A new current sensor based on the Miller effect highly immune to EMI

Abstract

This paper deals with the susceptibility to electromagnetic interference (EMI) of circuits used in smart power integrated circuits to sense the current of power transistors. The susceptibility of a conventional current sensor based on the mirroring principle is first investigated. Then a new circuit that avoids the electrical connection of the current sensor to the power transistor drain terminal is proposed. The susceptibility of the above mentioned current sensors is discussed and evaluated by means of time-domain computer simulations.