JP2000056000A - Magnetic sensor device and current sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor device and a current sensor device with wide dynamic range capable of judging the direction of magnetic field to be measured or current to be measured. SOLUTION: To a GMR element(gross magnetic field resistance) element 11, a magnetic field to be measured is impressed and a small alternating current is impressed by an alternating current power source 24 and a coil 23. The output signal of the GMR element 11 is amplified by an amplifier 13, a component corresponding to the alternating current field is removed by an LPF 14 and output from an absolute value signal output terminal 15 as an absolute value signal indicating the absolute value of the magnetic field to be measured. BPF 16 extracts a component corresponding to the alternating current magnetic field among the output signal of the amplifier 13. A phase comparator 19 compares the output signal of the BPF 16 having passed through a waveform rectifying circuit 18 and outputs a direction discriminating signal indicating the direction of the magnetic field to be measured to a direction discriminating signal output terminal 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a magnetic sensor device for measuring a magnetic field and a current sensor device for measuring a current by measuring a magnetic field generated by the current.

[0002]

2. Description of the Related Art In recent years, magnetic sensor devices for measuring a magnetic field have been widely used in magnetic application products and the like widely used in the industrial world. As an application of the magnetic sensor device, a current sensor device that measures a current in a non-contact manner by measuring a magnetic field generated by the current has been widely used. Further, in the future, as a use of the current sensor device, a use such as a non-contact measurement of a large DC current in a device handling a large DC current such as an electric vehicle or a solar battery is expected. When the current to be measured is an alternating current, it can be easily measured in a non-contact manner using a transformer. However, when the current to be measured is a direct current, a non-contact measurement of the current requires a magnetic sensor operating with a direct current magnetic field.

As a magnetic sensor (magnetic detecting element) used in a current sensor device for measuring a direct current, there are a Hall element, a magnetoresistive element, a flux gate type magnetic sensor and the like.

[0004] Among them, Hall elements are often used because of their good linearity between the magnetic field and the sensor output. However, Hall elements have the disadvantage of low output.
In a typical example of the Hall element, the output is about 10 mV at an element current of 1 mA and a magnetic flux density of 10 mT. Therefore, in a current sensor device using a Hall element, the output of the Hall element needs to be DC-amplified. However, among the amplification techniques, the DC amplification technique belongs to the technically most difficult category in consideration of the drift. Therefore, a current sensor device using a Hall element has been expensive. Conventionally, a method of avoiding a DC amplification technique by using a drive current of a Hall element as an alternating current has been widely adopted, but in this case, a rectifier circuit or the like is newly required.
The current sensor device using the Hall element becomes expensive.

[0005] The flux gate type magnetic sensor has a complicated structure and is difficult to handle, so there are few examples of application to a current sensor device. The fluxgate magnetic sensor has high sensitivity, but has a disadvantage that signal processing until obtaining a DC output is complicated. Therefore, the current sensor device using the flux gate type magnetic sensor is also expensive.

[0006] An example of the magnetoresistive element is an anisotropic magnetoresistive (AMR).
It is written. An AMR element using the effect and a GMR element using a giant magnetoresistance (hereinafter, referred to as GMR (Giant Magneto Resistive)) effect. The output of the GMR element is larger than that of the AMR element. In general,
The AMR element is simply called an MR element.

[0007] Such a magnetoresistive element has the advantage that the output is large. In particular, the GMR element is 10 m
Since the resistance change amount per T is about 5%, for example, assuming that the GMR element is driven at 1 mA in a differential configuration and the resistance of the GMR element is 10 kΩ when the magnetic field is zero, the output is obtained at a magnetic flux density of 10 mT. Is 1 V, and an output about 100 times that of the Hall element can be obtained. Therefore, by using the magnetoresistive effect element, it is possible to avoid the difficulty of DC amplification, and there is a possibility that an inexpensive current sensor device can be realized.

[0008]

SUMMARY OF THE INVENTION However, GMR
Since the element does not depend on the direction of the magnetic field,
There is a problem that the direction of the applied magnetic field (current direction in the case of a current sensor device) cannot be determined.

