JPH06174409A - Magnetic rotation sensor - Google Patents

Abstract

PURPOSE:To improve the yield of an MR element and reduce the chip size. CONSTITUTION:A resistor R1 and an MR element M1 are made a pair, a resistor R2 and an MR element 2 are made a pair, and outputs are extracted from individual connection points. The resistor R1 is selected to be matched with the characteristic of the MR element M1. The resistor R2 is selected to be matched with the characteristic of the MR element M2. The resistor can be adjusted, the dispersion of the characteristic of the MR element is allowed, and the yield can be improved. Only two MR elements are required to be arranged, and the chip size can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic rotation sensor, and more particularly to a magnetic rotation sensor using an MR element.

[0002]

2. Description of the Related Art FIG. 5 is a cross-sectional view of an essential part of an example of a conventional magnetic rotation sensor. The magnetic rotation sensor 51 has a configuration in which the MR elements M1, Ma, Mb, M2 are arranged in a line on the upper surface of the substrate B. MR elements M1, Ma, Mb, M2
The arrangement pitch is 1 / pitch of the rotating magnetic gear G
It is 2.

FIG. 6 is a circuit diagram of the magnetic rotation sensor 51. The MR element M1 and the MR element Ma, which are separated by 1/2 the pitch of the magnetic gear G, form a pair, and the MR element Mb and the MR element M2, which are also separated by 1/2 the pitch of the magnetic gear G, form a pair. An A-phase output and a notA-phase output are taken out from each connection point in pairs.

FIG. 7A is a schematic waveform diagram of the A-phase output when the magnetic gear G rotates in the CW direction (or CCW direction). In addition, V0 shows a neutral voltage. The MR elements M1, Mb (and the MR elements Ma, M2) are separated by one pitch of the magnetic gear G, and the MR elements M1, Mb
Since the positional relationship between a and the MR elements Mb and M2 is reversed, the A-phase output and the notA-phase output have opposite phases. FIG. 7B shows a schematic waveform diagram of the notA phase output. Therefore, the differential signal between the A-phase output and the notA-phase output has a waveform as shown in FIG.

[0005]

In the above conventional magnetic type rotation sensor 51, in order to eliminate the offset of the differential signal, the neutral voltage V0 of the A phase output and the not A phase output is set to Vc.
It is necessary to adjust to c / 2. Therefore, it is necessary to combine two MR elements having the same magnetic field strength-resistance characteristics, and there is a problem that the yield of the MR elements is low. Further, in the above conventional magnetic rotation sensor 51, on the upper surface of the substrate B,
Since the four MR elements Ma, M1, Mb, and M2 are arranged at an arrangement pitch that is 1/2 the pitch of the magnetic gear G, there is a problem that the chip size becomes large.

Therefore, an object of the present invention is to provide a magnetic rotation sensor capable of improving the yield of MR elements and reducing the chip size.

[0007]

In the magnetic rotation sensor of the present invention, the MR element M1 and the MR element M2 are arranged in parallel with the rotation direction of the object to be detected, and the MR element M1 and the resistor R1 are connected in series. Is connected between the power supply line and the Gnd line, and the series connection of the MR element M2 and the resistor R2 is connected to the power supply line-
It is characterized in that the output signals are taken out between the MR element M1 and the resistor R1 and between the MR element M2 and the resistor R2, respectively, by connecting between the Gnd lines.

[0008]

In the magnetic rotation sensor of the present invention, the MR element M
Since the output signal is taken out from the series circuit of 1 (or MR element M2) and resistor R1 (or resistor R2), the neutral voltage can be adjusted freely by selecting a resistor that matches the magnetic field strength-resistance characteristics of the MR element. Therefore, the allowable range of variations in the characteristics of the MR element is widened, and the yield of the MR element can be improved. Moreover, since only two MR elements M1 and M2 need to be arranged, the chip size is reduced.

[0009]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. The present invention is not limited to this.

First Embodiment FIG. 1 is a sectional view of the essential parts of a magnetic type rotation sensor according to the first embodiment of the present invention.

The magnetic rotation sensor 1 has a structure in which MR elements M1 and M2 are arranged on the upper surface of a substrate B. The arrangement interval of the MR elements M1 and M2 is 1/2 of the pitch of the rotating magnetic body gear G. FIG. 2 is a circuit diagram of the magnetic rotation sensor 1. In this magnetic rotation sensor 1, the resistor R1 and the MR element M1 form a pair, and the resistors R2 and M similarly.
The R element M2 forms a pair, and the A phase output and the notA phase output are taken out from the respective connection points. The resistor R1 is selected so that the minimum value of the A-phase output is Vcc / 2. Further, the resistor R2 is selected so that the maximum value of the notA phase output becomes Vcc / 2.

FIG. 3A is a schematic waveform diagram of the A-phase output when the magnetic gear G rotates in the CW direction (or CCW direction). Since the arrangement interval between the MR element M1 and the MR element M2 is 1/2 the pitch of the magnetic gear G, no
The tA-phase output has the opposite phase to the A-phase output. FIG. 3B
A schematic waveform diagram of the notA phase output is shown in FIG. Therefore, the differential signal between the A-phase output and the notA-phase output is (c) in FIG.
The waveform is as shown in.

According to the first embodiment, the allowable range of variations in the characteristics of the MR element is widened, and the yield of the MR element can be improved. Also, on the upper surface of the substrate B, MR
Element M1 and MR element M2 (arrangement interval is 1 / pitch of pitch
Since only two of 2) need to be arranged, the chip size becomes small.

-Second Embodiment- FIG. 4 is a view of a magnetic rotation sensor according to a second embodiment of the present invention, which corresponds to FIG. The magnetic rotation sensor 31 has substantially the same configuration as the magnetic rotation sensor 1 according to the first embodiment, but variable resistors VR1 and VR2 are used instead of the resistors R1 and R2.

According to the second embodiment, in addition to the effect of the first embodiment, by finely adjusting the variable resistors VR1 and VR2, the minimum value of the A phase output and the maximum value of the notA phase output are obtained. Can be easily adjusted to Vcc / 2.

[0016]

According to the magnetic type rotation sensor of the present invention,
The yield of the MR element can be improved. In addition, the chip size can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a magnetic rotation sensor according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of the magnetic rotation sensor shown in FIG.

FIG. 3 is a phase A output of the magnetic rotation sensor of FIG. 1, notA
It is a typical waveform diagram of a phase output and a differential output.

FIG. 4 is a cross-sectional view of essential parts of a magnetic rotation sensor according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a conventional magnetic rotation sensor.

6 is a cross-sectional view of the main parts of the magnetic rotation sensor of FIG.

7 is a phase output of the magnetic rotation sensor of FIG. 5, notA
It is a typical waveform diagram of a phase output and a differential output.

[Explanation of symbols]

 1, 31, 51 Magnetic rotation sensor M1, M2, Ma, Mb MR element R1, R2 resistance VR1, VR2 variable resistance G magnetic gear B substrate Vcc power supply voltage

Claims (1)

[Claims] 1. An MR element M1 and an MR element M2 are arranged in parallel with a rotation direction of an object to be detected, and a series connection of the MR element M1 and a resistor R1 is connected between a power supply line and a Gnd line. A series connection of the element M2 and the resistor R2 is connected between the power supply line and the Gnd line, and the MR element M2 and the resistor R2 are connected between the MR element M1 and the resistor R1.
A magnetic rotation sensor characterized in that output signals are taken out from between and.