JP2011180001A - Rotation sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a rotation sensor capable of size reduction, while improving the detection accuracy of rotation angle. <P>SOLUTION: The rotation sensor includes a sensor chip 5, having a magnetoresistive element region E1 where magnetoresistive elements R1-R8 are disposed so as to show the phase difference between output signals of the respective magnetoresistive elements and a Hall element region E2, where Hall elements H1 and H2 are disposed to show the phase difference between output signals of the respective Hall elements, wherein additionally, the magnetoresistive element region and the Hall element region overlap, at least in section; a comparison section 53 for showing results of comparing respective output levels of the respective Hall elements with a threshold level; an angle calculation section 60 for calculating an operation angle ϕ, corresponding to a relative rotation angle θ, by using the output signals from the respective magnetoresistive elements; and an output section 70 for comparing the calculated angle with a threshold angle and outputting a signal corresponding to the relative rotation angle, by using the comparison results and the comparison results of the comparison section 53. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a sensor chip having a magnetoresistive element and a Hall element, rotating relative to the magnetism generating unit, and using the output signals from the magnetoresistive element and the Hall element to the magnetism generating unit. The present invention relates to a rotation sensor that detects a relative rotation angle.

  Conventionally, what is shown in FIG. 30 is known as this kind of rotation sensor (patent document 1). As shown in FIG. 30A, this device is configured by arranging one magnetic sensor 100 and a Hall element 101 on the surface of a printed circuit board 104. The magnetic sensor 100 is disposed at a position facing the rotating surface of the permanent magnet 107 so that a magnetic field 106 generated from the permanent magnet 107 and parallel to the surface of the printed circuit board 104 can be detected. The Hall element 101 is arranged outside the permanent magnet 107 so that a magnetic field 105 generated from the permanent magnet 107 and perpendicular to the surface of the printed circuit board 104 can be detected. As shown in FIG. 30B, the Hall element 101 includes two horizontal Hall elements 102 and 103. The horizontal Hall elements 102 and 103 are arranged at an angle γ in the plane direction with respect to the magnetic sensor 100.

  When the permanent magnet 107 rotates once, the magnetic sensor 100 outputs a signal with one wavelength having an electrical angle of 180 °, and the horizontal Hall elements 102 and 103 each output a signal with one wavelength having an electrical angle of 360 °. . Further, the rotation angle α of the permanent magnet 107 is obtained in an angle range of 180 ° at the maximum based on the output signal of the magnetic sensor 100, and based on the magnitude relationship between the output values of the horizontal Hall elements 102 and 103, the permanent magnet 107. It is determined to which range the rotation angle α of 0 ° ≦ α ≦ 90 °, 90 ° ≦ α ≦ 180 °, 180 ° ≦ α ≦ 270 ° and 270 ° ≦ α ≦ 360 ° belongs. Further, it is described that it is desirable to set the arrangement angle γ of the horizontal Hall elements 102 and 103 with respect to the magnetic sensor 100 to 90 ° in order to increase the determination accuracy of the rotation angle range.

JP-A-11-94512 (paragraphs 22 to 24, FIGS. 4 and 5).

By the way, in the conventional device described above, when the arrangement angle γ of the horizontal Hall elements 102 and 103 with respect to the magnetic sensor 100 is set to 90 °, the horizontal Hall elements 102 and 103 are arranged below and in the center of the permanent magnet 107. There must be.
However, in a state where the horizontal Hall elements 102 and 103 are arranged below and in the center of the permanent magnet 107, the magnetic field 105 generated from the permanent magnet 107 is not applied perpendicularly to the horizontal Hall elements 102 and 103. It becomes impossible to determine the range of the rotation angle of the permanent magnet 107 based on the outputs of the horizontal Hall elements 102 and 103. Further, if the angle γ is set to 90 ° in the arrangement range where the magnetic field 105 is applied perpendicularly to each of the horizontal Hall elements 102 and 103, the interval between the horizontal holes becomes large, making it difficult to make a single chip, and the printed circuit board 104 is Since it becomes larger, the rotation sensor becomes larger.
That is, it has been difficult to reduce the size of the conventional one while increasing the detection accuracy of the rotation angle.

  Accordingly, the present invention has been made to solve the above-described problem, and an object thereof is to realize a rotation sensor that can be miniaturized while improving the detection accuracy of the rotation angle.

  In order to achieve the above object, a first feature of the present invention is that a magnetoresistive element (R1 to R8) that generates a magnetoresistive effect by magnetism generated from a magnetism generating unit (2) and a Hall effect by the magnetism are provided. A rotation sensor (1) having a Hall element (H1, H2) to be generated, and detecting a relative rotation angle (θ) with respect to the magnetism generation unit using output signals from the magnetoresistive element and the Hall element; A magnetoresistive element region (E1) in which a plurality of magnetoresistive elements are arranged so as to produce a phase difference between output signals of the respective magnetoresistive elements, and a plurality of Hall elements produce a phase difference between output signals of the respective Hall elements. A sensor chip (5) having a Hall element region (E2) arranged in such a manner and at least a part of the magnetoresistive element region and the Hall element region are overlapped with each other, The comparator (53) that compares the output level with the threshold level and outputs a comparison result for each Hall element, and calculates the angle (φ) corresponding to the relative rotation angle using each output signal of each magnetoresistive element. The angle calculation unit (60) compares the calculated value calculated by the angle calculation unit with a threshold value, and outputs a signal corresponding to the relative rotation angle using the comparison result and the comparison result of the comparison unit. And an output unit (70).

According to the first feature described above, since at least a part of the magnetoresistive element region and the Hall element region overlap each other, the rotation sensor can be reduced in size.
Moreover, when outputting a signal corresponding to the relative rotation angle, in addition to the comparison result between each output level of each Hall element and the threshold level, the comparison result between the angle calculated by the angle calculation unit and the threshold angle is also used. Therefore, the detection accuracy of the relative rotation angle can be increased.
That is, when there is an unstable part in the comparison result between each output level of each Hall element and the threshold level, the part can be supplemented by the comparison result between the calculation value calculated by the angle calculation unit and the threshold value. Therefore, the detection accuracy of the relative rotation angle can be increased.

  A second feature of the present invention is that, in the first feature described above, substantially the entire region of the Hall element region (E2) is overlapped with the magnetoresistive device region (E1).

According to the second feature described above, the rotation sensor can be further reduced in size because substantially the entire Hall element region is overlapped with the magnetoresistive element region.
In addition, since the same rotation sensor can be used in common even if the diameter of the magnetism generating portion is different, there is no need to manufacture a different rotation sensor for each diameter of the permanent magnet.
Therefore, the manufacturing cost of the rotation sensor can be reduced.

  According to a third feature of the present invention, in the first or second feature described above, the magnetoresistive element region (E1) and the Hall element region (E2) are provided with a relative rotation axis (C1 ) In the direction corresponding to the direction.

  According to the third feature described above, since the magnetoresistive element region and the Hall element region are overlapped in a direction corresponding to the relative rotation axis direction with respect to the magnetism generating unit, the rotation sensor occupies the periphery of the relative rotation axis. The area can be reduced.

  According to a fourth feature of the present invention, in any one of the first to third features described above, the magnetoresistive element region (E1) and the Hall element region (E2) are relatively rotated by the magnetic generator (2). It exists in arrange | positioning substantially parallel to a surface (2c).

  According to the fourth feature described above, since the magnetoresistive element region and the Hall element region are disposed substantially parallel to the relative rotation surface of the magnetism generating unit, each magnetoresistive element and each Hall element are provided with the magnetizing unit. Thus, it is possible to detect magnetism generated substantially in parallel with the magnetoresistive element region and the Hall element region.

  According to a fifth feature of the present invention, in any one of the first to fourth features described above, the magnetoresistive element region (E1) is located on the surface (5a) side of the sensor chip (5) and the Hall element region. (E2) is disposed on the back surface (5b) side of the sensor chip, and the surface of the sensor chip is disposed so as to face the relative rotation surface (2c) of the magnetism generation unit (2). It is in.

  A sixth feature of the present invention is that in any one of the first to fourth features described above, the magnetoresistive element region (E1) is located on the surface (5a) side of the sensor chip (5), and the Hall element region. (E2) is disposed on the back surface (5b) side of the sensor chip, and the back surface of the sensor chip is disposed so as to face the relative rotation surface (2c) of the magnetism generator (2). It is in.

  According to the fifth or sixth feature described above, the relative rotation angle can be detected regardless of which one of the front surface and the back surface of the sensor chip is opposed to the relative rotation surface of the magnetism generator.

  According to a seventh feature of the present invention, in any one of the first to sixth features described above, the magnetism generator (2) has different magnetic poles (2a) divided in the radial direction of the relative rotation surface (2c). , 2b).

  According to the seventh feature described above, it is possible to detect the relative rotation angle with respect to the magnetism generator having different magnetic poles divided in the radial direction of the relative rotation surface.

  According to an eighth feature of the present invention, in any one of the first to sixth features described above, the magnetism generator (2) has different magnetic poles arranged in the circumferential direction of the rotating body (6a) that rotates relative to each other ( 2a, 2b).

  According to the eighth feature described above, it is possible to detect the relative rotation angle with respect to the magnetic generator having different magnetic poles arranged in the circumferential direction of the rotating body that rotates relatively.

  A ninth feature of the present invention is that, in the eighth feature described above, the sensor chip (5) is disposed between the different magnetic poles (2a, 2b).

  According to the ninth feature described above, since the sensor chip is arranged between the different magnetic poles arranged on the outer periphery of the rotating body, the magnetism generated between the different magnetic poles is affected by the magnetoresistive element region and the Hall element region of the sensor chip. Can be applied in parallel. Moreover, the space occupied by the rotating body and the sensor chip can be compressed in the direction of the relative rotation axis of the rotating body.

  According to a tenth feature of the present invention, in any one of the first to ninth features described above, the magnetism generator (2) is multipolar.

  According to an eleventh feature of the present invention, in any one of the first to tenth features described above, each of the magnetoresistive elements (R1 to R8) and each of the Hall elements (H1, H2) includes the magnetoresistive element region ( E1) and the Hall element region (E2) are arranged so as to mainly detect a change in magnetic flux density of the magnetic field (B1) parallel to the Hall element region (E2).

According to the eleventh feature described above, since the change in the magnetic flux density of the magnetic field parallel to the magnetoresistive element region is mainly detected, the magnetoresistive effect in each magnetoresistive element can be increased.
Therefore, the detection accuracy of the relative rotation angle with respect to the magnetism generator can be increased.

  According to a twelfth feature of the present invention, in any one of the first to eleventh features described above, each of the Hall elements (H1, H2) has a phase difference of 90 ° between output signals of adjacent Hall elements. It is that it is arranged so that it comes out.

