JPH04279071A - Hall element - Google Patents

Abstract

PURPOSE:To bring an unbalanced voltage closer to 0>>V as much as possible so as to reduce the offset when the density of magnetic fluxes produced by a Hall element is measured in the form of analog values. CONSTITUTION:An unbalanced voltage is adjusted so that the voltage can become the minimum by providing a plurality of by-passes 22-25 or taps in the magnetism sensible section 12 of a Hall element 11 and disconnecting such by-passes 22-25 or taps.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Hall element, and more particularly to a structure for reducing unbalanced voltage of the Hall element.

0002

[Prior Art] FIG. 3 shows a typical conventional Hall element 1.
It is shown.

The Hall element 1 generally includes a magnetically sensitive portion 2 made of a cross-shaped thin film. A pair of input terminals 3 and 4 are connected to a pair of ends facing each other in the first direction among the ends of the four protrusions of the magnetically sensitive portion 2, and the other end is connected to the above-mentioned A pair of output terminals 5 and 6 are respectively connected to a pair of ends facing in a second direction that intersects (more specifically, orthogonally) in one direction.

In the Hall element 1 having such a structure,
A voltage is applied from the power supply 7 between the pair of input terminals 3 and 4, thereby causing a current to flow between the pair of input terminals 3 and 4, and applying a magnetic field in a direction perpendicular to the current. , an electromotive force VH is generated between output terminals 5 and 6. This VH is called a Hall voltage, and as shown in FIG. 4, this Hall voltage VH generally has a proportional relationship to the magnetic flux density B of the magnetic field described above.

[0005]

[Problem to be Solved by the Invention] In such a Hall element 1, if the magnetically sensitive portion 2 has ideal symmetry, even if a current is passed between the input terminals 3 and 4, the magnetic field When is 0, no potential difference appears at output terminals 5 and 6, and the voltage becomes 0 [V]. However, in reality, even when the magnetic field is 0, the output terminal 5
A potential difference appears at and 6. This potential difference is called an unbalanced voltage VHO, and when such an unbalanced voltage VHO occurs, the Hall voltage VH as shown by the solid line in FIG.
is output from between output terminals 5 and 6.

[0006] When used digitally, such as the Hall element used in brushless motors,
Even if an unbalanced voltage occurs, it does not pose a particular problem. On the other hand, when used in analog applications such as Hall elements used in position sensors, unbalanced voltages cause errors and accurate measurement becomes impossible. In recent years, demand for such Hall elements for analog applications has been increasing.

[0007] Conventionally, therefore, offset adjustment is performed using a signal processing circuit to cancel the unbalanced voltage, but there are problems such as an increase in the cost of the circuit, difficulty in miniaturization, and troublesome adjustment. .

[0008]Also, there are cases where the magnetically sensitive part of the Hall element is trimmed using a laser or the like to reduce the unbalanced voltage, but in this case, impurities such as combustion substances may adhere to the trimmed part. Problems such as , affecting performance such as temperature characteristics, etc. have occurred.

Therefore, an object of the present invention is to reduce the unbalanced voltage to 0[V] as much as possible without using the above-mentioned means.
] The purpose of the present invention is to provide a Hall element that can be brought close to .

0010

[Means for Solving the Problems] This invention provides a magnetically sensitive portion,
a pair of input terminals respectively connected to a pair of first ends opposite to the first direction of the magnetically sensitive portion, and a second direction of the magnetically sensitive portion that intersects with the first direction; In order to solve the above-mentioned technical problem, the following configuration is used. It is characterized by being prepared.

[0011] That is, the magnetically sensitive portion is provided with at least one wire in order to change the potential difference between the pair of output terminals, which is caused only by the current flowing between the pair of input terminals.
A plurality of parallel conductive paths are provided that are scheduled for one disconnection.

[0012] In a more specific first aspect of the invention,
The magnetically sensitive portion is made of a cross-shaped thin film in which the pair of first ends and the pair of second ends are located at the ends of the four protrusions, respectively, and the conductive path is , provided by a plurality of bypasses shorting at least two adjacent protrusions of the cross.

[0013] In a more specific second aspect of the invention,
The conductive path is provided by a plurality of taps connecting at least one of the pair of second ends and different positions in the middle of the pair of first ends.

[0014]

[Operation] In the present invention, the symmetry of the magnetically sensitive portion is changed by cutting a specific one of the plurality of conductive paths provided by the plurality of bypasses, taps, etc. Therefore, it is possible to change the potential difference between the pair of output terminals, that is, the unbalanced voltage, which is caused only by the current flowing between the pair of input terminals. Therefore, by selecting the number or types of conductive paths to be cut from among the plurality of conductive paths, the value of the unbalanced voltage can be adjusted to be minimized.

[0015]

Therefore, according to the present invention, since the value of unbalanced voltage can be reduced, the burden on the signal processing circuit can be reduced, and therefore the cost of the signal processing circuit itself can be reduced and the size can be reduced. It is possible to aim for

Furthermore, since no current flows through the conductive path that is cut in order to reduce the unbalanced voltage value, even if impurities such as combustion products generated by a laser or the like remain during cutting, Performance such as temperature characteristics of the Hall element is not affected.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a Hall element 11 according to an embodiment of the present invention.

