JPH0727841A - Magnetic sensor device - Google Patents
Magnetic sensor deviceInfo
- Publication number
- JPH0727841A JPH0727841A JP5194036A JP19403693A JPH0727841A JP H0727841 A JPH0727841 A JP H0727841A JP 5194036 A JP5194036 A JP 5194036A JP 19403693 A JP19403693 A JP 19403693A JP H0727841 A JPH0727841 A JP H0727841A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- sensor device
- channel
- magnetic sensor
- magnetoresistive element
- 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
Landscapes
- Measuring Magnetic Variables (AREA)
- Inspection Of Paper Currency And Valuable Securities (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁気抵抗素子を利用し
て磁性体の有無や移動等を検出する磁気センサ装置に関
するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor device for detecting the presence / absence or movement of a magnetic substance by using a magnetoresistive element.
【０００２】[0002]
【従来の技術】紙幣やキャッシュカード等の紙葉状媒体
には、磁性インク等の磁性体を用いて情報コードが書か
れており、この情報コードを読み取る磁気センサ装置の
従来例が図４に示されている。2. Description of the Related Art An information code is written on a paper-shaped medium such as a banknote or a cash card using a magnetic material such as magnetic ink, and a conventional magnetic sensor device for reading this information code is shown in FIG. Has been done.
【０００３】同図において、各検出チャンネルＣＨ1 〜
ＣＨN 毎に１対ずつ設けられている磁気抵抗素子Ｍ
Ｒ1 ，ＭＲ2 は直列に接続されており、この直列接続体
の一端側はグランド側に、他端側は電源側に接続されて
いる。磁気抵抗素子ＭＲ1 ，ＭＲ2 の近傍には、磁気抵
抗素子ＭＲ1 ，ＭＲ2 にバイアス磁界を与えるバイアス
マグネット（図示せず）が配設されている。磁性インク
等の通過により、各磁気抵抗素子ＭＲ1 ，ＭＲ2 を通る
バイアス磁界が変化するので、各磁気抵抗素子ＭＲ1 ，
ＭＲ2 の抵抗値が変化して、各磁気抵抗素子ＭＲ1 ，Ｍ
Ｒ2 の出力電圧が変化する。磁気抵抗素子ＭＲ1 ，ＭＲ
2 の直列接続体の接続部から、この出力電圧の差動出力
が交流波形として取り出され、この差動出力が各オペア
ンプ３に加えられることにより、増幅レベルシフトされ
て、各チャンネルの磁気検出信号として出力される。In the figure, each detection channel CH 1-
Magnetoresistive element M provided in pairs for each CH N
R 1 and MR 2 are connected in series, one end side of this series connection body is connected to the ground side, and the other end side is connected to the power supply side. In the vicinity of the magnetoresistive element MR 1, MR 2, bias magnets provide a bias magnetic field to the magnetoresistive element MR 1, MR 2 (not shown) is disposed. Since the bias magnetic field passing through the magnetoresistive elements MR 1 and MR 2 changes due to the passage of magnetic ink or the like, the magnetoresistive elements MR 1 and MR 1 ,
The resistance value of MR 2 changes and each magnetoresistive element MR 1 , M
The output voltage of R 2 changes. Magnetoresistive element MR 1 , MR
The differential output of the output voltage is taken out as an AC waveform from the connection part of the serial connection body of 2 , and the differential output is applied to each operational amplifier 3, whereby the amplification level is shifted and the magnetic detection signal of each channel is obtained. Is output as.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、従来の
磁気センサ装置では、各チャンネル毎に１対ずつの磁気
抵抗素子を配設しなければならないため、検出チャンネ
ル数をＮとすれば、２Ｎ個という多数の磁気抵抗素子を
必要とするので、高コストのものとなった。However, in the conventional magnetic sensor device, since one pair of magnetoresistive elements must be provided for each channel, if the number of detection channels is N, it is 2N. Since a large number of magnetoresistive elements are required, the cost is high.
