JP2007147460A - Magnetic balance type electric current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic balance type electric current sensor for further enhancing current detection accuracy. <P>SOLUTION: In this magnetic balance type electric current sensor, a secondary winding 20 includes a first wiring pattern comprising a plurality of strip-shaped first conductor patterns 21 drawn in parallel within a semiconductor substrate 1 and a second wiring pattern comprising a plurality of strip-shaped second conductor patterns 22 drawn in parallel within the semiconductor substrate 1 while being formed in parallel with the first wiring pattern. The secondary winding 20 is formed by providing each of the conductor patterns 21 with two conductive connection parts 25 for severally connecting a front end and a base end of each of the conductor patterns 21 to a front end of a conductor pattern 22 and to a base end of a second conductor pattern 22 lying next thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a current sensor that detects current using a Hall element, and more particularly to a magnetic balance type current sensor.

  2. Description of the Related Art Conventionally, current sensors that detect current using characteristics of Hall elements are known. A Hall element is an element made of a semiconductor material. When a magnetic field is applied in a direction perpendicular to the direction of the control current in a state where a control current flows in the Hall element, the magnitude of the magnetic field is increased by the development of the Hall effect. The hall voltage corresponding to the size is output. Since a magnetic field corresponding to the magnitude of the current is generated in the direction perpendicular to the direction of current flow around the current line through which the current flows, by disposing the Hall element close to the current line, The magnitude of the current can be detected. For example, as shown in FIG. 12, if the direction of the control current Ib flowing through the Hall element 100 and the current line CL are arranged close to each other, the detected current If flowing through the current line CL is changed to the Hall element. 100 can be obtained from the Hall voltage Vh generated at 100.

  However, in the method of directly detecting the detected current If flowing through the current line CL by bringing the Hall element 100 and the current line CL close to each other, a part of the magnetic flux generated around the current line CL is external space. Therefore, the detection accuracy of the detected current If is naturally limited. Therefore, a current sensor has been proposed in which magnetic flux generated around the current line CL is collected by a core made of a magnetic material such as ferrite, and has been widely put into practical use.

  As a current sensor using such a magnetic core, there are two types, a magnetic proportional type and a magnetic balance type. Among these, as shown in FIG. 13, the magnetic proportional current sensor includes an annular core 110 having a gap (gap), a Hall element 111 disposed in a gap portion 110 a of the core 110, and a Hall element 111. And an amplifier circuit 112 that amplifies the Hall voltage Vh. The current line CL is disposed in a space surrounded by the core 110 and in a direction perpendicular to the axis of the core 110. Under such a configuration, when the detected current If flows through the current line CL, a magnetic field corresponding to the magnitude of the detected current If is generated in the gap 110a of the core 110. In the magnetic proportional current sensor, the magnetic field generated in the gap 110a of the core 110 is detected as the Hall voltage Vh of the Hall element. Such a magnetic proportional current sensor has advantages such as a low manufacturing cost and a wide detection range of the detected current If because of its simple configuration, but it has a Hall voltage Vh due to the temperature dependence of the Hall element. There are also disadvantages such as a change affecting the detection accuracy of the detected current If.

  In that respect, for example, according to the magnetic balance type current sensor described in Patent Document 1, the deterioration of the detection accuracy due to the temperature dependence of the Hall element of the magnetic proportional current sensor described above is also suitably suppressed, and the detected current The detection accuracy of If can be improved. Here, a schematic configuration of this type of magnetic balanced current sensor is shown in FIG. 14, and will be described with reference to FIG.

  As shown in FIG. 14, the magnetic balanced current sensor is disposed in an annular core 120 having a gap, a secondary winding 121 wound around the core 120, and a gap portion 120 a of the core 120. The Hall element 122 is provided. The magnetic balance type current sensor is further provided with a current amplification circuit 123 that amplifies the Hall voltage Vh of the Hall element 122 and converts the amplified voltage into a current Ic. One end of the secondary winding 121 is connected to the current amplifier circuit 123, and the other end is grounded via the load resistor R. Similarly to the magnetic proportional current sensor, the current line CL is disposed in a space surrounded by the core 120 and in a direction perpendicular to the axis of the core 120. In this magnetic balance type current sensor, the winding direction of the secondary winding 121, the amplification factor of the current amplification circuit 123, and the like are the magnetic fields generated in the core 120 when the detected current If flows through the current line CL. And the magnetic field generated in the core 120 when the current Ic flows through the secondary winding 121 is set to cancel.

In the magnetic balance type current sensor having the above configuration, the Hall voltage Vh generated by the Hall element 122 according to the detected current If is first converted into the current Ic through the current amplifier circuit 123 and output to the secondary winding 121. . When the current Ic flows through the secondary winding 121 in this way, the magnetic field based on the detected current If and the magnetic field based on the current Ic, that is, a so-called cancellation magnetic field are canceled out to form an equilibrium state. At this time, if the voltage drop in the load resistor R is detected as the sensor output voltage Vs and the current Ic is detected based on the sensor output voltage Vs, the detected current If flowing through the current line CL can be detected. . According to such a magnetic balance type current sensor, the temperature drift due to the temperature dependence of the Hall element is also preferably suppressed, and the linearity between the detected current If and the sensor output voltage Vs is also good. The detected current If can be detected with high accuracy.
JP 2002-228689 A

  By the way, in the magnetic balance type current sensor as described above, the strength of the canceling magnetic field around the Hall element 122 changes depending on the positional relationship between the core 120 around which the secondary winding 121 is wound and the Hall element 122. The accuracy of current detection is greatly affected by the accuracy of the assembly position. Even if the positional accuracy is sufficiently secured at the time of assembly, the positional relationship may change over time due to, for example, the ambient temperature, and the current sensor detection accuracy may deteriorate. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a magnetic balance type current sensor capable of further improving current detection accuracy.

