WO2011141969A1 - 磁界角計測装置およびこれを用いた回転角計測装置 - Google Patents
磁界角計測装置およびこれを用いた回転角計測装置 Download PDFInfo
- Publication number
- WO2011141969A1 WO2011141969A1 PCT/JP2010/003267 JP2010003267W WO2011141969A1 WO 2011141969 A1 WO2011141969 A1 WO 2011141969A1 JP 2010003267 W JP2010003267 W JP 2010003267W WO 2011141969 A1 WO2011141969 A1 WO 2011141969A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- magnetic field
- current
- field angle
- voltage
- tmr element
- Prior art date
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/06—Sense amplifiers; Associated circuits, e.g. timing or triggering circuits
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N50/00—Galvanomagnetic devices
- H10N50/10—Magnetoresistive devices
Definitions
- the present invention relates to a magnetic field angle measurement device configured using a tunnel magnetoresistive element (TMR element) having a fixed magnetization layer, and a rotation angle measurement device using the same.
- TMR element tunnel magnetoresistive element
- a magnetic angle measurement device that measures the direction of a magnetic field (magnetic field angle)
- a rotation angle measurement device that measures the rotation angle of a rotating body by measuring the magnetic field angle of a magnet attached to the rotating body
- the sensor element to be detected influences the measurement characteristics.
- magnetic field angle measuring devices and rotational angle measuring devices those using a magnetoresistive element (MR element) have been known conventionally.
- an anisotropic magnetoresistive element As an MR element, an anisotropic magnetoresistive element (AMR element), a giant magnetoresistive element (GMR element), a tunnel magnetoresistive element (TMR element), etc. are known. In any of these, the resistance value of the element changes as the external magnetic field direction (magnetic field angle) or the intensity changes.
- the S / N ratio (signal / noise ratio) is an important index as the measurement performance of the magnetic field angle measurement apparatus.
- the S / N ratio of the MR element is governed by the change amount of the element resistance with respect to the change of the magnetic field angle, and the S / N ratio improves as the change rate of the element resistance value with respect to the constant magnetic field angle change increases.
- the maximum rate of change in resistance due to magnetic field angle change is called MR ratio, and is about 2% for AMR elements and about 10% for GMR elements, but reaches 50% or more for TMR elements.
- TMR elements have recently come to have MR ratios exceeding 100% due to improvement of the tunnel insulating layer used for the elements, etc., and TMR elements reaching 600% have also been reported.
- the present invention relates to a magnetic field angle measurement apparatus and a rotation angle measurement apparatus using a TMR element, and more particularly to a magnetic field angle measurement apparatus using a TMR element having a high MR ratio and a rotation angle measurement apparatus using the same.
- the GMR element there is a granular type GMR element in which particles of ferromagnetic material having a diameter of about 5 nm are dispersed in an insulator.
- the direction of the magnetic field in the ferromagnetic particles also changes, and the resistance of the film changes. Since the action of granular GMR elements is caused by tunneling between particles, it may be regarded as a tunnel magnetoresistive element, but the MR ratio remains at about 10%.
- the granular type GMR element is an element not having a fixed magnetization layer, and is not targeted in the present invention.
- FIG. 21 shows the structure of a TMR element having a fixed magnetization layer.
- the TMR element 51 has a laminated structure in which the tunnel insulating layer 12 is sandwiched between the pinned magnetization layer 13 and the free magnetization layer 11.
- the fixed magnetization layer 13 and the free magnetization layer 11 are made of, for example, a magnetic material containing Co, Fe, Ni or the like as a component.
- the tunnel insulating layer 12 is made of an insulator such as aluminum oxide (Al 2 O 3 ) or magnesium oxide (MgO) and has a film thickness of about 0.5 to 2 nm.
- the magnetization direction 22 in the fixed magnetization layer 13 is fixed in a predetermined direction at an angle ⁇ p and does not change by the external magnetic field 30.
- the magnetization direction 20 in the free magnetization layer 11 changes at an angle ⁇ f in accordance with the angle ⁇ m of the external magnetic field direction 30.
- R (AP) is obtained in the case of anti-parallel at °.
- the MR ratio (MR) of the TMR element is defined by the following equation.
- the rotating body to be measured is provided with a rotating magnetic body in which the N pole and the S pole of the magnet are alternately arranged, and the magnetic field direction reversed with the rotation of the rotating body is TMR element.
- the TMR element is used as a magnetic encoder in a bridge configuration.
- FIG. 22 shows a bridge configuration 60 consisting of four TMR elements. Magnets are arranged at a ⁇ pitch on the rotating body that is to be detected in the rotational state.
- the present invention has been made to solve the above-mentioned problems, and according to the present invention, a magnetic field angle measurement device capable of highly accurate magnetic field angle measurement even if a TMR element having a high MR ratio is used, Provided is a rotation angle measuring device capable of measuring a rotation angle with high accuracy using the same.
- the present invention relates to a magnetic field angle measurement device having a magnetic sensor and a magnetic field angle detection circuit, wherein the magnetic sensor has a TMR element having a fixed magnetization layer, and the magnetic field angle detection circuit serves as a bias voltage for the TMR element of the magnetic sensor.
- the power supply unit may output a constant voltage, and a current detection unit may detect a current flowing through the TMR element.
- the input impedance of the current detection unit may be zero.
- the current detection unit has an OP amplifier for detecting the conduction current of the TMR element, and the input impedance of the current detection unit is made zero by virtually grounding the input terminal of the OP amplifier. It is characterized by having done.
- the power supply unit is characterized by outputting a constant voltage composed of a pulse voltage as a bias voltage to the TMR element of the magnetic sensor.
- the magnetic sensor is characterized by having two TMR elements in which the magnetization directions of the fixed magnetization layer are different by 90 ° from each other.
- the TMR element of the magnetic sensor has a first feed terminal, a second feed terminal, and a first sense terminal, and the magnetic field angle detection circuit serves as a bias voltage for the TMR element of the magnetic sensor.
- the power supply unit for outputting a constant voltage and a current detection unit for detecting the output current of the TMR element, wherein the terminal voltage of the TMR element is detected by the first sense terminal, and the power supply unit determines the terminal voltage Feedback control to match the voltage value of V.
- the TMR element has a second sense terminal in addition to the first sense terminal, and the terminal voltage of the TMR element is detected by the first sense terminal and the second sense terminal. It is characterized by
- the power supply unit includes a differential amplifier differentially receiving an output voltage of the first sense terminal and an output of a reference voltage generation unit.
- the power supply unit In the magnetic field angle measurement device, the power supply unit generates a pulse voltage.
- the magnetic sensor is characterized by having two TMR elements in which the magnetization directions of the fixed magnetization layer are different by 90 ° from each other.
- the magnetic sensor has a TMR element having a fixed magnetization layer
- the magnetic field angle detection circuit includes a current supply unit and an output current of the TMR element.
- a current detection unit for detecting a current and the current supply unit outputs a current to a voltage input terminal connected to a voltage generation unit, a current input terminal for inputting a current from the current detection unit, and the magnetic sensor
- the current flowing through the current input terminal is equal to the current flowing through the current output terminal, and the voltage of the current output terminal is set based on the voltage of the voltage generation unit, and
- the current detection unit is connected to a current input terminal, and the magnetic sensor is connected to a current output terminal.
