High precision current-shunt monitor with extended input common-mode voltage range

Abstract

This paper presents a design solution for a high precision current-shunt monitor allowing input common-mode levels from -0.3V to 30V, independent of the supply voltage. The maximum referred to input offset voltage is ±10μV, over the entire common-mode input range. The proposed configuration has a fixed gain of 200 and exhibits a maximum gain error of 0.1%. The supply voltage can vary between 2.6V and 30V. The circuit has been designed in a 0.25μm BCD technology with a die area of only 0.8mm2.