Similar to the conventional Hall element 1 shown in FIG. 3, this Hall element 11 includes a magnetically sensitive portion 12 made of a cross-shaped thin film. In addition, the four protrusions 13 of the magnetically sensitive portion 12
, 14, 15, and 16, a pair of input terminals 17 and 18 are connected to the ends of the protrusions 13 and 14 that face each other in the first direction, respectively. On the other hand, a pair of output terminals 19 and 20 are connected to the ends of the protrusions 15 and 16 facing in a second direction that intersects (more specifically, perpendicularly intersects) the above-mentioned first direction. be done.

A current is applied to the magnetically sensitive portion 12 from a power source 21 via a pair of input terminals 17 and 18 . At this time, even in the absence of a magnetic field, a potential difference, that is, an unbalanced voltage, may occur between the pair of output terminals 19 and 20 due to the above-described current alone. In order to change (reduce) this unbalanced voltage, the magnetically sensitive portion 12 is provided with a plurality of bypasses 22, 23, 24, 25, respectively, so as to short-circuit between adjacent protrusions 13-16. There is. In this embodiment, these bypasses 22 to 25 are
It is composed of a strip-shaped thin film made of the same material as the material constituting the magnetically sensitive portion 12.

Adjustments to minimize unbalanced voltages are made as follows. That is, the power supply 21 is connected to the pair of input terminals 17 and 18, and the pair of output terminals 19 and 2 is thereby connected to the pair of output terminals 19 and 2 while current is flowing through the magnetically sensitive portion 12.
Measure the value of the unbalanced voltage through 0. According to this measurement value, it is determined which of the bypasses 22 to 25 should be cut, and according to the determination, the cut is performed using, for example, a laser, and then the unbalanced voltage is measured again. If this value is not within the standard value,
By advancing the cutting of specific bypasses 22 to 25 inward and repeating such operations, the unbalanced voltage V
The value of H is brought to a minimum value in an adjustable range.

[0021] Although bypasses 22 to 25 are formed between all of the adjacent protrusions 13 to 16 in the magnetically sensitive portion 12 shown in FIG. , it may be only between two adjacent protrusions 13 to 16.

Furthermore, the conductive paths such as the bypasses 22 to 25 may be made of a material other than the material forming the magnetically sensitive portion 12.

FIG. 2 shows a Hall element 11a according to another embodiment of the invention. In addition, in FIG. 2,
Elements corresponding to the elements shown in FIG. 1 described above are given the same reference numerals, and overlapping explanations will be omitted.

The Hall element 11a shown in FIG. 2 has a feature in the protrusion 15 of the magnetically sensitive portion 12. That is, a plurality of taps 26 are formed on this protrusion 15 . Each tap 26 connects one output terminal 19 to a different position in the middle of a conductive path formed between a pair of input terminals 17 and 18 in parallel.

In such a Hall element 11a, adjustment to minimize the value of unbalanced voltage is performed as follows. That is, a power supply 21 is connected to a pair of input terminals 17 and 18, and while a current is flowing between the pair of input terminals 17 and 18, an unbalanced voltage is applied through a pair of output terminals 19 and 20. The value is measured. and,
Depending on this measured value, it is determined which of the taps 23 to 26 should be cut, and the cutting is performed according to this determination.

Note that in the Hall element 11a shown in FIG. 2, a tap 26 is formed on one output terminal 19 side.
A similar tap may also be formed on the other output terminal 20 side.

Furthermore, the magnetically sensitive portion 1 in which the tap 26 is formed
2 has a cross shape as a whole in FIG. 2, but it is not limited to such a cross shape, but may have other shapes.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing a Hall element 11 according to an embodiment of the present invention.

FIG. 2: Hall element 11a according to another embodiment of the invention.
FIG.

FIG. 3 is a schematic plan view showing a typical conventional Hall element 1.

FIG. 4 is a diagram showing the relationship between the Hall voltage VH and the magnetic flux density B realized in a general Hall element, and particularly shows the shift state of the Hall voltage VH due to the generation of the unbalanced voltage VHO.

[Explanation of symbols]

11, 11a Hall element 12 Magnetically sensitive part 13, 14, 15, 16 Projection part 17, 18 Input terminal 19,20 Output terminal 22, 23, 24, 25 Bypass 26 Tap

Claims (3)

[Claims] 1. A magnetically sensitive portion, a pair of input terminals respectively connected to a pair of first ends facing in a first direction of the magnetically sensitive portion, and In a Hall element including a pair of output terminals respectively connected to a pair of second ends facing in a second direction intersecting with characterized in that a plurality of parallel conductive paths are provided, at least one of which is intended for disconnection, in order to modify the potential difference between the pair of output terminals caused solely by a current flowing between them, Hall element. 2. The magnetically sensitive portion is made of a cross-shaped thin film in which the pair of first ends and the pair of second ends are located at the ends of four protrusions, respectively. , the conductive path is provided by a plurality of bypasses that short-circuit at least two adjacent protrusions of the cross shape,
The Hall element according to claim 1. 3. The conductive path is provided by a plurality of taps connecting at least one of the pair of second ends and different positions in the middle of the pair of first ends. 1. The Hall element according to 1.