JP4434111B2 - Current sensor and current detection method - Google Patents

Description

The present invention relates to a current sensor for detecting a current flowing through a detected object including the detected object in cooperation with the detected object under magnetic detection by a magnetic detection element, and a current detection method thereof, in particular. A current sensor for detecting a current (specifically, a current amount, a direction, and the like) flowing through the detected object based on a difference value of magnetic vectors in opposite directions generated due to the current flowing through the detected object; The present invention relates to a current detection method.

  Conventionally, a current sensor that performs such differential detection has been used for the purpose of reducing the influence of disturbance (see Patent Document 1). The outline of an example of this type of current sensor will be described below with reference to FIG. In FIG. 15, (a) is a perspective view showing a schematic structure of the current sensor, and (b) is a front view of the sensor as viewed from the A viewing direction of (a).

  As shown in FIGS. 15A and 15B, in this current sensor, a vertical Hall element that detects magnetism in a direction parallel to the substrate surface (chip surface) is used as a magnetic detection element (Patent Document 2). )). More specifically, in this sensor, as shown in FIG. 15B, two integrated chips (Hall ICs) CP11 and CP12 in which vertical Hall elements are integrated are connected to an in-vehicle battery, for example. It is configured to be arranged on the front and back of a bus bar BB (detected body) made of a rod-like conductor for supplying power. That is, in this sensor, the magnetic (magnetic field) on the front and back of the bus bar BB is passed through these two integrated chips CP11 and CP12 (specifically, the vertical Hall elements mounted thereon) arranged on the front and back of the bus bar BB. To detect. The direction of magnetic detection of these integrated chips CP11 and CP12, that is, the direction parallel to the substrate surface, corresponds to the lateral (left and right) direction of FIG.

Next, the operation of this sensor will be briefly described.
That is, in such a current sensor, for example, when a current flows in the direction indicated by the arrow in FIG. 15A in the bus bar BB that is the detection target, the direction indicated by the dashed-dotted arrow in FIG. Magnetic vectors are generated in directions parallel to the substrate surface (chip surface) and in opposite directions on the front and back of the bus bar BB. Therefore, in this current sensor, each of these magnetic vectors is detected as a voltage value (Hall voltage) through the integrated chips CP11 and CP12 disposed on the front and back of the bus bar BB, thereby detecting the detected magnetic vector (voltage). The current flowing through the bus bar BB is detected (differential detection) based on the difference value. And by taking the difference value of the magnetic vector in this way, the influence of the disturbance (disturbance magnetic field) is canceled (cancelled) and removed, and the magnetic (magnetic field) caused by the current flowing through the detected body (bus bar BB). Only the signal component corresponding to) is extracted and detected.
JP 2003-262650 A Japanese Patent Laid-Open No. 1-251763

  However, in such a current sensor, a plurality of integrated chips CP11 and CP12 are indispensable, and the overall size of the sensor unit and the increase in the number of parts are inevitable.

  The present invention has been made in view of such circumstances, and a current sensor capable of performing current detection (differential detection) based on a difference value of magnetic vectors while having a simpler configuration, and a current detection method thereof The purpose is to provide.

In order to achieve such an object, in the invention described in claim 1, currents in the same direction flow.
Two and lines parallel to, and an integrated chip that two magnetic sensing element for detecting the opposite direction of the magnetic vector to each other is at least integrated to these 2 lines currents caused to flow provided, two on the basis of the difference value between the opposite directions of the magnetic vector detected through the magnetic detection element, a current sensor detecting a current flowing in the two lines, the integrated chip, the two parallel In a step space provided between the two lines, one of these two lines is on the front side and the other is on the back side, and is arranged between the two parallel lines. In addition, the two magnetic detection elements are configured to detect magnetic vectors in opposite directions generated due to current flowing through these lines.

