JP2667283B2 - Magnetoresistive magnetic sensor - Google Patents
Magnetoresistive magnetic sensorInfo
- Publication number
- JP2667283B2 JP2667283B2 JP2199123A JP19912390A JP2667283B2 JP 2667283 B2 JP2667283 B2 JP 2667283B2 JP 2199123 A JP2199123 A JP 2199123A JP 19912390 A JP19912390 A JP 19912390A JP 2667283 B2 JP2667283 B2 JP 2667283B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetoresistive
- temperature
- magnetic sensor
- output
- effect
- 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.)
- Expired - Fee Related
Links
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- Measuring Magnetic Variables (AREA)
- Hall/Mr Elements (AREA)
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。Description: TECHNICAL FIELD The present invention relates to a magnetoresistance effect type 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 a conventional magnetoresistive magnetic sensor, for example,
The ones shown in JP-B-57-5067 and JP-B-54-41335 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
応じて減少する。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 magnetoresistance ratio decreases with increasing temperature. Therefore, the conventional magnetoresistance effect type magnetic sensor cannot obtain an effective output in a temperature range exceeding, for example, 70 ° C., and cannot maintain its 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。In view of the above, an object of the present invention is to provide a magnetoresistive sensor capable of compensating for a decrease in the magnetoresistive effect due to a temperature rise and obtaining an 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
なり、且つ各磁気抵抗効果素子における磁気抵抗効果の
温度による減少率と固有抵抗の温度による上昇率とをほ
ぼ等しいものとした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 having one end grounded and the other end connected to a constant current circuit are provided in parallel, and the potential difference between the pair of magnetoresistive elements is output. This is achieved by a magnetoresistive effect type magnetic sensor in which the rate of decrease of the magnetoresistive effect in a magnetoresistive element due to temperature is substantially equal to the rate of increase in the specific resistance due to temperature.
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 effect type magnetic sensor, the magnetoresistive effect rate of the magnetoresistive effect element decreases with an increase in temperature, but at the same time, the specific resistance of the magnetoresistive effect element increases with an increase in temperature,
In addition, it is based on the knowledge of the fact that the decrease and the increase have a numerically substantially corresponding 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 is caused to flow through the magnetoresistive element by the constant current circuit, and a voltage correlated with the constant current is output, so that the offset between the decrease and the increase in the above-described correspondence is used. As a result, an output that is not affected by temperature changes can be obtained.
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。Hereinafter, an embodiment of the magnetoresistive magnetic sensor according to the present invention will be described.
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。This magnetoresistive sensor 1 has a pair of magnetoresistive elements 2a and 2b provided in parallel as shown in the figure, one end of which is grounded, and a constant current circuit 3 connected to the other end. The output ΔV is obtained by the potential difference between the magnetoresistive elements 2a and 2b. Here, the pair of magnetoresistive elements 2a and 2b preferably have the same characteristics as each other, but are not necessarily indispensable.
このように定電流回路３を接続した磁気抵抗効果素子
2a、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 having the constant current circuit 3 connected as described above.
By using 2a and 2b and obtaining the output ΔV by the potential difference between them, it is possible to compensate for the decrease in the magnetoresistance effect due to the rise in temperature, which is higher than the temperature atmosphere in which the conventional one can be used effectively. Effective output can be obtained even in a high temperature atmosphere.
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。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Ｋρについてデータを取ってみたところ、Ks＝−
0.223％／℃でありＫρ＝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。As described above, the magnetoresistance effect ratio S of the magnetoresistance effect element
Has been found to decrease with increasing temperature, while the resistivity ρ of the magnetoresistive element has increased with increasing temperature. When data was obtained for the decrease rate Ks of the magnetoresistance effect rate S and the increase rate Kρ of the specific resistance ρ, Ks = −
0.223% / ° C. and Kρ = 0.221% / ° C. The discovery of this fact has led to the temperature compensation for the magnetoresistance effect rate by the above-described 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 described in detail below.
