Electronic compass sensor

Abstract

In this paper, we describe a new two respective three axis integrated IMC Hall-ASIC that can be used as a single chip electronic compass and applied in portable low cost electronic equipment like wrist watches and mobile phones. The electronic compass chip consists of ring shaped integrated ferromagnetic concentrators (IMC), a CMOS integrated circuit and an excitation coil manufactured by direct bonding onto the chip surface. The IMC Hall ASIC measures the two in-plane magnetic field components Bx and By and the vertical component Bz of the Earth's magnetic field. The IMC Hall sensor exhibits an excellent sensitivity of 8000 V/T for the X and Y axis which yields an in-plane heading accuracy of +/-1/spl deg/, whereas the field in the Z-axis is measured with a lower sensitivity of 800 V/T. The high sensitivity characteristics are obtained by integrating magnetic flux concentrators directly on the Hall-ASIC, which amplifies the Earth's magnetic field by a factor of 10. Furthermore, the compass sensors provides a low energy method to eliminate the perming effect (remnant field effect after subjecting to strong magnetic fields).