Battery management for an implantable medical device

• US 9,855,438 B2
• Filed: 06/14/2016
• Issued: 01/02/2018
• Est. Priority Date: 07/20/2011
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Parramon, Jordi, Marnfeldt, Goran N., Ozawa, Robert, Feldman, Emanuel, Peterson, Dave, He, Yuping
• Primary Examiner(s): Porter, Jr., Allen
• Application Number:
  US15/182,367
• Publication Number:
  US 20160287886A1
• Time in Patent Office: 567 Days
• Field of Search: 607 61
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

Battery management circuitry for an implantable medical device such as an implantable neurostimulator is described. The circuitry has a T-shape with respect to the battery terminal, with charging circuitry coupled between rectifier circuitry and the battery terminal on one side of the T, and load isolation circuitry coupled between the load and the battery terminal on the other side. The load isolation circuitry can comprise two switches wired in parallel. An undervoltage fault condition opens both switches to isolate the battery terminal from the load to prevent further dissipation of the battery. Other fault conditions will open only one the switches leaving the other closed to allow for reduced power to the load to continue implant operations albeit at safer low-power levels. The battery management circuitry can be fixed in a particular location on an integrated circuit which also includes for example the stimulation circuitry for the electrodes.

Claims

1. Circuitry for an implantable medical device, comprising:

charging circuitry for providing power to a battery terminal node;

isolation circuitry comprising first and second load switches in parallel, wherein both of the first and second load switches are directly connected to the battery terminal node and to a load voltage; and

active circuitry within the implantable medical device, wherein the load voltage comprises a power supply voltage for the active circuitry,

wherein the first load switch is opened if a voltage at the battery terminal node falls below a threshold, and

wherein the second load switch is opened if at least one other fault condition is asserted.

2. The circuitry of claim 1, wherein the first load switch has a first resistance, and the second load switch has a second resistance smaller than the first resistance.

3. The circuitry of claim 1,

wherein the second load switch is also opened if the voltage at the battery terminal node falls below the threshold.

4. The circuitry of claim 3, wherein the first load switch has a first resistance, and the second load switch has a second resistance smaller than the first resistance.

5. The circuitry of claim 1, wherein the at least one other fault condition comprises an overcurrent between the battery terminal node and the load.

6. The circuitry of claim 1, wherein the at least one other fault conditions comprise an overcurrent between the battery terminal node and the load and an emergency shutdown condition.

7. The circuitry of claim 6, wherein the emergency shutdown condition comprises a magnetic field generated external to the implantable medical device.

8. The circuitry of claim 1, wherein the active circuitry comprises stimulation circuitry configured to provide stimulation to a plurality of electrodes of the implantable medical device.

9. The circuitry of claim 1, wherein the active circuitry comprises one or more voltage regulators for producing power supply voltages for other circuitry in the implantable medical device.

10. Circuitry for an implantable medical device, comprising:

charging circuitry for providing power to a battery terminal node;

isolation circuitry comprising a plurality of load switches coupled in parallel between the battery terminal node and a load voltage;

isolation circuitry comprising a plurality of load switches in parallel, wherein the plurality of load switches are directly connected to the battery terminal node and to a load voltage;

active circuitry within the implantable medical device, wherein the load voltage comprises a power supply voltage for the active circuitry;

an undervoltage detector, wherein the undervoltage detector is configured to assert an undervoltage signal if a voltage at the battery terminal node falls below a first threshold;

an overcurrent detector, wherein the overcurrent detector is configured to assert an overcurrent signal if a current between the battery terminal node and the load exceeds a second threshold; and

a magnetic field detector, wherein the magnetic field detector is configured to assert a magnetic field signal upon detection of a magnetic field external to the implantable medical device,

wherein the plurality of load switches are controlled by the undervoltage signal, the overcurrent signal, and the magnetic field signal.

11. The circuitry of claim 10, wherein the plurality of load switch switches each have different resistances.

12. The circuitry of claim 11, further comprising an OR gate, wherein the OR gate is configured to receive the undervoltage signal, the overcurrent signal, and the magnetic field signal, and wherein the OR gate is configured to output a reset signal to the second load switch, such that if any of the undervoltage signal, the overcurrent signal, or the magnetic field signal are asserted, the reset signal opens the second load switch.

13. The circuitry of claim 12, wherein only the undervoltage signal controls the first load switch, such that the first load switch is opened if the undervoltage signal is asserted.

14. The circuitry of claim 13, wherein the first load switch has a first resistance, and the second load switch has a second resistance smaller than the first resistance.

15. The circuitry of claim 10, wherein the plurality of load switches comprises a first load switch and a second load switch.

16. The circuitry of claim 10, wherein the active circuitry comprises stimulation circuitry configured to provide stimulation to a plurality of electrodes of the implantable medical device.

17. The circuitry of claim 10, wherein the active circuitry comprises one or more voltage regulators for producing power supply voltages for other circuitry in the implantable medical device.

18. Circuitry for an implantable medical device, comprising:

charging circuitry for providing power to a battery terminal node;

isolation circuitry comprising first and second load switches coupled in parallel between the battery terminal node and a load voltage, wherein the first and second load switches have first terminals that are directly connected, and wherein the first and second switches have second terminals that are directly connected; and

active circuitry within the implantable medical device, wherein the load voltage comprises a power supply voltage for the active circuitry,

wherein the first load switch is opened if a voltage at the battery terminal node falls below a threshold, and

wherein the second load switch is opened if at least one other fault condition is asserted.

19. The circuitry of claim 18, wherein the first terminals are further directly connected to the battery terminal node, and wherein the second terminals are further directly connected to the load voltage.

20. The circuitry of claim 18, wherein the first load switch has a first resistance, and the second load switch has a second resistance smaller than the first resistance.