- the current supply unit includes a field effect transistor and a current supply unit OP amplifier, and one terminal of the field effect transistor is provided at an input terminal of the current supply unit OP amplifier A voltage generation unit is connected.
- the current supply unit includes a transistor in which an output voltage of the voltage generation unit is input to a base.
- the voltage generation unit generates a pulse voltage.
- the magnetic sensor is characterized by having two TMR elements in which the magnetization directions of the fixed magnetization layer are different by 90 ° from each other.
- the magnetic field angle detection circuit includes two of the current supply units, and the current supply units are electrically connected to each of the two TMR elements.
- the present invention is characterized by a rotation angle measurement device including the above-described magnetic field angle measurement device and a magnet attached to a rotating body.
- the magnetic sensor has the TMR element having the fixed magnetization layer
- the magnetic field angle detection circuit is the TMR element of the magnetic sensor
- the terminals of the magnetic sensor having the TMR element by setting the input impedance of the current detection unit to zero, and having a power supply unit for outputting a constant voltage as a bias voltage and a current detection unit for detecting the conduction current of the TMR element.
- a magnetic field angle measurement device capable of measuring a magnetic field angle with high accuracy even if the voltage can be kept constant and the TMR element having a high MR ratio is used.
- a rotation angle measurement device capable of measuring the rotation angle with high accuracy by using the magnetic field angle measurement device with high accuracy.
- Block diagram showing a motor control method of Embodiment 9 of the present invention Block diagram showing the configuration of Embodiment 10 of the present invention
- a circuit diagram showing a detailed circuit configuration of FIG. A circuit diagram showing a modification of FIG.
- the circuit diagram which shows the structure of Example 11 of this invention A schematic view showing the configuration of a conventional TMR element
- TMR element structure a TMR element having the structure described in FIG. 21 is used.
- MgO was used as a tunnel insulating layer.
- the MR ratio is as high as 100% or more.
- the MR ratio is further increased.
- Aluminum oxide (Al 2 O 3 ) can also be used as the tunnel insulating layer.
- T is a TMR coefficient
- ⁇ g represents a conductance change rate due to a magnetic field change
- ⁇ g is expressed by the following equation.
- Equation 3 it is not the resistance but the conductance that is proportional to cos ⁇ . It is theoretically shown that the magnetic field dependent term of the conductance is proportional to cos ⁇ .
- the MR ratio is as small as about 10% as in the GMR element, even if the magnetic field dependent term of the resistance is proportional to cos ⁇ , no significant error occurs even if the magnetic field dependent term of the conductance is treated as proportional to cos ⁇ .
- the MR ratio exceeds 50% as in the TMR element, a large error occurs when the magnetic field dependent term of the resistance is treated as being proportional to cos ⁇ .
- the resistance value of the TMR element 51a is R (P) as described above, TMR element Since the resistance value of 51c is R (AP), the voltage V1 of the signal terminal 61, that is, the element bias voltage V1 of the TMR element 51c is expressed by the following equation.
- FIG. 1 is a graph plotting V1 (0) and V1 (180 °) as a function of the MR ratio
- FIG. 2 is a plot of variation amount of element bias voltage V1 (0) ⁇ V1 (180 °) as a function of the MR ratio It is a graph.
- FIG. 3 is a graph showing an example of the relationship between the MR ratio of the TMR element and the bias voltage E (voltage applied E across the element). For example, as is known from the following document, the MR ratio changes largely with the bias voltage E.
- FIGS. 4A and 4B are schematic diagrams in which wave functions 11 and 22 including electron spins are added to the lower part of the upper electron energy band diagram.
- the two wave functions have spins in the same direction (FIG. 4A)
- the two wave functions combine to form an electron path between the pinned magnetic layer and the free magnetic layer, and a current flows.
- the spins of the two wavefunctions are different (FIG. 4B)
- the element bias voltage As the element bias voltage is increased, the contribution of the wave function of the excited state increases in addition to the wave function of the ground state. Since antiparallel spins do not necessarily cancel each other between wave functions in different excited states, current does not completely return to a high resistance state. Thus, as the device bias voltage increases, the MR ratio decreases because the resistance of R (AP) decreases. (Cause of deterioration of measurement accuracy) Based on the above points, the cause of the measurement accuracy deterioration in the magnetic field angle measurement device using the TMR element will be described. In the magnetic field angle measurement apparatus using the TMR element, the magnetic field angle ⁇ is obtained from the change in conductance (or change in resistance value) based on the relation of (Equation 3).
- FIG. 5 shows the configuration of a magnetic field angle measurement apparatus according to a first embodiment of the present invention.
- the magnetic field angle measurement device is constituted of a magnetic sensor 301 having a TMR element 51 and a magnetic field angle detection circuit 302.
- Reference numeral 71 denotes a first power supply terminal of the magnetic sensor 301
- reference numeral 72 denotes a second power supply terminal.
- the magnetic field angle detection circuit 302 includes a power supply unit 311 that supplies a constant voltage to the TMR element 51 and a current detection unit 321.
- the current detection unit 321 is configured by a current follower circuit (also referred to as a current-voltage conversion circuit) using an OP amplifier (operational amplifier) 323.
- the downward triangle means grounding to a common voltage.
- 324 is a feedback resistor, and 326 is a signal output terminal.
- the feature of the current detection unit 321 of the first embodiment is that the ground side terminal of the TMR element 51 is connected to the virtual ground terminal of the OP amplifier 323. Therefore, the ground terminal of the TMR element 51 is at the ground voltage regardless of the element current.
- the virtual ground terminal refers to a terminal having the same potential as the ground terminal.
- the reference voltage at virtual ground may be a constant voltage other than 0V.
- the ground voltage may be set in any way, it is set to 0 V in the first embodiment.
- the bias voltage of the TMR element 51 can be kept constant regardless of the magnitude of the element current by adopting such a circuit configuration. Therefore, since the MR ratio becomes constant, the conductance change rate defined by (Equation 4) also becomes constant, and the magnetic field angle can be determined accurately.
- the output signal voltage Vsig of the current detection unit 321 is ⁇ Id ⁇ Rd.
- the conductance of the TMR element 51 can be obtained as Id / E0, so the magnetic field angle ⁇ can be obtained by (Equation 3).
- impedance is zero means substantially zero impedance. That is, it does not have to be 0 in a strict sense, but may have a certain value of width.
- FIG. 6 shows another circuit configuration of the magnetic field angle detection circuit 302 in the first embodiment.
- the magnetic field angle detection circuit 302 includes a power supply unit 311 and a current detection unit 321.
- the power supply unit 311 includes a reference voltage generation unit 316 and generates a voltage Vb.
- the current detection unit 321 is composed of an OP amplifier 323 and a feedback resistor 324.
- the power supply terminal voltage of the magnetic sensor 301 and the output voltage of the power supply unit 311 are input to each input terminal of the OP amplifier 323.
- the terminal voltage of the magnetic sensor 301 becomes equal to the generated voltage Vb of the power supply unit 311 by the function of the OP amplifier 323. Further, the output signal voltage Vsig of the signal output terminal 326 of the current detection unit 321 is (Rd ⁇ i0 + Vb).
- Rd is the resistance value of the feedback resistor 324, and i 0 is the TMR element current of the magnetic sensor 301.