磁気抵抗効果素子に磁界Ｈがかかっているときに定電
流ｉを流すとその両端の電圧Ｖは、 Ｖ＝ｉ・ρ（ｔ）〔１＋Ｓ（ｔ）〕 となる。When a constant current i is applied while a magnetic field H is applied to the magnetoresistive effect element, the voltage V between both ends becomes V = i · ρ (t) [1 + S (t)].
ここで、ある温度ｔにおける磁気抵抗効果素子の固有
抵抗ρ（ｔ）は、 ρ（ｔ）＝ρ（１＋Ｋρ・ｔ） また、ある温度ｔにおける磁気抵抗変化率Ｓ（ｔ）は、 Ｓ（ｔ）＝Ｓ（１＋Ks・ｔ） となる。Here, the specific resistance ρ (t) of the magnetoresistive element at a certain temperature t is ρ (t) = ρ (1 + Kρ · t), and the magnetoresistance change rate S (t) at a certain temperature t is S ( t) = the S (1 + K s · t ).
よって、ある温度ｔにおける磁気抵抗効果素子の電気
抵抗Ｒ（ｔ）は、 Ｒ（ｔ）＝ρ（ｔ）〔１＋Ｓ（ｔ）〕 となり、磁気抵抗効果による抵抗の変化分ΔＲ（ｔ）
は、 ΔＲ（ｔ）＝ρ（１＋Ｋρ・ｔ）・Ｓ（１＋Ks・ｔ） となる。この式を展開すると、 ΔＲ（ｔ）＝ρ・Ｓ（１＋Ks・ｔ＋Ｋρ・ｔ＋ＫρKs・
t2） となり、Ｋρ・Ks・t2は二乗項であり無視し得るから結
局、 ΔＲ（ｔ）＝ρ・Ｓ（１＋Ks・ｔ＋Ｋρ・ｔ） となる。Therefore, the electric resistance R (t) of the magnetoresistive element at a certain temperature t is R (t) = ρ (t) [1 + S (t)], and the resistance change ΔR (t) due to the magnetoresistive effect is obtained.
Is a ΔR (t) = ρ (1 + K ρ · t) · S (1 + K s · t). Expanding this expression, ΔR (t) = ρ · S (1 + K s · t + K ρ · t + K ρ K s ·
t 2 ), and K ρ · K s · t 2 is a square term and can be ignored, and eventually ΔR (t) = ρ · S (1 + K s · t + K ρ · t).
ここで、前述のようにKs≒−Ｋρであれば、 ΔＲ（ｔ）＝ρ・Ｓ となり、ΔＲ（ｔ）すなわち磁気抵抗効果による抵抗の
変化分は温度の影響を受けないことが分かる。Here, if K s ≒ −K ρ as described above, ΔR (t) = ρ · S, and it can be seen that ΔR (t), that is, the change in resistance due to the magnetoresistance effect is not affected by temperature. .
一方、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−Vb となる。ここで、 Va＝ｉ・Ra ＝ｉ・ρ0a（１＋Ｋρ ａ・ｔ）＋ｉ・ΔRa ＝ｉ・ρ0a（１＋Ｋρ ａ・ｔ）＋ｉ・ρ0a・Sa Vb＝ｉ・Rb ＝ｉ・ρ0b（１＋Ｋρ ｂ・ｔ）＋ｉ・ΔRb ＝ｉ・ρ0b（１＋Ｋρ ｂ・ｔ）＋ｉ・ρ0b・Sb と表される。On the other hand, the output ΔV is the difference between the voltage changes that occur in the magnetoresistive elements 2a and 2b that are affected by magnets having different strengths, and ΔV = Va−Vb. Here, Va = i · R a = i · ρ 0a (1 + K ρ a · t) + i · ΔR a = i · ρ 0a (1 + K ρ a · t) + i · ρ 0a · S a Vb = i · R b = I · ρ 0b (1 + K ρ b · t) + i · ΔR b = i · ρ 0b (1 + K ρ b · t) + i · ρ 0b · S b
磁気抵抗効果素子2a、2bが同一の特性を持つとする
と、ρ0a≒ρ0b≒ρ０とおくことができるから、 ΔＶ＝ｉ・ρ０（Ｋρ ａ−Ｋρ ｂ）ｔ＋ｉ・ρ０・（Sa
−Sb） 磁気抵抗効果素子2a、2bが同一の素材であればＫρ ａ
＝Ｋρ ｂと見なせるから、 ΔＶ＝ｉ・ρ０（Sa−Sb）＝ｉ・Δρ となり、温度の影響を受けないことになる。Assuming that the magnetoresistive elements 2a and 2b have the same characteristics, ρ 0a ≒ ρ 0b ≒ ρ 0 , so that ΔV = i · ρ 0 (K ρ a −K ρ b ) t + i · ρ 0・ (S a
−S b ) If the magnetoresistive elements 2a and 2b are of the same material, K ρ a
Since = regarded as K [rho b, it will not undergo ΔV = i · ρ 0 (S a -S b) = i · Δρ next, the effects of temperature.
