초록 ▼

An improved apparatus and method are described for providing a measurement of the charge depleted from a battery used in an implantable device such as a cardiac pacemaker. The measurement is provided not by measuring the voltage level or impedance of the battery, but rather by continuously measuring

An improved apparatus and method are described for providing a measurement of the charge depleted from a battery used in an implantable device such as a cardiac pacemaker. The measurement is provided not by measuring the voltage level or impedance of the battery, but rather by continuously measuring the electrical current drawn from the battery and integrating that measured current over an integration time period. A precision current-sensing resistor provides a sense signal having a voltage that varies according to the magnitude of current being drawn, and this sense signal is integrated using a voltage-controlled oscillator circuit and counter, which are implemented using CMOS circuitry arranged in a switched-capacitor topology.

대표청구항 ▼

[ What is claimed is:] [1.] A battery charge meter for use in monitoring the amount of charge delivered by a battery in an implantable device comprising:a sensor coupled to the battery, for providing a sense signal corresponding to the electrical current being drawn from the battery;a voltage-contro

[ What is claimed is:] [1.] A battery charge meter for use in monitoring the amount of charge delivered by a battery in an implantable device comprising:a sensor coupled to the battery, for providing a sense signal corresponding to the electrical current being drawn from the battery;a voltage-controlled oscillator circuit that generates a VCO signal having a frequency that corresponds to the sense signal; anda counter that counts the cycles of the VCO signal to produce a measurement of depleted battery charge.