- the voltage across the terminals of the magnetic sensor 301 is kept constant at Vb regardless of the magnitude of the element current of the magnetic sensor 301 having a TMR element. Even when used, the magnetic field angle can be measured with high accuracy.
- the input terminal of the current detection unit 321 is virtually connected to the potential Vb by being connected to the input terminal of the OP amplifier 323. Thereby, the voltage between the terminals of the magnetic sensor 301 having a TMR element can be made constant.
- the third embodiment shows an example of a detection circuit using a pulse voltage power supply.
- a power supply unit that outputs a pulse voltage as shown in FIG. 7 is used.
- the current measurement value (zero point current) Iz at time t0 outputting 0 V and the current at time t1 outputting element bias voltage E0 The measurement value Idm is measured, and the difference between the two (Idm-Iz) is calculated. By doing this, it is possible to remove the drift and offset of the magnetic field angle detection circuit unit in real time, so that highly accurate measurement is possible.
- the circuit configuration in this case is shown in FIG. In FIG. 8, the power supply unit 311 in FIG. 5 is replaced with a power supply unit 311a.
- the magnetic field angle detection circuit 302 is provided with the power supply section 311a for outputting the pulse voltage shown in FIG. 7 and the voltage applied to the TMR element 51 is pulsed, the input power to the TMR element 51 is reduced and the heat generation of the element is suppressed. Therefore, drift of the device current can be reduced, and highly accurate and repeatable measurement results can be obtained. Furthermore, since the input power to the TMR element 51 is reduced, element deterioration hardly occurs, which is preferable in this respect as well.
- the pulse width is preferably 1 ⁇ s to 10 ms, and the pulse duty ratio, that is, (pulse width / pulse period) is preferably 0.01 to 0.5. Since the duty ratio of the pulse affects the average value of the input power to the TMR element, it is important to set it to an appropriate value.
- the pulse width is set to 100 ⁇ s
- the pulse cycle is set to 1 ms
- the duty ratio is set to 0.1.
- the detected current has no drift, and highly accurate angle measurement results can be obtained. Also in the circuit configuration of FIG. 9 of the fourth embodiment to be described next, the same effect can be obtained by pulsing the output voltage of the power supply unit 311.
- the element bias voltage of the TMR element 51 is as small as 1 V or less. Furthermore, as shown in FIG. 3, a higher MR ratio can be obtained as the bias voltage is smaller. Therefore, for the purpose of enhancing the S / N ratio of the magnetic field angle measurement, it is preferable to set the bias voltage small.
- the preferable bias voltage depends on the design of the TMR element, in particular, on the thickness of the tunnel insulating layer, but for example, about 0.1 to 0.3 V in the TMR element having the characteristics shown in FIG.
- the parasitic resistance means the tunnel junction portion of the TMR element 51 on the route from the power supply portion 311 ⁇ TMR element 51 ⁇ current detection portion 321 of the magnetic field angle detection circuit (the free magnetization layer 11 of FIG.
- the resistances other than the resistance of the fixed magnetization layer 13 including the following.
- the magnetic field angle measurement apparatus is constituted by the TMR element 51 and the magnetic field angle detection circuit 302.
- the TMR element 51 includes a first sense terminal 75 and a second sense terminal 76 in addition to the first feed terminal 71 and the second feed terminal 72.
- the power supply unit 311 of the magnetic field angle detection circuit 302 includes an input terminal for inputting the outputs of the first sense terminal 75 and the second sense terminal 76 in addition to the output terminal for outputting a voltage to the first power supply terminal 71.
- the voltage signal of the second sense terminal 76 is connected to the reference voltage generator 316.
- the reference voltage generation unit 316 generates a desired voltage value Vref and outputs the voltage superimposed on the input signal.
- the output of the reference voltage generator 316 and the signal input to the first sense terminal 75 are input to the differential amplifier 315, respectively.
- the output of the differential amplifier 315 is input to the power amplifier 317, and the output of the power amplifier 317 is output to the first power supply terminal 71 of the TMR element 51.
- the voltage amplification factor of the power amplifier is 1.
- the first sense terminal 75 is input to the input terminal of the differential amplifier 315, and the second sense terminal 76 is different via the reference voltage generation unit 316. It is connected to the input terminal of the dynamic amplifier 315. Since no current flows into the input terminal of the differential amplifier 315, no current flows in any sense terminal. Therefore, since the voltage drop due to the wiring or the like can be ignored, the voltage between the tunnel junctions of the TMR element 51 can be accurately detected.
- the second feed terminal 72 of the TMR element is connected to the current detector 321.
- the current detection unit 321 is configured by a circuit with zero input impedance as in the first embodiment.
- the voltage between the first sense terminal 75 and the second sense terminal 76 of the TMR element is fed back so as to be equal to the set voltage value Vref of the reference voltage generation unit 316 and a voltage is applied. Therefore, the bias voltage applied to the junction of TMR element 51 is maintained at Vref.
- FIG. 10 is a schematic view showing the wiring on the wafer 260 constituting the TMR element 51.
- the wafer pad 262a corresponding to the first power supply terminal 71 and the wafer pad 262c corresponding to the first sense terminal 75 have different wiring paths respectively. It is connected to the tunnel junction 252.
- the wafer pad 262 b corresponding to the second feed terminal 72 and the wafer pad 262 d corresponding to the second sense terminal 76 are connected to the tunnel junction 252 by different wiring paths.
- a bonding wire 265 connects the wafer pads 262a to 262d and the package terminals 261a to 261d.
- the wiring on the wafer of the TMR element 51 is separated.
- the wiring on the wafer is separated. It goes without saying that it is not necessary.
- FIG. 11 is a circuit in which the reference voltage generation unit 316 in FIG. 9 is replaced with a reference voltage generation unit 316a.
- a pulse voltage is generated by the reference voltage generator 316a.
- the power input to the TMR element 51 decreases in accordance with the duty ratio of the pulse, so the heat generation of the TMR element 51 is suppressed, the drift of the element current is reduced, and the measurement result with high accuracy and reproducibility. You can get Furthermore, since the input power to the TMR element 51 is reduced, element deterioration hardly occurs, which is preferable in this respect as well.
- the rotation angle measuring device is composed of a magnetic sensor 301 having a TMR element, a magnetic field angle detection circuit 302, and a magnet 202 provided on a rotating body 121 to be measured.
- the rotating body 121 rotates around the rotation shaft 226, the magnet 202 also rotates.
- the magnetic sensor 301 and the magnetic field angle detection circuit 302 used in the sixth embodiment have the same configuration as that shown in FIG.
- the TMR element in the magnetic sensor 301 is particularly preferable to arrange the TMR element in the magnetic sensor 301 at a position on the extension of the rotation axis of the rotating body. In this arrangement, since the magnetic field angle generated by the magnet 202 matches the rotation angle of the rotating body 121, the rotation angle of the rotating body 121 can be measured with high accuracy.
- the magnetic field strength generated by the magnet 202 is preferably such that the magnetic field strength at the installation location of the TMR element is 10 mT or more. With such a magnetic field strength, the TMR element operates in saturation with respect to the magnetic field. That is, all the spins in the free magnetization layer 11 align in the magnetic field direction. For this reason, even if the magnetic field intensity slightly changes due to the influence of the environmental temperature etc., the direction of the magnetic field can be correctly determined. Therefore, the rotation angle of the rotating body can be measured accurately.
