Implantable medical device powered by rechargeable battery

• US 7,813,801 B2
• Filed: 12/14/2006
• Issued: 10/12/2010
• Est. Priority Date: 12/15/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Youker, Nick A., Zhang, Cheng, Maile, Keith R., Root, Michael J., Huelskamp, Paul, Harguth, Robert S., Chavan, Abhi
• Primary Examiner(s): Manuel; Goerge
• Assistant Examiner(s): Wieland; Robert N
• Application Number:
  US11/610,894
• Publication Number:
  US 20070150019A1
• Time in Patent Office: 1,398 Days
• Field of Search: 606/169, 607/29, 600/515, 600/300, 128/848, 623/2.37, 429/91, 320/107, 320/136
• US Class Current: 607/29
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

A battery management circuit provides an implantable medical device with power management that allows safe and efficient use of a rechargeable battery. Various ways of monitoring the energy level of the rechargeable battery and controlling the battery recharging process for user convenience and safety are provided.

Claims

1. A system, comprising:

an implantable medical device including a power source including;

a rechargeable battery;

a battery status monitor coupled to the rechargeable battery, the battery status monitor including a terminal voltage detector adapted to detect a terminal voltage of the rechargeable battery;

a recharging controller coupled to the battery status monitor, the recharging controller adapted to control a process of recharging the rechargeable battery using the terminal voltage and including a phase controller, the process including a fast-charge phase and a trickle-charge phase, the phase controller adapted to initiate the fast-charge phase in response to a recharging command, to switch from the fast-charge phase to the trickle-charge phase when the terminal voltage reaches a predetermined phase-switch threshold voltage, and to terminate the trickle-charge phase when the terminal voltage reaches a predetermined end-of-charge threshold voltage; and

a recharging circuit coupled to the recharging controller and the rechargeable battery, the recharging circuit including;

a power receiver adapted to receive a power-transmission signal; and

a power converter adapted to convert the power-transmission signal to a constant-current signal during the fast-charge phase and to a constant-voltage signal during the trickle-charge phase.

2. The system of claim 1, further comprising an external system communicatively coupled to the implantable medical device, and wherein the phase controller is adapted to initiate the fast-charge phase in response to a user command transmitted from the external system.

3. The system of claim 1, further comprising an external system communicatively coupled to the implantable medical device, the external system including a power transmitter to transmit the power-transmission signal to the implantable medical device, and wherein the phase controller is adapted to initiate the fast-charge phase in response to receipt of the power-transmission signal.

4. A method for operating an implantable medical device, the method comprising:

detecting a terminal voltage of a rechargeable battery of the implantable medical device;

controlling a process of recharging the rechargeable battery using the terminal voltage, the process including a fast-charge phase and a trickle-charge phase;

receiving a recharging command;

initiating the fast-charge phase in response to the recharging command;

charging the rechargeable battery using a constant current during the fast-charge phase;

switching from the fast-charge phase to the trickle-charge phase when the terminal voltage exceeds a predetermined phase-switch threshold voltage;

charging the rechargeable battery using a constant voltage during the trickle-charge phase; and

terminating the trickle-charge phase when the terminal voltage reaches a predetermined end-of-charge threshold voltage.

5. The method of claim 4, wherein receiving the recharge command comprises receiving a command initiating the process of recharging the rechargeable battery from a user.

6. The method of claim 4, wherein receiving the recharge command comprises receiving a signal indicating that the implantable medical device has received a power-transmission signal that carries energy for recharging the rechargeable battery.

7. A system, comprising:

an implantable medical device including a power source including;

a rechargeable battery;

a recharging circuit coupled to the rechargeable battery, the recharging circuit adapted to recharge the rechargeable battery; and

a recharging controller coupled to the recharging circuit, the recharging controller adapted to suspend the recharging of the rechargeable battery during a primary period and to control the recharging of the rechargeable battery during a secondary period, the recharging controller including;

a primary period timer adapted to initiate the primary period in response to an initiation signal; and

a secondary period timer adapted to initiate the secondary period when the primary period expires.

