JP6291380B2 - Non-contact rotation angle sensor - Google Patents

Description

  The present invention relates to a non-contact rotational angle sensor that detects rotational position information of a rotor.

  In motor control, rotation angle detection methods using a non-contact rotation angle sensor (rotary encoder) that detects rotor rotation position information are roughly classified into optical and magnetic methods. The magnetic non-contact rotation angle sensor has excellent durability against dirt as compared with the optical non-contact rotation angle sensor, and is often used mainly in the in-vehicle motor field. The rotor rotational position information detected by the non-contact rotational angle sensor is often used in vector control. For this reason, the non-contact rotation angle sensor is required to have high angle detection accuracy and high speed response.

  Patent Documents 1 and 2 disclose non-contact rotation angle sensors used for motor rotation control applications. Patent Document 1 discloses a non-contact rotation angle sensor that performs digital signal processing on the Hall electromotive force signal output from the Hall element and detects the rotational position information of the rotor. Further, Patent Document 2 includes a failure detection function for detecting a failure of the own machine in addition to a detection function for performing digital signal processing on the signal output from the resolver and detecting the rotational position information of the rotor. A non-contact rotation angle sensor is disclosed.

JP 2012-194193 A US Pat. No. 6,426,712

  In motor control applications, particularly in-vehicle motor control applications, when using a rotation angle sensor, the failure detection function of the own machine is an essential function. However, the non-contact rotation angle sensor disclosed in Patent Document 1 has a problem that it cannot detect a failure of the own device. Moreover, although the non-contact rotation angle sensor disclosed in Patent Document 2 can detect a failure of its own device, it requires a failure detection circuit, and thus has a problem that the circuit area increases.

  An object of the present invention is to provide a non-contact rotation angle sensor having a failure detection function in which an increase in circuit area is suppressed.

  To achieve the above object, a non-contact rotation angle sensor according to an aspect of the present invention includes an X-axis component detection unit that detects an X-axis component of a magnetic field based on a rotation angle of a rotor, and detects a Y-axis component of the magnetic field. A Y-axis component detection unit that outputs, a first ΔΣ modulation circuit that outputs a first ΔΣ modulation signal corresponding to the X-axis component, and a second that outputs a second ΔΣ modulation signal corresponding to the Y-axis component A ΔΣ modulation circuit, a cosine / sine data output unit that receives an angle signal and outputs cosine data and sine data corresponding to the angle signal, the first ΔΣ modulation signal, and the second ΔΣ modulation signal An outer product calculation circuit for calculating outer product data of the cosine data and the sine data, an angle signal output unit for integrating the outer product data and outputting the angle signal, the first ΔΣ modulation signal and the second ΔΣ modulation signal, the first data and the first data An inner product calculation circuit for calculating inner product data with the data, a digital filter for smoothing and outputting the inner product data, and selecting the cosine data and the sine data when in use mode, Third data and fourth data that are output as the second data and enable one of the first ΔΣ modulation signal and the second ΔΣ modulation signal and disable the other in the inspection mode, respectively. And a selection circuit that selects and outputs the data as the first data and the second data, respectively.

  In order to achieve the above object, a non-contact rotation angle sensor according to another aspect of the present invention includes an X-axis component detection unit that detects an X-axis component of a magnetic field based on a rotation angle of a rotor, and a Y-axis of the magnetic field. A Y-axis component detection unit for detecting a component; a first ΔΣ modulation circuit for outputting a first ΔΣ modulation signal corresponding to the X-axis component; and a second ΔΣ modulation signal corresponding to the Y-axis component A second ΔΣ modulation circuit, an outer product operation circuit for calculating outer product data of the first data, the second data, the third data, and the fourth data, and an integration for outputting an integration signal of the outer product data A signal output unit; a cosine / sine data output unit that receives an angle signal and outputs cosine data and sine data corresponding to the angle signal; and the first ΔΣ modulation signal and the first 2 ΔΣ modulation signal, the cosine data, and the sine And output as the first data, the second data, the third data, and the fourth data, respectively, and in the inspection mode, the first ΔΣ modulation signal or the And a selection circuit configured to select a second ΔΣ modulation signal and form a loop filter together with the outer product calculation circuit and the integration signal output unit to smooth the signal.

  The selection circuit selects and outputs the first ΔΣ modulation signal and the second ΔΣ modulation signal as the first data and the second data, respectively, in the use mode, and the inspection mode. At this time, one of the first ΔΣ modulation signal and the second ΔΣ modulation signal is selected and output as one of the first data and the second data, and data having a predetermined value is output. A first multiplexer that selects and outputs the first data and the second data as the other; and, in the use mode, selects the cosine data and the sine data to select the third data and Data that is output as the fourth data, and in the inspection mode, the integration signal is selected and output as one of the third data and the fourth data, and has a predetermined value. And a second multiplexer that outputs the other as the other of the third data and the fourth data.

  According to the present invention, an increase in circuit area can be suppressed.

It is a figure which shows typically the external appearance of the non-contact rotation angle sensor 1 by the 1st Embodiment of this invention. It is a figure which shows schematic structure of the rotation angle detection circuit 10 with which the non-contact rotation angle sensor 1 by the 1st Embodiment of this invention was equipped. It is a figure explaining the digital angle calculating circuit 12 with which the rotation angle detection circuit 10 of the non-contact rotation angle sensor 1 by the 1st Embodiment of this invention was equipped with the transfer function of a discrete time system. It is a figure which shows an example of the output signal selection table memorize | stored in the multiplexer circuit 23 with which the rotation angle detection circuit 10 of the non-contact rotation angle sensor 1 by the 1st Embodiment of this invention was equipped. It is a figure which shows the operation state of the multiplexer circuit 23 and the inner product calculating circuit 19 with which the rotation angle detection circuit 10 of the non-contact rotation angle sensor 1 by the 1st Embodiment of this invention was equipped. 1 is a block diagram showing a schematic circuit configuration of a rotation angle detection circuit 101 provided in a non-contact rotation angle sensor of a related technology of the non-contact rotation angle sensor 1 according to the first embodiment of the present invention. It is a block diagram which shows the schematic circuit structure of the rotation angle detection circuit 201 with which the non-contact rotation angle sensor of the other related art of the non-contact rotation angle sensor 1 by the 1st Embodiment of this invention was equipped. It is a block diagram which shows the schematic circuit structure of the rotation angle detection circuit 51 with which the non-contact rotation angle sensor by the 2nd Embodiment of this invention was equipped. It is a figure which shows an example of the output signal selection table memorize | stored in the multiplexer circuit 53 with which the rotation angle detection circuit 51 of the non-contact rotation angle sensor by the 2nd Embodiment of this invention was equipped. It is a figure which shows the operation state of the multiplexer circuit 53 with which the rotation angle detection circuit 51 of the non-contact rotation angle sensor by the 2nd Embodiment of this invention was equipped. It is a figure which shows the operation state of the multiplexer circuit 53 with which the rotation angle detection circuit 51 of the non-contact rotation angle sensor by the 2nd Embodiment of this invention was equipped. It is a figure which shows the operation state of the multiplexer circuit 53 with which the rotation angle detection circuit 51 of the non-contact rotation angle sensor by the 2nd Embodiment of this invention was equipped (the 3).

[First Embodiment]
A non-contact rotation angle sensor according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram schematically illustrating the appearance of a non-contact rotation angle sensor 1 according to the present embodiment. FIG. 1A schematically shows the upper surface of the non-contact rotation angle sensor 1, and FIG. 1B schematically shows a state in which the non-contact rotation angle sensor 1 is installed on the rotor that is the detection target of the rotation position information. It shows. FIG. 1B shows a state viewed from one side of the non-contact rotation angle sensor 1.

  As shown in FIG. 1A, the non-contact rotation angle sensor 1 includes an X Hall element (an example of an X axis component detection unit) 3 and a Y Hall element (Y axis component detection) in an IC (integrated circuit) package 29. Part) 5 and a rotation angle detection circuit 10 (not shown in FIG. 1) described later. The X Hall element 3 includes a first X Hall element 3 a and a second X Hall element 3 b that are arranged to face each other in a plane parallel to the upper surface of the IC package 29. The Y Hall element 5 includes a first Y Hall element 5 a and a second Y Hall element 5 b that are arranged to face each other in a plane parallel to the upper surface of the IC package 29. The first and second X Hall elements 3a and 3b and the first and second Y Hall elements 5a and 5b are arranged in the same plane. The direction in which the first and second X Hall elements 3a and 3b are arranged is substantially orthogonal to the direction in which the first and second Y Hall elements 5a and 5b are arranged. For convenience of explanation, as shown in FIG. 1, the arrangement direction of the first and second X Hall elements 3a, 3b is taken as the X axis, and the arrangement direction of the first and second Y Hall elements 5a, 5b is taken as the Y axis, The Z axis is taken in a direction perpendicular to both the Y axis and the Y axis. The positive direction of the X axis is a direction from the first X Hall element 3a toward the second X Hall element 3b. The positive direction of the Y axis is a direction from the first Y Hall element 5a toward the second Y Hall element 5b. The positive direction of the Z axis is a direction from the bottom surface of the IC package 29 toward the top surface.

  As shown in FIG. 1B, the rotor 31 is arranged on the upper surface of the IC package 29 with a certain interval. The rotor 31 has an output shaft 31a extending in a direction orthogonal to the upper surface of the IC package 29, and a permanent magnet 31b provided at the end of the output shaft 31a on the IC package 29 side. The output shaft 31a has, for example, a cylindrical shape. The permanent magnet 31b has a thin disk shape. The central axis of the output shaft 31a coincides with the central axis of the permanent magnet 31b. The direction parallel to the central axis of the output shaft 31 a and the permanent magnet 31 b coincides with the Z-axis direction, that is, the direction orthogonal to the upper surface of the IC package 29.

  The permanent magnet 31b and the upper surface of the IC package 29 are disposed in close proximity to each other. The permanent magnet 31b and the X Hall element 3 and the Y Hall element 5 are arranged close to each other and opposed to each other. The X Hall element 3 and the Y Hall element 5 are fixedly disposed in the IC package 29. On the other hand, the rotor 31 rotates about the central axis of the output shaft 31a as a rotation axis, as indicated by a broken line arrow in FIG. As the rotor 31 rotates, the permanent magnet 31b also rotates. For this reason, the strength and direction of the magnetic field formed by the permanent magnet 31 b change relative to the X Hall element 3 and the Y Hall element 5. The X Hall element 3 and the Y Hall element 5 detect a relative change in the magnetic field formed by the permanent magnet 31b as a Hall electromotive force signal. The non-contact rotation angle sensor 1 detects the rotation angle of the rotor 31 based on the Hall electromotive force signals output from the X Hall element 3 and the Y Hall element 5.

