JPS6191577A - Rotary magnetic field detector - Google Patents

Abstract

PURPOSE:To eliminate changes in the detection sensitivity due to variations in the temperature, by connecting each one end of two magnetic resistance elements arranged at angles shifted properly to a common potential while the other end thereof connected to independent constant current sources to detect the potential difference. CONSTITUTION:Two magnetic resistance elements MR1 and MR2 are built on the surface of a substrate 4 in a zigzag pattern in such a manner as to be at the right angle to each other along the length of the zigzag pattern. A circular magnet 6 magnetized diametrically is fastened at the upper end of a rotating shaft 5 to generate a magnetic field turning within the surface of the substrate 4 as the shaft 5 rotates and the electric resistances of the elements MR1 and MR2 change according to the angle of the rotary magnetic field. Then, respective one ends of the elements MR1 and MR2 are connected to the ground GND of a common terminal while constant current sources 7 and 8 are connected to respective other ends thereof to run constant currents I1 and I2. The constant currents I1 and I2 are so set that the voltage drops of the elements equal when the angle of the magnetic field theta=45 deg.. So, when the difference in the terminal voltage between both the elements is detected with a comparator 3, the resulting value is free from the temperature as it contains no portion corresponding to changes in the temperature of the resistance value according to a specified formula.

Description

【発明の詳細な説明】 イ１１発明の目的 イー１．　産業上の利用分野 この発明は磁気抵抗素子を用いて回転磁界全検出する装
置の改良に関する〇 イー２６　　　従　　来　　技　　術 特開昭５０−２ｇ７ざり号公報に示されている磁界検出
素子は、第６図のように、ジグザグ状のパターンを有す
る磁気抵抗素子（ＭＨＩ）　、！：　（ｌｉ４Ｒ２）を
同一平面内に９０度向！８をずらして配置し、画素子を
電気的に直列に接続したものである。[Detailed Description of the Invention] A11 Purpose of the Invention E1. INDUSTRIAL APPLICATION FIELD This invention relates to the improvement of a device for detecting the entire rotating magnetic field using a magnetoresistive element. As shown in Figure 6, a magnetoresistive element (MHI) with a zigzag pattern! : (li4R2) in the same plane at 90 degrees! 8 are arranged in a staggered manner, and the pixel elements are electrically connected in series.

この磁気抵抗素子に、前記同一平面（第３図の紙面ン内
で角度θの方向の磁界を矢印Ｂで示すように印加すると
、素子（ＭＨＩ）の電気抵抗斑（θ）は磁界の角度θに
応じて変化し、 Ｒ１（０）−／’ＪＬ８　ｉ　ｎ’θ＋ρ、ＩＣＯ♂θ
＝ρユ＋（ρ１１−ρ、）ｃｏ計θ であられされる。When a magnetic field in the direction of angle θ is applied to this magnetoresistive element in the same plane (the plane of the paper in FIG. 3 as shown by arrow B), the electric resistance spot (θ) of the element (MHI) is R1(0)-/'JL8 in'θ+ρ, ICO♂θ
=ρyu+(ρ11-ρ,)cototalθ.

ρ４素子（ＭＲＩ）のジグザグパターンの長手方向に対
して磁界Ｂの向きが直角のときの電気抵抗で、ρ１．は
平行のときの電気抵抗であり、ρ、１−ρ、工△ρ とおくと、 Ｒ）（θ）＝　ρ上　＋Δρ　ｃｏｓ”６　　　　　　
　　　　　　・　　・　　・　（１）となる。ρ1 is the electrical resistance when the direction of the magnetic field B is perpendicular to the longitudinal direction of the zigzag pattern of the ρ4 element (MRI). is the electrical resistance when parallel, and if we set ρ, 1−ρ, and Δρ, then R)(θ)=ρ on +Δρ cos”6
・ ・ ・ (1) becomes.

素子（ＭＲ２）についても、そのジグザグパターンが素
子（ＭＲＩ）と同一形状であるから、その電気抵抗Ｒ２
（θ）は、同様に Ｒ２（θ〕＝ρよ＋Δρｓｉｎ”　θ　　　　　　　　
　　　　　　　−−−（２）となる。Regarding the element (MR2), since its zigzag pattern has the same shape as the element (MRI), its electrical resistance R2
(θ) is similarly R2(θ]=ρ+Δρsin” θ
---(2) becomes.