  In order to achieve such an object, in the invention described in claim 1, a secondary winding that generates a canceling magnetic field having a direction different from a magnetic field generated by energization of a current to be detected applied to a current line in response to energization; And having a Hall element disposed in the vicinity of the current line and the secondary winding, and energizing the secondary winding by a Hall voltage generated in the Hall element in response to a surrounding magnetic field, A magnetically balanced current for detecting the detected current based on the current flowing through the secondary winding when the magnetic field around the current line and the canceling magnetic field cancel each other around the Hall element. In the sensor, the secondary winding is integrally formed on a semiconductor substrate on which the Hall element is formed.

  In the above configuration, the secondary winding and the Hall element are formed on the same semiconductor substrate. In such a case, the current detection accuracy can be improved because the positioning of the secondary winding and the Hall element can be performed with extremely high accuracy using semiconductor process technology.

  By the way, in such a magnetic balanced current sensor, the Hall element and the secondary winding can be arranged very close to each other, so that a sufficiently strong canceling magnetic field can be generated with a small current even if the magnetic flux is not collected by the core. It can act on the element. Therefore, in the above configuration, it is possible to omit the core. Of course, when a core is required, it is possible to configure the magnetic balance type current sensor so that the core is integrally formed on the same semiconductor substrate together with the Hall element and the secondary winding.

  In this magnetic balance type current sensor, as in the invention according to claim 2, if the secondary winding is formed such that the direction perpendicular to the direction in which the detected current flows is the axial direction. Of the magnetic field generated by energizing the current to be detected to the current line, the magnetic field component in the axial direction of the secondary winding, that is, the direction parallel to the direction of the canceling magnetic field is larger, so that it is generated in the Hall element. The amount of change in Hall voltage is also increased, and the accuracy of current detection can be further improved.

  In such a magnetic balance type current sensor according to claim 1 or 2, the secondary winding includes a plurality of parallel wires extending in parallel to the inside of the semiconductor substrate, for example, according to the invention according to claim 3. A first wiring pattern comprising a strip-shaped conductor pattern, and a second wiring pattern comprising a plurality of strip-shaped conductor patterns extending in parallel with the inside of the semiconductor substrate and formed in parallel with the first wiring pattern; For each of the conductor patterns of the first wiring pattern, the tip and the base end thereof are respectively connected to the tip of the conductor pattern of the second wiring pattern and the base end of the conductor pattern of the second wiring pattern adjacent thereto. It is formed by providing two conductive connection portions to be connected. If the secondary winding is constituted by a plurality of members such as the first wiring pattern, the second wiring pattern, and the connection portion in this way, the degree of freedom with respect to the arrangement of the secondary winding in the semiconductor substrate is improved. As a result, the secondary winding can be formed in a more accurate form on the semiconductor substrate.

  Furthermore, in the magnetic balance type current sensor according to claim 3, each conductor pattern of the first wiring pattern is formed in the same layer of the semiconductor substrate as in the invention according to claim 4. If each conductor pattern of the second wiring pattern is formed on the same layer of the semiconductor substrate, the secondary winding can be more easily formed using a semiconductor process technique.

  Further, in the magnetic balance type current sensor according to claim 3 or 4, as in the invention according to claim 5, the Hall element has a longitudinal direction in which the direction of the control current is the thickness direction of the semiconductor substrate. And forming the secondary winding so that the direction orthogonal to the direction of the control current of the Hall element is the axial direction of the Hall element. This is effective from the viewpoint of suppressing the amount of current supplied to the winding. That is, if the secondary winding is formed so that the direction perpendicular to the control current direction of the vertical Hall element is the axial direction of the secondary winding, the canceling magnetic field detected by the vertical Hall element is reduced. Since the size is larger, even if the energization amount to the secondary winding is reduced, it is possible to generate a canceling magnetic field sufficient to cancel out the magnetic field around the current line and achieve an equilibrium state. Become.

In such a magnetic balanced current sensor according to claim 5, as a specific configuration of the secondary winding, for example, according to the invention according to claim 6,
(A) Both the first wiring pattern and the second wiring pattern are formed so as to be located on the same side in the thickness direction of the semiconductor substrate with respect to the Hall element.
Alternatively, as in the invention according to claim 8,
(B) The Hall element is formed so as to be positioned between the first wiring pattern and the second wiring pattern in the thickness direction of the semiconductor substrate.
And so on. Among these, when adopting the configuration of (a) above, as in the invention according to claim 7, the secondary winding has the first wiring pattern and the second wiring in the thickness direction of the semiconductor substrate. If both the wiring patterns are formed so as to be positioned on the side where the current line is disposed with respect to the Hall element, the secondary winding is disposed on the side closer to the Hall element with respect to the current line. As a result, the energization amount to the secondary winding for generating the canceling magnetic field can be further reduced. Further, according to the configuration (b), the Hall element is disposed in a region where the cancellation magnetic field generated by energization of the secondary winding is strongest. It is possible to further reduce the energization amount to the next winding.