[0009] Such a problem also applies to an AMR element configured so that the output becomes maximum or minimum when the applied magnetic field is zero.

Conventionally, as a general method for avoiding the above-mentioned problems in the magnetoresistive element, a bias magnetic field is applied to the magnetoresistive element as disclosed in JP-A-63-277977. A method has been adopted in which a magnetic field to be measured is measured in a magnetic field region centered on a bias magnetic field by applying a voltage.

However, in this method, since the applied magnetic field including the bias magnetic field and the magnetic field to be measured is limited in one direction, the dynamic range of the sensor device is less than half of the dynamic range inherent in the magnetoresistive element. There is a problem that it becomes.

Further, in the above method, when the magnetic field to be measured is in the opposite direction to the bias magnetic field, and when the absolute value of the magnetic field to be measured exceeds the absolute value of the bias magnetic field, the element is moved with respect to the direction of the change in the magnetic field to be measured. There is a problem that the direction of the output change is reversed. Specifically, for example, when the sensor device is configured such that the output of the element increases as the magnetic field to be measured in the direction opposite to the bias magnetic field increases, the absolute value of the magnetic field to be measured becomes the absolute value of the bias magnetic field. If it exceeds, the output of the element decreases as the magnetic field to be measured increases. Therefore, when such a sensor device is used for any control system, the control system may run away when a large magnetic field to be measured is applied or when a large noise magnetic field is generated. As a method of using a current sensor device, not only measurement of the current value, but also some kind of control using the measured current value is common. There are many. That is, it can be seen that the current sensor device using the conventional bias magnetic field is very incomplete.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic sensor device and a current sensor device capable of determining the direction of a magnetic field or current to be measured and having a wide dynamic range. It is in.

[0014]

A magnetic sensor device according to the present invention comprises: a magnetic detecting element for outputting a signal corresponding to a magnetic field; AC magnetic field applying means for applying a predetermined AC magnetic field to the magnetic detecting element; Discriminating means for comparing the phase of the alternating magnetic field applied by the alternating magnetic field applying means with the phase of the component of the output of the magnetic detection element corresponding to the alternating magnetic field to determine the direction of the magnetic field to be measured. Things.

A current sensor device according to the present invention is a current sensor device for measuring a measured current by measuring a magnetic field generated by the measured current, and outputs a signal corresponding to the magnetic field generated by the measured current. A magnetic detecting element, an alternating magnetic field applying means for applying a predetermined alternating magnetic field to the magnetic detecting element, and an alternating magnetic field of the phase of the alternating magnetic field applied by the alternating magnetic field applying means and the output of the magnetic detecting element. Determining means for comparing the phase of the corresponding component and determining the direction of the current to be measured.

In these magnetic sensor devices or current sensor devices, a predetermined alternating magnetic field is applied to the magnetic detecting element by the alternating magnetic field applying means, and
The phase of the AC magnetic field applied by the AC magnetic field applying means is compared with the phase of the component of the output of the magnetic detection element corresponding to the AC magnetic field, and the direction of the measured magnetic field or the measured current is determined.

In the magnetic sensor device or the current sensor device according to the present invention, the magnetic detecting element is, for example, a magnetoresistive element.