【０００５】本発明は、上記課題を解決するためになさ
れたものであり、その目的は、磁気抵抗素子数を節減し
て、低コストの磁気センサ装置を提供することにある。The present invention has been made to solve the above problems, and an object thereof is to provide a low-cost magnetic sensor device by reducing the number of magnetoresistive elements.
【０００６】[0006]
【課題を解決するための手段】本発明は上記目的を達成
するために、次のように構成されている。すなわち、本
発明の磁気センサ装置は、少なくとも検出チャンネル数
の磁気抵抗素子を、電源とグランド間に直列に接続配列
し、各磁気抗素子には該磁気抵抗素子の両端電圧の差動
信号を増幅出力する差動増幅器を接続し、各差動増幅器
側の出力信号を各チャンネルの磁気検出信号としたこと
を特徴として構成されている。In order to achieve the above object, the present invention is constructed as follows. That is, in the magnetic sensor device of the present invention, magnetic resistance elements of at least the number of detection channels are connected and arranged in series between the power supply and the ground, and each magnetic resistance element amplifies the differential signal of the voltage across the magnetic resistance element. A differential amplifier for output is connected, and the output signal of each differential amplifier side is used as a magnetic detection signal of each channel.
【０００７】[0007]
【作用】磁性インク等の磁性体が通過すると、これに対
応する検出チャンネルの磁気抵抗素子を通る磁界が変化
するため、該磁気抵抗素子の抵抗値が変化し、該磁気抵
抗素子の出力電圧が変化する。この出力電圧の変化が差
動増幅器により該磁気抵抗素子の両端電圧の差動信号と
して増幅されて取り出され、この増幅された差動信号が
各チャンネルの磁気検出信号として出力される。When a magnetic substance such as magnetic ink passes, the magnetic field passing through the corresponding magnetoresistive element of the detection channel changes, so that the resistance value of the magnetoresistive element changes and the output voltage of the magnetoresistive element changes. Change. The change in the output voltage is amplified and taken out as a differential signal of the voltage across the magnetoresistive element by the differential amplifier, and the amplified differential signal is output as the magnetic detection signal of each channel.
【０００８】[0008]
【実施例】以下、本発明の実施例を図面に基づいて説明
する。図１には、本発明に係る磁気センサ装置の一実施
例の回路構成が示されている。駆動電源としての定電流
電源とグランドＧＮＤの間には、検出チャンネル数Ｎの
磁気抵抗素子ＭＲ1 〜ＭＲN が、各検出チャンネルに１
個ずつ配設されて直列に接続されている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit configuration of an embodiment of a magnetic sensor device according to the present invention. Between the constant-current power supply and the ground GND as a driving power source, a magnetoresistive element MR 1 ～MR N detection channel number N is, in each detection channel 1
They are arranged one by one and connected in series.
【０００９】各チャンネル毎の磁気抵抗素子ＭＲ1 〜Ｍ
ＲN の両端電圧が抵抗体Ｒ1 ，Ｒ2を介して各差動増幅
器Ｂ1 〜ＢN に加えられており、これら差動増幅器Ｂ1
〜ＢN の出力側から、各ＭＲ1 〜ＭＲN の両端電圧の差
動増幅信号が、各チャンネルの磁気検出信号として出力
されるよう構成されている。Magnetoresistive elements MR 1 to M for each channel
The voltage across R N is applied to each differential amplifier B 1 to B N via resistors R 1 and R 2 , and these differential amplifier B 1
From the output side of .about.B N, differential amplified signal voltage across the MR 1 ~MR N is configured to be outputted as a magnetic detection signals of the respective channels.
