System and method for determining remaining battery life for an implantable medical device
First Claim
1. In an implantable medical device (IMD) that is powered by a battery exhibiting a characteristic voltage drop at any given current drain from a beginning-of-life battery voltage to an elective replacement indicator battery voltage, the IMD imposing a quiescent current drain on the battery and periodically imposes an episodic current drain on the battery in an energy consuming incident including one or more of delivery of a therapy through a therapy delivery channel or monitoring a physiologic condition through a monitoring channel, the quiescent and episodic current drain consuming battery energy that cumulatively causes battery voltage to drop, a method of estimating the remaining life of the battery until battery voltage drops to the elective replacement indicator battery voltage comprising the steps of:
- periodically measuring battery voltage and averaging a plurality of battery voltage measurements to derive an average measured battery voltage;
estimating the estimated past current drain of the IMD comprising an average of the sum of the quiescent current drain and the episodic current drain; and
determining the estimated remaining longevity from the measured voltage and the estimated past current drain.
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Abstract
A system and method for determining a remaining life estimate of the remaining battery life of a battery of an implantable medical device (IMD). The IMD battery preferably exhibits a highly reproducible monotonically decreasing discharge curve. The estimated remaining life estimates are derived by periodically measuring battery voltage, and estimating the estimated past current drain of the IMD comprising an average of the sum of the quiescent current drain and therapy delivery current drain, and determining the estimated remaining longevity from the measured voltage and the estimated past current drain.
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Citations
31 Claims
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1. In an implantable medical device (IMD) that is powered by a battery exhibiting a characteristic voltage drop at any given current drain from a beginning-of-life battery voltage to an elective replacement indicator battery voltage, the IMD imposing a quiescent current drain on the battery and periodically imposes an episodic current drain on the battery in an energy consuming incident including one or more of delivery of a therapy through a therapy delivery channel or monitoring a physiologic condition through a monitoring channel, the quiescent and episodic current drain consuming battery energy that cumulatively causes battery voltage to drop, a method of estimating the remaining life of the battery until battery voltage drops to the elective replacement indicator battery voltage comprising the steps of:
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periodically measuring battery voltage and averaging a plurality of battery voltage measurements to derive an average measured battery voltage;
estimating the estimated past current drain of the IMD comprising an average of the sum of the quiescent current drain and the episodic current drain; and
determining the estimated remaining longevity from the measured voltage and the estimated past current drain. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
the estimating step further comprises estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining step further comprises scaling the average remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled average remaining life estimate until the battery elective replacement interval voltage is reached.
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3. The method of claim 1, wherein the estimating step further comprises estimating, from the estimated past current drain and the average measured battery voltage, a maximum percentile remaining life estimate of the time remaining during which a predetermined maximum percentage of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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4. The method of claim 3, further comprising:
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adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
the estimating step further comprises estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining step further comprises scaling the maximum percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled maximum percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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5. The method of claim 1, wherein the estimating step further comprises estimating, from the estimated past current drain and the average measured battery voltage, a 95th percentile remaining life estimate of the time remaining during which 95% of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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6. The method of claim 5, further comprising the step of:
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adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating step further comprises estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bobs; and
the determining step further comprises scaling the 95th percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain arid the estimated future current drain to derive a scaled 95th percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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7. The method of claim 1, wherein the estimating step further comprises:
determining, from the estimated past current drain and the average measured battery voltage, a minimum percentile remaining life estimate of the time remaining during which a predetermined minimum percentage of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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8. The method of claim 5, further comprising the step of:
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adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating step further comprises estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining step further comprises scaling the minimum percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled minimum percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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9. The method of claim 1, wherein the estimating step further comprises:
determining, from the estimated past current drain and the average measured battery voltage, a 5th percentile remaining life estimate of the time remaining during which 5% of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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10. The method of claim 9, further comprising the step of:
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adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating step further comprises estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining step further comprises scaling the 5th percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled 5th percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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11. The method of claim 1, wherein:
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the IMD comprises a cardiac pacing system that delivers pacing pulses in energy consuming incidents through a pacing lead and electrode and body tissue comprising a load having an impedance, whereby delivery of each pacing pulse consumes a predetermined bolus of energy, and the estimating step further comprises measuring the impedance of the load.
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12. The method of claim 1, wherein:
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the IMD comprises an electrical stimulator that delivers stimulation pulses in energy consuming incidents through an electrode and body tissue comprising a load having an impedance, whereby delivery of each stimulation pulse consumes a predetermined bolus of energy, and the estimating step further comprises measuring the impedance of the load.
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13. An implantable medical device (IMD) that is powered by a battery exhibiting a characteristic voltage drop at any given current drain from a beginning-of-life battery voltage to an elective replacement indicator battery voltage, the IMD imposing a quiescent current drain on the battery and periodically imposes an episodic current drain on the battery in an energy consuming incident including one or more of delivery of a therapy through a therapy delivery channel or monitoring a physiologic condition through a monitoring channel, the quiescent and episodic current drain consuming battery energy that cumulatively causes battery voltage to drop, a method of estimating the remaining life of the battery until battery voltage drops to the elective replacement indicator battery voltage, the IMD further comprising:
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means for periodically measuring battery voltage and averaging a plurality of battery voltage measurements to derive an average measured battery voltage;
estimating means for estimating the estimated past current drain of the IMD comprising an average of the sum of the quiescent current drain and episodic current drain; and
determining means for determining the estimated remaining longevity from the measured voltage and the estimated past current drain. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
adjusting means for adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating means further comprises means for estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining means further comprises means for scaling the average remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled average remaining life estimate until the battery elective replacement interval voltage is reached.
