JP6234263B2 - Current sensor - Google Patents

Description

  The present invention relates to a current sensor having a magnetoelectric conversion element.

  It is known that a current sensor has a magnetoelectric conversion element, for example, and outputs a signal having a magnitude proportional to a magnetic field generated by a current flowing through a conductor. For example, in Patent Document 1, a current sensor is provided that includes a substrate and a plurality of magnetic field transducers provided on the substrate, that is, a magnetoelectric conversion element and a current conductor, and the plurality of magnetoelectric conversion elements detect a current flowing through the current conductor. It is disclosed.

International Publication No. 2006/130393 Pamphlet

  In the current sensor disclosed in Patent Document 1, a plurality of magnetoelectric transducers perform current detection processing based on magnetic flux in the same direction. That is, in this current sensor, the current is detected without being based on the difference between the outputs of the respective magnetoelectric conversion elements. Therefore, when a disturbance magnetic field is applied, the detected current is easily affected by the external magnetic field. .

  That is, in this conventional current sensor, a configuration for canceling the influence of the external magnetic field by using the difference between the outputs of the magnetoelectric conversion elements has not been achieved.

  In addition, the current sensor of Patent Document 1 has a configuration in which a primary conductor through which a current to be measured flows and a secondary conductor on which a signal processing IC is disposed are placed apart from each other, and thus the size can be reduced. Is difficult. Furthermore, the withstand voltage of the current sensor is still insufficient.

  The present invention has been made in view of such circumstances, and an object of the present invention is to arrange a plurality of magnetoelectric conversion elements at positions where the influence of an external magnetic field can be canceled and to improve the withstand voltage. An object of the present invention is to provide a small-sized current sensor that can be used.

  A current sensor for solving the above problems includes a plurality of magnetoelectric transducers that detect magnetic flux, a conductor through which a current to be measured flows, a signal processing IC that processes an output from the magnetoelectric transducer, and a signal terminal. A lead frame, and the conductor includes a first conductor portion and a second conductor portion formed through a step from the first conductor portion, and each of the magnetoelectric conversion elements includes the lead frame. Arranged on both sides of the second conductor portion with the second conductor portion interposed therebetween, and the signal processing IC is supported by a fixing portion formed through a step from the lead frame. The first conductor portion is disposed over the first conductor portion.

  In addition, a current sensor for solving the above problems forms a magnetoelectric conversion element that detects magnetic flux, a conductor through which a current to be measured flows, a signal processing IC that processes output from the magnetoelectric conversion element, and a signal terminal. A lead frame, and the conductor includes a first conductor portion and a second conductor portion formed above the first conductor portion through a step from the first conductor portion in a cross-sectional view. The magnetoelectric conversion elements are arranged on both sides of the second conductor portion on an insulating sheet supported by the lower surface of the lead frame with the second conductor portion interposed therebetween, and the signal processing IC is connected to the lead frame. It is supported by a fixed portion formed above in a cross-sectional view through a step, and is disposed across the first conductor portion.

  Here, the conductor may further include a third conductor portion formed through a step from the second conductor portion.

  The signal processing IC may be arranged so that both sides of the signal processing IC are supported by at least two fixing portions formed through a step from the lead frame and straddle over the first conductor portion. .

  The insulating sheet may be supported on the lower surface of the lead frame in a non-contact state with the second conductor portion.

  The second conductor portion may be narrower than the first conductor portion and the third conductor portion.

  In addition, a current sensor for solving the above problems forms a magnetoelectric conversion element that detects magnetic flux, a conductor through which a current to be measured flows, a signal processing IC that processes output from the magnetoelectric conversion element, and a signal terminal. A center portion of the conductor is formed above a step in a cross-sectional view, and the magnetoelectric conversion element is formed on the insulating sheet supported on the lower surface of the lead frame. The signal processing IC is supported by a fixed portion formed in a cross-sectional view above the lead frame through a step from the lead frame, and the other than the central portion. It is arranged across the conductor.