画素子（ＭＨＩ）と（ＭＲ２）の直列接続の一端全接地
（ＧＮＤ）シ、他端（１）に電圧ｖｉｎ’ｊｚかけると
、画素子の接続点（２）は の電圧となる。When one end of the series connection of the pixel element (MHI) and (MR2) is all grounded (GND) and the voltage vin'jz is applied to the other end (1), the voltage at the connection point (2) of the pixel element becomes .

これに、前記（１７式と（２）式を代入すると、となる
。Substituting the above equation (17) and equation (2) into this, we get the following.

ρ工＋１△ρユρ。ρ engineering + 1△ρyuρ.

とすると、 となる。Then, becomes.

即？）ＣＯ８２０卸となる磁界が印加されていると、つ
まり画素子のジグザグパターンの長手方向に対してｔｌ
ｓ度の角度全磁界Ｂがなしているときには、”ｏハＶｉ
ｎの１／２となる。　そして、磁界Ｂが、紙面内で回転
したとき電圧■。の変化分は最大１ｍがとなる。Immediately? ) When a magnetic field of CO820 is applied, that is, tl is applied in the longitudinal direction of the zigzag pattern of the pixel element.
When the total magnetic field B is at an angle of s degrees, "oha Vi
It becomes 1/2 of n. Then, when the magnetic field B rotates within the plane of the paper, the voltage ■. The maximum change in distance is 1m.

磁界の角度θに対する出力電圧■。の変化は第７図のよ
うに、正弦波状に変化し、その振巾び１ｗ４Ｒ０，全振
巾はΔρＶｉｎ／２ρＯ：ｖ、ｎとなる。Output voltage vs. magnetic field angle θ■. changes in a sinusoidal manner as shown in FIG. 7, and its amplitude is 1w4R0, and the total amplitude is ΔρVin/2ρO:v,n.

出力電圧ｖＯの変化を検出するには第ｇ図のように、素
子（ＭＲＩ　）、　（ＭＲ２）に固定抵抗（Ｒ１）と（
Ｒ２）全接続してブリッジ回路を構成し、その不平衡電
圧全比較器（又は演算増幅器）（３）で検出していた。To detect the change in the output voltage vO, as shown in Fig.
R2) All connections were made to form a bridge circuit, and the unbalanced voltage was detected by all comparators (or operational amplifiers) (3).

このように、出力電圧Ｖｏ’を検出することで磁界Ｂの
回転全検出していた。　第７図は検出用電気回路の異な
る従来技術で、画素子（ＭＲｌ）と（ＭＲ，ｌりの各一
端を接地（ＧＮＤ）　Ｌ、各他端金それぞれ固定抵抗器
（Ｒ１）と（Ｒｇ）’を介して電圧Ｖｉｎにｆｆｌ続１
．、テブリッジ回路全構成したもので、素子（ＭＲＩ）
と抵抗（Ｒ１）との接続点の電圧ＶＯＩ゛と、素子（Ｍ
ＲＩ　）と抵抗（Ｒ２）との接続点の電圧Ｖ。２の差を
比較器（３）で検出するものである。In this manner, the entire rotation of the magnetic field B is detected by detecting the output voltage Vo'. Figure 7 shows a conventional technology with a different electric circuit for detection, in which one end of each of the pixel element (MRl) is grounded (GND), and the other end is connected to a fixed resistor (R1) and (Rg). 'ffl connected to voltage Vin through 1
．． , complete Tebridge circuit configuration, element (MRI)
and the voltage VOI at the connection point between the resistor (R1) and the element (M
The voltage V at the connection point between RI ) and the resistor (R2). The comparator (3) detects the difference between the two.

イー８．　本発明が解決しようとする問題点磁気抵抗素
子（ＭＨＩ）、（ＭＲ２）　’ｅ　ｇ　ＯＮｘ　　２０
Ｃ。E8. Problems to be solved by the present invention Magnetoresistive element (MHI), (MR2) 'e g ONx 20
C.

