JP2015121424A - Magnetic element control device, magnetic element control method, and magnetic detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic element control device suppressing off-set temperature characteristics of an operational amplifier which cannot be removed by a chopping operation.SOLUTION: The magnetic element control device of the present invention has a magnetic material core including an exciting coil and a detection coil, and detects a magnetic field intensity applied to a magnetic element by a magnetic balance method. The magnetic element control device comprises: an excitation signal adjustment unit that generates an excitation signal to be applied to the exciting coil from an alternation current signal generated from an alternation signal; a detection signal amplification unit that amplifies a positive/negative voltage generated when the electric current direction of the excitation signal is switched, to obtain a detection signal; a detection signal comparison unit that detects a time width of the detection signal; a feedback signal adjustment unit that generates a feedback signal for cancelling a steady magnetic field from voltage information indicating the time width; and a data signal conversion unit that outputs the feedback signal as a data signal indicating the magnetic field intensity. The data signal conversion unit inverts or non-inverts the polarity of an input signal of each differential amplifier of the excitation signal adjustment unit, the detection signal amplification unit and the feedback signal adjustment unit, and generates the data signal from combination thereof.

Description

  The present invention relates to a signal processing circuit and a physical quantity measuring apparatus using the circuit, and in particular, a magnetic element control device for driving a time-resolved fluxgate (hereinafter referred to as FG) magnetic element, and a magnetic element control. The present invention relates to a method and a magnetic detection device that detects a magnetic field using the method.

In general, FG magnetic elements have higher sensitivity to detect magnetic fields and can be miniaturized compared to other magnetic elements such as Hall elements and magnetoresistive elements. It is used for.
FIG. 15 is a diagram illustrating a configuration example of a time-resolved FG type magnetic element (magnetic field proportional measurement). In FIG. 15, in the FG magnetic element, an excitation winding and a detection winding are wound around the outer peripheral surface of a magnetic core made of a high permeability material. The region around which the excitation winding is wound functions as an excitation coil driven by the excitation signal, and the region around which the detection winding is wound functions as a detection coil that outputs a detection signal. By passing an excitation current through the excitation coil wound around the magnetic core, a detection signal is induced in the detection coil by mutual induction. The stationary magnetic field Hex is a magnetic field penetrating through the cylindrical space formed by the excitation winding and the detection winding of the magnetic core.

  FIG. 16 is a waveform diagram illustrating the principle of magnetic detection in a magnetic field proportional type using a time-resolved FG type magnetic element. Here, FIG. 16A is a diagram showing the excitation current supplied to the excitation coil of the magnetic element, where the vertical axis shows the current value of the excitation current and the horizontal axis shows the time. FIG. 16B is a diagram showing the magnetic flux density of the magnetic field generated in the magnetic core by the exciting coil of the magnetic element, the vertical axis shows the magnetic flux density in the magnetic core, and the horizontal axis shows the time. Yes. FIG. 16C is a diagram showing the voltage value of the pulse generated by the induced electromotive force in the detection coil of the magnetic element, the vertical axis shows the voltage value of the pickup voltage of the detection coil, and the horizontal axis shows the time. Yes.

In FIG. 16, in order to drive the exciting coil, a signal of the exciting current Id alternating between the terminals of the exciting coil (hereinafter referred to as an exciting signal), that is, a triangular wave shape as shown in FIG. The excitation signal (that is, the triangular wave current signal) is applied (for example, see Patent Document 1).
Thus, in the case of FIG. 16C, during the time when the direction of the excitation current changes (positive and negative alternating time zone of the excitation current), at time t1 and time t2, the detection coil has positive and negative pulses due to the induced electromotive force. (Pickup signal, ie, pu signal) is generated. Hereinafter, the voltage Vp (pickup voltage) of this pulse is used as a detection signal. This detection signal is generated between the terminals of the detection coil as a pulse having a positive and negative polarity voltage continuously corresponding to the period of the triangular wave current signal (see, for example, Patent Document 2 and Patent Document 3).

When a stationary magnetic field Hex (see FIG. 15) penetrating through the cylindrical space formed by the excitation winding and the detection winding of the magnetic core is applied to this magnetic element, the stationary current corresponding to this stationary magnetic field Hex in the excitation winding. Flows. That is, the above-described steady current is superimposed as an offset on the excitation current Id of the excitation signal applied to the excitation winding.
As a result, the driving state of the exciting coil changes due to the alternating excitation signal due to this offset, that is, the time when the direction in which the exciting current Id flows changes when the stationary magnetic field Hex is applied and when the stationary magnetic field Hex is It varies depending on whether it is not applied.

  At this time, as shown in FIG. 16C, the stationary magnetic field Hex is applied in the same direction as the magnetic field generated by the exciting coil as compared with the case where the stationary magnetic field Hex is not applied (Hex = 0). In the case of (Hex> 0), the time t1, which is the timing at which the direction in which the excitation current Id flows, is delayed, and the time t2 is advanced (time Tm is shorter than T / 2). On the other hand, when the stationary magnetic field Hex in the direction opposite to the magnetic field generated by the exciting coil is applied (Hex <0), the direction in which the exciting current Id flows changes as compared with the case where the stationary magnetic field Hex is not applied. At the timing, the time t1 becomes earlier and the time t2 becomes later (time Tp becomes longer than T / 2).

As a result, the change in the magnetic flux density φ in the magnetic core, which changes according to the timing at which the direction in which the excitation current Id flows, also changes corresponding to the steady current due to the steady magnetic field Hex superimposed on the excitation current Id. It will be.
When the direction of the magnetic flux changes, an induced electromotive force is generated in a direction that cancels the change of the magnetic flux with respect to the detection coil. Occur. On the other hand, the detection signal is generated as a positive voltage pulse at the timing when the excitation current Id changes from negative to positive.

As described above, the FG type magnetic element has a timing at which a detection signal is output when the stationary magnetic field Hex is not applied and a timing at which the detection signal is output when the stationary magnetic field Hex is applied. By comparison, the magnitude of the stationary magnetic field Hex can be indirectly measured. That is, when a steady magnetic field Hex is applied, a specific steady current flows in the drive coil, so that a constant offset is superimposed on the excitation signal, and the time interval between the negative and positive voltage pulse detection signals changes.
Therefore, the magnetic detection device using the FG type magnetic element measures the intensity of the stationary magnetic field Hex applied from the outside by measuring the time interval at which the negative and positive voltage pulse detection signals are generated. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3).

  Here, the maximum value of the excitation current Id applied to the excitation coil is set to a value that generates a magnetic field that is equal to or higher than the saturation magnetic flux density of the magnetic core. Thereby, the measurement magnetic field range of the magnetic element is theoretically determined from the current intensity of the excitation signal and the amount of superimposed voltage on the excitation signal with respect to the magnetic field change. Further, the magnetic field of the magnetic element is measured from the time of one cycle of the excitation signal and the time change corresponding to the current value of the steady current as an offset by applying the steady magnetic field Hex (hereinafter referred to as excitation efficiency). It is determined.

  That is, as shown in FIG. 16, the period from time t0 to time t3 is one period of the excitation signal, and the period width is time T. When the stationary magnetic field Hex is not applied (Hex = 0), a positive voltage detection signal (hereinafter referred to as second detection) from time t1 when a negative voltage detection signal (hereinafter referred to as first detection signal) is output. The time T0 until the time t2 when the signal is detected is a half period of the excitation signal, and thus becomes the time T / 2.

  In FIG. 16, when digital output is performed from a magnetic sensor, a time T0 that is an analog amount is converted into a unit representation of a digital signal at a constant time interval (hereinafter referred to as a TDC (Time to Digital Converter) circuit). ). In addition, by synchronizing the excitation signal generated by the TDC circuit and the digital-analog conversion circuit to the digital signal described above, the number of bits in the full range can be maintained even when the period of the excitation signal varies. is there. As a result, a driving method that obtains linearity with respect to a change in magnetic field with good output in a wide magnetic field range is used (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).

  In addition, when a stationary magnetic field Hex is applied, a time width (hereinafter referred to as a measurement time width) from when the first detection signal is output until the second detection signal is detected changes with respect to time T / 2. To do. Here, as shown in FIG. 16, when the magnetic flux direction of the stationary magnetic field Hex is a solid arrow (Hex> 0), the time width Tm is determined from the time T / 2 because the direction is the same as the magnetic flux direction generated by the exciting coil. On the other hand, when the magnetic flux direction of the stationary magnetic field Hex is a dashed arrow (Hex <0), the time width Tp is the time T / 2 because the direction is opposite to the magnetic flux direction generated by the exciting coil. It becomes longer (Tp> T0). Here, T0 = T / 2.

Next, FIG. 17 is a schematic block diagram showing a configuration example of a magnetic detection device using a magnetic element control device in magnetic field proportional control using a time-resolved FG type magnetic element. In FIG. 17, a magnetic element 50 is the magnetic element shown in FIG. 15, and includes a detection coil 51 (detection coil in FIG. 15) and an excitation coil 52 (excitation coil in FIG. 15).
The magnetic element control device 400 includes a magnetic element control unit 401, a clock signal generation unit 402, and a clock signal adjustment unit 403.
The clock signal generation unit 402 generates a clock with a period T and outputs it to the clock signal adjustment unit 403.
The clock signal adjustment unit 403 adjusts the signal level of the supplied clock and outputs the adjusted clock to the magnetic element control unit 401.

The magnetic element control unit 401 includes a detection signal amplification unit 4012, a detection signal comparison unit 4013, an output signal generation unit 4015, a data signal conversion unit 4016, an excitation signal adjustment unit 4017, and an excitation signal generation unit 4018.
The excitation signal generation unit 4018 generates, for example, a triangular wave that is an excitation signal shown in FIG. 19A from the clock supplied from the clock signal adjustment unit 403.
The excitation signal adjustment unit 4017 adjusts the voltage level of the excitation signal supplied from the excitation signal generation unit 4018 and supplies it to the excitation coil 52 as an excitation signal.

The exciting coil 52 generates a magnetic field corresponding to the triangular wave in the magnetic core of the magnetic element 50.
The detection coil 51 generates pulses in the positive and negative alternating time zones of the excitation signal in the magnetic core.
The detection signal amplification unit 4012 amplifies the voltage level of the pulse supplied from the detection coil 51 and outputs the amplified voltage level to the detection signal comparison unit 4013 as a detection signal.
The detection signal comparison unit 4013 obtains the difference between the time width of the pulse (detection signal) between time t1 and time t2 and T / 2, and outputs this difference to the output signal generation unit 4015.

The output signal generation unit 4015 obtains voltage information corresponding to the difference from the difference indicating the supplied time. The output signal generation unit 4015 outputs the obtained voltage information to the data signal conversion unit 4016.
The data signal conversion unit 4016 reads the magnetic field intensity corresponding to the voltage value of the voltage information from the voltage value magnetic field table previously written and stored in the internal storage unit, and the intensity of the magnetic field applied to the magnetic element 50 Ask for. The voltage value magnetic field table is a table showing the correspondence between the voltage value of the voltage information and the intensity of the applied stationary magnetic field Hex. A magnetic field intensity detection device (not shown) is connected to the data signal output terminal.

  Next, FIG. 18 is a diagram illustrating a configuration example of a time-resolved FG type magnetic element (magnetic field balance type measurement). As shown in FIG. 18, the magnetic element of the FG method in the magnetic field balance type measurement differs from the magnetic element of FIG. 15 in that the excitation winding and the detection winding are provided on the outer peripheral surface of the magnetic core made of a high permeability material. In addition to the wire, a feedback (hereinafter referred to as FB: feedback) winding is wound. The region where the excitation winding is wound functions as an excitation coil driven by the excitation signal, and the region where the detection winding is wound functions as a detection coil which outputs the detection signal, and the feedback winding is wound. The functioning area functions as a feedback (FB) coil driven by a feedback signal. The stationary magnetic field Hex is a magnetic field penetrating through a cylindrical space formed by the excitation winding and the detection winding of the magnetic core.

Next, FIG. 19 is a waveform diagram for explaining the principle of magnetic detection in magnetic field balance measurement using a time-resolved FG type magnetic element.
FIG. 19A shows the exciting current supplied to the exciting coil of the magnetic element, the vertical axis shows the current value of the exciting current, and the horizontal axis shows time. The exciting current is a positive / negative alternating signal with a reference current value of 0 A (zero ampere) as a boundary. FIG. 19B is a diagram illustrating an FB signal (that is, a feedback signal) that is a current applied to the feedback coil of the magnetic element, where the vertical axis indicates the current value of the FB signal, and the horizontal axis indicates time. . FIG. 19C is a diagram showing the voltage value of a pulse generated by the induced electromotive force in the detection coil of the magnetic element, the vertical axis shows the voltage value of the pickup signal, and the horizontal axis shows time.

As shown in FIG. 19, in the case of magnetic field balance type measurement, a magnetic field that cancels out a stationary magnetic field Hex applied to the magnetic element (a stationary magnetic field that passes through the magnetic core) is generated by the feedback coil. Then, the stationary magnetic field Hex applied to the magnetic element is measured from the current value when the feedback coil generates a magnetic field that cancels the stationary magnetic field.
In the magnetic field balance type, in addition to the excitation coil and the detection coil, the feedback coil is provided in the magnetic element as a coil for generating a magnetic field for canceling the stationary magnetic field in the magnetic core.
Hereinafter, in this specification, a method of applying a FB signal to cancel a stationary magnetic field in the magnetic core and measuring the magnetic field is referred to as FB (feedback) coil FB control.

In the case of magnetic field balance type measurement, the time interval of pulses generated in the detection coil is measured in the positive and negative alternating time zones of the excitation signal applied to the excitation coil, as in the magnetic field proportional expression already described. Based on the measurement result, the feedback coil is set so that the time from the time t1 at which the negative voltage detection signal is output to the time t2 at which the positive voltage detection signal is detected is T / 2. Apply FB signal.
For example, in FIG. 19C, when the time width between time t1 and time t2 becomes wider than T / 2, a stationary magnetic field Hex in the negative direction is applied as shown in FIG. This means that the waveform of the excitation signal has changed from the waveform L0 to the waveform L2. For this reason, in order to return the waveform L2 of the excitation signal to the position of the curve L0 where the time width between the time t1 and the time t2 is T / 2, the feedback coil is represented by the waveform FB2 in FIG. An FB signal having a current value is applied.

On the other hand, in FIG. 19C, when the time width between time t1 and time t2 becomes narrower than T / 2, a stationary magnetic field Hex in the positive direction is applied as shown in FIG. This means that the waveform of the excitation signal has changed from the waveform L0 to the waveform L1. Therefore, in order to return the waveform L1 of the excitation signal to the position of the waveform L0, an FB signal having a current value represented by the waveform FB1 in FIG. 19B is applied to the feedback coil. On the other hand, the stationary magnetic field Hex in the negative direction is applied, and the waveform of the excitation signal substantially changes from the waveform L0 to the waveform L2. Therefore, in order to return the waveform L2 of the excitation signal to the position of the waveform L0, an FB signal having a current value represented by the waveform FB2 in FIG. 19B is applied to the feedback coil.
Then, the strength of the stationary magnetic field applied to the magnetic element is obtained from the current value of the FB signal applied to the feedback coil so that the time width between time t1 and time t2 is T / 2.

Next, FIG. 20 is a block diagram illustrating a configuration example of a magnetic detection device using a magnetic element control device in feedback coil FB control. In FIG. 20, a magnetic element 300 is the magnetic element of FIG. 18, and includes an exciting coil 301, a feedback coil 302, and a detection coil 303.
The magnetic element control device 200 includes a magnetic element control unit 201, a clock signal generation unit 202, and a clock signal adjustment unit 203.
The clock signal generation unit 202 generates a clock with a period T and outputs it to the clock signal adjustment unit 203.
The clock signal adjustment unit 203 adjusts the signal level of the supplied clock and outputs the adjusted clock to the magnetic element control unit 201.

The magnetic element control unit 201 includes a detection signal amplification unit 2012, a detection signal comparison unit 2013, a feedback signal adjustment unit 2014, a feedback signal conversion unit 2015, a data signal conversion unit 2016, an excitation signal adjustment unit 2017, and an excitation signal generation unit 2018. ing.
The excitation signal generation unit 2018 generates, for example, a triangular wave that is an excitation signal shown in FIG. 19A from the clock supplied from the clock signal adjustment unit 203.
The excitation signal adjustment unit 2017 adjusts the voltage level of the excitation signal supplied from the excitation signal generation unit 2018 and supplies it to the excitation coil 301 as an excitation signal.

The exciting coil 301 generates a magnetic field corresponding to the triangular wave in the magnetic core of the magnetic element 300.
The detection coil 303 generates a pulse during positive and negative alternating time zones of the excitation signal in the magnetic core.
The feedback coil 302 generates a magnetic field that cancels out the stationary magnetic field Hex applied to the magnetic core of the magnetic element 300 based on the supplied FB signal.
The detection signal amplification unit 2012 amplifies the voltage level of the pulse supplied from the detection coil 303 and outputs the amplified voltage level to the detection signal comparison unit 2013 as a detection signal.
The detection signal comparison unit 2013 obtains the difference between the time width between the time t1 and the time t2 of the pulse (detection signal) and T / 2, and outputs this difference to the feedback signal conversion unit 2015.
The feedback signal conversion unit 2015 obtains the current value of the FB signal supplied to the feedback coil 302 from the obtained difference.

Here, the feedback signal conversion unit 2015 reads the current value corresponding to the obtained difference from the FB current value table previously written and stored in the internal storage unit, and obtains the current value of the FB signal. The FB current value table is a table showing the correspondence between the difference and the current value (digital value) that cancels the stationary magnetic field in the magnetic core.
The feedback signal adjustment unit 2014 performs D / A (Digital / Analog) conversion on the current value of the FB signal supplied from the feedback signal conversion unit 2015, and converts the generated current as the FB signal to the feedback coil 302. Output. Further, the feedback signal adjustment unit 2014 outputs the current value of the FB signal supplied from the feedback signal conversion unit 2015 to the data signal conversion unit 2016.

  The data signal conversion unit 2016 obtains the strength of the stationary magnetic field canceled in the magnetic core, that is, the strength of the stationary magnetic field Hex applied to the magnetic element 300 from the current value of the supplied FB signal. Here, the data signal conversion unit 2016 reads out the magnetic field intensity corresponding to the current value of the FB signal from the current value magnetic field table previously written and stored in the internal storage unit, and is applied to the magnetic element 300. Find the strength of the magnetic field. The current value magnetic field table is a table showing the correspondence between the current value of the FB signal and the strength of the applied stationary magnetic field Hex. A magnetic field intensity detection device (not shown) is connected to the data signal output terminal.