According to the above twelfth feature, a sine wave signal (sin signal) can be output from one of mutually adjacent Hall elements, and a cosine wave signal (cos signal) can be output from the other.
Therefore, by converting the above sine wave signal and cosine wave signal into pulse signals and using a combination of signal levels of both pulse signals, the relative rotation angles are 0 ° to 90 °, 90 ° to 180 °, 180 ° to It is possible to determine which quadrant (angle range) of 270 ° and 270 ° to 360 °.

  According to a thirteenth feature of the present invention, in any one of the first to twelfth features described above, each of the magnetoresistive elements (R1 to R8) is 45 ° between output signals of adjacent magnetoresistive elements. It exists in arrange | positioning so that a phase difference may come out.

According to the thirteenth feature described above, a sine wave signal (sin signal) is output from one of the mutually adjacent magnetoresistive elements, and a cosine wave signal (cos signal) whose phase is delayed by 45 ° from the sine wave signal. Can be output from the other.
Therefore, the relative rotation angle can be calculated using the above sine wave signal and cosine wave signal.

  According to a fourteenth feature of the present invention, in any one of the first to thirteenth features described above, the magnetoresistive element is half-bridged so that a 90 ° phase difference is produced between the output signals of the mutually adjacent magnetoresistive elements. The connected first and second half-bridge circuits are arranged so that the phase difference between the output signals of both half-bridge circuits is 45 °.

  According to the fourteenth feature described above, since each midpoint output of the first and second half bridge circuits oscillates around (1/2) of the voltage supplied to each half bridge circuit, the environmental temperature It is possible to suppress the offset of the output signal due to the change of the signal.

  According to a fifteenth feature of the present invention, in the fourteenth feature described above, a first full bridge circuit in which a pair of the first half bridge circuits are bridge-connected and a pair of the second half bridge circuits in a bridge connection The second full bridge circuit is arranged so that a phase difference of 45 ° is generated between the output signals of both full bridge circuits.

According to the fifteenth feature described above, the first and second half-bridge circuits each have a full-bridge circuit configuration, so that the amplitude of the output signal of each full-bridge circuit compared to the half-bridge circuit configuration. Can be doubled.
Therefore, since it is possible to detect even weak magnetism generated by the magnetism generation unit, it is possible to increase the detection sensitivity of the relative rotation angle with respect to the magnetism generation unit. Moreover, since the arrangement | positioning space | interval of a magnetic generation part and a sensor chip can be enlarged, the freedom degree of the arrangement position of a sensor chip increases.

  According to a sixteenth aspect of the present invention, in the fourteenth or fifteenth aspect described above, the magnetoresistive elements (R1 to R8) constituting the first and second half bridge circuits are alternately arranged concentrically. There is to be.

  According to the sixteenth feature described above, since the magnetoresistive elements constituting the first and second half bridge circuits are alternately arranged concentrically, the arrangement area of the magnetoresistive element region can be reduced. .

  According to a seventeenth feature of the present invention, in any one of the twelfth to sixteenth features described above, the signal generated by the output unit (70), the output signals of the Hall elements (H1, H2), There is a phase difference of 45 ° between the two.

  The output signal of the Hall element is an analog value of a sin signal or a cos signal with a period of 180 °, and is less sensitive than the magnetoresistive element. Therefore, the voltage offset is around 0 V, that is, near the point where the phase is switched by 180 °. The voltage tends to fluctuate under the influence of random noise. Therefore, when the output signal of the Hall element is 0V (threshold level) or more is determined as high level, and when it is less than 0V is determined as low level, a pulse signal (hereinafter referred to as a first pulse signal) is created. In the first pulse signal, the voltage near the point where the phase is switched by 180 ° may be unstable. For this reason, such an unstable region (the hatched region in FIG. 13) indicates which angle range the relative rotation angle is when the relative rotation angle of 0 to 360 ° is divided into 90 ° angular ranges. In order to increase the detection accuracy, it is desirable not to use it as an element for determining whether or not to enter.

  On the other hand, since the angle calculated by the angle calculation unit using the output signal of each highly sensitive magnetoresistive element is a multi-bit digital value, the calculation is performed by setting 1/2 of the calculated angle as a threshold angle. When it is determined that the angle is equal to or higher than the threshold angle as a high level and when the angle is less than the threshold angle, it is determined as a low level, a pulse signal without an unstable region (hereinafter referred to as a second pulse signal) can be created. . In addition, since the signal corresponding to the calculated angle is 45 degrees different in phase from each output signal of each Hall element, the second pulse signal is 45 degrees different in phase from the first pulse signal.

Therefore, when determining which angle range the relative rotation angle falls in, the signal level of the portion corresponding to the central 90 ° portion of the first pulse signal is used, and the unstable 45 ° signal at both ends. Do not use the level (total 90 °). And the part corresponding to 45 degrees of both ends uses the signal level of a 2nd pulse signal.
That is, according to the above-described seventeenth feature, when determining the angle range of the relative rotation angle, the angle range determination accuracy can be increased, and therefore the relative rotation angle detection accuracy can be increased.

  According to an eighteenth feature of the present invention, in any one of the twelfth to seventeenth features described above, the relative rotation angle (θ) of 0 to 360 ° is divided by a phase difference between output signals of the Hall elements. When n angle ranges are set by dividing the range of 0 to 360 ° by n, where n is a value, the combination of the comparison results in the comparison unit (53) and the output unit (70) is each angle range. Are different from each other.

  According to the eighteenth feature described above, the value obtained by dividing the relative rotation angle of 0 to 360 ° by the phase difference between the output signals of the Hall elements is n, and the range of 0 to 360 ° is divided by n. When n angle ranges are set, the combination of the comparison results in the comparison unit and the output unit is configured to be different in each angle range, so that the accuracy of determining the angle range can be increased. For example, the phase difference between output signals of each Hall element is 90 ° (n = 4), and the relative rotation angles are four angles of 0 to 90 °, 90 to 180 °, 180 to 270 °, and 270 to 360 °. When divided into ranges, the relative rotation angle is 180 °, but there is no possibility of erroneously outputting 0 ° as the calculated angle. Therefore, an accurate angle of 0 to 360 ° can be output.

  According to a nineteenth feature of the present invention, in any one of the first to eighteenth features described above, the angle calculator (60) includes the relative rotation angle (θ) and the magnetoresistive elements (R1 to R8). ) Is used to calculate an angle corresponding to the relative rotation angle by performing feedback control so that a deviation from an angle (φ) calculated using a plurality of output signals having a phase difference is reduced.

According to the nineteenth feature described above, the feedback control is performed so that the deviation between the relative rotation angle and the calculated angle is small, and the angle corresponding to the relative rotation angle is obtained, so the relative rotation angle is calculated with high accuracy. be able to.
In addition, an angle corresponding to a relative rotation angle of 0 to 360 ° can be output using the first and second comparison results and the calculated angle.

  According to a twentieth feature of the present invention, in any one of the first to nineteenth features described above, each of the Hall elements (H1, H2) is a vertical Hall element, and magnetic detection of each vertical Hall element is performed. The plane direction of the planes (HP1, HP2) is arranged so as to intersect the magnetoresistive element region (E1).

According to the twentieth feature described above, each Hall element is a vertical Hall element, and is arranged so that the surface direction of the magnetic detection surface of each vertical Hall element intersects the magnetoresistive element region. Magnetism parallel to the magnetoresistive element region can be detected by the magnetic detection surface of each Hall element.
Therefore, even when the magnetoresistive element region and the Hall element region are arranged in an overlapping manner, both element regions can detect magnetism, so that the sensor chip can be miniaturized in the plane direction (lateral width direction). .

  According to a twenty-first feature of the present invention, in any one of the first to twentieth features described above, each of the magnetoresistive elements (R1 to R8) and each of the Hall elements (H1, H2) is a semiconductor substrate (10). It is in being built in.

  According to the twenty-first feature described above, each magnetoresistive element and each Hall element can be integrated because each magnetoresistive element and each Hall element are built in the semiconductor substrate. Therefore, the trouble of individually positioning each magnetoresistive element and each Hall element can be saved.

  According to a twenty-second feature of the present invention, in any one of the first to twenty-first features described above, each of the Hall elements (H1, H2) has a CMOS transistor structure.

  According to the twenty-second feature described above, since each Hall element has a CMOS transistor structure, the manufacturing process can be simplified as compared with the bipolar structure, so that the manufacturing efficiency of the rotation sensor can be increased.

  In particular, as in the twenty-third feature of the present invention, each Hall element (H1, H2) has a high breakdown voltage CMOS transistor structure, whereby the N-type semiconductor region (Nwell) is deepened and the carrier mobility is high. Therefore, the magnetic detection sensitivity can be increased.

  According to a twenty-fourth aspect of the present invention, in the twenty-second or twenty-third aspect described above, the Hall element region (E2) is predetermined from a first conductivity type semiconductor substrate (10) and a surface layer portion in the semiconductor substrate. A second conductivity type semiconductor region (91) formed at a depth of the second conductivity type semiconductor region and the second conductivity type semiconductor region shallower than the second conductivity type semiconductor region in the second conductivity type semiconductor region The first conductivity type semiconductor region (92, 93, 99) formed in such a manner and a surface layer portion of the second conductivity type semiconductor region sandwiching the first conductivity type semiconductor region, and supplying current Second conductivity type impurity diffusion regions (97, 98) for contacts forming a pair and a second conductivity type for contacts forming a voltage output pair formed in a surface layer portion of the semiconductor region of the second conductivity type Impurity diffusion regions (95, 9 ) And has a said magnetoresistive element region (E1) is that at least a portion of which is formed to overlap the Hall element region via an insulating film (90).

According to the twenty-fourth feature, after the Hall element region is manufactured on the semiconductor substrate by the CMOS transistor manufacturing method, the insulating film is formed on the surface of the Hall element region, and the magnetoresistive element region is formed on the surface of the insulating film. Can be formed.
Therefore, since the magnetoresistive element region can be formed in the form of being stacked on the Hall element region, the manufacturing efficiency of the rotation sensor is increased as compared with the case where both element regions are individually formed in the planar direction (lateral direction). be able to.

  A twenty-fifth feature of the present invention is that, in any one of the first to twenty-fourth features described above, each of the magnetoresistive elements (R1 to R8) is made of a NiFe thin film.

  A twenty-sixth feature of the present invention is that, in any of the first to twenty-fourth features described above, each of the magnetoresistive elements (R1 to R8) is made of a NiCo thin film.

  According to the twenty-fifth or twenty-sixth feature described above, a weak magnetic field can be detected, so that the detection accuracy of the relative rotation angle can be increased.

  In addition, the code | symbol in each said parenthesis shows the correspondence with the specific means as described in embodiment mentioned later.

