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 giant magnetoresistor detectors, can provide high-bandwidth (dc to megahertz) current measurements with a small footprint (1.26 mm2). Magnetic fields surrounding a current-carrying conductor are frequency dependent, so the 5 % flat-bandwidth 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. This 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.