FIG. 21 is a diagram showing a configuration of the excitation signal adjustment unit 2017 in FIG. FIG. 21 is a diagram for explaining generation of an excitation signal by a differential signal from a triangular wave signal output from the excitation signal generation unit 2018 (not shown in FIG. 21) by the excitation signal adjustment unit 2017 of the magnetic element control device 200. (For excitation signal generation using differential signals). In FIG. 21, the excitation signal adjustment unit 2017 generates an excitation signal based on the difference between the triangular wave signal from the excitation signal generation unit 2018 and the inverted signal of this triangular wave signal, and outputs it from the output terminal.
The excitation signal adjustment unit 2017 includes an amplification circuit 20171, an inverting circuit 20172, a resistor 20151, an amplification circuit 20174, and a differential amplification circuit 20155. A resistor 500 (Rex) indicates a resistance component of the exciting coil 301. Here, the resistance 20153 has a resistance value R. The differential amplifier circuit 20175 performs voltage-current conversion by converting a voltage signal excitation signal into a current signal excitation signal using a resistor 20113.

  FIG. 22 is a diagram illustrating the configuration of the excitation signal generation unit 2018 and the excitation signal adjustment unit 2017 in FIG. FIG. 22 is a diagram illustrating generation of an excitation signal from a triangular wave signal output from the excitation signal generation unit 2018 by a single end signal by the excitation signal adjustment unit 2017 of the magnetic element control device 200 (in the case of excitation signal generation by a single end). . In FIG. 22, as in FIG. 21, the excitation signal adjustment unit 2017 generates an excitation signal based on the difference between the triangular wave signal from the excitation signal generation unit 2018 and the reference voltage Vref, and outputs it from the output terminal.

The excitation signal adjustment unit 2017 includes a resistor 20176 and a differential amplifier circuit 20077. A resistor 500 (Rex (excitation coil)) indicates a resistance component of the excitation coil 301. Here, the resistance value of the resistor 20176 is R. The differential amplifier circuit 20077 performs voltage-current conversion by converting a voltage signal excitation signal into a current signal excitation signal using a resistor 20176.
The resistor 20176 in FIG. 22 converts a triangular wave signal, which is a voltage signal, into a triangular wave current signal, and supplies it to the (−) input terminal of the differential amplifier circuit 201077.

Further, FB control by superimposing a feedback signal on the excitation signal supplied to the excitation coil using the magnetic element of FIG. 15 is also possible, and hereinafter referred to as EX coil FB control.
FIG. 23 is a graph showing the operation principle of the fluxgate type magnetic element by the EX coil FB control. FIG. 23A is a graph showing the time change of the triangular wave current signal for generating the excitation signal supplied to the excitation coil 52, with the vertical axis indicating the current and the horizontal axis indicating the time. In FIG. 23A, the triangular wave current signal supplied to the exciting coil 52 is a positive / negative alternating signal with the standard reference current 0A as a boundary. In FIG. 23B, the vertical axis indicates voltage, and the horizontal axis indicates time, and the direction of the excitation current flowing in the excitation coil 52 by the triangular wave current signal of FIG. The detection signal (first detection signal at time t1) generated in the detection coil 51 by the induced electromotive force when the polarity of the current changes and thereby the polarity of the current value of the excitation signal (excitation current) that is a current signal changes) , A second detection signal at time t2).

Here, FIG. 23A shows a stationary magnetic field in which the reference current value generated by the exciting current applied to the exciting coil 52 is applied when the stationary magnetic field (Hex) is applied to the magnetic element 50. It is shown that there is a deviation from the reference current value by the DC voltage that generates In addition, the generation timing of the first detection signal (time t1) and the second detection signal (time t2) is shifted in time corresponding to the deviation due to the stationary magnetic field (Hex) from the reference current of the excitation current. ing.
23B, the time width Tw (time width Tm, time width T0 or time width Tp) between the time t1 of the first detection signal and the time t2 of the second detection signal, and the period of the triangular wave If the difference Td from the time T / 2 that is ½ of T is 0 (in the case of the time width T0), the stationary magnetic field (Hex) is not applied to the magnetic element 50, and the difference Td is positive. If (time width Tp), a negative stationary magnetic field (Hex <0) is applied, and if the difference Td is negative (time width Tm), a positive stationary magnetic field (Hex> 0) is applied. Yes.

  FIG. 24 is a block diagram illustrating a configuration example of the magnetic element control apparatus 100 by the EX coil FB control using the magnetic element of FIG. 15 in the present embodiment. The magnetic element control device 100 detects the intensity of a stationary magnetic field applied to a fluxgate type magnetic element 50 (magnetic element in FIG. 15) composed of a detection coil 51 and an excitation coil 52 by a time-resolved magnetic balance type. At this time, the excitation signal applied to the excitation coil 52 is controlled. The magnetic element control unit 101 includes a detection signal amplification unit 1011, a detection signal comparison unit 1012, a feedback signal adjustment unit 1013, a feedback signal conversion unit 1014, a data signal conversion unit 1015, an excitation signal adjustment unit 1016, and an excitation signal generation unit 1017. ing.

The clock signal generation unit 102 includes an oscillator that generates a clock signal having a predetermined period, and outputs the generated clock signal to the clock signal adjustment unit 103.
The clock signal adjustment unit 103 performs processing such as amplifying the signal level of the supplied clock signal or changing the cycle of the clock signal, and outputs the processing result clock signal to the excitation signal generation unit 1017.

In the magnetic element control unit 101, the excitation signal generation unit 1017 generates an alternating signal, for example, a triangular wave signal as an alternating voltage signal that alternates with 0V as a reference potential, based on the clock signal supplied from the clock signal adjustment unit 103. .
The excitation signal adjustment unit 1016 amplifies the triangular wave signal generated by the excitation signal generation unit 1017 with a predetermined amplification factor, generates a triangular wave current signal, and applies it to the excitation coil 52.
The excitation signal adjustment unit 1016 generates an excitation signal, which is a triangular wave current signal applied to the excitation coil 52, by adding a feedback current If (FB signal) to the triangular wave signal.

The detection signal amplification unit 1011 amplifies the voltage across the detection coil 51 of the magnetic element 50 with a preset amplification factor.
The detection signal comparison unit 1012 compares the voltage value of the amplified detection signal supplied from the detection signal amplification unit 1011 with a predetermined threshold voltage value, and compares the first detection signal and the second detection signal (detection signal). , See FIG. 23B).
Here, as shown in FIG. 23B, the first detection signal is a negative polarity (negative voltage) pulse, and the polarity of the current applied to the exciting coil 52 changes from positive (positive current) to negative. It is generated by the induced electromotive force in a voltage region that changes to (negative current). On the other hand, the second detection signal is a positive polarity (positive voltage) pulse, and is induced in a current region where the polarity of the current applied to the exciting coil 52 changes from negative (negative current) to positive (positive current). Generated by electromotive force.

The feedback signal converter 1014 generates voltage information corresponding to the difference Td detected by the detection signal comparator 1012 (information for determining the voltage of the feedback signal described later), and outputs it as measurement data to the feedback signal adjuster 1013. .
The feedback signal adjustment unit 1013 generates a voltage corresponding to the voltage information supplied from the feedback signal conversion unit 1014, and supplies this voltage as a feedback signal to the excitation signal adjustment unit 1016 and the data signal conversion unit 1015.
The data signal conversion unit 1015 amplifies the voltage (feedback signal) supplied from the feedback signal adjustment unit 1013 with a preset amplification factor, and outputs the amplified signal as a data signal from the output terminal.

  Here, the excitation signal adjustment unit 1016 and the excitation signal generation unit 1017 of the magnetic element control device 100 have the same configuration as that of FIG. However, in FIG. 24, when the excitation signal adjustment unit 1016 in FIG. 21 generates an excitation signal as a differential signal from the triangular wave signal output from the excitation signal generation unit 1017, the feedback signal is added to the excitation signal by current. Yes. That is, in the case of FIG. 24, the excitation signal generator 1017 having the circuit configuration shown in FIG. 21 converts the feedback current of the feedback signal (the same applies when a steady current is added) to the (−) input of the differential amplifier circuit 20155. Supply to the terminal. Thereby, a feedback loop in the magnetic balance system of the magnetic element control apparatus 100 is formed.

  Further, the excitation signal adjustment unit 1016 and the excitation signal generation unit 1017 of the magnetic element control device 100 have the same configuration as that of FIG. However, in FIG. 22, when the excitation signal adjustment unit 1016 generates an excitation signal from the triangular wave signal output from the excitation signal generation unit 1017 as a single-ended signal, the feedback signal is added to the excitation signal by current. That is, in the case of the excitation signal generator 1017 having the circuit configuration shown in FIG. 22, the feedback current of the feedback signal (the same applies when a steady current is added) is supplied to the (−) input terminal of the differential amplifier circuit 20077. . Thereby, a feedback loop in the magnetic balance system of the magnetic element control apparatus 100 is formed.

  FIG. 25 is a block diagram showing a configuration example of a magnetic element control device 100A by EX coil FB control using the magnetic element of FIG. 15 in the present embodiment. The magnetic element control device 100A detects the strength of the steady magnetic field applied to the fluxgate type magnetic element 50 (the magnetic element in FIG. 15) including the detection coil 51 and the excitation coil 52 by a time-resolved magnetic balance type. At this time, the excitation signal applied to the excitation coil 52 is controlled. The magnetic element control unit 101A includes a detection signal amplification unit 1011, a detection signal comparison unit 1012, a feedback signal adjustment unit 1013, a feedback signal conversion unit 1014, a data signal conversion unit 1015, an excitation signal adjustment unit 1016, and an excitation signal generation unit 1017A. ing.

In the following, different configurations of the magnetic element control device 100A in FIG. 25 and the magnetic element control device 100 in FIG. 24 will be described.
In FIG. 24, the feedback signal from the feedback signal adjustment unit 1013 is supplied to the excitation signal adjustment unit 1016. On the other hand, in the magnetic element control device 100A shown in FIG.

  Also in FIG. 25, each of the excitation signal adjustment unit 1016 and the excitation signal generation unit 1017A has the same configuration as the excitation signal adjustment unit 1016 and the excitation signal generation unit 1017 in FIG. However, in FIG. 21, when the excitation signal adjustment unit 1016 generates an excitation signal from the triangular wave signal output from the excitation signal generation unit 1017A as a differential signal, a feedback signal is added to the excitation signal (triangular wave signal). That is, in the case of the excitation signal generation unit 1017 in FIG. 25, the feedback current of the feedback signal (the same applies when a stationary current is added) is supplied to the (−) input terminals of the amplifier circuit 20171 and the amplifier circuit 20174. Is superimposed on the excitation signal. As a result, a feedback loop in the magnetic balance system of the magnetic element control apparatus 100A is formed.

  Also in FIG. 25, each of the excitation signal adjustment unit 1016 and the excitation signal generation unit 1017A has the same configuration as the excitation signal adjustment unit 1016 and the excitation signal generation unit 1017 in FIG. However, in FIG. 22, when the excitation signal adjustment unit 1016 generates an excitation signal from the triangular wave signal output from the excitation signal generation unit 1017 in a single end, a feedback signal is added to the excitation signal (triangular wave signal). That is, in the case of the excitation signal generation unit 1017 in FIG. 25, the feedback signal is superimposed on the excitation signal supplied to the resistor 20176 connected to the (−) input terminal of the differential amplifier circuit 200777. As a result, a feedback loop in the magnetic balance system of the magnetic element control apparatus 100A is formed.

When performing magnetic detection in the magnetic field proportional type using the above-described time-resolved FG type magnetic element, the amount of magnetic field generated per current applied to the coil due to the material and structure of the magnetic core of the magnetic element 300 (hereinafter referred to as the magnetic field) , The excitation field efficiency) and the intensity of the excitation signal determine the measurable magnetic field range.
On the other hand, when performing magnetic detection in a magnetic field balance type using a time-resolved FG type magnetic element, a constant time interval (T / T) is used regardless of the stationary magnetic field Hex (external magnetic field) applied to the magnetic element 300. The magnetic field in the magnetic core is maintained in an equilibrium state so that the detection signal is output in 2). For this reason, the magnetic field can be measured within a range that is limited by the power supply voltage of the entire magnetic element 300, that is, the current value of the FB signal can be supplied.

In addition, when performing magnetic detection in the magnetic field proportional type using a time-resolved FG type magnetic element, the time interval at which the detection signal is output changes according to the magnetic field, so that the linearity of the magnetic sensitivity is It will be reflected directly in the characteristics.
On the other hand, when performing magnetic detection in a magnetic field balance type using a time-resolved FG type magnetic element, the magnetic field dependence of excitation efficiency is small as a characteristic of the magnetic element, so that the detection signal waveform and the detection signal are generated. The continuity of the time interval is easily maintained.
Therefore, when applied to a magnetic element that measures a magnetic field generated by a current of about several hundred A (ampere) as a measurement object while maintaining linearity in the entire measurement current range, compared to the conventional magnetic field proportional expression Magnetic detection in a magnetic field balance type using a time-resolved FG type magnetic element is mainly used.

JP 2007-078422 A JP 2008-292325 A JP 2007-078423 A

The above-described magnetic proportional control and magnetic field balance control are performed with each output characteristic (for example, linearity with respect to output magnetic field change, output temporal variation, current consumption of the entire device, measurable magnetic field range, magnetic sensitivity, constant environment) The output value under a magnetic field is compared below as an evaluation index.
When magnetic detection is performed by the magnetic field proportional expression using the time-resolved FG type magnetic element described above, the measurable magnetic field range is limited by the excitation efficiency and the excitation signal of the magnetic element 50 as described above.
For this reason, when a magnetic field proportional magnetic element is applied as a current sensor having a maximum measurement current of about several hundred A, in addition to the dependence of the linearity of the output of the single magnetic element on the strength of the magnetic field, the magnetic element is driven. There is a problem that the measurement range of the magnetic field that can obtain high-accuracy output linearity is limited by the limitation of the power supply voltage and the allowable maximum current value.

  Further, when the waveform of the detection signal generated by the detection coil changes depending on the strength of the stationary magnetic field Hex and the temperature of the magnetic core, the time differential value of the rise of the detection signal waveform and the output fluctuation of the detection signal There is a correlation. For this reason, the time fluctuation value of the output of the detection signal changes depending on the strength of the magnetic field, so that in the measurement of the magnetic field strength, the time fluctuation value increases, particularly as the magnetic field strength increases. The magnetic field cannot be detected.

On the other hand, when magnetic detection is performed by a magnetic field balance type using a time-resolved FG type magnetic element, in the FB (feedback) coil FB control, the FB signal is generally performed by current control.
As described above, the current value in the FB control signal and the intensity of the magnetic field generated by this current value are proportional to each other, and the temperature dependence of the magnetic sensitivity is theoretically determined by using the excitation signal as the current control. Does not occur. Therefore, there is an advantage that temperature compensation of magnetic sensitivity is unnecessary. However, even when the excitation signal is performed by current control, a method of generating an excitation triangular wave once by voltage control is generally used. For this reason, it is necessary to generate an excitation triangular wave of a current used for current control by using a voltage-current conversion circuit for the excitation triangular wave of the voltage generated by voltage control. As a result, there is a problem that the temperature change of the output value of the magnetic sensor occurs in a constant magnetic field environment depending on the temperature dependency of the offset value of the amplifier used in the voltage-current conversion circuit. Further, when an offset is superimposed on the voltage-controlled excitation signal, there is a problem that the temperature change of the output value of the magnetic sensor occurs in a constant magnetic field environment due to the temperature dependence.

  The measurement magnetic field range is represented by the product of excitation efficiency and excitation current in the magnetic element. For this reason, in order to expand (expand) the measurement magnetic field range, it can be understood from the above-described product relationship that it is effective to increase the excitation current. Here, in order to increase the excitation current, it is necessary to reduce the amplification factor of the operational amplifier used in the voltage-current conversion circuit. However, there is a problem that the operational amplifier can easily oscillate abnormally by reducing the amplification factor of the operational amplifier.

As described above, depending on the type of magnetic element control method, there are advantages and disadvantages with respect to linearity of magnetic sensitivity and current consumption. However, the characteristics relating to the temperature dependence of the offset and the temperature dependence of the magnetic sensitivity to the control method of the excitation triangular wave applied to the excitation coil are common. For this reason, the current dependency of the excitation signal reduces the temperature dependence of the magnetic sensitivity, but the temperature dependence of the output value occurs. On the other hand, when the excitation signal is voltage controlled, the temperature dependence of the output value is reduced, but the temperature dependence of the magnetic sensitivity occurs.
Therefore, it is difficult to reduce both the temperature dependency of the magnetic sensitivity and the temperature dependency of the output value at the same time, regardless of whether the excitation triangular wave is performed by voltage control or current control.

  Further, the magnetic balance type measurement magnetic field range is not restricted by the excitation efficiency and excitation current of the magnetic element. For this reason, the measurement magnetic field range is limited by the appropriate power supply voltage and the allowable maximum FB current value of the entire magnetic element. Further, by controlling the current of the feedback signal, even if the coil temperature of the feedback coil changes due to the difference in the current amount of the feedback signal and the resistance value of the coil fluctuates, the feedback signal is controlled with a constant current. For this reason, linearity with high magnetic sensitivity can be maintained even in a high magnetic field environment in which the amount of change in the feedback signal is large. Further, the time interval between the positive and negative detection signals is controlled to be constant. For this reason, the waveform of the detection signal does not change due to the external magnetic field. Therefore, there is an effect that the time fluctuation value of the output does not increase depending on the increase of the external magnetic field.

  On the other hand, when the excitation efficiency of each of the excitation coil and the feedback coil changes due to the individual deviation of the characteristics of the magnetic element, the FB convergence time in the magnetic equilibrium changes. However, it is possible to suppress the occurrence of the FB convergence residual by optimizing the design of the control circuit that controls the feedback coil. In particular, in the FB (feedback) coil FB control, when the ratio between the excitation efficiency of the excitation coil and the excitation efficiency of the feedback coil is kept constant, the ratio of the magnetic sensitivity between the excitation coil and the feedback coil does not change. The FB convergence time does not change.

Therefore, when the exciting coil and the feedback coil are formed simultaneously by a semiconductor process or the like, even if the coil resistance changes, the ratio of the coil resistance is easily maintained. Therefore, the FB convergence residual which is an index of the FB convergence and the FB There is an effect that the convergence time does not change.
On the other hand, since the magnetic field balance type requires a feedback signal of a current proportional to the magnetic field, the current consumption in the control circuit of the feedback coil increases compared to the magnetic proportional type. Further, when the feedback signal is current control, a constant current is generated as an excitation current. For this reason, it is necessary to introduce a voltage-current conversion circuit, and there is a problem that current consumption of the entire control circuit increases.

