Magnetoresistance-based Current Sensor for Wide Bandgap Power Converter Integration Applications

With the rapid growth of wide bandgap power converters in high power-density applications, current sensors play an increasingly critical role in ensuring precise control and protection. In these compact designs, maintaining low-power signal integrity becomes challenging due to the extremely fast switching speeds, whether hard or soft-switched. This work provides a detailed analysis of the performance of contactless magnetic field detectors for current measurement in such noisy environments. A novel processing technique is proposed to enable the integration of high-performance magnetoresistors (MR) in high-frequency wide bandgap power converters. An early prototype is designed and experimentally evaluated using a tunnel magnetoresistor (TMR) detector. Effectiveness of the proposed solution is demonstrated through the accurate detection of the switch node current of a gallium nitride (GaN) converter operating at a 500 kHz switching frequency.