Efficient External Charger for an Implantable Medical Device Optimized for Fast Charging and Constrained by an Implant Power Dissipation Limit

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;
• 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.

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;
• 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.

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;
• 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.

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.

A method for programming an external charger to ensure compliance with a power dissipation limit for an implantable medical device during charging, comprising:

• 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.