Battery charge indicator for implantable pacemakers and defibrillators

摘要

Current usage from a battery in an implantable cardiac device is tracked. The apparatus includes a battery current sensor having multiple current ranges. The current sensor produces a first signal representative of current drawn from a battery. A current range selector selects a current range for the battery current sensor and produces a second signal representative of the current range. An accumulator accumulates the first signal based on the second signal over time to generate an output signal representing usage of the battery.