  Further, in the magnetic balanced current sensor according to any one of claims 1 to 8, according to the invention according to claim 9, a circuit for adjusting the characteristics of the Hall element and a process for performing output processing of the Hall element If the circuit is integrally formed on the semiconductor substrate on which the Hall element is formed, the secondary winding, the Hall element and its peripheral circuit are integrated on one chip. It becomes possible to achieve both downsizing and reduction in manufacturing cost.

(First embodiment)
Hereinafter, a first embodiment in which a magnetic balance type current sensor according to the present invention is embodied will be described with reference to FIGS.

  As shown in FIG. 1, this magnetic balanced current sensor is largely based on the magnetic detection unit 10 that is close to the current line CL through which the detected current If flows and the output from the magnetic detection unit 10. And a processing circuit 30 that performs various processes for detecting the detected current If. In the present embodiment, the magnetic detection unit 10 and the processing circuit 30 are disposed on the same semiconductor substrate 1.

  Among these, the magnetic detection unit 10 includes a vertical Hall element 11 and a secondary winding 20 disposed above the vertical Hall element 11. The secondary winding 20 includes a plurality of strip-shaped first conductor patterns 21 extending in parallel inside the semiconductor substrate 1 and a plurality of strip-shaped second conductors extending in parallel inside the semiconductor substrate 1. The pattern 22 includes a connection portion 25 that electrically connects the first conductor pattern 21 and the second conductor pattern 22. The current line CL is arranged above the secondary winding 20 so that the direction of the detected current If is orthogonal to the direction of the axis O of the secondary winding 20. Hereinafter, the magnetic detection unit 10 will be described in more detail.

  FIG. 2 shows a cross-sectional structure of the magnetic detection unit 10 along the axis O of the secondary winding 20 in FIG. As shown in FIG. 2, in the magnetic detection unit 10, a first spacer layer IDL1, a second wiring pattern layer IDL2, each made of an interlayer insulating film, are provided above the base substrate 1a on which the vertical Hall elements 11 are formed. The second spacer layer IDL3 and the first wiring pattern layer IDL4 are sequentially stacked so as to be parallel to the upper surface of the base substrate 1a. In the second wiring pattern layer IDL2, the second conductor patterns 22 constituting the second wiring pattern 24 of the secondary winding 20 are embedded in the interlayer insulating film. In the first wiring pattern layer IDL4, the first conductor patterns 21 constituting the first wiring pattern 23 of the secondary winding 20 are embedded in the interlayer insulating film. That is, each first conductor pattern 21 of the first wiring pattern 23 is formed in the same layer (first wiring pattern layer IDL4) in the semiconductor substrate 1, and each second conductor of the second wiring pattern 24. The pattern 22 is formed in the same layer (second wiring pattern IDL2) in another semiconductor substrate 1 so as to be parallel to the first wiring pattern 23. A conductive connecting portion 25 (see FIG. 1) for connecting the first conductor pattern 21 and the second conductor pattern 22 is embedded in the interlayer insulating film of the second spacer layer IDL3.

  The first wiring pattern 23 and the second wiring pattern 24 of the secondary winding 20 are arranged so as to be sandwiched between the vertical Hall element 11 and the current line CL arranged above the semiconductor substrate 1. That is, in the thickness direction of the semiconductor substrate 1, the first wiring pattern 23 and the second wiring pattern 24 of the secondary winding 20 are both disposed above the current line CL with respect to the vertical Hall element 11. Has been.

  FIG. 3 shows a perspective structure of the secondary winding 20 embedded in the semiconductor substrate 1 in this way. Here, assuming that the end on the right side of each conductor pattern 21, 22 is the front end and the upper left end in the figure is the base end, each second conductor pattern 22 is straightly extended from the front end to the base end. In contrast, the first conductor pattern 21 is bent and extended in a substantially S shape so that the distal end side and the proximal end side thereof are located above the adjacent second conductor pattern 22. . And about each of these 1st conductor patterns 21, the two electroconductive connection part 25 which each connects the front-end | tip and base end to the front-end | tip of the 2nd conductor pattern 22, and the base end of the 2nd conductor pattern 22 adjacent to it. Is provided. In the present embodiment, the materials of the first conductor patterns 21 of the first wiring patterns 23, the second conductor patterns 22 of the second wiring patterns 24, and the connection portions 25 are aluminum (Al). Yes. Further, the connection portion 25 is formed as a via hole by a semiconductor process technique.

  Next, the outline of the structure and magnetic field detection principle of the vertical Hall element 11 will be described with reference to FIG. FIG. 4A schematically shows the planar structure of the vertical Hall element 11, and FIG. 4B shows the vertical Hall element 11 along L1-L1 in FIG. 4A. FIG. 4C schematically shows the cross-sectional structure of the vertical Hall element 11 along L2-L2 in FIG. 4A.

