Improve Current Measurement Accuracy by Skewing the Input Offset Voltage on Current-Sense Amplifiers

Abstract: Some applications require that the input offset voltage (VOS) of current-sense amplifiers be calibrated to enhance measurement accuracy. This is not a straightforward task because of interactions between the output voltage low (VOL) and the input VOS. This application note outlines a simple method to artificially \"skew\" the input VOS of unidirectional current-sense amplifiers. The method allows measurement of total-input VOS without the normal limitations from VOL, and improves the overall accuracy of current measurements. The MAX4080 current-sense amplifier serves as the example of the technique.