

a rechargeable battery for powering the implantable medical device;

an antenna for receiving RF power; and

circuitry for charging the rechargeable battery using power received via the antenna, wherein the circuitry for charging comprises control circuitry that causes the circuitry for charging to recharge the rechargeable battery using multiple current levels applied in succession, and wherein the circuitry for charging switches from at least one of the current levels to another current level when a charging voltage of the rechargeable battery reaches a threshold value that is varied by the control circuitry over a lifespan of the rechargeable battery.

2. The implantable medical device of claim 1 wherein the control circuitry causes the circuitry for charging to apply a maximum charging current when recharging operations are initiated and changes to a fractional amount of the maximum charging current when the voltage threshold is reached.

3. The implantable medical device of claim 2 wherein the control circuitry measures a voltage drop of the rechargeable battery that occurs when switching from the maximum charging current to the fractional amount.

4. The implantable medical device of claim 3 wherein the control circuitry adjusts the threshold value in response to measuring the voltage drop.

5. The implantable medical device of claim 1 wherein the control circuitry calculates the threshold value using a measured internal impedance of the rechargeable battery.

6. The implantable medical device of claim 1 wherein the circuitry for charging comprises circuitry for providing an alarm signal when a capacity of the rechargeable battery has fallen below a threshold amount.

7. The implantable medical device of claim 1 wherein the control circuitry switches between charging currents according to a table of threshold values, the table of threshold values storing values associated with beginning-of-life, middle-of-life, and end-of-life of the rechargeable battery.

8. The implantable medical device of claim 1 wherein the control circuitry accesses a value from memory that is indicative of a number of discharge cycles experienced by the rechargeable battery to control the threshold value.

9. The implantable medical device of claim 1 wherein the control circuitry increments the threshold value when a voltage of the rechargeable battery is less than or equal to second threshold value after completing charging according to one of the charging currents.

10. A method of recharging an implantable medical device after implantation within a patient, comprising:

transmitting a RF power signal;

receiving the RF power signal in an antenna in the implantable medical device;

rectifying a signal from the antenna;

recharging a rechargeable battery of the implantable medical device using the rectified signal, wherein the recharging applies multiple current levels to the rechargeable battery in succession, and wherein the circuitry for charging switches from at least one of the current levels to another current level when a charging voltage of the rechargeable battery reaches a threshold value that is variable over a lifespan of the rechargeable battery.

11. The method of claim 10 wherein the recharging applies a maximum charging current when recharging operations are initiated and changes to a fractional amount of the maximum charging current when the voltage threshold is reached.

12. The implantable medical device of claim 11 further comprising:

measuring a voltage drop of the rechargeable battery that occurs when switching from the maximum charging current to the fractional amount.

13. The method of claim 12 further comprising:

adjusting the threshold value in response to measuring the voltage drop.

14. The method of claim 10 further comprising:

calculating the threshold value using a measured internal impedance of the rechargeable battery.

15. The method of claim 10 further comprising:

providing an alarm signal when a capacity of the rechargeable battery has fallen below a threshold amount, wherein the capacity of the rechargeable battery is determined during recharging operations.

16. The method of claim 10 further wherein the recharging switches between charging currents according to a table of threshold values, the table of threshold values storing values associated with beginning-of-life, middle-of-life, and end-of-life of the rechargeable battery.

17. The method of claim 10 further comprising:

accessing a value memory that is indicative of a number of discharge cycles experienced by the rechargeable battery to control the threshold value.

18. The method of claim 10 further comprising:

adjusting the threshold value when a voltage of the rechargeable battery drops below a second threshold value after switching from a first charging current to second charging current.

19. An implantable medical device, comprising:

a rechargeable battery for powering the implantable medical device;

means for receiving RF power; and

means for charging the rechargeable battery using power received via the antenna, wherein means for charging comprises means for controlling the charging using multiple current levels applied in succession, and wherein the means for controlling switches from at least one of the current levels to another current level when a charging voltage of the rechargeable battery reaches a threshold value that is variable over a lifespan of the rechargeable battery.

20. The implantable medical device of claim 19 wherein the means for controlling adjusts the threshold value in response to a voltage drop of the rechargeable battery between a first charging current and a second charging current.