JPH0486577A - Magnetoresistance effect type magnetic sensor - Google Patents
Magnetoresistance effect type magnetic sensorInfo
- Publication number
- JPH0486577A JPH0486577A JP2199123A JP19912390A JPH0486577A JP H0486577 A JPH0486577 A JP H0486577A JP 2199123 A JP2199123 A JP 2199123A JP 19912390 A JP19912390 A JP 19912390A JP H0486577 A JPH0486577 A JP H0486577A
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- magnetoresistive
- output
- elements
- constant current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000000694 effects Effects 0.000 title abstract description 16
- 230000007423 decrease Effects 0.000 abstract description 13
- 230000035945 sensitivity Effects 0.000 abstract description 2
- 230000002596 correlated effect Effects 0.000 description 2
- 230000000875 corresponding effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005389 magnetism Effects 0.000 description 1
Landscapes
- Measuring Magnetic Variables (AREA)
- Hall/Mr Elements (AREA)
Abstract
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は磁気抵抗効果型磁気センサに関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a magnetoresistive magnetic sensor.
従来の磁気抵抗効果型磁気センサとしては、例えば、特
公昭５７−５０６７号、特公昭５４−４１３３５号等に
示されるようなものが知られている。As conventional magnetoresistive magnetic sensors, those shown in Japanese Patent Publication No. 57-5067, Japanese Patent Publication No. 41335-1987, etc. are known.
よく知れているように磁気抵抗効果率は温度の上昇に応
して減少する。そのため、従来の磁気抵抗効果型磁気セ
ンサは、例えば７０℃を超える温度範囲においては有効
な出力が得られず、信頼性を保ち得なかった。As is well known, the magnetoresistive effect rate decreases as the temperature increases. Therefore, conventional magnetoresistive magnetic sensors cannot provide effective output in a temperature range exceeding 70° C., and cannot maintain reliability.
そこで、この発明では温度上昇による磁気抵抗効果率の
減少分が補償され、高温度雰囲気でも有効な出力が得ら
れる磁気抵抗効果型磁気センサを提供しようとするもの
である。Therefore, it is an object of the present invention to provide a magnetoresistive magnetic sensor that compensates for the decrease in magnetoresistive efficiency due to temperature rise and that can provide effective output even in a high-temperature atmosphere.
このような目的は、一端を接地し他端に定電流回路を接
続した磁気抵抗効果素子を一対、並列に設け、この一対
の磁気抵抗効果素子間の電位差を出力するようにしてな
る磁気抵抗効果型磁気センサにより達成される。For this purpose, a pair of magnetoresistive elements, one end of which is grounded and the other end connected to a constant current circuit, are installed in parallel, and the potential difference between the pair of magnetoresistive elements is output. This is achieved by a type magnetic sensor.
この磁気抵抗効果型磁気センサは、磁気抵抗効果素子の
磁気抵抗効果率が温度上昇により減少するが、同時に磁
気抵抗効果素子の固有抵抗が温度上昇により増大し、し
かもこの減少分と増加分とが数値的に略対応関係にある
という事実についての知見に基づくものである。In this magnetoresistive magnetic sensor, the magnetoresistive effect rate of the magnetoresistive element decreases as the temperature rises, but at the same time, the specific resistance of the magnetoresistive element increases as the temperature rises, and this decrease and increase are This is based on the knowledge that there is a numerical correspondence relationship.
すなわち、定電流回路により一定の電流を磁気抵抗効果
素子に流し、この定電流に相関する電圧を出力とするよ
うにしているので、前記の対応関係にある減少分と増加
分との相殺を利用することができ、結果として温度変化
に左右されない出力を得られるようになる。In other words, a constant current circuit causes a constant current to flow through the magnetoresistive element, and a voltage correlated to this constant current is output, so the offset between the decrease and increase in the correspondence relationship described above is used. As a result, it becomes possible to obtain output that is not affected by temperature changes.
以下、この発明による磁気抵抗効果型磁気センサの一実
施例を説明する。An embodiment of the magnetoresistive magnetic sensor according to the present invention will be described below.