According to such a configuration as a current sensor, current detection (differential detection) based on a difference value of magnetic vectors detected separately by two magnetic detection elements mounted on the same integrated chip. Can be performed more easily. Note that the number of magnetic detection elements provided on the integrated chip is not limited to two, but is arbitrary. If necessary, three or more magnetic detection elements are provided on the integrated chip. You may make it do.
In addition, when currents in the same direction flow through the two lines in this way, similar magnetic fields are generated in these lines. Therefore, magnetic vectors in opposite directions are generated at opposite positions (up and down, left and right) of each line, and the line located on the front side of the integrated chip and the line located on the back side of the integrated chip are different from each other (reciprocal). The magnetic vector in the direction is given to the integrated chip (specifically, each magnetic detection element mounted on the integrated chip). That is, according to such a configuration of the first aspect, current detection (differential detection) based on the difference value of the magnetic vector can be realized more easily and accurately.

  According to a second aspect of the present invention, in the current sensor according to the first aspect, the two magnetic detection elements are both vertical holes that detect a magnetic field component parallel to the wafer surface based on the Hall effect. It is desirable that the integrated chip on which the vertical Hall element is integrated is a Hall IC. By doing so, the above-described magnetic detection and thus current detection (differential detection) can be realized more easily and accurately. When a plurality of (or many) Hall elements are arranged on the same substrate (same chip), a general horizontal Hall element detects a magnetism by flowing a drive current in a direction parallel to the substrate surface. Requires a large area and is limited by space. In this respect, in the case of the above vertical Hall element, since a drive current flows in a direction perpendicular to the substrate surface, even when a plurality of them are arranged on the same substrate, the space restriction is eased and a simple structure is achieved. It becomes possible to maintain.

Moreover, this case, as according to the invention described in claim 3, the pre-SL two lines and the two magnetic detection elements, if so disposed so as to continue in the direction of the face of the integrated chip, the By obtaining a plurality of differential detection values based on magnetic vector subtraction (difference value) and averaging them, variations in detection values (errors) due to variations in the shape of two parallel lines (current paths), etc. Can be relaxed and reduced.

Further, as by the invention of claim 4, in the current sensor according to the claim 1 or 2, the pre-Symbol integrated chip, to between the two lines, inclined with respect to these two lines Even in such a structure, magnetic vectors in mutually different (reciprocal) directions are given to the integrated chip (specifically, each magnetic detection element mounted thereon). Thus, current detection (differential detection) based on the difference value of the magnetic vector can be realized more easily and accurately.

According to a fifth aspect of the present invention, in the current sensor according to any one of the first to fourth aspects, each of the magnetic vectors detected through the two magnetic detection elements is used for the integrated chip. Is detected as a voltage value, and the difference value of the magnetic vector is configured to be a differential amplification value obtained by differential amplification of the voltage value of the magnetic vector.

With such a configuration, the above-described differential detection can be easily realized with a known circuit (for example, a circuit using an operational amplifier (differential amplifier)).
In this case further, such as by the invention of claim 6, before Kitaira line two lines comprises a plurality of line pairs as a line pair, the differential amplification value for each of these line pairs It is effective to calculate and average the differential amplification values of the respective line pairs to be obtained and to detect the current flowing through the line pairs based on the calculated average values. .

  With such a configuration, it is possible to easily achieve the above-described averaging and, as a result, alleviate or reduce the variation (error) in the detected value with a known circuit (for example, a circuit using an operational amplifier (differential amplifier)). Become so.

In addition, when performing such current detection, in general, in order to simplify signal processing (various operations, etc.), the absolute values of the magnetic vectors applied to the respective magnetic detection elements mounted on the integrated chip are equal. It is desirable. Then, in terms of an absolute value equal These magnetic vectors, for example, as by the invention of claim 7, in the current sensor according to any one of the claims 1-6, before Symbol 2 lines Are effectively formed in the same shape.

Further, according to the invention according to claim 8 , in the current sensor according to any one of claims 1 to 7 , the two lines are disposed on a bar-shaped conductor and a printed board. It is more effective when applied to either one of wiring. Specifically, it is desirable to employ a rod-shaped conductor as the two lines if the current to be detected is a large current, and a wire disposed on the printed circuit board if the current is small.