- a ferrite magnet may be used, or a neodymium magnet or a samarium-cobalt magnet may be used.
- a neodymium magnet was used in this example.
- a seventh embodiment of the magnetic field angle measuring apparatus of the present invention will be described with reference to FIGS. 13 and 14.
- two TMR elements are used to measure the magnetic field angle in the entire angle range of 0 to 360 °.
- FIG. 13 is a block diagram showing the entire configuration of a rotation angle measurement apparatus including the magnetic field angle measurement apparatus of the seventh embodiment.
- the magnetic field angle measurement device is composed of a magnetic sensor 301 and a magnetic field angle detection circuit 302.
- FIG. 14 is a schematic view showing the arrangement of the TMR element package as the magnetic sensor 301.
- the angle ⁇ p of the magnetization direction 22 of the fixed magnetization layer of the TMR element wafer 260b is set to 90 ° while the angle of the magnetization direction 22 of the fixed magnetization layer of the TMR element wafer 260a is zero.
- each element is provided with a package terminal 261 corresponding to a first power supply terminal, a second power supply terminal, a first sense terminal, and a second sense terminal, and these are TMR element wafer 260a, It is connected to the wafer pad 262 of 260 b by a bonding wire 265.
- the element currents of TMR element 51a and TMR element 51b are respectively measured to obtain the conductance, and cos ⁇ and sin ⁇ can be obtained by removing the magnetic field independent term G0. Therefore, the magnetic field angle ⁇ is obtained by ArcTan conversion You can ask for it.
- the magnetic field angle detection circuit 302 includes a power supply unit 311A corresponding to the TMR element 51a, a current detection unit 321A, a power supply unit 311B corresponding to the TMR element 51b, and a current detection unit 321B. It has a portion 332.
- the configurations of the power supply unit 311A and the current detection unit 321A are the same as in FIG. That is, the power supply unit 311A is connected to each terminal of the TMR element 51a, and feeds back the applied voltage so that the bias voltage applied to the tunnel junction 252 of the TMR element 51a becomes a constant value. Then, the current detection unit 321A measures the element current Id (A) flowing through the TMR element 51a.
- the configurations of the power supply unit 311B and the current detection unit 321B are also the same as in FIG. Similarly, the current detection unit 321B measures the element current Id (B) flowing to the TMR element 51b.
- each device current is expressed by the following equation, as can be seen from (Equation 3) and (Equation 8).
- e0 is a reference voltage set in the reference voltage generation unit 316 in the power supply unit A 311A and the power supply unit B 311B.
- the bias voltage applied to the TMR elements 51A, 51B is equal to e0.
- the signal processing is simplified by setting the bias voltages applied to the TMR element 51A and the TMR element 51B to the same value e0.
- Signals corresponding to the values of the element currents Id (A) and Id (B) are input to the signal processing unit 331.
- the signal processing unit 331 calculates values obtained by subtracting the constant term e0G0 of (Equation 9) from the element current, and sets them as Id '(A) and Id' (B).
- the method of determining the value of the constant term e0G0 to be subtracted will be described later. In this way, as can be understood from (Equation 9), the magnetic field angle ⁇ can be obtained by the following equation by the ArcTan process (an arctangent process).
- atan 2 (y, x) ArcTan (y / x) + 180 °
- the magnetic field angle ⁇ can be obtained.
- Equation 9 a method of calculating the constant term e0G0 of (Equation 9) will be described.
- the rotating body is rotated at a constant speed, and the element currents Id (A) and Id (B) are sampled at several points in a period of N rotations (NN1). Accuracy will be improved if the number of sampling points is 100 or more. If the average value is determined for each of the sampled Id (A) value and Id (B) value, the second term becomes zero from the symmetry of cos ⁇ and sin ⁇ , and therefore the following equation is obtained.
- average (x) represents a process of obtaining an average value.
- the constant term e0G0 can be obtained.
- the obtained e0G0 value is stored in the parameter storage unit 332, and is used for the process of calculating Id '(A) from Id (A) described above.
- the coefficient e0T in equation (9) does not have to be determined for the following reason.
- the reason is that, since the atan 2 (y, x) processing of (Equation 10) is a processing for calculating the arctangent of the ratio like ArcTan (y / x), for example, the coefficients e0T mutually cancel each other.
- a rotation angle measurement apparatus using the magnetic field angle measurement device of the seventh embodiment will be described with reference to FIG. 13 again.
- the magnetic sensor 301 is preferably disposed on the extension of the rotation shaft 226 of the rotating body 121. In this arrangement, the angle of the magnetic field generated by the magnet 202 coincides with the actual rotation angle, so that the rotation angle of the rotating body can be measured with high accuracy.
- the magnetic field strength generated by the magnet 202 is preferably set so that the magnetic field strength at the installation location of the magnetic sensor 301 formed of a TMR element is 10 mT or more.
- the TMR element operates in saturation with respect to the magnetic field. That is, all the spins in the free magnetization layer 11 align in the magnetic field direction. For this reason, even if the magnetic field intensity slightly changes due to the influence of the environmental temperature etc., the direction of the magnetic field can be correctly determined. Therefore, the rotation angle of the rotating body can be measured accurately.
- a ferrite magnet may be used, or a neodymium magnet or a samarium-cobalt magnet may be used.
- a neodymium magnet was used in this example.
- the magnetic sensor 301 of this configuration and the magnetic field angle detection circuit 302 make the magnetic field angle at the point of the magnetic sensor 301 highly accurate over the entire range of 0 to 360 °. It can measure. Therefore, by measuring the direction of the magnetic field generated by the magnet 202 installed on the rotating body 121, it is possible to measure the rotation angle of the rotating body 121 with high accuracy.
- the present embodiment is configured of a motor unit 100 and a rotation angle detection unit 200.
- the motor unit 100 generates a rotational torque by rotating the plurality of rotating magnetic poles by the magnetic action of the plurality of fixed magnetic poles and the plurality of rotating magnetic poles, and includes the stator 110 and the plurality constituting the plurality of fixed magnetic poles.
- the rotor 120 constitutes a rotating magnetic pole of the
- the stator 110 is composed of a stator core 111 and a stator coil 112.
- the rotor 120 is oppositely disposed on the inner circumferential side of the stator 110 via an air gap, and is rotatably supported.
- a three-phase AC surface magnet synchronous motor is used as the motor 100.
- the housing is composed of a first bracket 102 and a second bracket 103 provided at both axial ends of the cylindrical frame 101.
- a bearing 106 is provided in the hollow portion of the first bracket 101, and a bearing 107 is provided in the hollow portion of the second bracket 103. These bearings rotatably support the rotating shaft 121.
- a seal member (not shown) consisting of an O-ring annularly provided is provided between the frame 101 and the first bracket 102.
- the seal member is sandwiched and compressed in the axial direction and the radial direction by the frame 101 and the first bracket 102. Thereby, the space between the frame 101 and the first bracket 102 is sealed to waterproof the front side. Further, the seal member is also waterproofed between the frame 101 and the second bracket 103.
- the rotation angle detection unit 200 is configured of a magnetic field sensor module 201 that measures a magnetic field angle and a sensor magnet 202.
- the rotation angle detection unit 200 is installed in a space surrounded by the housing 203 and the second bracket 103.
- the sensor magnet 202 is installed on an axis that rotates in conjunction with the rotation axis 121.