この磁気抵抗効果型磁気センサ１は、図に示すように一
対の磁気抵抗効果素子２ａ、２ｂを並列に設け、各々の
一端を接地すると共に、各々の他端に定電流回路３を接
続してなるもので、磁気抵抗効果素子２ａ、２ｂの間の
電位差により出力ΔＶを得るようにしている。ここで、
一対の磁気抵抗効果素子２ａ、２ｂは、互いに同一の特
性を持っていることが好ましいが、必ずしも不可欠では
ない。As shown in the figure, this magnetoresistive magnetic sensor 1 has a pair of magnetoresistive elements 2a and 2b arranged in parallel, one end of each is grounded, and a constant current circuit 3 is connected to the other end of each. The output ΔV is obtained by the potential difference between the magnetoresistive elements 2a and 2b. here,
It is preferable that the pair of magnetoresistive elements 2a and 2b have the same characteristics, but this is not necessarily essential.
このように定電流回路３を接続した磁気抵抗効果素子２
ａ、２ｂを用い、その間の電位差で出力ΔＶを得るもの
とすることにより、磁気抵抗効果率の温度の上昇による
減少を補償し得て、従来のものが有効使用可能であった
温度雰囲気より高い高温度雰囲気でも有効な出力を得ら
れるようになる。The magnetoresistive element 2 connected to the constant current circuit 3 in this way
By using a and 2b and obtaining the output ΔV by the potential difference between them, it is possible to compensate for the decrease in the magnetoresistive effect rate due to an increase in temperature, and it is possible to compensate for the decrease in the magnetoresistive effect rate due to an increase in temperature, and the temperature is higher than that in which the conventional one can be used effectively. Effective output can be obtained even in high temperature environments.
その理由は以下の通りである。The reason is as follows.
前述のように、磁気抵抗効果素子の磁気抵抗効果率Ｓは
温度上昇により減少し、他方、磁気抵抗効果素子の固有
抵抗ρは温度上昇により増加することが分かっている。As mentioned above, it is known that the magnetoresistive effect ratio S of the magnetoresistive element decreases as the temperature rises, while the specific resistance ρ of the magnetoresistive element increases as the temperature rises.
この磁気抵抗効果率Ｓの減少率Ｋｓ及び固有抵抗ρの増
加率にρについてデータを取ってみたところ、Ｋｓ＝−
０，２２３％／℃でありにρ＝０．２２１％／℃である
ことが分かった。そして、この事実の発見こそが、前述
のような構成による磁気抵抗効果率についての温度補償
を導いたものである。When I collected data on the rate of decrease Ks of the magnetoresistive effect S and the rate of increase of the specific resistance ρ, I found that Ks=-
It was found that ρ=0.223%/°C and ρ=0.221%/°C. The discovery of this fact led to the temperature compensation of the magnetoresistive effect rate using the above-mentioned configuration.
このことを具体的に説明すると以下の通りである。This will be explained specifically as follows.
出力ΔＶは、それぞれ異なる強さの磁気の影響を受ける
磁気抵抗効果素子２ａ、２ｂにおいてそれぞれ生じる電
圧変化の差であり、
ΔＶ＝（Ｖａ＋ΔＶａ）−（Ｖｂ＋ΔＶｂ）となる。こ
こで、磁気抵抗効果素子２ａ、２ｂが同一の特性を持つ
とすると、
ΔＶ＝ΔＶａ−Δｖｂ
となり、磁気抵抗効果素子２ａ、２ｂそれぞれの磁気抵
抗効果による抵抗変化をΔρａ、Δρｂとすると、ΔＶ
ａ＝Δρａ−１であり、Δｖｂ＝Δρｂ−１であるから
、
ΔＶ＝（Δρａ−Δρｂ）拳ｉ
となる。（ｉは定電流回路３により与えられる所定の電
流値。）
この式において磁気抵抗効果による抵抗の変化分である
（Δρａ−Δρｂ） ＝Δρ＝ρ・Ｓが温度によりどの
ような影響を受けるかを以下にみる。The output ΔV is the difference between the voltage changes occurring in the magnetoresistive elements 2a and 2b that are affected by magnetism of different strengths, and is expressed as ΔV=(Va+ΔVa)−(Vb+ΔVb). Here, if the magnetoresistive elements 2a and 2b have the same characteristics, ΔV = ΔVa - Δvb, and if the resistance changes due to the magnetoresistive effect of the magnetoresistive elements 2a and 2b are Δρa and Δρb, then ΔV
Since a=Δρa−1 and Δvb=Δρb−1, ΔV=(Δρa−Δρb)fist i. (i is the predetermined current value given by the constant current circuit 3.) In this equation, how is the change in resistance due to the magnetoresistive effect (Δρa - Δρb) = Δρ=ρ・S affected by temperature? See below.