  Next, a rotation angle detection circuit provided in the non-contact rotation angle sensor will be described with reference to FIGS. 2 to 5 with reference to FIG. FIG. 2 is a diagram showing a schematic configuration of the rotation angle detection circuit 10 provided in the non-contact rotation angle sensor 1 according to the present embodiment. The rotation angle detection circuit 10 has a rotation angle detection function for detecting the rotation angle of the rotor 31 and a failure detection function for detecting a failure of the own machine. FIG. 2A is a block diagram illustrating an example of a circuit configuration of the rotation angle detection circuit 10. FIG. 2B shows a signal waveform of the rotation angle detection circuit 10, and the upper part in FIG. 2B shows an example of the signal waveform of the output signal SHoy output from the Y Hall element 5, and FIG. The lower part in () shows an example of the signal waveform of the YΔΣ modulation signal Smdy output from the YΔΣ AD (analog-digital) conversion circuit 9.

  As shown in FIG. 2A, the rotation angle detection circuit 10 is based on the X Hall element 3 that detects the X axis component of the magnetic field based on the rotation angle of the rotor 31 (see FIG. 1) and the rotation angle of the rotor 31. And a Y Hall element 5 for detecting the Y axis component of the magnetic field. The X-axis component of the magnetic field detected by the X Hall element 3 is a component in the X-axis direction shown in FIGS. 1 (a) and 1 (b). The Y-axis component of the magnetic field detected by the Y Hall element 5 is a component in the Y-axis direction shown in FIGS. 1 (a) and 1 (b). The rotation angle detection circuit 10 also outputs an XΔΣ AD conversion circuit (first ΔΣ modulation) that outputs an XΔΣ modulation signal (an example of a first ΔΣ modulation signal) Smdx corresponding to the X-axis component of the magnetic field detected by the X Hall element 3. An example of a circuit) 7 and a YΔΣ AD conversion circuit (second ΔΣ modulation circuit) that outputs Smdy according to a YΔΣ modulation signal (an example of a second ΔΣ modulation signal) corresponding to the Y-axis component of the magnetic field detected by the Y Hall element 5 9.

  The Y Hall element 5 outputs a voltage corresponding to the strength of the magnetic field formed by the permanent magnet 31 b provided on the rotor 31 and the rotation angle θ of the magnet. As shown in the lower part of FIG. 2B, the signal waveform of the output signal SHoy based on the voltage output from the Y Hall element 5 is, for example, a sine wave. When the maximum value of the output signal SHoy is “A”, the signal waveform of the output signal SHoy can be represented by “A · sin θ”. “·” Between the maximum values “A” and “sin” or “cos” of the output signals output from the X Hall element 3 and the Y Hall element 5 represents the integration of A and the sine or cosine. The YΔΣ AD conversion circuit 9 converts the analog output signal SHoy input from the Y Hall element 5 into a digital signal, and outputs a YΔΣ modulation signal Smdy obtained by AD conversion. As shown in the lower part of FIG. 2B, the YΔΣ modulation signal Smdy is a 1-bit pulse signal. The YΔΣ modulation signal Smdy represents the data size by the density of the pulse signal. As the amplitude of the output signal SHoy output from the Y Hall element 5 increases, the number of pulses in the high level section of the YΔΣ modulation signal Smdy output from the YΔΣ AD conversion circuit 9 increases. This increases the density of the YΔΣ modulation signal Smdy. On the other hand, the smaller the amplitude of the output signal SHoy output from the Y Hall element 5, the smaller the number of pulses in the high level section of the YΔΣ modulation signal Smdy output from the YΔΣ AD conversion circuit 9. Thereby, the density of the YΔΣ modulation signal Smdy is lowered.

  Although not shown, the signal waveform of the output signal SHox output from the X Hall element 3 is, for example, a cosine wave and can be expressed as “A · cos θ”. The XΔΣ AD conversion circuit 7 converts the analog output signal SHox input from the X Hall element 3 into a digital signal, and outputs an XΔΣ modulation signal Smdx obtained by AD conversion. The XΔΣ modulation signal Smdx is a 1-bit pulse signal. In the XΔΣ modulation signal Smdx, the data size is represented by the density of the pulse signal in the same manner as the YΔΣ modulation signal Smdy. The relationship between the amplitude of the output signal SHox output from the X Hall element 3 and the number of pulses and the pulse density of the XΔΣ modulation signal Smdx output from the XΔΣ AD conversion circuit 7 is the same as that of the YΔΣ modulation signal Smdy.

  The rotation angle detection circuit 10 receives an angle detection signal (an example of an angle signal), and outputs a cosine data ROM (read-only storage device) 11 that outputs cosine data and sine data according to the input angle detection signal. An angle error signal (an example of outer product data) Sae is obtained by calculating the cross product of the output signal SHox output from the X Hall element 3 and the output signal SHoy output from the Y Hall element 5 and the cosine data and sine data output from the sine wave data ROM 11. And an outer product calculation circuit 13 for outputting.

  The sine wave data ROM 11 is an example of a cosine / sine data output unit. The sine wave data ROM 11 outputs 12-bit cosine data and sine data according to the input angle signal. The angle signal input to the sine wave data ROM 11 is an angle detection signal Sφ (n) output from an integration circuit 17 described later. The sine wave data ROM 11 outputs cosine data Dcos and sine data Dsin corresponding to the angle φ (n) represented by the input angle detection signal Sφ (n) to the outer product calculation circuit 13.

The outer product calculation circuit 13 includes a first input terminal Icp1 to which the XΔΣ modulation signal Smdx output from the XΔΣAD conversion circuit 7 is input, a second input terminal Icp2 to which the YΔΣ modulation signal Smdy output from the YΔΣ AD conversion circuit 9 is input, and a sine wave It has a third input terminal Icp3 to which the cosine data Dcos output from the data ROM 11 is input, and a fourth input terminal Icp4 to which the sine data Dsin output from the sine wave data ROM 11 is input. In FIG. 2A, for the first to fourth input terminals Icp1, Icp2, Icp3, and Icp4, the letters “Icp” are omitted and only the numerical values of the input terminals are shown. The outer product calculation circuit 13 calculates the angular error signal Sae by calculating the outer product of the signal input to the first input terminal Icp1 and the second input terminal Icp2 and the signal input to the third input terminal Icp3 and the fourth input terminal Icp4, respectively. Is output. The angle error signal Sae is output from an output terminal Ocp provided in the outer product calculation circuit 13. When the outer product calculation executed by the outer product calculation circuit 13 is expressed using the sign of each terminal, the following equation (1) is obtained.
Ocp = Icp1 × Icp4-Icp2 × Icp3 (1)

A signal input to the first input terminal Icp1 of the outer product calculation circuit 13 is an XΔΣ modulation signal Smdx output from the XΔΣ AD conversion circuit 7. The signal input to the second input terminal Icp2 of the outer product calculation circuit 13 is the YΔΣ modulation signal Smdy output from the YΔΣ AD conversion circuit 9. A signal input to the third input terminal Icp3 of the outer product calculation circuit 13 is cosine data Dcos output from the sine wave data ROM 11. The signal input to the fourth input terminal Icp4 of the outer product calculation circuit 13 is sine data Dsin output from the sine wave data ROM 11. For example, the XΔΣ modulation signal Smdx is “A · cos θ”, the YΔΣ modulation signal Smdy is “A · sin θ”, the cosine data Dcos is “cos (φ (n))”, and the sine data Dsin is “sin (φ ( n)) ”, the angular error signal Sae output from the output terminal Ocp by the outer product arithmetic circuit 13 from the equation (1) and the addition theorem is as follows.
Angle error signal Sae = A · cos θ × sin (φ (n))
−A · sin θ × cos (φ (n)
= A · sin (φ (n) -θ)

Since the angle error signal Sae converges to 0 and becomes a sufficiently small value due to the closed loop characteristic, “sin (φ (n) −θ)” can be approximated as “φ (n) −θ”. Therefore, the angle error signal Sae is “A × (φ (n) −θ)”.
The rotation angle detection circuit 10 integrates the phase compensation circuit 15 to which the angle error signal Sae output from the outer product calculation circuit 13 is input and the angle error signal Sae output from the phase compensation circuit 15 to obtain the angle detection signal Sφ (n). And an integrating circuit (an example of an angle signal output unit) 17 for outputting.

  The phase compensation circuit 15 has an all-pass filter characteristic. For this reason, the angle error signal Sae output from the phase compensation circuit 15 has the same amplitude characteristics as the angle error signal Sae output from the outer product calculation circuit 13 except for the phase. The phase compensation circuit 15 is arranged to prevent oscillation of the closed loop L1 configured by the outer product calculation circuit 13, the phase compensation circuit 15, the integration circuit 17, and the sine wave data ROM 11. In the present embodiment, the phase compensation circuit 15 is disposed at the subsequent stage of the outer product calculation circuit 13, but may be disposed at the subsequent stage of the integration circuit 17 or the preceding stage of the sine wave data ROM 11. Also in this case, the phase compensation circuit 15 can prevent oscillation of the closed loop L1.

