MAGNETIC SENSOR CONTROL CIRCUIT AND MAGNETOMETRIC FIELD MEASURING DEVICE

PROBLEM TO BE SOLVED: To attain both high-resolution and high-accuracy measurement and extension of dynamic range in a magnetic field device. SOLUTION: Within the measurement range of magnetic field that is set in the linear area of input/output characteristic of a magnetometric sensor 8, an ADC comprised of a ΔΣ modulator 22 and a digital filter 24 converts the output of the magneto sensor 8 into magnetic field measurement data DMwith high resolution. A bias magnetic field is applied to the magnetometric sensor 8 through a coil 10 so as to shift the measurement range of magnetic field. Driving current given to the coil 10 is discretely changed by current DAC 28. The moving step of magnetic field measurement range caused by a change in bias magnetic field is set larger than the resolution of magnetic field strength by the ADC. COPYRIGHT: (C)2010,JPO&INPIT