  Further, when the FB signal is current controlled, there is a problem that the reference potential of the differential signal in one control circuit is likely to fluctuate with time as the amount of feedback current increases and become unstable. In addition, when the excitation vibration is current control, the temperature of the output value of the magnetic sensor under a constant magnetic field environment is caused by the temperature dependence of the offset in the amplifier of the voltage-current converter circuit, as well as the excitation signal characteristics in the magnetic proportional type. There is a problem that changes occur.

  Further, the magnetic field measurement magnetic field range is limited by the amount of current of the feedback signal, but as described above, it can be expanded by increasing the excitation current. However, as described above, in order to increase the excitation current, it is necessary to reduce the amplification factor of the operational amplifier used in the voltage-current conversion circuit. However, there is a problem that the operational amplifier can easily oscillate abnormally by reducing the amplification factor of the operational amplifier.

As described above, characteristics of each sensor output of magnetic proportional control and magnetic balance control (output linearity, output time fluctuation value, current consumption, measured magnetic field range, magnetic sensitivity, output under constant magnetic field environment) Value) has advantages and disadvantages with respect to linearity of magnetic sensitivity and current consumption, depending on the type of control method.
However, it can be seen that the characteristics relating to the temperature dependence of the magnetic sensitivity and the output value under a constant magnetic field environment with respect to the excitation signal control method for driving the excitation coil have commonality regardless of the type of control method.

That is, when the excitation signal for driving the excitation coil is current control, the temperature dependence of the magnetic sensitivity is suppressed and reduced. Although the temperature dependence of the magnetic sensitivity is suppressed, since an excitation signal for current control is generated from an excitation signal for voltage control, an offset is superimposed on the excitation signal. As a result, there is a problem that the temperature dependence of the offset output may occur.
On the other hand, when the excitation signal is voltage controlled, the temperature dependence of the output value under a constant magnetic field environment due to the offset of the voltage-current conversion circuit can be reduced, but other circuit blocks (generate excitation signals for voltage control) In the case of the excitation signal generation unit, the detection signal amplification unit, and the magnetic balance control, the temperature dependence of the magnetic sensitivity under a constant magnetic field environment due to the offset of the feedback signal conversion unit and the feedback signal adjustment unit remains.

Therefore, even if the excitation signal control method is changed, it is difficult to simultaneously reduce both the temperature dependence of the magnetic sensitivity and the temperature dependence of the output value of the magnetic element.
In addition, when an offset adjustment unit for performing offset adjustment is added, the temperature dependence of the magnetic sensitivity of the operational amplifier used in the offset adjustment unit occurs, so the temperature dependence of the magnetic sensitivity and the temperature dependence of the offset output are simultaneously reduced. There is a problem that it is difficult.

The temperature characteristic of the output value in the zero magnetic field environment is considered to be caused by the temperature characteristic of the offset of the operational amplifier used in each circuit block in the signal processing circuit of the FG magnetic sensor in the constant magnetic field environment. .
However, on the characteristic of the circuit configuration of each operational amplifier, an offset is not a little, so the offset cannot be made completely zero. It is generally known that a chopper operation is effective as a technique for removing an offset caused by a shift in duality (matching) as transistor characteristics.

  Here, the chopper operation is an operation of adding an amount of voltage shifted from the reference potential to a signal output from the signal processing circuit in synchronization with the control clock of the signal processing circuit and canceling the offset. By this chopper operation, the offset due to duality is removed, and the temperature dependence of the offset can be reduced. However, when there is an offset generation factor other than the deviation in duality, such as a mismatch in temperature characteristics of passive elements (such as resistors and capacitors), there is no correlation between the offset and the temperature characteristics of the offset.

  Therefore, it is difficult to make the temperature change of the output value zero under a constant magnetic field environment by optimizing the design of the signal processing circuit. In particular, the input bias current of the operational amplifier is one of the causes of the offset in the output value of the operational amplifier, and increases rapidly at a specific temperature or more, and the increase rate has a large difference between individual operational amplifiers. For this reason, when the temperature change of the offset is caused by the input bias current, the individual difference of the signal processing circuit is large. Therefore, even if the output value is corrected in the data signal generation unit, there is a problem that it is difficult to maintain the temperature accuracy of the output value.

  The present invention has been made in view of such circumstances, and it is possible to reduce the temperature dependence of the offset of the output value of the operational amplifier, which cannot be removed by the chopping operation, and the magnetic element control device, An object is to provide an element control method and a magnetic detection device.

  The present invention has been made to solve the above-described problems, and the magnetic element control device of the present invention is a steady magnetic field applied to a flux gate type magnetic element in which an excitation coil and a detection coil are provided in a magnetic core. Is a magnetic element control device that controls the magnetic element when detecting the intensity of the magnetic field using a time-resolved magnetic balance method, and generates an alternating current signal from the alternating signal and an excitation signal generating unit that generates the alternating signal An excitation signal adjustment unit that generates an excitation signal to be applied to the excitation coil based on the alternating current signal, and a signal of a positive or negative voltage generated by an induced electromotive force when the current direction of the excitation signal is switched. A detection signal amplification unit that amplifies the detection signal; a detection signal comparison unit that detects a time width of the detection signal of positive and negative voltages; a feedback signal conversion unit that converts the time width into voltage information; A feedback signal adjustment unit that generates a feedback signal that applies a magnetic field that cancels a stationary magnetic field applied to the magnetic element from voltage information to the exciting coil, and data that outputs the feedback signal as a data signal indicating magnetic field strength A signal conversion unit, wherein the feedback signal is superimposed on the excitation signal in the excitation signal adjustment unit or the feedback signal adjustment unit, and the data signal conversion unit includes the excitation signal adjustment unit, the detection Controls whether the polarity of the signal input to the input terminal of the differential amplifier that generates the output in each of the signal amplification unit and the feedback signal adjustment unit is inverted or non-inverted, and a combination of a plurality of data signals Is generated and output as the data signal from this combination.

  The magnetic element control device of the present invention detects the strength of a stationary magnetic field applied to a fluxgate type magnetic element in which an excitation coil, a detection coil and a feedback coil are provided on a magnetic core by a time-resolved magnetic balance type. A magnetic element control device for controlling the magnetic element, generating an alternating signal, an alternating current signal from the alternating signal, and generating an alternating current signal from the alternating current signal in the exciting coil. An excitation signal adjustment unit that generates an excitation signal to be applied; a detection signal amplification unit that amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched; A detection signal comparison unit that detects a time width of the detection signal of a positive voltage and a negative voltage, a feedback signal conversion unit that converts the time width into voltage information, and the voltage information applied to the magnetic element In order to generate a magnetic field that cancels the normal magnetic field, a feedback signal adjustment unit that generates a feedback signal to be applied to the feedback coil, and a data signal conversion unit that outputs the feedback signal as a data signal indicating the magnetic field strength are provided. The data signal conversion unit inverts the polarity of the signal input to the input terminal of the differential amplifier that generates the output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. Or non-inverted, a combination of a plurality of data signals is generated, and a final data signal is output from the combination.

  In the magnetic element control device of the present invention, when the data signal conversion unit inverts the polarity of the output of the differential amplifier of each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit, 3 A combination of inversion and non-inversion is generated so that a logical product of inversion and non-inversion of the combination finally becomes non-inversion.

  In the magnetic element control device of the present invention, the data signal conversion unit has a sensitivity polarity of the data output in a combination of inversion and non-inversion of each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. When using within the predetermined temperature range, two combinations having the opposite temperature characteristics of the error of the data signal in a constant magnetic field environment within the temperature range are selected, and 2 for each combination. The two data signals are obtained, the two data signals are averaged, and the averaged result is used as the final data signal.

  In the magnetic element control device according to the present invention, the data signal conversion unit is configured to detect all errors in the data output in each combination of inversion and non-inversion of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. Two combinations in which the temperature characteristics of the error of the data signal under the constant magnetic field environment in the temperature range are reversed are selected, and the two data signals are obtained for each combination in the zero magnetic field. When the signal is averaged to obtain an offset value and the stationary magnetic field is measured, the averaged result of the two data signals of the combination is obtained, and the offset value is subtracted from the averaged result to obtain the final value It is a data signal.

  The magnetic element control device of the present invention applies an alternating signal to the excitation coil in a fluxgate type magnetic element in which an excitation coil and a detection coil are provided in a magnetic core, and detects the detection provided in the magnetic core. Magnetic element control for detecting a waveform of a pulsed signal having a different polarity detected corresponding to the alternating signal from the coil and controlling a magnetic element for detecting a stationary magnetic field based on a detection interval of the pulsed signal having a different polarity An excitation signal generating unit that generates the alternating signal; an excitation signal adjusting unit that generates an alternating current signal from the alternating signal and generates an excitation signal to be applied to the excitation coil based on the alternating current signal; A detection signal amplifying unit that amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched to obtain a detection signal, and a positive voltage and a negative voltage A detection signal comparison unit that detects a time width of the detection signal; and a data signal conversion unit that generates a data signal indicating a magnetic field intensity based on the time width, and the data signal conversion unit includes the excitation signal. Controls whether the polarity of the signal input to the input terminal of the differential amplifier that generates the output in each of the adjustment unit and the detection signal amplification unit is inverted or non-inverted, and a combination of a plurality of data signals It generates and outputs from the combination as the data signal.

  In the magnetic element control device of the present invention, when the data signal conversion unit inverts the polarities of the outputs of the differential amplifiers of the excitation signal adjustment unit and the detection signal amplification unit, A combination of inversion and non-inversion is generated so that a non-inversion AND finally becomes non-inversion.

  In the magnetic element control device according to the present invention, the data signal conversion unit averages and averages two data signals of the inversion and non-inversion combinations of the excitation signal adjustment unit and the detection signal amplification unit. Is the final data signal.

  In the magnetic element control device according to the present invention, the data signal conversion unit includes two pieces of the data for each combination in a zero magnetic field in each inversion and non-inversion combination of the excitation signal adjustment unit and the detection signal amplification unit. A signal is obtained, the two data signals are averaged to obtain an offset value, and when measuring a stationary magnetic field, an averaged result of the two data signals of the combination is obtained, and the offset is obtained from the averaged result. The value is subtracted to obtain the final data signal.

  A magnetic detection device according to the present invention is the magnetic element control device according to any one of the above, wherein the data signal conversion unit outputs a signal indicating a magnetic field intensity from the data signal.

  In the magnetic element control method of the present invention, when detecting the strength of a stationary magnetic field applied to a fluxgate type magnetic element in which an excitation coil and a detection coil are provided in a magnetic core, using a time-resolved magnetic balance type, A magnetic element control method for controlling the magnetic element, wherein an excitation signal generation unit generates an alternating signal, and an excitation signal adjustment unit generates an alternating current signal from the alternating signal, and the alternating signal An excitation signal adjustment process for generating an excitation signal to be applied to the excitation coil based on a current signal, and a detection signal amplifying unit for positive or negative voltage generated by an induced electromotive force when the current direction of the excitation signal is switched. A detection signal amplification process for amplifying the signal to be a detection signal, a detection signal comparison section for detecting a time width of the detection signal of positive voltage and negative voltage, and a feedback signal conversion section for the time A feedback signal generation process for converting width into voltage information, and a feedback signal adjustment unit that generates a feedback signal for applying a magnetic field for canceling a stationary magnetic field applied to the magnetic element to the excitation coil from the voltage information. A signal adjustment process, and a data signal conversion process in which the data signal conversion unit outputs the feedback signal as a data signal indicating a magnetic field strength. In the excitation signal adjustment unit or the feedback signal adjustment unit, the feedback signal Is superimposed on the excitation signal, and the data signal conversion unit is input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. The polarity of the signal to be inverted is controlled to be inverted or non-inverted, and a combination of a plurality of data signals is generated. And outputting Te.

  The magnetic element control method of the present invention detects the strength of a stationary magnetic field applied to a flux gate type magnetic element in which an excitation coil, a detection coil, and a feedback coil are provided in a magnetic core by a time-resolved magnetic balance method. A magnetic element control method for controlling the magnetic element, wherein an excitation signal generation unit generates an alternating signal, and an excitation signal adjustment unit generates an alternating current signal from the alternating signal. An excitation signal adjustment process for generating an excitation signal to be applied to the excitation coil based on the alternating current signal, and a detection signal amplifying unit that generates positive or negative generated by an induced electromotive force when the current direction of the excitation signal is switched. A detection signal amplification process that amplifies a negative voltage signal to be a detection signal, a detection signal comparison process in which a detection signal comparison unit detects a time width of the detection signal of a positive voltage and a negative voltage, and feedback signal conversion The feedback signal generation process for converting the time width into voltage information, and the feedback signal adjustment unit applies a magnetic field to the feedback coil to cancel the stationary magnetic field applied to the magnetic element from the voltage information. And a data signal conversion process in which the data signal conversion unit outputs the feedback signal as a data signal indicating a magnetic field strength, and the data signal conversion unit includes the excitation signal adjustment unit, A plurality of data signals are controlled by inverting or non-inverting the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the detection signal amplification unit and the feedback signal adjustment unit. And a final data signal is output from the combination.

  According to the magnetic element control method of the present invention, an alternating signal is applied to the excitation coil in a fluxgate type magnetic element in which an excitation coil and a detection coil are provided in the magnetic core, and the detection provided in the magnetic core is detected. Magnetic element control for detecting a waveform of a pulsed signal having a different polarity detected corresponding to the alternating signal from the coil and controlling a magnetic element for detecting a stationary magnetic field based on a detection interval of the pulsed signal having a different polarity An excitation signal generation process in which an excitation signal generation unit generates the alternating signal, and an excitation signal adjustment unit generates an alternating current signal from the alternating signal and applies the excitation coil to the excitation coil based on the alternating current signal. An excitation signal adjustment process for generating an excitation signal to be applied, and a positive or negative voltage signal generated by an induced electromotive force when the detection signal amplification unit switches the current direction of the excitation signal. A detection signal amplification process that amplifies the detection signal, a detection signal comparison unit that detects a time width of the detection signal of positive voltage and negative voltage, and a data signal conversion unit that detects the time width A data signal conversion process for generating a data signal indicating a magnetic field strength based on the input of a differential amplifier, wherein the data signal conversion unit generates an output in each of the excitation signal adjustment unit and the detection signal amplification unit Control is performed to invert or non-invert the polarity of a signal input to a terminal, a combination of a plurality of data signals is generated, and the data signal is output from the combination.

The present invention (Claim 1 and Claim 2) is the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. Is controlled to be inverted or non-inverted, a combination of a plurality of data signals is generated, and the combination is output as the data signal.
For this reason, according to the present invention, by using a combination of a plurality of data signals having different temperature dependencies of a plurality of temperature coefficients, the temperature dependency of the temperature coefficients can be relatively reduced as compared with the conventional case. The temperature characteristic of the offset of the output value of the operational amplifier, which is difficult to be removed by the chopping operation, can be reduced, and the magnetic field strength can be detected with higher accuracy than in the past.

In the present invention (Claim 6), the polarity of the signal input to the input terminal of the differential amplifier that generates the output in each of the excitation signal adjustment unit and the detection signal amplification unit is inverted or non-inverted. Is generated, a combination of a plurality of data signals is generated, and the combination is output as the data signal.
For this reason, according to the present invention, by using a combination of a plurality of data signals having different temperature dependencies of a plurality of temperature coefficients, the temperature dependency of the temperature coefficients can be relatively reduced as compared with the conventional case. The temperature characteristic of the offset of the output value of the operational amplifier, which is difficult to be removed by the chopping operation, can be reduced, and the magnetic field strength can be detected with higher accuracy than in the past.

FIG. 16 is a block diagram illustrating a configuration example of a magnetic element control device 600 by EX coil FB control using the magnetic element (magnetic element 50) of FIG. 15 in the first embodiment. It is a figure which shows the structural example of the excitation signal adjustment part 16 by 1st Embodiment in FIG. It is a figure which shows the structural example of the excitation signal adjustment part 6016 by 1st Embodiment in FIG. It is a figure which shows a response | compatibility with the data output error superimposed on the offset of the data output in the environment of a zero magnetic field, and temperature. It is a table which shows the type (type) of a temperature characteristic, and the state (polarity state) of each polarity of the detection signal amplification part 6011, the feedback signal adjustment part 6013, and the excitation signal adjustment part 6016 corresponding to each of this type. 10 is a flowchart for explaining generation of a data signal in a data signal converter 6015 when detecting a data signal in a temperature range from a temperature T0 to a characteristic temperature Ta. 10 is a flowchart for explaining generation of a data signal in a data signal converter 6015 when detecting a data signal in a temperature range from a temperature T0 to a characteristic temperature Ta. 10 is a flowchart for explaining generation of a data signal in the data signal conversion unit 6015 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0. 10 is a flowchart for explaining generation of a data signal in the data signal conversion unit 6015 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0. It is a figure which shows the structural example of the magnetic element control apparatus 650 by the 2nd Embodiment of this invention. It is a figure which shows the structural example of the magnetic element control apparatus 660 by the 3rd Embodiment of this invention. It is a figure which shows the structural example of the magnetic element control apparatus 450 by the 4th Embodiment of this invention. 15 is a flowchart for explaining generation of a data signal in a data signal conversion unit 4516 when detecting a data signal in a temperature range from a temperature T0 to a characteristic temperature Ta. 15 is a flowchart for explaining generation of a data signal in a data signal conversion unit 4516 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0. It is a figure which shows the structural example of the magnetic element (magnetic field proportional measurement) of a time-resolved FG system. It is a wave form diagram explaining the principle of the magnetic detection in a magnetic field proportional type using a time-resolved FG type magnetic element. It is a schematic block diagram which shows the structural example of the magnetic detection apparatus using the magnetic element control apparatus in a magnetic field proportional control using a time-resolved FG type magnetic element. It is a figure which shows the structural example of the magnetic element (magnetic field balance type | mold measurement) of a time-resolved FG system. It is a wave form diagram explaining the principle of the magnetic detection in a magnetic field balance type | mold measurement using a time-resolved FG type magnetic element. It is a block diagram which shows the structural example of the magnetic detection apparatus using the magnetic element control apparatus in FB (feedback) coil FB control. It is a figure which shows the structure of the excitation signal production | generation part 2018 and the excitation signal adjustment part 2017 in FIG. It is a figure which shows the structure of the excitation signal production | generation part 2018 and the excitation signal adjustment part 2017 in FIG. It is a graph which shows the principle of operation by EX coil FB control of a fluxgate type magnetic element. It is a block diagram which shows the structural example of the magnetic element control apparatus 100 by EX coil FB control using the magnetic element of FIG. 15 in this embodiment. It is a block diagram which shows the structural example of 100 A of magnetic element control apparatuses by EX coil FB control using the magnetic element of FIG. 15 in this embodiment.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The present embodiment is a magnetic element control apparatus that performs magnetic balance type magnetic detection processing using an FG magnetic element. FIG. 1 is a block diagram showing a configuration example of a magnetic element control device 600 by EX coil FB control that applies an FB signal to an excitation signal generation unit using the magnetic element (magnetic element 50) of FIG. 15 in the first embodiment. It is. In the following, the same components as those in FIGS. 24 and 25 are denoted by the same reference numerals.
The magnetic element control device 600 to be inspected according to the present embodiment uses a time-resolved magnetic balance to determine the strength of a stationary magnetic field applied to an FG (flux gate) type magnetic element 50 including a detection coil 51 and an excitation coil 52. When detecting by the equation, the excitation signal applied to the excitation coil 52 is controlled.

