A high-sensitivity current-shunt monitor with extended input common-mode voltage range

Abstract

This paper presents an effective design solution for a high-sensitivity current-shunt monitor which operates with an independent supply voltage from 5 to 16 V and achieves a wide input common-mode voltage range from −16 to 60 V. The proposed current-shunt monitor adopts two amplifiers, a current source and several resistors to constitute a feedback circuit and successfully sense drops across shunt at common-mode voltages from −16 to 60 V. The sensing current was magnified by using a current-mirror circuit and a linear regulator. The proposed architecture has been implemented in a VIS-0.25μm BCD technology and its performances have been confirmed by simulation. The simulation results show that the current-shunt monitor can sense an input voltage difference between 4 and 16 mV and keeps a constant scaled gain of 100V / V where the input CM voltage varies from −16 to 60 V.