【００１０】前記差動増幅器Ｂ1 〜ＢN の出力側は、そ
れぞれコンデンサＣと抵抗体Ｒ5 との直列接続体よりな
る微分回路が接続され、この微分回路の出力側は、反転
増幅器として機能する各オペアンプＤ1 〜ＤN の反転入
力端子側に接続されている。これらオペアンプＤ1 〜Ｄ
N の非反転入力端子側は、電圧Ｖr が印加されて、オペ
アンプＤ1 〜ＤN の出力側からは増幅レベルシフトされ
た磁気検出信号ＶO1〜ＶONが出力される構成となってい
る。The output side of the differential amplifiers B 1 to B N is connected to a differentiating circuit composed of a series connection of a capacitor C and a resistor R 5, and the output side of this differentiating circuit functions as an inverting amplifier. The operational amplifiers D 1 to D N are connected to the inverting input terminal side. These operational amplifiers D 1 to D
The voltage V r is applied to the non-inverting input terminal side of N , and the amplified level-shifted magnetic detection signals V O1 to V ON are output from the output sides of the operational amplifiers D 1 to D N. .
【００１１】上記構成の本実施例において、磁性インク
等の磁性体の通過により、その通過に対応した検出チャ
ンネルi の磁気抵抗素子ＭＲi を通るバイアス磁界が変
化するため、磁気抵抗素子ＭＲi の抵抗値および出力電
圧が変化する。磁気抵抗素子ＭＲi の両端電圧が差動増
幅器Ｂi に加えられることにより、両端電圧の差動信号
が増幅され、この増幅された差動信号ＶDiが、図２の
（ａ）に示すようなi のチャンネルの磁気検出信号とし
て差動増幅器Ｂi から出力する。[0011] In this embodiment having the above configuration, by the passage of magnetic material such as magnetic inks, since the bias magnetic field through the magnetoresistive element MR i detection channels i corresponding to the passage changes, the magnetoresistive element MR i The resistance value and output voltage change. By applying the voltage across the magnetoresistive element MR i to the differential amplifier B i , the differential signal across the voltage is amplified, and the amplified differential signal V Di is as shown in FIG. It is output from the differential amplifier B i as a magnetic detection signal of the i channel.
【００１２】次に、このチャンネルの磁気検出信号は、
コンデンサＣと抵抗体Ｒ5 からなる微分回路により微分
処理されて、オペアンプＤi に加えられることにより、
同図の（ｂ）に示すように反転増幅され、かつ、レベル
シフトされる。オペアンプＤi からは、このように増幅
レベルシフトされたチャンネルi の磁気検出信号ＶOiが
出力される。Next, the magnetic detection signal of this channel is
After being differentiated by a differentiating circuit composed of the capacitor C and the resistor R 5, and applied to the operational amplifier D i ,
Inversion amplification is performed and level shifting is performed as shown in FIG. From the operational amplifier D i , the magnetic detection signal V Oi of the channel i thus amplified and level-shifted is output.
【００１３】本実施例によれば、各検出チャンネルにお
ける磁性インク等の磁性体の通過は、この通過によって
生ずる各磁気抵抗素子ＭＲi の抵抗値の変化による、該
磁気抵抗素子ＭＲi の両端電圧を増幅出力することによ
って検出される。したがって、各検出チャンネルに対応
する磁気抵抗素子は、１個のみ配設すれば磁性インク等
の通過を検出できることとなり、従来、各検出チャンネ
ル毎に１対ずつの磁気抵抗素子が必要だったのに比べ、
磁気抵抗素子の必要数は半減し、磁気センサ装置の低コ
スト化が達成される。According to the present embodiment, the passage of the magnetic substance such as magnetic ink in each detection channel is caused by the change in the resistance value of each magnetoresistive element MR i caused by the passage, and the voltage across the magnetoresistive element MR i . Is amplified and output. Therefore, if only one magnetoresistive element corresponding to each detection channel is provided, the passage of magnetic ink or the like can be detected, and conventionally one pair of magnetoresistive elements was required for each detection channel. compared,
The required number of magnetoresistive elements is halved, and the cost of the magnetic sensor device is reduced.