（重険％）合金からなる磁気抵抗膜で構成したとすると
、温度が変化すると電気抵抗が変化しその抵抗温度係数
は正の値で、約０３％１０Ｃである。(Severe risk %) If it is constructed from a magnetoresistive film made of an alloy, the electrical resistance changes as the temperature changes, and the temperature coefficient of resistance is a positive value of about 0.3% 10C.

従って、温度が夕ｏＯｃ上昇すると前記（３）式のＲ０
が／夕％大きくなる。　そのため、（４）式で示す変化
分 となり、約ｆ７％に低下する。Therefore, when the temperature rises in the evening oOc, R0 of the above equation (3)
% becomes larger. Therefore, the amount of change is as shown by equation (4), which is about f7%.

第７図に、接続点（２）の電圧■０が磁界の同＠０によ
り変化する様子全示すが、その全振幅Ｖｍが湿度上昇に
よって破線に示すようＶ／に低下する。FIG. 7 shows how the voltage 0 at the connection point (2) changes due to the magnetic field 0, and its total amplitude Vm decreases to V/ as shown by the broken line due to the increase in humidity.

このように従来技術では、温度が変化すると磁気抵抗素
子の抵抗値ρＯが変化して、磁界を検出する感度が変化
する欠点があった。As described above, the conventional technology has the disadvantage that when the temperature changes, the resistance value ρO of the magnetoresistive element changes, and the sensitivity for detecting the magnetic field changes.

第り図の従来技術の場合でも、電圧ＶｏｌとＶｏ２が温
度上昇により第１Ｏ図（Ａ）と（Ｂ）図の破線に示すよ
うに変化する。　両電圧Ｖｏｌ、Ｖｏ２共温度上昇前の
実線のときに比較して、温度上昇後は中心値が上昇し、
振幅が低下する。　中心１直の上昇は第７図の回路構成
でＶｏｌとＶｏ２の差？検出するときに打ち消されるが
、振幅の低下分は感度の低下として問題となり、第ざ図
の場合と同様に欠点となる。Even in the case of the prior art shown in FIG. 1, the voltages Vol and Vo2 change as shown by the broken lines in FIGS. 10(A) and 1(B) due to temperature rise. Compared to the solid lines before the temperature rise for both voltages Vol and Vo2, the center value increases after the temperature rise,
Amplitude decreases. Is the rise in center 1st shift the difference between Vol and Vo2 in the circuit configuration shown in Figure 7? Although this is canceled out during detection, the decrease in amplitude becomes a problem as a decrease in sensitivity, which is a drawback as in the case of FIG.

第７０図で、Ｖｌｍ、　Ｖ２ｍは電圧Ｖｏｌ　、　Ｖ、
ｏ２の角度θの変化に伴なう変動分の全振幅で、温度が
上昇したときの全振幅はそれぞれＶ１ｍ’、ｖ２ｍ′で
示しており、第７図の検出回路でＶｏｌとｖ０２の差金
とることで、差の全振幅は （Ｖｏｌ　　Ｖｏ２）　全振幅＝仝−ａ　Ｖ　ｉ　ｎ２
ρ となり、第７図、第ｇ図の場合と同じになる。In Fig. 70, Vlm and V2m are voltages Vol, V,
The total amplitude of the variation due to the change in the angle θ of o2, and the total amplitude when the temperature rises are shown as V1m' and v2m', respectively, and the difference between Vol and v02 is obtained by the detection circuit in Figure 7. Therefore, the total amplitude of the difference is (Vol Vo2) Total amplitude = 仝-a V i n2
ρ, which is the same as in Figures 7 and g.

この発明は、このような温度変化による検出感度の変化
を解消した回転磁界検出装置ｔ提案するのが目的である
。The purpose of the present invention is to propose a rotating magnetic field detection device t that eliminates such changes in detection sensitivity due to temperature changes.

ロ６発明の構成 ロー１．　問題点を解決するための手段この発明の回転
磁界検出装置は、角度をずらして配置した二つの磁気抵
抗素子の各一端を共通電位に接続し、各他端をそれぞれ
独立した定電流源に接続するとともに、二つの磁気抵抗
素子の前記他端の電圧差金検出することを特徴とするも
のである。B6 Structure of the invention Row1. Means for Solving the Problems The rotating magnetic field detection device of the present invention connects one end of each of two magnetoresistive elements arranged at different angles to a common potential, and connects each other end to an independent constant current source. In addition, the present invention is characterized in that a voltage difference between the other ends of the two magnetoresistive elements is detected.