  The vertical Hall element 11 corresponds to a magnetic field component when a parallel magnetic field component is applied to the surface of the base substrate 1a in a state where a control current Ib including a component perpendicular to the surface of the base substrate 1a is supplied. This is an element that outputs a Hall voltage Vh. That is, the direction of the control current Ib in the vertical Hall element 11 is the thickness direction of the semiconductor substrate 1. Specifically, as shown in FIG. 4B, the vertical Hall element 11 has a semiconductor layer (P-sub) 12 made of, for example, P-type silicon and an N-type on the surface thereof, as shown in FIG. The buried layer BL is formed by introducing a conductive type impurity, and the semiconductor region 13 made of N-type silicon is formed thereon by epitaxial growth. The impurity concentration of the buried layer BL formed in the semiconductor layer 12 is higher than that of the semiconductor region 13.

  Among these, the semiconductor region 13 has a P-type diffusion layer 14 as a diffusion separation wall for electrically isolating the vertical Hall element 11 from the base substrate 1a as shown in FIG. A rectangular tube is formed so as to be connected to the semiconductor layer 12. In addition, P-type diffusion layers 15 and 16 are formed on the inner peripheral surface of the diffusion layer 14 so as to be connected to the buried layer BL, and the semiconductor region 13 includes the diffusion layers 14 to 16. Are divided into three regions 13a to 13c having a substantially rectangular parallelepiped shape. Of these regions 13a to 13c, three contact regions (N + diffusion layers) 17a, 17d, and 17e are formed on the surface of the region 13a located in the center so that the impurity concentration (N-type) is selectively increased. Has been. The contact regions 17a, 17d, and 17e are arranged on a straight line so that the contact region 17a is located at the center. On the other hand, a contact region (N + diffusion layer) 17b is formed in the center of the surface of the region 13b in a manner that the impurity concentration (N type) is selectively increased, and the impurity concentration is similarly formed in the center of the surface of the region 13c. Contact regions (N + diffusion layers) 17c are formed in such a manner that (N-type) is selectively enhanced. That is, the contact region 17a is disposed so as to face the contact region 17b and the contact region 17c with the diffusion layer 15 and the diffusion layer 16 therebetween. A terminal S, a terminal G1, a terminal G2, a terminal V1, and a terminal V2 are connected to the contact regions 17a to 17e, respectively. In the vertical Hall element 11, a region sandwiched between the contact region 17d and the contact region 17e in a region electrically partitioned inside the substrate of the region 17a is a so-called hole plate HP.

  Here, for example, as shown in FIG. 4C, when a constant control current Ib is passed from the terminal S to the terminal G1 and from the terminal S to the terminal G2, the control current Ib is formed on the substrate surface. The contact region 17a flows into the contact region 17b and the contact region 17c through the hole plate HP and the buried layer BL. As a result, a control current Ib mainly containing a component perpendicular to the substrate surface flows through the hall plate HP. For this reason, when the control current Ib is applied, a magnetic field including a component parallel to the substrate surface (for example, a magnetic field indicated by an arrow B in FIG. 4) is applied to the Hall plate HP of the vertical Hall element 11. Then, due to the expression of the Hall effect, as shown in FIG. 4B, a Hall voltage Vh corresponding to the magnetic field is generated between the terminal V1 and the terminal V2. Therefore, by detecting the Hall voltage Vh, a magnetic field component parallel to the substrate surface of the vertical Hall element 11, that is, the semiconductor substrate 1 is obtained.

  Each terminal S, G1, G2, V1, V2 of the vertical Hall element 11 and both ends of the secondary winding 20 are connected to the processing circuit 30, respectively. Next, a schematic configuration of the processing circuit 30 will be described with reference to FIG.

As shown in FIG. 5, the processing circuit 30 includes a control current application circuit 31, a current amplification circuit 32, a load resistor R, a detection circuit 33, and a Hall element correction circuit 34.
Each terminal S, G1, G2 of the vertical Hall element 11 is connected to the control current application circuit 31. The control current application circuit 31 includes a constant current source circuit or a constant voltage source circuit, and outputs a constant control current Ib to the terminal S.

  The current amplifier circuit 32 is connected to the terminals V1 and V2 of the vertical Hall element 11 and is connected to one end of the secondary winding 20 via the terminal IN. The current amplifier circuit 32 differentially amplifies the Hall voltage Vh detected as the potential difference between the terminal V1 and the terminal V2, and outputs a cancel current Ic proportional to the amplified voltage to the terminal IN. Specifically, the current amplification circuit 32 operates based on a comparator that differentially amplifies the input voltage from the terminals V1 and V2, and an output voltage of the comparator, and amplifies the output voltage of the comparator. And a complementary emitter follower circuit for outputting to the terminal IN. The circuit constants in the current amplifying circuit 32 are such that the magnetic field generated around the current line CL through which the detected current If flows around the vertical Hall element 11 and the cancel current Ic flows through the secondary winding 20. Is set to a value that cancels out the canceling magnetic field generated around the secondary winding 20 to achieve an equilibrium state.

  On the other hand, the other end of the secondary winding 20 is connected to a load resistor R via a terminal OUT. Both ends of the load resistor R are connected to the detection circuit 33. The detection circuit 33 detects the cancel current Ic flowing through the secondary winding 20 based on the sensor output voltage Vs that is the voltage across the load resistor R. The detection circuit 33 can detect the cancel current Ic in a state where the magnetic field generated around the current line CL and the cancel magnetic field generated around the secondary winding 20 are in an equilibrium state.