  In addition, a current sensor manufacturing method for solving the above problems includes a step of forming a conductor through which a current to be measured flows and a lead frame having the shape of a signal terminal, and bending a central portion of the conductor. Alternatively, a step of bending upward in a cross-sectional view by crushing, and a fixing part formed with a step in the cross-sectional view by bending or crushing a part of the lead frame, A step of forming on both sides of the conductor apart from the conductor, and attaching an insulating sheet to the back surface of the other part of the lead frame to insulate in a direction below the central portion and across the central portion Fixing the sheet to the lead frame, placing the magnetoelectric conversion element on both sides of the insulating sheet on both sides of the central portion of the conductor, placing the signal processing IC on the fixing portion, and Other than the center A step of straddling over the conductor; a step of electrically connecting the magnetoelectric conversion element and the signal processing IC; and a lead frame serving as the signal processing IC and the signal terminal with a conductive wire; and the magnetoelectric Sealing at least part of the conversion element, the insulating sheet, the signal processing IC, the lead frame, and at least part of the conductor with a sealing resin.

  According to the current sensor of the present invention, it is possible to arrange a plurality of magnetoelectric conversion elements at a position where an external magnetic field can be canceled and to improve the withstand voltage.

It is a figure which shows an example of the internal structure of the current sensor which concerns on Embodiment 1. FIG. It is a figure which shows an example of the cross section inside the current sensor of FIG. It is a functional block diagram which shows the example of an internal structure of signal processing IC. It is a figure which shows an example of the package external appearance of the current sensor of FIG. It is a figure which shows an example of the preparation methods of the current sensor of Embodiment 1. It is a figure which shows an example of the internal structure of the current sensor which concerns on Embodiment 2. FIG. It is a figure which shows an example of the cross section inside the current sensor of FIG. It is a figure which shows an example of the internal structure of the current sensor which concerns on Embodiment 3. It is a figure which shows an example of the cross section inside the current sensor of FIG. It is a figure which shows an example of the package external appearance of the current sensor of FIG. In Embodiment 1, it is a figure which shows the structural example of the protrusion part which protrudes from a 1st conductor part. In Embodiment 1, it is a figure which shows the structural example of the protrusion part which protrudes from a 3rd conductor part.

  Hereinafter, a mode for carrying out a current sensor of the present invention (hereinafter referred to as “embodiment”) will be described with reference to the drawings.

  In addition, this invention is not limited to the following embodiment, The various change within the range which does not deviate from the summary is included. In the drawings, positional relationships such as up, down, left and right are based on the positional relationships shown in the drawings unless otherwise specified. The dimensional ratio of the constituent elements according to the embodiment is not limited to the illustrated ratio.

<Embodiment 1>
First, the configuration of the current sensor 1 of the present embodiment will be described with reference to FIGS. The current sensor according to the embodiment includes a magnetoelectric conversion element such as a Hall element, a conductor through which a current to be measured flows, a signal processing IC that processes an output from the magnetoelectric conversion element, and a lead frame that forms a signal terminal. A current sensor package (hereinafter simply referred to as “package”) in which these components are sealed.

[Configuration of Current Sensor 1]
FIG. 1 is a diagram illustrating an example of an internal structure of the current sensor 1 according to the first embodiment. 2 is a cross-sectional view of the inside of the current sensor 1, wherein (a) is a cross-sectional view taken along the line AA ′ shown in FIG. 1, (b) is a cross-sectional view taken along the line BB ′ shown in FIG. CC cross section shown in FIG. 1, (d) shows the DD 'cross section shown in FIG. In the following description, the front side (positive X direction side) in FIG. 1 is referred to as the upper side, and the rear side (negative X direction side) in FIG. 1 is referred to as the lower side. 2A to 2D, the upper side in the figure is referred to as the upper side, and the lower side is referred to as the lower side.

  1 includes a magnetoelectric conversion elements 13a and 13b that detect magnetic flux, a conductor 10 through which a current to be measured flows, a signal processing IC 20 that processes output from the magnetoelectric conversion elements 13a and 13b, and a signal terminal 41. The lead frame 100 to be formed, conducting wires 60a and 60b that electrically connect the magnetoelectric conversion elements 13a and 13b and the signal processing IC 20, and an insulating sheet 14 that supports the magnetoelectric conversion elements 13a and 13b are provided. As the conducting wires 60a and 60b, for example, metal wires or wires are used.

  The magnetoelectric conversion elements 13a and 13b arranged on both sides of the conductor 10 are elements that detect a magnetic flux density generated by the current I to be measured and output an electrical signal corresponding to the magnetic flux density to the signal processing IC 20. Examples of the magnetoelectric conversion elements 13a and 13b include a Hall element, a magnetoresistive element, a Hall IC, and a magnetoresistive IC. The number of magnetoelectric transducers is not limited to the two illustrated in FIG. 1, and may be three or more.