- the rotation axis 121 changes the rotation position, the direction of the generated magnetic field changes accordingly.
- the rotation angle (rotational position) of the rotation shaft 121 can be measured.
- the magnetic field sensor module 201 When the magnetic field sensor module 201 is installed on the rotation axis 226 of the rotation axis 121, an error in the spatial distribution of the magnetic field generated by the sensor magnet 202 is reduced, which is a preferable arrangement.
- the sensor magnet 202 is a two-pole magnet magnetized with two poles or a multi-pole magnet magnetized with four or more poles.
- the magnetic field sensor module 201 includes the magnetic sensor and the magnetic field angle detection circuit unit shown in FIGS. 13 and 14 of the seventh embodiment, and the magnetic field angle detection circuit unit has a signal processing unit.
- the magnetic sensor changes its output signal according to the direction of the magnetic field.
- one having two TMR elements in which the angle ⁇ p of the magnetization vector 22 of the fixed magnetization layer is shifted by 90 ° from each other is used. .
- the magnetic field sensor module 201 is installed in the housing 203.
- the housing 203 is preferably made of a material such as aluminum or resin having a magnetic susceptibility of 0.1 or less so as not to affect the magnetic flux direction.
- Example 9 was made of aluminum.
- the magnetic field sensor module 201 may be fixed to the motor unit, and may of course be fixed to components other than the housing 203. If the rotation angle of the rotating shaft 121 changes and the direction of the sensor magnet 202 changes if fixed to the motor unit, the change in the magnetic field direction in the magnetic field sensor module 201 is detected to detect This is because the rotation angle can be detected.
- a sensor wire 208 is connected to the magnetic field sensor module 201.
- the sensor wiring 208 transmits the output signal of the magnetic field sensor 201.
- FIG. 16 shows a control system of the motor unit of the rotation angle measuring device according to the present embodiment.
- a signal from the magnetic field sensor module 201 is input to an electronic control unit (ECU) 411, and the ECU 411 transmits a control command to the drive unit 412.
- the drive unit 412 outputs an appropriate voltage waveform to the stator 110 of the motor unit 100 to control the rotation speed, the position of the rotation shaft, and the like of the rotor 121.
- the rotation angle of the rotor 121 can be measured with high accuracy in the configurations of FIGS. Therefore, high precision control can be performed by the drive unit 412. Thereby, a motor with good energy efficiency can be realized. Alternatively, it is possible to realize a highly accurate motor that responds accurately to the command angle (command angle).
- the magnetic field sensor module 201 may be configured of only the magnetic sensor 301, and the magnetic field angle detection circuit 302 may be configured in the ECU 411.
- the magnetic field angle measurement device includes a magnetic sensor 301 and a magnetic field angle detection circuit 302.
- the magnetic sensor 301 uses a TMR element package.
- the magnetic field angle detection circuit 302 includes a current supply unit 341, a voltage generation unit 346, and a current detection unit 321.
- the current supply unit 341 includes a current input terminal 343, a current output terminal 344, and a voltage input terminal 345.
- the current supply unit 341 is configured as follows. That is, current i2 output from current output terminal 344 is equal to current i1 input to current input terminal 343, and output voltage Vb of current output terminal 344 is set by voltage Vbin input to voltage input terminal 345. Ru.
- the output voltage Vb is “set” by the input voltage Vbin of the voltage input terminal means that the input value Vbin and the output value Vb have an unambiguous correspondence.
- the input voltage Vbin may be equal to the output voltage Vb, or a value proportional to the input voltage Vbin may be output as the output voltage Vb.
- the terminal of the magnetic sensor 301 is connected to the current output terminal 344 of the current supply unit 341.
- the current detection unit 321 is connected to the current input terminal 343.
- the voltage generator 346 is connected to the voltage input terminal 345.
- the voltage applied to the terminals of the magnetic sensor 301 that is, the TMR element package can be maintained at a constant value Vb, and the current i2 flowing through the magnetic sensor 301 becomes the current input terminal current i1 of the current supply unit 341. Since they are equal, they can be measured by the current detection unit 321. Therefore, the TMR element current can be measured while keeping the terminal voltage of the TMR element constant, so that the magnetic field angle can be measured with high accuracy even if the TMR element having a high MR ratio is used.
- FIG. 18 shows an example in which the current supply unit 341 is configured by an OP amplifier 351 and a field effect transistor (FET) 352.
- FET field effect transistor
- the voltage generation unit 346 is connected to the voltage input terminal 345.
- the current detection unit 321 is connected to the current input terminal 343, and the magnetic sensor 301 is connected to the current output terminal 344.
- the voltage of the current output terminal 344 becomes equal to Vb due to the function of the OP amplifier 351. Further, since the input impedance of the signal input terminal of the OP amplifier 351 can be regarded as infinite, the current input terminal current i1 and the current output terminal current i2 become equal. That is, it can be understood that the function of the current supply unit is satisfied.
- the current detection unit 321 is configured by a current follower circuit.
- the current i2 flowing through the magnetic sensor 301 can be measured.
- FIG. 19 shows another circuit of the current supply unit 341.
- the current supply portion 341a is realized using the transistor 348.
- the base of transistor 348 is connected to voltage input terminal 345, the emitter is connected to current output terminal 344, and the collector is connected to current input terminal 343.
- Vbe is a base-emitter voltage governed by the junction characteristics of the transistor and is a constant voltage of about 0.7V. Therefore, the terminal voltage of the current output terminal 344 is kept constant at Vb2, and the current i2 is equal to the conduction current i1 of the current input terminal 343.
- FIG. 19 Since Vbe changes somewhat due to a large temperature change or the like, the configuration of FIG. 19 is more efficient, but has the advantage that it can be configured with one transistor at low cost.
- the eleventh embodiment uses a current mirror circuit as the current detection unit 321 in the configuration of the magnetic field angle detection circuit 302 shown in FIG. 17 of the tenth embodiment.
- the current mirror circuit is a circuit in which the currents i1 and i3 at the two terminals are equal, and several configurations are known.
- the current supply unit 341 operates such that the current i2 of the magnetic sensor 301 is equal to the current i2. Therefore, the current i2 of the magnetic sensor 301 can be measured by measuring the current i3.
- the voltage applied to the magnetic sensor 301 is maintained at a constant value Vb by the function of the current supply unit 341. Therefore, even when using the magnetic sensor 301 using a TMR element having a high MR ratio, the magnetic field angle is highly accurate. Can be measured.
- the magnetic field angle measuring apparatus has been described in the tenth and eleventh embodiments, the magnetic field angle measuring apparatus of the tenth and eleventh embodiments is installed on the rotating body 121 in the same manner as shown in FIGS. 12 and 13.
- the magnet 202 By combining with the magnet 202, it is possible to realize a rotation angle measuring device that measures the rotation angle of the rotating body 121 with high accuracy.
