BG111066A - A two-axle magnetometer - Google Patents

Abstract

The two-axle magnetometer contains a semiconducting padding with p-type conductivity (1) on the one side of which a deep n-type region (2) is created in the shape of a circle. On the upper side of the region (2), along its periphery, a number of 2k ohmic n+-contacts are positioned at equal distances one from another, where k is an integer, and in its centre there is one more ohmic n+-contact (3)connected with one terminal of the current source (4). Each one of the peripheral contacts can be found in one of the two positions: to be switched on to an interface circuit or to be pendant. At everyone moment of time only the contact (3) and the two diametrically opposite peripheral contacts (5) and (6) are active, while the rest 2k - 2 contacts are pendant. The specified in such a way three-contact configuration (3), (5) and (6) forms a Hall microsensor with a parallel sensitivity axis, this microsensor being able to measure the magnetic field (7) situated along the plane of the padding (1). The two opposite contacts (5) and (6) are at one and the same time output and terminal, inasmuch through equal value resistors (8) and (9) they are connected to the other terminal or the power source (4). The interface circuit contains two multiplexors (10 and 11) each one of them having a number of 2k inputs, a timing generator (12) of fixed operational frequency controlling the multiplexors (10 and 11) a counter (13),connected with the multiplexors (10 and 11), the rotation of the three-contact Hall microsensor around the axis perpendicular to the region (2) and passing through the contact (3) has a step of rotation equal to the angle between two adjacent peripheral contacts a measuring amplifier (14) whose input is connected through the two multiplexors (10 and 11) with the contacts (5 and 6) of the microsensor. The output of the amplifier (14) is connected with the input of a low-frequency filter (15) whose output is the output (16) of the magnetometer.