  As shown in FIG. 1, the conductor 10 has three conductor portions, that is, a first conductor portion 10a, a second conductor portion 10b, and a third conductor portion 10c, as shown in FIG. In addition, the second conductor portion 10b corresponding to the central portion of the conductor 10 is formed upward from the first conductor portion 10a via the step 31, and the third conductor portion 10c is downward from the second conductor portion 10b via the step 31. Formed.

  The conductor 10 is formed in a straight line shape (I shape) as shown in FIG. Therefore, the total length of the current path through which the current to be measured I flows is shortened. Thereby, since the resistance value of the conductor 10 becomes small, power loss can be suppressed and internal heat generation can also be suppressed, so that it is possible to cope with high temperatures.

  In FIG. 1, the conductor width W2 of the second conductor portion 10b is preferably set to be narrower than the conductor widths W1 and W3 of the other conductor portions. With this configuration, the current to be measured I flowing through the second conductor portion 10b is concentrated on the conductor width W2, and as a result, the magnetic flux density around the second conductor portion 10b is increased, and the S / S of the magnetoelectric transducers 13a and 13b is increased. N ratio is improved. Note that the shape of each of the conductor portions 10a to 10c is not limited to the shape shown in FIG. 1, and may be changed as appropriate. Further, the width of the second conductor portion 10b may be formed to be narrowed stepwise or continuously.

  The signal processing IC 20 amplifies or calculates the output from the magnetoelectric conversion elements 13a and 13b, and outputs a signal corresponding to the current to be measured to the signal terminal 41 as an electric signal. As shown in FIGS. 2A, 2C, and 2D, the signal processing IC 20 is disposed above the first conductor portion 10a. The signal processing IC 20 is configured by, for example, an LSI (Large Scale Integration), and includes, for example, a memory, a processor, a bias circuit, a correction circuit, an amplification circuit, and the like.

  In the lead frame 100 that forms the signal terminal 41, the signal terminal 41 is electrically connected to the signal processing IC 20 by a conducting wire 50. As the conducting wire 50, for example, a metal wire or a wire is used. The number and shape of the signal terminals 41 are not limited to those shown in FIG.

  As shown in FIG. 2B, the insulating sheet 14 is supported on the back surface of the lead frame 100, and the magnetoelectric conversion elements 13 a and 13 b are disposed on the insulating sheet 14. Examples of the insulating sheet 14 include an insulating sheet such as a polyimide tape.

  In addition, as a die attach material for arrange | positioning the magnetoelectric conversion elements 13a and 13b on the said insulating sheet, insulating materials, such as a die attach film, are mentioned, for example.

  The magnetoelectric conversion elements 13a and 13b are electrically connected to the signal processing IC 20 via the conducting wires 60a and 60b, and the signal processing IC 20 is electrically connected to the signal terminal 41 via the conducting wire 50.

  Each signal terminal 41 is configured to take out the output (current value, voltage value, etc.) of the signal processing IC 20.

  In FIG. 1, each of the protrusions 16 is formed to protrude from a conductor portion other than the second conductor portion 10b, that is, the first conductor portion 10a and the third conductor portion 10c. The protruding portion protrudes so as to surround the magnetoelectric conversion elements 13a and 13b. Note that there is a clearance between the protruding portions protruding from the first conductor portion 10a and the third conductor portion 10b. Note that the current sensor 1 may be configured not to provide the protrusion 16.

  When a low elastic material for buffering a change in package stress is applied to the surfaces of the magnetoelectric conversion elements 13a and 13b in the manufacturing process described later by the protrusion 16 described above, the protrusion 16 and the second conductor portion are applied by the surface tension. The low elastic material can be applied to the surfaces of the magnetoelectric transducers 13a and 13b without protruding the low elastic material from the area surrounded by 10b. Thereby, it becomes possible to suppress variation in the amount of the low elastic material applied to the surfaces of the magnetoelectric conversion elements 13a and 13b.