The integration circuit 17 is a circuit that integrates the angle error signal Sae, and functions as a loop filter for reducing a noise signal superimposed on the angle error signal Sae by forming a closed loop L1. The angle detection signal Sφ (n) output from the integration circuit 17 is fed back to the input of the integration circuit 17 via the sine wave data ROM 11 by the closed loop L1. Thus, the angle error signal “A × (φ (n) −θ)” is converged to zero. The angle error signal “A × (φ (n) −θ)” output from the outer product calculation circuit 13 is based on the 1-bit XΔΣ modulation signals Smdx and Smdy output from the XΔΣ AD conversion circuit 7 and the YΣ AD conversion circuit 9, respectively. . Therefore, the angle error signal “A × (φ (n) −θ)” contains a lot of noise signals, and is smoothed and bit-extended through the phase compensation circuit 15 and the integration circuit 17. Thereby, the angle detection signal Sφ (n) finally output from the integration circuit 17 is output as angle data having a resolution of 12 bits (0 to 4095 LSB). When the resolution of φ (n) is 0 to 4095 LSB, the relationship between the angle detection signal Sφ (n) and the actual rotation angle θ of the rotor 31 can be expressed as follows.
θ = φ (n) × 360 ° / 4096

  The rotation angle detection circuit 10 includes a multiplexer circuit (an example of a selection circuit) 23 that outputs first data D1 and second data D2, an XΔΣ modulation signal Smdx and a YΔΣ modulation signal Smdy, and first data D1 and first data D1. And a digital filter circuit 21 that smoothes the inner product data Dsp output from the inner product operation circuit 19 and outputs an amplitude signal Sap. Further, the rotation angle detection circuit 10 includes an activation / invalidation data generation circuit 27 that generates validation data (an example of third data) Dmdv and invalidation data (an example of fourth data) Dmdi, and a multiplexer circuit And a control signal generation circuit 25 for generating a control signal Sc to be output to 23.

  The multiplexer circuit 23 receives cosine data Dcos and sine data Dsin output from the sine wave data ROM 11, and validation data Dmdv and invalidation data Dmdi output from the validation / invalidation data generation circuit 27. The multiplexer circuit 23 selects cosine data Dcos and sine data Dsin output from the sine wave data ROM 11 when the non-contact rotation angle sensor 1 is in the use mode. The multiplexer circuit 23 outputs the selected cosine data Dcos and sine data Dsin to the inner product calculation circuit 19 as first data D1 and second data D2, respectively. The multiplexer circuit 23 selects the first data D1 by selecting the validation data Dmdv and the invalidation data Dmdi output from the validation / invalidation data generation circuit 27 when the non-contact rotation angle sensor 1 is in the inspection mode. And the second data D2 are output to the inner product calculation circuit 19, respectively. The multiplexer circuit 23 has a first output terminal Omp1 and a second output terminal Omp2 that output the first or second data D1, D2. The multiplexer circuit 23 determines which of the first and second data D1, D2 is output from the first and second output terminals Mot1, Mot2 according to the value of the control signal Sc input from the control signal generation circuit 25. It is supposed to be.

  The control signal Sc output from the control signal generation circuit 25 has information indicating whether the non-contact rotation angle sensor 1 is currently in the use mode or the inspection mode. For example, it is determined that the non-contact rotation angle sensor 1 is in the use mode when the value of the control signal Sc is “0”, and the non-contact rotation angle sensor when the value of the control signal Sc is “1” or “2”. It is determined that 1 is the inspection mode.

The validation data Dmdv and invalidation data Dmdi generated by the validation / invalidation data generation circuit 27 are each 12-bit data. The validation data Dmdv is, for example, 2 ¹² LSB, and the invalidation data Dmdi is, for example, 0 LSB.

  The validation data Dmdv output from the multiplexer circuit 23 is data that is output to the inner product calculation circuit 19 and enables one of the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy input to the inner product calculation circuit 19. The invalidation data Dmdi output from the multiplexer circuit 23 is data that is output to the inner product calculation circuit 19 and invalidates the other of the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy input to the inner product calculation circuit 19.

The inner product calculation circuit 19 receives a first input terminal Isp1 to which a data signal output from the first output terminal Omp1 of the multiplexer circuit 23 is input and a data signal output from the second output terminal Omp2 of the multiplexer circuit 23. A second input terminal Isp2, a third input terminal Isp3 to which the XΔΣ modulation signal Smdx output from the XΔΣ AD conversion circuit 7 is input, and a fourth input terminal Isp4 to which the YΔΣ modulation signal Smdy output from the YΔΣ AD conversion circuit 9 is input. ing. In FIG. 2A, for the first to fourth input terminals Isp1, Isp2, Isp3, and Isp4, the letters “Isp” are omitted and only the numerical values of the respective input terminals are shown. The inner product operation circuit 19 performs an inner product operation on the data signals input to the first input terminal Isp1 and the second input terminal Isp2 and the signals input to the third input terminal Isp3 and the fourth input terminal Isp4, respectively, thereby calculating the inner product data Dsp. Is output. The inner product data Dsp is output from an output terminal Osp provided in the inner product operation circuit 19. When the outer product calculation executed by the inner product calculation circuit 19 is expressed using the sign of each terminal, the following equation (2) is obtained.
Osp = Isp1 × Isp3 + Isp2 × Isp4 (2)

  Although details will be described later, the signals input to the third and fourth input terminals Isp3 and Isp4 are the XΔΣ modulation signal Smdx and the YΔΣ modulation signal regardless of whether the non-contact rotation angle sensor 1 is in the use mode or the inspection mode. While not changed by Smdy, the signals input to the first and second input terminals Isp2 and Isp2 are different depending on the operating state of the non-contact rotation angle sensor 1.

  The digital filter circuit 21 averages the inner product data Dsp output from the inner product calculation circuit 19 and outputs a 12-bit amplitude signal Sap. The digital filter circuit 21 exhibits a low-pass filter function for smoothing the inner product data Dsp.

  As described above, the rotation angle detection circuit 10 includes the X Hall element 3 and the Y Hall element 5 that output the output signals SHox and SHoy corresponding to the magnetic field strength and the rotation angle θ of the permanent magnet 31b, and the analog output signals SHox and SHoy. XΔΣ AD conversion circuit 7 and YΔΣ AD conversion circuit 9 for modulating the signal into a 1-bit signal, a closed-loop digital angle calculation circuit 12, an inner product calculation circuit 19, and a multiplexer circuit for selecting and switching a data signal input to the inner product calculation circuit 19 23 and a digital filter circuit 21 that averages the data signal output from the inner product calculation circuit 19 are provided as main components. The closed-loop digital angle calculation circuit 12 includes an outer product calculation circuit 13, a phase compensation circuit 15, an integration circuit 17, and a sine wave data ROM 11.

  Magnetic rotation angle sensors such as Hall elements, MR (Magneto-Resistance) elements, and resolvers all output analog voltages synchronized with the rotation of the rotating body as signals. In a magnetic rotation angle sensor, an analog signal output from a sensor such as a Hall element is converted into a digital signal by an AD conversion circuit, and then angular position information is calculated by a digital circuit unit. A closed loop (servo) circuit is used as a signal processing circuit for detecting angular position information in the digital circuit section. A rotation angle detection circuit using a closed loop signal processing circuit can minimize the delay time due to signal processing necessary for angle detection. For this reason, the angle detection circuit using the closed loop signal processing circuit is a very suitable signal processing circuit in the non-contact rotation angle sensor in the motor control.

  Also in this embodiment, the digital angle calculation circuit 12 using a closed loop signal processing circuit is used. The digital angle calculation circuit 12 includes an XΔΣ modulation signal Smdx and a YΔΣ modulation signal Smdy obtained by modulating the output signals SHox, SHoy (for example, A · cos θ, A · sin θ) to 1 bit, and cosine data Dcos ( For example, a cross product operation is performed between cos φ (n)) and sine data D sin (for example, sin (φ (n))). The digital angle calculation circuit 12 is fed back so that the calculated angle error signal “φ (n) −θ” converges to zero. The digital angle calculation circuit 12 can be equivalently expressed by a transfer function of a discrete time system.

  FIG. 3 is a diagram illustrating the digital angle calculation circuit 12 using a transfer function of a discrete time system. FIG. 3A is a block diagram equivalently representing the digital angle calculation circuit 12 with a transfer function of a discrete time system. FIG. 3B is a graph showing an example of loop filter characteristics when the operating frequency of the digital angle calculation circuit 12 is 2 MHz. The horizontal axis indicates the frequency f (Hz), and the vertical axis indicates the amplification factor (dB).

As shown in FIG. 3A, the digital angle calculation circuit 12 equivalently represented by a transfer function of a discrete time system includes an adder / subtractor 35 and a transfer function “(1-bZ ⁻¹ ) / (1-aZ”. ⁻¹ ) ”and a phase compensation circuit 37 represented by two transfer functions“ c / (1-Z ⁻¹ ) ”. “A” in the transfer function is “2047/2048”, “b” is “2040/2048”, and c is “2/2048”. The output signal output from the integration circuit 39 is input to the adder / subtractor 35. Thus, a closed loop is formed by the adder / subtractor 35, the phase compensation circuit 37, and the integration circuit 39. In addition to the output signal of the integration circuit 39, the adder / subtractor 35 receives a 1-bit output signal output from the amplifier circuit 33. The amplifier circuit 33 corresponds to the XΔΣ AD converter circuit 7 and the YΔΣ AD converter circuit 9 shown in FIG. 2A and outputs a 1-bit signal. The adder / subtractor 35 outputs a difference signal SO obtained by subtracting the output signal of the integration circuit 39 from the output signal of the amplifier circuit 33 to the phase compensation circuit 37.

  As shown in FIG. 3 (b), the closed loop filter characteristic formed by the digital angle calculation circuit 12 in the configuration of the transfer function shown in FIG. 3 (a) is a low-pass in a band of about 1 kHz when the operating frequency is 2 MHz. Filter characteristics. For this reason, the digital angle calculation circuit 12 has sufficient filter characteristics to suppress noise (for example, quantization noise of several hundred kHz to several MHz) included in the 1-bit signal. If the XΔΣ AD conversion circuit 7 and the YΔΣ AD conversion circuit 9 have a 12-bit resolution, the output signal output from the amplifier circuit 33 is effectively a 1-bit (0 or 4095 LSB binary) signal. It becomes. When the 1-bit output signal input to the adder / subtractor 35 is input to the closed loop formed by the digital angle calculation circuit 12, that is, when output from the adder / subtractor 35, the sine wave data ROM 11 (see FIG. 2A). Bit expansion is performed to 12 bits corresponding to the number of bits of the output cosine data Dcos and sine data Dsin. The digital angle calculation circuit 12 reduces the noise superimposed on the signal by passing the signal extended to 12 bits (actually, a binary signal of 0 or 4095 LSB) via the phase compensation circuit 37 and the integration circuit 39. , And feedback to the adder / subtractor 35. As a result, the digital angle calculation circuit 12 converges the difference signal SO output from the adder / subtractor 35 to zero. The value of the 12-bit output signal output from the integration circuit 39 is equal to the value of the signal input to the adder / subtractor 35. The signal input to the adder / subtractor 35 is smoothed by the closed-loop low-pass filter characteristic formed by the digital angle calculation circuit 12. Therefore, the binary digital signal input to the digital angle calculation circuit 12 is converted as a digital data signal having an accurate 12-bit resolution.