又、この発明の回転磁界検出装置の第２の発明は磁気抵
抗素子と、この磁気抵抗素子と同じ抵抗温度係数を有す
る抵抗体の各一端を共通電位に接続し、各他端をそれぞ
れ独立した定電流源に接続するとともに、前記磁気抵抗
素子と抵抗体の前記他端の電圧差を検出することを特徴
とするものである。Further, the second invention of the rotating magnetic field detection device of the present invention is that one end of a magnetoresistive element and a resistor having the same resistance temperature coefficient as the magnetoresistive element are connected to a common potential, and the other ends are connected to each other independently. It is characterized in that it is connected to a constant current source and detects a voltage difference between the magnetoresistive element and the other end of the resistor.

ロー２０作　用 第１図において、二つの磁気抵抗素子（ＭＨＩ）、（Ｍ
Ｂ２）の抵抗１直Ｒ１（θ）、Ｒ２（θ〕は、磁界ノ角
度θと温度ｔの関数で、抵抗温度係数上α、温度ｔが零
のときの抵抗値’ｔ／ｌ’ｌ、Ｒ２とテると、で近似さ
れる。In Figure 1, two magnetoresistive elements (MHI), (M
B2) resistance 1 R1 (θ), R2 (θ) is a function of the magnetic field angle θ and temperature t, the resistance temperature coefficient is α, the resistance value 't/l'l when the temperature t is zero, When compared with R2, it is approximated by

なお、磁気抵抗素子（ＭＨＩ）、（ＭＢ２）と磁界の方
向θとの関係は第４図に従っており、υ１、Δρ２はそ
れぞれ、磁気抵抗素子（ＭＨＩ）、（ＭＢ２）について
、ジグザグパターンの長手方向に対し磁界の向きが平行
のときの電気抵抗ρ１１’から直角のときの電気抵抗ρ
よに引いた随である。The relationship between the magnetoresistive elements (MHI) and (MB2) and the magnetic field direction θ is according to Fig. 4, and υ1 and Δρ2 are the longitudinal direction of the zigzag pattern for the magnetoresistive elements (MHI) and (MB2), respectively. Electrical resistance ρ11' when the direction of the magnetic field is parallel to ρ11' when the direction of the magnetic field is perpendicular to
This is a very close follow-up.

素子（ＭＨＩ）、（ＭＢ２）にそれぞれ流ｎる定電流を
ＩＩ、　］：２とすると、各素子の電圧降下Ｖｏｌ、Ｖ
、２はＶＯ１＝Ｒ１（０）・工１　　　　　　　　　・
・・（７）ｖ０２！　＝Ｒ２（θ）　　・　工　２　　
　　　　　　　　　　　　　　　　　−　　−　　−　
　（８）となる。If the constant currents flowing through the elements (MHI) and (MB2) are II, ]:2, the voltage drops of each element Vol, V
, 2 is VO1=R1(0)・Eng.1・
...(7)v02! =R2(θ) ・Eng 2
− − −
(8) becomes.

画素子（ＭＨＩ）　、（ＭＢ２）　　はジグザグパター
ンが同じでθ＝４５°における電気抵抗は殆ど同じであ
るから、 Ｒ１（／＋αｔ）ζＲ２（／十αｔ） である。Since the pixel elements (MHI) and (MB2) have the same zigzag pattern and almost the same electrical resistance at θ=45°, R1(/+αt)ζR2(/10αt).

素子（ＭＲｌ）、（ＭＢ２−）に流す電流■１、工２は
°θ＝４５゜における画素子の電圧降下ＶＧＩ（θ＝４
５°）とＶｏ２（・０−４５°）とが等しくなるように
予めａ整・しておく。The currents 1 and 2 flowing through the elements (MRl) and (MB2-) are the voltage drop VGI (θ=4) of the pixel element at °θ=45°.
5°) and Vo2 (.0-45°) are adjusted in advance so that they are equal.

