JP2010190571A - Magnetic detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detector which, especially, can generate a magnetic field detection signal for a the magnetic field intensity change of an external magnetic field more easily as compared to the conventional technique, and enables standardization of an integrated circuit. <P>SOLUTION: A first output waveform A is acquired from a first output extraction portion of a first series circuit, and a second output waveform B is acquired from a second extraction portion of a second series circuit. The first and second output waveforms A and B cross each other, when an external magnetic field H in the (+) direction has a first magnetic field intensity H1, and when an external magnetic field H in the (-) direction has a second magnetic field intensity H2 respectively, and the relation in magnitude between the output values of the first output waveform A and the second output waveform B when the magnetic field intensity is larger than the first and second magnetic field intensities H1 and H2 reverses when the magnetic field intensity is smaller than the first and second magnetic field intensities H1 and H2. Thereby, the magnetic field detection signal with respect to the magnetic field intensity change of the external magnetic field can be generated more easily as compared to the conventional technique. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic detection device including a magnetoresistive effect element, and more particularly, to a magnetic detection device that can easily generate a magnetic field detection signal as compared with the related art and can standardize an integrated circuit.

  It is possible to use a magnetic detection device (magnetic sensor) using a magnetoresistive effect element for opening / closing detection of an electronic device such as a folding cellular phone or an electrical appliance such as a refrigerator.

  Since the magnetoresistive effect element changes its electric resistance value with respect to the magnetic field strength of the external magnetic field, it is possible to detect the strength of the magnetic field strength of the external magnetic field that enters the magnetic detection device by a voltage change based on the resistance change. is there.

The magnetic detection device is connected to the resistance element portion including a magnetoresistive effect element and a fixed resistance element, and generates and outputs an on signal or an off signal (magnetic field detection signal) based on the voltage change. And an integrated circuit (IC).
Japanese Patent Laid-Open No. 10-82895 JP 2004-198186 A Japanese Patent Application Laid-Open No. 2004-20466 JP-A-10-160748

  Conventionally, it has been necessary to adjust a reference voltage by providing a reference voltage setting circuit including a resistor or the like in the integrated circuit to set a reference voltage necessary for generating the magnetic field detection signal. It was.

  In addition, for example, adjustment of the reference voltage must be performed every time the resistance element portion is changed. In such a case, the integrated circuit itself must be replaced, and the reference voltage should be changed without changing the resistance element portion. In some cases, it was necessary to replace the integrated circuit with a different reference voltage, and the conventional configuration could not standardize the integrated circuit, resulting in an increase in cost.

  In each of the above-mentioned patent documents, there is no recognition of the above-described conventional problems, and naturally no solution means is provided.

  Accordingly, the present invention is to solve the above-described conventional problems, and in particular, magnetic detection that can easily generate a magnetic field detection signal for a change in magnetic field strength of an external magnetic field as compared with the conventional one, and enables standardization of an integrated circuit. The object is to provide a device.

The magnetic detection device in the present invention is
Obtained from a resistance element portion including a first series circuit and a second series circuit constituted by a plurality of resistance elements, a first output extraction portion of the first series circuit, and a second output extraction portion of the second series circuit. An integrated circuit including a control unit for generating a magnetic field detection signal based on the output value obtained,
At least the first series circuit includes a magnetoresistive effect element using a magnetoresistive effect in which an electric resistance value changes with respect to an external magnetic field,
The first output waveform obtained from the first output extraction unit and the second output waveform obtained from the second output extraction unit are when the external magnetic field in the (+) direction has the first magnetic field strength, and When the external magnetic field in the (−) direction opposite to the (+) direction has the second magnetic field strength,
The first output waveform when the magnetic field strength is larger than the first magnetic field strength and the second magnetic field strength and when the magnetic field strength is smaller than the first magnetic field strength and the second magnetic field strength. And the magnitude relationship between the output values of the second output waveform is inverted,
The control unit generates the magnetic field detection signal based on the magnitude relationship of the output values.

