JPH086260Y2 - Magnetoresistive element circuit - Google Patents
Magnetoresistive element circuitInfo
- Publication number
- JPH086260Y2 JPH086260Y2 JP1990003166U JP316690U JPH086260Y2 JP H086260 Y2 JPH086260 Y2 JP H086260Y2 JP 1990003166 U JP1990003166 U JP 1990003166U JP 316690 U JP316690 U JP 316690U JP H086260 Y2 JPH086260 Y2 JP H086260Y2
- Authority
- JP
- Japan
- Prior art keywords
- magnetoresistive effect
- effect element
- circuit
- current mirror
- mirror circuit
- 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 - Lifetime
Links
- 230000000694 effects Effects 0.000 claims description 48
- 230000003252 repetitive effect Effects 0.000 claims description 7
- 230000007423 decrease Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 4
- 239000010409 thin film Substances 0.000 description 2
- 229910017709 Ni Co Inorganic materials 0.000 description 1
- 229910003267 Ni-Co Inorganic materials 0.000 description 1
- 229910003271 Ni-Fe Inorganic materials 0.000 description 1
- 229910003262 Ni‐Co Inorganic materials 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
Landscapes
- Transmission And Conversion Of Sensor Element Output (AREA)
Description
【考案の詳細な説明】 〔産業上の利用分野〕 本考案は、磁気抵抗効果素子を用い繰り返し磁気信号
との位置関係による抵抗値の変動を利用して、例えば回
転角度や移動位置の検出等を可能にした磁気抵抗効果素
子回路に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention utilizes a magnetoresistive effect element to detect fluctuations in resistance value due to positional relationship with repeated magnetic signals, for example, detection of a rotation angle or a moving position. The present invention relates to a magnetoresistive effect element circuit that enables the above.
Ni−Fe、Ni−Co等の金属薄膜は、これを帯状に形成す
るとその薄膜の面内でかつ長手方向と直交する方向に磁
界が加わったときにその抵抗値が低下する現象をもって
いる。そこでこのような磁気抵抗効果素子と繰り返し磁
気信号の位置関係に応じて信号を取り出すようにした磁
気抵抗効果素子回路が従来から提案されている。When a metal thin film of Ni-Fe, Ni-Co or the like is formed into a strip shape, its resistance value decreases when a magnetic field is applied in the plane of the thin film and in the direction orthogonal to the longitudinal direction. Therefore, conventionally, a magnetoresistive effect element circuit has been proposed in which a signal is taken out according to the positional relationship between such a magnetoresistive effect element and a magnetic signal repeatedly.
第２図は、特公昭54−413335号公報で開示されている
このような磁気抵抗効果素子回路の動作原理を表わした
ものである。この図で２つの磁気抵抗効果素子11、12は
波長λの繰り返し磁気パターン13に対してその間隔ｄが
ほぼ次の式の関係を満足するように長手方向を平行にし
て配置されている。FIG. 2 shows the operating principle of such a magnetoresistive effect element circuit disclosed in Japanese Patent Publication No. 54-413335. In this figure, the two magnetoresistive effect elements 11 and 12 are arranged with their longitudinal directions parallel to each other with respect to the repetitive magnetic pattern 13 having the wavelength λ so that the distance d substantially satisfies the following equation.
ただし、ｎは０あるいは正の整数である。 However, n is 0 or a positive integer.
第１の磁気抵抗効果素子11の一端は第１の端子14に接
続され、他端は第２の磁気抵抗効果素子12の一端に接続
されると共に第２の端子15に接続されている。第２の磁
気抵抗効果素子12の他端は、第３の端子16に接続されて
いる。第１および第３の端子14、16は電流供給端子とし
ての役割を果たすもので、これらの間には電圧Ｖの電源
17が接続されている。One end of the first magnetoresistive effect element 11 is connected to the first terminal 14, and the other end is connected to one end of the second magnetoresistive effect element 12 and also to the second terminal 15. The other end of the second magnetoresistive effect element 12 is connected to the third terminal 16. The first and third terminals 14 and 16 serve as current supply terminals, and a power supply of voltage V is placed between them.
17 connected.