  The Hall element correction circuit 34 is connected to the vertical Hall element 11 and is a circuit for correcting (adjusting) the characteristics of the vertical Hall element 11. The Hall element correction circuit 34 is composed of an EPROM or EEPROM in which the correction coefficient of the vertical Hall element 11 is stored in advance, a fuse trim circuit, or the like.

Next, the detection procedure of the detected current If by the magnetic balance type current sensor configured as described above will be described with reference to FIG.
The magnetic balance type current sensor outputs the control current Ib to the vertical Hall element 11 through the control current application circuit 31 of the processing circuit 30 when detecting the detected current If. The control current Ib is output so as to flow downward in the thickness direction of the semiconductor substrate 1, for example, as shown in FIG.

  Here, when the detected current If flows through the current line CL in the direction shown in FIG. 6, a concentric magnetic flux is formed around the current line CL in the clockwise direction with respect to the direction in which the detected current If flows. Will occur. At this time, in the magnetic balanced current sensor, the Hall voltage Vh is output from the vertical Hall element 11 in accordance with the magnetic field generated by the detected current If. The magnetic balance type current sensor first converts the Hall voltage Vh into a cancel current Ic through the current amplifier circuit 32, and outputs the cancel current Ic to the secondary winding 20 via the terminal IN. As described above, each circuit constant in the current amplifier circuit 32 is set to a value such that the magnetic field generated around the current line CL and the canceling magnetic field generated around the secondary winding 20 are in an equilibrium state. Therefore, the cancel current Ic flows in the secondary winding 20 in the direction shown in FIG. That is, in the periphery of the vertical Hall element 11, a cancellation magnetic field having a direction different from a magnetic field generated by energization of the detected current If to the current line CL is generated by energization of the secondary winding 20.

  When the canceling current Ic is applied to the secondary winding 20, the magnetic field around the current line CL and the magnetic field around the secondary winding 20 are in an equilibrium state around the vertical Hall element 11, and the vertical hall This is continued until the Hall voltage Vh output from the element 11 becomes “0”. The magnitude of the cancel current Ic when the equilibrium state is thus formed changes according to the detected current If. Therefore, the magnetic balance type current sensor obtains the cancel current Ic at this time from the sensor output voltage Vs through the detection circuit 33, and detects the detected current If based on the cancel current Ic.

As described above, according to the magnetic balance type current sensor according to the present embodiment, the following effects can be obtained.
(1) The secondary winding 20 is formed integrally with the semiconductor substrate 1 on which the vertical Hall element 11 is formed. For this reason, since the positioning of the secondary winding 20 and the vertical Hall element 11 can be performed with extremely high accuracy using semiconductor process technology, the detection accuracy of the detected current If can be improved. Become.

  (2) Since the positioning of the secondary winding 20 and the vertical Hall element 11 can be performed with extremely high accuracy by the semiconductor process technology, the vertical Hall element 11 and the secondary winding 20 are disposed at extremely close positions. Thus, the magnetic collecting core as in the conventional magnetic balance type current sensor is omitted. For this reason, it is possible to reduce the size of the magnetic balance type current sensor and to suppress the manufacturing cost thereof.

  (3) The secondary winding 20 is arranged on the side where the current line CL is arranged with respect to the vertical Hall element 11 with the first wiring pattern 23 and the second wiring pattern 24 in the thickness direction of the semiconductor substrate 1. Formed to be positioned. The secondary winding 20 is arranged on the side closer to the vertical Hall element 11 with respect to the current line CL. For this reason, the detected current If can be detected with a smaller energization amount to the secondary winding 20 for generating the cancel magnetic field.

(4) The current amplification circuit 32 for amplifying the Hall voltage Vh from the vertical Hall element 11 or the vertical Hall element 11 on the semiconductor substrate 1 on which the secondary winding 20 and the vertical Hall element 11 are formed. Various circuits such as the Hall element correction circuit 34 for correcting the characteristics are integrally formed as the processing circuit 30. As a result, the magnetic balance type current sensor can be reduced in size and the manufacturing cost can be reduced.
(Second Embodiment)
Next, a second embodiment in which the magnetic balance type current sensor according to the present invention is embodied will be described. The structure of the magnetic balance type current sensor according to the present embodiment is basically based on the structure of the magnetic balance type current sensor according to the first embodiment. However, in the magnetic balanced current sensor according to the present embodiment, by changing the arrangement relationship between the secondary winding and the vertical Hall element, the energization amount to the secondary winding is at least around the current line. It is possible to generate a canceling magnetic field sufficient to cancel out the magnetic field and to achieve an equilibrium state. Such a magnetic balance type current sensor will be described with reference to FIGS. The configuration of the processing circuit unit of the magnetic balance type current sensor according to the present embodiment is basically the same as the configuration in the first embodiment, and therefore detailed description thereof is omitted here. And In addition, the same reference numerals are assigned to the same or similar structures as those in the first embodiment, and the description thereof is omitted.