  Returning to FIG. 2, X and YΔΣ AD conversion circuits 7 and 9 that perform 1-bit modulation are used as AD conversion circuits that convert analog output signals SHox and SHoy output from the X Hall element 3 and the Y Hall element 5 into digital signals. The advantage of using is that the outer product calculation circuit 13 which is a calculation part of the angle error signal Sae can be made a simple configuration using an adder / subtracter. Although the 12-bit cosine and sine data Dcos and Dsin are input from the sine wave data ROM 11 to the outer product calculation circuit 13, 1-bit X and Y modulation signals Smdx and Smdy are input from the X and YΔΣ AD conversion circuits 7 and 9. To do. For this reason, the outer product operation of the cosine and sine data Dcos and Dsin and the X and Y modulation signals Smdx and Smdy can be performed only by addition and subtraction without multiplication. Therefore, the outer product calculation circuit 13 does not require a multiplier that is a large-scale circuit, can be realized with a simple configuration using an adder / subtracter, and can reduce the circuit scale.

  Next, focusing on the operation of the multiplexer circuit 23, the operation of the non-contact rotation angle sensor 1 according to the present embodiment will be described with reference to FIG. FIG. 4 is an example of an output signal selection table showing the relationship between the value of the control signal Sc input to the multiplexer circuit 23 and the output signals output from the first and second output terminals Omp1, Omp2. The output signal selection table is stored in a predetermined storage unit (not shown) provided in the multiplexer circuit 23. The output signal selection table is divided into two fields, a “control signal” column and an “output signal” column. “Control signal” indicates the control signal Sc generated by the control signal generation circuit 25 and input to the multiplexer circuit 23. “Output signal” indicates an output signal output from the multiplexer circuit 23. The “output signal” field is divided into two fields, a “D1” field and a “D2” field. “D1” indicates the first data D1 output from the first output terminal Omp1 of the multiplexer circuit 23, and “D2” indicates the second data D2 output from the second output terminal Omp2 of the multiplexer circuit 23. ing. In the “control signal” column, possible values “0”, “1”, and “2” of the control signal Sc are stored. In the “D1” column and the “D2” column, the types of output signals output from the first and second output terminals Omp1 and Omp2 as the first and second data D1 and D2 according to the value of the control signal Sc, respectively. Is stored.

  FIG. 5 is a diagram illustrating the operation states of the multiplexer circuit 23 and the inner product operation circuit 19. FIG. 5A shows the operating state of the multiplexer circuit 23 and the inner product operation circuit 19 when the value of the control signal Sc is “0”, and FIG. 5B shows the value of the control signal Sc being “1”. FIG. 5C shows the operation state of the multiplexer circuit 23 and the inner product operation circuit 19 when the value of the control signal Sc is “2”. .

  As described above, the rotation angle detection circuit 10 detects the change in the magnetic field accompanying the rotation of the rotor 3 with the X Hall element 3 and the Y Hall element 5. Next, the rotation angle detection circuit 10 converts the analog output signals SHox and SHoy output from the X and Y Hall elements 3 and 5 into X and Y modulation signals which are 1-bit digital signals by the X and YΔΣ AD conversion circuits 7 and 9. The data is converted into Smdx and Smdy and output to the outer product calculation circuit 13. The rotation angle detection circuit 10 includes an angle detection signal Sφ (equal to the X and Y modulation signals Smdx, Smdy by a digital angle calculation circuit 12 constituted by an outer product calculation circuit 13, a phase compensation circuit 15, an integration circuit 17 and a sine wave data ROM 11. n) is output. At this time, the digital angle calculation circuit 12 feeds back the angle detection signal Sφ (n) in the closed loop L1 formed by the outer product calculation circuit 13, the phase compensation circuit 15, the integration circuit 17 and the sine wave data ROM 11, and the outer product calculation circuit 13 The angle error signal Sae output by is converged to “0”. The rotation angle detection circuit 10 operates as described above regardless of whether the operation state of the non-contact rotation angle sensor 1 is the use mode or the inspection mode.

  As shown in FIG. 4, in the output signal selection table, “Dcos” is stored in the “D1” column and “Dsin” is stored in the “D2” column corresponding to “0” in the “control signal” column. Has been. For this reason, as shown in FIG. 5A, when the operation state of the non-contact rotation angle sensor 1 is the use mode and the value of the control signal Sc is “0”, the multiplexer circuit 23 reads from the sine wave data ROM 11. Input cosine data Dcos and sine data Dsin are selected. The multiplexer circuit 23 outputs the cosine data Dcos as the first data D1 from the first output terminal Omp1, and outputs the sine data Dsin as the second data D2 from the second output terminal Opm2.

The inner product calculation circuit 19 calculates the inner product of the signals input to the first and second input terminals Isp1 and Isp2 and the input signals input to the third and fourth input terminals Isp3 and Isp4 based on the above equation (2). The calculated inner product data Dsp is calculated. The cosine data Dcos input to the first input terminal Isp1 is “cos (φ (n))”, the sine data Dsin input to the second input terminal Isp2 is “sin (φ (n))”, and the third input terminal The XΔΣ modulation signal Smdx input to Isp3 is “A · cos θ (1 bit)”, and the YΔΣ modulation signal Smdy input to the fourth input terminal Isp4 is “A · sin θ (1 bit)”. In this case, from the expression (2), the inner product data Dsp is “A · cos θ (1 bit) × cos (φ (n)) + A · sin θ (1 bit) × sin (φ (n))”. The value “φ (n)” of the angle detection signal Sφ (n) is “θ”. For this reason, the inner product data Dsp becomes “A” represented by a digital signal from the Pythagorean theorem (sin ² θ + cos ² θ = 1) after suppressing noise due to 1-bit modulation by the subsequent digital filter circuit 21. .

  As shown in FIG. 2A, the digital filter circuit 21 arranged at the subsequent stage of the inner product operation circuit 19 smooths the digital signal output from the inner product operation circuit 19 and has a value “A” that ensures 12-bit resolution. An amplitude signal Sap is output. At this time, the amplitude signal Sap becomes a value proportional to the magnetic field strength in the XY plane applied to the X and Y Hall elements 3 and 5.

  As shown in FIG. 4, in the output signal selection table, “Dmdv” is stored in the “D1” column and “Dmdi” is stored in the “D2” column corresponding to “1” in the “control signal” column. Has been. Therefore, as shown in FIG. 5B, when the operation state of the non-contact rotation angle sensor 1 is the inspection mode and the value of the control signal Sc is “1”, the multiplexer circuit 23 enables / disables The validation data Dmdv and invalidation data Dmdi input from the data generation circuit 27 are selected. Then, the multiplexer circuit 23 outputs the validation data Dmdv as the first data D1 from the first output terminal Omp1, and outputs the invalidation data Dmdi as the second data D2 from the second output terminal Opm2.

The validation data Dmdv input to the first input terminal Isp1 is “2 ¹² LSB”, the invalidation data Dmdi input to the second input terminal Isp2 is “0LSB”, and the XΔΣ modulation signal Smdx input to the third input terminal Isp3 Is “A · cos θ (1 bit)”, and the YΔΣ modulation signal Smdy input to the fourth input terminal Isp4 is “A · sin θ (1 bit)”. In this case, from the expression (2), the inner product data Dsp is “A · cos θ (1 bit) × 2 ¹² LSB + A · sin θ (1 bit) × 0 LSB”. Therefore, the inner product data Dsp is “A · cos θ (1 bit) × 2 ¹² LSB”.

The XΔΣ modulation signal Smdx is a binary signal of 0 or 1 in which A · cos θ is 1 bit. Therefore, the inner product data Dsp output from the inner product calculation circuit 19 is a binary signal of 0 LSB or 2 ¹² LSB. The digital filter circuit 21 arranged at the subsequent stage of the inner product operation circuit 19 smoothes the 0LSB and 2 ¹² LSB output from the inner product operation circuit 19, ensures 12-bit resolution, and an amplitude signal of a 12-bit value “A · cos θ”. Output Sap. At this time, the amplitude signal Sap becomes a value proportional to the X-axis component of the magnetic field strength in the XY plane applied to the X and Y Hall elements 3 and 5.

  As shown in FIG. 4, in the output signal selection table, “Dmdi” is stored in the “D1” column and “Dmdv” is stored in the “D2” column corresponding to “2” in the “control signal” column. Has been. Therefore, as shown in FIG. 5C, when the operation state of the non-contact rotation angle sensor 1 is the inspection mode and the value of the control signal Sc is “2”, the multiplexer circuit 23 is enabled / disabled. The validation data Dmdv and invalidation data Dmdi input from the data generation circuit 27 are selected. Then, the multiplexer circuit 23 outputs the invalidation data Dmdi as the first data D1 from the first output terminal Omp1, and outputs the validation data Dmdv as the second data D2 from the second output terminal Opm2.

The invalidation data Dmdi inputted to the first input terminal Isp1 is set to “0LSB”, the validation data Dmdv inputted to the second input terminal Isp2 is set to “2 ¹² LSB”, and the XΔΣ modulation signal Smdx inputted to the third input terminal Isp3. Is “A · cos θ”, and the YΔΣ modulation signal Smdy input to the fourth input terminal Isp4 is “A · sin θ”. From the expression (2), the inner product data Dsp is “A · sin θ (1 bit) × 2 ¹² LSB” (= A · cos θ × 0 LSB + A · sin θ × 2 ¹² LSB).

The YΔΣ modulation signal Smdy is a binary signal of 0 or 1 in which A · sin θ is 1 bit. Therefore, the inner product data Dsp output from the inner product calculation circuit 19 is a binary signal of 0 LSB or 2 ¹² LSB. The digital filter circuit 21 arranged at the subsequent stage of the inner product operation circuit 19 smoothes the 0LSB and 2 ¹² LSB output from the inner product operation circuit 19, ensures 12-bit resolution, and an amplitude signal of the 12-bit value “A · sin θ”. Output Sap. At this time, the amplitude signal Sap is a value proportional to the Y-axis component of the magnetic field strength in the XY plane applied to the X and Y Hall elements 3 and 5.