It is explanatory drawing which shows the main structures of the rotation sensor of 1st Embodiment with a block. It is explanatory drawing which shows an example of the use condition of the sensor chip shown in FIG. 1, (a) is a longitudinal cross-sectional view of a sensor chip and a permanent magnet, (b) is a top view of the permanent magnet shown to (a). It is a longitudinal cross-sectional view which shows the state which the permanent magnet shown to Fig.2 (a) rotated 180 degrees. It is explanatory drawing which shows the structure of a sensor chip typically, (a) is a top view, (b) is AA arrow sectional drawing of (a). (A) is a top view of the magnetoresistive element area | region E1 and Hall element area | region E2, (b) is explanatory drawing which shows the arrangement | positioning angle of Hall element H1, H2. It is a top view which shows typically the structure of AMR sensor M1. It is a top view which shows typically the structure of AMR sensor M2. It is an equivalent circuit of the AMR sensor M1. It is an equivalent circuit of the AMR sensor M2. It is explanatory drawing which shows each output signal of AMR sensor M1, M2 and Hall element H1, H2. It is explanatory drawing of Hall element H2, (a) is a top view which shows a part of Hall element H2 and its periphery, (b) is AA arrow sectional drawing of (a), (c) is (a). It is BB arrow sectional drawing of. It is explanatory drawing which shows the main electrical structures of the rotation sensor 1 with a block, and is a figure corresponding to FIG. It is explanatory drawing which shows output waveforms, such as a Hall element, (a) is an output waveform of Hall element H1, (b) is an output waveform of comparison circuit 53a, (c) is an output waveform of Hall element H2, (d) is The output waveform of the comparison circuit 53b, (e) is the output waveform of the calculation angle output from the angle calculation unit 60, (f) is the waveform indicating the comparison result between the calculation angle φ and the threshold angle φth shown in (e), ( g) is an output waveform of the output logic circuit 71. The relationship between the signal level of the first and second pulse signals VH1 and VH2 output from the comparison circuits 53a and 53b, the comparison result of the calculation angle φ and the threshold angle φth, and the angle range of the relative rotation angle θ (A) is a case where the Hall elements H1 and H2 are shifted by + 45 °, and (b) is a case where the Hall elements H1 and H2 are shifted by −45 °. It is explanatory drawing which shows typically the structure of the sensor chip with which the rotation sensor of 2nd Embodiment was equipped, (a) is a top view, (b) is AA arrow sectional drawing of (a). It is explanatory drawing which shows the main electrical structures of the rotation sensor 1 of 2nd Embodiment with a block. It is explanatory drawing which shows output waveforms, such as a Hall element in 2nd Embodiment, and is a figure corresponding to FIG. It is explanatory drawing which shows typically the structure of the sensor chip with which the rotation sensor of 3rd Embodiment was equipped, (a) is explanatory drawing at the time of shifting +45 degrees from the reference direction of relative rotation angle 0 degree, (b). These are explanatory drawings when the reference direction with a relative rotation angle of 0 ° is shifted by −45 °. (A) And (b) is explanatory drawing which shows arrangement | positioning of the Hall element with which the rotation sensor of 4th Embodiment was equipped. (A) And (b) is a longitudinal cross-sectional view of the sensor chip and permanent magnet with which the rotation sensor of 5th Embodiment was equipped. It is explanatory drawing which shows an example of the use condition of the sensor chip with which the rotation sensor of 6th Embodiment was equipped, (a) is a top view, (b) is AA arrow sectional drawing of (a). (A) And (b) is a top view of the sensor chip and rotary body with which the rotation sensor of the modification of 6th Embodiment was equipped. (A) And (b) is sectional drawing which shows an example of the use condition of the sensor chip with which the rotation sensor of 7th Embodiment was equipped. It is explanatory drawing which shows typically the structure of the sensor chip with which the rotation sensor of 8th Embodiment was equipped, (a) is a top view, (b) is AA arrow sectional drawing of (a). It is the equivalent circuit of the AMR sensor with which the rotation sensor of 9th Embodiment was equipped. It is explanatory drawing which shows typically the structure of the sensor chip with which the rotation sensor of 10th Embodiment was equipped, (a) is a top view, (b) is AA arrow sectional drawing of (a). It is explanatory drawing which abbreviate | omits some main electrical structures of the rotation sensor of 10th Embodiment, and shows with a block. It is explanatory drawing which shows the structure of the angle calculating part 60 with which the rotation sensor of 11th Embodiment was equipped with a block. It is explanatory drawing which shows the main electrical structures of the rotation sensor of 12th Embodiment with a block. It is explanatory drawing of the conventional rotation sensor.

<First Embodiment>
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing the main configuration of the rotation sensor of this embodiment in blocks. 2A and 2B are explanatory views showing an example of a usage state of the sensor chip shown in FIG. 1, wherein FIG. 2A is a longitudinal sectional view of the sensor chip and the permanent magnet, and FIG. 2B is a plan view of the permanent magnet shown in FIG. It is. FIG. 3 is a longitudinal sectional view showing a state in which the permanent magnet shown in FIG.

[Main configuration]
The main configuration of the rotation sensor of this embodiment will be described. As shown in FIG. 1, the rotation sensor 1 of this embodiment includes a sensor chip 5 and a detection circuit 50 electrically connected to the sensor chip 5. The sensor chip 5 includes two anisotropic magnetoresistive sensors (hereinafter referred to as AMR sensors) M1 and M2 made of magnetoresistive elements and two Hall elements H1 and H2.

  As shown in FIG. 2A, the sensor chip 5 is disposed at a position facing the relative rotation surface 2c along the diameter of the permanent magnet (magnetization generating unit) 2 to be detected. The sensor chip 5 is supported by a support member (not shown), and is fixed so that the arrangement position does not change. As shown in FIG. 2B, the permanent magnet 2 has a disc shape and has different magnetic poles divided in the radial direction of the relative rotation surface 2c. In this embodiment, the permanent magnet 2 is divided into two equal parts in the radial direction of the relative rotation surface 2c, one being an N-pole permanent magnet 2a and the other being an S-pole permanent magnet 2b. . As shown in FIG. 2A, the permanent magnet 2 is attached to the tip of the rotating shaft 3 and rotates in the direction indicated by the arrow F1.

  The permanent magnet 2 generates a magnetic field from the N-pole permanent magnet 2 a toward the S-pole permanent magnet 2 b, and generates a magnetic field B 1 parallel to the surface 5 a of the sensor chip 5. In the illustrated example, the magnetic field B1 passes through the Hall element H2 from the Hall element H1. When the permanent magnet 2 rotates 180 ° from the state shown in FIG. 2A as shown in FIG. 3, the direction of the magnetic field B1 changes by 180 °. In the illustrated example, the magnetic field B1 passes through the Hall elements H2 to H1.

  As shown in FIG. 1, the detection circuit 50 includes amplification units 51 and 52, an angle calculation unit 60, a comparison unit 53, and an output unit 70. The amplifying unit 51 amplifies output signals output from the AMR sensors M1 and M2. The angle calculation unit 60 calculates a relative rotation angle (hereinafter also referred to as an input angle) θ of the permanent magnet 2 using the amplified signal output from the amplification unit 51. The amplifying unit 52 amplifies output signals output from the Hall elements H1 and H2. The comparison unit 53 compares the output level of the amplification signal for each Hall element output from the amplification unit 52 with the threshold level (0 V), and outputs a pulse signal corresponding to the comparison result for each Hall element.

  The output unit 70 compares an angle (hereinafter referred to as a calculation angle) φ calculated by the angle calculation unit 60 and a threshold angle (corresponding to the threshold value described in claim 1) φth, and the comparison result and the comparison unit 53. The relative rotation angle θ is 0 ≦ θ ≦ 90 °, 90 ° ≦ θ ≦ 180 °, 180 ° ≦ θ ≦ 270 °, and 270 ° ≦ θ ≦ 360 °. Determine if you are in a quadrant. Then, using the determination result and the calculation angle φ (corresponding to the calculation value described in claim 1) output from the angle calculation unit 60, the output angle corresponding to the relative rotation angle θ of 0 to 360 ° is set. The indicated signal Vo is output.

[Sensor chip structure]
The structure of the sensor chip 5 will be described. 4A and 4B are explanatory views schematically showing the structure of the sensor chip, in which FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along line AA in FIG. FIG. 5A is a plan view of the magnetoresistive element region E1 and the Hall element region E2, and FIG. 5B is an explanatory diagram showing the arrangement angles of the Hall elements H1 and H2. In each drawing, the dimensions of the hall elements H1 and H2 are drawn larger than the actual dimensions for easy understanding. Also, the shape of the magnetoresistive element is drawn larger than the actual size in order to make the formation direction of the element easy to understand.

  As shown in FIG. 4, the sensor chip 5 includes a silicon substrate 10, an insulating film 90 formed on the surface of the silicon substrate 10, AMR sensors M1 and M2 formed on the surface of the insulating film 90, silicon Hall elements H1 and H2 built in the substrate 10 are provided. The AMR sensor M1 includes magnetoresistive elements R1 to R4, and the AMR sensor M2 includes magnetoresistive elements R5 to R8. The Hall elements H1 and H2 are arranged so as to overlap below the magnetoresistive elements R1 to R8 with the insulating film 90 interposed therebetween.

  As shown in FIG. 5B, the Hall elements H1 and H2 are arranged such that the angle formed by the magnetic detection surfaces HP1 and HP2 of each magnetic detection unit HP is 90 °. That is, the Hall elements H1 and H2 are arranged so that the phase difference between the output signals is 90 °. If the line extending horizontally from the relative rotation center P1 of the sensor chip 5 toward the magnetoresistive element R2 is a reference line L3, and the position of the reference line L3 is a reference angle of 0 °, the Hall element H1 has its own magnetic detection surface. The angle α formed by HP1 and the reference line L3 is arranged to be 45 °.

  The Hall element H2 is also arranged so that the angle formed between its magnetic detection surface HP2 and the reference line L3 is 45 °. The magnetic detection surfaces HP1 and HP2 of the Hall elements H1 and H2 and the easy axis of magnetization of the magnetoresistive element R2 disposed at the reference angle of 0 ° form an angle of 45 °. That is, the Hall element H1 outputs a sin (θ + 45 °) signal whose phase is advanced by 45 ° with respect to the relative rotation angle θ, and the Hall element H2 is cos (θ + 45 °) whose phase is 90 ° different from that of the Hall element H1. ) Output the signal.

  Here, a region where the magnetoresistive elements R1 to R8 are disposed is referred to as a magnetoresistive element region E1, and a region where the Hall elements H1 and H2 are disposed is referred to as a Hall element region E2. FIG. 5A is created based on FIG. The magnetoresistive element region E1 has a quadrangular shape, and its area is substantially equal to the minimum area required for arranging the magnetoresistive elements R1 to R8. The hall element region E2 has a T-shape, and its area is substantially equal to the minimum area necessary for arranging the hall elements H1 and H2.

