Two-axis magnetometer using circular parallel-field Hall microsensor for contactless angle measurement

A new two-axis magnetometer for in-plane magnetic field measurement consisting of a circular parallel-field CMOS Hall-effect microsensor, biasing and signal conditioning circuits has been developed and tested. The sensing device contains a narrow n-well ring with a chain of 32 contacts spaced at regular intervals along the ring´s circumference. The output magnetometer signal is a sine wave function. The magnitude of the in-plane magnetic field is directly proportional to the sine amplitude and the phase corresponds to the angle between the applied magnetic field and a reference direction. The signal conditioning electronics in hybrid implementation suppresses dynamically offset and low frequency 1/f noise.