An Approach to On-Trace Current Sensing Scheme With Switching Noise Immunity

Magnetoresistance (MR) current sensors have gained increasing attention due to their compact size and high accuracy. However, their performance degrades when exposed to high dv/dt switching noise, a common condition in wide-bandgap power converters. This letter presents a hybrid sensing approach that combines a tunnel MR sensor mounted directly on the current-carrying trace with a printed circuit board (PCB)-embedded Rogowski coil and conditioning circuits to address two major challenges: noise immunity and bandwidth limitation. This configuration extends the measurable bandwidth and mitigates dv/dt-induced transients associated with fast switching events in GaN dc–dc converters. The hybrid sensor can be flexibly placed on or near switching nodes, significantly simplifying component placement and PCB layout. Experimental results from a GaN dc–dc converter demonstrate the effectiveness of the proposed approach.