  As illustrated, the entire Hall element region E2 is overlapped below the magnetoresistive element region E1, and a part of the Hall element region E2 does not protrude from the end of the magnetoresistive element region E1. Further, the intersection of the diagonal lines L1 and L2 of the magnetoresistive element region E1 coincides with the relative rotation center P1 of the sensor chip 5. Further, the diagonal line L2 divides the T-shaped vertical region into two in the longitudinal direction in the Hall element region E2.

  That is, the relative rotation center P1 of the sensor chip 5 is located on the extension line of the relative rotation axis C1 (FIG. 2A) of the permanent magnet 2, and the relative rotation center P1 of the sensor chip 5 and the permanent magnet 2 are relative to each other. The center of rotation exists on the same axis. For this reason, even when the sensor chip 5 is relatively rotated around the relative rotation center P1 in a state where the permanent magnet 2 is not rotating, the relative rotation angle of the sensor chip 5 with respect to the permanent magnet 2 can be detected.

Since the sensor chip 5 has the above-described structure, the sensor chip 5 has a size (horizontal width) in the substrate surface direction as compared with the conventional rotation sensor in which the AMR sensor and the Hall element are arranged in the substrate surface direction of the semiconductor substrate. Can be small.
In addition, the magnetoresistive element region E1 and the hall element region E2 are overlapped in a direction corresponding to the relative rotation axis C1 (FIG. 2A) of the permanent magnet 2.

Accordingly, since the sensor chip 5 can be reduced in the direction of the rotation center of the permanent magnet 2, the space facing the rotation surface 2c of the permanent magnet 2 can be effectively utilized.
Further, since the area of the sensor chip 5 depends on the magnetoresistive element region E1, the area of the sensor chip 5 can be determined based on the area of the magnetoresistive element region E1.

(Structure of AMR sensor)
Next, the structure of the AMR sensors M1 and M2 will be described. FIG. 6 is a plan view schematically showing the structure of the AMR sensor M1. FIG. 7 is a plan view schematically showing the structure of the AMR sensor M2. FIG. 8 is an equivalent circuit of the AMR sensor M1, and FIG. 9 is an equivalent circuit of the AMR sensor M2. FIG. 10 is an explanatory diagram showing output signals of the AMR sensors M1, M2 and the Hall elements H1, H2.

The magnetoresistive elements R <b> 1 to R <b> 8 are formed in a shape obtained by folding a plurality of band-shaped regions, that is, in a meander shape (meandering shape). The resistance values of the magnetoresistive elements R <b> 1 to R <b> 8 mainly change depending on the strength and direction of the magnetic field parallel to the surface of the silicon substrate 10, and output a signal having a level corresponding to the resistance value. That is, the magnetoresistive elements R1 to R8 are elements that generate an anisotropic magnetoresistive effect.
In this embodiment, the magnetoresistive elements R1 to R8 are formed of a ferromagnetic metal thin film. As the ferromagnetic material, NiFe (permalloy), NiCo, or the like can be used. The ferromagnetic metal thin film can be formed by sputtering or vapor deposition.

  As shown in FIG. 6, the AMR sensor M1 includes four magnetoresistive elements R1 to R4. The magnetoresistive elements R <b> 1 to R <b> 4 are arranged so that the angle formed by the extending direction of the strip-shaped elements in the adjacent magnetoresistive elements is 90 °. In other words, the magnetoresistive elements R <b> 1 to R <b> 4 are arranged so that the current direction (magnetization easy axis) of the adjacent magnetoresistive elements forms an angle of 90 °. That is, each set of the magnetoresistive elements R1, R4 and R2, R3 is arranged such that the phase between the output signals is 90 ° different in each set.

  As shown in FIG. 8, the magnetoresistive elements R1 and R4 are electrically connected in series to form a half bridge circuit. An output terminal 31 for taking out the midpoint output Vout1 is electrically connected to the midpoint of the half bridge circuit. The magnetoresistive elements R2 and R3 are also electrically connected in series to form a half bridge circuit. An output terminal 32 for taking out the midpoint output Vout2 is electrically connected to the midpoint of the half bridge circuit.

  Both half bridge circuits are connected in parallel to form a full bridge circuit that outputs a cos 2θ signal. The full bridge circuit is electrically connected to a power supply terminal 30 for supplying power Vcc and a terminal 33 for electrically connecting to the ground G1. The magnetoresistive elements R1 and R2 facing each other in the full bridge circuit output (R0−ΔRcos2θ) signals, and the magnetoresistive elements R3 and R4 output (R0 + ΔRcos2θ) signals. Here, R0 is a resistance value of the magnetoresistive element in the absence of a magnetic field, and ΔR is a resistance value change amount.

Since each of the midpoint outputs Vout1 and Vout2 vibrates around Vcc / 2, it is possible to suppress an offset of the output waveform caused by a change in environmental temperature or the like.
The output terminals 31 and 32 are connected to a differential amplifier circuit (indicated by reference numeral 51a in FIG. 12), and the midpoint outputs Vout1 and Vout2 are differentially amplified. Therefore, the output amplitude of the AMR sensor M1 can be doubled compared to the case where the AMR sensor M1 is configured by one half bridge circuit, so that the magnetic detection sensitivity can be increased.

  As shown in FIG. 7, the AMR sensor M2 includes four magnetoresistive elements R5 to R8. The magnetoresistive elements R5 to R8 are arranged so that the angle formed by the extending direction of the strip-shaped elements in the adjacent magnetoresistive elements is 90 °. In other words, the magnetoresistive elements R5 to R8 are arranged so that the current direction (magnetization easy axis) of the adjacent magnetoresistive elements forms an angle of 90 °. That is, each set of magnetoresistive elements R5, R7 and R8, R6 is arranged such that the phase between the output signals is 90 ° different in each set.

  As shown in FIG. 9, the magnetoresistive elements R5 and R7 are electrically connected in series to form a half bridge circuit. An output terminal 37 for taking out the midpoint output Vout3 is electrically connected to the midpoint of the half bridge circuit. The magnetoresistive elements R8 and R6 are also electrically connected in series to form a half bridge circuit. An output terminal 38 for taking out the midpoint output Vout4 is electrically connected to the midpoint of the half bridge circuit.

  Both half-bridge circuits are connected in parallel to form a full-bridge circuit that outputs a sin 2θ signal. The full bridge circuit is electrically connected to a power supply terminal 36 for supplying power Vcc and a terminal 39 for electrically connecting to the ground G2. In the full bridge circuit, the magnetoresistive elements R5 and R6 facing each other output (R0 + ΔRsin2θ) signal, and the magnetoresistive elements R7 and R8 output (R0−ΔRsin2θ) signal.

Since each of the midpoint outputs Vout3 and Vout4 vibrates around Vcc / 2, it is possible to suppress an offset of the output waveform caused by a change in environmental temperature or the like.
The output terminals 37 and 38 are connected to a differential amplifier circuit (indicated by reference numeral 51b in FIG. 12), and the midpoint outputs Vout3 and Vout4 are differentially amplified. For this reason, the output amplitude of the AMR sensor M2 can be doubled as compared with the case where the AMR sensor M2 is configured by one half bridge circuit, so that the magnetic detection sensitivity can be increased.

  As shown in FIG. 4A, the magnetoresistive elements of the AMR sensors M1 and M2 are alternately arranged concentrically, and the magnetoresistive elements R1 to R4 of the adjacent AMR sensor M1 and the magnetoresistive elements of the AMR sensor M2. The resistance elements R5 to R8 are arranged so that the direction of current (magnetization easy axis) forms an angle of 45 °. The amount of change ΔR in the electrical resistance of the anisotropic magnetoresistive element is maximized when the angle between the direction of the current flowing in its own metal thin film (magnetization easy axis) and the direction of the magnetic field is 90 ° and 270 °. , 0 ° and 180 °.

  Therefore, as shown in FIG. 10, the AMR sensor M1 outputs a cos signal whose one wavelength is an electrical angle of 180 °, and the AMR sensor M2 has a phase difference of 45 ° from the AMR sensor M1 and one wavelength has an electrical angle. A 180 ° sin signal is output.

  As shown in FIG. 4B, the magnetoresistive elements R1 to R8 constituting the AMR sensors M1 and M2 are arranged on the surface layer portion of the silicon substrate 10 through the insulating film 90. The AMR sensors M1 and M2 mainly detect a change in magnetic flux density of the magnetic field B1 parallel to the magnetoresistive element region E1, that is, the silicon substrate 10. The Hall elements H1 and H2 are built in the silicon substrate 10, and are disposed below the magnetoresistive elements R1 to R8 through the insulating film 90. In this embodiment, each of the Hall elements H1 and H2 is a vertical Hall element having a CMOS (Complementary Metal Oxide Semiconductor) structure. The insulating film 90 is a silicon oxide film.

  The Hall elements H1 and H2 are arranged so that the phase difference between the output signals is 90 °. For this reason, as shown in FIG. 10, when the permanent magnet 2 rotates 360 °, the Hall element H1 outputs a sin signal having an electrical angle of 360 °, and the Hall element H2 has an electrical angle of 360 °. The cos signal is output.

(Hall element structure)
Next, the structure of the Hall elements H1 and H2 will be described. Since the Hall elements H1 and H2 have the same structure, the Hall element H2 will be described as an example here. 11A and 11B are explanatory diagrams of the Hall element H2, in which FIG. 11A is a plan view showing the Hall element H2 and a part of the periphery thereof, FIG. 11B is a cross-sectional view taken along the line AA in FIG. [FIG. 2] is a sectional view taken along line BB in FIG.

  The Hall element H2 has a high breakdown voltage CMOS transistor (HVCMOS) structure. The Hall element H2 includes a P-type (first conductivity type) silicon substrate (P-sub) 10 and an N-type (second conductivity type) semiconductor region formed in the depth direction from the surface layer portion of the silicon substrate 10. (Nwell) 91, a P-type (first conductivity type) diffusion layer (Pwell) 92 that surrounds the entire circumference of the semiconductor region 91, and a depth direction from the surface layer portion of the silicon substrate 10. P-type (first conductivity type) diffusion layers (Pwell) 93, 99 that divide a region from the surface layer portion to a predetermined depth into three semiconductor regions 91a, 91b, 91c, and respective surface layers of the semiconductor regions 91a, 91b, 91c Contact regions (N + diffusion layers (impurity diffusion regions)) 94 to 98 formed in the portion.