Further, in the magnetic sensor device or the current sensor device of the present invention, an absolute value signal for generating an absolute value signal representing an absolute value of the magnetic field to be measured or the current to be measured based on the output signal of the magnetic detecting element. Generating means for switching the polarity of the absolute value signal generated by the absolute value signal generating means when the direction of the measured magnetic field or the measured current determined by the determining means is one of the positive and negative directions. Switching means may be provided. In this case, the absolute value signal generating means generates an absolute value signal representing the absolute value of the magnetic field to be measured or the current to be measured based on the output signal of the magnetic detecting element, and the polarity switching means determines the absolute value signal. The polarity of the absolute value signal generated by the absolute value signal generation means is switched when the direction of the measured magnetic field to be measured or the current to be measured is one of the positive and negative directions.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, an outline of the present invention will be described by taking a GMR element as an example of a magnetic detection element. FIG.
FIG. 4 is a characteristic diagram showing a magnetic field-resistance change characteristic of the GMR element.
In FIG. 2, the horizontal axis represents a magnetic field applied to the GMR element, and the vertical axis represents a resistance value. Note that the resistance value on the vertical axis in FIG. 2 is represented by the amount of change in the resistance value from the minimum value of the GMR element, which changes in accordance with the applied magnetic field, based on the minimum value. As shown in FIG.
The resistance value of the GMR element is greatest when the applied magnetic field is zero, and monotonically decreases with an increase in the absolute value of the applied magnetic field regardless of whether the applied magnetic field is positive or negative. G
The characteristic of the change in the resistance value of the MR element is symmetric about the position where the applied magnetic field is zero. When the value of the applied magnetic field is positive and negative, the directions of the magnetic fields are opposite to each other. Since the GMR element has the characteristics shown in FIG. 2, the direction of the applied magnetic field cannot be determined only by the resistance value.

Therefore, conventionally, as shown in FIG. 2, for example, generally, a bias magnetic field B is applied to a GMR element to generate a GM signal.
The R element was operated. In this case, since the measured magnetic field 41 is superimposed on the bias magnetic field B,
The direction of the measured magnetic field 41 is determined depending on whether the output signal of the GMR element corresponding to the resistance value of the GMR element (the voltage across the GMR element when a constant current flows through the GMR element) increases or decreases. Is done. However, as described above, if the magnetic field to be measured is in the opposite direction to the bias magnetic field and the absolute value of the magnetic field to be measured exceeds the absolute value of the bias magnetic field, the output of the GMR element will change in the direction of the change in the magnetic field to be measured. There is a problem that the direction of the signal change is reversed.

In the present invention, a minute AC magnetic field is applied to the GMR element instead of applying a DC bias magnetic field as in the related art. Here, in FIG. 2, when the measured magnetic field has a positive value P and the AC magnetic field 42 is superimposed on the measured magnetic field, the output signal of the GMR element changes as indicated by reference numeral 43. . On the other hand, when the measured magnetic field has a negative value Q and the AC magnetic field 44 is superimposed on the measured magnetic field, the output signal of the GMR element changes as indicated by reference numeral 45. Thus, when the same AC magnetic field is applied, the phase of the component corresponding to the AC magnetic field in the output signal of the GMR element is opposite to each other when the measured magnetic field has a positive value and a negative value. become. Thus, by comparing the phase of the AC magnetic field with the phase of the component of the output signal of the GMR element corresponding to the AC magnetic field, it is possible to determine the direction of the magnetic field to be measured.

The magnetic sensor device is characterized in that the object to be detected is magnetic, and unlike other sensors such as a humidity sensor, the object to be detected (magnetic field) can be electrically and arbitrarily generated. Therefore, it is very easy to superimpose an AC magnetic field on the magnetic field to be measured. According to the present invention, an AC magnetic field is applied to a GMR element, the phase of the AC magnetic field is compared with the phase of a component of the output of the GMR element corresponding to the AC magnetic field, and the direction of the magnetic field to be measured or the current to be measured is compared. Is determined.

Next, a first embodiment of the present invention will be described. FIG. 1 is a circuit diagram showing a configuration of a current sensor device including the magnetic sensor device according to the present embodiment. In the following, the current sensor device will be mainly described, but the following description also serves as the description of the magnetic sensor device.

The current sensor device according to the present embodiment comprises: a GMR element 11 having one end grounded;
And a constant current source 12 that supplies a constant current to the GMR element 11 and an amplifier 13 whose input terminal is connected to the other end of the GMR element 11. As the amplifier 13, for example, a differential amplifier is used.

