A 2D CMOS microfluxgate sensor system for digital detection of weak magnetic fields

Author

Kawahito, Shoji ; Maier, Christoph ; Schneiher, M. ; Zimmermann, Martin ; Baltes, Henry

Author_Institution

Dept. of Inf. & Comput. Sci., Toyohashi Univ. of Technol., Japan

Volume

34

Issue

12

fYear

1999

fDate

12/1/1999 12:00:00 AM

Firstpage

1843

Lastpage

1851

Abstract

This paper presents a CMOS two-dimensional (2-D) vector magnetic sensor system integrating two planar microfluxgate sensors and the complete electronics for sensor excitation and signal readout. The system is based on an industrial 0.8-μm double-poly, double-metal CMOS technology with ferromagnetic NiFeMo cores added in a simple postprocessing sequence. The fluxgate sensors are embedded in a ΣΔ analog-to-digital converter for a stable and precise digital detection of weak magnetic fields. A cascaded ΣΔ modulator topology is utilized to obtain second-order noise shaping and to suppress pattern noise. Within the range of ±50 μT, the system nonlinearity is less than 1.5 μT. The angular resolution as a 2D vector sensor is less than 4° for a measured magnetic induction of 50 μT. This makes the 2-D microfluxgate magnetometer suitable for use as fully integrated electronic compass

Keywords

CMOS integrated circuits; fluxgate magnetometers; magnetic cores; magnetic sensors; microsensors; sigma-delta modulation; 0.8 micron; 2D CMOS microfluxgate sensor system; 50 muT; NiFeMo; analog-to-digital converter; angular resolution; digital detection; double-poly double-metal CMOS technology; ferromagnetic NiFeMo cores; fully integrated electronic compass; magnetic induction; pattern noise; postprocessing sequence; second-order noise shaping; sensor excitation; signal readout; system nonlinearity; vector magnetic sensor system; weak magnetic fields; Analog-digital conversion; CMOS technology; Magnetic cores; Magnetic field measurement; Magnetic noise; Magnetic sensors; Noise shaping; Sensor systems; Topology; Two dimensional displays;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.808909

Filename

808909