Patent ID: 6577135
Filing Date: 2003-06-10
Classification: G01R,H01M,H02J,Y02E

Abstract:
A battery monitoring circuit for monitoring current through a sense resistor disposed in series with one terminal of the battery by detecting the voltage across the sense resistor, comprising:a voltage/frequency converter for converting the voltage across the sense resistor to a pulse stream, the rate of said pulse stream corresponding to the voltage across the sense resistors; a circuit for determining the current through the terminal battery with the pulse stream, the current being a function of the rate of the pulse stream; and said voltage/frequency converter having a differential structure associated therewith, said differential structure having: a first differential leg having passive switching elements and active elements associated therewith for receiving as an input voltage the voltage that is across the sense resistor and outputting a first differential signal, a second differential leg having passive switching elements and active elements associated therewith for receiving on an input the voltage across the sense resistor and outputting a second differential voltage, and a multiplex circuit for periodically switching select portions of said switching elements and passive active elements between said first and second differential legs to compensate for errors integral therewith.