Evaluation of Point Field Sensing in IGBT Modules for High Bandwidth Current Measurement

This paper evaluates field-based current sensing integration in power electronic modules. Point field detectors, such as GMR detectors, can provide high bandwidth (DC to MHz) current measurements with a small footprint (1.26 mm(2)). Magnetic fields surrounding a current carrying conductor are frequency dependent, so the 5% Flat Bandwidth (FBW) metric is used to evaluate placement of the point field detectors to maximize the bandwidth of the current measurement. A significant contribution of this paper is an evaluation of the placement of point field detectors inside a power switching module. The paper focuses on detector placement for the interconnect structures commonly found in power switching modules. Experimental and finite element analysis of wire bond structures with multiple wire bonds and lead frame structures are evaluated for high bandwidth sensing performance.