  The magnetic element control device 600 includes a clock signal generation unit 102, a clock signal adjustment unit 103, and a magnetic element control unit 601. The magnetic element control unit 601 includes a detection signal amplification unit 6011, a detection signal comparison unit 1012, a feedback signal adjustment unit 6013, a feedback signal conversion unit 6014, a data signal conversion unit 6015, an excitation signal adjustment unit 6016, and an excitation signal generation unit 1017A. ing.

The clock signal generation unit 102 includes an oscillator that generates a clock signal having a predetermined period, and outputs the generated clock signal to the clock signal adjustment unit 103.
The clock signal adjustment unit 103 performs processing such as amplifying the signal level of the supplied clock signal or changing the cycle of the clock signal, and outputs the processing result clock signal to the excitation signal generation unit 1017.

  In the magnetic element control unit 601, the excitation signal generation unit 1017A generates an alternating signal, for example, a triangular wave signal as an alternating voltage signal alternating with 0V as a reference potential, based on the clock signal supplied from the clock signal adjustment unit 103. . Here, as will be described later, the excitation signal generation unit 1017A is supplied with a feedback signal from the feedback signal adjustment unit 6013, superimposes the feedback signal on the generated triangular wave signal, and converts the triangular wave signal on which the feedback signal is superimposed to the next stage. Is output to the excitation signal adjusting unit 6016.

  2 corresponds to the case of the circuit configuration of FIG. 2 in which an excitation signal adjusting unit 6016 described later uses an excitation signal and an inverted excitation signal. In the excitation signal generation unit 1017A, a positive amplifier circuit and a negative amplifier are connected using an operational amplifier or the like. An amplifier circuit is formed. In addition, in this excitation signal generation unit 1017A, by using an analog switch synchronized with the clock signal supplied from the clock signal adjustment unit 103, a rectangular wave whose polarity is inverted is generated, and a positive polarity and a negative polarity are generated. Each of the signals may be amplified.

The excitation signal adjustment unit 6016 amplifies the triangular wave signal generated by the excitation signal generation unit 1017A at a predetermined amplification factor, generates a triangular wave current signal, and applies it to the excitation coil 52.
The excitation signal adjustment unit 6016 applies an excitation signal, which is a triangular wave current signal on which a feedback signal is superimposed, to the excitation coil 52.

Next, FIG. 2 is a diagram illustrating a configuration example of the excitation signal adjusting unit 16 according to the first embodiment in FIG. A configuration using a differential amplifier similar to that of the excitation signal adjustment unit 1016 in FIG. 21 is provided with switching elements SW1_1, switching elements SW1_2, switching elements SW2_1, and SW2_1 for changing the polarity state (described later). Except for the addition of the switching element, the same operation as the excitation signal adjustment unit 1016 in FIG. 21 is performed.
In FIG. 2, an excitation signal adjustment unit 6016 generates an excitation signal based on the difference between the triangular wave signal from the excitation signal generation unit 1017A and the inverted signal of the triangular wave signal, and outputs the excitation signal from the output terminal.

The excitation signal adjustment unit 6016 includes an amplification circuit 20171, an inversion circuit 20172, a resistor 20151, an amplification circuit 20174, and a differential amplification circuit 20155. The resistor 500 corresponds to the exciting coil 52. Here, the resistance 20153 has a resistance value R. The differential amplifier circuit 20175 performs voltage-current conversion by converting a voltage signal excitation signal into a current signal excitation signal using a resistor 20113.
In the case of the excitation signal adjustment unit 6017 having the circuit configuration shown in FIG. 2, the feedback current of the feedback signal (the same applies when a steady current is added) is superimposed on the triangular wave signal from the excitation signal generation unit 1017A as described above. ing.

The switching element SW1_1 is interposed between the output terminal of the amplifier circuit 20171 and the non-inverting input terminal (+) of the inverting circuit 20152.
Further, the switching element SW1_2 is interposed between the output terminal of the amplifier circuit 20171 and the non-inverting input terminal (+) of the differential amplifier circuit 20155.
The switching element SW2_1 is interposed between the output terminal of the amplifier circuit 20174 and the non-inverting input terminal (+) of the differential amplifier circuit 20155.
The switching element SW2_2 is interposed between the output terminal of the amplifier circuit 20174 and the non-inverting input terminal (+) of the inverting circuit 20172.

Thus, when the switching element SW1_1 is on and the switching element SW1_2 is off, the output of the amplifier circuit 20171 is supplied to the non-inverting input terminal (+) of the inverting circuit 20172. On the other hand, when the switching element SW1_1 is off and the switching element SW1_2 is on, the output of the amplifier circuit 20171 is supplied to the non-inverting input terminal (+) of the differential amplifier circuit 20155.
When the switching element SW2_1 is on and the switching element SW2_2 is off, the output of the amplifier circuit 20174 is supplied to the non-inverting input terminal (+) of the differential amplifier circuit 20155. On the other hand, when the switching element SW2_1 is off and the switching element SW2_2 is on, the output of the amplifier circuit 20174 is supplied to the non-inverting input terminal (+) of the inverting circuit 20172.

That is, each of the switching elements SW1_1, SW1_2, SW2_1, and SW2_2 has an output of the amplifier circuit 17171 and an output of the amplification stage and an output of 20144, a non-inverting input terminal (+) of the inverting circuit 20152, and a non-inverting terminal of the differential amplifier circuit 20155. Switches which of the inverting input terminals (+) is connected.
Here, the output of the amplifier circuit 20171 is connected to the non-inverting input terminal (+) of the inverting circuit 20172, and the output of the amplifier circuit 20174 is connected to the non-inverting input terminal (+) of the differential amplifier circuit 20155. Non-inverted. On the other hand, the output of the amplifier circuit 20171 is connected to the non-inverting input terminal (+) of the differential amplifier circuit 20155, and the state where the output of the amplifier circuit 20174 is connected to the non-inverting input terminal (+) of the inverting circuit 20172 is inverted. And

FIG. 3 is a diagram illustrating a configuration example of the excitation signal adjustment unit 6016 according to the first embodiment in FIG. A configuration using a differential amplifier similar to that of the excitation signal adjustment unit 1016 in FIG. 22 is provided with a switching element SW1 and a switching element SW2. Except for the addition of the switching element, the same operation as the excitation signal adjustment unit 1016 in FIG. 22 is performed.
In FIG. 3, the excitation signal adjustment unit 6016 generates an excitation signal based on the difference between the triangular wave signal from the excitation signal generation unit 2017A and the inverted signal of the triangular wave signal, and outputs the excitation signal from the output terminal. In FIG. 3, the excitation signal adjustment unit 6016 generates an excitation signal based on the difference between the triangular wave signal from the excitation signal generation unit 2017A and the reference voltage Vref, and outputs the excitation signal to the excitation coil 52 from the output terminal.

The excitation signal adjustment unit 6016 includes a resistor 20176, a differential amplifier circuit 20077, and an inverting circuit 20178. The resistor 500 corresponds to the exciting coil 52. Here, the resistance 20176 has a resistance value R, one end is connected to the output of the excitation signal generation unit 1017A, and the other end outputs a triangular wave signal converted into a current. The differential amplifier circuit 20107 performs voltage-current conversion by converting a voltage signal excitation signal into a current signal (lex) excitation signal by a resistor 20176. The inverting circuit 20178 inverts the triangular wave signal output from the resistor 20176.
In the case of the excitation signal adjustment unit 6017 having the circuit configuration shown in FIG. 3, as described above, the feedback current of the feedback signal (the same applies when a steady current is added) is superimposed on the triangular wave signal from the excitation signal generation unit 1017A. ing.

The switching element SW1 is inserted between the other end of the resistor 20176 and the inverting input terminal (−) of the differential amplifier 201077.
Further, the switching element SW2 is interposed between the output of the inverting circuit 20178 and the inverting input terminal (−) of the differential amplifier circuit 20077.
Accordingly, when the switching element SW1 is on and the switching element SW2 is off, the other end of the resistor 20176 is connected to the inverting input terminal (−) of the differential amplifier circuit 20077. On the other hand, when the switching element SW1 is off and the switching element SW2 is on, the inverting input terminal (−) of the differential amplifier circuit 20077 is supplied to the output terminal of the inverting circuit 20178.

That is, each of the switching elements SW1 and SW2 switches which of the other end of the resistor 20176 and the output terminal of the inverting circuit 20178 is connected to the inverting input terminal (−) of the differential amplifier circuit 20077.
Here, a state in which the inverting input terminal (−) of the differential amplifier circuit 20077 is connected to the other end of the resistor 20176 is non-inverted. On the other hand, a state where the inverting input terminal (−) of the differential amplifier circuit 20077 is connected to the output terminal of the inverting circuit 20178 is inverted. Here, the inversion indicates that the polarity of the output from the excitation signal adjustment unit 6016 is inverted with respect to the case where the output is not inverted.

Returning to FIG. 1, the detection signal amplification unit 6011 amplifies the voltage across the detection coil 51 of the magnetic element 50 with a preset amplification factor. Here, similarly to the excitation signal adjustment unit 6016 described above, the detection signal amplification unit 6011 is provided with a switching element inside, and has a configuration that can invert the polarity of the output.
The detection signal comparison unit 1012 compares the voltage value of the amplified detection signal supplied from the detection signal amplification unit 6011 with a predetermined threshold voltage value, and compares the first detection signal and the second detection signal (detection signal). , See FIG. 23B).
Here, as shown in FIG. 23B, the first detection signal is a negative polarity (negative voltage) pulse, and the polarity of the current applied to the exciting coil 52 changes from positive (positive current) to negative. It is generated by the induced electromotive force in a voltage region that changes to (negative current). On the other hand, the second detection signal is a positive polarity (positive voltage) pulse, and is induced in a current region where the polarity of the current applied to the exciting coil 52 changes from negative (negative current) to positive (positive current). Generated by electromotive force.

The feedback signal converter 1014 generates voltage information corresponding to the difference Td detected by the detection signal comparator 1012 (information for determining the voltage of the feedback signal described later), and outputs it as measurement data to the feedback signal adjuster 6013. .
The feedback signal adjustment unit 6013 generates a voltage corresponding to the voltage information supplied from the feedback signal conversion unit 1014, and supplies this voltage as a feedback signal to the excitation signal generation unit 1017A and the data signal conversion unit 6015. Here, similarly to the excitation signal adjustment unit 6016 described above, the feedback signal adjustment unit 6013 is provided with a switching element inside, and has a configuration capable of inverting the polarity of the output.

  The data signal conversion unit 6015 amplifies the voltage (feedback signal) supplied from the feedback signal adjustment unit 6013 with a preset amplification factor, and outputs the amplified signal as a data signal from the output terminal. For example, the data signal conversion unit 6015 reads the magnetic field intensity corresponding to the voltage value of the voltage information from the voltage value magnetic field table previously written and stored in the internal storage unit, and is a stationary magnetic field applied to the magnetic element 50. Find the strength of. The voltage value magnetic field table is a table in which the voltage value of the voltage information is associated with the strength of the stationary magnetic field Hex corresponding to the voltage value.

  In the present embodiment, as the configuration for generating the voltage of the feedback signal, the magnetic element control can be performed by any of a configuration performed by digital processing using a digital value and a configuration performed by analog processing using an analog value. Apparatus 600 can be configured. Hereinafter, a configuration for generating the voltage of the feedback signal by digital processing and a configuration for generating the feedback voltage by analog processing will be described in order.

Configuration for generating feedback signal voltage by digital processing The detection signal comparison unit 1012 measures the time width from the first detection signal to the second detection signal, and the time width Tw (Tp, Tm, etc.) and the period of the triangular wave A half time of T, that is, a difference Td (= Tw− (T / 2)) from T / 2 is obtained and output to the feedback signal converter 1014.
When the difference Td that is time information is supplied from the detection signal comparison unit 1012, the feedback signal conversion unit 1014 generates voltage information that generates a voltage of the feedback signal as the FB signal from the difference Td.
Here, in the feedback signal conversion unit 1014, a time voltage information table indicating the correspondence between the difference Td and the voltage information of the digital value corresponding to the difference Td is written and stored in advance in the internal storage unit.

  The feedback signal conversion unit 1014 reads voltage information corresponding to the supplied difference Td from the temporal voltage information table stored in the internal storage unit, and outputs the voltage information to the feedback signal adjustment unit 6013. For example, the voltage information is digital value data indicating the voltage value of the feedback signal. Moreover, the polarity of the difference Td is attached to the voltage information, that is, the voltage information has a positive polarity when the difference Td is positive, and has a negative polarity when the difference Td is negative. Accordingly, when a stationary magnetic field Hex having a positive polarity is applied to the magnetic element 50, the excitation signal adjustment unit 6016 has a negative polarity feedback current If with respect to the drive current I generated from the triangular wave voltage signal. Is superimposed as a feedback signal. On the other hand, when a stationary magnetic field Hex having a negative polarity is applied, a feedback current If of a positive polarity is superimposed as a feedback signal on the drive current I generated from the triangular wave voltage signal.

The feedback signal adjustment unit 6013 generates a feedback signal having a voltage value indicated by the voltage information based on the voltage information supplied from the feedback signal conversion unit 1014, and outputs the generated feedback signal to the excitation signal adjustment unit 6016.
Here, since the voltage information is a digital value, the feedback signal adjustment unit 6013 includes a D / A converter, for example, and inputs the supplied voltage information, which is a digital value, to the D / A converter. A voltage is obtained and output to the excitation signal adjustment unit 6016 as a feedback signal.
The excitation signal adjustment unit 6016 superimposes the feedback current If generated from the feedback signal supplied from the feedback signal adjustment unit 6013 on the drive current I generated internally from the triangular wave voltage signal, and forms an excitation coil 52 as a triangular wave current signal. Apply to.

When the feedback current If is superimposed on the triangular wave current signal (excitation current), the time interval between the first detection signal and the second detection signal detected by the detection signal comparison unit 1012 is in the vicinity of T / 2.
For this reason, when the feedback current If is already superimposed on the triangular wave current signal, the detection signal comparator 1012 outputs the feedback current If necessary for setting the time information to be T / 2 and the feedback current currently applied. The current value of the difference from If is shown. Therefore, when the excitation signal is applied, the detection signal comparison unit 1012 outputs the difference Td to the feedback signal conversion unit 1014 as time information indicating the above-described difference current value.

Further, when the difference Td, which is time information indicating the difference current value, is supplied, the feedback signal conversion unit 1014 generates voltage information for generating a current value corresponding to the difference Td as described above. Read from the time voltage information table stored in the internal storage unit, and output to the feedback signal adjustment unit 6013.
The feedback signal adjustment unit 6013 has a storage unit therein, and voltage information is accumulated and stored in the storage unit, and is output to the excitation signal adjustment unit 6016 using the accumulated voltage information. A voltage of the feedback signal is generated and output to the excitation signal adjustment unit 6016.
Here, the feedback signal adjustment unit 6013 determines whether or not the voltage information corresponding to the difference Td is included in a preset set voltage range.

When the voltage information is not included in the set voltage range, the feedback signal adjustment unit 1013 does not change the magnetic field even when applied to cancel the stationary magnetic field applied to the magnetic element 50. That is, it is determined that the voltage has no influence on cancellation.
That is, the feedback signal adjustment unit 6013 determines an error in control accuracy when changing the magnetic field strength, and determines that the time width of the first detection signal and the second detection signal is approximately T / 2. At this time, the feedback signal adjustment unit 6013 discards the voltage information within the error range without adding it to the time information immediately before the internal storage unit.

The data signal conversion unit 6015 amplifies the voltage information supplied from the feedback signal adjustment unit 6013 with a preset amplification degree and outputs the amplified voltage information to the outside.
The amplification degree in the data signal conversion unit 6015 is set to a value that outputs only the voltage value range of the feedback signal in a linearly measurable range in advance as a data signal. In other words, this amplification degree is a voltage obtained by amplifying only the range in which the magnetic field that cancels the stationary magnetic field and the feedback signal of the voltage value that generates this magnetic field maintain linearity, and the voltage outside the range is saturated to a constant voltage. It is what. That is, the data signal conversion unit 6015 sets a predetermined gain at which the voltage value of the feedback signal and the voltage value of the feedback signal outside the voltage range of the feedback signal in which the magnetic field strength generated by the voltage value is linear are saturated. Thus, the feedback signal is amplified and output.

Therefore, this data signal may be a magnetic field voltage for obtaining the strength of the magnetic field for canceling the stationary magnetic field, that is, a voltage signal indicating the strength of the stationary magnetic field. A voltage value of the magnetic field voltage indicated by the data signal may be converted into a magnetic field strength by an external magnetic field strength detection device (not shown), and the converted magnetic field strength may be output.
Here, in the magnetic field strength detection device, a magnetic field strength table indicating the correspondence between the voltage value of the magnetic field voltage and the strength of the magnetic field corresponding to the voltage value of the magnetic field voltage is written and stored in advance in the internal storage unit. ing.

  In this case, the magnetic detection device reads the magnetic field strength corresponding to the voltage value of the magnetic field voltage indicated by the data signal supplied from the magnetic element control device 600 from the magnetic field strength table, and sets it as a numerical value of the strength of the stationary magnetic field (Hex). For example, it is displayed on a display unit provided in itself. Thus, in the present invention, a magnetic detection device may be configured by the magnetic element control device 600 and the magnetic field intensity detection device (not shown) described above. The same applies to other second, third, and fourth embodiments to be described later.