ある温度ｔにおける磁気抵抗効果素子の固有抵抗ρ（１
）は、
ρ（ｔ）＝ρ（１＋にρｔ）
また、ある温度ｔにおける磁気抵抗変化率５（１）は、
Ｓ （ｔ）＝Ｓ （１＋Ｋｓ ｔ）
となる。The specific resistance ρ(1
) is ρ(t)=ρ(ρt to 1+) Furthermore, the rate of change in magnetoresistance 5(1) at a certain temperature t is S(t)=S(1+Ks t).
したがって、ある温度ｔにおける磁気抵抗効果による抵
抗の変化分Δρ（１）は、
Δρ（ｔ）＝ρ（１＋にρｔ）・Ｓ （１＋Ｋｓｔ）
となる。この式を展開すると、
ΔＤ （ｔ）＝Ｄ −Ｓ （１＋Ｋｓ ｔ＋にρｔ＋に
ρＫｓ ｔ２）
となり、ＫρＫｓ ｔ２は二乗項であり無視し得るから
結局、
Δｏ （Ｄ ＝ｏ −Ｓ （１＋ＫＳ ｔ＋にρｔ）と
なる。Therefore, the change in resistance Δρ(1) due to the magnetoresistive effect at a certain temperature t is as follows: Δρ(t)=ρ(ρt to 1+)·S (1+Kst). Expanding this equation, ΔD (t) = D - S (1+Ks t+ to ρt+ to ρKs t2), and KρKs t2 is a square term and can be ignored, so in the end, Δo (D = o -S (1+KS t+ to ρt ).
ここで、前述のようにＫｓ＝−にρであるから結局、
Δρ （ｔ） ＝ρ 拳 Ｓ
となり、Δρは温度の影響を受けないことが分かる。こ
のようにΔρが温度の影響をうけなければΔＶ＝Δρ・
ｉも当然に温度に左右されないことになる。Here, since ρ is Ks=− as described above, Δρ (t) = ρ fist S after all, and it can be seen that Δρ is not affected by temperature. If Δρ is not affected by temperature in this way, ΔV=Δρ・
Naturally, i is not affected by temperature either.
このことの意味は、前述の特公昭５７−５０６７号にお
ける出力と比較することでより明確になる。The meaning of this becomes clearer by comparing it with the output in Japanese Patent Publication No. 57-5067 mentioned above.
すなわち、特公昭５７−５０６７号では、として出力Δ
Ｖを得ている。That is, in Japanese Patent Publication No. 57-5067, the output Δ is
I'm getting V.
ここで、この式中の“Δρ”が前述の本発明におけるΔ
ρと対応し、“Δρ”は前述したのと同様の理由により
温度の影響をうけないが、磁界を加えない場合の抵抗つ
まり固有抵抗ρ。が温度ｔにおいてρ。（ｔ）＝ρ。（
１＋にρｔ）と増大し、この結果、出力△Ｖが小さくな
ってしまい、本発明におけるような温度補償効果が得ら
れないものである。Here, “Δρ” in this formula is Δρ in the above-mentioned present invention.
Corresponding to ρ, “Δρ” is not affected by temperature for the same reason as mentioned above, but is the resistance when no magnetic field is applied, that is, the specific resistance ρ. is ρ at temperature t. (t)=ρ. (
As a result, the output ΔV becomes small, and the temperature compensation effect as in the present invention cannot be obtained.
この発明による磁気抵抗効果型磁気センサは、磁気抵抗
効果素子に定電流を流し、この定電流に相関する電圧を
出力とするようにしているので、温度上昇による磁気抵
抗効果の減少分が補償され、従来に比べより高い温度範
囲においても有効な感度を保ち得る。In the magnetoresistive magnetic sensor according to the present invention, a constant current is passed through the magnetoresistive element and a voltage correlated to this constant current is outputted, so that the decrease in the magnetoresistive effect due to temperature rise is compensated for. , it is possible to maintain effective sensitivity even in a higher temperature range than before.