【００１４】また、駆動電源が定電流電源であるため、
他の検出チャンネルの磁気抵抗素子が、磁性インクの通
過を検知して抵抗値が変化しても、検出チャンネルi の
磁気抵抗素子ＭＲi には、常に一定の電流が流れるの
で、磁気抵抗素子ＭＲi の両端電圧の差動増幅信号から
は、他のチャンネルの磁気抵抗素子の抵抗値の変化の影
響を受けない安定した信頼性の高い磁気検出信号が得ら
れる。Further, since the driving power source is a constant current power source,
Even if the magnetoresistive element of the other detection channel detects the passage of the magnetic ink and the resistance value changes, a constant current always flows through the magnetoresistive element MR i of the detection channel i. From the differentially amplified signal of the voltage across i, a stable and highly reliable magnetic detection signal that is not affected by the change in the resistance value of the magnetoresistive element of the other channel can be obtained.
【００１５】なお、本発明は上記実施例に限定されるこ
とはなく、様々な実施の態様を採り得る。例えば、上記
実施例では、駆動電源を定電流電源にしたが、図３に示
すように、定電圧電源としてもよい。この場合には、磁
気抵抗素子ＭＲ1 〜ＭＲN の直列接続体の定電圧電源側
とグランド側にそれぞれ１個ずつのダミーの磁気抵抗素
子ＭＲＤが必要となるので、磁気センサ装置全体では、
磁気抵抗素子は検出チャンネル数Ｎ＋２個必要となる。
しかし、この場合にも、磁気抵抗素子数が検出チャンネ
ル数Ｎの２倍必要な従来例に比べれば、磁気抵抗素子数
は少なくて済むため、磁気センサ装置の低コスト化が達
成される。The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, in the above embodiment, the driving power supply is a constant current power supply, but it may be a constant voltage power supply as shown in FIG. In this case, since the magnetoresistive element MR 1 ~MR N series connection of a constant voltage power source side and the dummy magnetoresistive element MRD of the ground side one by one each is required, the entire magnetic sensor device,
The number of detection channels N + 2 is required for the magnetoresistive element.
However, also in this case, the number of magnetoresistive elements is smaller than that of the conventional example in which the number of magnetoresistive elements is twice the number N of detection channels, so that the cost of the magnetic sensor device can be reduced.
【００１６】また、上記実施例の回路構成におけるコン
デンサＣと、抵抗体Ｒ5 よりなる微分回路を省略しても
よく、さらに、各磁気抵抗素子ＭＲ1 〜ＭＲN の両端電
圧を取り出すものであれば、差動増幅側の回路は、上記
実施例の回路構成に限定されるものではない。[0016] long as it takes out the capacitor C in the circuit configuration of the above embodiment, may be omitted differentiating circuit consisting of resistor R 5, further the voltage across the magnetoresistive element MR 1 ~MR N For example, the circuit on the differential amplification side is not limited to the circuit configuration of the above embodiment.
【００１７】[0017]
【発明の効果】本発明は、被検出体である磁性体の移動
を、検出チャンネル毎に１個ずつ直列に接続配列した磁
気抵抗素子の両端電圧の差動信号を増幅して検出するよ
う構成しているので、検出チャンネル毎に１対ずつ磁気
抵抗素子を必要とした従来例に比べて、磁気抵抗素子数
はほぼ半数でよいため、低コストな磁気センサ装置を提
供できる。According to the present invention, the movement of the magnetic substance as the object to be detected is detected by amplifying the differential signal of the voltage across the magnetoresistive elements connected in series for each detection channel. Therefore, the number of magnetoresistive elements may be about half as compared with the conventional example in which one pair of magnetoresistive elements is required for each detection channel, so that a low-cost magnetic sensor device can be provided.
【図１】本発明に係る磁気センサ装置の一実施例を示す
回路構成図である。FIG. 1 is a circuit configuration diagram showing an embodiment of a magnetic sensor device according to the present invention.
