JPH03134514A - Magnetoresistance effect element - Google Patents
Magnetoresistance effect elementInfo
- Publication number
- JPH03134514A JPH03134514A JP1272826A JP27282689A JPH03134514A JP H03134514 A JPH03134514 A JP H03134514A JP 1272826 A JP1272826 A JP 1272826A JP 27282689 A JP27282689 A JP 27282689A JP H03134514 A JPH03134514 A JP H03134514A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- transistor
- zener diode
- zener
- base
- 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.)
- Pending
Links
- 230000000694 effects Effects 0.000 title claims abstract description 9
- 230000002265 prevention Effects 0.000 claims description 7
- 238000010586 diagram Methods 0.000 description 5
- 238000001514 detection method Methods 0.000 description 4
- 230000020169 heat generation Effects 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 238000007493 shaping process Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
Landscapes
- Transmission And Conversion Of Sensor Element Output (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明はモータの回転制御２位置制御に使用される磁気
式エンコーダの磁気抵抗効果素子（磁気センサ）に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetoresistive element (magnetic sensor) of a magnetic encoder used for two-position rotational control of a motor.
従来の技術
磁気式エンコーダは、第３図に示すようにモータ３のシ
ャフトに固定された円筒形の磁気ドラム１と、この磁気
ドラム１と所定のギャップを隔てて対向配置された磁気
抵抗効果素子２とによシ構成されている。As shown in FIG. 3, a conventional magnetic encoder includes a cylindrical magnetic drum 1 fixed to the shaft of a motor 3, and a magnetoresistive element placed opposite the magnetic drum 1 with a predetermined gap therebetween. It is composed of two parts.
磁気ドラム１には、磁気抵抗効果素子２と対向する円軌
道に沿って磁化パターン（図示せず）が多極着磁されて
いる。モータ３により磁気ドラム１が回転することで、
磁気抵抗効果素子２に対向する磁極（磁化パターン）が
変化し、それに伴い磁気抵抗効果素子２の抵抗値が変化
する。この原理をもとに磁気抵抗効果素子は信号検出を
行う。The magnetic drum 1 is magnetized with a multipolar magnetization pattern (not shown) along a circular orbit facing the magnetoresistive element 2 . When the magnetic drum 1 is rotated by the motor 3,
The magnetic pole (magnetization pattern) facing the magnetoresistive element 2 changes, and the resistance value of the magnetoresistive element 2 changes accordingly. Based on this principle, the magnetoresistive element performs signal detection.
磁気抵抗効果素子２で検出された信号（第５図＋ＩＬ）
〜（Ｃ））は、そのまま第４図に示すような電子回路に
とりかこまれ、波形増幅が行われた後に波形整形回路を
通してデジタル信号（第６図（！Ｌ）〜（ｆ））に変換
される（第５図（ＩＬ）〜（Ｑ）はそれぞれ（（ｍｌ−
（ｆ）に対応している）。Signal detected by magnetoresistive element 2 (Fig. 5 + IL)
- (C)) are directly surrounded by an electronic circuit as shown in Figure 4, and after waveform amplification, are converted into digital signals (Figure 6 (!L) - (f)) through a waveform shaping circuit. (Figure 5 (IL) to (Q) are respectively ((ml-
(corresponds to (f)).
発明が解決しようとする課題
ところで、磁気抵抗効果素子２の電源ラインには定格電
圧を印加しておくことが必要で、定格以上の電圧がかけ
られた場合、磁気抵抗効果素子２そのものが破壊されて
しまったり、過負荷による発熱で磁気抵抗効果素子の抵
抗変化率が変化し、信号検出能力の低下という問題があ
る。Problem to be Solved by the Invention By the way, it is necessary to apply a rated voltage to the power supply line of the magnetoresistive element 2, and if a voltage higher than the rated voltage is applied, the magnetoresistive element 2 itself will be destroyed. There is a problem in that the resistance change rate of the magnetoresistive element changes due to heat generation due to overload, and the signal detection ability deteriorates.
