Skew input offset voltage in current-sense amplifiers

Certain applications require that you calibrate the input offset voltage (V_OS) of a current-sense amplifier to enhance the accuracy of its current measurements. This calibration, however, is hampered by interactions between the amplifier's minimum output voltage (V_OL) and its input V_OS at zero current. This article presents a simple method for "skewing" the input V_OS of a unidirectional current-sense amplifier. The method lets you measure input V_OS without the usual limitations due to V_OL, and also improves the overall measurement accuracy.