8. The system of claim 7, wherein the primary period timer is adapted to time a predetermined duration as the primary period.

9. The system of claim 7, wherein the power source comprises a battery status monitor coupled to the rechargeable battery, the battery status monitor adapted to detect an energy level of the rechargeable battery, and wherein the recharging controller is adapted to control the recharging of the rechargeable battery using the energy level.

10. The system of claim 9, wherein the primary period timer is adapted to stop the primary period when the energy level drops below a discharge threshold.

11. The system of claim 9, wherein the primary period timer is adapted to stop the primary period when a predetermined duration expires or when the energy level drops below a discharge threshold, whichever occurs first.

12. The system of claim 9, wherein the recharging controller is adapted to control the recharging of the rechargeable battery during the secondary period using the energy level.

13. The system of claim 12, wherein the recharging controller is adapted to initiate a recharging process during the secondary period when the energy level drops below a discharge threshold and to terminate that recharging process when the energy level rises to a recharge threshold.

14. The system of claim 9, wherein the battery status monitor comprises means for detecting a parameter indicative of a state of charge of the rechargeable battery.

15. The system of claim 7, wherein the recharging controller is adapted to control the recharging of the rechargeable battery during the secondary period based on a specified longevity of the implantable medical device.

16. The system of claim 15, wherein the recharging controller is adapted to initiate a recharging process periodically during the secondary period.

17. A method for operating an implantable medical device, the method comprising:

initiating a primary period in response to an initiation signal indicating that the implantable medical device is initiated for use;

initiating a secondary period in response to a termination of the primary period, the secondary period extending longevity of the implantable medical device after the termination of the primary period;

suspending recharging of a rechargeable battery of the implantable medical device during the primary period;

detecting an energy level of the rechargeable battery; and

controlling the recharging of the rechargeable battery using the energy level during the secondary period.

18. The method of claim 17, comprising:

timing a predetermined duration; and

terminating the primary period when the predetermined duration expires.

19. The method of claim 17, comprising terminating the primary period when the energy level drops below a discharge threshold.

20. The method of claim 17, wherein control the recharging of the rechargeable battery during the secondary period comprises:

initiating a recharging process during the secondary period when the energy level drops below a discharge threshold; and

terminating that recharge process when the energy level rises to a recharge threshold.

21. The method of claim 17, wherein controlling the recharging of the rechargeable battery during the secondary period comprises controlling the recharging of the rechargeable battery based on a specified longevity of the implantable medical device.

22. The method of claim 21, wherein controlling the recharging of the rechargeable battery during the secondary period comprises initiating a recharging process periodically during the secondary period.

23. A system, comprising:

an implantable medical device including;

a feature circuit including one or more of a sensing circuit to sense one or more physiological signals and an electrical stimulation circuit to deliver electrical stimulation; and

a power source adapted to provide power to the feature circuit, the power source including;

a rechargeable battery;

a non-rechargeable battery;

a battery status monitor coupled to the rechargeable battery and the non-rechargeable battery, the battery status monitor adapted to detect at least one of a first energy level of the rechargeable battery and a second energy level of the non-rechargeable battery; and

a battery switch coupled between the feature circuit and the power source, the battery switch adapted to selectively provide an electrical connection between the feature circuit and one of the rechargeable battery and the non-rechargeable battery using at least one of the first energy level and the second energy level.

24. The system of claim 23, wherein the battery switch is programmed to provide the electrical connection between the feature circuit and the non-rechargeable battery while the second energy level is above a predetermined threshold and to provide the electrical connection between the feature circuit and the rechargeable battery while the second energy level is not above a predetermined threshold.

25. The system of claim 23, wherein the battery switch is programmed to provide the electrical connection between the feature circuit and the rechargeable battery while first energy level is above a predetermined threshold and to provide the electrical connection between the feature circuit and the non-rechargeable battery while the first energy level is not above a predetermined threshold.

26. The system of claim 23, wherein the battery status monitor comprises means for detecting a parameter indicative of a state of charge of each of the rechargeable battery and the non-rechargeable battery.

