Patent ID: 6700427
Filing Date: 2004-03-02
Classification: G01N,H03K

Abstract:
A machine to compensate for series resistance comprising:a) a voltage source connected to a cell through an electrode, forming a voltage clamp, said electrode comprising an electrode series resistance and an electrode current, said voltage clamp having an uncompensated time constant proportional to said series resistance and an uncompensated bandwidth inversely proportional to said series resistance, and b) a standard series resistance compensation signal proportional to said electrode current, and c) a filter means to attenuate said compensation signal, said filter means having a filter input equal to said compensation signal and a filter output, said filter output being added to said voltage source to supply positive feedback to said voltage clamp, said filter means having a lowpass frequency response including: i) a corner frequency, said corner frequency being lower in value than said uncompensated bandwidth, ii) a roughly unity gain at frequencies below said corner frequency, iii) an increasing attenuation, said increasing attenuation beginning at frequencies roughly equal to said corner frequency and ending at frequencies roughly equal to the value of said compensated bandwidth, and iv) a roughly constant attenuation at frequencies higher in value than said uncompensated bandwidth, wherein said feedback lowers the value of said uncompensated time constant to a compensated time constant and increases the value of said uncompensated bandwidth to a compensated bandwidth, andwherein said filter means enhances the stability of said positive feedback.