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Measuring Magnetic Variables (AREA)
- Hall/Mr Elements (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Description
(TMR素子構造)
実施例1においては、図21で説明した構造を持つTMR素子を用いる。実施例1ではトンネル絶縁層としてMgOを用いた。トンネル絶縁層12としてMgOを用いるとMR比が100%以上と高くなる。さらに単結晶のMgOを用いるとMR比は更に高くなる。トンネル絶縁層として酸化アルミ(Al2O3)を用いることもできる。
(磁界角計測装置の測定精度)
ここで、特にMR比が大きいTMR素子を用いた磁界角計測装置で測定精度が劣化していた理由を説明する。図22のブリッジ構成60における、TMR素子51cの両端電圧(以下素子バイアス電圧と呼ぶ)について、外部磁界角度θが0の場合、前述の通りTMR素子51aの抵抗値はR(P)、TMR素子51cの抵抗値はR(AP)であるから、信号端子61の電圧V1、すなわちTMR素子51cの素子バイアス電圧V1は、次式で表される。
(MR比のバイアス電圧依存性)
図3はTMR素子のMR比とバイアス電圧E(素子両端印加電圧E)との関係の一例を示すグラフである。例えば下記文献により知られている様に、MR比はバイアス電圧Eで大きく変化する。
"Japanese Journal of Applied Physics, Vol. 44, No. 19, 2005, pp. L 587-L 589"
MR比がバイアス電圧に依存して変化するのはTMR素子の特徴であり、これは次の理由による。TMR素子における固定磁性層と自由磁性層間の伝導現象は、それぞれの磁性層からトンネル絶縁層にしみ出した波動関数の相互作用に起因する。図4A、図4Bは上部の電子エネルギーバンド図に、電子のスピンを含めた波動関数Φ1、Φ2を下部に書き加えた模式図である。2つの波動関数が同一方向のスピンを持つ場合(図4A)は、2つの波動関数が結合し、固定磁性層と自由磁性層との間に電子の通り道が形成され電流が流れる。一方、2つの波動関数のスピンが異なる場合(図4B)は、波動関数が重なっても結合せず打ち消しあうため、電子が流れず高抵抗状態になる。
(測定精度の劣化原因)
以上の点を踏まえ、TMR素子を用いた磁界角計測装置での測定精度劣化の原因を説明する。TMR素子を用いた磁界角計測装置では、(数3)の関係を基にしてコンダクタンス変化(あるいは抵抗値変化)から磁界角度θを求める。しかしながら、磁界方向によりMR比が変化すると、(数5)に従ってコンダクタンス変化率βgも変化するので、(数3)のcosθの比例係数が変化する。このため、コンダクタンス変化量から磁界角度を算出しようとすると誤差が発生する。これが、測定精度劣化の一原因である。(数6)、(数7)からわかるように、この問題はMR比が高くなるほど顕著になる。
(本発明の磁界角計測装置)
図5に本発明による実施例1の磁界角計測装置の構成を示す。磁界角計測装置はTMR素子51を有する磁気センサ301と磁界角検出回路302で構成される。71は磁気センサ301の第1給電端子、72は第2給電端子である。
(a)磁界角検出回路302とTMR素子間の配線抵抗
(b)TMR素子パッケージ内の端子とウエハ上のパッドとのワイヤボンディング抵抗
(c)TMR素子が形成されたウエハ内のパッドとトンネル接合部の間の配線の配線抵抗
(d)電源部311の出力インピーダンス及び電流検出部321の入力インピーダンス
例えば、寄生抵抗が20Ωで素子電流が2mAで、バイアス電圧が0.1Vの場合、寄生抵抗による電圧降下は40mVであり、バイアス電圧の40%にも達する。すなわち、トンネル接合部に印加されるバイアス電圧は60mVに減少してしまう。したがって、図3の特性によりMR比が変化してしまうため、磁界角度計測に誤差が発生する。本実施例の磁界角計測装置は、このような課題を含めて解決するものである。
12・・・トンネル絶縁層
13・・・固定磁化層
51・・・TMR素子
71・・・第1給電端子
72・・・第2給電端子
75・・・第1センス端子
76・・・第2センス端子
121・・・回転体
200・・・回転角検出部
201・・・磁界角計測装置
202・・・磁石
226・・・回転軸
252・・・トンネル接合部
301・・・磁気センサ
302・・・磁界角検出回路
311・・・電源部
315・・・差動増幅器
316・・・基準電圧発生部
321・・・電流検出部
323・・・OPアンプ
326・・・信号出力端子
328・・・電流ミラー回路
341・・・電流供給部
343・・・電流入力端子
344・・・電流出力端子
345・・・電圧入力端子
346・・・電圧発生部
Claims (16)
- 磁気センサと磁界角検出回路を有する磁界角計測装置において、前記磁気センサは固定磁化層を有するTMR素子を有し、前記磁界角検出回路は前記磁気センサのTMR素子にバイアス電圧として定電圧を出力する電源部と、前記TMR素子の通電電流を検出する電流検出部を有し、前記電流検出部の入力インピーダンスをゼロとしたことを特徴とする磁界角計測装置。
- 請求項1に記載された磁界角計測装置において、前記電流検出部は前記TMR素子の通電電流を検出するOPアンプを有し、該OPアンプの入力端子を仮想接地することにより前記電流検出部の入力インピーダンスをゼロとしたことを特徴とする磁界角計測装置。
- 請求項1または2に記載された磁界角計測装置において、前記電源部は前記磁気センサのTMR素子にバイアス電圧としてパルス電圧からなる定電圧を出力することを特徴とする磁界角計測装置。
- 請求項1乃至3のいずれか1項に記載された磁界角計測装置において、前記磁気センサは、前記固定磁化層の磁化方向が互いに90°異なる2つのTMR素子を有することを特徴とする磁界角計測装置。
- 請求項1に記載された磁界角計測装置において、前記磁気センサのTMR素子は、第1給電端子と第2給電端子と第1センス端子を有し、前記磁界角検出回路は前記磁気センサのTMR素子にバイアス電圧として定電圧を出力する電源部と前記TMR素子の出力電流を検出する電流検出部とを有し、前記第1センス端子により前記TMR素子の端子電圧を検出し、前記電源部は前記端子電圧が所定の電圧値と一致するようにフィードバック制御を行うことを特徴とする磁界角計測装置。
- 請求項5に記載された磁界角計測装置において、前記TMR素子は、前記第1センス端子に加えて第2センス端子を有し、前記第1センス端子及び第2センス端子により前記TMR素子の端子電圧を検出することを特徴とする磁界角計測装置。
- 請求項5に記載された磁界角計測装置において、前記電源部は、前記第1センス端子の出力電圧と、基準電圧発生部の出力とを差動入力した差動増幅器を有することを特徴とする磁界角計測装置。
- 請求項5乃至7のいずれか1項に記載された磁界角計測装置において、前記電源部は、パルス電圧を発生することを特徴とする磁界角計測装置。
- 請求項5乃至8のいずれか1項に記載された磁界角計測装置において、前記磁気センサは、前記固定磁化層の磁化方向が互いに90°異なる2つのTMR素子を有することを特徴とする磁界角計測装置。
- 磁気センサと磁界角検出回路を有する磁界角計測装置において、前記磁気センサは固定磁化層を有するTMR素子を有し、前記磁界角検出回路は、電流供給部と、前記TMR素子の出力電流を検出する電流検出部を有し、前記電流供給部は、電圧発生部に接続された電圧入力端子と、前記電流検出部からの電流を入力する電流入力端子と、前記磁気センサへ電流を出力する電流出力端子を有し、前記電流入力端子の通電電流と前記電流出力端子の通電電流が等しく、かつ前記電流出力端子の電圧が前記電圧発生部の電圧に基づき設定され、前記電流供給部の電流入力端子に前記電流検出部が接続され、電流出力端子に前記磁気センサが接続されたことを特徴とする磁界角計測装置。
- 請求項10に記載された磁界角計測装置において、前記電流供給部は、電界効果トランジスタと、電流供給部OPアンプを有し,前記電流供給部OPアンプの入力端子に,前記電界効果トランジスタの1つの端子と,前記電圧発生部とが接続されていることを特徴とする磁界角計測装置。
- 請求項10に記載された磁界角計測装置において、前記電流供給部は、ベースに前記電圧発生部の出力電圧を入力したトランジスタを有することを特徴とする磁界角計測装置。
- 請求項10乃至12のいずれか1項に記載された磁界角計測装置において、前記電圧発生部がパルス電圧を発生することを特徴とする磁界角計測装置。
- 請求項10乃至12のいずれか1項に記載された磁界角計測装置において、前記磁気センサは、前記固定磁化層の磁化方向が互いに90°異なる2つのTMR素子を有することを特徴とする磁界角計測装置。
- 請求項14に記載された磁界角計測装置において、前記磁界角検出回路は前記電流供給部を2つ有し、前記2つのTMR素子のそれぞれに前記電流供給部が電気的に接続されたことを特徴とする磁界角計測装置。
- 請求項1乃至15のいずれか1項に記載された磁界角計測装置と、回転体に取り付けられた磁石とを有することを特徴とする回転角計測装置。
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2012514611A JP5439595B2 (ja) | 2010-05-14 | 2010-05-14 | 磁界角計測装置およびこれを用いた回転角計測装置 |
DE112010005566.1T DE112010005566B4 (de) | 2010-05-14 | 2010-05-14 | Magnetfeldwinkel-Messvorrichtung und Drehwinkel-Messvorrichtung, die diese verwendet |
US13/697,690 US9506997B2 (en) | 2010-05-14 | 2010-05-14 | Magnetic-field-angle measurement apparatus and rotational-angle measurement apparatus using same |