  In the present invention, since the magnetic field detection signal is generated based on the magnitude relationship between the output values of the first output waveform and the second output waveform, the reference voltage is purposely included in the integrated circuit as conventionally. There is no need to provide a setting circuit, and the detection signal can be generated more easily than in the prior art. In the present invention, it is also possible to standardize the integrated circuit side.

In the present invention, the second series circuit also includes the magnetoresistive element,
One of the first output waveform and the second output waveform has an output increase in which the output value gradually increases as the magnetic field strength of the external magnetic field increases in the (+) direction and the (−) direction. With areas,
The other has an output drop region in which the output value gradually decreases as the magnetic field strength of the external magnetic field increases in the (+) direction and the (−) direction,
The output increase region and the output decrease region appearing on the external magnetic field side in the (+) direction intersect at the first magnetic field strength, and the output increase region and the output decrease region appearing on the external magnetic field side in the (−) direction are A configuration that intersects at the second magnetic field strength is preferable.

In the present invention, the first series circuit includes a first magnetoresistance effect element and a first fixed resistance element, and the second series circuit includes a second magnetoresistance effect element and a second fixed resistance. A first magnetoresistive effect element and the second fixed resistance element on one of the input terminal side and the ground terminal side, and the second magnetoresistive effect element and the first on the other side. Fixed resistance elements are connected respectively.
The first magnetoresistive effect element and the second magnetoresistive effect element have the same film configuration, and the first fixed resistance element and the second fixed resistance element have the same film configuration, as described above. The first output waveform and the second output waveform having an output increase region or an output decrease region can be appropriately obtained, and variations in temperature coefficient (TCR) can be suppressed, which is preferable.

  Further, in the present invention, the terminal portion that can be connected to an adjustment resistor for adjusting the first magnetic field strength and the second magnetic field strength is at least one of the first series circuit and the second series circuit. It is preferable to be connected to either of them.

  Thereby, even if the integrated circuit is standardized, the first magnetic field strength and the second magnetic field strength can be easily and freely adjusted simply by attaching an adjusting resistor having a predetermined resistance value to the terminal portion.

  In the present invention, the magnetoresistive element is preferably a GMR element utilizing a giant magnetoresistive effect (GMR effect). Thereby, it is possible to appropriately obtain an output waveform having a small hysteresis and appropriately generate a magnetic field detection signal with respect to a change in the magnetic field strength of the external magnetic field.

  In the present invention, the magnetoresistive element includes a pinned magnetic layer whose magnetization direction is fixed in the film thickness direction, a free magnetic layer whose magnetization direction varies with respect to an external magnetic field, the pinned magnetic layer, and the free magnetic layer. It has a laminated part with a nonmagnetic intermediate layer located between the layers, and the magnetization direction of the pinned magnetic layer and the free magnetic layer in the absence of a magnetic field is aligned in a direction perpendicular to the direction of the external magnetic field It is preferable. As a result, the first magnetic field strength and the second magnetic field strength can be set to substantially the same strength, and the timing of external magnetic field detection can be made substantially the same with bipolar.

  According to the magnetic detection device of the present invention, a magnetic field detection signal corresponding to a change in magnetic field strength of an external magnetic field can be generated more easily than in the prior art, and the integrated circuit can be standardized.

FIG. 1 is a circuit configuration diagram of a magnetic detection device 20 of the present embodiment.
A magnetic detection device 20 according to this embodiment shown in FIG. 1 includes a resistance element unit 21 and an integrated circuit (IC) 22.

  The resistance element section 21 includes a first series circuit 26 in which a first magnetoresistive element 23 and a first fixed resistance element 24 are connected in series via a first output extraction section 25, a second magnetoresistance A second series circuit 30 in which the effect element 27 and the second fixed resistance element 28 are connected in series via the second output extraction unit 29 is provided.

  As shown in FIG. 1, the integrated circuit 22 is provided with an input terminal (power source) 39, a ground terminal 42, and an external output terminal 40.

  As shown in FIG. 1, external terminals 51 and 52 for connecting an adjustment resistor (fixed resistance element) 50 in series with the first series circuit 26 of the resistance element section 21 are provided.