On the other hand, according to the invention described in claim 9 , two magnetic vectors in opposite directions that are generated due to current flowing in two parallel lines through which current in the same direction flows are detected separately. An integrated chip in which at least magnetic detection elements are integrated is prepared, and a current for detecting a current flowing through the two lines is detected based on a difference value between oppositely detected magnetic vectors detected through the two magnetic detection elements. As a detection method, the integrated chip is placed in a step space provided between the two parallel lines, and one of the two lines is positioned on the front side and the other is positioned on the back side. while arranged so as to be sandwiched in this line, the by two magnetic detection elements, the opposite direction of the magnetic vector generated due to the current flows in the respective lines each Even in the case where the detection is performed at the same time, the magnetic vector detected by each of the two magnetic detection elements mounted on the single integrated chip is the same as in the first aspect of the invention. Current detection (differential detection) based on the difference value can be performed.

Then again, such as by the invention of claim 1 0, wherein the two magnetic detection elements, employs a vertical Hall element for detecting a magnetic field component parallel to the wafer surface on the basis of the Hall effect, and said longitudinal It is desirable to employ a Hall IC as the integrated chip in which the type Hall elements are integrated.

In this case, as according to the invention described in 請 Motomeko 1 1 Furthermore,
- pre SL current product chips, to between the two lines, a method of disposing so as to be inclined with respect to these two lines.
By adopting such a method, the same effect as that of the invention described in claim 4 can be obtained.

(First embodiment)
A first embodiment that embodies a current sensor and a current detection method according to the present invention will be described below with reference to FIGS. 1 is a perspective view showing a schematic configuration of the sensor, FIG. 2 is a front view seen from the arrow A side in FIG. 1, and FIG. 3 is a plan view seen from the arrow C side in FIG. FIG. 4 is a side view seen from the arrow B side in FIG.

As shown in FIG. 1 to FIG. 4, this current sensor also cooperates with the detection target under the magnetic detection by the magnetic detection element , that is , the current flowing through the detection target including the detection target is detected. As a magnetic detection element, a vertical Hall element that detects magnetism in a direction parallel to the substrate surface (chip surface) is employed as the magnetic detection element. However, here, two vertical Hall elements TH1 and TH2 are provided in one integrated chip (Hall IC) CP1, and predetermined signal processing (differential amplification) is performed on signals output from these vertical Hall elements TH1 and TH2. Etc.) is integrated with a circuit (not shown). In addition, a bus bar (for example, a bar conductor for power supply connected to an in-vehicle battery) that is a detection object forms two parallel lines BB1 and BB2, and the integrated chip CP1 includes these lines BB1 and BB1. It is arranged in a form sandwiched between BB2. More specifically, the integrated chip CP1 has a step space S indicated by a two-dot chain line in FIG. 2 provided between the two lines BB1 and BB2, and the line BB2 on the front side (upper side in FIG. 2). The line BB1 is disposed on the back side (lower side in FIG. 2). That is, in this sensor, the magnetic field (magnetic field) applied by the bus bar as the detection target and by the lines BB1 and BB2 is detected through the two vertical Hall elements TH1 and TH2 mounted on the integrated chip CP1. Yes. Note that the magnetic detection direction of the integrated chip CP1, that is, the direction parallel to the substrate surface, corresponds to the horizontal (left-right) direction in FIG. In the present embodiment, the two lines BB1 and BB2 are formed in the same shape (flat bar shape).

  FIG. 5A and FIG. 5B illustrate an arrangement mode of the bus bar (detected body). The shape of the bus bar BB is basically arbitrary as long as it forms two parallel lines BB1 and BB2. For example, as shown in FIG. It is possible to adopt a shape or the like in which things meet again downstream. Also, the shape of the two parallel lines BB1 and BB2 is basically arbitrary as long as it is a line (line) shape, and for example, as shown in FIG. 5B, gradually in the current direction. The shape may be widened or may be wavy.

Next, the operation of this sensor will be described.
That is, in such a current sensor, for example, when current flows in the direction indicated by the arrow in FIG. 1 (the same direction in each line) on the lines BB1 and BB2 of the bus bar that is the detection target, the current sensor is positioned on the front and back of the integrated chip CP1 Magnetic lines in directions parallel to the substrate surface (chip surface) and different from each other (reciprocal) are applied to the vertical Hall elements TH2 and TH1 by the lines BB2 and BB1 (in FIG. 2). (See dashed-dotted arrows). Therefore, in this current sensor, these magnetic vectors are detected as voltage values (Hall voltages) through the vertical Hall elements TH1 and TH2, respectively, so that the differential amplification of these detected magnetic vectors (voltage values) is performed. Based on the value, the current flowing through the bus bar constituted by the lines BB1 and BB2 is detected (differential detection). Also in this embodiment, by taking (subtracting) the difference value of the magnetic vector in this way, the influence of disturbance (disturbance magnetic field) is canceled (cancelled) and removed, and the detected object (bus bar) Only the signal component corresponding to the magnetism (magnetic field) caused by the current flowing through is extracted and detected.