  When the feedback signal conversion unit 1014 uses a TDC circuit that converts the time interval of the rectangular wave indicating the duty ratio of the characteristic obtained by the detection signal comparison unit 10212 into a digital value, the feedback signal adjustment unit 6013 includes a feedback signal. It is desirable to set signal convergence conditions. The convergence condition includes an arbitrary digital value and its deviation, an allowable maximum value of the feedback signal, an upper limit value of the number of feedbacks until convergence, and the like.

A configuration for generating the voltage of the feedback signal by analog processing The detection signal comparison unit 1012 detects the rising portion of the first detection signal and the rising portion of the second detection signal output from the detection signal amplification unit, and the feedback signal conversion unit 1014 Output for.
The feedback signal converter 1014 generates a pulse having a duty ratio as voltage information based on the period (the interval between the time t1 and the time t2, that is, the time width) in which the first detection signal and the second detection signal are output. The pulse is output as voltage information to the feedback signal adjustment unit 1013.

That is, the feedback signal conversion unit 1014 obtains a duty ratio indicating the voltage value of the feedback signal from the time width as voltage information, and outputs a rectangular wave having the duty ratio indicating the voltage value of the feedback signal to the feedback signal adjustment unit 6013. Output.
When the information is indicated by a rectangular wave signal, the feedback signal adjustment unit 6013 generates a DC voltage corresponding to the duty ratio by a PWM (Pulse Width Modulation) circuit or the like and outputs it as a feedback signal.

For example, when the time width from the first detection signal to the second detection signal is longer than the time width from the second detection signal to the first detection signal, the stationary magnetic field needs to be negative. Therefore, the feedback signal adjustment unit 6013 generates a DC voltage feedback signal that generates a positive magnetic field that cancels the stationary magnetic field.
On the other hand, when the time width from the second detection signal to the first detection signal is longer than the time width from the first detection signal to the second detection signal, since the stationary magnetic field is positive, the feedback signal adjustment unit 6013 A DC voltage feedback signal that generates a negative magnetic field that cancels the stationary magnetic field is generated.

That is, when a pulse as voltage information is supplied, the feedback signal adjustment unit 6013 generates a feedback signal having a voltage value corresponding to the duty ratio of the pulse, and the generated feedback signal is sent to the excitation signal adjustment unit 6016. Output. When a PWM circuit is used for the feedback signal converter 6014, the data signal converter 6015 is provided with a limiter circuit that defines a desired signal range of the analog signal to be output (a range in which the linearity of the output value with respect to the magnetic field strength is ensured). It is desirable to provide a configuration.
Here, the excitation signal adjustment unit 6016 has the configuration of FIG. 2 or FIG. 3 as described above.

  In the case of FIG. 2, the excitation signal adjustment unit 6016 includes the amplification circuit 20171, the inverting circuit 20172, the resistor 20151, the amplification circuit 20174, the differential amplification circuit 20155, and each of the switching elements SW1_1, 1_2, 2_1, and 2_2. It has. When the switching element is switched, that is, when the excitation signal adjustment unit 6016 is in a non-inverted polarity state, the switching element SW1_1 is on, the switching element SW1_2 is off, the switching element SW2_1 is on, and the switching element SW2_2 is off. Yes, the output of the amplifier circuit 20171 is connected to the non-inverting input (+) of the inverting circuit 20172, and the output of the amplifier circuit 20174 is connected to the non-inverting input (+) of the differential amplifier circuit 20155.

  On the other hand, when the excitation signal adjustment unit 6016 is in the reverse polarity state, the switching element SW1_1 is off, the switching element SW1_2 is on, the switching element SW2_1 is off, and the switching element SW2_2 is on. Is connected to the non-inverting input (+) of the differential amplifier circuit 20155, and the output of the amplifier circuit 20174 is connected to the non-inverting input (+) of the inverter circuit 20172. As a result, when the excitation signal adjustment unit 6016 is in the inverted polarity state and the excitation signal adjustment unit 6016 is in the non-inverted polarity state, the inverting input (−) and the non-inverting input (+ The polarity of the excitation signal supplied to) is inverted.

  The resistor 500 corresponds to the exciting coil 52. The excitation signal adjustment unit 6016 generates an excitation signal based on a difference between the triangular wave signal (with a feedback signal superimposed) from the excitation signal generation unit 2017A and an inverted signal of the triangular wave signal, and outputs the excitation signal from the output terminal to the excitation coil 52. , Output non-inverted or inverted.

  On the other hand, in the case of FIG. 3, the excitation signal adjustment unit 6016 includes a resistor 20176, a differential amplifier circuit 20077, a switching element SW1, and a switching element SW2. When the switching element is switched, that is, when the excitation signal adjustment unit 6016 is in the non-inverted polarity state, the switching element SW1 is in the on state, the switching element SW2 is in the off state, and the triangular wave signal supplied via the resistor 20176 Are directly connected to the inverting input (−) of the differential amplifier circuit 20077.

  On the other hand, when the excitation signal adjustment unit 6016 is in the inverted polarity state, the switching element SW1 is in the off state, the switching element SW2 is in the on state, and the output of the inverting circuit 20178 is the inverting input (−) of the differential amplifier circuit 20077. It is connected to the. As a result, when the excitation signal adjustment unit 6016 is in the inverted polarity state and the excitation signal adjustment unit 6016 is in the non-inversion polarity state, the triangular wave signal supplied to the inverting input (−) of the differential amplifier circuit 20077. The polarity of is reversed.

  The resistor 500 corresponds to the exciting coil 52. The excitation signal adjustment unit 6016 generates an excitation signal based on the difference between the triangular wave signal (with the feedback signal superimposed) from the excitation signal generation unit 1017A and the reference voltage Vref, and generates a resistor 500 (excitation coil from the output terminal). 52).

As described above, the feedback current If superimposed on the triangular wave signal supplied to the excitation signal adjustment unit 6016 is proportional to the external magnetic field (stationary magnetic field Hex). Then, by superimposing it on the drive current I (triangular wave current signal) as the feedback current If corresponding to the feedback signal and applying it to the exciting coil 52, a magnetic field is generated by this feedback current If, and the magnetic core in the magnetic element 50 is generated. Is adjusted so that the time width of the first detection signal and the second detection signal is constant at T / 2.
As a result, the time interval between the first detection signal and the second detection signal can be kept constant without depending on the external stationary magnetic field.

As in the case of digital processing, the excitation signal generation unit 1017A superimposes the feedback signal supplied from the feedback signal adjustment unit 6013 on the triangular wave voltage signal generated inside the control circuit. Then, the excitation signal adjustment unit 6016 applies a triangular wave current signal generated from the triangular wave voltage signal on which the feedback signal is superimposed to the excitation coil 52 as an excitation signal.
Since the operation of the data signal conversion unit 6015 is the same as that of digital processing except that the analog value is amplified, the description thereof is omitted. In the present embodiment, the chopper operation of the excitation signal adjustment unit 6016 is validated. On the other hand, the feedback signal adjustment unit 6013 may make the feedback convergence unstable due to the chopper operation, and invalidates the chopper operation. Similarly, the detection signal amplifying unit 6011 disables the chopper operation because the detection in the detection signal comparison unit 1012 becomes unstable due to the chopper operation.

  FIG. 4 is a diagram showing a correspondence between the data output error superimposed on the offset of the data output in the environment of the zero magnetic field and the temperature. In FIG. 4, the vertical axis represents the numerical value of the data output error, and the horizontal axis represents the temperature. The data output error indicates a difference between the reference numerical value at the temperature T0 and the offset at the zero magnetic field at each temperature with the offset at the temperature T0 as a reference. For example, the magnetic element control device 600 is used in the temperature range from the temperature T0 to the temperature Ta. However, FIG. 4 shows the temperature characteristics of only one individual among the plurality of magnetic element control devices 600 detected. The temperature dependency tendency of the data output error in FIG. 4 changes for each magnetic element control device 600.

  FIG. 5 shows the types of temperature characteristics (types) and the inversion or non-inversion states (polarities) of the polarities of the detection signal amplification unit 6011, feedback signal adjustment unit 6013, and excitation signal adjustment unit 6016 corresponding to each of these types. State). The types correspond to the four combinations (1), (2), (3) and (4) shown in the table. That is, there are four combinations when the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 are in the non-inverted and inverted states. Here, all four circuits are in a non-inverted state (1), or any one circuit is in a non-inverted state, and the remaining two circuits are in an inverted state. There are (2), (3) and (4). That is, the combination of the three polarities of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 is non-inverted. Here, there are six combinations of inversion and non-inversion, but combinations other than the four described above are not used in this embodiment because feedback control does not converge.

  In FIG. 5, in the non-inversion and inversion states of the polarities indicated by the respective polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016, the type (1) is the excitation signal adjustment unit 6016. Is a non-inverted state, the detection signal amplifying unit 6011 is in a non-inverted state, and the feedback signal adjusting unit 6013 is in a non-inverted state. In type (2), the excitation signal adjustment unit 6016 is in an inverted state, the detection signal amplification unit 6011 is in a non-inversion state, and the feedback signal adjustment unit 6013 is in an inversion state. Type (3) is an excitation signal adjustment unit 6016 in an inverted state, a detection signal amplification unit 6011 in an inverted state, and a feedback signal adjustment unit 6013 in a non-inversion state. In type (4), the excitation signal adjustment unit 6016 is in a non-inverted state, the detection signal amplification unit 6011 is in an inverted state, and the feedback signal adjustment unit 6013 is in an inverted state. Switching between the non-inverted state and the inverted state of each of the detection signal amplifying unit 6011, the feedback signal adjusting unit 6013, and the excitation signal adjusting unit 6016 is performed by switching on and off the switching element in each unit as described above. .

  As shown in FIG. 4, in the data curve of type (1) in FIG. 4, the polarity state of the excitation signal adjustment unit 6016 is non-inverted, and the polarity state of the detection signal amplification unit 6011 is non-inverted. The correspondence relationship between the data output error and the temperature when the polarity state of the feedback signal adjustment unit 6013 is non-inverted is shown. In the data curve of type (2) in FIG. 4, the polarity state of the excitation signal adjustment unit 6016 is inverted, the polarity state of the detection signal amplification unit 6011 is non-inversion, and the polarity state of the feedback signal adjustment unit 6013 is A correspondence relationship between data output error and temperature in the case of inversion is shown. In the type (3) data curve of FIG. 4, the polarity state of the excitation signal adjustment unit 6016 is inverted, the polarity state of the detection signal amplification unit 6011 is inverted, and the polarity state of the feedback signal adjustment unit 6013 is non-inversion. The correspondence relationship between data output error and temperature in a certain case is shown. In the data curve of type (4) in FIG. 4, the polarity state of the excitation signal adjustment unit 6016 is non-inverted, the polarity state of the detection signal amplification unit 6011 is inverted, and the polarity state of the feedback signal adjustment unit 6013 is inverted. The correspondence relationship between data output error and temperature in a certain case is shown.

  In addition, in each of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016, the polarity of the sensitivity in each circuit is changed by switching the switching element, in addition to the polarity state in which the output is inverted and non-inverted. Change. Here, the polarity of sensitivity (hereinafter referred to as sensitivity polarity) is measured by the detection signal comparison unit 1012 measuring the time interval of the detection signal between the first detection signal and the second detection signal, and the offset amount of the excitation signal. Depends on. Therefore, when the polarity state of the excitation signal output by the excitation signal adjustment unit 6016 is reversed, the sensitivity polarity of the increase / decrease of the feedback signal with respect to the magnetic field is reversed. However, when the polarity state of the excitation signal output by the excitation signal adjustment unit 6016 is non-inverted and only the polarity state of the output of the detection signal amplification unit 6011 is inverted, the sensitivity polarity of increase / decrease of the feedback signal with respect to the magnetic field is not inverted. . On the other hand, the sensitivity polarity of the increase / decrease of the feedback signal in the feedback signal adjustment unit 6013 is inverted by inverting the polarity state of the feedback signal in the feedback signal adjustment unit 6013.

The sensitivity polarities of type (2), type (3), and type (4) will be described below with reference to the polarity state and sensitivity polarity in the case of type (1).
-Type (2) Since the polarity state of the excitation signal adjustment unit 6016 is reversed, the polarity state of the detection signal output from the magnetic element 50 is reversed. The detection signal amplification unit 6011 has an output in which the sensitivity polarity is inverted because the polarity state is non-inverted. Further, the polarity of the feedback signal adjustment unit 6012 is inverted. For this reason, since the sensitivity polarity of the feedback signal is inverted, the sensitivity polarity of the feedback signal becomes the same as that of the type (1), and as a result, the feedback converges. As described above, the polarity state of the excitation signal is inverted, the sensitivity polarity of the detection signal is inverted, and the sensitivity polarity of the feedback signal generated from the inverted detection signal is inverted. Is finally the same as type (1).

• Type (3) Since the polarity state of the excitation signal adjustment unit 6016 is reversed, the polarity state of the detection signal output from the magnetic element 50 is reversed. Since the polarity state of the detection signal amplifier 6011 is reversed, the detection signal amplification unit 6011 has an output that does not reverse the sensitivity polarity, and has the same sensitivity polarity as that of the type (1). Further, the polarity of the feedback signal adjustment unit 6012 is not inverted. For this reason, the sensitivity polarity of the feedback signal is the same as that of the type (1), and as a result, the feedback converges. In addition, since the polarity state of the excitation signal is inverted to reverse the sensitivity polarity of the detection signal, and the polarity of the feedback signal generated from the inverted detection signal is non-inverted, the sensitivity polarity is set to type (1). Inversely.

In the case of type (4) Since the polarity state of the excitation signal adjustment unit 6016 is not inverted, the polarity state of the detection signal output from the magnetic element 50 is the same as that of the type (1). Since the detection signal amplification unit 6011 has an inverted polarity state, the detection signal amplification unit 6011 has an output with the sensitivity polarity inverted, and has a sensitivity polarity inverted with respect to the type (1). Further, the polarity of the feedback signal adjustment unit 6012 is inverted. For this reason, the sensitivity polarity of the feedback signal is the same as that of the type (1), and as a result, the feedback converges. Further, since the polarity state of the excitation signal is non-inverted, the sensitivity polarity of the detection signal is not inverted, and the polarity of the feedback signal generated from the inverted detection signal is inverted, the sensitivity polarity is type (3). Inverts for type (1) as well.
As described above, in the individual in this embodiment, the polarity state of each of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 is changed from type (1) to type (4). In this case, type (1) and type (2) have the same sensitivity polarity, and type (3) and type (4) have the same sensitivity polarity.

  In the individual magnetic element control device 600 of FIG. 4, when the magnetic element 50 exists in the temperature environment below the specific temperature Ta from the table showing the polarity state of FIG. 5, the polarity state of the feedback signal adjustment unit 6013, It can be seen that there is a correlation between the polarity of the temperature coefficient of the data output error. In the individual magnetic element control device 600 of FIG. 4, when the magnetic element 50 exists in a temperature environment equal to or higher than the specific temperature Ta, there is a correlation between the polarity state of the detection signal amplification unit 6011 and the polarity of the temperature coefficient of the data output error. I know that there is. In this embodiment, the chopper operation is disabled for the feedback signal adjustment unit 6013. For this reason, it is considered that the temperature characteristic of the output of the detection signal amplification unit 6011 has an influence on the data output error below the temperature T0.

  On the other hand, in order to remove the influence on the data output error of the detection signal amplification unit 6011, the detection signal amplification unit 6011 may be provided with a DC (Direct Current, DC) cut filter. However, due to the offset of the output of the operational amplifier in the detection signal amplification unit 6011, the offset is superimposed on the output of the detection signal amplification unit 6011. In particular, when a mismatch in transistor characteristics of the transistors constituting the transistor pair increases in the transistor pair constituting the operational amplifier in the detection signal amplification unit 6011 due to a temperature rise, the offset superimposed on the output of the operational amplifier increases. In an actual operational amplifier circuit, the above-described offset component cannot be made completely zero. Therefore, it is considered that the detection signal amplification unit 6011 constituted by the operational amplifier has the temperature dependence of the data output error as shown in FIG.

  From the results described above, in this embodiment, the data signal conversion unit 6015 has a function of controlling the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016. As can be seen from the graph of FIG. 4, the types (1) and (2) have the same sensitivity polarity, and the change characteristics with respect to the temperature of the data output error in the temperature range from the temperature T0 to the specific temperature Ta are opposite. . For this reason, the data signal conversion unit 6015 changes the polarity state of each of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016, the switching element provided in each circuit, and the clock signal generation unit 102. The polarity state of each of the type (1) and the type (2) is set for each cycle by performing on / off control for each cycle in synchronization with the clock signal generated by.

For example, in the case of the excitation signal adjustment unit 6016 in FIG. 2, the data signal conversion unit 6015 sets the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 to the type (1) polarity state. The switching element SW1_1 is turned on, the switching element SW1_2 is turned off, the switching element 2_1 is turned on, and the switching element SW2_2 is turned off.
In the case of the excitation signal adjustment unit 6016 in FIG. 2, the data signal conversion unit 6015 sets the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 to the type (2) polarity state. The switching element SW1_1 is turned off, the switching element SW1_2 is turned on, the switching element 2_1 is turned off, and the switching element SW2_2 is turned on.

On the other hand, in the case of the excitation signal adjustment unit 6016 in FIG. 3, the data signal conversion unit 6015 sets each of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 to the type (1) polarity state. The switching element SW1 is turned on and the switching element SW2 is turned off.
In the case of the excitation signal adjustment unit 6016 in FIG. 3, the data signal conversion unit 6015 sets the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 to the type (2) polarity state. The switching element SW1 is turned off and the switching element SW2 is turned on.

The data signal conversion unit 6015 receives the feedback signal of the voltage Vb1 in the type (1) polarity state and the feedback signal of the voltage Vb2 in the type (2) polarity state, which are input from the feedback signal adjustment unit 6013 every cycle. Enter. Next, the data signal converter 6015 adds the voltage Vb1 and the voltage Vb2, and divides the addition result by 2 and averages the result. Then, the data signal conversion unit 6015 obtains and outputs a data signal from the averaged numerical value. The method for obtaining the data signal is the same as the operation already described.
In other words, in the present embodiment, for example, the sensitivity polarity is the same and the temperature characteristics of the data output error are opposite in the temperature range from the temperature T0 set as the operable temperature range to the characteristic temperature Ta. The average value of the type data output is obtained and output as the final data output.