  FIG. 3 is a functional block diagram of an example of the signal processing IC 20. The signal processing IC 20 includes a bias circuit 201, a correction circuit 202, and an amplifier circuit 203. The bias circuit 201 is connected to the magnetoelectric conversion elements 13a and 13b and supplies power to the magnetoelectric conversion elements 13a and 13b. In other words, the bias circuit 201 is a circuit for applying (inflowing) an excitation current to the magnetoelectric conversion elements 13a and 13b.

  The correction circuit 202 calculates the current value by canceling the influence of the magnetic field generated externally (cancelling in-phase noise) based on the difference between the outputs of the magnetoelectric conversion elements 13a and 13b. In this case, assuming that the gain coefficient of the magnetoelectric conversion elements 13a and 13b is k, the input of the magnetoelectric conversion element 13a is s1, and the input of the magnetoelectric conversion element 13b is s2, the correction circuit 202 of {k · (s1−s2)} From the relationship, the current value is calculated by canceling the influence of the external magnetic field.

  The correction circuit 202 corrects the output values of the magnetoelectric conversion elements 13a and 13b according to a temperature correction coefficient stored in advance in a memory based on, for example, the operating temperature. For this reason, current detection with low temperature dependence and high accuracy is possible.

  The amplifier circuit 203 amplifies the output value from the correction circuit 202.

  4A and 4B are views showing an example of the external appearance of the package of the current sensor 1. FIG. 4A is a top view of the package, and FIG. 4B is a side view of the package.

  As shown in FIGS. 4A and 4B, the current sensor 1 is a quadrangular package sealed with a mold resin 80 such as an epoxy resin.

  The measured current terminals 12a and 12b and the signal terminal 41 are taken out from the four side surfaces of the package. In the example of FIG. 4, the measured current terminals 12a and 12b and the signal terminal 41 are taken out from the four side surfaces of the package. However, the present invention is not limited to this. A signal terminal is arranged on a side surface (one side or both sides) in a direction orthogonal to the signal terminal, a current input / output terminal to be measured is arranged on one side surface of the package, and the signal terminal The configuration is such that the current input / output terminals to be measured are arranged on one side of the package and the signal terminals are arranged on the other side in addition to the package side facing the one side. May be.

  In the current sensor 1, the magnetoelectric conversion elements 13 a and 13 b are disposed on both sides of the second conductor portion 10 b with the second conductor portion 10 b interposed on the insulating sheet 14 supported on the back surface of the lead frame 100. Since the magnetoelectric conversion elements 13a and 13b are arranged on both sides of the conductor 10, the direction of the magnetic flux in which the current I to be measured is generated has a reverse polarity (negative or positive Z direction). By subtracting or taking the difference between these signals having opposite polarities, the disturbance magnetic field can be canceled and a high S / N can be obtained.

  Further, each of the magnetoelectric conversion elements 13a and 13b is disposed apart from the conductor 10, and is not in contact with the conductor 10 through which the current I to be measured always flows. Thereby, the conductor 10 and the magnetoelectric conversion elements 13a and 13b are not electrically connected, and a gap (clearance) for maintaining insulation is secured.

  The signal processing IC 20 is supported by a fixing portion 30 formed with a step 31 above the lead frame 100, and is disposed across the first conductor portion 10a. The step 31 is formed above the lead frame 100 in a sectional view. The width of the fixing portion 30 is preferably wider than the signal terminal 41 from the viewpoint of strength. The width of the fixing unit 30 is preferably larger than the width of the signal processing IC 20 or set in the same manner as the width of the signal processing IC 20. The signal processing IC 20 is not limited to the example shown in FIGS. 1 and 2 and may be supported by a plurality of fixing units 30.

  The insulating sheet 14 is preferably supported on the lower surface (back surface) of the lead frame 100. In the present embodiment, the lower surface of the lead frame 100 corresponds to the rear surface side of the surface on which the signal processing IC 20 is mounted. As in the example of FIGS. 1 and 2B, the insulating sheet 14 is preferably supported on the lower surface (back surface) of the lead frame 100.

  In FIG. 2A, the fixing portion 30 has a step 31 formed above the lead frame 100 having the signal terminal 41, and the signal processing IC 20 is supported from both sides of the signal processing IC 20 by the fixing portion 30. Yes. In FIG. 2B, the signal processing IC 20 is disposed above the first conductor portion 10a. However, as illustrated in FIG. Since they are separated visually, the withstand voltage is improved. A mold resin 80 is filled between the signal processing IC 20 and the first conductor portion 10a.