  The input terminal 39, the ground terminal 42, and the external output terminal 40 are exposed to the outside, and are electrically connected to terminal portions on the device side (not shown) by wire bonding, die bonding, or the like. The external terminals 51 and 52 are externally provided so that a purchaser of the magnetic detection device 20 can easily connect an adjustment resistor (fixed resistor) 50 in order to adjust the magnetic sensitivity of the magnetic detection device 20. It is desirable to be exposed.

  As shown in FIG. 1, a control unit 34 having a differential amplifier 35 and a comparator 38 is provided in the integrated circuit 22.

  A first output extraction section 25 of the first series circuit 26 and a second output extraction section 29 of the second series circuit 30 are connected to the input section of the differential amplifier 35, respectively.

  The input part of the comparator 38 is connected to the output part of the differential amplifier 35, and the output part of the comparator 38 is connected to the external output terminal 40.

  The first magnetoresistive element 23 and the second magnetoresistive element 27 are GMR elements that exhibit a giant magnetoresistive effect (GMR effect) based on a change in magnetic field strength of an external magnetic field.

  As shown in FIG. 10, the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 are both on the substrate 70 from below, the underlayer 60, the seed layer 61, the antiferromagnetic layer 62, and the fixed magnetic layer. 63, a nonmagnetic intermediate layer 64, a free magnetic layer 65, and a protective layer 66 are laminated in this order. The underlayer 60 is made of, for example, a nonmagnetic material of one or more elements selected from Ta, Hf, Nb, Zr, Ti, Mo, and W. The seed layer 61 is made of NiFeCr or Cr. The antiferromagnetic layer 62 includes an anti-ferromagnetic material containing an element α (where α is one or more of Pt, Pd, Ir, Rh, Ru, and Os) and Mn. Or, element α and element α ′ (where element α ′ is Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni) , Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, and rare earth elements are one or more elements) and It is formed of an antiferromagnetic material containing Mn. For example, the antiferromagnetic layer 62 is made of IrMn or PtMn. The pinned magnetic layer 63 and the free magnetic layer 65 are made of a magnetic material such as a CoFe alloy, a NiFe alloy, or a CoFeNi alloy. The nonmagnetic intermediate layer 64 is made of Cu or the like. The protective layer 66 is made of Ta or the like. The pinned magnetic layer 63 and the free magnetic layer 65 have a laminated ferrimagnetic structure (magnetic layer / nonmagnetic layer / magnetic layer laminated structure in which the magnetization directions of two magnetic layers sandwiching the nonmagnetic layer are antiparallel) It may be. The pinned magnetic layer 63 and the free magnetic layer 65 may have a laminated structure of a plurality of magnetic layers made of different materials.

  In the first magnetoresistive element 23 and the second magnetoresistive element 27, the antiferromagnetic layer 62 and the pinned magnetic layer 63 are formed in contact with each other. An exchange coupling magnetic field (Hex) is generated at the interface between the layer 62 and the pinned magnetic layer 63, and the magnetization direction of the pinned magnetic layer 63 is fixed in one direction. In FIG. 9, the magnetization direction 63a of the pinned magnetic layer 63 is indicated by the arrow direction. In the first magnetoresistive element 23 and the second magnetoresistive element 27, the magnetization direction 63a of the pinned magnetic layer 63 is the X2 direction shown in the drawing.

  In addition, the magnetization direction 65a of the free magnetic layer 65 in the absence of a magnetic field (when no external magnetic field is applied) is the X2 direction in the drawing for both the first magnetoresistance effect element 23 and the second magnetoresistance effect element 27. . Therefore, in the non-magnetic state, the magnetization direction 63a of the pinned magnetic layer 63 and the magnetization direction 65a of the free magnetic layer 65 are in a parallel state.

  The magnetization directions 63a and 65a of the pinned magnetic layer 63 and the free magnetic layer 65 may be antiparallel. Hereinafter, the magnetization direction 63a of the pinned magnetic layer 63 and the magnetization direction 65a of the free magnetic layer 65 will be described. Will be described as being in a parallel state.

  The external magnetic field H acts in the Y direction shown orthogonal to the X direction shown. Here, in the Y direction, the direction toward the paper surface in FIG. 10 is defined as the (+) direction, and the direction away from the paper surface is defined as the (−) direction.

