A Fully Integrated Chopped Hall Sensor for Gear Rotation Measurements

A contactless chopped Hall sensor is presented in this paper for various gear or magnetic ring measurement. The work exploits magnetic field intensity changes as a measured strategy of the Hall gear sensor. The sensor combines spinning current and chopping technology to decrease the Hall offset. In addition, programmable configuration enhances the sensitivity robustness for temperature drift. The digital auto-calibration adjusts the switching point dynamically even if the airgap between the detected target and sensor vibration occurs. All these techniques improve the integrated sensor accuracy and achieve nearly zero-speed detection ability. The Hall sensitivity is 88.7mV/T, and its temperature drift is kept under 3.7% from -40 to 150 °C. The effective operation airgap ups to 3.4mm in the laboratory environment. The good performance indicates that the Hall sensor has a broad prospect for high-robustness and low-cost gear measurement applications.