  In FIG. 2B, the insulating sheet 14 is supported on both sides of the insulating sheet 14 on the back surface of the lead frame 100, and is disposed below the second conductor portion 10b. On this insulating sheet 14, as shown in FIG. 1, the magnetoelectric conversion elements 13a and 13b are arranged on both sides of the second conductor portion 10b with the second conductor portion 10b interposed therebetween. Thereby, the height position of the magnetosensitive surfaces of the magnetoelectric conversion elements 13a and 13b can be set between the height from the bottom surface to the top surface of the lead frame 100 (that is, between the thicknesses of the conductors 10). Preferably, the height position of the magnetosensitive surfaces of the magnetoelectric conversion elements 13a and 13b is set near the center between the height from the bottom surface to the top surface of the lead frame 100. As a result, more magnetic flux generated by the measured current I flowing in the current path of the conductor 10 can be captured on the magnetosensitive surfaces of the magnetoelectric conversion elements 13a and 13b, and as a result, current detection sensitivity is improved.

  In FIG. 1 and FIG. 2 (d), in the conductor 10, the second conductor portion 10 b is formed upward from the first conductor portion 10 a through the step 31, and the second conductor portion 10 b is formed downward from the second conductor portion 10 b through the step 31. A three-conductor portion 10c is formed. As shown in FIG. 2D, the second conductor portion 10b is located above the first conductor portion 10a and the third conductor portion 10c, and has a shape bent upward.

[Production method of current sensor]
Next, a method for manufacturing the current sensor 1 will be described with reference to FIGS. FIG. 5 is a diagram illustrating an example of a method for manufacturing the current sensor 1.

  FIG. 5 shows an example in which the current sensor 1 is manufactured in the order from (A) to (G) as an example of a process for manufacturing the current sensor 1. 5A to 5G are a top view as viewed from above, and a right side is a cross-sectional view or side view as viewed from the side. In the cross-sectional view or the side view, the corresponding cross-section or side portion (A-A ′, etc.) is shown on the right side of FIG.

  FIG. 5A shows a lead frame forming process. In this step, a region (gap) 23 in which the magnetoelectric conversion elements 13a and 13b are disposed is formed by punching or etching the lead frame 100, and the conductor 10 having a predetermined shape in plan view is formed. Further, a wide portion of the lead frame 100 corresponding to the fixing portion 30 and a wide portion to which the insulating sheet is attached are also formed.

  Further, a portion to be the signal terminal 41 is also formed during this process. In FIG. 5A, signal terminals 41 are formed on both sides of the package in a direction perpendicular to the measured current terminals 12a and 12b which are input / output terminals.

  FIG. 5B shows a lead frame bending process. In this step, the lead frame is bent, and the second conductor portion 10b is bent upward to be formed above the first conductor portion 10a and the third conductor portion 10c via the step 31. Further, by bending the wide portion of the lead frame 100 upward, the fixing portions 30 are formed on both sides of the lead frame 100 so as to be separated from the conductor 10 via the step 31.

  In addition to the bending process, the second conductor part 10b may be formed above the first conductor part 10a and the third conductor part 10c via the step 31 by crushing.

  FIG. 5C shows an insulating sheet forming step. In this step, for example, an insulating tape is attached to the lower surface of the lead frame 100 as the insulating sheet 14. By attaching the insulating sheet 14 to the back surface of the wide portion of the lead frame formed in the aforementioned step (A), an insulating sheet 14 for mounting a magnetoelectric conversion element to be described below is provided below the second conductor portion. Fixed.

  FIG. 5D shows a die bonding process. In this step, the magnetoelectric conversion elements 13a and 13b are fixed on the insulating tape as the insulating sheet 14 by die bonding via, for example, a die attach film as an insulating material.

  Further, the signal processing IC 20 is fixed by the fixing portion 30 above the first conductor portion 10a by die bonding. In this case, an insulating sheet can be pasted on the fixing portion 30 or an insulating paste can be applied.

  In order to improve insulation, an insulating member such as an insulating tape may be disposed on the first conductor portion 10a.

  FIG. 5E shows a wire bonding process. In this step, the lead frame 100 on the signal terminal 41 side and the signal processing IC 20 are connected by the wire 50 by wire bonding. Further, the magnetoelectric conversion elements 13a and 13b and the signal processing IC 20 are connected by wires 60a and 60b by wire bonding.