  Further, for each individual magnetic element control device 600, the sensitivity polarity of each type is different, and the combination of types for calculating the average value is different. Therefore, when the data curve for each type shown in FIG. 4 is obtained for each individual magnetic element control device 600, any two types have the same sensitivity polarity and the temperature range from the temperature T0 to the characteristic temperature Ta. The temperature characteristic of the data output error is reverse. For this reason, the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 have the same sensitivity polarity and the reverse temperature characteristics of the data output error in the temperature range from the temperature T0 to the characteristic temperature Ta. For the two types of polar states, the above-described averaging process is set for the data signal converter 6015.

  FIG. 6 is a flowchart for explaining generation of a data signal in the data signal converter 6015 when detecting a data signal in the temperature range from the temperature T0 to the characteristic temperature Ta. In FIG. 6, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 are sequentially controlled to each of the type (1) and the type (2), and the type (1) and It is a flowchart which shows the process which acquires each voltage value Vb1 and voltage value Vb2, and averages and obtains a data signal in each of type (2).

Step S11:
The data signal conversion unit 6015 synchronizes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal, for changing the polarity state provided in the respective units. The switching element is controlled to be turned on and off, and is set to the type (1) polarity state.
As a result, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 correspond to the type (1), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (1) is output from the feedback signal adjustment unit 6013 as the voltage value Vb1.

Step S12:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb1) output from the detection signal amplification unit 6011, and temporarily writes and stores the feedback signal (voltage value Vb1) in an internal storage unit.

Step S13:
The data signal conversion unit 6015 changes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal in the next cycle of the cycle in step S11. On / off control of the switching element for changing the polarity state provided in the section is set to the polarity state of type (2). At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
As a result, the polar states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 correspond to the type (2), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (2) is output from the feedback signal adjustment unit 6013 as the voltage value Vb2.

Step S14:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time. Here, the feedback signal to be stored is a signal that has passed for a fixed time after the switching of the switching element for changing the polarity state. The constant time here means a time during which it can be determined that the feedback signal outputs a constant value at a steady magnetic field and a steady temperature.
Then, when the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S15 on the assumption that the certain time has elapsed since the on / off control of the switching element is performed and the feedback signal is stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. To step S14.

Step S15:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb2) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S16:
The data signal conversion unit 6015 reads the voltage value Vb1 and the voltage value Vb2 from the storage unit provided therein, adds the voltage value Vb1 and the voltage value Vb2, and divides the addition result by 2 and averages the result. .

Step S17:
The data signal conversion unit 6015 refers to the voltage value magnetic field table stored in the storage unit provided therein, obtains the strength of the magnetic field corresponding to the averaged voltage value ((Vb1 + Vb2) / 2), and determines the data signal. Output as.

  FIG. 7 is a flowchart for explaining generation of a data signal in the data signal converter 6015 when detecting a data signal in the temperature range from the temperature T0 to the characteristic temperature Ta. In FIG. 7, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 are sequentially controlled to the type (3) and the type (4), respectively, and the type (3) In each of type (4), it is a flowchart which shows the process which acquires each voltage value Vb3 and voltage value Vb4, and averages and acquires a data signal.

  As shown in FIG. 4, the polarity polarity of the type (3) is the same as that of the type (4), and the two types of polarity states have the opposite temperature characteristics of the data output error in the temperature range from the temperature T0 to the specific temperature Ta. In addition to the combination of type (1) and type (2), there is a combination of type (3) and type (4) (determined from FIG. 4). For this reason, in the flowchart of FIG. 7, instead of the combination of type (1) and type (2), the data signal conversion unit 6015 obtains the type (3) by the combination of type (3) and type (4). The feedback signal voltage value Vb3 and the feedback signal voltage value Vb4 obtained by the type (4) are averaged to obtain a data signal.

Step S21:
The data signal conversion unit 6015 synchronizes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal for changing the polarity state provided in the respective units. The switching element is controlled to be turned on and off, and is set to the type (3) polarity state.
Thereby, each polarity state of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 corresponds to the type (3), and the magnetic element control device 600 performs the magnetic field detection processing already described. The detection signal amplification unit 6011 outputs a feedback signal corresponding to the type (3) polarity state as the voltage value Vb3.

Step S22:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb3) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein.

Step S23:
The data signal conversion unit 6015 changes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal in the next cycle of the cycle in step S11. ON / OFF control of the switching element for changing the polarity state provided in the section is set to the type (4) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
Thereby, each polarity state of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 corresponds to the type (4), and the magnetic element control device 600 performs the magnetic field detection processing already described. The detection signal amplifying unit 6011 outputs a feedback signal corresponding to the type (4) polarity state as the voltage value Vb4.

Step S24:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
If the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S25 assuming that the certain time has elapsed since the on / off control of the switching element has been performed and the feedback signal has stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S24.

Step S25:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb4) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S26:
The data signal conversion unit 6015 reads the voltage value Vb1 and the voltage value Vb2 from the storage unit provided therein, adds the voltage value Vb3 and the voltage value Vb4, divides the addition result by 2, and averages the result. .

Step S27:
The data signal conversion unit 6015 refers to the voltage value magnetic field table stored in the storage unit provided therein, obtains the strength of the magnetic field corresponding to the averaged voltage value ((Vb3 + Vb4) / 2), and outputs the data signal Output as.

  FIG. 8 is a flowchart for explaining generation of a data signal in the data signal converter 6015 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0. In FIG. 8, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 are sequentially controlled to the type (1) and the type (4), respectively, and the type (1) and In each of type (4), it is a flowchart which shows the process which acquires each voltage value Vb1 and voltage value Vb4, and averages and acquires a data signal.

From FIG. 4, the sensitivity polarities of type (1) and type (4) are the same at characteristic temperature Ta or higher, and the two types of polarities have the opposite temperature characteristics of data output error in the temperature range above specific temperature Ta. The state includes a combination of type (1) and type (4).
FIG. 8A is a flowchart for obtaining an offset value in a reference magnetic field (for example, zero magnetic field) before the shipment of the magnetic element control device 600. The data signal conversion unit 6015 obtains the offset value obtained by the inspection before shipment for each predetermined temperature in the entire temperature range, and writes and stores it in the internal storage unit.

  FIG. 8B is a flowchart for explaining generation of a data signal in the data signal conversion unit 6015 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0 after the magnetic element control device 600 is shipped. is there. That is, in FIG. 8B, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 are sequentially controlled to each of the type (1) and the type (4), It is a flowchart which shows the process which acquires each voltage value Vb1 and voltage value Vb4 in each of type (1) and type (4), and averages and acquires a data signal.

This will be described with reference to the flowchart of FIG.
Step S31a:
An arbitrary uniform magnetic field is generated in a specific spatial region with respect to the orthogonal three-axis direction by a coil that can apply a uniform magnetic field in the orthogonal three-axis direction (hereinafter referred to as “three-axis Helmholtz coil”). An environment in which the magnetic element can be used is prepared, and the magnetic element control device 600 to which the magnetic element 50 is added is installed in the environment. A zero magnetic field is applied to the magnetic element 50.

Step S32a:
The data signal conversion unit 6015 synchronizes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal, for changing the polarity state provided in the respective units. The switching element is controlled to be turned on and off, and is set to the type (1) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
As a result, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 correspond to the type (1), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (1) is output from the feedback signal adjustment unit 6013 as the voltage value Vb1.

Step S33a:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
If the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S34a on the assumption that the certain time has elapsed since the on / off control of the switching element has been performed and the feedback signal has stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S33a.

Step S34a:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb1) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S35a:
The data signal conversion unit 6015 changes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal in the next cycle of the cycle in step S11. ON / OFF control of the switching element for changing the polarity state provided in the section is set to the type (4) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
Thereby, each polarity state of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 corresponds to the type (4), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (4) is output from the feedback signal adjustment unit 6013 as the voltage value Vb4.

Step S36a:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
When the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S37a on the assumption that the certain time has elapsed since the on / off control of the switching element has been performed and the feedback signal has stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S36a.

Step S37a:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb4) output from the detection signal amplification unit 6011, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S38a:
The data signal conversion unit 6015 reads the voltage value Vb1 and the voltage value Vb4 from the storage unit provided inside, adds the voltage value Vb1 and the voltage value Vb4, divides the addition result by 2, and averages the result. The offset value is calculated.

  The above-described processing for obtaining the offset value from step S31a to step S36a is performed for each predetermined temperature in the entire temperature range, the offset value for each predetermined temperature in the entire temperature range is obtained, and this offset value is obtained as a data signal conversion unit. The data is written and stored in a storage unit provided inside 6015. The processing for writing the obtained off-installation processing in the storage unit inside the data signal conversion unit 6015 may be performed by the data signal conversion unit 6015 itself, or may be performed by a computer that temporarily receives the data signal.

Next, the flowchart of FIG. 8B will be described. In the case of the operation shown in the flowchart of FIG. 8B, the operation after shipment is shown, and the magnetic element 50 is placed under a normal steady magnetic field.
Step S31:
The data signal conversion unit 6015 synchronizes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal, for changing the polarity state provided in the respective units. The switching element is controlled to be turned on and off, and is set to the type (1) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
As a result, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 correspond to the type (1), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (1) is output from the feedback signal adjustment unit 6013 as the voltage value Vb1.

Step S32:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
Then, if the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S33, assuming that the certain time has elapsed since the on / off control of the switching element is performed and the feedback signal is stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S32.

Step S33:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb1) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S34:
The data signal conversion unit 6015 changes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal in the next cycle of the cycle in step S11. ON / OFF control of the switching element for changing the polarity state provided in the section is set to the type (4) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
Thereby, each polarity state of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 corresponds to the type (4), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (4) is output from the feedback signal adjustment unit 6013 as the voltage value Vb4.

Step S35:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
Then, if the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S36 on the assumption that the certain time has elapsed since the on / off control of the switching element is performed and the feedback signal is stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S35.

Step S36:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb4) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S37:
The data signal conversion unit 6015 reads out the voltage value Vb1 and the voltage value Vb2 from the storage unit provided therein, adds the voltage value Vb1 and the voltage value Vb2, and divides the addition result by 2, and averages the result. Measured value data is calculated.

Step S38:
The data signal converter 6015 reads temperature data from a temperature sensor (not shown) provided in the magnetic element control device 600.
Then, the data signal conversion unit 6015 refers to the offset value table stored in the internal storage unit, and reads the offset value corresponding to the temperature data. Here, when there is no offset value corresponding to the measured temperature, the data signal conversion unit 6015 performs complementation such as averaging adjacent offset values above and below the measured temperature.
The data signal converter 6015 subtracts the offset value from the voltage value ((Vb1 + Vb4) / 2) of the measurement value data to obtain corrected measurement value data.
Then, the data signal conversion unit 6015 refers to the voltage value magnetic field table stored in the internal storage unit, obtains the strength of the magnetic field corresponding to the corrected measurement value data, and outputs it as a data signal.

  FIG. 9 is a flowchart for explaining generation of a data signal in the data signal converter 6015 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0. In FIG. 9, the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 are sequentially controlled to the type (2) and the type (3), respectively, and the type (2) In each of type (3), it is a flowchart which shows the process which acquires each voltage value Vb1 and voltage value Vb4, and averages and acquires a data signal.

From FIG. 4, the sensitivity polarities of type (2) and type (3) are the same at characteristic temperature Ta or higher, and the two types of polarities have opposite temperature characteristics of data output error in the temperature range above specific temperature Ta. The state includes a combination of type (2) and type (3). In the flowchart of FIG. 9, the data signal conversion unit 6015 obtains the type (2) by using the combination of the type (2) and the type (3) instead of the combination of the type (1) and the type (4). The feedback signal voltage value Vb2 and the feedback signal voltage value Vb3 obtained by the type (3) are averaged to obtain a data signal.
FIG. 9A is a flowchart for obtaining an offset value in a reference magnetic field (for example, zero magnetic field) before the shipment of the magnetic element control device 600. The data signal conversion unit 6015 obtains the offset value obtained by the inspection before shipment for each predetermined temperature in the entire temperature range, and writes and stores it in the internal storage unit.

This will be described with reference to the flowchart of FIG.
Step S41a:
Prepare an environment that can generate an arbitrary uniform magnetic field in a specific spatial region with respect to the orthogonal three-axis direction, such as by a three-axis Helmholtz coil that can apply a uniform magnetic field in the orthogonal three-axis direction, A magnetic element control device 600 to which the magnetic element 50 is added is installed in the environment. A zero magnetic field is applied to the magnetic element 50.

Step S42a:
The data signal conversion unit 6015 synchronizes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal. The switching element is on / off controlled and set to the type (2) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
As a result, the polar states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 correspond to the type (2), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (2) is output from the feedback signal adjustment unit 6013 as the voltage value Vb2.

Step S43a:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
Then, when the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S44a on the assumption that the certain time has elapsed since the on / off control of the switching element has been performed and the feedback signal has stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S43a.

Step S44a:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb2) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S45a:
The data signal conversion unit 6015 changes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal in the next cycle of the cycle in step S11. On / off control of the switching element for changing the polarity state provided in the section is set to the type (3) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
Thereby, each polarity state of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 corresponds to the type (3), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (3) is output from the feedback signal adjustment unit 6013 as the voltage value Vb3.

Step S46a:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
Then, when the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S47a on the assumption that the certain time has elapsed since the on / off control of the switching element is performed and the feedback signal is stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S46a.

Step S47a:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb3) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S48a:
The data signal conversion unit 6015 reads the voltage value Vb2 and the voltage value Vb3 from the storage unit provided inside, adds the voltage value Vb2 and the voltage value Vb3, divides the addition result by 2, and averages the result. The offset value is calculated.

  The above-described processing for obtaining the offset value from step S41a to step S46a is performed for each predetermined temperature in the entire temperature range, the offset value for each predetermined temperature in the entire temperature range is obtained, and this offset value is used as the data signal conversion unit. The data is written and stored in a storage unit provided inside 6015. The processing for writing the obtained off-installation processing in the storage unit inside the data signal conversion unit 6015 may be performed by the data signal conversion unit 6015 itself, or may be performed by a computer that temporarily receives the data signal.

Next, the flowchart of FIG. 9B will be described. In the case of the operation shown in the flowchart of FIG. 9B, the operation after shipment is shown, and the magnetic element 50 is placed under a normal steady magnetic field.
Step S41:
The data signal conversion unit 6015 synchronizes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal. The switching element is on / off controlled and set to the type (2) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
As a result, the polar states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 correspond to the type (2), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (2) is output from the feedback signal adjustment unit 6013 as the voltage value Vb1.

Step S42:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
Then, if the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S43, assuming that the certain time has elapsed since the on / off control of the switching element has been performed and the feedback signal has stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S42.

Step S43:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb2) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S44:
The data signal conversion unit 6015 changes the polarity states of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 in synchronization with the clock signal in the next cycle of the cycle in step S11. On / off control of the switching element for changing the polarity state provided in the section is set to the type (3) polarity state. At this time, the data signal conversion unit 6015 starts a timer provided therein, and starts counting the elapsed time after the on / off control of the switching element.
Thereby, each polarity state of the detection signal amplification unit 6011, the feedback signal adjustment unit 6013, and the excitation signal adjustment unit 6016 corresponds to the type (3), and the magnetic element control device 600 performs the magnetic field detection processing already described. The feedback signal corresponding to the polarity state of type (3) is output from the feedback signal adjustment unit 6013 as the voltage value Vb4.

Step S45:
The data signal conversion unit 6015 determines whether or not a predetermined time has elapsed after the on / off control of the switching element. That is, the data signal conversion unit 6015 determines whether or not the elapsed time counted by the timer has exceeded a preset fixed time.
Then, when the elapsed time exceeds a certain time, the data signal conversion unit 6015 advances the processing to step S46 on the assumption that the certain time has elapsed since the on / off control of the switching element is performed and the feedback signal is stabilized at a certain value. . On the other hand, when the elapsed time is equal to or shorter than the predetermined time, the data signal conversion unit 6015 determines that the predetermined time has not elapsed since the on / off control of the switching element and the feedback signal is not stable at a constant value. Advances to step S45.

Step S46:
The data signal conversion unit 6015 receives the feedback signal (voltage value Vb3) output from the feedback signal adjustment unit 6013, and temporarily writes and stores it in a storage unit provided therein. At this time, the data signal conversion unit 6015 resets the timer provided therein to “0”.

Step S47:
The data signal conversion unit 6015 reads the voltage value Vb2 and the voltage value Vb3 from the storage unit provided inside, adds the voltage value Vb2 and the voltage value Vb3, divides the addition result by 2, and averages the result. Measured value data is calculated.

Step S48:
The data signal converter 6015 reads temperature data from a temperature sensor provided in the magnetic element control device 600.
Then, the data signal conversion unit 6015 refers to the offset value table stored in the internal storage unit, and reads the offset value corresponding to the temperature data. Here, when there is no offset value corresponding to the measured temperature, the data signal conversion unit 6015 performs complementation such as averaging adjacent offset values above and below the measured temperature.
The data signal converter 6015 subtracts the offset value from the voltage value ((Vb2 + Vb3) / 2) of the measurement value data to obtain corrected measurement value data.
Then, the data signal conversion unit 6015 refers to the voltage value magnetic field table stored in the internal storage unit, obtains the strength of the magnetic field corresponding to the corrected measurement value data, and outputs it as a data signal.

  As described above, in the present embodiment, by performing the operations of the flowcharts of FIGS. 6 and 7, the sensitivity polarity is the same, and the temperature of the offset output error in the temperature range from the temperature T0 to the characteristic temperature Ta. A feedback signal is obtained in each of two types of polar states having opposite characteristics, and the two types of feedback signals are added and averaged to obtain measurement data, and the magnetic field strength is obtained from the measurement data. For this reason, according to this embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operations of the flowcharts of FIGS. 6 and 7, that is, removed by the chopping operation. This makes it possible to reduce the temperature dependence of the offset of the output value of the operational amplifier, which cannot be performed, and to detect the strength of the magnetic field with higher accuracy than before.

  Further, in the present embodiment, by performing the operations of the flowcharts of FIGS. 8 and 9, the temperature characteristics of the data output error are the same in the sensitivity polarity and in the entire temperature range including the characteristic temperature Ta from the temperature T0. In each of the two types of polarity states that are opposite, a zero magnetic field is obtained for each temperature in the entire temperature range, and the two types of feedback signals are averaged to obtain an offset value. After obtaining the feedback signal, adding the two types of feedback signals, and subtracting the offset corresponding to the temperature at the time of measurement as measurement data, the magnetic field strength is obtained from the measurement data. Therefore, according to the present embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operations of the flowcharts of FIGS. 8 and 9, that is, by the chopping operation. The temperature dependence of the offset of the output value of the operational amplifier, which cannot be removed, can be reduced, and the magnetic field strength can be detected with higher accuracy than before.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. The present embodiment is a magnetic element control apparatus that performs magnetic balance type magnetic detection processing using an FG magnetic element. FIG. 10 is a diagram illustrating a configuration example of a magnetic element control device 650 according to the second embodiment of the present invention. That is, the magnetic element control device 650 in FIG. 10 shows a configuration example of the magnetic element control device 650 by EX coil FB control that applies the FB signal to the excitation signal adjustment unit using the magnetic element (magnetic element 50) in FIG. It is a block diagram. In the following, the same components as those in FIG. 1, FIG. 11 and FIG.
The magnetic element control device 650 to be inspected according to the present embodiment detects the strength of the steady magnetic field applied to the fluxgate magnetic element 50 including the detection coil 51 and the excitation coil 52 by a time-resolved magnetic balance method. In this case, the excitation signal applied to the excitation coil 52 is controlled.

