Design, fabrication, and characterization of giant magnetoresistance (GMR) based open-loop current sensor with U-shaped current carrying conductor

•Thermally compensated, open-loop current sensor based on giant magnetoresistance (GMR) effect in magnetic multilayers.•A permanent magnet bias method for converting unipolar GMR characteristics to linear bipolar characteristics.•Linear output in the current range of±50 A over operating temperature range of - 40 °C to 125 °C with linearity error less than±0.2 % and - 3 dB frequency response at 7.5 kHz.•The total error is less than 1 % F.S. over the operating temperature range of - 25 °C to 105 °C. [Display omitted] In this work, an open-loop current sensor based on giant magnetoresistance (GMR) effect in magnetic multilayered systems was designed and developed. The whole design of the current sensor consisting of a magnetic field sensing element, a current-carrying conductor, a permanent magnet, and a magnetic shield was conceptualized through FEM analyses. The simulated model was then replicated into a prototype device and the output characteristics were investigated thoroughly under different ambient conditions. It was observed that in an analog mode, the sensor output was linear in the current range of± 50 A over the temperature range of − 40 °C to 125 °C and showed a − 3 dB frequency response at 7.5 kHz. A thermal drift and offset were observed at the analog output which further compensated through a commercial mixed-signal conditioner. The compensated output showed a total error less than 1% F.S. over the operating temperature range of − 25 °C to 105 °C.