この回路で、第１と第２の端子14、15の間から出力電
圧V0を取り出すものとする。２つの磁気抵抗効果素子1
1、12に磁界が加わっていない状態でこれらの抵抗値を
Ｒとする。繰り返し磁気パターン13が図示の位置関係の
とき第１の磁気抵抗効果素子11の抵抗値はＲのままであ
り、第２の磁気抵抗効果素子12の抵抗値はΔＲだけ減少
してＲ−ΔＲとなっている。この状態では、出力電圧V0
は電圧Ｖを1/2にした値よりも大きい極大の状態とな
る。In this circuit, the output voltage V 0 is taken out from between the first and second terminals 14 and 15. Two magnetoresistive effect elements 1
Let R be the resistance value of 1 and 12 when no magnetic field is applied. When the repeated magnetic pattern 13 has the positional relationship shown in the drawing, the resistance value of the first magnetoresistive effect element 11 remains R, and the resistance value of the second magnetoresistive effect element 12 decreases by ΔR and becomes R−ΔR. Has become. In this state, the output voltage V 0
Becomes a maximum state that is larger than the value obtained by halving the voltage V.
これに対して繰り返し磁気パターン13をλ/4だけ図で
左方向に移動させると、第１の磁気抵抗効果素子１の抵
抗値がΔＲだけ減少してＲ−ΔＲとなる。このとき第２
の磁気抵抗効果素子12の抵抗値はＲとなる。そこで、こ
の状態では出力電圧V0は電圧Ｖを1/2にした値よりも小
さい極小の状態となる。On the other hand, when the magnetic pattern 13 is repeatedly moved leftward in the figure by λ / 4, the resistance value of the first magnetoresistive effect element 1 decreases by ΔR and becomes R−ΔR. At this time the second
The resistance value of the magnetoresistive effect element 12 is R. Therefore, in this state, the output voltage V 0 becomes a minimum state that is smaller than the value obtained by halving the voltage V.
また、繰り返し磁気パターン13がこれらの中間の位置
では、出力電圧V0は電圧Ｖをちょうど1/2にした値とな
る。Further, when the repeated magnetic pattern 13 is at an intermediate position between them, the output voltage V 0 has a value obtained by halving the voltage V.
第３図ａは、以上のような原理による出力電圧V0の変
化を表わしたものである。この出力電圧V0における電圧
V/2の点で順次反転するようなパルス信号（同図ｂ）を
作成すると、前述した回転量や移動位置を表わした信号
として用いることができる。FIG. 3a shows changes in the output voltage V 0 according to the above principle. The voltage at this output voltage V 0
If a pulse signal (b in the same figure) that is sequentially inverted at the point of V / 2 is created, it can be used as a signal representing the rotation amount and the moving position described above.
ところで、従来のこのような磁気抵抗効果素子回路
は、次のような問題があった。By the way, the conventional magnetoresistive effect element circuit has the following problems.
２つの端子14、15の間から出力される出力電圧V0は
不平衡出力であるために、これを取り出してパルス信号
を作成したりするためには外部に電圧V/2の基準電圧を
必要とした。Since the output voltage V 0 output between the two terminals 14 and 15 is an unbalanced output, a reference voltage of voltage V / 2 is required externally to extract it and create a pulse signal. And
磁気抵抗効果素子11、12の抵抗値の減少は数パーセ
ント程度なので、電源17の出力電圧が例えば5V程度でも
出力電圧の変動は0.01V程度の小さなものとなり、ノイ
ズが発生するような環境下では回路から出力される信号
のS/N（信号対雑音比）が悪くなるという問題があっ
た。Since the decrease in the resistance value of the magnetoresistive elements 11 and 12 is about several percent, even if the output voltage of the power supply 17 is, for example, about 5V, the fluctuation of the output voltage is as small as about 0.01V, and in an environment where noise is generated. There was a problem that the S / N (signal to noise ratio) of the signal output from the circuit deteriorates.
そこで本考案の目的は、特別の基準電圧を必要とせ
ず、しかも比較的大きな出力電圧を取り出すことのでき
る磁気抵抗効果素子回路を提供することにある。Therefore, an object of the present invention is to provide a magnetoresistive effect element circuit which does not require a special reference voltage and can take out a relatively large output voltage.
本考案では、第１および第２の磁気抵抗効果素子を平
行に配置し、それらの間隔を次の式で表わされる値ｄと
ほぼ等しくなるようにする。ただし、ここでλは第１お
よび第２の磁気抵抗効果素子と近接する繰り返し磁気信
号（繰り返し磁気パターン）の波長を表わし、ｎは零ま
たは正の整数を表わしている。In the present invention, the first and second magnetoresistive effect elements are arranged in parallel so that the distance between them is substantially equal to the value d expressed by the following equation. Here, λ represents the wavelength of the repetitive magnetic signal (repetitive magnetic pattern) that is close to the first and second magnetoresistive effect elements, and n represents zero or a positive integer.
