Patent ID: 6472847
Filing Date: 2002-10-29
Classification: G01R,G06F,H01M,H04W,Y02D,Y02E

Abstract:
A battery operable electrical device comprising:a clock frequency generator operable to generate electrical signals with a predetermined clock frequency; a first electrical circuit adapted to perform a first function utilizing the electrical signals generated by the clock generator; a second electrical circuit adapted to generate an electrical excitation signal derived from the electrical signals generated by the clock generator, the excitation signal having an excitation frequency derived from the clock frequency, means for feeding the excitation signal to battery terminals of the device, wherein the second electrical circuit is adapted to receive, from a battery connected to the battery terminals, an electrical signal in response to the excitation signal, and to analyze a received signal for the battery impedance at the excitation frequency and, based on the battery impedance, to estimate the state-of-charge of the battery.