  Terminals S, V1, V2, G3, and G4 are electrically connected to the contact regions 94 to 98 through wiring. Terminals S, G3, and G4 are terminals for supplying a driving current, and terminals V1 and V2 are terminals for taking out a Hall voltage signal. That is, the contact regions 97 and 98 are current supply pairs, and the contact regions 95 and 96 are voltage output pairs. Therefore, the Hall elements H1 and H2 shown in FIG. 4A are arranged so that the lines connecting the current supply pairs are orthogonal to each other. Further, the lines connecting the voltage output pairs are arranged so as to be orthogonal to each other.

As shown in FIG. 11C, a region sandwiched between the contact regions 95 and 96 is a magnetic detection unit (hole plate) HP. Further, in the magnetic detection part HP, both surfaces parallel to the line connecting the contact regions 95 and 96 become the magnetic detection surface HP2, respectively. That is, the Hall element H2 outputs the Hall voltage signal corresponding to the magnetic field applied from the magnetic detection surface HP2 to the magnetic detection unit HP from the terminals V1 and V2.
As shown in FIG. 11B, when a constant drive current i is supplied from the terminal S to the terminal G3 and from the terminal S to the terminal G4, the drive current i is supplied from the contact region 94 to the magnetic detection unit HP, Then, it flows to the contact regions 97 and 98 through the semiconductor region 91 below the diffusion layers 93 and 98, respectively.

  That is, a drive current including a component perpendicular to the substrate surface (sensor chip surface) flows through the magnetic detection unit HP. For this reason, a magnetic field (for example, a magnetic field indicated by an arrow B1 in FIG. 11C) including a component parallel to the substrate surface (sensor chip surface) is applied to the magnetic detection unit HP in a state where the drive current flows. The Hall voltage VH corresponding to the magnetic field is generated between the terminals V1 and V2 by the Hall effect. The Hall voltage VH changes according to the angle formed by the magnetic detection surface HP2 and the direction of the magnetic field, that is, the incident angle of the magnetic field with respect to the magnetic detection surface HP2.

  As shown in FIGS. 2A and 3, the Hall elements H <b> 1 and H <b> 2 are arranged so that the magnetic detection surfaces HP <b> 1 and HP <b> 2 are perpendicular to the surface of the silicon substrate 10. 2 and a magnetic field B1 parallel to the surface of the silicon substrate 10 penetrates the magnetic detection surfaces HP1 and HP2 vertically. In the illustrated state, the magnetic field B1 penetrates perpendicularly to the magnetic detection surface HP2 of the Hall element H2, but when the permanent magnet 2 rotates 90 ° from the illustrated position, the magnetic field B1 changes to the magnetic detection surface of the Hall element H1. It penetrates perpendicularly to HP1. That is, the Hall elements H1 and H2 mainly detect changes in the magnetic flux density of the magnetic field B1 parallel to the surface of the silicon substrate 10.

  The N-type semiconductor region 91 is formed deeper than the N-type semiconductor region in the low breakdown voltage CMOS transistor structure, and accordingly, the P-type diffusion layers 92, 93, 98 are also P-type in the low breakdown voltage CMOS transistor structure. It is formed deeper than the diffusion layer. In this embodiment, the P-type diffusion layers 92, 93 and 98 are each formed to a depth approximately half that of the N-type semiconductor region 91.

Thus, since the Hall element H1 has the N-type semiconductor region 91 formed deeply, the carrier mobility is increased and the Hall effect can be increased, so that the Hall voltage VH can be increased. The detection sensitivity with respect to the magnetic field can be increased.
In addition, since the Hall element H1 is manufactured by a CMOS process, it is more cost-effective than a vertical Hall element manufactured by a bipolar process.

[Electrical configuration]
Next, the main electrical configuration of the rotation sensor 1 will be described. FIG. 12 is an explanatory diagram showing the main electrical configuration of the rotation sensor 1 in blocks, and corresponds to FIG. 13A and 13B are explanatory diagrams showing the output waveform of the Hall element, where FIG. 13A shows the output waveform of the Hall element H1, FIG. 13B shows the output waveform of the comparison circuit 53a, and FIG. 13C shows the output waveform of the Hall element H2. (D) is an output waveform of the comparison circuit 53b, (e) is an output waveform of the calculation angle output from the angle calculation unit 60, and (f) is a comparison result between the calculation angle φ and the threshold angle φth shown in (e). The waveform shown, (g), is the output waveform of the output logic circuit 71.

(Amplifier 51 and angle calculator 60)
The amplifier 51 includes a differential amplifier circuit 51a that differentially amplifies the output signal sin2θ of the AMR sensor M1, and a differential amplifier circuit 51b that differentially amplifies the output signal cos2θ of the AMR sensor M2. The angle calculation unit 60 is a tracking loop type digital angle conversion circuit, and includes multiplication circuits 61 and 62, a subtraction circuit 63, a window comparator 64, an up / down counter 65, a cos 2φ output circuit 66, and a D / A converter. (DAC) 67, a sin 2φ output circuit 68, and a D / A converter (DAC) 69.

  The cos 2φ output circuit 66 outputs data cos 2φ corresponding to the digital calculation angle φ output from the up / down counter 65. For example, the cos 2φ output circuit 66 includes a ROM that stores a table in which the calculation angle φ and the data cos 2φ are associated with each other. The cos 2φ output circuit 66 reads out and outputs the data cos 2φ associated with the calculation angle φ. The D / A converter 67 converts the data cos2φ output from the cos2φ output circuit 66 into an analog signal cos2φ.

  The sin 2φ output circuit 68 outputs data sin 2φ corresponding to the digital calculation angle φ output from the up / down counter 65. For example, the sin2φ output circuit 68 includes a ROM that stores a table in which the calculation angle φ and the data sin2φ are associated with each other. The data sin2φ associated with the calculation angle φ is read from the ROM and output. The D / A converter 69 converts the data sin2φ output from the sin2φ output circuit 68 into an analog signal sin2φ.

  Multiplier circuit 61 multiplies signal sin2θ output from differential amplifier circuit 51a and signal cos2φ output from cos2φ output circuit 66, and outputs signal sin2θcos2φ. The multiplier circuit 62 multiplies the signal cos2θ output from the differential amplifier circuit 51b and the signal sin2φ output from the sin2φ output circuit 68, and outputs a signal cos2θsin2φ.

  The subtraction circuit 63 subtracts the signal cos2θsin2φ output from the multiplication circuit 62 from the signal sin2θcos2φ output from the multiplication circuit 61, and calculates sin (2θ-2φ). That is, the cos 2φ output circuit 66, the D / A converter 67, the sin 2φ output circuit 68, the D / A converter 69, the multiplication circuits 61 and 62, and the subtraction circuit 63 calculate sin 2θ cos 2φ−cos 2θ sin 2φ = sin (2θ−2φ). , A circuit for obtaining a control deviation ε = sin (2θ−2φ).

  The window comparator 64 compares sin (2θ-2φ) output from the subtraction circuit 63 with two threshold values having different sizes, and when sin (2θ-2φ) is larger than the larger threshold value, An up signal (for example, a positive pulse signal) for counting up / down counter 65 is output. Further, when the sin (2θ−2φ) output from the subtracting circuit 63 is smaller than the smaller threshold value, the window comparator 64 outputs a down signal (for example, negative polarity) for counting down the up / down counter 65 in the next stage. Output pulse signal).

  The up / down counter 65 adds one count value each time an up signal is input from the window comparator 64 (for example, every time the number of positive pulses is counted), and every time a down signal is input from the window comparator 64. One count value is subtracted (for example, every time the number of negative pulses is counted). The up / down counter 65 outputs the count value as the calculation angle φ to the cos 2 φ output circuit 66 and the sin 2φ output circuit 68.

  The count value output from the up / down counter 65 is latched in the output logic circuit 71. The angle calculation unit 60 repeats the calculation of the control deviation ε by feeding back the calculation angle φ until the absolute value of the control deviation ε = sin (2θ−2φ) is equal to or less than the threshold, for example, ε = 0.

(Amplification unit 52 and comparison unit 53)
The amplification unit 52 includes an amplification circuit 52a that amplifies a sin (θ + 45 °) signal output from the Hall element H1, and an amplification circuit 52b that amplifies a cos (θ + 45 °) signal output from the Hall element H2. The comparison unit 53 compares the signal level output from the amplifier circuit 52a with the threshold level, outputs a first pulse signal corresponding to the comparison result, and the signal level output from the amplifier circuit 52b. A comparison circuit 53b that compares the threshold level and outputs a second pulse signal corresponding to the comparison result is provided. Comparison circuits 53a and 53b can also be referred to as pulsing circuits.

  In this embodiment, 0 V is set as the threshold level, and each comparison circuit outputs a high level (H) signal when the input signal is positive and a low level (L) signal when the input signal is negative. Output each. For this reason, as shown in FIG. 13B, the comparison circuit 53a maintains a high level when the relative rotation angle θ is 0 to 180 ° and low when the relative rotation angle θ is 180 to 360 °. A first pulse signal VH1 that maintains the level is output. As shown in FIG. 13D, the comparison circuit 53b maintains a high level when the relative rotation angle θ is 90 to 270 °, and maintains a low level when the relative rotation angle θ is 270 to 90 °. The second pulse signal VH2 is output. First and second pulse signals VH1 and VH2 output from comparison circuits 53a and 53b are output to output logic circuit 71.

(Output part)
The output unit 70 includes an output logic circuit 71. 14A shows the signal levels (high level (H) and low level (L)) of the first and second pulse signals VH1 and VH2 output from the comparison circuits 53a and 53b, the calculation angle φ, and the threshold angle. It is explanatory drawing which shows the relationship between the comparison result (high level (H) and low level (L)) with (phi) th, and the angle range of relative rotation angle (theta). In addition, the code | symbol (A)-(H) in the table | surface shown to Fig.14 (a) respond | corresponds to the code | symbol AH described in FIG.

  The output logic circuit 71 outputs the latched count value as the calculation angle φ when the control deviation ε becomes equal to or less than the threshold value. When this calculation angle φ is represented by a signal, as shown in FIG. 13E, a signal having an electrical angle of one wavelength that is maximum when the relative rotation angle θ is 0 ° and 180 ° (an example shown in the figure). Then sawtooth wave).

  Subsequently, the output logic circuit 71 compares the calculation angle φ, which is the digital value, with the threshold angle φth, which is also the digital value, in the digital domain, and outputs the comparison result. In this embodiment, the threshold angle φth is set to ½ of the maximum value of the calculation angle φ. As shown in FIG. 13F, when the calculation angle φ is greater than or equal to the threshold angle φth, H), and the pulse signal VM1 that changes to the low level (L) when the calculation angle φ is less than the threshold angle φth is generated as a comparison result.