  In this embodiment, all the digital filter circuits used for converting “A”, “A · cos θ”, and “A · sin θ” into 12-bit values are the same circuit (ie, the digital filter circuit 21). . For this reason, the non-contact rotation angle sensor 1 according to the present embodiment does not require a plurality of digital filter circuits having a relatively large circuit area, and only adds the multiplexer circuit 23 having a simple configuration, so that “A”, “A · It is possible to output three signals of “cos θ” and “A · sin θ”. As will be described later, each of the signals “A · cos θ” and “A · sin θ” is used to detect or correct an angle error included in the angle detection signal due to a failure detection of the digital angle calculation circuit or a secular change. This is a useful signal.

  Next, the effects of the non-contact rotation angle sensor 1 will be described with reference to FIGS. 2 and 5 while comparing the non-contact rotation angle sensor 1 according to the present embodiment with related technologies related to the non-contact rotation angle sensor 1. This will be described with reference to FIGS.

  FIG. 6 is a block diagram showing a schematic configuration of a rotation angle detection circuit 101 provided in a non-contact rotation angle sensor as the first related technique disclosed in Patent Document 1 and Patent Document 2. The rotation angle detection circuit 101 has a failure detection function. As illustrated in FIG. 6, the rotation angle detection circuit 101 includes a closed-loop digital angle calculation circuit 102. The digital angle calculation circuit 102 includes an outer product calculation circuit 113, a phase compensation circuit 115, an integration circuit 117, and a sine wave data ROM 111. The outer product calculation circuit 113 calculates the outer product of the input XΔΣ modulation signal Smdx and YΔΣ modulation signal Smdy and the cosine data Dcos and sine data Dsin output from the sine wave data ROM 111, and outputs the angle error signal Sae to the phase compensation circuit 115. To do. The rotation angle detection circuit 101 includes an X Hall element 103 and a Y Hall element 105 that exhibit the same functions as the X Hall element 3 and the Y Hall element 5, and an XΔΣ AD conversion that exhibits the same functions as the XΔΣ AD conversion circuit 7 and the YΔΣ AD conversion circuit 9. A circuit 107 and a YΔΣ AD conversion circuit 109. X and YΔΣ AD conversion circuits 107 and 109 output X and YΔΣ modulation signals Smdx and Smdy, respectively, input to the outer product calculation circuit 113.

  The X and YΔΣ modulation signals Smdx and Smdy output from the X and YΔΣ AD conversion circuits 107 and 109 are sine waves when they are input to the closed loop formed by the digital angle calculation circuit 102, that is, when they are output from the outer product calculation circuit 113. Bit expansion is performed to 12 bits corresponding to the number of bits of cosine data Dcos and sine data Dsin output from the data ROM 111. The digital angle calculation circuit 102 passes a signal extended to 12 bits (actually a binary digital signal having a minimum value and a maximum value) via the phase compensation circuit 115 and the integration circuit 117, and noise superimposed on this signal. And fed back to the outer product calculation circuit 113. As a result, the digital angle calculation circuit 102 converges the angle error signal Sae output from the outer product calculation circuit 113 to zero.

  The rotation angle detection circuit 101 calculates the inner product of the XΔΣ modulation signal Smdx and YΔΣ modulation signal Smdy input from the XΔΣ AD conversion circuit 107 and the YΔΣ AD conversion circuit 109 and the cosine data Dcos and sine data Dsin input from the sine wave data ROM 111. An inner product arithmetic circuit 119, a digital filter circuit 121 to which the inner product data Dsp output from the inner product arithmetic circuit 119 is input, and a threshold determination circuit 123 to which the amplitude signal Sap output from the digital filter circuit 121 is input. The digital filter circuit 121 smoothes the inner product data Dsp of the digital signal output from the inner product operation circuit 119, and outputs an amplitude signal Sap having a value with a predetermined bit (for example, 12 bits) resolution.

  The rotation angle detection circuit 101 according to the first related technique includes an inner product calculation circuit 119 in addition to the outer product calculation circuit 113 that calculates an angle error signal, and thus the amplitude signal Sap is obtained based on the angle detection signal Sφ (n). It can be detected. Further, the rotation angle detection circuit 101 includes the threshold determination circuit 123, so that an error is determined when the signals from the X and Y Hall elements 103 and 105 are too large or too small, and error signals Ser1 and Ser2 are output. It is possible to do. For example, the threshold determination circuit 123 receives an upper threshold signal Sup and a lower threshold signal Slo.

The cosine data Dcos input to the first input terminal Isp1 of the inner product arithmetic circuit 119 is “cos (φ (n))”, and the sine data Dsin input to the second input terminal Isp2 is “sin (φ (n))”. The XΔΣ modulation signal Smdx input to the third input terminal Isp3 is “A · cos θ”, and the YΔΣ modulation signal Smdy input to the fourth input terminal Isp4 is “A · sin θ”. In FIG. 6, for the first to fourth input terminals Isp1, Isp2, Isp3, and Isp4 of the inner product calculation circuit 119, the characters “Isp” are omitted and only the numerical values of the input terminals are shown. From the equation (2), the inner product data Dsp is “A · cos θ (1 bit) × cos (φ (n)) + A · sin θ (1 bit) × sin (φ (n))”. The value “φ (n)” of the angle detection signal Sφ (n) is “θ”. Therefore, the inner product data Dsp is “A” represented by a digital signal by the Pythagorean theorem (sin ² θ + cos ² θ = 1).

  Since the inner product data Dsp output from the inner product operation circuit 119 is calculated based on a 1-bit signal, it contains a lot of noise accompanying 1-bit quantization. Therefore, the rotation angle detection circuit 101 can provide the digital filter circuit 121 having a low-pass filter characteristic after the inner product calculation circuit 119 to smooth the inner product data Dsp and calculate the amplitude signal Sap with necessary accuracy and resolution. ing. The threshold determination circuit 123 outputs an error signal Ser1 when the amplitude signal Sap calculated with necessary accuracy and resolution exceeds the upper limit threshold signal Sup, and an error signal when the amplitude signal Sap is lower than the lower limit threshold signal Slo. Ser2 is output. As a result, the rotation angle detection circuit 101 can detect an abnormality such as a disconnection or a short circuit of the analog circuit unit or a sensor failure. For example, when a Hall element is used as a sensor for detecting rotation, when the signal wiring of the Hall element is short-circuited with a power supply, “A” can detect a failure by determining an upper limit threshold value. Further, when the magnet provided close to the Hall element falls, “A” = 0, and the failure can be detected by determining the lower threshold. Even when a resolver is used, it is possible to detect a broken wire of the coil with the same configuration.

  FIG. 7 is a block diagram showing a schematic configuration of a rotation angle detection circuit 201 provided in a non-contact rotation angle sensor as a second related technique. As shown in FIG. 7, the rotation angle detection circuit 201 in the second related technology includes an IC circuit unit 203 and a motor control microcomputer 205. The rotation angle detection circuit 201 is a microcomputer for motor control based on the angle detection signal Sφ (n) calculated by the IC circuit unit 203 and the 12-bit cosine signal (SADox) and sine signal (SADoy) output from the IC circuit unit. The angle detection signal Sθ (n) calculated in 205 is compared to determine whether or not the angle detection signal Sφ (n) is a correct value.

  The IC circuit unit 203 is a 12-bit analog output signal output from the X Hall element 203a and the Y Hall element 203b that detects changes in the magnetic field accompanying rotation of a motor (not shown), and the X and Y Hall elements 203a and 203b. An AD conversion circuit 203c that performs AD conversion to a digital value, and a digital angle calculation circuit 203d that receives a digital signal output from the AD conversion circuit 203c are included. The AD conversion circuit 203c is a 12-bit successive approximation AD conversion circuit.

  The motor control microcomputer 205 is provided in the IC circuit unit 203, a digital angle calculation circuit 205a to which a digital signal output from the AD conversion circuit 203c is input, an angle detection signal Sθ (n) calculated by the digital angle calculation circuit 205a. And a comparison circuit 205b that compares the angle detection signal Sφ (n) calculated by the digital angle calculation circuit 203d. The digital angle calculation circuit 205a has the same configuration as the digital angle calculation circuit 203d.

  For example, assume that the IC circuit unit 203 of the non-contact rotation angle sensor functions normally and tries to determine whether or not the angle detection signal Sφ (n) is a correct value. In the rotation angle detection circuit 201, in addition to the angle detection signal Sφ (n) detected by the digital angle calculation circuit 203d, the motor control microcomputer 205 is based on the 12-bit digital signals SADox and SADoy output from the successive approximation AD circuit 203c. The angle detection signal Sθ (n) is calculated by the digital angle calculation circuit 205a provided in the above. Further, the rotation angle detection circuit 201 compares the angle detection signal Sφ (n) calculated by the digital angle calculation circuit 203d with the angle detection signal Sθ (n) calculated by the digital angle calculation circuit 205a by the comparison circuit 205b. In addition, it is determined whether or not the angle detection signal Sφ (n) is a correct value. Thus, the rotation angle detection circuit 201 can determine whether or not the digital angle calculation circuit 203d is out of order.