The current sensor device is further provided so as to surround the conductive portion 21 through which the current to be measured passes, and has a magnetic yoke 22 partially having a gap, and a magnetic yoke 22 provided around a part of the magnetic yoke 22. An AC magnetic field application coil 23 having one end grounded and an AC power supply 24 connected to the other end of the coil 23 for generating a predetermined AC signal and supplying a small AC current to the coil 23 are provided. I have. Magnetic yoke 2
The magnetic field generated in the gap 2 is in the horizontal direction in FIG. The GMR element 11 is arranged in the gap of the magnetic yoke 22 so that the longitudinal direction is in the left-right direction in FIG. The coil 23 and the AC power supply 24 correspond to an AC magnetic field applying unit in the present invention. The coil 2
3 may be provided around the GMR element 11 instead of around a part of the magnetic yoke 22.

The current sensor device further includes a low-pass filter (hereinafter, referred to as LPF) 14 whose input terminal is connected to the output terminal of the amplifier 13 and whose output terminal is connected to the absolute value signal output terminal 15. I have. The LPF 14 is connected to the amplifier 13
, A component corresponding to the AC magnetic field is removed from the output signal.

The current sensor device further includes a band-pass filter (hereinafter, referred to as an input terminal) connected to an output terminal of the amplifier 13.
It is described as BPF. ) 16, a waveform shaping circuit 17 whose input terminal is connected to the output terminal of the BPF 16,
4 and a waveform shaping circuit 17
And a phase comparator 19 that compares a phase of the output signal of the waveform shaping circuit 18 with a phase of the output signal of the waveform shaping circuit 18 and outputs a direction determination signal indicating the direction of the measured current or the measured magnetic field to the direction determination signal output terminal 20. I have.

The BPF 16 extracts a component corresponding to the AC magnetic field from the output signal of the amplifier 13. Each of the waveform shaping circuits 17 and 18 binarizes an input signal, and is configured by, for example, a Schmitt trigger. The phase comparator 19 is constituted by, for example, an exclusive OR gate. In this case, the phase comparator 19
When the two input signals are in phase, the output signal of the phase comparator 19 is "0", and when the two input signals of the phase comparator 19 are in opposite phase, the output signal of the phase comparator 19 is "1".
Becomes When the magnetic field-resistance change characteristic of the GMR element 11 is as shown in FIG. 2, when the measured magnetic field has a positive value, the two input signals of the phase comparator 19 have opposite phases. The output signal of the device 19 becomes "1". Also,
When the magnetic field to be measured has a negative value, the two input signals of the phase comparator 19 have the same phase, so that the output signal of the phase comparator 19 is "0". Therefore, when the direction discrimination signal output from the direction discrimination signal 20 is "1", it indicates that the magnetic field to be measured has a positive value, and when it is "0", the magnetic field to be measured has a negative value. Represents Since a phase difference occurs between two input signals to the phase comparator 19 due to a difference in signal path, if necessary, phase compensation may be performed on at least one of the two input signals. Good. The phase comparator 19 corresponds to the determining means in the present invention.

Next, the operation of the current sensor device according to the present embodiment will be described. In this current sensor device, a magnetic field is generated by a measured current flowing through the conductive portion 21 in a direction perpendicular to the plane of the paper. This magnetic field is applied to the GMR element 11 disposed in the gap of the magnetic yoke 22. The magnitude of this magnetic field changes according to the magnitude of the current. Also, the direction of the magnetic field changes according to the direction of the current. The current sensor device indirectly measures the measured current by measuring a magnetic field generated by the measured current. When the device shown in FIG. 1 is used as a magnetic sensor device, the magnetic sensor device directly measures the magnetic field to be measured applied to the GMR element 11. In the following description, the magnetic field generated by the measured current is also referred to as the measured magnetic field.

A magnetic field to be measured is applied to the GMR element 11 and the AC power supply 24 and the coil 23
A small alternating magnetic field is applied. The GMR element 11 is driven by a constant current supplied from a constant current source 12, and generates an output signal corresponding to a magnetic field to be measured and an AC magnetic field.
This output signal is a voltage signal proportional to the resistance value of the GMR element 11. The output signal of the GMR element 11 is
Amplified by 3.