27. The system of claim 26, wherein the battery status monitor comprises a warning signal generator adapted to produce one or more warning signals using the parameter indicative of the state of charge.

28. A method for operating an implantable medical device including a rechargeable battery and a non-rechargeable battery, the method comprising:

detecting at least one of a first energy level of the rechargeable battery and a second energy level of the non-rechargeable battery; and

selecting one of the rechargeable battery and the non-rechargeable battery to power the implantable medical device using at least one of the first energy level and the second energy level.

29. The method of claim 28, comprising:

powering the implantable medical device using the non-rechargeable battery while the second energy level is above a predetermined threshold; and

powering the implantable medical device using the rechargeable battery while the second energy level is not above the predetermined threshold.

30. The method of claim 28, comprising:

powering the implantable medical device using the rechargeable battery while the first energy level is above a predetermined threshold; and

powering the implantable medical device using the non-rechargeable battery while the first energy level is not above the predetermined threshold.

31. The method of claim 28, wherein detecting at least one of the first energy level and the second energy level comprises detecting a parameter indicative of a state of charge of at least one of the rechargeable battery and the non-rechargeable battery.

32. The method of claim 31, further comprising producing one or more warning signals using the parameter indicative of the state of charge.

33. A system, comprising:

an implantable sensor module including;

a pressure sensor to sense a signal indicative of a blood pressure; and

a power source adapted to provide power to the pressure sensor, the power source including;

a rechargeable battery;

a battery status monitor coupled to the rechargeable battery, the battery status monitor adapted to detect an energy level of the rechargeable battery;

a recharging controller coupled to the battery status monitor, the recharging controller adapted to control a process of recharging the rechargeable battery using the energy level; and

a recharging circuit coupled to the recharging controller and the rechargeable battery, the recharging circuit including;

an ultrasonic power receiver to receive an ultrasonic signal carrying an ultrasonic energy and having a frequency in a range between 38 kHz and 42 kHz; and

a piezoelectric transducer to convert the ultrasonic energy to an electrical energy for recharging the rechargeable battery.

34. The system of claim 33, wherein the implantable sensor module comprises an implant telemetry circuit adapted to transmit data representative of the sensed signal to another implantable device.

35. The system of claim 34, further comprising an external system communicatively coupled to the implantable sensor module, and wherein the implant telemetry circuit is further adapted to transmit the data representative of the sensed signal to the external system.

36. The system of claim 33, further comprising:

an external system to transmit the ultrasonic signal; and

an integrated ultrasonic data transmission and power transmission link coupling between the external system and the implantable sensor module,

and wherein the ultrasonic power receiver is adapted to receive the ultrasonic signal via the integrated ultrasonic data transmission and power transmission link, the ultrasonic signal modulated for data transmission.

37. The system of claim 33, wherein the battery status monitor comprises means for detecting a parameter indicative of a state of charge of the rechargeable battery.

38. The system of claim 37, wherein the battery status monitor comprises a warning signal generator adapted to produce one or more warning signals using the parameter indicative of the state of charge.

39. A method for operating a medical device system, the method comprising:

sensing a signal indicative of a blood pressure using a first implantable medical device;

powering a circuit of the first implantable medical device using a rechargeable battery;

detecting an energy level of the rechargeable battery;

receiving an ultrasonic signal carrying an ultrasonic energy from an external system, the ultrasound signal having a frequency in a range between 38 kHz and 42 kHz;

converting the ultrasonic energy to an electrical energy;

recharging the rechargeable battery using the electrical energy; and

controlling the recharging the rechargeable battery using the energy level.

40. The method of claim 39, further comprising transmitting data representative of the sensed signal to a second implantable medical device.

41. The method of claim 40, further comprising transmitting the data representative of the sensed signal to an external system.

42. The method of claim 39, further comprising transmitting data from the external system to the first implantable medical device by modulating the ultrasonic signal.

43. The method of claim 39, wherein detecting the energy level comprises detecting a parameter indicative of a state of charge of the rechargeable battery.

44. The method of claim 43, further comprising producing one or more warning signals using the parameter indicative of the state of charge.