  As shown in FIG. 7, the magnetic detection unit 40 of the present embodiment includes a vertical Hall element 11 and a secondary winding 50 formed by sandwiching the vertical Hall element 11 in the thickness direction of the semiconductor substrate. It is configured with. The current line CL is disposed above the secondary winding 50 so that the direction of the detected current If is orthogonal to the direction of the axis O of the secondary winding 50. Hereinafter, the magnetic detection unit 40 will be described in more detail.

  FIG. 8 shows a cross-sectional structure of the magnetic detection unit 40 along the axis O of the secondary winding 50 in FIG. As shown in FIG. 8, the magnetic detection unit 40 includes an interlayer insulating film above a base substrate 1a in which a second wiring pattern 24 formed as a buried layer and a vertical Hall element 11 are sequentially stacked. The spacer layer IDL10 and the wiring pattern layer IDL11 in which the first wiring pattern 23 is embedded in the interlayer insulating film are sequentially stacked. That is, the secondary winding 50 is formed such that the vertical Hall element 11 is positioned between the first wiring pattern 23 and the second wiring pattern 24 in the thickness direction of the semiconductor substrate 1. Also in the present embodiment, each first conductor pattern 21 of the first wiring pattern 23 is formed on the same layer of the semiconductor substrate 1, and the second wiring pattern 24 is formed on the same layer of the semiconductor substrate 1 other than that. Each second conductor pattern 22 is formed. The second wiring pattern 24 is formed to be parallel to the first wiring pattern 23.

  In addition, the secondary winding 50 is similar to the first embodiment in that the first conductor pattern 21 has the tip and the base end of the second conductor pattern 22 and the second conductor adjacent thereto. It is formed by providing two conductive connection portions 25a connected to the base ends of the pattern 22, respectively.

  The detection of the detected current If by the magnetic balance type current sensor having the above configuration is also basically performed according to the magnetic detection procedure by the magnetic parallel current sensor in the first embodiment. FIG. 9 shows the magnetic flux generated around the current line CL, the direction of the cancel current Ic when the detected current If flows in the direction shown in FIG. 9 according to the first embodiment, The direction of the magnetic flux of the cancel magnetic field generated around the secondary winding 50 by the cancel current Ic is shown. As shown in FIG. 9, since the vertical Hall element 11 is formed between the first wiring pattern 23 and the second wiring pattern 24, more magnetic flux is linked to the vertical Hall element 11. . For this reason, in order to cancel the magnetic field generated when the detected current If flows through the current line CL, the cancel current Ic input to the secondary winding 50 can be further reduced.

As described above, according to the magnetic balance type current sensor according to the present embodiment, the following new effects can be obtained.
(5) The secondary winding 50 is formed so that the vertical Hall element 11 is positioned between the first wiring pattern 23 and the second wiring pattern 24 in the thickness direction of the semiconductor substrate. The vertical Hall element 11 is disposed in a region where the cancellation magnetic field generated by energization of the secondary winding 50 is strongest. For this reason, it becomes possible to detect the detected current If by further reducing the energization amount to the secondary winding 50 for generating the cancel magnetic field.
(Other embodiments)
The magnetic balance type current sensor according to the present invention is not limited to the above-described embodiments, and can be implemented as, for example, the following forms obtained by appropriately changing these embodiments.

  In the first embodiment, in the thickness direction of the semiconductor substrate 1, both the first and second wiring patterns 23 and 24 constituting the secondary winding 20 are arranged with the current line CL with respect to the vertical Hall element 11. The first and second wiring patterns 23 and 24 are magnetically positioned so as to be located on the side opposite to the side on which the current line CL is disposed with respect to the vertical Hall element 11. The detection unit 10 may be configured. That is, in this case, the vertical Hall element 11 is arranged in a manner of being sandwiched between the current line CL and the secondary winding 20.

  In each of the above embodiments, the number of the first conductor patterns 21 of the first wiring pattern 23 and the number of the second conductor patterns 22 of the second wiring pattern 24, that is, the number of turns of the secondary winding 20 is arbitrary. For example, if the number of the first conductor patterns 21 and the second conductor patterns 22 is increased, a stronger canceling magnetic field can be generated around the secondary winding 20, so that a secondary for generating the canceling magnetic field is generated. The amount of current supplied to the winding 20 can be further reduced.