  As shown in FIG. 10, when the magnetization direction 63a of the pinned magnetic layer 63 and the magnetization direction 65a of the free magnetic layer 65 are in parallel, the electric resistance values of the magnetoresistive elements 23 and 27 are the smallest.

  When the external magnetic field H acts in the (+) direction, the magnetization direction 65a of the free magnetic layer 65 changes toward the (+) direction, and the magnetic field strength of the external magnetic field H in the (+) direction increases as the magnetic field strength increases. The electric resistance values of the magnetoresistive effect elements 23 and 27 are gradually increased.

  When the external magnetic field H acts in the (−) direction, the magnetization direction 65a of the free magnetic layer 65 changes toward the (−) direction, and the magnetic field strength of the external magnetic field H in the (−) direction increases. The electric resistance values of the magnetoresistive effect elements 23 and 27 are gradually increased.

  On the other hand, the electrical resistance value of the first fixed resistance element 24 and the second fixed resistance element 28 does not change with respect to the external magnetic field H.

  As shown in FIG. 10, the first fixed resistance element 24 and the second fixed resistance element 28 are formed with the same material configuration as the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27. Unlike the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27, a free magnetic layer 65 and a nonmagnetic intermediate layer 64 are reversely stacked. That is, the first fixed resistance element 24 and the second fixed resistance element 28 are, from the bottom, the underlayer 60, the seed layer 61, the antiferromagnetic layer 62, the fixed magnetic layer 63, the free magnetic layer 65, and the nonmagnetic intermediate layer 64. , And the protective layer 66 in this order. Since the free magnetic layer 65 is formed in contact with the pinned magnetic layer 63, unlike the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27, the magnetization does not fluctuate with respect to an external magnetic field and is no longer free. It does not function as the magnetic layer 65 (like the pinned magnetic layer 63, it is a magnetic layer whose magnetization direction is fixed).

  As described above, the first fixed resistance element 24 and the second fixed resistance element 28 are formed of the same material structure as that of the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27, so that the first fixed resistance element 24 and the second fixed resistance element 28 are formed. Variations in the temperature coefficient (TCR) of the magnetoresistive effect element 23 and the second magnetoresistive effect element 27 and the temperature coefficient of the fixed resistance elements 24 and 27 can be suppressed. Further, the first magnetoresistance effect element 23, the second magnetoresistance effect element 27, the first fixed resistance element 24, and the second fixed resistance element 28 shown in FIG. All of them can be set to the same electric resistance value at zero external magnetic field.

  The first magnetoresistance effect element 23 and the second fixed resistance element 28 are connected to either the input terminal 39 or the ground terminal 42, and the second magnetoresistance effect element 27 and the first fixed resistance element 24 are connected to the other, respectively. However, in the following, as shown in FIG. 1, the first magnetoresistance effect element 23 and the second fixed resistance element 28 are on the ground terminal 42 side, and the second magnetoresistance effect element 27 and the first fixed resistance element 24 are on the input terminal. The description will be made assuming that they are respectively connected to the 39 side.

  When the adjustment resistor 50 (adjustment resistor R = 0Ω) is not connected to the external terminals 51 and 52 shown in FIG. 1 and the terminal portions 51 and 52 are short-circuited, the first output of the first series circuit 26 is obtained. The first output waveform A with respect to the external magnetic field H obtained from the extraction unit 25 and the second output waveform B with respect to the external magnetic field H obtained from the second output extraction unit 29 of the second series circuit 30 are shown in FIG. Appears in state. FIG. 2 shows the prior art.

  As shown in FIG. 2, when the external magnetic field H is zero, the output value of the first output waveform A and the output value of the second output waveform B become the same value, but otherwise, the first output waveform The output value of A is always larger than the output value of the second output waveform B. Therefore, the differential output obtained from the differential amplifier 35 is always 0 (V) or more or 0 (V) or less with respect to the external magnetic field H. Therefore, in the case of the output waveform of FIG. 2, in order to set the reference voltage for the differential output obtained from the differential amplifier 35 to a position higher than 0 (V) or a position lower than 0 (V). It is necessary to provide a reference voltage setting circuit composed of a resistor or the like in one integrated circuit.