本発明の目的は、磁気抵抗効果素子２の電源ラインに定
格以上の電圧が印加されたときでも、磁気抵抗効果素子
２が正常な動作を行えるようにすることである。An object of the present invention is to enable the magnetoresistive element 2 to operate normally even when a voltage higher than the rated voltage is applied to the power supply line of the magnetoresistive element 2.
課題を解決するための手段
上記目的を達成するために本発明の磁気抵抗効果素子は
、電源ラインに過電圧印加防止回路を備えたものである
。Means for Solving the Problems In order to achieve the above object, the magnetoresistive element of the present invention is provided with an overvoltage application prevention circuit in the power supply line.
作用
上記した構成により、磁気抵抗効果素子の信号検出動作
が安定したものになる。Effect: With the above-described configuration, the signal detection operation of the magnetoresistive element becomes stable.
実施例
以下、図面に示す実施例に基づいて本発明の詳細な説明
する。EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.
第１図は本発明における磁気抵抗効果素子の電源ライン
用過電圧印加防止回路を示したもので、第２図は第１図
の回路を用いたとき、電源電圧と磁気抵抗効果素子に印
加される電圧との関係を示した特性図である。Figure 1 shows an overvoltage application prevention circuit for the power line of the magnetoresistive element in the present invention, and Figure 2 shows the power supply voltage and the voltage applied to the magnetoresistive element when the circuit of Figure 1 is used. FIG. 3 is a characteristic diagram showing the relationship with voltage.
第１図に示す過電圧印加防止回路はツェナー・ダイオー
ドを使用した定電圧回路で、トランジスタのベースとグ
ランドの間にツェナー・ダイオードを配置し、コレクタ
側に入力端子、エミッタ側に出力端子をそれぞれもって
いる。抵抗Ｒは入力電圧Ｗｉｎと出力電圧ＶＯｕｔ、ト
ランジスタのペース電流工、および、ツェナー・ダイオ
ード電流Ｘｚできまり、
Ｒ＝（Ｗｉｎ −ｖｏｕｔ ）／（Ｉ Ｂ＋Ｉ ｚ ）
となる。The overvoltage application prevention circuit shown in Figure 1 is a constant voltage circuit using a Zener diode.The Zener diode is placed between the base of the transistor and the ground, and the input terminal is on the collector side and the output terminal is on the emitter side. There is. The resistance R is determined by the input voltage Win, the output voltage VOut, the transistor pace current, and the Zener diode current Xz, R = (Win - vout ) / (I B + I z )
becomes.
そして出力電圧Ｖｏｕｔは、ツェナー・ダイオードの抵
抗ｒｇ、ツェナー電圧ｖｚを用いて、Ｖｏｕｔ ＝（Ｗ
ｉｎ−ｒ、−１−ｖｚ−Ｒ）／ｒｚ＋Ｒとなる。しかし
ながら、実際の出力電圧はこれからトランジスタのベー
ス・エミッタ電圧Ｖ□を差し引いた値（ｖｏｕｔ ’
ａｘ）となる。Then, the output voltage Vout is calculated using the resistance rg of the Zener diode and the Zener voltage vz, as follows: Vout = (W
in-r, -1-vz-R)/rz+R. However, the actual output voltage is the value obtained by subtracting the transistor base-emitter voltage V□ (vout '
ax).
したがって出力電圧はツェナー・ダイオードのツェナー
電圧ｖｚで決まることになる。ツェナーダイオードには
逆方向印加電圧が増加すると、ある電圧値から急激に逆
方向電流が流れだしてプレクダウンを起こすツェナー効
果という現象がある。Therefore, the output voltage is determined by the Zener voltage vz of the Zener diode. Zener diodes have a phenomenon called the Zener effect, in which when the reverse applied voltage increases, a reverse current suddenly starts flowing from a certain voltage value, causing pre-kdown.