【図２】同実施例における磁気検出信号の変換過程を示
す信号波形図である。FIG. 2 is a signal waveform diagram showing a conversion process of a magnetic detection signal in the example.
【図３】本発明に係る磁気センサ装置の他の実施例を示
す回路構成図である。FIG. 3 is a circuit configuration diagram showing another embodiment of the magnetic sensor device according to the present invention.
【図４】従来の磁気センサ装置の回路構成を示す説明図
である。FIG. 4 is an explanatory diagram showing a circuit configuration of a conventional magnetic sensor device.
Ｂ1 〜ＢN 差動増幅器 ＭＲ1 〜ＭＲN 磁気抵抗素子B 1 to B N differential amplifier MR 1 to M N magnetoresistive element
Claims (1)
素子を、電源とグンド間に直列に接続配列し、各磁気抗
素子には該磁気抵抗素子の両端電圧の差動信号を増幅出
力する差動増幅器を接続し、各差動増幅器側の出力信号
を各チャンネルの磁気検出信号とした磁気センサ装置。1. A differential amplifier in which magnetic resistance elements having at least the number of detection channels are connected and arranged in series between a power supply and a ground, and each magnetic resistance element amplifies and outputs a differential signal of a voltage across the magnetic resistance elements. And a magnetic sensor device in which the output signal of each differential amplifier side is used as a magnetic detection signal of each channel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5194036A JPH0727841A (en) | 1993-07-09 | 1993-07-09 | Magnetic sensor device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5194036A JPH0727841A (en) | 1993-07-09 | 1993-07-09 | Magnetic sensor device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0727841A true JPH0727841A (en) | 1995-01-31 |
Family
ID=16317873
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5194036A Pending JPH0727841A (en) | 1993-07-09 | 1993-07-09 | Magnetic sensor device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0727841A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008524571A (en) * | 2004-12-17 | 2008-07-10 | エス．エヌ．エール．ルールマン | Current loop position sensor and rotary bearing including the same |
-
1993
- 1993-07-09 JP JP5194036A patent/JPH0727841A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008524571A (en) * | 2004-12-17 | 2008-07-10 | エス．エヌ．エール．ルールマン | Current loop position sensor and rotary bearing including the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4712144A (en) | Method and apparatus for reading recorded data by a magnetoresistive head | |
| KR940022502A (en) | Lead and Light Integrated Circuits | |
| JP3271633B2 (en) | Position detection circuit | |
| JP4697498B2 (en) | Magnetic sensor device | |
| JPH08327677A (en) | Detection circuit and detection method for capacitive sensor | |
| JPH0727841A (en) | Magnetic sensor device | |
| US6219194B1 (en) | MR head read amplifier with improved write to read recovery time | |
| GB1589682A (en) | Method and means for tracking magnetic tracks | |
| EP0121950B1 (en) | Magnetic field sensor | |
| JP4281124B2 (en) | Peak detector | |
| JP3230230B2 (en) | Detector | |
| US6920002B2 (en) | Reproducing amplifier and magnetic recording and reproducing apparatus employing the reproducing amplifier | |
| JPS5868615A (en) | Output circuit of magnetic type rotary encoder | |
| JP3195019B2 (en) | Origin signal detector | |
| JPH02134575A (en) | Power supply current measuring circuit | |
| CN111624532B (en) | Magnetoresistive sensor system | |
| US6400627B1 (en) | Sensing circuit for magnetic memory unit | |
| JPH0569631U (en) | Capacity type electromagnetic flow meter | |
| JPS6035711B2 (en) | magnetic signal detection device | |
| JPH0325238Y2 (en) | ||
| JPH0458174A (en) | Magnetic sensor for detecting marking | |
| KR900007370Y1 (en) | Kind detecting circuit for the magnetic tape | |
| JPH0487003A (en) | Signal detecting circuit for magneto-resistance effect head | |
| KR970010984B1 (en) | Metal specimen detecting apparatus | |
| JPH03246418A (en) | Position detecting device |