  In this embodiment, the adjustment resistor 50 is connected to the external terminals 51 and 52 shown in FIG. As a result, the midpoint potential obtained from the first output extraction unit 25 of the first series circuit 26 changes. In the configuration of FIG. 1, the midpoint potential obtained from the first output extraction unit 25 is reduced by connecting the adjustment resistor 50.

  FIG. 3 is a graph showing a first output waveform A and a second output waveform B when an adjustment resistor 50 having a resistance value R of 91Ω is connected, and FIG. 4 is an adjustment resistor 50 having a resistance value R of 200Ω. FIG. 5 is a graph showing the first output waveform A and the second output waveform B when connected, and FIG. 5 shows the first output waveform A and the second output waveform A when the adjustment resistor 50 having a resistance value R of 330Ω is connected. FIG. 6 is a graph showing the first output waveform A and the second output waveform B when the adjustment resistor 50 having a resistance value R of 430Ω is connected, and FIG. 7 shows the resistance value. It is a graph which shows the 1st output waveform A and the 2nd output waveform B at the time of connecting the adjustment resistance 50 whose R is 560 (ohm). 3 to 7 are simulation results, and the specific resistance value of the adjustment resistor 50 listed here is an example, and does not regulate the resistance range of the adjustment resistor 50, and will be described later. The values of the magnetic field strengths H1 and H2 (sensitivity magnetic field) are also examples.

  The second output waveform B does not change in FIGS. 2 to 7, but the first output waveform A is output as a whole by connecting the adjusting resistor 50 and gradually increasing the adjusting resistor. The value decreases and falls in the direction of the vertical axis in the figure. The first output waveform A and the second output waveform B intersect at two points, and the intersection changes.

  For example, referring to FIG. 4 as an example, the first output waveform A includes a first output increase area A1 in which the output value gradually increases as the magnetic field strength of the external magnetic field H increases in the (+) direction, A second output increase region A2 in which the output value gradually increases as the magnetic field strength of the external magnetic field H increases in the (−) direction.

  The second output waveform B includes the first output drop region B1 in which the output value gradually decreases as the magnetic field strength of the external magnetic field H increases in the (+) direction, and the magnetic field strength of the external magnetic field H is ( A second output drop region B2 in which the output value gradually decreases as the value increases in the-) direction.

  As shown in FIG. 4, the first output increase region A1 and the first output decrease region B1 intersect when the external magnetic field H in the (+) direction is the first magnetic field strength H1, and the second output increase region A1 The output increase region A2 and the second output decrease region B2 intersect when the external magnetic field H in the (−) direction is the second magnetic field strength H2.

  Therefore, as shown in FIG. 4, when the magnetic field strength is larger than the first magnetic field strength H1 and the second magnetic field strength H2, the output value of the first output waveform A is the second output waveform B. When the magnetic field strength is always higher than the output value and smaller than the first magnetic field strength H1 and the second magnetic field strength H2, the output value of the first output waveform A is the second output waveform B. It is always lower than the output value.

  Therefore, the differential output obtained by the differential amplifier 35 is always positive when the magnetic field strength of the external magnetic field H is larger than 20 Oe in absolute value as shown in FIG. 8, and the magnetic field strength is smaller than 20 Oe in absolute value. Sometimes it is negative.

  In the comparator 38 shown in FIG. 1, for example, an ON signal is generated when the differential output is a positive value, and an OFF signal is generated when the differential output is a negative value. Thereby, when the magnetic field strength of the external magnetic field H becomes larger than 20 Oe in absolute value, the differential output becomes a positive value and an ON signal is generated, and when the magnetic field strength of the external magnetic field H becomes smaller than 20 Oe in absolute value, the differential output becomes differential. The output is negative and an off signal is generated.