As described above, according to the current sensor and the current detection method according to this embodiment, the following excellent effects can be obtained.
(1) As a differential detection type current sensor, the integrated chip CP1 is disposed so as to be sandwiched between two parallel lines BB1 and BB2 made of a bus bar (detected body). More specifically, in the chip CP1, the step space S provided between the two lines BB1 and BB2, the line BB2 is on the front side (upper side in FIG. 2), and the line BB1 is on the back side (lower side in FIG. 2). It arranges so that it may be located in the side. Thus, magnetic vectors (in opposite directions) generated due to current (current in the same direction) flowing through these lines BB1 and BB2 by the vertical Hall elements TH1 and TH2 mounted on the integrated chip CP1. 2) (see the alternate long and short dashed arrows in FIG. 2). Thereby, with only one integrated chip CP1, current detection (differential detection) based on the difference value between the magnetic vectors detected separately by the two vertical Hall elements TH1 and TH2 mounted on the chip CP1 can be performed more. It can be done easily.

  (2) Vertical Hall elements TH1 and TH2 that detect magnetic field components parallel to the wafer surface based on the Hall effect are employed as the magnetic detection elements (magnetoelectric conversion elements), and the integrated chip CP1 is a Hall IC. By doing so, the above-described magnetic detection and thus current detection (differential detection) can be realized more easily and accurately.

  (3) Two lines BB1 and BB2 consisting of bus bars (objects to be detected) are formed in the same shape (flat bar shape), so that simple signal processing (various computations, etc.) facilitates high accuracy. Current detection (differential detection) becomes possible.

  (4) In addition, the integrated chip CP1 is detected as a voltage value (Hall voltage) for each magnetic vector detected through the vertical Hall elements TH1 and TH2. Are obtained as differential amplification values by differentially amplifying the voltage values of these magnetic vectors. Thereby, the above-described differential detection can be easily realized with a known circuit (for example, a circuit using an operational amplifier (differential amplifier)).

  (5) In this embodiment, a large current is assumed as the current to be detected, and a rod-shaped conductor is employed as the bus bar (detected body). The present invention is practically particularly effective when applied to such a detection target (object to be detected).

(Second Embodiment)
Next, a second embodiment in which the current sensor and the current detection method according to the present invention are embodied will be described with reference to FIG. However, as shown in FIG. 6, the sensor according to this embodiment also basically has a structure similar to that of the sensor of the first embodiment. 1 to 4 are denoted by the same reference numerals, and only the differences from the sensor of the first embodiment will be mainly described here. FIG. 6 is a front view corresponding to FIG.

  As shown in FIG. 6, in this embodiment, two parallel lines BB1 and BB2 (line pairs) made up of bus bars as detection objects, and two vertical Hall elements TH1 and TH2, The integrated chips CP1 are arranged continuously (two in this case) in the plane direction. Then, through a known circuit (for example, a circuit using an operational amplifier (differential amplifier)), a differential amplification value is obtained for each of the line pairs, and an average value of the differential amplification values of the obtained line pairs And the current flowing through the bus bar (detected body) is detected based on the calculated average value. In this way, by obtaining a plurality of differential detection values based on the above-described subtraction (difference value) of the magnetic vector and averaging them, the detection value caused by the variation in the shape of the detection target (current path) is obtained. Variation (error) is reduced and reduced.

  As described above, according to the current sensor and the current detection method according to this embodiment, in addition to the effects similar to the effects (1) to (5) according to the first embodiment or effects equivalent thereto. In addition, the following effects can be obtained.

  (6) The bus bar (object to be detected) is configured to include a plurality of line pairs each including two parallel lines BB1 and BB2, and a differential amplification value is obtained for each of the line pairs, The average value of the differential amplification values of the respective line pairs to be obtained is calculated, and the current flowing through the detected object is detected based on the calculated average value. As a result, the variation (error) in the detection value caused by the variation in the shape of the detection target (current path) is alleviated and reduced through a known circuit (for example, a circuit using an operational amplifier (differential amplifier)). Become so.