  In each of the above embodiments, the structure of the vertical Hall element 11 is arbitrary. For example, you may make it employ | adopt the vertical Hall element which has a structure as shown to Fig.10 (a)-(c). In this vertical Hall element, as shown in FIG. 10B, for example, a semiconductor layer (P-sub) 60 made of, for example, P-type silicon, and, for example, an N-type conductive impurity is introduced into the surface of the semiconductor layer 60. And an N-type semiconductor region (N well) 61 formed as a diffusion layer (well). Further, as shown in FIG. 10A, the planar structure is formed in this semiconductor layer 60 with a P-type diffusion layer (P well) 62 as a diffusion separation wall so as to surround the semiconductor region 61. ing. P-type diffusion layers (P wells) 63 and 64 having a diffusion depth shallower than that of the semiconductor region 61 are formed on the inner peripheral surface of the diffusion layer 62. The layers 62 to 64 are divided into three regions 61a to 61c having a substantially rectangular parallelepiped shape. Also in the vertical Hall element, three contact regions 17a, 17d, and 17e are formed in a straight line with the contact region 17a at the center on the surface of the region 61a located at the center. On the other hand, a contact region 17b is formed at the center of the surface of the region 61b, and a contact region 17c is formed at the center of the surface of the region 61c. In the vertical Hall element, a region sandwiched between the contact regions 17d and 17e in the region that is electrically partitioned inside the substrate of the region 61a is the hole plate HP. Even with a vertical Hall element having such a structure, as shown in FIG. 10C, when a constant control current Ib is passed from the terminal S to the terminal G1 and from the terminal S to the terminal G2, respectively, A control current Ib mainly including a vertical component flows through the hall plate HP. For this reason, when a magnetic field including a component parallel to the substrate (for example, a magnetic field indicated by an arrow B in FIG. 10) is applied to the Hall plate HP of the vertical Hall element in a state where the control current Ib flows. A Hall voltage Vh corresponding to the magnetic field is generated between the terminal V1 and the terminal V2. Therefore, a magnetic field component parallel to the semiconductor substrate 1 can be obtained by detecting the Hall voltage Vh. Further, in the manufacture of the vertical Hall element having such a structure, the semiconductor region 61 may be formed as a diffusion layer (well) on the surface of the semiconductor layer 60. It can be employed as a substrate for forming a vertical Hall element. For this reason, if the processing circuit 30 in each of the above embodiments is configured as a CMOS circuit, both the vertical Hall element and the processing circuit 30 can be manufactured by a CMOS process. The manufacturing process of the current sensor can be simplified.

  In addition, as shown in FIG. 11, for example, a vertical Hall element in which the terminal G2, the terminal V2, the terminal S, the terminal V1, and the terminal G1 are arranged in a straight line in this order may be adopted. . Even in this case, since the direction of the control current Ib is the thickness direction of the semiconductor substrate 1 in the vertical Hall element, the magnetic field around the current line CL and the canceling magnetic field can be effectively detected by the vertical Hall element. Can do.

  The Hall element formed on the semiconductor support substrate is not limited to a vertical Hall element. For example, the lateral Hall element may be formed on the semiconductor substrate 1 so that the direction of the control current Ib is the thickness direction of the semiconductor substrate 1. In short, as long as the direction of the control current Ib is the thickness direction of the semiconductor substrate 1, an arbitrary Hall element can be adopted.

  In each of the above embodiments, each first conductor pattern 21 of the first wiring pattern 23 is formed on the same layer of the semiconductor substrate 1, and the second wiring pattern 24 is formed on the same layer of a different semiconductor substrate 1. Each second conductor pattern 22 is formed. However, each first conductor pattern 21 of the first wiring pattern 23 and each second conductor pattern 22 of the second wiring pattern 24 are not necessarily formed in the same layer. If the secondary winding 20 is formed together with the vertical Hall element 11 inside the semiconductor substrate 1, the secondary winding 20 (50) can be formed using a semiconductor process technology. The positioning of the secondary winding 20 (50) and the vertical Hall element 11 can be performed with extremely high accuracy.

  -The material of the 1st conductor pattern 21 of the 1st wiring pattern 23, the 2nd conductor pattern 22 of the 2nd wiring pattern 24, or the material of the connection part 25 is not limited to aluminum (Al). For example, polycrystalline silicon may be adopted as at least one material of the first conductor pattern 21 and the second conductor pattern 22. In each of the above embodiments, the connection portion 25 is formed as a via hole by a semiconductor process technique. Instead of this, the connecting portion 25 may be formed as a contact layer.

  -In each said embodiment, arbitrary shapes are employ | adopted as each shape of the 1st conductor pattern 21 of the 1st wiring pattern 23, the 2nd conductor pattern 22 of the 2nd wiring pattern 24, and the connection part 25 (25a). can do. The secondary winding 20 (50) is connected to the tip end and the base end of each of the first conductor patterns 21 to the tip end of the second conductor pattern 22 and the base end of the second conductor pattern 22 adjacent thereto, respectively. What is necessary is just to form by providing the one electroconductive connection part 25 (25a). As long as the configuration of the secondary winding 20 (50) is ensured, the shapes of the first conductor pattern 21, the second conductor pattern 22, and the connecting portion 25 (25a), which are constituent members, may be arbitrary. it can.

  In each of the above embodiments, the direction in which the detected current If flows in the secondary winding 20 (50) so that the magnetic field around the current line CL is more effectively detected by the vertical Hall element 11 The current line CL is disposed so that the direction of the axis O of the secondary winding 20 (50) is orthogonal to the direction of the axis O. However, when a sufficiently large magnetic field is generated around the current line CL, the flowing direction of the detected current If and the direction of the axis O of the secondary winding 20 (50) are not necessarily orthogonal to each other. May be.

  In the magnetic balance type current sensor according to each of the above embodiments, the vertical Hall element 11 and the secondary winding 20 are arranged at very close positions, thereby collecting the magnetic flux in the conventional magnetic balance type current sensor. The core is omitted. However, when there are various circumstances such as a weak magnetic field detected by the vertical Hall element 11, the core and the semiconductor substrate are combined with the vertical Hall element 11 and the secondary winding 20 (50) as necessary. 1 may be integrally formed.