本考案では、これら第１および第２の磁気抵抗効果素
子の接続点から両磁気抵抗効果素子に供給される電流が
ほぼ等しくなるようにカレントミラー回路を配置し、第
１の磁気抵抗効果素子がこのカレントミラー回路の電流
値を決定する抵抗となり、第２の磁気抵抗効果素子がカ
レントミラー回路の負荷抵抗となって、これら第１およ
び第２の磁気抵抗効果素子の接続点のそれぞれ他端間の
電圧を繰り返し磁気信号との位置関係を表わした出力信
号として取り出すようにしたものである。すなわち、出
力信号は両磁気抵抗効果素子の抵抗変化に基づいた差動
出力として得られることになる。 In the present invention, the current mirror circuit is arranged so that the currents supplied from the connection points of the first and second magnetoresistive effect elements to both magnetoresistive effect elements are substantially equal to each other. It becomes a resistance that determines the current value of this current mirror circuit, and the second magnetoresistive effect element acts as a load resistance of the current mirror circuit, and between the other ends of the connection points of these first and second magnetoresistive effect elements. Is repeatedly taken out as an output signal representing the positional relationship with the magnetic signal. That is, the output signal is obtained as a differential output based on the resistance change of both magnetoresistive elements.
以下、実施例につき本考案を詳細に説明する。 Hereinafter, the present invention will be described in detail with reference to embodiments.
第１図は本考案の一実施例における磁気抵抗効果素子
回路を表わしたものである。第２図と同一部分には同一
の符号を付しており、これらの説明を適宜省略する。FIG. 1 shows a magnetoresistive effect element circuit according to an embodiment of the present invention. The same parts as those in FIG. 2 are designated by the same reference numerals, and the description thereof will be appropriately omitted.
この実施例の磁気抵抗効果素子回路では第１と第２の
磁気抵抗効果素子11、12の接続点とアースとの間に電源
21を接続している。第１の磁気抵抗効果素子11における
接続点と反対側には第１の端子23とトランジスタ24のコ
レクタが接続されている。このトランジスタ24はエミッ
タが接地され、コレクタはベースと他のトランジスタ25
のベースに共通接続されている。第２の磁気抵抗効果素
子12の前記した接続点と反対側には第２の端子26とトラ
ンジスタ25のコレクタが接続されている。このトランジ
スタ25のエミッタは接地されている。２つのトランジス
タ24、25はカレントミラー回路を構成しており、第１の
磁気抵抗効果素子11がこのカレントミラー回路の電流制
限抵抗として、また第２の磁気抵抗効果素子12が負荷抵
抗として用いられる。この回路では、出力電圧V1を２つ
の端子23、26の間から取り出すようになっている。In the magnetoresistive effect element circuit of this embodiment, a power supply is provided between the connection point between the first and second magnetoresistive effect elements 11 and 12 and ground.
21 is connected. The first terminal 23 and the collector of the transistor 24 are connected to the opposite side of the connection point of the first magnetoresistive element 11. The emitter of this transistor 24 is grounded, the collector is the base and the other transistor 25.
Commonly connected to the base of. The second terminal 26 and the collector of the transistor 25 are connected to the side of the second magnetoresistance effect element 12 opposite to the above-mentioned connection point. The emitter of this transistor 25 is grounded. The two transistors 24 and 25 form a current mirror circuit. The first magnetoresistive effect element 11 is used as a current limiting resistance of this current mirror circuit, and the second magnetoresistive effect element 12 is used as a load resistance. . In this circuit, the output voltage V 1 is taken out from between the two terminals 23 and 26.
この磁気抵抗効果素子回路では一方のトランジスタ24
がダイオード接続されているので、このトランジスタ24
と第１の磁気抵抗効果素子11とで第１の磁気抵抗効果素
子11を流れる電流値が決定される。両トランジスタ24、
25が同一特性を有しているものと仮定すると、これと同
一の電流値が第２の磁気抵抗効果素子12を流れることに
なる。In this magnetoresistive element circuit, one transistor 24
Since this is a diode connection, this transistor 24
And the first magnetoresistive effect element 11 determine the value of the current flowing through the first magnetoresistive effect element 11. Both transistors 24,
Assuming that 25 has the same characteristics, the same current value will flow through the second magnetoresistive effect element 12.
