Patent ID: 7751891

Claim:
An implantable medical device, comprising: an energy storage device to provide power for an operation performed by said implantable medical device, characterized by a total available electrical charge defined by the difference between an initial electrical charge and a final electrical charge; a stimulation unit, operatively coupled to said energy storage device for providing a stimulation signal; a memory adapted to store an active charge depletion rate determined during a calibration process and an inactive charge depletion rate determined during the calibration process; and a controller operatively coupled to said stimulation unit and said energy storage device, said controller comprising: an active charge depletion determination unit adapted to determine an electrical charge depleted from said energy storage device during stimulation operations of the implantable medical device based upon said active charge depletion rate and a predetermined current associated with said stimulation signal; an inactive charge depletion determination unit adapted to determine an electrical charge depleted from said energy storage device during inactive periods based upon said inactive charge depletion rate and inactive periods of the implantable medical device; and an end of service determination unit adapted to determine a time period until an end of service of said energy storage device based upon said total available electrical charge, said active charge depletion, and said inactive charge depletion.