  FIG. 5F shows a molding process. In this step, the conductor 10, the magnetoelectric conversion elements 13a and 13b, the signal processing IC 20, and the wires 50, 60a, and 60b are sealed and covered with the molding resin 80 by molding.

  FIG. 5G shows the lead forming process. In this step, lead current forming, that is, the current terminals 12a and 12b to be measured and the signal terminals 41 are formed by bending after cutting the lead terminals, whereby the package of the current sensor 1 is completed.

  As described above, according to the current sensor 1 of the present embodiment, by providing the above-described step 31 on the conductor 10 and the lead frame 100, the magnetoelectric transducer 13a, A gap of a predetermined distance can be provided between 13b and the second conductor portion 10b.

  A gap of a predetermined distance can be provided between the signal processing IC 20 and the first conductor portion 10 by the step 31 of the present embodiment.

  Thereby, the withstand voltage of the current sensor 1 can be improved.

  In particular, a desired insulation performance according to the distance between the signal processing IC 20 and the conductor 10 is appropriately adjusted by the step 31 by appropriately adjusting the distance of the gap between the signal processing IC 20 and the conductor 10 through which the current to be measured flows. Can be realized.

  Further, since a gap is formed between the signal processing IC 20 and the conductor 10 so that creepage between the signal processing IC 20 and the conductor 10 cannot be performed, for example, the present embodiment is implemented rather than an insulation method in which an insulating sheet is mounted on the conductor 10. The withstand voltage of the current sensor 1 of the embodiment is improved. Further, the presence of the step 31 can eliminate the creeping surfaces of the magnetoelectric conversion elements 13a and 13b and the conductor 10, so that the withstand voltage of the current sensor 1 is improved.

  Furthermore, in the current sensor 1 of the present embodiment, the signal processing IC 20 is disposed above the conductor 10, so that the package can be reduced in size.

<Embodiment 2>
Hereinafter, a second embodiment of the current sensor of the present invention will be described.

  The current sensor of the present embodiment is different from that of the first embodiment in the shape of the second conductor portion 10b described above and the fixing portion 30 described above.

  The second conductor portion of the present embodiment is different from the shape of the second conductor portion 10b described above in plan view.

[Configuration of current sensor]
The configuration of the current sensor of this embodiment will be described with reference to FIGS. FIG. 6 is a diagram illustrating an example of the internal structure of the current sensor 1A according to the present embodiment. 7A and 7B are diagrams showing an example of a cross section inside the current sensor, where FIG. 7A is a cross section taken along the line EE ′ shown in FIG. 6, FIG. 7B is a cross section taken along the line FF ′ shown in FIG. ) Shows the GG ′ cross section shown in FIG. 6, and (d) shows the HH ′ cross section shown in FIG. 6.

  The second conductor portion 10b of FIG. 6 has a first bent portion 111 surrounding the first magnetoelectric conversion element 13a and a second bent portion 112 surrounding the second magnetoelectric conversion element 13b in plan view. The second conductor portion 10b of the present embodiment is, for example, S-shaped (or Z-shaped).

  In the conductor 10 of FIG. 6 as well, as shown in the first embodiment, the second conductor portion 10b has a step 31 from the first conductor portion 10a, as shown in the cross-sectional views of FIGS. The third conductor portion 10 c is formed downward from the second conductor portion 10 b via the step 31. As shown in FIG. 7 (d), the second conductor portion 10b is located above the first conductor portion 10a and the third conductor portion 10c and has a shape bent in the vertical direction.

  The first bent portion 111 is not limited to the form shown in FIG. 6, and may be configured to surround the first magnetoelectric transducer 13 a with at least two straight lines (including three straight lines) in plan view. . The second bent portion 112 may be configured to surround the second magnetoelectric conversion element 13b with at least two straight lines (including three straight lines).

  In the present embodiment, the bent portion means that the path of the current to be measured flowing through the conductor 10 is bent in plan view. The bent portion includes not only a form surrounding the magnetoelectric conversion element on the same plane, but also a form surrounding the magnetoelectric conversion element in a plan view even if not on the same plane. That is, the bent portion has no relation to the cross-sectional direction of the current sensor 1A, and means that the bent portion surrounds the magnetoelectric conversion element in plan view.