従って、画素子の前記他端の電圧差は、Ｖ　ｏ　１−Ｖ
ｏ　２＝Ｒ１（θ）　・ＩＮ−Ｒ２（（７）−工２＝ρ
１（／＋αｔ）Ｉｌ−Ｒ２（／＋αｔ）Ｉ２−）−−ｃ
ｏｓ２θ（△ρ１工１＋△ρ２■２）・・（９）であり
、しかも Ｒ１（／＋αｔ）工ｘ＝ρ２（／±αｔ）工２であるか
ら、 Ｖｏｌ−ＶＯ２＝−ｃｏｓ２Ｌ（、ＪＩＩＩ−１−Ａｐ
２Ｉ２）　　・−ＱＱとなる。Therefore, the voltage difference at the other end of the pixel element is V o 1-V
o 2=R1(θ) ・IN-R2((7)-Eng.2=ρ
1(/+αt)Il−R2(/+αt)I2−)−−c
Since os2θ (△ρ1 k1+△ρ2■2)...(9) and R1(/+αt)kx=ρ2(/±αt)k2, Vol-VO2=-cos2L(, JIII- 1-Ap
2I2) ・-QQ.

この式には抵抗値の温度変化分は含まれていないため、
温度ｔが変化しても、角度θに応じて変化する検出電圧
Ｖｏｌ−Ｖｏ２は変化しない。This formula does not include the temperature change in resistance value, so
Even if the temperature t changes, the detection voltage Vol-Vo2, which changes according to the angle θ, does not change.

なお、第２の発明の場合は一万の素子（ＭＢ２）の電圧
降下Ｖｏ２が、磁界め角度θによって変化しないため、 Ｖ　ｏ　１−Ｖ　ｏ　２＝−ｃ　ｏ　８２θ・Δρ］工
１となるが、温度による変化分を含んでいないことは第
１の発明と同じである。In the case of the second invention, the voltage drop Vo2 of the 10,000 elements (MB2) does not change depending on the magnetic field angle θ, so Vo 1 - Vo 2 = -co 82θ・Δρ] However, as in the first invention, it does not include changes due to temperature.

ロー８．実　　施　　例 二つの磁気抵抗素子（ＭＨＩ）と（ＭＢ２）は第２図に
示すように基板（４）の表面に形成されたジグザグパタ
ーンとして構成され、一方の素子のジグザグパターンの
長手方向（つまり素子を流れる主電流の方向）は他方の
素子のジグザグパターンの長平方向と直角に配置されて
いる。　（５）は回転軸で上端には直径方向に着磁した
環状磁石（６）が固層されていて、軸（５）の回転につ
れ基板（４）の面内で回転する磁界が生じ、この回転磁
界の角度に応じて素子（ＭＨＩ　）、（ＭＢ２）の電気
抵抗が変化する。　磁界の角度θと電気抵抗との関係は
第４図に基いて説明した従来技術の場合と同じで、温度
ｔと角度θの関数として、前記（５）式、（６）式であ
られされる。Row 8. Example Two magnetoresistive elements (MHI) and (MB2) are configured as a zigzag pattern formed on the surface of a substrate (4) as shown in FIG. The direction of the main current flowing through the element is arranged perpendicular to the long plane direction of the zigzag pattern of the other element. (5) is a rotating shaft, and a ring magnet (6) magnetized in the diametrical direction is solidly layered at the upper end. As the shaft (5) rotates, a magnetic field is generated that rotates within the plane of the substrate (4). The electrical resistance of the elements (MHI) and (MB2) changes depending on the angle of the rotating magnetic field. The relationship between the angle θ of the magnetic field and the electrical resistance is the same as in the case of the prior art explained based on FIG. .

磁気抵抗素子（ＭＲＩ）、（ＭＲ２）を第１図のように
、一端を共通端子の接地（ＧＮＤ）に接続し、各他端に
定電流源（７）、（８）ヲそれぞれ接続し、定電施工１
、工２を流す。　　ＩＩと工２は各素子の電圧降下がθ
＝４５゜のときに等しくなるように定める。As shown in Fig. 1, one end of the magnetoresistive element (MRI) (MR2) is connected to the ground (GND) of the common terminal, and the constant current sources (7) and (8) are connected to the other end, respectively. Constant voltage construction 1
, process 2. For II and Step 2, the voltage drop of each element is θ
= 45° so that they are equal.