  The output logic circuit 71 determines the signal levels of the first and second pulse signals VH1 and VH2 and the signal level of the pulse signal VM1. The output logic circuit 71 uses the determination result VMt of each of the first and second pulse signals VH1 and VH2 and the determination result VMt of the signal level of the pulse signal VM1, and the relative rotation angle θ is 0 to 360. It is determined which quadrant (angle range) of the four quadrants obtained by dividing the relative rotation angle θ of 90 ° in units of 90 °.

  By the way, when the output signals of the Hall elements H1 and H2 are affected by voltage offset or random noise, the voltage near the point where the phase is switched by 180 ° may become unstable. For this reason, such an unstable region (the hatched region in FIG. 13) indicates which angle range the relative rotation angle is when the relative rotation angle of 0 to 360 ° is divided into 90 ° angular ranges. In order to increase the detection accuracy, it is desirable not to use it as an element for determining whether or not to enter. In this embodiment, a range of 45 ° from both points where the phases of the first and second pulse signals are switched by 180 ° (a total of 90 ° for both ends) is considered as an unstable region. On the other hand, since the pulse signal VM1 is created based on the calculation angle φ that is a digital value, the pulse signal VM1 is stable because it is not affected by a voltage offset or random noise.

  Therefore, in this embodiment, the first and second pulse signals VH1, VH2 and the pulse signal VM1 are configured to have a phase difference of 45 °, and the unstable region is compensated by the pulse signal VM1. Can be done. As shown in FIG. 13, the 45 ° range of the region where the first and second pulse signals are unstable corresponds to the pulse width of the first and second pulse signals. In the region, the signal level of the pulse signal VM1 can be used for determination.

  As shown in FIG. 14, in the output logic circuit 71, when VH1 is high level (H) and VMt is low level (L), the relative rotation angle θ is a quadrant (0 ° ≦ θ <90 °) ( It is determined that it exists in the angle range. When VH2 is at a high level (H) and VMt is also at a high level (H), it is determined that the relative rotation angle θ exists in a quadrant of 90 ° ≦ θ <180 °. When VH1 is at a low level (L) and VMt is also at a low level (L), it is determined that the relative rotation angle θ exists in a quadrant of 180 ° ≦ θ <270 °. When VH2 is at a high level (H) and VMt is also at a high level (H), it is determined that the relative rotation angle θ is in a quadrant of 270 ° ≦ θ <360 °.

Thus, since the combinations of the determination results of VH1, VH2, and VMt are all different in each quadrant, it is possible to accurately determine the quadrant (angle range) where the relative rotation angle θ exists. In particular, since the MRE has high sensitivity and the calculation angle calculated based on the output signal is a digital value, the quadrant can be determined with high accuracy (in the range of 1 LSB).
In addition, since a determination result that may become unstable is not used among VH1 and VH2, even if a voltage offset or random noise occurs, the quadrant (angle range) in which the relative rotation angle θ exists is further increased. A more accurate determination can be made.
As shown in FIG. 13E, there are two cases where the voltage VM becomes 0V, when the relative rotation angle θ is 0 ° and when it is 180 °. Refer to the combination of the above determination results. By doing so, it is possible to accurately determine whether the relative rotation angle θ is 0 ° or 180 °.

  That is, when VH1 is high level (H) and VMt is low level (L), the relative rotation angle θ is determined to be 0 °. When VH1 is low level (L) and VMt is also low level (L), it is determined that the relative rotation angle θ is 180 °. Thus, even when the permanent magnet 2 starts rotating from a position where the voltage VM becomes 0 V, whether the relative rotation angle θ when the rotation starts is 0 ° or 180 °. Can be determined.

  Therefore, the output logic circuit 71 can output an accurate calculation angle φ corresponding to the relative rotation angle θ. Further, the output logic circuit 71 converts the calculation angle φ into an analog signal having a cycle of 360 °, and the voltage Vo corresponds to the change in the relative rotation angle θ from 0 ° to 360 ° as shown in FIG. It is possible to output an angle signal having a period of 360 ° in which the angle rises linearly.

  In addition, comparing the Hall element and the magnetoresistive element with the sensitivity of the magnetic field, the magnetoresistive element is larger, so the signal obtained by the magnetoresistive element is used as a linear output signal, thereby configuring a highly accurate rotation sensor. it can. In addition, since the permanent magnet can be used even when the strength (magnitude of the magnetic field) is small, the cost of the permanent magnet can be reduced.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to the drawings.
15A and 15B are explanatory views schematically showing the structure of a sensor chip provided in the rotation sensor of this embodiment, wherein FIG. 15A is a plan view and FIG. 15B is a cross-sectional view taken along the line AA in FIG. It is. FIG. 16 is an explanatory diagram showing the main electrical configuration of the rotation sensor 1 of this embodiment in blocks. FIG. 17 is an explanatory diagram showing an output waveform of the Hall element or the like in this embodiment, and corresponds to FIG. The rotation sensor according to this embodiment has the same configuration as the rotation sensor according to the first embodiment except for the arrangement positions of the Hall elements H1 and H2, and therefore the same components are denoted by the same reference numerals and description thereof is omitted. To do.

As shown in FIG. 15, the Hall elements H <b> 1 and H <b> 2 are arranged at positions rotated 90 ° in the left direction as compared with the Hall elements provided in the rotation sensor 1 of the first embodiment. That is, the Hall elements H1 and H2 are arranged so that the phase is delayed by 90 ° compared to the output signal of the Hall element of the first embodiment.
Therefore, the Hall element H1 outputs a sin (θ−45 °) signal whose phase is delayed by 45 ° with respect to the relative rotation angle θ, and the Hall element H2 has a cos that is 90 ° out of phase with the Hall element H1. (Θ−45 °) signal is output.

As shown in FIG. 16, the main electrical configuration of the rotation sensor is the same as that of the first embodiment shown in FIG. 12 except that the output signals of the Hall elements H1 and H2 are different.
FIG. 14B is an explanatory diagram corresponding to FIG. 14A in the first embodiment. As shown in the figure, the first and second pulse signals VH1 and VH2 are the same as those in the first embodiment except that the combinations of the signal levels are different.

  As described above, the rotation sensor according to the second embodiment is the same as the rotation sensor 1 of the first embodiment except that the phase of the output signals of the Hall elements H1 and H2 is delayed by 45 ° with respect to the relative rotation angle θ. Since it is the same structure, there can exist the same effect as 1st Embodiment.

<Third Embodiment>
Next, a third embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 18 (a), the Hall elements H1 and H2 are arranged at a position rotated by 45 ° in the left direction from the arrangement position of the first embodiment, and the reference angle 0 ° is also from the position of the first embodiment. It can also be set at a position rotated 45 ° in the left direction of the drawing. Also in this configuration, as in the first embodiment, the output signals of the Hall elements H1 and H2 are sin (θ + 45 °) and cos (θ + 45 °), respectively. Therefore, the same effect as in the first embodiment can be obtained. Can play.

  Further, as shown in FIG. 18B, the Hall elements H1 and H2 are arranged at a position rotated by 45 ° in the left direction of the drawing from the arrangement position of the first embodiment, and the reference angle 0 ° is the same as that of the first embodiment. It can also be set to a position rotated 45 ° from the position to the right in the drawing. Also in this configuration, as in the second embodiment, the output signals of the Hall elements H1 and H2 are sin (θ−45 °) and cos (θ−45 °), respectively. The same effect can be achieved.

  That is, each output signal of the Hall elements H1 and H2 may be configured to have a phase difference of ± 45 ° with respect to the relative rotation angle θ. For that purpose, as in the first and second embodiments, the Hall elements A method of devising the arrangement positions of the elements H1 and H2 may be used, or a method of devising the set position of the reference angle 0 ° electrically as in the third embodiment may be used.

<Fourth embodiment>
Next, a fourth embodiment of the invention will be described with reference to the drawings.
As shown in FIG. 19A, one Hall element H <b> 1 is arranged so that the center thereof coincides with the relative rotation center P <b> 1 of the sensor chip 5. The other Hall element is composed of two Hall elements H2-1 and H2-2, and is disposed on both sides of the Hall element H1. The Hall elements H2-1 and H2-2 are formed in the same size and shape, and generate the same Hall voltage when magnetic fields having the same intensity are applied at the same incident angle.

  The Hall elements H2-1 and H2-2 are arranged such that a line L5 orthogonal to the line L4 passing through the relative rotation center P1 passes through the center of the Hall elements H2-1 and H2-2, and are arranged at the same distance from the relative rotation center P1. . Further, the magnetic detection surface of the Hall element H1 and the magnetic detection surfaces of the Hall elements H2-1 and H2-2 form an angle of 90 °.

  The output signals of the Hall elements H2-1 and H2-2 are added and output as one output signal, which is input to the comparison circuit 53b (FIG. 12). That is, by adding the output signals, the center of the area formed by the Hall elements H2-1 and H2-2 is made to coincide with the relative rotation center P1 in a pseudo manner.

  As described above, since the center of each Hall element can coincide with the relative rotation center P1, the magnetic field B1 generated from the permanent magnet 2 is not biased due to the arrangement position of the Hall element. Therefore, each Hall element outputs a signal with a well-formed shape according to a change in the relative rotation angle θ, so that the determination accuracy of the quadrant of the relative rotation angle θ can be increased.

  As shown in FIG. 19B, the Hall elements H1-1 and H1-2 and the Hall elements H2-1 and H2-2 are formed in the same size and shape, and the same incident magnetic field has the same incidence. When applied at an angle, the same Hall voltage is generated. The Hall elements H1-1 and H1-2 are arranged on a line L4 passing through the relative rotation center P1, and the Hall elements H2-1 and H2-2 pass through the relative rotation center P1 and are orthogonal to the line L4. Is arranged on the line L5. The Hall elements H1-1 and H1-2 are arranged so that the line L4 passes through the center of the Hall elements H1-1 and H1-2, and the Hall elements H2-1 and H2-2 are arranged so that the line L5 passes through the center of the Hall element H1-1 and H1-2. Has been.

  Furthermore, the Hall elements H1-1 and H1-2 are arranged at the same distance from the relative rotation center P1, and the Hall elements H2-1 and H2-2 are also arranged at the same distance from the relative rotation center P1. . Further, the distance from the relative rotation center P1 is the same in all four Hall elements. The magnetic detection surfaces of the Hall elements H1-1 and H1-2 and the magnetic detection surfaces of the Hall elements H2-1 and H2-2 form an angle of 90 °.

  The output signals of the Hall elements H1-1 and H1-2 are added and output as one output signal, which is input to the comparison circuit 53a (FIG. 12). That is, by adding the output signals, the center of the area composed of the Hall elements H1-1 and H1-2 is made to coincide with the relative rotation center P1 in a pseudo manner. The output signals of the Hall elements H2-1 and H2-2 are added and output as one output signal, which is input to the comparison circuit 53b (FIG. 12). That is, by adding the output signals, the center of the area formed by the Hall elements H2-1 and H2-2 is made to coincide with the relative rotation center P1 in a pseudo manner.

