On Chip Calibration of Hall Sensors Sensitivity

A promising method to calibrate the Hall sensors sensitivity is based on the measurement of a stable reference magnetic field, which is generated directly on-chip by an integrated metal coil excited by a stable current. A mixed signal circuitry adjusts the sensitivity according to the reference magnetic signal measurement. In this paper we present a novel scheme for the small reference field detection in presence of the external magnetic field signal. This approach achieves an accurate continuous autocalibration procedure that is invisible from the outside and active during the entire lifetime of the sensor.