そうすると前記（７）式と（８）式が成立する。　従っ
て画素子の端子電圧の差Ｖｏｌ　−Ｖｏ２　ｆ検出する
と、前記可成に示すように Ｖｏｌ−ＶＯ２＝−００Ｂ２ｆ）・（Δρ１１１＋Δρ
２Ｉ２　）となり温度に無関係となる。　電圧の差は比
較器（３）で検出する。　定電流源（７）と（８）には
図示されてない電源から電圧Ｖ４１供給する。Then, the above equations (7) and (8) hold true. Therefore, when the difference between the terminal voltages of the pixel elements Vol - Vo2 f is detected, Vol - VO2 = -00B2f) / (Δρ111 + Δρ
2I2) and is independent of temperature. The voltage difference is detected by a comparator (3). A voltage V41 is supplied to the constant current sources (7) and (8) from a power source (not shown).

第３図（ＡＸＢ）は、素子（ＭＨＩ）、（ＭＲ２）の端
子電圧ＶＯＩとＶｏ２　ｆ示し、角度（θ）に応じて変
化する様子が示されている。　実線に示す状態から温度
が上昇すると破線の状態に変り、中心値が上昇するが、
変動分つまり振幅は変らず Ｖ１ｍ＝Ｖ１ｍ’　　、　　　Ｖ２ｍ＝Ｖ２ｍ’である
。　なお、ＶｌｍとＶ２ｍ　ｌｄ温曳上昇前の変動分の
全振幅全、Ｖ１ｍ’とＶ２ｍ’は温度上昇後の全振幅を
あられ丁。FIG. 3 (AXB) shows the terminal voltages VOI and Vo2f of the elements (MHI) and (MR2), and how they change depending on the angle (θ). When the temperature rises from the state shown by the solid line, it changes to the state shown by the broken line, and the central value increases, but
The fluctuation amount, that is, the amplitude does not change, and V1m=V1m' and V2m=V2m'. In addition, Vlm and V2m ld are the total amplitudes of fluctuations before the temperature rise, and V1m' and V2m' are the total amplitudes after the temperature rise.

第弘図は第１因に比して、磁気抵抗素子と定電流源の位
置全通にした実施例であるが、その作用効果は第１図と
同じである。Compared to the first factor, Fig. 1 is an embodiment in which the magnetoresistive element and the constant current source are placed all the way through, but the effect is the same as that in Fig. 1.

第Ｓ図の実施例は第１図と比較して、磁気抵抗素子（Ｍ
Ｒ２）の代りに固定抵抗（Ｒ２）ｔ−設けたもので、固
定抵抗（Ｒ２）の抵抗＠全磁気抵抗素子（ＭＨＩ）の抵
抗値とほぼ同じに定め、かつθ＝４５°における素子（
ＭＨＩ）の電圧降下と、固定抵抗（Ｒ２）の電圧降下が
等しくなるように定電流源（７）と（８）の電流１１゜
Ｉ、４−Ａｆ！Ｉ整ｊ６゜ このようにすると、磁界の角度θの変化に応じて正弦波
状に変化する差電圧Ｖｏｌ　−Ｖｏ２は第１図と第ｑ図
の実施例に比しその変動分は半分になるが、温度の影響
を受けない点は同じである。In comparison with FIG. 1, the embodiment shown in FIG.
A fixed resistor (R2) is provided instead of R2), and the resistance of the fixed resistor (R2) is set to be almost the same as the resistance value of the total magnetoresistive element (MHI), and the element at θ = 45° (
The currents 11°I, 4-Af! of the constant current sources (7) and (8) are adjusted so that the voltage drop across MHI) and the voltage drop across the fixed resistor (R2) are equal. By doing this, the difference voltage Vol - Vo2, which changes sinusoidally in response to changes in the angle θ of the magnetic field, will have half the variation compared to the embodiments shown in Figures 1 and q. , are the same in that they are not affected by temperature.