PCT/JP2010/003267 WO2011141969A1 (ja) | 2010-05-14 | 2010-05-14 | 磁界角計測装置およびこれを用いた回転角計測装置 |
US13/697,690 US20130063135A1 (en) | 2010-05-14 | 2010-05-14 | Magnetic-field-angle measurement device and rotational-angle measurement apparatus using same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2010/003267 WO2011141969A1 (ja) | 2010-05-14 | 2010-05-14 | 磁界角計測装置およびこれを用いた回転角計測装置 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2011141969A1 true WO2011141969A1 (ja) | 2011-11-17 |
Family
ID=44914038
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2010/003267 WO2011141969A1 (ja) | 2010-05-14 | 2010-05-14 | 磁界角計測装置およびこれを用いた回転角計測装置 |
Country Status (4)
Country | Link |
---|---|
US (2) | US20130063135A1 (ja) |
JP (1) | JP5439595B2 (ja) |
DE (1) | DE112010005566B4 (ja) |
WO (1) | WO2011141969A1 (ja) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2014092526A (ja) * | 2012-11-07 | 2014-05-19 | Mitsubishi Electric Corp | 磁気検出装置 |
JP2014126538A (ja) * | 2012-12-27 | 2014-07-07 | Toflo Corporation Kk | 流量センサ及び流量制御装置 |
US9074866B2 (en) | 2011-06-30 | 2015-07-07 | Hitachi Automotive Systems, Ltd. | Rotational angle measurement apparatus, control apparatus, and rotation-machine system |
WO2017126397A1 (ja) * | 2016-01-22 | 2017-07-27 | コニカミノルタ株式会社 | 磁気センサー |
JP2020521979A (ja) * | 2017-06-02 | 2020-07-27 | コミサリヤ・ア・レネルジ・アトミク・エ・オ・エネルジ・アルテルナテイブ | トンネル磁気抵抗を有する磁気抵抗センサの低周波雑音を抑制するためのシステムおよび方法 |
CN112327213A (zh) * | 2020-10-19 | 2021-02-05 | 南京工程学院 | 一种电回转体性能检测系统及检测方法 |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2018151304A (ja) * | 2017-03-14 | 2018-09-27 | エイブリック株式会社 | 磁気センサ回路、検査方法、及び製造方法 |
DE102020114551A1 (de) | 2020-05-29 | 2021-12-02 | Infineon Technologies Ag | Magnetoresistiver Sensor und Fertigungsverfahren für einen magnetoresistiven Sensor |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH077196A (ja) * | 1992-12-29 | 1995-01-10 | Eastman Kodak Co | 磁界センサ及び磁界検知方法 |
JPH0870149A (ja) * | 1994-08-30 | 1996-03-12 | Mitsubishi Materials Corp | 磁気抵抗素子 |
JPH10293040A (ja) * | 1997-04-17 | 1998-11-04 | Toyota Motor Corp | 検出装置 |
JPH10341049A (ja) * | 1997-06-09 | 1998-12-22 | Yokogawa Electric Corp | 磁気センサ |
JPH1168192A (ja) * | 1997-08-18 | 1999-03-09 | Hitachi Ltd | 多重トンネル接合、トンネル磁気抵抗効果素子、磁気センサおよび磁気記録センサヘッド |
JP2000091664A (ja) * | 1998-09-08 | 2000-03-31 | Oki Electric Ind Co Ltd | 磁気デバイス |
JP2001281313A (ja) * | 2000-01-27 | 2001-10-10 | Hitachi Metals Ltd | 磁界センサー、それを用いた磁気式エンコーダー、及び磁気ヘッド |
JP2007064813A (ja) * | 2005-08-31 | 2007-03-15 | Mitsubishi Electric Corp | 磁界検出装置およびそれを調整する方法 |
JP2008522146A (ja) * | 2004-11-25 | 2008-06-26 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | 並列磁気センサーストリップを備えた磁気センサー |
JP2010044046A (ja) * | 2008-07-14 | 2010-02-25 | Tdk Corp | 角度検出装置、及び角度検出方法 |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4075671A (en) | 1976-11-24 | 1978-02-21 | International Business Machines Corporation | Automatic ac biasing of a magnetoresistive element |
JPH0335181A (ja) * | 1989-06-30 | 1991-02-15 | Sharp Corp | 超電導磁気抵抗効果による磁界測定方法 |
US5103353A (en) * | 1990-05-01 | 1992-04-07 | International Business Machines Corporation | Low noise amplifier with short circuit protection for signals from magnetoresistive element |
JP4104748B2 (ja) | 1998-10-12 | 2008-06-18 | 富士通株式会社 | 磁気センサ、磁気ヘッド及び磁気エンコーダ |
JP2001002311A (ja) | 1999-06-22 | 2001-01-09 | Konica Corp | 接着剤付与方法、接着剤付与装置及び製本装置 |
JP3839697B2 (ja) * | 2001-10-17 | 2006-11-01 | アルプス電気株式会社 | 回転角度センサ |
DE102006032266A1 (de) | 2006-07-12 | 2008-01-17 | Infineon Technologies Ag | Sensorbauelement |
US7848043B1 (en) * | 2006-08-17 | 2010-12-07 | Marvell International Ltd. | Circuits, systems, and methods for low noise biasing of magnetic-resistance sensors |
JP2009180608A (ja) * | 2008-01-30 | 2009-08-13 | U R D:Kk | Icチップ形電流センサ |
US8269491B2 (en) * | 2008-02-27 | 2012-09-18 | Allegro Microsystems, Inc. | DC offset removal for a magnetic field sensor |
US7973527B2 (en) * | 2008-07-31 | 2011-07-05 | Allegro Microsystems, Inc. | Electronic circuit configured to reset a magnetoresistance element |
JP5156671B2 (ja) | 2009-02-27 | 2013-03-06 | 株式会社日立製作所 | 磁界検出装置および計測装置 |
JP5263024B2 (ja) | 2009-06-18 | 2013-08-14 | 株式会社日立製作所 | 回転角検出装置および回転速度検出装置 |
JP2011047930A (ja) * | 2009-07-31 | 2011-03-10 | Tdk Corp | 磁気抵抗効果素子およびセンサ |
JP5096442B2 (ja) | 2009-11-17 | 2012-12-12 | 株式会社日立製作所 | 回転角計測装置,モータシステム及び電動パワーステアリング・システム |
JP5380425B2 (ja) | 2010-12-28 | 2014-01-08 | 日立オートモティブシステムズ株式会社 | 磁界角計測装置,回転角計測装置およびそれを用いた回転機,システム,車両および車両駆動装置 |
-
2010
- 2010-05-14 JP JP2012514611A patent/JP5439595B2/ja active Active
