An Improved Signal Mixing Method Based on Tunnel Magnetoresistance-Rogowski Coil Sensors for SiC MOSFETs

Wide-band current sensors with DC capability are crucial for characterizing both steady-state and high-frequency transients in switched-mode power electronics and digital control. Traditional hybrid sensors often suffer from complex circuitry, need for precise tuning, high component count, and elevated cost. This paper presents an improved signal mixing method based on tunneling magnetoresistive (TMR) sensors and Rogowski coil sensors. By directly winding the TMR output leads into a Rogowski coil, which is the distinctive design of this work, the two signals are combined without additional complex circuitry. Using only one hybrid integrator, the proposed method achieves a bandwidth from DC to 54.9 MHz, significantly simplifying design and reducing cost. The sensor exhibits linear deviation within 2% and a resolution of 0.1 A at 5 MHz. Double-pulse tests using SiC MOSFETs further demonstrate its potential for switch transient testing of high-frequency power semiconductors.