図は磁気抵抗効果型磁気センサの回路図である。 １−ミー磁気抵抗効果型磁気センサ ２ａ、２ｂ−・−磁気抵抗効果素子 ３゛一定電流回路 The figure is a circuit diagram of a magnetoresistive magnetic sensor. 1-Me magnetoresistive magnetic sensor 2a, 2b--Magnetoresistive element 3゛Constant current circuit
Claims (1)
於いて、 一端を接地し他端に定電流回路を接続した磁気抵抗効果
素子を一対、並列に設け、この一対の磁気抵抗効果素子
間の電位差を出力するようにしたことを特徴とする磁気
抵抗効果型磁気センサ。[Claims] In a magnetoresistive magnetic sensor using magnetoresistive elements, a pair of magnetoresistive elements each having one end grounded and the other end connected to a constant current circuit are provided in parallel, and the pair of magnetoresistive elements are connected in parallel. A magnetoresistive magnetic sensor characterized by outputting a potential difference between magnetoresistive elements.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2199123A JP2667283B2 (en) | 1990-07-30 | 1990-07-30 | Magnetoresistive magnetic sensor |
| KR1019930700263A KR930702686A (en) | 1990-07-30 | 1991-07-30 | Magnetoresistive type magnetic sensor |
| PCT/JP1991/001017 WO1992002826A1 (en) | 1990-07-30 | 1991-07-30 | Magnetoresistance-effect magnetic sensor |
| DE69125612T DE69125612T2 (en) | 1990-07-30 | 1991-07-30 | MAGNETIC PROBE WITH MAGNETIC RESISTANCE EFFECT |
| EP91913127A EP0541806B1 (en) | 1990-07-30 | 1991-07-30 | Magnetoresistance-effect magnetic sensor |
| US08/264,211 US5589768A (en) | 1990-07-30 | 1994-06-23 | Magnetoresistance-effect magnetic sensor of the temperature compensating type |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2199123A JP2667283B2 (en) | 1990-07-30 | 1990-07-30 | Magnetoresistive magnetic sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0486577A true JPH0486577A (en) | 1992-03-19 |
| JP2667283B2 JP2667283B2 (en) | 1997-10-27 |
Family
ID=16402523
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2199123A Expired - Fee Related JP2667283B2 (en) | 1990-07-30 | 1990-07-30 | Magnetoresistive magnetic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2667283B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5297881A (en) * | 1991-05-16 | 1994-03-29 | Mitsubishi Steel Mfg. Co., Ltd. | Printing machine carriage having a magnetic encoder |
| US5806890A (en) * | 1995-12-26 | 1998-09-15 | Aisin Seiki Kabushiki Kaisha | Steering wheel position adjusting apparatus for a vehicular steering system |
| US6262858B1 (en) | 1997-12-26 | 2001-07-17 | Fujitsu Limited | Magnetic disk device for controlling a sense current supplied to a magneto-resistive head based on an ambient temperature |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5337204A (en) * | 1976-06-11 | 1978-04-06 | Babcock & Wilcox Ltd | Boiler for use in ship |
| JPS59111011A (en) * | 1982-12-17 | 1984-06-27 | Copal Co Ltd | Magnetic detector with magneto-resistance element |
-
1990
- 1990-07-30 JP JP2199123A patent/JP2667283B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5337204A (en) * | 1976-06-11 | 1978-04-06 | Babcock & Wilcox Ltd | Boiler for use in ship |
| JPS59111011A (en) * | 1982-12-17 | 1984-06-27 | Copal Co Ltd | Magnetic detector with magneto-resistance element |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5297881A (en) * | 1991-05-16 | 1994-03-29 | Mitsubishi Steel Mfg. Co., Ltd. | Printing machine carriage having a magnetic encoder |
| US5806890A (en) * | 1995-12-26 | 1998-09-15 | Aisin Seiki Kabushiki Kaisha | Steering wheel position adjusting apparatus for a vehicular steering system |
| US6262858B1 (en) | 1997-12-26 | 2001-07-17 | Fujitsu Limited | Magnetic disk device for controlling a sense current supplied to a magneto-resistive head based on an ambient temperature |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2667283B2 (en) | 1997-10-27 |
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