  The magnetic element control device 650 includes a clock signal generation unit 102, a clock signal adjustment unit 103, and a magnetic element control unit 651. The magnetic element control unit 651 includes a detection signal amplification unit 6011, a detection signal comparison unit 1012, a feedback signal adjustment unit 6013, a feedback signal conversion unit 6014, a data signal conversion unit 6015, an excitation signal adjustment unit 6016A, and an excitation signal generation unit 1017. ing.

The clock signal generation unit 102 includes an oscillator that generates a clock signal having a predetermined period, and outputs the generated clock signal to the clock signal adjustment unit 103.
The clock signal adjustment unit 103 performs processing such as amplifying the signal level of the supplied clock signal or changing the cycle of the clock signal, and outputs the processing result clock signal to the excitation signal generation unit 1017.

  In the magnetic element control unit 651, the excitation signal generation unit 1017 generates an alternating signal, for example, a triangular wave signal as an alternating voltage signal that alternates with 0 V as a reference potential, based on the clock signal supplied from the clock signal adjustment unit 103. .

  In the case where the excitation signal adjustment unit 6016A has a configuration corresponding to the circuit configuration of FIG. 2 using an excitation signal (triangular wave signal) and an inverted excitation signal, the excitation signal generation unit 1017 performs positive amplification using an operational amplifier or the like. A circuit and a negative amplifier circuit are formed. In addition, the excitation signal generation unit 1017 generates a rectangular wave whose polarity is inverted by using an analog switch synchronized with the clock signal supplied from the clock signal adjustment unit 103, and has a positive polarity and a negative polarity. Each of the signals may be amplified.

The excitation signal adjustment unit 6016A amplifies the triangular wave signal generated by the excitation signal generation unit 1017A with a predetermined amplification factor, generates a triangular wave current signal, and applies it to the excitation coil 52.
Here, as will be described later, the excitation signal adjustment unit 6016A is supplied with the feedback signal from the feedback signal adjustment unit 6013, and superimposes it on the triangular wave current signal that generates the feedback signal.
The excitation signal adjustment unit 1016A applies an excitation signal, which is a triangular wave current signal on which a feedback signal is superimposed, to the excitation coil 52.

  Next, the excitation signal adjustment unit 6016A in FIG. 10 has the configuration shown in FIG. 2 in the same manner as the excitation signal adjustment unit 6016 in FIG. The difference between the excitation signal adjustment unit 6016A and the excitation signal adjustment unit 6016 is that the feedback signal is not superimposed on the supplied triangular wave signal, and the inversion of the differential amplifier circuit 2015 is similar to the excitation signal adjustment unit 1016 of FIG. A feedback signal is supplied to the input terminal (−). The operations of the switching element SW1_1, the switching element SW1_2, the switching elements SW2_1, and SW2_1 are the same as those of the excitation signal adjustment unit 6016 in FIG.

Further, the excitation signal adjustment unit 6016A in FIG. 10 may have the configuration shown in FIG. 3 similarly to the excitation signal adjustment unit 6016 in FIG. The difference between the excitation signal adjustment unit 6016A and the excitation signal adjustment unit 6016 is that the feedback signal is not superimposed on the supplied triangular wave signal, and as with the excitation signal adjustment unit 1016 in FIG. A feedback signal is supplied to the input terminal (−). The operation of each of the switching element SW1 and the switching element SW2 is the same as that of the excitation signal adjustment unit 6016 in FIG.
Also in the second embodiment, similarly to the first embodiment, the operations according to the flowcharts of FIGS. 6, 7, 8, and 9 are performed.

  Accordingly, in the present embodiment, by performing the operations of the flowcharts of FIGS. 6 and 7, the sensitivity polarity is the same as in the first embodiment, and the temperature range from the temperature T0 to the characteristic temperature Ta. The feedback signal is obtained in each of the two types of polar states in which the temperature characteristics of the data output error are opposite to each other, and the two types of feedback signals are added and averaged to obtain measurement data. Seeking strength. For this reason, according to this embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operations of the flowcharts of FIGS. 6 and 7, that is, removed by the chopping operation. This makes it possible to improve the temperature characteristics of the offset of the output value of the operational amplifier, which is difficult to do, and to detect the strength of the magnetic field with higher accuracy than in the past.

  Further, in the present embodiment, by performing the operations of the flowcharts of FIGS. 8 and 9, the sensitivity polarity is the same as in the first embodiment, and the entire temperature range including the characteristic temperature Ta from the temperature T0. In each of the two types of polar states where the temperature characteristics of the data output error are reversed, the zero magnetic field is obtained for each temperature in the entire temperature range, and the two types of feedback signals are averaged to obtain the offset value. The two types of feedback signals are obtained even under a magnetic field, and after adding the two types of feedback signals, the result of subtracting the offset corresponding to the temperature at the time of measurement is used as measurement data, and the strength of the magnetic field is obtained from the measurement data. Seeking. Therefore, according to the present embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operations of the flowcharts of FIGS. 8 and 9, that is, by the chopping operation. The temperature characteristic of the offset of the output value of the operational amplifier, which is difficult to remove, can be improved, and the magnetic field strength can be detected with higher accuracy than in the past.

<Third Embodiment>
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. The present embodiment is a magnetic element control device that performs magnetic balance type magnetic detection processing using a fluxgate type magnetic element. FIG. 11 is a diagram illustrating a configuration example of a magnetic element control device 660 according to the third embodiment of the present invention. That is, the magnetic element control device 660 according to the present embodiment is a magnetic element control device based on FB coil FB control using the magnetic element (magnetic element 300) of FIG. In the following, the same components as those in FIGS. 1 and 10 are denoted by the same reference numerals.
The magnetic element control device 660 to be inspected according to the present embodiment uses the time-resolved magnetic field intensity of the stationary magnetic field applied to the fluxgate magnetic element 300 including the excitation coil 301, the feedback coil 302, and the detection coil 303. When detecting by the balanced type, the excitation signal applied to the excitation coil 301 is controlled.

Next, the magnetic element control device 660 in FIG. 11 uses magnetic element control in FB (feedback) coil FB control. In FIG. 11, as described above, the magnetic element 300 is an EX coil in which the magnetic element of FIG.
The magnetic element control device 660 includes a magnetic element control unit 661, a clock signal generation unit 102, and a clock signal adjustment unit 103.

The magnetic element control unit 661 includes a detection signal amplification unit 6011, a detection signal comparison unit 1012, a feedback signal adjustment unit 6013, a feedback signal conversion unit 1014, a data signal conversion unit 6015, an excitation signal adjustment unit 6016, and an excitation signal generation unit 1017. ing.
The excitation signal generation unit 1017 generates, for example, a triangular wave that is an excitation signal shown in FIG. 19A from the clock supplied from the clock signal adjustment unit 203.
The excitation signal adjustment unit 6016 adjusts the voltage level of the excitation signal supplied from the excitation signal generation unit 1017 and supplies it to the excitation coil 301 as an excitation signal.

The exciting coil 301 generates a magnetic field corresponding to the triangular wave in the magnetic core of the magnetic element 300.
The detection coil 303 generates a pulse during positive and negative alternating time zones of the excitation signal in the magnetic core.
The feedback coil 302 generates a magnetic field that cancels the steady magnetic field Hex applied to the magnetic core of the magnetic element 300 by the supplied feedback signal.
The detection signal amplification unit 6011 amplifies the voltage level of the pulse supplied from the detection coil 303 and outputs the amplified voltage level to the detection signal comparison unit 2013 as a detection signal.
The detection signal comparison unit 1012 obtains the difference between the time width of the pulse (detection signal) between time t1 and time t2 and T / 2, and outputs this difference to the feedback signal conversion unit 1014.
The feedback signal conversion unit 1014 obtains the current value of the feedback signal supplied to the feedback coil 302 from the obtained difference.

Here, the feedback signal conversion unit 1014 reads the current value corresponding to the obtained difference from the FB current value table previously written and stored in the internal storage unit, and obtains the current value of the feedback signal. The FB current value table is a table showing the correspondence between the difference and the current value (digital value) that cancels the stationary magnetic field in the magnetic core.
The feedback signal adjustment unit 6013 performs D / A (Digital / Analog) conversion on the current value of the feedback signal supplied from the feedback signal conversion unit 1014, and converts the generated current as the feedback signal to the feedback coil 302. Output. Further, the feedback signal adjustment unit 6013 outputs the current value of the feedback signal supplied from the feedback signal conversion unit 1014 to the data signal conversion unit 6015.

  The data signal converter 6015 obtains the strength of the stationary magnetic field canceled in the magnetic core of the magnetic element 300, that is, the strength of the stationary magnetic field Hex applied to the magnetic element 300 from the current value of the supplied feedback signal. Here, as already described, the data signal conversion unit 6015 reads out the magnetic field strength corresponding to the current value of the feedback signal from the current value magnetic field table previously written and stored in the internal storage unit, and outputs the magnetic field. The strength of the magnetic field applied to the element 300 is obtained. The generation of the feedback current is the same as that of the magnetic element control device 200 of FIG. 20 already described. The detection signal comparison unit 1012 corresponds to the detection signal comparison unit 2013, and the feedback signal conversion unit 1014 corresponds to the feedback signal conversion unit 2015.

Next, the excitation signal adjustment unit 6016 in FIG. 11 has the configuration shown in FIG. 2 in the same manner as the excitation signal adjustment unit 6016 in FIG. The operations of the switching element SW1_1, the switching element SW1_2, the switching elements SW2_1, and SW2_1 are the same as those of the excitation signal adjustment unit 6016 in FIG.
Further, the excitation signal adjustment unit 6016 in FIG. 11 may have the configuration shown in FIG. 3 similarly to the excitation signal adjustment unit 6016 in FIG. The operation of each of the switching element SW1 and the switching element SW2 is the same as that of the excitation signal adjustment unit 6016 in FIG.
Also in the second embodiment, similarly to the first embodiment, the operations according to the flowcharts of FIGS. 6, 7, 8, and 9 are performed.

  Accordingly, in the present embodiment, by performing the operations of the flowcharts of FIGS. 6 and 7, the sensitivity polarity is the same as in the first embodiment, and the temperature range from the temperature T0 to the characteristic temperature Ta. The feedback signal is obtained in each of the two types of polar states in which the temperature characteristics of the data output error are opposite to each other, and the two types of feedback signals are added and averaged to obtain measurement data. Seeking strength. For this reason, according to this embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operations of the flowcharts of FIGS. 6 and 7, that is, removed by the chopping operation. This makes it possible to improve the temperature characteristics of the offset of the output value of the operational amplifier, which is difficult to do, and to detect the strength of the magnetic field with higher accuracy than in the past.

  Further, in the present embodiment, by performing the operations of the flowcharts of FIGS. 8 and 9, the sensitivity polarity is the same as in the first embodiment, and the entire temperature range including the characteristic temperature Ta from the temperature T0. In each of the two types of polar states where the temperature characteristics of the data output error are reversed, the zero magnetic field is obtained for each temperature in the entire temperature range, and the two types of feedback signals are averaged to obtain the offset value. The two types of feedback signals are obtained even under a magnetic field, and after adding the two types of feedback signals, the result of subtracting the offset corresponding to the temperature at the time of measurement is used as measurement data, and the strength of the magnetic field is obtained from the measurement data. Seeking. Therefore, according to the present embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operations of the flowcharts of FIGS. 8 and 9, that is, by the chopping operation. The temperature dependence of the offset of the output value of the operational amplifier, which cannot be removed, can be reduced, and the magnetic field strength can be detected with higher accuracy than before.

<Fourth Embodiment>
Next, a fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 12 is a diagram showing a configuration example of a magnetic element control device 450 according to the fourth embodiment of the present invention. The magnetic element control device 450 according to the fourth embodiment is a magnetic element control device using a magnetic element control device in magnetic field proportional control using a time-resolved FG type magnetic element. In FIG. 12, a magnetic element 50 is the magnetic element shown in FIG. 12, and includes a detection coil 51 and an excitation coil 52.
The magnetic element control device 450 includes a magnetic element control unit 401, a clock signal generation unit 402, and a clock signal adjustment unit 403.
The clock signal generation unit 402 generates a clock with a period T and outputs it to the clock signal adjustment unit 403.
The clock signal adjustment unit 403 adjusts the signal level of the supplied clock and outputs the adjusted clock to the magnetic element control unit 401.

The magnetic element control unit 451 includes a detection signal amplification unit 4512, a detection signal comparison unit 4013, an output signal generation unit 4015, a data signal conversion unit 4516, an excitation signal adjustment unit 4517, and an excitation signal generation unit 4018.
The excitation signal generation unit 4018 generates, for example, a triangular wave that is an excitation signal shown in FIG. 19A from the clock supplied from the clock signal adjustment unit 403.
The excitation signal adjustment unit 4717 adjusts the voltage level of the excitation signal supplied from the excitation signal generation unit 4018 and supplies it to the excitation coil 52 as an excitation signal.

The detection coil 51 generates a pulse in the positive / negative alternating time zone of the excitation signal in the magnetic core of the magnetic element 50.
The exciting coil 52 generates a magnetic field corresponding to the triangular wave in the magnetic core of the magnetic element 50.
The detection signal amplification unit 4012 amplifies the voltage level of the pulse supplied from the detection coil 51 and outputs the amplified voltage level to the detection signal comparison unit 4013 as a detection signal.
The detection signal comparison unit 4013 obtains the difference between the time width of the pulse (detection signal) between time t1 and time t2 and T / 2, and outputs this difference to the output signal generation unit 4015.

The output signal generation unit 4015 obtains voltage information corresponding to the difference from the difference indicating the supplied time. The output signal generation unit 4015 outputs the obtained voltage information to the data signal conversion unit 4016.
The data signal conversion unit 4516 reads the magnetic field strength corresponding to the voltage value of the voltage information from the voltage value magnetic field table previously written and stored in the internal storage unit, and the strength of the magnetic field applied to the magnetic element 50. Ask for. The voltage value magnetic field table is a table showing the correspondence between the voltage value of the voltage information and the intensity of the applied stationary magnetic field Hex. A magnetic field intensity detection device (not shown) is connected to the data signal output terminal.

Further, the detection signal amplification unit 4512 in FIG. 12 has a configuration in which a switching element is provided in the same manner as the detection signal amplification unit 6011 in FIG. 1 or FIG. The excitation signal adjustment unit 4517 in FIG. 12 has a configuration in which a switching element is provided, similarly to the excitation signal adjustment unit 6016 in FIG. The data signal conversion unit 4516 in FIG. 12 controls on / off of each switching element of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 in the same manner as the data signal conversion unit 6015 in FIG. The polarity state of each of 4512 and the excitation signal adjustment unit 4517 is set.
Therefore, for example, the combination of the polar states is, for example, the type (1) in which the excitation signal adjustment unit 4517 is in the non-inversion state and the detection signal amplification unit 4512 is in the non-inversion state, and the excitation signal adjustment unit 4517 is in the inversion state. There are two types, the type (3) in which the detection signal amplification unit 4512 is in an inverted state.
The combination of the two types of type (1) and type (3) described above is an example. In the table shown in FIG. 5, if the temperature dependency of the data output error is the opposite type, for example, A circuit configuration in which any of the types (1) and (4) is combined may be employed. The following description will be made with a combination of type (1) and type (3) as an example.

  FIG. 13 is a flowchart for explaining generation of a data signal in the data signal converter 4516 when detecting a data signal in the temperature range from the temperature T0 to the characteristic temperature Ta. In FIG. 13, the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 are sequentially controlled to the type (1) and the type (3), respectively, and the type (1) and the type (3) are controlled. In each, it is a flowchart which shows the process which acquires each voltage value Vb1 and voltage value Vb3, and averages and obtains a data signal.

Step S51:
The data signal conversion unit 4516 controls the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 on and off the switching elements for changing the polarity state provided in the respective units in synchronization with the clock signal. The polarity state of type (1) is set.
Thereby, each polarity state of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 corresponds to the type (1), and the magnetic field control process already described in the magnetic element control device 400 is performed, and the output signal generation unit 4015 is performed. The output signal corresponding to the polarity state of type (1) is output as voltage value Vb1.

Step S52:
The data signal conversion unit 4516 receives the output signal (voltage value Vb1) output from the output signal generation unit 4015, and temporarily writes and stores the output signal in a storage unit provided therein.

Step S53:
The data signal conversion unit 4516 changes the polarity state of each of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 in synchronization with the clock signal in the cycle next to the cycle in step S51. The switching element for changing the state is controlled to be turned on and off, and is set to the type (3) polarity state.
As a result, the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 correspond to the type (3), the magnetic field detection processing already described in the magnetic element control device 400 is performed, and the output signal generation unit 4015 A feedback signal corresponding to the polarity state of type (3) is output as voltage value Vb2.

Step S54:
The data signal conversion unit 4516 receives the output signal (voltage value Vb3) output from the detection signal amplification unit 6011, and temporarily writes and stores the output signal in a storage unit provided therein.

Step S55:
The data signal conversion unit 4516 reads the voltage value Vb1 and the voltage value Vb3 from the storage unit provided therein, adds the voltage value Vb1 and the voltage value Vb3, divides the addition result by 2, and averages the result. .

Step S56:
The data signal conversion unit 4516 refers to the voltage value magnetic field table stored in the storage unit provided therein, obtains the intensity of the magnetic field corresponding to the averaged voltage value ((Vb1 + Vb3) / 2), and outputs the data signal Output as.

Next, another operation example of the magnetic element control device 450 according to the fourth embodiment will be described.
FIG. 14 is a flowchart for explaining generation of a data signal in the data signal conversion unit 4516 when detecting a data signal in the entire temperature range including the characteristic temperature Ta from the temperature T0. In FIG. 14, the polarity states of the detection signal amplifying unit 4512 and the excitation signal adjusting unit 4517 are sequentially controlled to the type (1) and the type (3), respectively, and the type (1) and the type (3) are controlled. In each, it is a flowchart which shows the process which acquires each voltage value Vb1 and voltage value Vb3, and averages and obtains a data signal.