Further, the output signal SHox output from the X Hall element 203a is A · cos θ, and the output signal SHoy output from the Y Hall element 203b is an analog voltage value expressed by A · sin θ, but the output signal SHox and the output signal Shoy are In reality, this is a signal to which an error or offset inherent in detection sensitivity is added due to semiconductor manufacturing variations or aging of magnets and IC circuits. Therefore, if the offset of the X Hall element 203a is Offx, the offset of the Y Hall element 203b is Offy, the detection sensitivity of the X Hall element 203a is Ax, and the detection sensitivity of the Y Hall element 203b is Ay, the output signal SHox and The output signal SHoy can be expressed by the following equations (3) and (4).
SHox = Ax · cos θ + Offx (3)
SHoy = Ay · sin θ + Offy (4)

When a 1% mismatch occurs between the detection sensitivity Ax and the detection sensitivity Ay of the X Hall element 203a and the Y Hall element 203b, the angle error generated in the angle detection signal Sφ (n) The angular position is about 0.3 ° (= 45 ° − (tan ⁻¹ ((0.99 × sin45 °) / (1.00 × cos45 °)))), which is less than the angular position of the actual motor. The angle is detected with a 3 ° offset. Further, when an offset of 1% is added to the detection sensitivity Ay, the angle error caused by the angle detection signal Sφ (n) due to this offset is about −0.6 ° (= 0 at the angular position of the motor near 0 °. °-(tan ⁻¹ ((1.00 × sin 0 ° + 0.01) / (1.00 × cos 0 °)))). In addition to manufacturing variations, such errors in the angle detection signal increase due to aging of magnets and semiconductors in the case of Hall elements, and in the case of resolvers also increase due to aging of the resistance of the coils constituting the resolver. . In order to detect (or correct) a minor failure such as an error in the angle detection signal due to such a secular change, it is necessary to examine in advance a detection sensitivity mismatch or offset. In addition, since detection sensitivity mismatch and offset actually include errors in the AD conversion circuit in addition to the Hall elements, it is desirable to calculate based on the SADox signal and SADoy signal obtained by AD-converting the SHox signal and SHoy signal. . In the second related art configuration, a 12-bit successive approximation AD converter circuit is used for the AD converter circuit, and the SADox signal and SADooy signal converted into a 12-bit digital value are outside the IC circuit. By calculating the detection sensitivity mismatch and offset, it is possible to detect a fine failure such as an increase in the angle detection signal error.

  However, the detailed detection of failure such as the failure detection of the digital angle calculation circuit by the second related technology and the increase of the error of the angle detection signal with the aging change is the configuration of the related technology using the first ΔΣ AD conversion circuit. Not applicable. The rotation angle detection circuit 101 using the ΔΣ AD conversion circuit as the AD conversion circuit becomes a signal obtained by modulating the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy by 1 bit. Therefore, the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy are rectangular high-frequency signals as shown in the lower part of FIG. For this reason, even if the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy are directly detected, effective information cannot be obtained from the detected signals. As a result, when the rotation angle detection circuit 101 cannot directly detect the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy, the rotation angle detection circuit 101 cannot cope with the failure detection of the digital circuit unit of the non-contact rotation angle sensor, and the angle detection signal Sφ (n ), An increase in the error of the fine angle detection signal accompanying the secular change cannot be detected.

  On the other hand, the rotation angle detection circuit 10 provided in the non-contact rotation angle sensor 1 according to the present embodiment has a multiplexer circuit 23. The multiplexer circuit 23 outputs the validation data Dmdv and the invalidation data Dmdi to the inner product calculation circuit 19 when the non-contact rotation angle sensor 1 is in the inspection mode. The non-contact rotation angle sensor 1 according to the present embodiment inputs the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy detected directly from the XΔΣ AD conversion circuit 7 and the YΔΣ AD conversion circuit 9 to the inner product calculation circuit 19 and validates them by the inner product calculation circuit 19. Based on the inner product data Dsp obtained by calculating the inner product of the data Dmdv, the invalidation data Dmdi, the XΔΣ modulation signal Smdx, and the YΔΣ modulation signal Smdy, smoothing is performed by a common digital filter circuit, and “A”, “A · cos θ”, A digital signal converted into 12 bits of “A · sin θ” can be obtained. For this reason, the non-contact rotation angle sensor 1 can detect the failure of the digital part of the rotation angle detection circuit 10 and the angle detection accompanying the secular change in addition to the failure detection of the analog circuit part and the sensor part with only a few additional circuits. It is possible to cope with fine failure detection such as an increase in signal error.

  In order to solve this problem, a ΔΣ AD conversion circuit that converts an output signal output from the X Hall element 203a and the Y Hall element 203b into a 1-bit modulated XΔΣ modulation signal and a YΔΣ modulation signal, and the XΔΣ modulation signal and A method is also conceivable in which a dedicated digital filter circuit for smoothing and bit extension of the YΔΣ modulation signal is provided. However, the digital filter circuit requires many digital circuits having a large area such as a register (storage device) and a full adder (adder). For this reason, the increase in the digital filter circuit causes an increase in the circuit area of the IC circuit unit 203. This increase in circuit area leads to an increase in IC chip cost of the non-contact rotation angle sensor and an increase in IC failure probability.

  On the other hand, the non-contact rotation angle sensor 1 according to the present embodiment is configured to adjust the output of the inner product calculation circuit in three ways by including the multiplexer circuit 23, and is converted into a 12-bit digital value. “A”, “A · cos θ”, and “A · sin θ” can all be calculated by a common digital filter circuit. Therefore, it is possible to cope with all of the failure detections described in the related art with only a few additional circuits without providing a plurality of digital filter circuits that lead to an increase in circuit area and failure probability.

[Second Embodiment]
A non-contact rotation angle sensor according to a second embodiment of the present invention will be described with reference to FIGS. 8 to 12 while referring to FIG.
The non-contact rotation angle sensor according to the present embodiment is characterized in that a loop filter of a digital angle calculation circuit is used as a digital filter used for bit expansion of a 1-bit X and YΔΣ modulation signal to 12 bits. Yes. The non-contact rotation angle sensor according to this embodiment has the same appearance as the non-contact rotation angle sensor 1 according to the first embodiment shown in FIG. FIG. 8 is a block diagram showing a schematic circuit configuration of the rotation angle detection circuit 51 provided in the non-contact rotation angle sensor according to the present embodiment. In addition, the same code | symbol is attached | subjected to the component which show | plays the function and effect | action similar to the non-contact rotation angle sensor 1 by the said 1st Embodiment, and the description is abbreviate | omitted.

  As shown in FIG. 8, the rotation angle detection circuit 51 includes an X Hall element 3 that detects an X axis component of a magnetic field based on a rotation angle of a rotor (not shown), and a Y axis component of a magnetic field based on the rotation angle of the rotor. And a Y Hall element 5 for detecting. The X-axis component of the magnetic field detected by the X Hall element 3 is a component in the X-axis direction shown in FIGS. 1 (a) and 1 (b). The Y-axis component of the magnetic field detected by the Y Hall element 5 is a component in the Y-axis direction shown in FIGS. 1 (a) and 1 (b). The rotation angle detection circuit 10 also outputs an XΔΣ AD conversion circuit (first ΔΣ modulation) that outputs an XΔΣ modulation signal (an example of a first ΔΣ modulation signal) Smdx corresponding to the X-axis component of the magnetic field detected by the X Hall element 3. An example of a circuit) 7 and a YΔΣ AD conversion circuit (second ΔΣ modulation circuit) that outputs Smdy according to a YΔΣ modulation signal (an example of a second ΔΣ modulation signal) corresponding to the Y-axis component of the magnetic field detected by the Y Hall element 5 9.

  The rotation angle detection circuit 51 receives an angle signal and outputs a cosine data ROM (an example of a cosine / sine data output unit) 11 that outputs cosine data and sine data according to the input angle signal, and X and YΔΣ AD conversion. A multiplexer circuit (an example of a selection circuit) 53 to which X and YΔΣ modulation signals Smdx and Smdy output from the circuits 7 and 9 and cosine data and sine data output from the sine wave data ROM 11 are input, and a signal output from the multiplexer circuit 53 Is input to the outer product calculation circuit 55. Further, the rotation angle detection circuit 51 includes a predetermined value signal generation circuit 61 that generates two types of predetermined value signals, and a control signal generation circuit 59 that generates a control signal Sc to be output to the multiplexer circuit 23.

  The sine wave data ROM 11 outputs 12-bit cosine data and sine data according to the input angle signal. The angle signal input to the sine wave data ROM 11 is an angle detection signal Sφ (n) output from an integration circuit 63 described later. The sine wave data ROM 11 outputs cosine data Dcos and sine data Dsin corresponding to the angle φ (n) represented by the input angle detection signal Sφ (n) to the multiplexer circuit 53.

  The multiplexer circuit 53 includes a first multiplexer circuit (an example of a first multiplexer) 53a and a second multiplexer circuit (an example of a second multiplexer) 53b. The first multiplexer circuit 53a includes 1-bit XΔΣ modulation signals Smdx and Smdy output from the XΔΣ AD conversion circuit 7 and the YΔΣ AD conversion circuit 9, respectively, and a predetermined value signal (data having a predetermined value) output from the predetermined value signal generation circuit 61. Example) Scnt1 inputs. The first multiplexer circuit 53a selects the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy and outputs them as the first data D1 and the second data D2, respectively, when the operation state of the non-contact rotation angle sensor is the use mode. It is like that. The first multiplexer circuit 53a selects one of the XΔΣ modulation signal Smdx and the YΔΣ modulation signal Smdy and selects the first data D1 and the second data when the operation state of the non-contact rotation angle sensor is in the inspection mode. It outputs as one of D2 and outputs a predetermined value signal Scnt1 as the other of the first data D1 and the second data D2. The first data D1 output from the first multiplexer circuit 53a is output to the first input terminal Icp1 of the outer product operation circuit 55, and the second data D2 output from the first multiplexer circuit 53a is the second input of the outer product operation circuit 55. It is output to the terminal Icp2.

  The second multiplexer circuit 53b includes cosine data Dcos and sine data Dsin output from the sine wave data ROM 11, a predetermined value signal (an example of data having a predetermined value) Scnt2 output from the predetermined value signal generation circuit 61, and an integration circuit. An angle detection signal Sφ (n) output from 63 is input. The second multiplexer circuit 53b selects cosine data Dcos and sine data Dsin and outputs them as third data D3 and fourth data D4, respectively, when the operation state of the non-contact rotation angle sensor is the use mode. Further, the second multiplexer circuit 53b selects the third data D3 and the fourth data D3 by selecting an angle detection signal (an example of an integration signal) Sφ (n) when the operation state of the non-contact rotation angle sensor is in the inspection mode. One of the data D4 is output, and the predetermined value signal Scnt2 is output as the other of the third data D3 and the fourth data D4. The third data D3 output from the second multiplexer circuit 53b is output to the third input terminal Icp3 of the outer product operation circuit 55, and the fourth data D4 output from the second multiplexer circuit 53b is the fourth input of the outer product operation circuit 55. It is output to the terminal Icp4. In FIG. 8 and FIGS. 11 to 13 to be described later, the first to fourth input terminals Icp1, Icp2, Icp3, and Icp4 are shown with only the numerical values of the respective input terminals by omitting the letters “Icp”.

