Efficient External Charger for an Implantable Medical Device Optimized for Fast Charging and Constrained by an Implant Power Dissipation Limit
First Claim
1. A method for charging a battery in an implantable medical device, comprising:
- generating a magnetic charging field using an external charger, the magnetic charging field for producing a battery charging current in the implantable medical device during a charging session;
periodically measuring during the charging session a parameter in the implantable medical device;
periodically telemetering during the charging session the parameter to the external charger; and
periodically adjusting during the charging session the magnetic charging field in accordance with the parameter to maximize the produced battery charging current while not exceeding a maximum power dissipation limit for the implantable medical device.
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Accused Products
Abstract
An improved external charger for a battery in an implantable medical device (implant), and technique for charging the battery using such improved external charger, is disclosed. In one example, simulation data is used to model the power dissipation of the charging circuitry in the implant at varying levels of implant power. A power dissipation limit is chosen to constrain the charging circuitry from producing an inordinate amount of heat to the tissue surrounding the implant, and duty cycles are determined for the various levels of input intensities to ensure that the power limit is not exceeded. A maximum simulated average battery current determines the optimal (i.e., quickest) battery charging current, and at least an optimal value for a parameter indicative of that current, for example, the voltage across the battery charging circuitry, is determined and stored in the external charger. During charging, the actual value for that parameter is reported from the implant to the external charger, which in turn adjusts the intensity and/or duty cycle of the magnetic charging field consistent with the simulation to ensure that charging is as fast as possible, while still not exceeding the power dissipation limit.
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Citations
32 Claims
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1. A method for charging a battery in an implantable medical device, comprising:
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generating a magnetic charging field using an external charger, the magnetic charging field for producing a battery charging current in the implantable medical device during a charging session; periodically measuring during the charging session a parameter in the implantable medical device; periodically telemetering during the charging session the parameter to the external charger; and periodically adjusting during the charging session the magnetic charging field in accordance with the parameter to maximize the produced battery charging current while not exceeding a maximum power dissipation limit for the implantable medical device. - View Dependent Claims (2, 3, 4, 5)
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6. A method for charging a battery in an implantable medical device, comprising:
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generating a magnetic charging field using an external charger, the magnetic charging field for producing a battery charging current in the implantable medical device; measuring a parameter in the implantable medical device indicative of the produced battery charging current; telemetering the parameter to the external charger; comparing a value of the telemetered parameter to an optimal value at the external charger, wherein the optimal value indicates a maximum average battery current; and adjusting the magnetic charging field in accordance with the comparison in a manner not to exceed a power dissipation limit for the implantable medical device. - View Dependent Claims (7, 8, 9, 10)
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11. A method for charging a battery in an implantable medical device, comprising:
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generating a magnetic charging field using an external charger, the magnetic charging field for producing a battery charging current in the implantable medical device; measuring a parameter in the implantable medical device indicative of the produced battery charging current; telemetering the parameter to the external charger; consulting data stored in the external charger which relates values of the parameter to a duty cycle for the external charger; determining a duty cycle from the data for a value of the telemetered parameter; and duty cycling the magnetic charging field in accordance with the determined duty cycle. - View Dependent Claims (12, 13, 14, 15)
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16. A method for charging a battery in an implantable medical device, comprising:
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generating a magnetic charging field using an external charger, the magnetic charging field for producing a battery charging current in the implantable medical device; measuring a parameter in the implantable medical device; telemetering the parameter to the external charger; and adjusting an intensity and duty cycle of the magnetic charging field in response to the telemetered parameter, wherein the adjustment ensures a power dissipation limit for the implantable medical device is not exceeded. - View Dependent Claims (17, 18, 19, 21)
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20. (canceled)
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22. An external charger designed to ensure compliance with a power dissipation limit for an implantable medical device during charging of a battery in the implantable medical device, comprising:
a memory in which is stored; a first relationship between values for (i) a parameter measureable in the implant, and (ii) a duty cycle for the external charger, wherein the duty cycles ensure that the power dissipation limit is not exceeded; and a first optimal value for the parameter in the external charger, wherein the first optimal value is indicative of a maximum battery charging current. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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29. A method for programming an external charger to ensure compliance with a power dissipation limit for an implantable medical device during charging, comprising:
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determining an external charger duty cycle and an average battery charging current for a plurality of external charger intensities, wherein the duty cycles are determined such that the implantable medical device does not exceed the power dissipation limit; determining a parameter measureable in the implantable medical device which is indicative of the average battery charging current; determining a maximum average battery current and a corresponding optimal value for the parameter; storing a relationship between the parameter and the duty cycles in the external charger; and storing the optimal value for the parameter in the external charger. - View Dependent Claims (30, 31, 32)
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Specification