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 with the output in the above-mentioned Japanese Patent Publication No. 57-5067.
すなわち、特公昭57−5067号では、 として出力ΔＶを得ている。That is, in Japanese Patent Publication No. 57-5067, Is obtained as the output ΔV.
ここで、この式中の“Δρ”が前述の本発明における
Δρ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、分母の磁界を加えない場合
の抵抗つまり固有抵抗ρ０が温度ｔにおいてρ０（ｔ）
＝ρ０（１＋Ｋρｔ）と増大し、この結果、出力ΔＶ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 equation corresponds to Δρ in the present invention described above, and “Δρ” is not affected by temperature for the same reason as described above, but is the resistance when no denominator magnetic field is applied. That is, the specific resistance ρ 0 becomes ρ 0 (t) at the temperature t.
= Ρ 0 (1 + K ρ t), and as a result, the output ΔV decreases, 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 effect type magnetic sensor according to the present invention, a constant current is applied to the magnetoresistive element, and a voltage correlated with the constant current is output, so that a decrease in the magnetoresistive effect due to a temperature rise is compensated. Effective sensitivity can be maintained 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……磁気抵抗効果型磁気センサ 2a、2b……磁気抵抗効果素子 ３……定電流回路 The figure is a circuit diagram of the magnetoresistive magnetic sensor. 1 ... Magnetoresistance effect type magnetic sensor 2a, 2b ... Magnetoresistance effect element 3 ... Constant current circuit
Claims (1)
磁気センサに於いて、 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てなっており、且つ各磁
気抵抗効果素子の磁気抵抗効果の温度による減少率と固
有抵抗の温度による上昇率とがほぼ等しいことを特徴と
する磁気抵抗効果型磁気センサ。In a magnetoresistive magnetic sensor using a magnetoresistive element, a pair of magnetoresistive elements having one end grounded and the other end connected to a constant current circuit are provided in parallel, and the pair of magnetic sensors is provided. A magnetoresistive element characterized in that a potential difference between the resistance effect elements is output, and a decrease rate of the magnetoresistance effect of each of the magnetoresistance effect elements by temperature is substantially equal to a rise rate of the specific resistance by temperature. Effect type magnetic sensor.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2199123A JP2667283B2 (en) | 1990-07-30 | 1990-07-30 | Magnetoresistive magnetic sensor |
| PCT/JP1991/001017 WO1992002826A1 (en) | 1990-07-30 | 1991-07-30 | Magnetoresistance-effect magnetic sensor |
| KR1019930700263A KR930702686A (en) | 1990-07-30 | 1991-07-30 | Magnetoresistive type magnetic sensor |
| EP91913127A EP0541806B1 (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 |
| 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 JPH0486577A (en) | 1992-03-19 |
| JP2667283B2 true 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) |
Families Citing this family (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 |
| DE19654273A1 (en) * | 1995-12-26 | 1997-07-03 | Aisin Seiki | Steering wheel position adjuster for vehicle with manual steering |
| JPH11195211A (en) | 1997-12-26 | 1999-07-21 | Fujitsu Ltd | Magnetic reproducing device |
Family Cites Families (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
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0486577A (en) | 1992-03-19 |
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