The output signal of the amplifier 13 is output from the absolute value signal output terminal 15 after the component corresponding to the AC magnetic field is removed by the LPF 14. The signal output from the output terminal 15 is an absolute value signal representing the absolute value of the magnetic field to be measured.

The output signal of the amplifier 13 is BPF1
6 is also input. The BPF 16 extracts a component of the output signal of the amplifier 13 corresponding to the AC magnetic field. BPF
The 16 output signals are binarized by the waveform shaping circuit 17 and input to one input terminal of the phase comparator 19. Further, the AC signal from the AC power supply 24 is binarized by the waveform shaping circuit 18 and input to the other input terminal of the phase comparator 19. Note that the phase of the AC signal from the AC power supply 24 corresponds to the phase of the AC magnetic field.

The phase comparator 19 compares the phases of the two input signals, and differs depending on whether the two input signals have the same phase or the opposite phase, and determines the direction indicating the direction of the current to be measured or the magnetic field to be measured. The signal is output to the direction determination signal output terminal 20. As shown in FIG. 2, when the same AC magnetic field is applied to the GMR element 11, the phase of the component of the output signal of the GMR element 11 corresponding to the AC magnetic field has a negative value when the measured magnetic field has a positive value. The phases are opposite to each other when the value is. Therefore,
By comparing the phase of the AC magnetic field with the phase of the component of the output signal of the GMR element 11 corresponding to the AC magnetic field by the phase comparator 19, the direction of the magnetic field to be measured or the current to be measured can be determined.

In the present embodiment, the measured value of the measured magnetic field or the measured current is determined by the absolute value signal output from the absolute value signal output terminal 15 and the direction determination signal output from the direction determination signal output terminal 20. expressed.

As described above, according to the present embodiment, an AC magnetic field is applied to the GMR element 11, and the phase of the AC magnetic field and the component of the output signal of the GMR element 11 corresponding to the AC magnetic field are changed. Since the direction of the magnetic field to be measured or the current to be measured is determined by comparing the phase, the direction of the magnetic field to be measured or the direction of the current to be measured can be determined without using a DC bias magnetic field. . Moreover, in the present embodiment, since the direction of the magnetic field applied to the GMR element 11 is not limited to one direction, a magnetic sensor device or a current sensor device having a wide dynamic range can be realized.

Further, in the present embodiment, the measured magnetic field or the measured current represented by the absolute value signal output from the absolute value signal output terminal 15 and the direction determination signal output from the direction determination signal output terminal 20. Is represented by a function that monotonically increases or decreases with changes in the magnetic field or current. Therefore, according to the present embodiment, runaway of the control system due to reversal of the direction of the change in the measured value with respect to the change in the magnetic field or the current can be prevented.

As described above, according to the present embodiment, although the sensitivity is high, the drawback of the GMR element, which is difficult to apply to the control system because the output does not depend on the direction of the applied magnetic field, is overcome. Since a measured value that is a monotonic function can be obtained over the entire range of the magnetic field to be measured in both positive and negative directions, it is possible to inexpensively realize a magnetic sensor device and a current sensor device that are highly sensitive and easy to apply to a control system. Becomes The current sensor device according to the present embodiment is extremely useful in an application such as an electric vehicle or a solar battery, which measures a large DC current in a non-contact manner, in a device handling a large DC current.

In this embodiment, the design may be changed by ordinary techniques as appropriate. For example, a bridge configuration using a plurality of GMR elements may be used to remove the offset voltage. Also, depending on the conditions, B
Instead of the PF 16, a high-pass filter may be used, or only a capacitor may be used in some cases.