The control signal Sc output from the control signal generation circuit 59 has information indicating whether the non-contact rotation angle sensor is currently in the use mode or the inspection mode. For example, when the value of the control signal Sc is “0”, it is determined that the operation state of the non-contact rotation angle sensor is the use mode, and when the value of the control signal Sc is “1” or “2”, the non-contact rotation is performed. It is determined that the operating state of the angle sensor is the inspection mode.
The predetermined value signal Scnt1 generated by the predetermined value signal generation circuit 61 is, for example, 1LSB, and the predetermined value signal Scnt2 is, for example, 2 ¹² LSB.

  The outer product calculation circuit 55 calculates the angle error signal (an example of outer product data) by calculating the outer product of the first data D1 and the second data D2 output from the multiplexer circuit 53, and the third data D3 and the fourth data D4. ) Sae is output. The angle error signal Sae is output from an output terminal Ocp provided in the outer product calculation circuit 55. The outer product calculation executed by the outer product calculation circuit 55 can be expressed by the above-described equation (1).

The rotation angle detection circuit 51 integrates the phase compensation circuit 15 to which the angle error signal Sae output from the outer product calculation circuit 55 is input and the angle error signal Sae output from the phase compensation circuit 15 to obtain the angle detection signal Sφ (n). And an integration circuit (an example of an integration signal output unit) 63 for outputting.
The integration circuit 63 outputs the angle detection signal Sφ (n) to the second multiplexer circuit 53b and the sine wave data ROM 11.

  The rotation angle detection circuit 51 selectively switches the signal output from the multiplexer circuit 53 depending on whether the operation state of the non-contact rotation angle sensor is the use mode or the inspection mode, and switches the closed loop formed by the digital angle calculation circuit 52. It has become. When the operation state of the non-contact rotation angle sensor is the use mode, the digital angle calculation circuit 52 forms a closed loop L2 by the outer product calculation circuit 55, the phase compensation circuit 15, the integration circuit 63, the sine wave data ROM 11, and the multiplexer circuit 53. On the other hand, when the operation state of the non-contact rotation angle sensor is the inspection mode, the digital angle calculation circuit 52 forms a closed loop L3 with the outer product calculation circuit 55, the phase compensation circuit 15, the integration circuit 63, and the multiplexer circuit 53.

  Next, centering on the operation of the multiplexer circuit 53, the operation of the non-contact rotation angle sensor according to the present embodiment will be described with reference to FIGS. FIG. 9 is an output signal selection table showing the relationship between the value of the control signal Sc input to the multiplexer circuit 53 and the output signal output from the output terminal of the multiplexer circuit 53. 9A shows an output signal selection table T1 for the first multiplexer circuit 53a, and FIG. 9B shows an output signal selection table T2 for the second multiplexer circuit 53b. The output signal selection table T1 is stored in a predetermined storage unit (not shown) provided in the first multiplexer circuit 53a, and the output signal selection table T2 is a predetermined storage unit provided in the second multiplexer circuit 53b. (Not shown).

  As shown in FIG. 9A, the output signal selection table T1 is divided into two fields, a “control signal” column and an “output signal” column. The “control signal” indicates the control signal Sc generated by the control signal generation circuit 59 and input to the first multiplexer circuit 53a. “Output signal” indicates an output signal output from the first multiplexer circuit 53a. The “output signal” field is divided into two fields, a “D1” field and a “D2” field. “D1” indicates the first data D1 output from the first output terminal Omp11 of the first multiplexer circuit 53a, and “D2” indicates the second data output from the second output terminal Opm12 of the first multiplexer circuit 53a. Data D2 is shown. In the “control signal” column, possible values “0”, “1”, and “2” of the control signal Sc are stored. In the “D1” column and the “D2” column, the types of output signals respectively output from the first and second output terminals Omp11 and Omp12 as the first and second data D1 and D2 according to the value of the control signal Sc. Is stored.

  As shown in FIG. 9B, the output signal selection table T2 is divided into two fields, a “control signal” column and an “output signal” column. “Control signal” indicates the control signal Sc generated by the control signal generation circuit 59 and input to the second multiplexer circuit 53b. “Output signal” indicates an output signal output from the second multiplexer circuit 53b. The “output signal” field is divided into two fields, a “D3” field and a “D4” field. “D3” indicates the third data D3 output from the first output terminal Omp21 of the second multiplexer circuit 53b, and “D4” indicates the fourth data output from the second output terminal Opm22 of the second multiplexer circuit 53b. Data D4 is shown. In the “control signal” column, possible values “0”, “1”, and “2” of the control signal Sc are stored. In the “D3” column and the “D4” column, the types of output signals output from the first and second output terminals Omp21, Omp22 as the third and fourth data D3, D4 according to the value of the control signal Sc, respectively. Is stored.

  FIG. 10 is a diagram illustrating an operation state of the multiplexer circuit 53 when the value of the control signal Sc is “0”. FIG. 11 is a diagram illustrating an operation state of the multiplexer circuit 53 when the value of the control signal Sc is “1”. FIG. 12 is a diagram illustrating an operation state of the multiplexer circuit 53 when the value of the control signal Sc is “2”.

First, the operation of the non-contact rotation angle sensor when the operation state of the non-contact rotation angle sensor is the use mode and the value of the control signal Sc is “0” will be described.
The rotation angle detection circuit 51 detects changes in the magnetic field accompanying the rotation of the rotor by the X Hall element 3 and the Y Hall element 5. Next, the rotation angle detection circuit 51 converts the analog output signals SHox and SHoy output from the X and Y Hall elements 3 and 5 into X and Y modulation signals which are 1-bit digital signals by the X and YΔΣ AD conversion circuits 7 and 9. The data is converted into Smdx and Smdy and output to the first multiplexer circuit 53a.

  As shown in FIG. 9A, in the output signal selection table T1, “Smdx” is stored in the “D1” field and “Smdx” is stored in the “D2” field, corresponding to “0” in the “control signal” field. "Smdy" is stored. Therefore, as shown in FIG. 10, the first multiplexer circuit 53 a selects the X and Y modulation signals Smdx and Smdy input from the X and YΔΣ AD conversion circuits 7 and 9. Then, the first multiplexer circuit 53a outputs the X modulation signal Smdx as the first data D1 from the first output terminal Omp11, and outputs the Y modulation signal Smdy as the second data D2 from the second output terminal Opm12.

  Further, as shown in FIG. 9B, in the output signal selection table T2, “Dcos” is stored in the “D3” field corresponding to “0” in the “control signal” field, and the “D4” field. Stores “Dsin”. For this reason, as shown in FIG. 10, the second multiplexer circuit 53b selects the cosine data Dcos and the sine data Dsin input from the sine wave data ROM 11. Then, the second multiplexer circuit 53b outputs the cosine data Dcos as the third data D3 from the first output terminal Omp21, and outputs the sine data Dsin as the fourth data D4 from the second output terminal Opm22.

  The outer product calculation circuit 55 calculates the outer product of the signal input to the first and second input terminals Isp1 and Isp2 and the input signal input to the third and fourth input terminals Isp3 and Isp4 based on the above equation (1). The cross product data Dcp is calculated. The XΔΣ modulation signal Smdx input to the first input terminal Isp1 is “A · cos θ (1 bit)”, the YΔΣ modulation signal Smdy input to the second input terminal Isp2 is “A · sin θ (1 bit)”, and the third The cosine data Dcos input to the input terminal Isp3 is “cos (φ (n))”, and the sine data Dsin input to the fourth input terminal Isp4 is “sin (φ (n))”. A · cos θ (1 bit) and A · sin θ (1 bit) in the X and YΔΣ modulation signals Smdx and Smdy are 1-bit data. In this case, from the equation (1), the outer product data Dcp is “A · sin (φ (n) −θ)” (= A · cos θ × sin (φ (n)) − A · sin θ × cos (φ (n ))). That is, the angle error signal “A × (φ (n) −θ)” is obtained by calculating the outer product data Dcp. Due to the closed loop characteristics of the digital angle calculation circuit 52, the angle error signal “φ (n) −θ”, which is the outer product data Dcp output from the outer product calculation circuit 55, is fed back so as to converge to “0”. Thus, the rotation angle detection circuit 51 can detect φ (n) equal to the rotation angle θ of the rotor as the angle detection signal Sφ (n) output via the phase compensation circuit 15 and the integration circuit 63.

Next, the operation of the non-contact rotation angle sensor when the operation state of the non-contact rotation angle sensor is the inspection mode and the value of the control signal Sc is “1” will be described.
The rotation angle detection circuit 51 detects changes in the magnetic field accompanying the rotation of the rotor by the X Hall element 3 and the Y Hall element 5. Next, the rotation angle detection circuit 51 converts the analog output signals SHox and SHoy output from the X and Y Hall elements 3 and 5 into X and Y modulation signals which are 1-bit digital signals by the X and YΔΣ AD conversion circuits 7 and 9. The data is converted into Smdx and Smdy and output to the first multiplexer circuit 53a.

  As shown in FIG. 9A, in the output signal selection table T1, “Smdx” is stored in the “D1” column and “Smdx” is stored in the “D2” column corresponding to “1” in the “control signal” column. "Scnt1" is stored. For this reason, as shown in FIG. 11, the first multiplexer circuit 53 a selects the X modulation signal Smdx input from the XΔΣ AD conversion circuit 7 and the predetermined value signal Scnt input from the predetermined value signal generation circuit 61. Then, the first multiplexer circuit 53a outputs the X modulation signal Smdx as the first data D1 from the first output terminal Omp11, and outputs the Y modulation signal Smdy as the second data D2 from the second output terminal Opm12.

  Also, as shown in FIG. 9B, in the output signal selection table T2, “Sφ (n)” is stored in the “D3” column corresponding to “1” in the “control signal” column, and “D4” "Scnt2" is stored in the "" column. Therefore, as shown in FIG. 11, the second multiplexer circuit 53 b selects the angle detection signal Sφ (n) input from the integration circuit 63 and the predetermined value signal Scnt 2 input from the predetermined value signal generation circuit 61. Then, the second multiplexer circuit 53b outputs the angle detection signal Sφ (n) as the third data D3 from the first output terminal Omp21, and outputs the predetermined value signal Scnt2 as the fourth data D4 from the second output terminal Opm22. To do.