  As described above, in the present embodiment, the first output waveform A and the second output waveform B intersect when the first magnetic field strength H1 and the second magnetic field strength H2, and the first magnetic field. The first output waveform A when the magnetic field intensity is larger than the intensity H1 and the second magnetic field intensity H2 and when the magnetic field intensity is smaller than the first magnetic field intensity H1 and the second magnetic field intensity H2. Since the magnitude relationship between the output values of the second output waveform B and the second output waveform B is reversed, the control unit 34 generates the magnetic field detection signal (on signal, off signal) with respect to the change in the magnetic field strength of the external magnetic field H. Whether the output value of the first output waveform A is larger or smaller than the output value of the second output waveform B (whether the differential output in FIG. 8 becomes a positive value or a negative value). By determining, the magnetic field detection signal can be generated.

  Therefore, unlike the conventional case, the reference voltage setting circuit does not have to be provided in the integrated circuit 22, and it is not necessary to adjust the reference voltage each time the resistance element portion 21 is changed. Compared with this, the magnetic field detection signal can be easily generated.

  In FIG. 4, the magnetic field strengths H1 and H2 (sensitivity magnetic field) of the external magnetic field H at which the ON signal and the OFF signal are switched are ± 20 Oe. However, if the resistance value R of the adjustment resistor 50 is changed, the magnetic field strength H1 is changed. , H2 (sensitivity magnetic field) also changes.

  3, the magnetic field strengths H1, H2 (sensitivity magnetic field) are ± 10 Oe, in FIG. 5, the magnetic field strengths H1, H2 (sensitivity magnetic field) are ± 30 Oe, and in FIG. 6, the magnetic field strengths H1, H2 (sensitivity). Magnetic field) is ± 40 Oe, and in FIG. 7, the magnetic field strengths H1 and H2 (sensitivity magnetic fields) are ± 50 Oe.

  Therefore, even if the integrated circuit 22 side is standardized, the magnetic field strengths H1 and H2 (sensitivity magnetic fields) can be easily and freely changed by changing the resistance value R of the adjustment resistor 50. In this way, since the integrated circuit 22 can be standardized and manufactured, the manufacturing cost can be reduced.

  In the comparator 38, as shown in FIG. 8, the threshold for generating the on signal (threshold level LV1) is set to a value slightly larger than the differential output 0 (V), and the threshold for generating the off signal ( The threshold level LV2) is set to a value slightly smaller than the differential output 0 (V) (Schmitt trigger input). Thereby, chattering can be prevented.

  In the configuration shown in FIG. 1, the first magnetoresistive effect element 23, the second magnetoresistive effect element 27, the first fixed resistance element 24, and the second fixed resistance element 28 are adjusted to have the same resistance value. However, for example, by making the resistance values of the magnetoresistive effect elements 23 and 27 and the fixed resistance elements 24 and 28 different from each other, the adjustment resistor 50 is not provided (the external terminals 51 and 52 are short-circuited). As shown in FIGS. 3 to 7, the first output waveform A and the second output waveform B can be crossed by the first magnetic field strength H1 and the second magnetic field strength H2.

  However, even in the case of the above configuration, if external terminals 51 and 52 are provided as shown in FIG. 1 and the adjustment resistor 50 can be connected, the integrated circuit 22 side can be standardized easily and freely. The magnetic field strengths H1 and H2 (sensitivity magnetic fields) can be changed.

  Further, since the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27 have the same film configuration, variation in temperature coefficient (TCR) can be reduced. Further, since the first fixed resistance element 24 and the second fixed resistance element 28 also have the same film configuration, variation in temperature coefficient (TCR) can be reduced. At this time, the first fixed resistance element 24 and the second fixed resistance element 28 may have a material structure different from that of the first magnetoresistive effect element 23 and the second magnetoresistive effect element 27, but will be described with reference to FIG. As described above, by using the same material configuration, it is possible to easily make the resistance values of all the resistance elements constant in the absence of a magnetic field, and to more effectively reduce the variation in temperature coefficient (TCR). Then, by providing external terminals 51 and 52 as shown in FIG. 1 and allowing the adjustment resistor 50 to be connected, the magnetic field strengths H1 and H2 (sensitivity) are obtained while having a stable temperature coefficient (TCR). A magnetic detection device capable of easily and freely changing the magnetic field) can be obtained, and is more preferable.

