Two-demensional magnetic sensors

Abstract

The patent relates to a two-dimensional magnetic sensor to detect the external magnetic field, which is characterized in comprising a first MI element disposed to detect the component in the direction of the first coordinate axis, which is composed of a first induction magnetic body with length below 2mm and a first electromagnetic coil wound around the periphery of the induction magnetic body; a second MI element disposed to detect the component in the direction of the second coordinate axis, which is composed of a second induction magnetic body with length below 2mm and a second electromagnetic coil wound around the periphery of the induction magnetic body; an integrated circuit having the oscillation means to provide the pulse current or high-frequency current; a switch means to alternatively supplying current to the first MI element and the second MI element; a detection means to detect the output voltage of each electromagnetic coil of the first MI element and the second MI element; and an amplifier to amplify the output voltage of said detection means. According to the invention, the two-dimensional magnetic sensor which boasts a wide magnetic field measurability range, low power consumption, and an extremely small size.

Description

(1) Technical field [0001] The invention relates to a high-sensitivity two-dimensional magnetic sensor for detecting geomagnetism and the like. (2) Background technology [0002] Regarding a magnetic field detection device for detecting geomagnetism, an invention using a high-sensitivity MI element is disclosed in JP-A-2001-296127. In the invention described in the document, MI elements are arranged in the directions of two coordinate axes, a negative feedback circuit is used, and temperature compensation is performed through a differential circuit. [0003] On the one hand, in view of the rapid development of mobile devices including mobile phones in recent years, an ultra-small and power-saving electronic compass is required in terms of portability. For an electronic compass, a two-dimensional high-sensitivity magnetic sensor is required. [0004] Such a magnetic sensor is required to have a range in which the intensity of the magnetic field can reach a linear output vol...

AI Technical Summary

Problems solved by technology

[0006] The technique described above uses two MI elements in the direction of one coordinate axis, uses a differential circuit for the difference calculation of these two signals, and uses a negative feedback circuit to increase the scale of the electronic circuit, which is not suitable for small change

Also, due to the expansion of the possible range of magnetic measurement and the increase of power consumption due to the flow of negative feedback current

[0007] And the size of the original MI component is large: its width is 3mm, height is 2mm, and length is 4mm, so it is difficult to apply to small electronic devices

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