  As described above, since the center of each Hall element can coincide with the relative rotation center P1, the magnetic field B1 generated from the permanent magnet 2 is not biased due to the arrangement position of the Hall element. Therefore, each Hall element outputs a signal with a well-formed shape according to a change in the relative rotation angle θ, so that the determination accuracy of the quadrant of the relative rotation angle θ can be increased.

<Fifth Embodiment>
Next explained is the fifth embodiment of the invention. 20A and 20B are longitudinal sectional views of a sensor chip and a permanent magnet provided in the rotation sensor of this embodiment.

  The rotation sensor includes a sensor chip 5 that is disposed with the front and back surfaces of the sensor chip 5 provided in the rotation sensor 1 of the first embodiment reversed. That is, the Hall element region E2 is disposed on the side facing the relative rotation surface 2c of the permanent magnet 2, and the magnetoresistive element region E1 is disposed below the Hall element region E2. Also in the sensor chip 5 having such a structure, as shown in the figure, a magnetic field B1 generated from the permanent magnet 2 and parallel to the surface 5a of the sensor chip 5 is applied to the Hall elements H1 and H2 and the AMR sensors M1 and M2. Therefore, the relative rotation angle θ of the permanent magnet 2 can be detected.

<Sixth Embodiment>
Next, a sixth embodiment of the invention will be described. FIG. 21 is an explanatory view showing an example of the usage state of the sensor chip provided in the rotation sensor of this embodiment, where (a) is a plan view and (b) is a cross-sectional view taken along line AA in (a). It is.

  The magnet rotor 6 has a rotor body 6a. In this embodiment, the rotor body 6a is formed in a bottomed cylindrical shape. N-pole permanent magnets 2a and S-pole permanent magnets 2b are attached to the inner wall surface of the outer peripheral wall erected in the circumferential direction of the rotor body 6a. The tip of the rotating shaft 3 is attached to the center of the bottom of the rotating body 6. When the rotating shaft 3 rotates about the relative rotation axis C1, the rotating body 6 also rotates in the same direction as the rotating shaft 3 about the relative rotation axis C1.

  A sensor chip 5 is disposed between the permanent magnets 2a and 2b facing each other and spaced apart from the permanent magnets 2a and 2b at the center of relative rotation of the rotor body 6a. The sensor chip 5 is arranged so that the magnetic field B1 generated between the permanent magnets 2a and 2b is parallel to the surface 5a of the sensor chip 5. That is, the magnetic field B1 is arranged so that the direction of the magnetic field B1 is parallel to the AMR sensors M1 and M2 and perpendicular to the magnetic detection surfaces HP1 and HP2 of the Hall elements H1 and H2. The sensor chip 5 is supported by a support member (not shown), and is fixed so that the arrangement position does not change.

  Since the sensor chip 5 arranged as described above can detect a change in the magnetic flux density of the magnetic field B1 parallel to the surface thereof, the relative rotation angle θ of the rotor body 6a can be detected. Further, since the sensor chip 5 has a structure in which the magnetoresistive element region E1 and the hall element region E2 are overlapped, the sensor chip 5 can be reduced in size in the plane direction. Therefore, the diameter of the rotor body 6a can be reduced. In addition, as shown in FIG. 20, it can also arrange | position with the front and back of the sensor chip 5 reversed.

[Example of change]
Next, a modified example of the above-described sixth embodiment will be described. FIG. 22 is a plan view of a sensor chip and a rotator provided in the rotation sensor of the modified example. 22A and 22B, the cross-sectional structure of the sensor chip 5 is the same as the structure shown in FIG. In addition, as shown in FIG. 20, the front and back surfaces of the sensor chip 5 can be reversed.

  As shown in FIG. 22 (a), two pairs of permanent magnets each having an N-pole permanent magnet 2a and an S-pole permanent magnet 2b arranged opposite to each other are attached to the inner wall surface of the rotor body 6a. A sensor chip 5 is arranged at the relative rotation center of the rotor body 6a. In this way, even when there are two pairs of N and S poles, the relative rotation angle θ of the rotor body 6a is detected by arranging the sensor chip 5 so that the magnetic field thereof is parallel to the magnetoresistive element region E1. be able to.

  Further, as shown in FIG. 22 (b), three or more pairs of permanent magnets having N pole permanent magnets 2a and S pole permanent magnets 2b arranged opposite to each other are attached to the inner wall surface of the rotor body 6a. ing. That is, a multipolar permanent magnet is attached. Thus, even when there are three or more pairs of N and S poles, the relative rotation angle θ of the rotor body 6a is detected by arranging the sensor chip 5 so that the magnetic field thereof is parallel to the magnetoresistive element region E1. can do.

<Seventh embodiment>
Next explained is the seventh embodiment of the invention. FIG. 23 is a cross-sectional view showing an example of a usage state of a sensor chip provided in the rotation sensor of this embodiment. 23A and 23B, the cross-sectional structure of the sensor chip 5 is the same as that shown in FIG. In addition, as shown in FIG. 20, the front and back surfaces of the sensor chip 5 can be reversed. The structure and shape of the permanent magnet 2 are the same as those of the permanent magnet shown in FIG.

  As shown in FIG. 23A, the sensor chip 5 is disposed on the side of the rotating peripheral surface 2 d of the permanent magnet 2. Even with such an arrangement, since the magnetic field B1 parallel to the magnetoresistive element region E1 of the sensor chip 5 can be detected from the permanent magnet 2, the relative rotation angle θ of the permanent magnet 2 can be detected. Therefore, even if the sensor chip 5 cannot be disposed in the space facing the relative rotation surface 2c of the permanent magnet 2, the sensor chip 5 is placed on the side of the rotation circumferential surface 2d of the permanent magnet 2 as shown in the figure. The relative rotation angle θ of the permanent magnet 2 can be detected.

  As shown in FIG. 23B, the sensor chip 5 is disposed at a position facing the relative rotation surface 2 c of the permanent magnet 2 and on the side of the rotation shaft 3. Even with such an arrangement, since the magnetic field B1 parallel to the magnetoresistive element region E1 of the sensor chip 5 can be detected from the permanent magnet 2, the relative rotation angle θ of the permanent magnet 2 can be detected. Accordingly, even when the sensor chip 5 cannot be disposed on the side of the rotating peripheral surface 2d of the permanent magnet 2, the position where the sensor chip 5 faces the relative rotating surface 2c of the permanent magnet 2 as shown in the drawing. In this case, the relative rotation angle θ of the permanent magnet 2 can be detected by arranging it on the side of the rotating shaft 3.

<Eighth Embodiment>
Next, an eighth embodiment of the invention will be described. FIG. 24 is an explanatory view schematically showing the structure of a sensor chip provided in the rotation sensor of this embodiment, where (a) is a plan view and (b) is a cross-sectional view taken along line AA in (a). It is.

  The AMR sensor M1 has a half bridge circuit in which magnetoresistive elements R2 and R3 are connected in series. The AMR sensor M2 has a half bridge circuit in which magnetoresistive elements R6 and R8 are connected in series. The magnetoresistive elements R2 and R3 are arranged such that the phase difference between the output signals from the magnetoresistive elements is 90 °. The magnetoresistive elements R6 and R8 are also arranged so that the phase difference between the output signals from the magnetoresistive elements is 90 °. The magnetoresistive elements R2, R3, R6, and R8 are alternately arranged so that the phase difference between the output signal from the output terminal 32 of the AMR sensor M1 and the output signal from the output terminal 38 of the AMR sensor M2 is 45 °. Has been.

  Thus, by configuring the AMR sensors M1 and M2 with half bridge circuits, respectively, the area of the magnetoresistive element region E1 can be reduced, so that the sensor chip 5 can be reduced in size.

<Ninth Embodiment>
Next, a ninth embodiment of the invention will be described. FIG. 25 is an equivalent circuit of the AMR sensor provided in the rotation sensor of this embodiment.

  The magnetoresistive element constituting the AMR sensor M1 is only one R3, and the magnetoresistive element constituting the AMR sensor M2 is only one R8. The magnetoresistive elements R3 and R8 are arranged such that a phase difference of 45 ° is generated between output signals of the magnetoresistive elements. A constant current source 72 is connected to each of the magnetoresistive elements R3 and R8.

  Thus, by configuring each of the AMR sensors M1, M2 with only one magnetoresistive element, the area of the magnetoresistive element region E1 can be reduced, so that the sensor chip 5 can be reduced in size.

<Tenth embodiment>
Next, a tenth embodiment of the invention is described. FIG. 26 is an explanatory view schematically showing the structure of a sensor chip provided in the rotation sensor of this embodiment, where (a) is a plan view and (b) is a cross-sectional view taken along the line AA in (a). It is. FIG. 27 is an explanatory diagram showing in block form a part of the main electrical configuration of the rotation sensor.

  As shown in FIG. 26A, the Hall elements H1 and H2 are arranged such that a phase difference of 45 ° is generated between output signals from the Hall elements. The Hall element H1 outputs a sin θ signal whose one wavelength is an electrical angle of 360 ° with respect to the relative rotation angle θ. The Hall element H2 outputs a signal having a phase difference of 45 ° with respect to the output signal of the Hall element H1, that is, a sin (45 ° + θ) signal with one wavelength having an electrical angle of 360 °.

As shown in FIG. 27, a sin θ cos θ calculation unit 54 is electrically connected between the amplification unit 52 and the comparison unit 53. The sin θ cos θ calculation unit 54 uses the sin θ signal output from the amplification unit 52 and the sin (45 ° + θ) signal, and extracts the sin θ signal and the cos θ signal. That is, the sin θ cos θ calculation unit 54 converts the sin (45 ° + θ) signal output from the amplification unit 52 into a (sin θ + cos θ) / 2 ^1/2 signal, and uses this signal and the sin θ signal, The cos θ signal is taken out.

<Eleventh embodiment>
Next, an eleventh embodiment of the present invention will be described. FIG. 28 is an explanatory diagram showing in block form the configuration of the angle calculator 60 provided in the rotation sensor of this embodiment.

The angle calculation unit 60 performs an arctangent calculation of sin2θ and cos2θ based on the sin2θ signal output from the AMR sensor M1 and the cos2θ signal output from the AMR sensor M2, and the calculation angle φ = tan ^−1. It has a function of obtaining (sin 2θ / cos 2θ). The angle calculation unit 60 includes A / D converters 81 and 82, a DSP (Digital Signal Processor) 83, a D / A converter 84, and an amplifier circuit 85. The DSP 83 includes an averaging unit 83a, a temperature characteristic correcting unit 83b, and an angle calculating unit 83c.