  The magnetoresistive effect elements 23 and 27 may be, for example, AMR elements. However, as shown in FIG. 10, the GMR element using the giant magnetoresistive effect (GMR effect) can appropriately output an output waveform with small hysteresis. The detection signal for the change in the magnetic field strength of the external magnetic field H can be appropriately generated, which is preferable.

  As shown in FIG. 10, the magnetoresistive elements 23 and 27 formed of GMR elements have a pinned magnetic layer 63 whose magnetization direction is fixed in the film thickness direction, and a magnetization direction that fluctuates with respect to an external magnetic field. The pinned magnetic layer includes a laminated portion of a free magnetic layer 65, the pinned magnetic layer 63, and a nonmagnetic intermediate layer 64 positioned between the free magnetic layer 65 and has no magnetic field (external magnetic field H is zero). It is preferable that the magnetization directions of 63 and the free magnetic layer 65 are aligned in a direction orthogonal to the direction of the external magnetic field H (Y direction in the drawing) (X direction in the drawing). In addition to the GMR element, a TMR element can be used.

  As a result, as shown in FIG. 4, the first output waveform A and the second output waveform B can be made substantially V-shaped or reverse substantially V-shaped. Moreover, as shown in FIGS. 3 to 7, the first magnetic field strength H1 and the second magnetic field strength H2 can be set to substantially the same strength. Therefore, it is possible to generate and output the detection signal at the same timing both when the external magnetic field H acts in the (+) direction and when the external magnetic field H acts in the (−) direction.

The magnetic detection device 20 of the present embodiment is used for, for example, opening / closing detection of portable devices such as a folding cellular phone and electrical appliances such as a refrigerator. In such a case, the magnetic detection device 20 has a (+) direction or (−). The external magnetic field H acts only from either direction from the direction. Since the magnetic detection device 20 of the present embodiment can perform bipolar detection, the external magnetic field H can be detected regardless of which of the external magnetic field H in the (+) direction and the external magnetic field in the (−) direction acts on the magnetic detection device 20. The detection can be performed at the same timing with bipolar. Therefore, the external magnetic field H can be detected even if one of the magnetic detection device and the magnet is attached in reverse with respect to the predetermined attachment direction, and therefore the workability of the attachment can be improved.
Further, the magnetic detection device of the present embodiment can be applied to uses that require bipolar detection.

  In the embodiment of FIG. 1, external terminals 51 and 52 are connected to the first series circuit 26, but they may be connected to the second series circuit 30, and the first series circuit 26 may be connected to the first series circuit 26. It may be connected to both the series circuit 26 and the second series circuit 30.

  In the present embodiment, the magnetoresistive effect elements 23 and 27 are provided in both the first series circuit 26 and the second series circuit 30. For example, the two resistance elements constituting the second series circuit 30 are both combined. It may be a fixed resistance element. At this time, the second output waveform B is a straight line with a constant output value as shown in FIG. 9, but the first output waveform A is substantially V-shaped, and the first output waveform A and the second output waveform A Since the output waveform B intersects with the external magnetic field H in the (+) direction and the (−) direction at the magnetic field strengths H1 and H2 (sensitivity magnetic fields), respectively, as described with reference to FIGS. When generating a detection signal for a change in magnetic field strength of the external magnetic field H, whether the output value of the first output waveform A is larger or smaller than the output value of the second output waveform B (difference) The detection signal can be generated by determining whether the dynamic output is a positive value or a negative value.

The circuit block diagram of the magnetic detection apparatus of this embodiment, A graph showing the relationship between the external magnetic field H and the first output waveform A and the second output waveform B when the adjustment resistor R is 0Ω; 2 is a graph showing the relationship between the external magnetic field H and the first output waveform A and the second output waveform B when the adjustment resistor R is made larger than that in FIG. 3 is a graph showing the relationship between the external magnetic field H and the first output waveform A and the second output waveform B when the adjustment resistor R is made larger than that in FIG. 4 is a graph showing the relationship between the external magnetic field H and the first output waveform A and the second output waveform B when the adjustment resistor R is made larger than that in FIG. A graph showing the relationship between the external magnetic field H and the first output waveform A and the second output waveform B when the adjustment resistor R is made larger than that in FIG. 6 is a graph showing the relationship between the external magnetic field H and the first output waveform A and the second output waveform B when the adjustment resistor R is larger than that in FIG. A graph showing the relationship between the differential output and the external magnetic field H; A graph showing a relationship between the first output waveform A and the second output waveform B, which is different from those shown in FIGS. Sectional drawing of the magnetoresistive effect element and fixed resistance element of this embodiment,