- 2010-05-14 US US13/697,690 patent/US20130063135A1/en active Granted
- 2010-05-14 WO PCT/JP2010/003267 patent/WO2011141969A1/ja active Application Filing
- 2010-05-14 DE DE112010005566.1T patent/DE112010005566B4/de active Active
- 2010-05-14 US US13/697,690 patent/US9506997B2/en active Active
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH077196A (ja) * | 1992-12-29 | 1995-01-10 | Eastman Kodak Co | 磁界センサ及び磁界検知方法 |
JPH0870149A (ja) * | 1994-08-30 | 1996-03-12 | Mitsubishi Materials Corp | 磁気抵抗素子 |
JPH10293040A (ja) * | 1997-04-17 | 1998-11-04 | Toyota Motor Corp | 検出装置 |
JPH10341049A (ja) * | 1997-06-09 | 1998-12-22 | Yokogawa Electric Corp | 磁気センサ |
JPH1168192A (ja) * | 1997-08-18 | 1999-03-09 | Hitachi Ltd | 多重トンネル接合、トンネル磁気抵抗効果素子、磁気センサおよび磁気記録センサヘッド |
JP2000091664A (ja) * | 1998-09-08 | 2000-03-31 | Oki Electric Ind Co Ltd | 磁気デバイス |
JP2001281313A (ja) * | 2000-01-27 | 2001-10-10 | Hitachi Metals Ltd | 磁界センサー、それを用いた磁気式エンコーダー、及び磁気ヘッド |
JP2008522146A (ja) * | 2004-11-25 | 2008-06-26 | コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ | 並列磁気センサーストリップを備えた磁気センサー |
JP2007064813A (ja) * | 2005-08-31 | 2007-03-15 | Mitsubishi Electric Corp | 磁界検出装置およびそれを調整する方法 |
JP2010044046A (ja) * | 2008-07-14 | 2010-02-25 | Tdk Corp | 角度検出装置、及び角度検出方法 |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9074866B2 (en) | 2011-06-30 | 2015-07-07 | Hitachi Automotive Systems, Ltd. | Rotational angle measurement apparatus, control apparatus, and rotation-machine system |
JP2014092526A (ja) * | 2012-11-07 | 2014-05-19 | Mitsubishi Electric Corp | 磁気検出装置 |
CN103809136A (zh) * | 2012-11-07 | 2014-05-21 | 三菱电机株式会社 | 磁性检测装置 |
JP2014126538A (ja) * | 2012-12-27 | 2014-07-07 | Toflo Corporation Kk | 流量センサ及び流量制御装置 |
WO2017126397A1 (ja) * | 2016-01-22 | 2017-07-27 | コニカミノルタ株式会社 | 磁気センサー |
JP2020521979A (ja) * | 2017-06-02 | 2020-07-27 | コミサリヤ・ア・レネルジ・アトミク・エ・オ・エネルジ・アルテルナテイブ | トンネル磁気抵抗を有する磁気抵抗センサの低周波雑音を抑制するためのシステムおよび方法 |
CN112327213A (zh) * | 2020-10-19 | 2021-02-05 | 南京工程学院 | 一种电回转体性能检测系统及检测方法 |
CN112327213B (zh) * | 2020-10-19 | 2024-04-19 | 南京工程学院 | 一种电回转体性能检测系统及检测方法 |
Also Published As
Publication number | Publication date |
---|---|
JP5439595B2 (ja) | 2014-03-12 |
US9506997B2 (en) | 2016-11-29 |
DE112010005566T5 (de) | 2013-03-14 |
JPWO2011141969A1 (ja) | 2013-07-22 |
DE112010005566B4 (de) | 2018-05-09 |
US20130063135A1 (en) | 2013-03-14 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2011141969A1 (ja) | 磁界角計測装置およびこれを用いた回転角計測装置 | |
CN107229024B (zh) | 磁场检测器 | |
JP5263024B2 (ja) | 回転角検出装置および回転速度検出装置 | |
US9007054B2 (en) | Angle sensor with misalignment detection and correction | |
US8193805B2 (en) | Magnetic sensor | |
US8487611B2 (en) | Magnetic sensor including a bridge circuit | |
US8896295B2 (en) | Magnetic field sensor having multiple sensing elements and a programmable misalignment adjustment device for misalignment detection and correction in current sensing and other applications | |
EP2790030B1 (en) | Magnetic field sensing device | |
US9638767B2 (en) | Current sensor and attachment structure of the same | |
US20120062215A1 (en) | Magnetic-balance-system current sensor | |
US20130265041A1 (en) | High accuracy differential current sensor for applications like ground fault interrupters | |
JP5705705B2 (ja) | 磁界角計測装置およびそれを用いた回転機 | |
US20060012459A1 (en) | Sensor and method for measuring a current of charged particles | |
JPWO2014181382A1 (ja) | 磁気電流センサおよび電流測定方法 | |
US20120126797A1 (en) | Magnetic position detection apparatus | |
WO2012053296A1 (ja) | 電流センサ | |
JP6460372B2 (ja) | 磁気センサ及びその製造方法、並びにそれを用いた計測機器 | |
JP6151544B2 (ja) | 磁気センサ装置およびロータリエンコーダ | |
Borole et al. | Design, fabrication, and characterization of giant magnetoresistance (GMR) based open-loop current sensor with U-shaped current carrying conductor | |
JP2012063203A (ja) | 磁気センサ | |
JP5161055B2 (ja) | 磁界検出装置 | |
JP2018044789A (ja) | 磁界検出装置 | |
JP5631378B2 (ja) | 磁界検出方法 | |
WO2013179613A1 (ja) | 電流センサ | |
WO2012042336A1 (ja) | 電力計測装置および電力計測方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 10851354 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2012514611 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 13697690 Country of ref document: US |
|
WWE | Wipo information: entry into national phase |
Ref document number: 112010005566 Country of ref document: DE Ref document number: 1120100055661 Country of ref document: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 10851354 Country of ref document: EP Kind code of ref document: A1 |