  The sin 2θ signal output from the AMR sensor M 1 is converted into a digital value at a predetermined sampling interval by the A / D converter 81, and the cos 2θ signal output from the AMR sensor M 2 is predetermined by the A / D converter 81. Are converted into digital values at a sampling interval of. The sampling interval is determined by the sampling frequency generated based on the clock frequency of the clock signal supplied from the CPU (not shown) to the angle calculator 60.

  The averaging unit 83a of the DSP 83 calculates an average value of the digital values of sin 2θ converted by the A / D converter 81 during a predetermined sampling period, and is converted by the A / D converter 82 during a predetermined sampling period. The average value of the digital values of cos 2θ is calculated. Since the characteristics of the permanent magnet 2 and the rotation sensor 1 change according to changes in the environmental temperature, an error occurs in the calculation angle. Therefore, the temperature characteristic correction unit 83b performs correction based on the temperature characteristics of the permanent magnet 2 and the rotation sensor 1 for each average value calculated by the averaging unit 83a, thereby reducing the error of the calculation angle.

  The angle calculation unit 83c calculates the calculation angle φ by performing an arctangent calculation of sin2θ and cos2θ using the digital values sin2θ and cos2θ corrected by the temperature characteristic correction unit 83b. The calculation angle φ output from the angle calculation unit 83c is converted into an analog signal by the D / A converter 84, amplified by the amplifier circuit 85, and output as a signal indicating the calculation angle φ.

<Twelfth embodiment>
Next, a twelfth embodiment of the invention is described. FIG. 29 is an explanatory diagram showing the main electrical configuration of the rotation sensor of this embodiment in blocks.

The detection circuit 50 includes correction units 55 and 56. The correction unit 55 corrects the amplitude difference, offset, and initial phase error between the sin 2θ signal and the cos 2θ signal output from the amplification unit 51. The correction unit 56 corrects the amplitude difference, offset, and initial phase error between the sin θ signal and the cos θ signal output from the amplification unit 52.
As described above, the rotation sensor of this embodiment can correct the amplitude difference, offset, and initial phase error of the signals output from the AMR sensors M1 and M2 and the Hall elements H1 and H2. Detection accuracy can be increased.

<Other embodiments>
(1) In 1st Embodiment, without providing the output logic circuit 71 on the same board | substrate as the angle calculating part 60, it provides in the side (for example, ECU side with which the vehicle was equipped) which uses the output of the output logic circuit 71. You can also.
(2) The detection circuit 50 may be formed on the silicon substrate 10 so that the sensor chip 5 and the detection circuit 50 can be integrated.
(3) The number of pulse outputs from the Hall element H1 or H2 can be counted to detect multiple rotations (360 ° or more).

(4) Instead of the silicon substrate 10, a substrate formed of a compound semiconductor such as GaAs, InAs, or InSb can also be used.
(5) A member coated with magnetic ink may be used instead of the permanent magnet. A member magnetized on the surface of the conductive member can also be used.
(6) The horizontal Hall element can be used by being superposed on the magnetoresistive element region so that the magnetic detection surface is perpendicular to the magnetoresistive element.
(7) The output logic circuit 71 may output a digital value indicating an output angle corresponding to the relative rotation angle θ of 0 to 360 °.
(8) Each output of the comparison circuits 53a and 53b may be A / D converted, the converted digital value and the digital threshold value may be compared, and the comparison result may be output.
(9) The calculation angle φ output by the up / down counter 65 may be compared with a digital threshold value, and the comparison result may be output. According to this configuration, there is no need to create the pulse signal VM1.

  Application of the rotation sensor 1 according to the present invention is not limited as long as the detection target rotates relatively. For example, a crank angle sensor that detects a crank angle of a crankshaft provided in an internal combustion engine, a cam angle sensor that detects a cam angle of a camshaft, a steering angle sensor that detects a steering angle of a steering device provided in a vehicle, a vehicle The present invention can be applied to a sensor that detects the rotation angle of various motors provided in the motor. The present invention can also be applied to a sensor that detects the angle of a joint provided in a robot.

1 .... rotation sensor, 2 .... magnet (magnet generator), 5 .... sensor chip,
10 .. Silicon substrate, E1, .. magnetoresistive element region, E2, .. Hall element region,
H1, H2 ... Hall elements, M1, M2 ... AMR sensors,
R1-R8 .. Magnetoresistive element.

Claims (26)

A magnetoresistive element that generates a magnetoresistive effect by the magnetism generated from the magnetism generating unit; and a Hall element that generates a Hall effect by the magnetism, and using the output signals from the magnetoresistive element and the Hall element, In the rotation sensor that detects the relative rotation angle with respect to the magnetism generation unit
A magnetoresistive element region in which a plurality of magnetoresistive elements are arranged so as to have a phase difference between the output signals of the respective magnetoresistive elements, and a plurality of hall elements are arranged so that a phase difference is produced between the output signals of the respective hall elements. And a sensor chip in which at least a part of the magnetoresistive element region and the hall element region are overlapped with each other,
A comparison unit that compares each output level of each Hall element with a threshold level and outputs a comparison result for each Hall element;
An angle calculator that calculates an angle corresponding to the relative rotation angle using each output signal of each magnetoresistive element;
An output unit that compares the calculated value calculated by the angle calculation unit with a threshold, uses the comparison result and the comparison result of the comparison unit, and outputs a signal corresponding to the relative rotation angle;
A rotation sensor comprising:   The rotation sensor according to claim 1, wherein substantially the entire area of the hall element area is overlapped with the magnetoresistive element area.   3. The rotation sensor according to claim 1, wherein the magnetoresistive element region and the Hall element region are overlapped in a direction corresponding to a relative rotation axis direction of the magnetism generating unit.   The rotation sensor according to any one of claims 1 to 3, wherein the magnetoresistive element region and the Hall element region are disposed substantially parallel to a relative rotation surface of the magnetism generating unit.   The magnetoresistive element region is disposed on the front surface side of the sensor chip, and the Hall element region is disposed on the back surface side of the sensor chip, so that the surface of the sensor chip faces the relative rotation surface of the magnetism generating unit. The rotation sensor according to any one of claims 1 to 4, wherein the rotation sensor is arranged in a vertical direction.   The magnetoresistive element region is disposed on the front surface side of the sensor chip, and the Hall element region is disposed on the back surface side of the sensor chip, so that the back surface of the sensor chip faces the relative rotation surface of the magnetism generator. The rotation sensor according to any one of claims 1 to 4, wherein the rotation sensor is arranged in a vertical direction.   The rotation sensor according to any one of claims 1 to 6, wherein the magnetism generating unit has different magnetic poles divided in a radial direction of a relative rotation surface thereof.   The rotation sensor according to any one of claims 1 to 6, wherein the magnetism generator is a different magnetic pole disposed in a circumferential direction of a rotating body that rotates relative to the magnet.   The rotation sensor according to claim 8, wherein the sensor chip is disposed between the different magnetic poles.   The rotation sensor according to any one of claims 1 to 9, wherein the magnetism generator is multipolar.   2. The magnetoresistive element and the hall element are arranged so as to mainly detect a change in magnetic flux density of a magnetic field parallel to the magnetoresistive element area and the hall element area. The rotation sensor according to claim 10.   12. The hall elements according to claim 1, wherein the hall elements are arranged so that a phase difference of 90 [deg.] Occurs between output signals of adjacent hall elements. Rotation sensor.   Each of the magnetoresistive elements is arranged so that a phase difference of 45 ° is generated between output signals of the magnetoresistive elements adjacent to each other. The rotation sensor described.   The first and second half bridge circuits in which the magnetoresistive elements are half-bridge connected so that a 90 ° phase difference is generated between the output signals of the magnetoresistive elements adjacent to each other are provided between the output signals of both half bridge circuits. The rotation sensor according to any one of claims 1 to 13, wherein the rotation sensor is arranged so as to have a phase difference of 45 °.   A first full-bridge circuit in which a pair of the first half-bridge circuits are bridge-connected and a second full-bridge circuit in which a pair of the second half-bridge circuits are bridge-connected are each output of both full-bridge circuits. The rotation sensor according to claim 14, wherein the rotation sensor is arranged so that a phase difference of 45 degrees is generated between the signals.   The rotation sensor according to claim 14 or 15, wherein the magnetoresistive elements constituting the first and second half-bridge circuits are alternately arranged concentrically.   17. The phase difference of 45 degrees between the signal created by the signal creation unit and each output signal of each Hall element, respectively. 17. Rotation sensor.   A value obtained by dividing 0 to 360 ° of the relative rotation angle by a phase difference between output signals of the Hall elements is n, and n angle ranges are set by dividing a range of 0 to 360 ° by n. 18. The rotation sensor according to claim 12, wherein combinations of comparison results in the comparison unit and the output unit are different in each angle range. . The angle calculator is
An angle corresponding to the relative rotation angle by performing feedback control so that a deviation between the relative rotation angle and an angle calculated using a plurality of output signals having phase differences output from the magnetoresistive elements is reduced. The rotation sensor according to claim 1, wherein the rotation sensor is calculated.   Each of the Hall elements is a vertical Hall element, and is arranged so that a surface direction of a magnetic detection surface of each vertical Hall element intersects with the magnetoresistive element region. The rotation sensor according to claim 19.   The rotation sensor according to any one of claims 1 to 20, wherein each of the magnetoresistive elements and the Hall elements is formed in a semiconductor substrate.   The rotation sensor according to any one of claims 1 to 21, wherein each Hall element has a CMOS transistor structure.   The rotation sensor according to claim 22, wherein each of the Hall elements has a high breakdown voltage CMOS transistor structure. The Hall element region is
A first conductivity type semiconductor substrate;
A second conductivity type semiconductor region formed at a predetermined depth from a surface layer in the semiconductor substrate;
A first conductivity type semiconductor region formed so as to divide the second conductivity type semiconductor region within the second conductivity type semiconductor region and shallower than the second conductivity type semiconductor region;
A second conductivity type impurity diffusion region for contact forming a current supply pair, formed on the surface layer portion of the second conductivity type semiconductor region with the first conductivity type semiconductor region interposed therebetween;
A second conductivity type impurity diffusion region for contact, which is formed in a surface layer portion of the second conductivity type semiconductor region and constitutes a voltage output pair,
The magnetoresistive element region is
The rotation sensor according to claim 22 or 23, wherein at least a part of the rotation sensor is formed so as to overlap the hall element region with an insulating film interposed therebetween.   The rotation sensor according to any one of claims 1 to 24, wherein each of the magnetoresistive elements is formed of a NiFe thin film.   The rotation sensor according to any one of claims 1 to 24, wherein each of the magnetoresistive elements is made of a NiCo thin film.

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