초록 ▼

There is provided an implantable device system such as a battery-powered pacemaker system, with an improved capability of measuring battery internal impedance, thereby providing the means to determine anticipated device End of Life. Within one pacemaker cycle following a sensed beat or a delivered s

There is provided an implantable device system such as a battery-powered pacemaker system, with an improved capability of measuring battery internal impedance, thereby providing the means to determine anticipated device End of Life. Within one pacemaker cycle following a sensed beat or a delivered stimulus, and before delivery of a next stimulus, three battery measurements are taken at equally spaced time intervals. Due to the RC nature of the battery internal impedance, the first two battery voltage measurements can be used to calculate what the voltage would be at the third time, assuming no change in current load. At the third time, a predetermined incremental current load is added, and the battery voltage at the time of the added current load is measured. The voltage differential between the calculated battery voltage and the measured battery voltage at the third time, together with the predetermined incremental current load, is used to calculate the battery impedance.

대표청구항 ▼

[ What is claimed is:] [1.] An implantable device for generating and delivering stimulus pulses to a location in a patient's body, having a battery which provides energy to said device, said battery having an internal impedance which changes with cumulative expenditure of energy, a controllable puls

[ What is claimed is:] [1.] An implantable device for generating and delivering stimulus pulses to a location in a patient's body, having a battery which provides energy to said device, said battery having an internal impedance which changes with cumulative expenditure of energy, a controllable pulse generator for generating said stimulus pulses, said device further having impedance means for measuring said battery impedance, said impedance means comprising:voltage means for measuring the voltage output of said battery;timing means operative following a delivered stimulus pulse for timing a sequence of measuring times which occur before a next delivered stimulus pulse;a predetermined test load, and connecting means for connecting said test load across said battery at one of said measuring times of said sequence;triggering means for triggering said voltage means to measure said battery voltage output at each of said measuring times; andcalculating means for calculating the battery impedance as a function of the battery voltages measured at each of said measuring times.