このときの電圧をツェナー電圧と呼ぶ。このため、ツェ
ナー・ダイオードｚＤのツェナー電圧ｖ２を磁気抵抗効
果素子の定格電圧（第２図において５Ｖ ）、！−ト；
＞ンジスタのベース・エミッタ電圧ＶＢＩを加えた値（
第２図においてｓ、ｅＶ）に設定しておけば、第２図に
示すように入力端子ｖｉｎに過電圧（ｓ、ｅＶ以上）が
印加されても、ツェナー効果によりトランジスタのベー
ス電圧バ一定に保たれ、磁気抵抗効果素子には常に定格
の電圧（６ｖ）が印加されるようになる。The voltage at this time is called Zener voltage. Therefore, the Zener voltage v2 of the Zener diode zD is set to the rated voltage of the magnetoresistive element (5V in FIG. 2), ! -t;
＞The sum of the resistor's base-emitter voltage VBI (
If the voltage is set to s, eV in Figure 2, even if an overvoltage (more than s, eV) is applied to the input terminal vin as shown in Figure 2, the Zener effect will keep the base voltage of the transistor constant. As a result, the rated voltage (6V) is always applied to the magnetoresistive element.
発明の効果
以上のように本発明は、電源ラインに過電圧印加防止回
路を備えることで、磁気抵抗効果素子の破壊を防ぐこと
ができ、また、発熱による磁気抵抗効果素子の抵抗変化
率の変化を無くし、信号検出動作を安定なものにする仁
とになる。Effects of the Invention As described above, the present invention can prevent destruction of the magnetoresistive element by providing an overvoltage application prevention circuit in the power supply line, and can also prevent changes in the resistance change rate of the magnetoresistive element due to heat generation. This is the key to making the signal detection operation stable.
第１図は本発明における磁気抵抗効果素子の電源ライン
に備える過電圧印加防止回路の回路図、第２図は第１図
における入力電圧Ｗｉｎと磁気抵抗効果素子の電源ライ
ンに印加される電圧Ｖ ｏｕｔとの関係を表した特性図
、第３図は従来の磁気式エンコーダの構成例を示す模式
図、第４図は磁気抵抗効果素子から信号を取り出すため
に用いる電子回路の１例を示す回路図、第５図は第４図
に示す電子回路に入力する信号と、それを波形整形した
信号の波形図である。
ＺＤ・・・・・・ツェナー・ダイオード、Ｔｒ・・・・
・・トランジスタ、ＭＲ・・・・・・磁気抵抗効果素子
。Fig. 1 is a circuit diagram of an overvoltage application prevention circuit provided in the power supply line of the magnetoresistive element according to the present invention, and Fig. 2 shows the input voltage Win in Fig. 1 and the voltage V out applied to the power supply line of the magnetoresistive element. Figure 3 is a schematic diagram showing a configuration example of a conventional magnetic encoder, Figure 4 is a circuit diagram showing an example of an electronic circuit used to extract signals from a magnetoresistive element. , FIG. 5 is a waveform diagram of a signal input to the electronic circuit shown in FIG. 4 and a signal obtained by shaping the signal. ZD... Zener diode, Tr...
...Transistor, MR... Magnetoresistive element.
Claims (2)
特徴とする磁気抵抗効果素子。(1) A magnetoresistive element characterized in that a power supply line is equipped with an overvoltage application prevention circuit.
グランドの間にツェナー・ダイオードを配置し、トラン
ジスタのコレクタ側に入力端子、エミッタ側に出力端子
をもっていることを特徴とする請求項１記載の磁気抵抗
効果素子。(2) The overvoltage application prevention circuit has a Zener diode placed between the base of the transistor and the ground, and has an input terminal on the collector side of the transistor and an output terminal on the emitter side. Resistance effect element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1272826A JPH03134514A (en) | 1989-10-19 | 1989-10-19 | Magnetoresistance effect element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1272826A JPH03134514A (en) | 1989-10-19 | 1989-10-19 | Magnetoresistance effect element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03134514A true JPH03134514A (en) | 1991-06-07 |
Family
ID=17519306
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1272826A Pending JPH03134514A (en) | 1989-10-19 | 1989-10-19 | Magnetoresistance effect element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03134514A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0575686U (en) * | 1992-02-17 | 1993-10-15 | 旭化成工業株式会社 | Temperature correction circuit |
-
1989
- 1989-10-19 JP JP1272826A patent/JPH03134514A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0575686U (en) * | 1992-02-17 | 1993-10-15 | 旭化成工業株式会社 | Temperature correction circuit |
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