第１図、第グ図、第Ｓ図の実施例で、素子（ＭＨＩ入（
ＭＲ２）　、抵抗（Ｒ２）に印加する電圧はほぼ電源電
圧近くまでとれるので、そのｉ＋＆　ｆ　Ｖｉｎとする
と、ＶＯＩ　−ＶＯ２の変動分の全振幅は、第１図と第
グ図の実施例では、 となり、前記従来例の約ｑ倍となる。　ただし、実施例
である第５図では変動分の全振幅がＡ／’、ｙ　１ｎρ となり、従来例の約２倍となる。In the embodiments shown in Fig. 1, Fig. 1, and Fig.
MR2), the voltage applied to the resistor (R2) can be taken almost close to the power supply voltage, so if i + & f Vin, the total amplitude of the fluctuation of VOI - VO2 is as follows in the embodiments shown in Figs. This is approximately q times that of the conventional example. However, in FIG. 5, which is an embodiment, the total amplitude of the variation is A/', y 1nρ, which is about twice that of the conventional example.

ハ１発明の効果 この発明では、磁気抵抗素子に定電流を流すようにした
ため、温度が変化しても流れる電流が変らない。　従っ
て磁界の角度θに応じて変化する差電圧の変動分が湿度
の影響全受けなくなる効果がある。　又、限られた電源
電圧で用いる場合に、素子当りの印加電圧が大きくでき
、それだけ検出感度を向上できる効果がある。C1 Effects of the Invention In the present invention, since a constant current is caused to flow through the magnetoresistive element, the flowing current does not change even if the temperature changes. Therefore, there is an effect that the variation of the differential voltage that changes depending on the angle θ of the magnetic field is completely unaffected by humidity. Furthermore, when used with a limited power supply voltage, the applied voltage per element can be increased, which has the effect of improving detection sensitivity accordingly.

【図面の簡単な説明】[Brief explanation of drawings]

第１図はこの発明の実施例の電気回路、第２図は回転磁
石と磁気抵抗素子との関係？説明する斜面図、第３図（
４）、ω）は第１図の回路の電圧と磁界の角度θとの関
係を示す線図、第グ図は他の実施例の電気回路、第Ｓ図
は更に他の実施例の電気回路、第６図は磁気抵抗素子と
磁界との関係全説明する図、第７図は従来技術の出力電
圧を説明する図、第５図と第り図は従来技術の電気回路
、第７０図（４）、艶）は第り図の電圧を説明する図で
ある。 （ＭＨＩ）、（ＭＲ２）・・・磁気抵抗素子（ＧＮＤ　
）・・・接地（共通電位） （７）、＜ｇ＞　・・・定電流源 （３）・・・比較器Fig. 1 shows an electric circuit of an embodiment of the invention, and Fig. 2 shows the relationship between the rotating magnet and the magnetoresistive element. Slope diagram to explain, Figure 3 (
4), ω) are diagrams showing the relationship between the voltage of the circuit in Figure 1 and the angle θ of the magnetic field, Figure G is an electric circuit of another embodiment, and Figure S is an electric circuit of still another embodiment. , FIG. 6 is a diagram completely explaining the relationship between the magnetoresistive element and the magnetic field, FIG. 7 is a diagram explaining the output voltage of the prior art, FIG. 5 and FIG. 4), Gloss) is a diagram explaining the voltage in the diagram. (MHI), (MR2)... Magnetoresistive element (GND
)...Ground (common potential) (7), <g>...Constant current source (3)...Comparator

Claims (1)

【特許請求の範囲】 〔１〕角度をずらして配置した二つの磁気抵抗素子の各
一端を共通電位に接続し、各他端をそれぞれ独立した定
電流源に接続するとともに、二つの磁気抵抗素子の前記
他端の電圧差を検出することを特徴とする回転磁界検出
装置。 〔２〕磁気抵抗素子と、この磁気抵抗素子と同じ抵抗温
度係数を有する抵抗体の各一端を共通電位に接続し、各
他端をそれぞれ独立した定電流源に接続するとともに、
前記磁気抵抗素子と抵抗体の前記他端の電圧差を検出す
ることを特徴とする回転磁界検出装置。[Scope of Claims] [1] One end of each of two magnetoresistive elements arranged at different angles is connected to a common potential, each other end is connected to an independent constant current source, and the two magnetoresistive elements A rotating magnetic field detection device for detecting a voltage difference between the other ends of the rotating magnetic field. [2] Connecting one end of a magnetoresistive element and a resistor having the same temperature coefficient of resistance as the magnetoresistive element to a common potential, and connecting each other end to an independent constant current source,
A rotating magnetic field detection device that detects a voltage difference between the magnetoresistive element and the other end of the resistor.