そこで、第１の磁気抵抗効果素子11の抵抗値が変化し
ない状態で第２の磁気抵抗効果素子12の抵抗値が減少す
ると、端子26の電位が端子23に比べて高くなることにな
る。これとは逆に第２の磁気抵抗効果素子12の抵抗値が
変わらない状態で第１の磁気抵抗効果素子11の抵抗値が
減少すると、これに応じて第１の磁気抵抗効果素子11を
流れる電流が増加する。したがって、これに応じて第２
の磁気抵抗効果素子12を流れる電流も増加し、端子26の
電圧は低下する。この結果、両端子23、26からは繰り返
し磁気パターン（繰り返し磁気信号）13との位置関係に
応じて変動する出力電圧V1を得ることができる。Therefore, if the resistance value of the second magnetoresistive effect element 12 decreases while the resistance value of the first magnetoresistive effect element 11 does not change, the potential of the terminal 26 becomes higher than that of the terminal 23. On the contrary, when the resistance value of the first magnetoresistive effect element 11 decreases while the resistance value of the second magnetoresistive effect element 12 remains unchanged, the current flows through the first magnetoresistive effect element 11 accordingly. The current increases. Therefore, the second
The current flowing through the magnetoresistive element 12 also increases, and the voltage at the terminal 26 decreases. As a result, an output voltage V 1 that varies depending on the positional relationship with the repetitive magnetic pattern (repetitive magnetic signal) 13 can be obtained from both terminals 23 and 26.
以上説明したように、本考案によれば磁気抵抗効果素
子自体をカレントミラー回路の負荷として用いたので、
外部基準電圧が不要となり、また回路の小型化と低価格
化が可能になるという効果がある。As described above, according to the present invention, since the magnetoresistive effect element itself is used as the load of the current mirror circuit,
There is an effect that an external reference voltage becomes unnecessary, and the circuit can be downsized and the cost can be reduced.
第１図は本考案の一実施例における磁気抵抗効果素子回
路の回路図、第２図は従来提案された磁気抵抗効果素子
回路の回路図、第３図はこの従来の回路から取り出され
る信号とその整形後の波形を表わした波形図である。 11……第１の磁気抵抗効果素子、12……第２の磁気抵抗
効果素子、21……電源、23……第１の端子、24、25……
トランジスタ、26……第２の端子、V1……出力電圧。FIG. 1 is a circuit diagram of a magnetoresistive effect element circuit according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a conventionally proposed magnetoresistive effect element circuit, and FIG. 3 is a diagram showing signals extracted from this conventional circuit. It is a waveform diagram showing the waveform after the shaping. 11 …… First magnetoresistive effect element, 12 …… Second magnetoresistive effect element, 21 …… Power supply, 23 …… First terminal, 24,25 ……
Transistors, 26 ...... second terminal, V 1 ...... output voltage.
Claims (1)
れる繰り返し磁気信号の波長λに対して、 で表わされる値ｄとほぼ等しい間隔をもって第１および
第２の磁気抵抗効果素子を互いに平行に配置すると共
に、これらの磁気抵抗効果素子の接続点から両者に供給
される電流がほぼ等しくなるようにカレントミラー回路
を配置し、前記第１の磁気抵抗効果素子がこのカレント
ミラー回路の電流値を決定する抵抗となり、第２の磁気
抵抗効果素子がカレントミラー回路の負荷抵抗となっ
て、これら第１および第２の磁気抵抗効果素子の前記接
続点のそれぞれ他端間の電圧を前記繰り返し磁気信号と
の位置関係を表わした出力信号として取り出すことを特
徴とする磁気抵抗効果素子回路。1. When n is zero or a positive integer, with respect to the wavelength λ of repetitive magnetic signals that are close to each other, The first and second magnetoresistive effect elements are arranged in parallel with each other at an interval substantially equal to the value d represented by, and the currents supplied from the connection points of these magnetoresistive effect elements to both are substantially equal. A current mirror circuit is arranged, the first magnetoresistive effect element serves as a resistor that determines a current value of the current mirror circuit, and the second magnetoresistive effect element serves as a load resistance of the current mirror circuit. And a voltage across each of the other ends of the connection points of the second magnetoresistive effect element is taken out as an output signal representing a positional relationship with the repetitive magnetic signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1990003166U JPH086260Y2 (en) | 1990-01-19 | 1990-01-19 | Magnetoresistive element circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1990003166U JPH086260Y2 (en) | 1990-01-19 | 1990-01-19 | Magnetoresistive element circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0395917U JPH0395917U (en) | 1991-09-30 |
| JPH086260Y2 true JPH086260Y2 (en) | 1996-02-21 |
Family
ID=31507005
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1990003166U Expired - Lifetime JPH086260Y2 (en) | 1990-01-19 | 1990-01-19 | Magnetoresistive element circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH086260Y2 (en) |
-
1990
- 1990-01-19 JP JP1990003166U patent/JPH086260Y2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0395917U (en) | 1991-09-30 |
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