Integrating GMR Field Detectors for High-Bandwidth Current Sensing in Power Electronic Modules

This paper analyzes the placement of giant magnetoresistive (GMR) field detectors in power electronic modules. GMR field detectors can provide simultaneous high-bandwidth (dc to megahertz) current and temperature measurements in a small area (1.26 $\hbox {mm}^{2}$ ). 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 the placement of the GMR detectors. One significant contribution of this paper is to identify the effects of a 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 the 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.