Calibration scheme for a new type of 3D Hall sensor

Abstract 3D Hall sensors generally suffer from cross-sensitivity among measurement axes, which limits their accuracy compared to 1D Hall sensors, and complicates their calibration. To overcome these issues, a time-effective and intuitive calibration and field reconstruction method is proposed which is well-suited, but not limited, to a new type of 3D Hall sensor (“Hallcube”) consisting of six orthogonally arranged 1D Hall sensors that form a sub-millimeter active volume, and pairwise compensate for the planar Hall effect. Generally, the method is applicable to 3D Hall sensors that are composed of separate 1D Hall sensors, and show negligible planar Hall voltage (inherently or after compensation). The method is based on a two-step calibration scheme: (1) determination of the relative placement of the six constituent Hall sensors, and (2) calibration of each of the six sensors analogously to a standard 1D Hall sensor calibration. From the normal vectors and the voltage-to-magnetic-field characteristic of each sensor, the full magnetic field vector can be reconstructed. The proposed method was applied to the first prototype Hallcube sensor which achieved an accuracy of 800 ppm at the 1 T level for any direction of the field vector. The accuracy-limiting factor was the underperformance of the 1D Hall sensors, whose Hall voltages display a long-term instability of >600 ppm.