The top view which shows the schematic structure about 1st Embodiment of the magnetic balance type current sensor concerning this invention. Sectional drawing which shows the cross-section of the magnetic detection part along the axial center O of the secondary winding in FIG. The perspective view which shows the perspective structure about the secondary winding of the magnetic balance type current sensor concerning the embodiment. (A) is a plan view of the vertical Hall element, (b) is a cross-sectional view showing a cross-sectional structure of the vertical Hall element along L1-L1 in FIG. (A), and (c) is a diagram (a). Sectional drawing which shows the cross-section of the vertical Hall element along L2-L2 in the inside. The block diagram which shows the schematic structure about the processing circuit of the magnetic balance type current sensor concerning the embodiment. Sectional drawing which shows the cross-section of the magnetic detection part along the axial center O of the secondary winding in FIG. The top view which shows the schematic structure about 2nd Embodiment of the magnetic balance type current sensor concerning this invention. Sectional drawing which shows the cross-sectional structure of the magnetic detection part along the axial center O of the secondary winding in FIG. Sectional drawing which shows the cross-section of the magnetic detection part along the axial center O of the secondary winding in FIG. (A) is a top view of the vertical Hall element which comprises the magnetic balance type current sensor concerning other embodiment, (b) is the same vertical Hall element along L1-L1 in FIG. Sectional drawing which shows the cross-sectional structure of (2), (c) is a cross-sectional view showing the cross-sectional structure of the vertical Hall element along L2-L2 in FIG. The schematic diagram which shows the arrangement | sequence of each terminal of a vertical Hall element about the magnetic balance type current sensor concerning other embodiment. The perspective view which shows schematic structure of a direct detection type current sensor. The perspective view which shows schematic structure of the direct detection type current sensor using the core for magnetism collection. The perspective view which shows schematic structure of the conventional magnetic balance type current sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate, 1a ... Base substrate, 10, 40 ... Magnetic detection part, 11 ... Vertical Hall element, 20, 50 ... Secondary winding, 21 ... 1st conductor pattern, 22 ... 2nd conductor pattern, 23 ... 1st wiring pattern, 24 ... 2nd wiring pattern, 25, 25a ... Connection part, 30 ... Processing circuit, 31 ... Control current application circuit, 32 ... Current amplification circuit, 33 ... Detection circuit, 34 ... Hall element correction circuit, R ... load resistance, IDL ... insulating film, IDL1 ... first spacer layer, IDL2 ... second wiring pattern layer, IDL3 ... second spacer layer, IDL4 ... first wiring pattern layer, IDL10 ... spacer layer, IDL11 ... wiring pattern layer, CL: Current line.

Claims (9)

A secondary winding that generates a canceling magnetic field having a different direction with respect to a magnetic field generated by energization of a current to be detected to be applied to the current line, and disposed in the vicinity of the current line and the secondary winding. And a current applied to the secondary winding by a Hall voltage generated in the Hall element in response to a surrounding magnetic field, and the magnetic field around the current line and the cancellation around the Hall element. In a magnetic balance type current sensor that detects the detected current based on a current that flows in the secondary winding when an equilibrium state in which a magnetic field is canceled is achieved.
The magnetic balance type current sensor, wherein the secondary winding is integrally formed on a semiconductor substrate on which the Hall element is formed. 2. The magnetic balanced current sensor according to claim 1, wherein the secondary winding is formed such that a direction orthogonal to a direction in which the current to be detected flows is an axial center direction. A first wiring pattern comprising a plurality of strip-shaped conductor patterns extending in parallel to the inside of the semiconductor substrate;
A plurality of strip-shaped conductor patterns extending in parallel with the inside of the semiconductor substrate, and a second wiring pattern formed in parallel with the first wiring pattern;
With
For each of the conductor patterns of the first wiring pattern, two conductors that connect the leading end and the base end to the leading end of the conductor pattern of the second wiring pattern and the base end of the conductor pattern of the second wiring pattern adjacent thereto, respectively. The magnetic balance type current sensor according to claim 1, wherein the secondary winding is formed by providing a sexual connection portion. 4. The conductor patterns of the first wiring pattern are formed on the same layer of the semiconductor substrate, and the conductor patterns of the second wiring pattern are formed on the same layer of the semiconductor substrate different from the first wiring pattern. Magnetic balanced current sensor. The Hall element is a vertical Hall element in which the direction of the control current is the thickness direction of the semiconductor substrate,
5. The magnetic balanced current sensor according to claim 3, wherein the secondary winding is formed such that a direction orthogonal to a direction of the control current of the Hall element is an axial direction thereof. The secondary winding is formed such that both the first wiring pattern and the second wiring pattern are positioned on the same side in the thickness direction of the semiconductor substrate with respect to the Hall element. 2. A magnetic balance type current sensor according to 1. The secondary winding is formed such that both the first wiring pattern and the second wiring pattern in the thickness direction of the semiconductor substrate are positioned on the side where the current line is disposed with respect to the Hall element. The magnetic balance type current sensor according to claim 5. The magnetic circuit according to claim 5, wherein the secondary winding is formed so that the Hall element is positioned between the first wiring pattern and the second wiring pattern in the thickness direction of the semiconductor substrate. Balanced current sensor. The magnetic balance type according to claim 1, wherein a circuit for adjusting characteristics of the Hall element and a circuit for performing output processing of the Hall element are integrally formed on a semiconductor substrate on which the Hall element is formed. Current sensor.

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