Applying magnetoresistive current sensors in difficult operating environments

Abstract:
There is a wide variety of different applications in the field of power electronics where electrical currents need to be measured. However, the requirements for these measurement devices are becoming steadily more demanding regarding accuracy, size and especially bandwidth. Highly integrated current sensors based on the magnetoresistive effect, such as the CFS1000 family (Fig. 1), possess many advantages compared to current sensors based on hall-effect or shunts. A combination of high precision, wide bandwidth, inherent galvanic isolation and small size have led to a strong increase in the range of applications. There are, however, additional demands due to more difficult operating conditions. A number of current trends in the field of power electronics e.g. higher integration, higher power density, higher switching frequencies in association with wide-band-gap power transistors, as well as higher efficiency, are generating new requirements for magnetically-based current sensors. In addition to product adaptations these new trends also necessitate the use of new tools and methods to ensure safe and stable operation in challenging operating environements.