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15. The IMD of claim 13, wherein the estimating means further comprises means for determining, from the estimated past current drain and the average measured battery voltage, a maximum percentile remaining life estimate of the time remaining during which a maximum percentage of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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16. The IMD of claim 15, and further comprising:
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adjusting means for adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating means further comprises means for estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining means further comprises means for scaling the maximum percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled maximum percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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17. The IMD of claim 13, wherein the estimating means further comprises means for determining, from the estimated past current drain and the average measured battery voltage, a 95th percentile remaining life estimate of the time remaining during which 95% of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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18. The IMD of claim 17, and further comprising:
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adjusting means for adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating means further comprises means for estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining means further comprises means for scaling the 95th percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled 95th percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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19. The IMD of claim 13, wherein the estimating means further comprises means for determining, from the estimated past current drain and the average measured battery voltage, a minimum percentile remaining life estimate of the time remaining during which a minimum percentage of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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20. The IMD of claim 19, and further comprising:
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means for adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating means further comprises means for estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining means further comprises means for scaling the minimum percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled minimum percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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21. The IMD of claim 13, wherein the estimating means further comprises means for determining, from the estimated past current drain and the average measured battery voltage, a 5th percentile remaining life estimate of the time remaining during which 5% of batteries exhibiting the characteristic voltage drop of the battery voltage when subjected to the estimated past current drain of this type will fall to the elective replacement interval voltage.
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22. The IMD of claim 21, further comprising:
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adjusting means for adjusting the battery energy bolus that will be consumed during each energy consuming incident or the frequency of occurrence of energy consuming incidents per unit of time occurring in the future; and
wherein;
the estimating means further comprises means for estimating an estimated future current drain for each channel as a function of the estimated past current drain and the adjusted battery energy bolus; and
the determining means further comprises means for scaling the 5th percentile remaining life estimate based upon estimated past current drain to the ratio of the estimated past current drain and the estimated future current drain to derive a scaled 5th percentile remaining life estimate until the battery elective replacement interval voltage is reached.
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23. The IMD of claim 13, wherein:
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the IMD comprises a cardiac pacing system that delivers pacing pulses in energy consuming incidents through a pacing lead and electrode and body tissue comprising a load having an impedance, whereby delivery of each pacing pulse consumes a predetermined bolus of energy, and the estimating means further comprises means for measuring the impedance of the load.
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24. The IMD of claim 13, wherein:
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the IMD comprises an electrical stimulator that delivers stimulation pulses in energy consuming incidents through an electrode and body tissue comprising a load having an impedance, whereby delivery of each stimulation pulse consumes a predetermined bolus of energy, and the estimating means further comprises means for measuring the impedance of the load.
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25. A method of estimating remaining life of a battery that powers an implantable medical device (IMD), comprising the step of:
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obtaining a measurement indicative of voltage provided by the battery;
obtaining an estimation of past current drain on the battery; and
determining the estimated remaining life of the battery from the measurement indicative of voltage and the estimation of east current drain, wherein obtaining a measurement includes obtaining an average of multiple measurements each indicative of battery voltage.
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26. A method of estimating remaining life of a battery that powers an implantable medical device (IMD), comprising the steps of:
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obtaining a measurement indicative of voltage provided by the battery;
obtaining an estimation of past current drain on the battery;
determining the estimated remaining life of the battery from the measurement indicative of voltage and the estimation of past current drain, wherein obtaining a measurement includes obtaining a quiescent current drain;
obtaining an episodic current drain; and
adding the quiescent current drain and the episodic current drain.
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27. A method of estimating remaining life of a battery that powers an implantable medical device (IMD), comprising the steps of:
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obtaining a measurement indicative of voltage provided by the battery;
obtaining an estimation of past current drain on the battery;
determining the estimated remaining life of the battery from the measurement indicative of voltage and the estimation of past current drain;
adjusting an operating parameter of the IMD to modify IMD power consumption;
estimating a future current drain at the modified IMD power consumption; and
scaling the estimated remaining life of the battery based on the future current drain.
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28. A method of estimating remaining life of a battery that powers an implantable medical device (IMD), comprising the steps of:
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obtaining a measurement indicative of voltage provided by the battery;
obtaining an estimation of past current drain on the battery; and
determining the estimated remaining life of the battery from the measurement indicative of voltage and the estimation of past current drain, wherein determining the estimated remaining life includes determining an estimated remaining life for a predetermined maximum percentage of batteries.
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29. A method of estimating remaining life of a battery that powers an implantable medical device (IMD), comprising the steps of:
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obtaining a measurement indicative of voltage provided by the battery;
obtaining an estimation of past current drain on the battery; and
determining the estimated remaining life of the battery from the measurement indicative of voltage and the estimation of past current drain, wherein determining the estimated remaining life includes determining an estimated remaining life for a predetermined minimum percentage of batteries.
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30. A system for monitoring life of a battery, comprising:
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a sensing circuit to measure voltage provided by the battery; and
a processing circuit coupled to the sensing circuit to calculate past current drain on the battery and to further determine, based on the measured voltage and the past current drain, an estimated remaining life of the battery, wherein the processing circuit includes means for utilizing a quiescent current drain and an episodic current drain to calculate the past current drain. - View Dependent Claims (31)
a circuit to adjust an operating parameter of a system coupled to the battery to modify power consumption from the battery; and
wherein the processing circuit includes means for estimating a future current drain at a modified power consumption level, and for scaling the estimated remaining life of the battery based on the future current drain.
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Specification