Explanation of symbols

20 Magnetic Detection Element Device 21 Resistance Element Unit 22 Integrated Circuit (IC)
23 1st magnetoresistive effect element 24 1st fixed resistance element 25 1st output extraction part 26 1st series circuit 27 2nd magnetoresistance effect element 28 2nd fixed resistance element 29 2nd output extraction part 30 2nd series circuit 34 Control Unit 35 differential amplifier 38 comparator 39 input terminal 40 external output terminal 42 ground terminal 50 adjusting resistors 51 and 52 external terminal 62 antiferromagnetic layer 63 pinned magnetic layer 64 nonmagnetic intermediate layer 65 free magnetic layer 66 protective layer 70 substrate

Claims (6)

Obtained from a resistance element portion including a first series circuit and a second series circuit constituted by a plurality of resistance elements, a first output extraction portion of the first series circuit, and a second output extraction portion of the second series circuit. An integrated circuit including a control unit for generating a magnetic field detection signal based on the output value obtained,
At least the first series circuit includes a magnetoresistive effect element using a magnetoresistive effect in which an electric resistance value changes with respect to an external magnetic field,
The first output waveform obtained from the first output extraction unit and the second output waveform obtained from the second output extraction unit are when the external magnetic field in the (+) direction has the first magnetic field strength, and When the external magnetic field in the (−) direction opposite to the (+) direction has the second magnetic field strength,
The first output waveform when the magnetic field strength is larger than the first magnetic field strength and the second magnetic field strength, and when the magnetic field strength is smaller than the first magnetic field strength and the second magnetic field strength. And the magnitude relationship between the output values of the second output waveform is inverted,
The control unit generates the magnetic field detection signal based on a magnitude relationship between the output values. The second series circuit also includes the magnetoresistive effect element,
One of the first output waveform and the second output waveform has an output increase in which the output value gradually increases as the magnetic field strength of the external magnetic field increases in the (+) direction and the (−) direction. With areas,
The other has an output drop region in which the output value gradually decreases as the magnetic field strength of the external magnetic field increases in the (+) direction and the (−) direction,
The output increase region and the output decrease region appearing on the external magnetic field side in the (+) direction intersect at the first magnetic field strength, and the output increase region and the output decrease region appearing on the external magnetic field side in the (−) direction are The magnetic detection device according to claim 1, which intersects at the second magnetic field strength. The first series circuit includes a first magnetoresistance effect element and a first fixed resistance element, and the second series circuit includes a second magnetoresistance effect element and a second fixed resistance element, The first magnetoresistance effect element and the second fixed resistance element are provided on either the input terminal side or the ground terminal side, and the second magnetoresistance effect element and the first fixed resistance element are provided on the other side. Each connected,
3. The first magnetoresistive effect element and the second magnetoresistive effect element have the same film configuration, and the first fixed resistance element and the second fixed resistance element have the same film configuration. Magnetic detection device.   A terminal portion capable of connecting an adjustment resistor for adjusting the first magnetic field strength and the second magnetic field strength is connected to at least one of the first series circuit and the second series circuit. The magnetic detection device according to claim 1, wherein the magnetic detection device is provided.   The magnetic detection device according to claim 1, wherein the magnetoresistive element is a GMR element using a giant magnetoresistive effect (GMR effect).   The magnetoresistive element includes a pinned magnetic layer whose magnetization direction is fixed in a film thickness direction, a free magnetic layer whose magnetization direction varies with respect to an external magnetic field, and the pinned magnetic layer and the free magnetic layer. 6. The magnetization direction of the pinned magnetic layer and the free magnetic layer in the absence of a magnetic field is provided in a direction perpendicular to the direction of the external magnetic field. Magnetic detection device.

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