Next, a second embodiment of the present invention will be described. FIG. 3 is a circuit diagram showing a configuration of the current sensor device including the magnetic sensor device according to the present embodiment. As described below, the current sensor device according to the present embodiment is different from the first embodiment in the configuration of the post-stage of the LPF 14 and the post-stage of the phase comparator 19. That is, the current sensor device according to the present embodiment includes, in the subsequent stage of the LPF 14, a switch 31 having one end connected to the output end of the LPF 14, an inverting buffer amplifier 32 having an input end connected to the other end of the switch 31, A switch 33 having one end connected to the output terminal of the LPF 14, an in-phase buffer amplifier 34 having an input terminal connected to the other end of the switch 33, and an output signal of the inversion buffer amplifier 32 and an output signal of the in-phase buffer amplifier 34 are added. And an adder 35 for outputting to an output terminal 36 of the current sensor device.

Further, the current sensor device according to the present embodiment includes, at the subsequent stage of the phase comparator 19, an inverter 37 for inverting the output signal of the phase comparator 19. In the present embodiment, the output signal of the phase comparator 19 is
The control signal of the switch 31 is input to the control input terminal of the switch 31, and the output signal of the inverter 37 is input to the control input terminal of the switch 33 as the control signal of the switch 33.

Here, when the current to be measured or the magnetic field to be measured has a positive value, the output signal of the phase comparator 19 becomes "1", and when the current to be measured or the magnetic field to be measured has a negative value, the phase comparator It is assumed that the output signal of No. 19 becomes “0”. The switch 31 closes when the output signal of the phase comparator 19, which is a control signal, is “1”, and opens when the output signal is “0”. The switch 33 is connected to the inverter 3 which is a control signal.
7 is closed when the output signal is "1" and opened when the output signal is "0".

In this embodiment, the output signal of the LPF 14 is an absolute signal representing the absolute value of the magnetic field to be measured.
The constant current source 12, the amplifier 13, and the LPF 14 correspond to an absolute value signal generation unit in the present invention. Switch 3
1. Inverting buffer amplifier 32, switch 33, in-phase buffer amplifier 34, adder 35, and inverter 37
When the direction of the magnetic field to be measured determined by the phase comparator 19 is one of the positive and negative directions, the polarity of the absolute value signal output from the LPF 14 is switched. Corresponding.

Next, the operation of the current sensor device according to this embodiment will be described. In the present embodiment, the amplifier 1
The output signal of No. 3 is input to the switches 31 and 33 after the component corresponding to the AC magnetic field is removed by the LPF 14.

Here, the output signal of the LPF 14 is adjusted by adjusting means (not shown) so that the measured magnetic field becomes zero when the measured magnetic field is zero, and the characteristic with respect to the magnetic field is, for example, the characteristic shown by a solid line in FIG. It is assumed that

When the measured current or the measured magnetic field has a positive value, the output signal of the phase comparator 19 becomes "1" and the output signal of the inverter 37 becomes "0". Therefore, the switch 31 is closed and the switch 33 is opened. As a result, L
The output signal of the PF 14 passes through the switch 31, is inverted by the inverting buffer amplifier 32, passes through the adder 35, and is output from the output terminal 36.

On the other hand, when the measured current or the measured magnetic field has a negative value, the output signal of the phase comparator 19 becomes "0" and the output signal of the inverter 37 becomes "1". Therefore, the switch 31 opens and the switch 33 closes. As a result, the output signal of the LPF 14 passes through the switch 33,
The signal is output from an output terminal 36 via an in-phase buffer amplifier 34 and an adder 35.

As a result, the characteristic of the output signal of the output terminal 36 with respect to the magnetic field is shown by a solid line in FIG. 4 when the current to be measured or the magnetic field to be measured is a negative value (when the magnetic field in FIG. 4 is negative). When the current to be measured or the magnetic field to be measured is a positive value (when the magnetic field in FIG. 4 is positive), it becomes as shown by a broken line in FIG. As described above, according to the present embodiment, the characteristics of the output signal with respect to the measured current or the measured magnetic field are monotonic over the entire range of the measured current or the measured magnetic field as the measured current or the measured magnetic field increases. Becomes a function that increases.

According to the present embodiment, the absolute value and direction of the measured current or the measured magnetic field can be represented by one output signal.