From FIG. 4, the sensitivity polarities of type (1) and type (3) are the same at characteristic temperature Ta or higher, and the two types of polarities have the opposite temperature characteristics of data output error in the temperature range above specific temperature Ta. The state includes a combination of type (1) and type (3).
FIG. 14A is a flowchart for obtaining an offset value in a reference magnetic field (for example, a zero magnetic field) before the magnetic element control device 450 is shipped. The data signal conversion unit 4516 obtains the offset value obtained by the inspection before shipment for each predetermined temperature in the entire temperature range, and writes and stores it in the internal storage unit.

  FIG. 14B is a flowchart for explaining generation of a data signal in the data signal conversion unit 4516 when detecting a data signal in the entire temperature range from the temperature T0 to the characteristic temperature Ta after shipment of the magnetic element control device 450. is there. That is, in FIG. 14B, the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 are sequentially controlled to the type (1) and the type (3), respectively, and the type (1) and the type In each of (3), the voltage value Vb1 and the voltage value Vb3 are acquired and averaged to obtain a data signal.

This will be described with reference to the flowchart of FIG.
Step S61a:
An arbitrary uniform magnetic field is generated in a specific spatial region with respect to the three orthogonal directions by a coil that can apply a uniform magnetic field in the three orthogonal directions (hereinafter referred to as a “three-axis Helmholtz coil”). An environment that can be used is prepared, and a magnetic element control device 450 to which the magnetic element 50 is added is installed in the environment. A zero magnetic field is applied to the magnetic element 50.

Step S62a:
The data signal conversion unit 4516 controls the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 on and off the switching elements for changing the polarity state provided in the respective units in synchronization with the clock signal. The polarity state of type (1) is set.
As a result, the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 correspond to the type (1), the magnetic field detection processing already described in the magnetic element control device 450 is performed, and the output signal generation unit 4515. The output corresponding to the polarity state of type (1) is output as voltage value Vb1.

Step S63a:
The data signal conversion unit 4516 receives the output signal (voltage value Vb1) output from the output signal generation unit 4015, and temporarily writes and stores the output signal in a storage unit provided therein.

Step S64a:
The data signal conversion unit 4516 changes the polarity state of each of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 in synchronization with the clock signal in the cycle next to the cycle in step S51. The switching element for changing the state is controlled to be turned on and off, and is set to the type (3) polarity state.
Thereby, each polarity state of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 corresponds to the type (3), and the magnetic field detection processing already described in the magnetic element control device 450 is performed, and the output signal generation unit 4015 is performed. A feedback signal corresponding to the polarity state of type (3) is output as voltage value Vb3.

Step S65a:
The data signal conversion unit 4516 receives the output signal (voltage value Vb3) output from the output signal generation unit 4015, and temporarily writes and stores the output signal in a storage unit provided therein.

Step S66a:
The data signal conversion unit 4516 reads the voltage value Vb1 and the voltage value Vb3 from the storage unit provided inside, adds the voltage value Vb1 and the voltage value Vb3, divides the addition result by 2, and averages the result. The offset value is calculated.

  The above-described processing for obtaining the offset value from step S61a to step S66a is performed for each predetermined temperature in the entire temperature range, the offset value for each predetermined temperature in the entire temperature range is obtained, and this offset value is obtained as a data signal conversion unit. The data is written and stored in a storage unit provided inside 4516. The processing for writing the obtained offset value to the storage unit inside the data signal conversion unit 4516 may be performed by the data signal conversion unit 4516 itself, or may be performed by a computer that temporarily receives the data signal.

Next, the flowchart of FIG. 14B will be described. In the case of the operation shown in the flowchart of FIG. 14B, the operation after shipping is shown, and the magnetic element 50 is placed under a normal steady magnetic field.
Step S61:
The data signal conversion unit 4516 controls the polarity states of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 on and off the switching elements for changing the polarity state provided in the respective units in synchronization with the clock signal. The polarity state of type (1) is set.
Thereby, each polarity state of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 corresponds to the type (1), the magnetic field detection processing already described in the magnetic element control device 450 is performed, and the output signal generation unit 4015. The output signal corresponding to the polarity state of type (1) is output as voltage value Vb1.

Step S62:
The data signal conversion unit 4516 receives the output signal (voltage value Vb1) output from the output signal generation unit 4015, and temporarily writes and stores the output signal in a storage unit provided therein.

Step S63:
The data signal conversion unit 4516 sets the polarity state of each of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 in synchronization with the clock signal in the period next to the period in step S61. The switching element for changing the state is controlled to be turned on and off, and is set to the type (3) polarity state.
Thereby, each polarity state of the detection signal amplification unit 4512 and the excitation signal adjustment unit 4517 corresponds to the type (3), and the magnetic field detection processing already described in the magnetic element control device 450 is performed, and the output signal generation unit 4015 is performed. Output signal corresponding to the polarity state of type (3) is output as voltage value Vb3.

Step S64:
The data signal conversion unit 4516 receives the output signal (voltage value Vb3) output from the output signal generation unit 4015, and temporarily writes and stores the output signal in a storage unit provided therein.

Step S65:
The data signal conversion unit 4516 reads the voltage value Vb1 and the voltage value Vb3 from the storage unit provided inside, adds the voltage value Vb1 and the voltage value Vb3, divides the addition result by 2, and averages the result. Measured value data is calculated.

Step S66:
The data signal conversion unit 4516 reads temperature data from a temperature sensor (not shown) provided in the magnetic element control device 450.
Then, the data signal conversion unit 4516 refers to the offset value table stored in the internal storage unit, and reads the offset value corresponding to the temperature data. Here, when there is no offset value corresponding to the measured temperature, the data signal conversion unit 4516 performs complementation such as averaging adjacent offset values above and below the measured temperature.
The data signal converter 4516 subtracts the offset value from the voltage value ((Vb1 + Vb3) / 2) of the measurement value data to obtain corrected measurement value data.
Then, the data signal conversion unit 4516 refers to the voltage value magnetic field table stored in the internal storage unit, obtains the strength of the magnetic field corresponding to the corrected measurement value data, and outputs it as a data signal.

  Accordingly, in the present embodiment, by performing the operation of the flowchart of FIG. 13, as in the first embodiment, the sensitivity polarity is the same, and data is obtained in the temperature range from the temperature T0 to the characteristic temperature Ta. Obtain feedback signals in each of the two types of polarity states where the temperature characteristics of the output error are opposite, add the two types of feedback signals, and then average the result to obtain measurement data. From this measurement data, the magnetic field strength is obtained. ing. Therefore, according to the present embodiment, by using the operation of the flowchart of FIG. 13, the temperature dependence of the temperature coefficient of the data signal can be reduced as compared with the conventional case, that is, it can be removed by the chopping operation. This makes it possible to improve the temperature characteristics of the offset of the output value of the operational amplifier, which is difficult, and to detect the strength of the magnetic field with higher accuracy than before.

  Further, in the present embodiment, by performing the operation of the flowchart of FIG. 14, as in the first embodiment, the sensitivity polarity is the same, and the data is obtained in the entire temperature range from the temperature T0 to the characteristic temperature Ta. In each of the two types of polar states where the temperature characteristics of the output error are opposite, a zero magnetic field is obtained for each temperature in the entire temperature range, and an offset value is obtained by averaging the two types of feedback signals. The above two types of feedback signals are obtained, and after adding these two types of feedback signals, the result of subtracting the offset corresponding to the temperature at the time of measurement is used as measurement data, and the magnetic field strength is obtained from this measurement data. Yes. For this reason, according to the present embodiment, the temperature dependency of the temperature coefficient of the data signal can be reduced by using the operation of the flowchart of FIG. 14, that is, it can be removed by the chopping operation. Therefore, it is possible to improve the temperature characteristics of the offset of the output value of the operational amplifier, and to detect the strength of the magnetic field with higher accuracy than before.

  In addition, a program for realizing the functions (arithmetic processing related to magnetic element control) of each of the magnetic element control devices of FIGS. 1, 10, 11, and 12 is recorded on a computer-readable recording medium, and this recording medium The magnetic element control process may be performed by causing the computer system to read and execute the program recorded on the computer. Here, the “computer system” includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory in a computer system serving as a server or a client in that case, and a program that holds a program for a certain period of time are also included. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 50,300 ... Magnetic element 51,303 ... Detection coil 52,301 ... Excitation coil 102,402 ... Clock signal generation part 103,403 ... Clock signal adjustment part 302 ... Feedback coil 450,600,650,660 ... Magnetic element control apparatus 451, 601, 651, 661... Magnetic element control unit 500, 20173, 20176 ... Resistance 1012, 4013 ... Detection signal comparison unit 1014 ... Feedback signal conversion unit 1017, 1017 A, 4018 ... Excitation signal generation unit 4015 ... Output signal generation unit 4512 , 6011 ... Detection signal amplifying unit 4516, 6015 ... Data signal converting unit 4517, 6016, 6016A ... Excitation signal adjusting unit 6013 ... Feedback signal adjusting unit 20171, 20174 ... Amplifying circuit 20172, 20178 ... Inverting circuit 20155, 20077 Differential amplifier

Claims (13)

A magnetic element that controls the magnetic element when detecting the strength of a stationary magnetic field applied to a fluxgate type magnetic element having an excitation coil and a detection coil in a magnetic core by a time-resolved magnetic balance type Control device,
An excitation signal generator for generating an alternating signal;
An excitation signal adjusting unit that generates an alternating current signal from the alternating signal and generates an excitation signal to be applied to the excitation coil based on the alternating current signal;
A detection signal amplifying unit that amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched, and forms a detection signal;
A detection signal comparison unit for detecting a time width of the detection signal of positive voltage and negative voltage;
A feedback signal converter that converts the time width into voltage information;
A feedback signal adjustment unit that generates a feedback signal that applies a magnetic field that cancels a stationary magnetic field applied to the magnetic element from the voltage information to the excitation coil;
A data signal converter that outputs the feedback signal as a data signal indicating magnetic field strength;
Have
In the excitation signal adjustment unit or the feedback signal adjustment unit, the feedback signal is superimposed on the excitation signal,
The data signal conversion unit inverts the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. Or a non-inverted control, a combination of a plurality of data signals is generated, and the combination is output as the data signal. When detecting the strength of a stationary magnetic field applied to a fluxgate type magnetic element in which an excitation coil, a detection coil and a feedback coil are provided on a magnetic core, using a time-resolved magnetic balance type, the magnetic element is controlled. A magnetic element control device to perform,
An excitation signal generator for generating an alternating signal;
An excitation signal adjusting unit that generates an alternating current signal from the alternating signal and generates an excitation signal to be applied to the excitation coil based on the alternating current signal;
A detection signal amplifying unit that amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched, and forms a detection signal;
A detection signal comparison unit for detecting a time width of the detection signal of positive voltage and negative voltage;
A feedback signal converter that converts the time width into voltage information;
A feedback signal adjustment unit that generates a feedback signal to be applied to a feedback coil in order to generate a magnetic field that cancels a stationary magnetic field applied to the magnetic element from the voltage information;
A data signal converter that outputs the feedback signal as a data signal indicating magnetic field strength;
Have
The data signal conversion unit inverts the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. A magnetic element control device that controls whether to invert, generates a combination of a plurality of data signals, and outputs the final data signal from the combination. The data signal converter is
When the polarity of the output of the differential amplifier of each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit is inverted, the logical product of the inversion and non-inversion of the three combinations is finally non- The magnetic element control device according to claim 1, wherein a combination of inversion and non-inversion is generated so as to be inversion. The data signal converter is
When the sensitivity polarity of the data output in the combination of inversion and non-inversion of each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit is the same and is used within a predetermined temperature range, Select two combinations in which the temperature characteristics of the error of the data signal are reversed in a constant magnetic field environment in a temperature range, obtain two data signals for each combination, and average the two data signals The magnetic element control apparatus according to claim 3, wherein a result obtained by averaging and averaging is used as the final data signal. The data signal converter is
The temperature of the error of the data signal under a constant magnetic field environment in the entire temperature range of the error of the data output in the combination of inversion and non-inversion of each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit When selecting two combinations having opposite characteristics, obtaining two data signals for each combination in a zero magnetic field, averaging the two data signals, obtaining an offset value, and measuring a stationary magnetic field The magnetic signal according to claim 3, wherein an averaged result of the two data signals of the combination is obtained, and the offset value is subtracted from the averaged result to obtain the final data signal. Element control device. An alternating signal is applied to the exciting coil in a fluxgate type magnetic element in which an exciting coil and a detecting coil are provided in a magnetic core, and the alternating signal is received from the detecting coil provided in the magnetic core. Is a magnetic element control device that detects a waveform of a pulsed signal with a different polarity detected in this manner, and controls a magnetic element that detects a stationary magnetic field according to a detection interval of the pulsed signal with a different polarity.
An excitation signal generator for generating the alternating signal;
An excitation signal adjusting unit that generates an alternating current signal from the alternating signal and generates an excitation signal to be applied to the excitation coil based on the alternating current signal;
A detection signal amplifying unit that amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched, and forms a detection signal;
A detection signal comparison unit for detecting a time width of the detection signal of positive voltage and negative voltage;
A data signal converter that generates a data signal indicating the magnetic field intensity based on the time width;
Have
Control whether the polarity of the signal input to the input terminal of the differential amplifier that generates an output in each of the excitation signal adjustment unit and the detection signal amplification unit is inverted by the data signal conversion unit To generate a combination of a plurality of data signals, and output the data signal from the combination. The data signal converter is
When the polarity of the output of the differential amplifier of each of the excitation signal adjustment unit and the detection signal amplification unit is inverted, the logical product of the inversion and non-inversion of the two combinations is finally non-inverted. The magnetic element control device according to claim 6, wherein a combination of inversion and non-inversion is generated. The data signal converter is
The combination of the inversion and non-inversion of each of the excitation signal adjustment unit and the detection signal amplification unit is averaged, and the averaged result is used as the final data signal. 8. The magnetic element control device according to 7. The data signal converter is
In each inversion and non-inversion combination of the excitation signal adjustment unit and the detection signal amplification unit, two data signals are obtained for each combination in a zero magnetic field, and the two data signals are averaged to obtain an offset value. When measuring a stationary magnetic field, an averaged result of the two data signals of the combination is obtained, and the offset value is subtracted from the averaged result to obtain the final data signal. The magnetic element control device according to claim 7. The magnetic element control device according to any one of claims 1 to 9,
The magnetic detection device, wherein the data signal conversion unit outputs a signal indicating a magnetic field intensity from the data signal. A magnetic element that controls the magnetic element when detecting the strength of a stationary magnetic field applied to a fluxgate type magnetic element having an excitation coil and a detection coil in a magnetic core by a time-resolved magnetic balance type Control method,
An excitation signal generation process in which an excitation signal generation unit generates an alternating signal;
An excitation signal adjustment unit generates an alternating current signal from the alternating signal, and generates an excitation signal to be applied to the excitation coil based on the alternating current signal,
A detection signal amplifying process, wherein the detection signal amplification unit amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched;
A detection signal comparison unit in which a detection signal comparison unit detects a time width of the detection signal of positive voltage and negative voltage;
A feedback signal generating unit that converts the time width into voltage information;
A feedback signal adjustment process in which a feedback signal adjustment unit generates a feedback signal that applies a magnetic field that cancels a stationary magnetic field applied to the magnetic element from the voltage information to the excitation coil;
A data signal conversion process in which the data signal converter outputs the feedback signal as a data signal indicating the magnetic field strength;
Including
In the excitation signal adjustment unit or the feedback signal adjustment unit, the feedback signal is superimposed on the excitation signal,
The data signal conversion unit inverts the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. Or a non-inversion control, a combination of a plurality of data signals is generated, and the data signal is output from the combination as a data signal. When detecting the strength of a stationary magnetic field applied to a fluxgate type magnetic element in which an excitation coil, a detection coil and a feedback coil are provided on a magnetic core, using a time-resolved magnetic balance type, the magnetic element is controlled. A magnetic element control method to be performed,
An excitation signal generation process in which an excitation signal generation unit generates an alternating signal;
An excitation signal adjustment unit generates an alternating current signal from the alternating signal, and generates an excitation signal to be applied to the excitation coil based on the alternating current signal,
A detection signal amplifying process, wherein the detection signal amplification unit amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched;
A detection signal comparison unit in which a detection signal comparison unit detects a time width of the detection signal of positive voltage and negative voltage;
A feedback signal generating unit that converts the time width into voltage information;
A feedback signal adjustment process in which a feedback signal adjustment unit generates a feedback signal that applies a magnetic field that cancels a stationary magnetic field applied to the magnetic element from the voltage information to the feedback coil;
A data signal conversion process in which the data signal converter outputs the feedback signal as a data signal indicating the magnetic field strength;
Including
The data signal conversion unit inverts the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit, the detection signal amplification unit, and the feedback signal adjustment unit. A magnetic element control method comprising: controlling whether to invert, generating a combination of a plurality of data signals, and outputting the combination as a final data signal from the combination. An alternating signal is applied to the exciting coil in a fluxgate type magnetic element in which an exciting coil and a detecting coil are provided in a magnetic core, and the alternating signal is received from the detecting coil provided in the magnetic core. Is a magnetic element control method for detecting a waveform of a pulsed signal having a different polarity detected and controlling a magnetic element for detecting a stationary magnetic field according to a detection interval of the pulsed signal having a different polarity.
An excitation signal generation process in which an excitation signal generation unit generates the alternating signal;
An excitation signal adjustment unit generates an alternating current signal from the alternating signal, and generates an excitation signal to be applied to the excitation coil based on the alternating current signal,
A detection signal amplifying process, wherein the detection signal amplification unit amplifies a positive or negative voltage signal generated by an induced electromotive force when the current direction of the excitation signal is switched;
A detection signal comparison unit in which a detection signal comparison unit detects a time width of the detection signal of positive voltage and negative voltage;
A data signal conversion process in which the data signal conversion unit generates a data signal indicating the magnetic field intensity based on the time width;
Including
In the excitation signal adjustment unit or the feedback signal adjustment unit, the feedback signal is superimposed on the excitation signal,
Whether the data signal conversion unit inverts or non-inverts the polarity of a signal input to an input terminal of a differential amplifier that generates an output in each of the excitation signal adjustment unit and the detection signal amplification unit A magnetic element control method comprising: generating a combination of a plurality of data signals and outputting the data signal from the combination.

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