Battery operable device with battery state-of-charge indicator

Abstract

A battery operable electrical device, such as a mobile telephone or a laptop computer, with a clock frequency generator operable to generate electrical clock frequency signals, and a first electrical circuit adapted to perform a first or main function of the device, utilizing the clock frequency signals generated by the clock generator. The device further includes a second electrical or auxiliary circuit adapted to generate an electrical excitation signal with an excitation frequency derived from the clock frequency signals. The excitation signal is fed to battery terminals of the device, and the second electrical circuit receives, from a battery connected to the battery terminals, an electrical signal in response to the excitation signal, and to analyze the received signal for the battery impedance at the excitation frequency and, based on the battery impedance, the state-of-charge of the battery is estimated.

Dependencies are inferred from the claim text.