An integrated fluxgate magnetometer for use in closed-loop/open-loop isolated current sensing

Abstract

This paper presents two integrated magnetic sensor ICs for isolated current sensing. Both employ an integrated fluxgate magnetometer with a sensitivity of 250V/T and a 500ksps readout circuit. Only 5.4mW is required to excite the sensor, which is 20x more power efficient than the state-of-the-art. With an external magnetic core, the resulting closed-loop current sensor IC achieves a dynamic range of 112dB and a non-linearity below 0.03%, while the open-loop current sensor IC has a dynamic range of 100dB and a non-linearity below 0.2%.