(Other embodiments)
Each of the above embodiments may be modified as follows.
-The detected object is not limited to the above-mentioned rod-shaped conductor, and is arbitrary. For example, if the current to be detected is a small current, a wiring arranged on a printed circuit board is adopted as the detected object. You may make it do.

  In each of the above embodiments, in order to save space, a signal processing circuit (differential amplifier circuit, etc.) is also integrated in one integrated chip (Hall IC) CP1 together with the vertical Hall elements TH1 and TH2. However, this is not an essential configuration, and the signal processing circuit can be provided as a separate chip.

  In the above embodiments, the two parallel lines BB1 and BB2 are formed in the same shape, but this is not an essential configuration. Even when the lines BB1 and BB2 are formed in different shapes, if the predetermined signal processing is performed through an appropriate signal processing circuit after the magnetoelectric conversion by the magnetic detection element, the above-described effect (the effect of the above (3)). Other than the above) or similar effects.

  In each of the above embodiments, the integrated chip CP1 is transferred to the step space S provided between two parallel lines BB1 and BB2 made of a bus bar (detected body). It was set as the structure arrange | positioned so that the other might be located in the back side on the front side. However, the present invention is not limited to this configuration. For example, as shown in FIG. 7 (a front view corresponding to FIG. 2), the integrated chip CP1 is connected to the two parallel lines BB1 and BB2 having no step. It can also be set as the structure arrange | positioned so that it may incline with respect to these two lines. In this case as well, currents in the same direction flow through the two parallel lines BB1 and BB2 (see the arrows in FIG. 7). Also in this way, the magnetic vectors in the directions parallel to the substrate surface (chip surface) and different (opposite) from each other cause the vertical Hall elements TH1, TH2 mounted on the integrated chip CP1. Thus, current detection (differential detection) based on the above-described difference value of the magnetic vector is more easily and accurately realized.

  The arrangement mode of the integrated chip CP1 can also be changed as appropriate, and the chip CP1 has a gap between the lines BB1 and BB2 forming the step space S, for example, as shown in FIG. You may make it insert vertically (perpendicular to each line) into the space of the inside vertical (up-down) direction.

  -Also, the arrangement of the two parallel lines BB1 and BB2 made of the bus bar (object to be detected) can be changed as appropriate. These lines are, for example, as shown in FIG. You may make it arrange | position so that both may overlap (or there is no clearance gap between both (the horizontal direction in a figure)).

As the magnetic detection element, any element including the magnetoresistive element (MRE) and the like that is not limited to the above-described vertical Hall element can be used. Furthermore, even if it is a Hall element, not only the said vertical Hall element but a horizontal Hall element can be employ | adopted. In this case, for example, as shown in FIGS.
(A) An integrated chip CP2 in which the horizontal Hall elements YH1 and YH2 are mounted in the gap between the two parallel lines BB1 and BB2 having no step, that is, in the vertical direction (vertical direction) in FIG. Configuration that is inserted perpendicularly to the line.
Alternatively, as shown in FIG.
(B) The integrated chip CP2 having the horizontal Hall elements YH1 and YH2 mounted in the gap between the two parallel lines BB1 and BB2 having no step, that is, the space in the horizontal direction (left-right direction) in the figure (In parallel with the line).
And so on. 10 to 13 are drawings corresponding to FIGS. 1 to 4, and FIG. 14 is a front view corresponding to FIG.

  Furthermore, the number of magnetic detection elements disposed on the integrated chip CP1 is not limited to two, and is arbitrary, and if necessary, three or more magnetic detection elements on the integrated chip CP1 May be arranged.

  -The main point is that the integrated chip is sandwiched between two parallel lines of detection objects and has two magnetic detection elements mounted on the chip, and current flows through these lines. If the magnetic vectors generated in the opposite directions are separately detected, an effect similar to or equivalent to the effect (1) can be obtained.