The outer product calculation circuit 55 calculates the outer product of the signal input to the first and second input terminals Isp1 and Isp2 and the input signal input to the third and fourth input terminals Isp3 and Isp4 based on the above equation (1). The cross product data Dcp is calculated. The XΔΣ modulation signal Smdx input to the first input terminal Isp1 is “A · cos θ (1 bit)”, the predetermined value signal Scnt1 input to the second input terminal Isp2 is “1LSB”, and is input to the third input terminal Isp3. The angle detection signal Sφ (n) is “Sout”, and the predetermined value signal Scnt2 input to the fourth input terminal Isp4 is “2 ¹² LSB”. A · cos θ (1 bit) in the XΔΣ modulation signal Smdx is 1-bit data. From equation (1), the outer product data Dcp is “A · cos θ (1 bit) × 2 ¹² LSB−1 × Sout”. Due to the characteristic of the closed loop L3 of the digital angle calculation circuit 52, the cross product data Dcp output from the cross product calculation circuit 55 is fed back so as to converge to “0” as indicated by the broken line shown at the upper right in FIG. As a result, the angle detection signal Sφ (n) is smoothed by the loop filter characteristic of the closed loop L3 of the digital angle calculation circuit 52, so that the average value of the binary signal of A · cos θ (1 bit) × 2 ¹² LSB is obtained. Converge to. As a result, the rotation angle detection circuit 51 can detect “A · cos θ” that is bit-extended to 12 bits as the angle detection signal Sφ (n) output through the phase compensation circuit 15 and the integration circuit 63.

Next, the operation of the non-contact rotation angle sensor when the operation state of the non-contact rotation angle sensor is the inspection mode and the value of the control signal Sc is “2” will be described.
The rotation angle detection circuit 51 detects changes in the magnetic field accompanying the rotation of the rotor by the X Hall element 3 and the Y Hall element 5. Next, the rotation angle detection circuit 51 converts the analog output signals SHox and SHoy output from the X and Y Hall elements 3 and 5 into X and Y modulation signals which are 1-bit digital signals by the X and YΔΣ AD conversion circuits 7 and 9. The data is converted into Smdx and Smdy and output to the first multiplexer circuit 53a.

  As shown in FIG. 9A, in the output signal selection table T1, “Scnt1” is stored in the “D1” column and “Snt1” is stored in the “D2” column, corresponding to “2” in the “control signal” column. "Smdy" is stored. Therefore, as shown in FIG. 12, the first multiplexer circuit 53a selects the predetermined value signal Scnt1 input from the predetermined value signal generation circuit 61 and the Y modulation signal Smdy input from the YΔΣ AD conversion circuit 9, and outputs the first output terminal. The predetermined value signal Scnt1 is output from the Omp11 as the first data D1, and the Y modulation signal Smdy is output from the second output terminal Opm12 as the second data D2.

  Further, as shown in FIG. 9B, in the output signal selection table T2, “Scnt2” is stored in the “D3” column corresponding to “2” in the “control signal” column, and the “D4” column. Stores “Sφ (n)”. Therefore, as shown in FIG. 12, the second multiplexer circuit 53b selects the predetermined value signal Scnt2 input from the predetermined value signal generation circuit 61 and the angle detection signal Sφ (n) input from the integration circuit 63, The predetermined value signal Scnt2 is output as the third data D3 from the first output terminal Omp21, and the angle detection signal Sφ (n) is output as the fourth data D4 from the second output terminal Opm22.

The outer product calculation circuit 55 calculates the outer product of the signal input to the first and second input terminals Isp1 and Isp2 and the input signal input to the third and fourth input terminals Isp3 and Isp4 based on the above equation (1). The cross product data Dcp is calculated. The predetermined value signal Scnt1 input to the first input terminal Isp1 is set to “1LSB”, the YΔΣ modulation signal Smdy input to the second input terminal Isp2 is set to “A · sin θ (1 bit)”, and is input to the third input terminal Isp3. The predetermined value signal Scnt2 is “2 ¹² LSB”, and the angle detection signal Sφ (n) input to the fourth input terminal Isp4 is “Sout”. A · sin θ (1 bit) in the YΔΣ modulation signal Smdy is 1-bit data. From the expression (1), the outer product data Dcp is “1 × Sout−A · sin θ (1 bit) × 2 ¹² LSB”. Due to the characteristics of the closed loop L3 of the digital angle calculation circuit 52, the outer product data Dcp output from the outer product calculation circuit 55 is fed back so as to converge to “0”. As a result, the angle detection signal Sφ (n) is smoothed by the characteristics of the loop filter, and thus converges to the average value of the binary signal of A · sin θ (1 bit) × 2 ¹² LSB. As a result, the rotation angle detection circuit 51 can detect “A · sin θ” which is bit-extended to 12 bits as the angle detection signal Sφ (n) output via the phase compensation circuit 15 and the integration circuit 63.

  As described above, in the non-contact rotation angle sensor according to the present embodiment, the digital filter used to extend the 1-bit X and YΔΣ modulation signal to 12 bits is a digital filter provided for performing angle calculation. It is a loop filter of the closed loop L3 of the angle calculation circuit 52. Therefore, as in the first embodiment, a digital filter circuit having a large circuit area is not required, and a 1-bit X and YΔΣ modulation signal is converted to 12 bits by simply adding a multiplexer circuit with a simple configuration. Can be output.

  The loop filter in the rotation angle detection circuit generally has a low-pass filter characteristic in a band of about 1 kHz. For this reason, the non-contact rotation angle sensor according to the present embodiment can easily realize a filter characteristic that suppresses noise with a simple configuration as compared to the non-contact rotation angle sensor 1 according to the first embodiment. When using a rotation angle detection device for motor control applications, disturbance electromagnetic noise (megahertz high-frequency noise) may be mixed in signals from Hall elements and the like. The non-contact rotation angle sensor according to the present embodiment can accurately detect the 12-bit rotation angle in this case as well.

The present invention is not limited to the above embodiment, and various modifications can be made.
In the first and second embodiments, the Hall element is provided as a magnetic sensor for detecting the rotation angle. However, the present invention can also be applied to a rotation angle detection apparatus using an MR element or a resolver.

DESCRIPTION OF SYMBOLS 1 Non-contact rotation angle sensor 3,103,203a X Hall element 3a 1st X Hall element 3b 2nd X Hall element 5,105,203b Y Hall element 3a 1st Y Hall element 3b 2nd Y Hall element 7,107 XΔΣ conversion circuit 9, 109 YΔΣ conversion circuit 10, 51, 101, 201 Rotation angle detection circuit 12, 52, 102, 203d, 205a Digital angle calculation circuit 13, 55, 113 Outer product calculation circuit 15, 37, 115 Phase compensation circuit 17, 39, 63, 117 integration circuit 19, 119 inner product calculation circuit 21, 121 digital filter circuit 23, 53 multiplexer circuit 25, 59 control signal generation circuit 27 validation / invalidation data generation circuit 29 IC package 31 rotor 31a output shaft 31b permanent magnet 33 amplification circuit 35 Adder / Subtractor 53a First multiplexer Path 53a Second multiplexer circuit 61 Predetermined value signal generation circuit 123 Threshold determination circuit 203 IC circuit unit 203c ΔΣ AD conversion circuit 205 Motor control microcomputer 205b Comparison circuit

Claims (3)

An X-axis component detector that detects an X-axis component of the magnetic field based on the rotation angle of the rotor;
A Y-axis component detector that detects a Y-axis component of the magnetic field;
A first ΔΣ modulation circuit that outputs a first ΔΣ modulation signal corresponding to the X-axis component;
A second ΔΣ modulation circuit that outputs a second ΔΣ modulation signal corresponding to the Y-axis component;
A cosine / sine data output unit that receives an angle signal and outputs cosine data and sine data according to the angle signal;
An outer product calculation circuit for calculating outer product data of the first ΔΣ modulation signal and the second ΔΣ modulation signal and the cosine data and the sine data;
An angle signal output unit for integrating the outer product data and outputting the angle signal;
An inner product calculation circuit for calculating inner product data of the first ΔΣ modulation signal and the second ΔΣ modulation signal and first data and second data;
A digital filter for smoothing and outputting the inner product data;
In the use mode, the cosine data and the sine data are selected and output as the first data and the second data, respectively, and in the inspection mode, the first ΔΣ modulation signal and the second data are output. A selection circuit that selects the third data and the fourth data that enable one of the ΔΣ modulation signals and disables the other, and outputs them as the first data and the second data, respectively;
A non-contact rotation angle sensor. An X-axis component detector that detects an X-axis component of the magnetic field based on the rotation angle of the rotor;
A Y-axis component detector that detects a Y-axis component of the magnetic field;
A first ΔΣ modulation circuit that outputs a first ΔΣ modulation signal corresponding to the X-axis component;
A second ΔΣ modulation circuit that outputs a second ΔΣ modulation signal corresponding to the Y-axis component;
An outer product calculation circuit for calculating outer product data of the first data, the second data, the third data, and the fourth data;
An integration signal output unit for outputting an integration signal of the outer product data;
A cosine / sine data output unit that receives an angle signal and outputs cosine data and sine data according to the angle signal;
In the use mode, the first ΔΣ modulation signal, the second ΔΣ modulation signal, the cosine data, and the sine data are selected, and the first data, the second data, and the third data are selected. Data and the fourth data, respectively, and in the inspection mode, the first ΔΣ modulation signal or the second ΔΣ modulation signal is selected and looped together with the outer product calculation circuit and the integration signal output unit A selection circuit for forming and smoothing the filter;
A non-contact rotation angle sensor. The selection circuit includes:
In the use mode, the first ΔΣ modulation signal and the second ΔΣ modulation signal are selected and output as the first data and the second data, respectively, and in the inspection mode, the One of the first ΔΣ modulation signal and the second ΔΣ modulation signal is selected and output as one of the first data and the second data, and data having a predetermined value is selected and the first data is selected. A first multiplexer that outputs the other of the first data and the second data;
In the use mode, the cosine data and the sine data are selected and output as the third data and the fourth data, respectively, and in the inspection mode, the integration signal is selected and the first data is selected. A second multiplexer that outputs as one of the third data and the fourth data, selects data having a predetermined value, and outputs the selected data as the other of the third data and the fourth data;
The non-contact rotation angle sensor according to claim 2, comprising:

Images