In this embodiment, the means for switching between the positive and negative polarities of the absolute value signal is not limited to the circuit configuration shown in FIG. 3, but may be another circuit configuration using a conventional technique.

Other configurations, operations, and effects of this embodiment are the same as those of the first embodiment.

The present invention is not limited to the above embodiments, but can be variously modified. For example, in each of the above embodiments, a GMR element has been described as an example of a magnetic detection element.
The present invention can be applied to the case of an element.

[0053]

As described above, according to the magnetic sensor device according to any one of claims 1 to 3 or the current sensor device according to any one of claims 4 to 6, a predetermined value is provided for the magnetic detecting element. Since the AC magnetic field is applied and the phase of the AC magnetic field is compared with the phase of the component of the output of the magnetic detection element corresponding to the AC magnetic field, the direction of the magnetic field to be measured or the current to be measured is determined. Thus, it is possible to determine the direction of the magnetic field to be measured or the current to be measured and to widen the dynamic range.

According to the magnetic sensor device of the third aspect or the current sensor device of the sixth aspect, the absolute value representing the absolute value of the measured magnetic field or the measured current based on the output signal of the magnetic sensing element. A signal is generated, and when the direction of the measured magnetic field or the measured current is either one of the positive and negative directions, the polarity of the absolute value signal is switched. There is an effect that the absolute value and direction of the measured current or the measured magnetic field can be represented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a current sensor device including a magnetic sensor device according to a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a magnetic field-resistance change characteristic of a GMR element.

FIG. 3 is a circuit diagram showing a configuration of a current sensor device including a magnetic sensor device according to a second embodiment of the present invention.

FIG. 4 is a characteristic diagram illustrating a relationship between a magnetic field to be measured and an output signal of a sensor device according to a second embodiment of the present invention.

[Explanation of symbols]

11 GMR element, 12 constant current source, 13 amplifier, 1
4 LPF, 16 BPF, 17, 18 Waveform shaping circuit, 19 Phase comparator, 22 Magnetic yoke, 23 Coil, 24 AC power supply.

Claims (6)

[Claims] A magnetic field detecting element for outputting a signal corresponding to a magnetic field; an AC magnetic field applying means for applying a predetermined AC magnetic field to the magnetic detecting element; and an AC magnetic field applied by the AC magnetic field applying means. A magnetic sensor device comprising: a determination unit configured to compare a phase with a phase of a component of the output of the magnetic detection element corresponding to the AC magnetic field to determine a direction of the magnetic field to be measured. 2. The magnetic sensor device according to claim 1, wherein the magnetic detection element is a magneto-resistance effect element. 3. An absolute value signal generating means for generating an absolute value signal representing an absolute value of a magnetic field to be measured based on an output signal of the magnetic detecting element; 3. The apparatus according to claim 1, further comprising: polarity switching means for switching between the positive and negative polarities of the absolute value signal generated by the absolute value signal generating means when the direction is one of the positive and negative directions. Magnetic sensor device. 4. A current sensor device for measuring a current to be measured by measuring a magnetic field generated by the current to be measured, comprising: a magnetic detection element for outputting a signal corresponding to the magnetic field generated by the current to be measured; AC magnetic field applying means for applying a predetermined AC magnetic field to the magnetic detecting element, and a phase of the AC magnetic field applied by the AC magnetic field applying means and a component of the output of the magnetic detecting element corresponding to the AC magnetic field. A current sensor device comprising: a determination unit configured to determine a direction of the measured current by comparing the phase with the phase. 5. The current sensor device according to claim 4, wherein the magnetic detection element is a magneto-resistance effect element. 6. An absolute value signal generating means for generating an absolute value signal representing an absolute value of a current to be measured based on an output signal of the magnetic detecting element, and an absolute value signal generating means for determining the absolute value of the current to be measured determined by the determining means. 6. The apparatus according to claim 4, further comprising: polarity switching means for switching between the positive and negative polarities of the absolute value signal generated by said absolute value signal generating means when the direction is one of the positive and negative directions. Current sensor device.