The perspective view which shows the outline | summary of the sensor structure of this electric current sensor about 1st Embodiment of the electric current sensor and electric current detection method which concern on this invention. The front view seen from the A view arrow side in FIG. The top view seen from the C view arrow side in FIG. The side view seen from the B view arrow side in FIG. (A) And (b) is a top view which shows an example of the arrangement | positioning aspect of a bus-bar (to-be-detected body), respectively. The front view which shows the outline | summary of the sensor structure of this electric current sensor about 2nd Embodiment of the electric current sensor and electric current detection method which concern on this invention. The front view which shows the modification of the front structure of the said sensor typically. The front view which shows another modification of the same front structure typically. The front view which shows another modification of the same front structure typically. The perspective view which shows the outline | summary of the sensor structure at the time of using a horizontal Hall element as a magnetic detection element. The front view seen from the A view arrow side in FIG. The top view seen from the C view arrow side in FIG. The side view seen from the B view arrow side in FIG. The front view which shows the modification of the sensor structure typically. (A) is a perspective view which shows typically the outline | summary of this current sensor about an example of the conventional current sensor and current detection method, (b) is the front view seen from the A view arrow side in (a).

Explanation of symbols

  BB ... Bus bar, BB1, BB2 ... Line, CP1, CP2 ... Integrated chip, TH1 ... Vertical Hall element, TH2 ... Vertical Hall element, YH1 ... Horizontal Hall element, YH2 ... Horizontal Hall element.

Claims (11)

Two parallel lines through which current in the same direction flows, and at least two magnetic detection elements that individually detect magnetic vectors in opposite directions caused by current flowing through these two lines are integrated. and a reduction has been integrated chip, comprising, based on the difference value of the magnetic vector in the opposite direction detected through these two magnetic detection elements, a current sensor for detecting a current flowing through the two lines,
The integrated chip is sandwiched between the two parallel lines in a step space provided between the two parallel lines, with one of the two lines on the front side and the other on the back side. The current sensor is characterized in that the two magnetic detection elements respectively detect magnetic vectors in opposite directions that are generated due to current flowing through these lines. The two magnetic detection elements are both vertical Hall elements that detect a magnetic field component parallel to the wafer surface based on the Hall effect, and the integrated chip in which the vertical Hall elements are integrated is a Hall IC. Item 2. The current sensor according to Item 1. The two lines and the two magnetic detection elements, the current sensor according to claim 1 or 2 formed by arranged in succession in the direction of the face of the integrated chip. The integrated chip, a current sensor according to between the two lines, to claim 1 or 2 comprising disposed inclined with respect to these two lines. The integrated chip detects each magnetic vector detected through the two magnetic detection elements as a voltage value, and the difference value of the magnetic vector is obtained by differentially amplifying the voltage value of these magnetic vectors. current sensor according to any one of the resulting differential amplification value der Ru claims 1-4. The two parallel lines are composed of a plurality of line pairs, and the differential amplification value is obtained for each of the line pairs, and the average value of the differential amplification values of the obtained line pairs is obtained. current sensor according to calculate, in claim 5 that detect a current flowing through the respective line pair based on the average value issued the calculated a. The two lines, a current sensor according to any one of claims 1 to 6 have the same shape ing. The two lines, a current sensor according to any one of the rod-shaped conductors, and the printed circuit board disposed in the wiring, claims 1-7 Ru either one der of. An integrated chip is prepared in which at least two magnetic detection elements for detecting magnetic vectors in opposite directions caused by current flowing in two parallel lines through which current flows in the same direction are integrated. A current detection method for detecting a current flowing through the two lines based on a difference value of magnetic vectors in opposite directions detected through the two magnetic detection elements,
The integrated chip is moved to a step space provided between the two parallel lines, and one of the two lines is positioned on the front side and the other is positioned on the back side. In addition to being arranged so as to be sandwiched, the two magnetic detection elements detect magnetic vectors in opposite directions generated due to current flowing through these lines.
The current detection method characterized by the above-mentioned . A vertical Hall element that detects a magnetic field component parallel to the wafer surface based on the Hall effect is used as the two magnetic detection elements, and a Hall IC is used as the integrated chip in which the vertical Hall elements are integrated.
The current detection method according to claim 9 . The integrated chip, wherein the between two lines, a current detection method according to claim 9 or 10 you arranged so as to be inclined with respect to these two lines.

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