Integrating giant magneto-resistive (GMR) field detectors for high bandwidth current sensing in power electronic modules

This paper analyzes the placement of giant magneto-resistive (GMR) field detectors in power electronic modules. GMR field detectors can provide simultaneous high bandwidth (DC to MHz) current and temperature measurements in a small area (1.26 mm²). The GMR detects incident magnetic fields, and because the spatial magnetic field from current carrying conductors is dependent on frequency, a precise 5% Flat Bandwidth (FBW) metric is used to evaluate placement of the GMR detectors. One significant contribution of this paper is to identify the effects of conducting material near a current carrying conductor on the FBW performance, and to propose a methodology to achieve high FBW performance inside a power electronics module where conducting material is near the current carrying conductor. This paper also introduces a method using multiple GMR detectors to reduce the placement tolerances of the GMR detectors.