  The bent portion will be further described. The bent portion corresponds to a portion in which the direction of the current flowing in the measured current path changes. A form in which the first magnetoelectric transducer 13a is surrounded by a straight line with two sides (that is, a form in which the direction of current flow changes from one direction to another direction), or a form in which the first magnetoelectric conversion element 13a is surrounded by a straight line with three sides (ie, the direction in which the current flows) A form that changes from one direction to another and further changes direction, a form that is surrounded by a curve (that is, a form in which the direction of current flow changes continuously from one direction), and a combination of a straight line and a curve Also includes form.

  In the present embodiment, the S-shape is a shape that is a straight line, a curve, or a combination thereof, and is an S-shape or a shape obtained by horizontally inverting the S-shape. Further, the Z-shape is a shape formed by a straight line, a curve, or a combination thereof, and is a shape obtained by horizontally inverting the Z-shape or the Z-shape.

  Further, unlike the fixing unit 30 shown in the first embodiment, the fixing unit 30a in FIG. 6 is not a mode in which the signal processing IC chip is supported from both sides by a fixing unit consisting of one wide portion, but a plurality of fixing units. In this configuration, the signal processing IC chip is supported from both sides. The shape of the fixed part and the number of fixed parts in plan view are not particularly limited.

  Even if it is configured as the current sensor 1A of the present embodiment, the same effect as in the first embodiment can be obtained, and the current path before the bending of each magnetoelectric conversion element 13a, 13b is bent by the second conductor portion 10b. Since the magnetic flux generated by adding the magnetic flux generated by the flowing current and the magnetic flux generated by the current flowing through the bent current path can be output, the sensitivity is improved.

<Embodiment 3>
Next, a current sensor 1B according to Embodiment 3 will be described with reference to FIGS. The present embodiment is different from the first embodiment in the shape or arrangement of the lead frame and the signal terminal, and will be described below mainly.

  FIG. 8 is a diagram showing an example of the internal structure of the current sensor 1B according to the present embodiment. 9 is a diagram illustrating an example of a cross section inside the current sensor 1B, where (a) is a cross section taken along the line II ′ shown in FIG. 8, (b) is a cross section taken along the line JJ ′ shown in FIG. c) shows the KK ′ cross section shown in FIG. FIG. 10 is a diagram illustrating an example of the package appearance of the current sensor 1B.

  Unlike the one shown in FIG. 1, the current sensor 1B shown in FIG. 8 has a signal terminal 41 arranged on one side of the package (on the right side in FIG. 8), and the current terminals 12a and 12b to be measured are located on the upper side of the package. Alternatively, they are arranged on the left side of the lower side surface (on the left side in FIG. 8).

  The conductor 10 connected to the measured current terminals 12a and 12b is formed such that the measured current flows from one side of the package to the opposite side (FIG. 8).

  In FIG. 9A, the signal processing IC 20 is arranged above the first conductor portion 10a across the first conductor portion 10a by the fixing portion 30. In the example of FIGS. 9A and 9C, for example, a die attach film is attached as the adhesive 60 to the lower surface of the signal processing IC 20.

  In FIG. 9B, the signal processing IC 20 is arranged above the first conductor portion 10a, similar to that shown in FIG. Since they are separated from each other, the withstand voltage is improved.

  As shown in FIG. 1, the magnetoelectric transducers 13a and 13b are arranged on both sides of the second conductor portion 10b with the second conductor portion 10b interposed therebetween, as shown in FIG. And it is mounted on the insulating sheet supported by the lead frame which has the signal terminal arrange | positioned on the right side of a package, and the lead frame which does not have the signal terminal arrange | positioned on the left side of the package.

  Also in the current sensor 1B, as shown in FIGS. 4 (a) and 4 (b), as shown in FIGS. 10 (a) and 10 (b), it is sealed with a mold resin 80 such as an epoxy resin. Stopped and formed as the same package.

  The measured current terminals 12a and 12b and the signal terminal 41 are taken out from one side surface of the package. In the example of FIG. 10, the measured current terminals 12a and 12b and the signal terminal 41 are taken out from three side surfaces of the package.

  Even when configured like the current sensor 1B of the present embodiment, the same effects as those of the first embodiment can be obtained.

[Modification]
The current sensors 1, 1 </ b> A, 1 </ b> B of each embodiment described above are merely examples, and may be changed.

  The shape of the protrusion 16 of the first embodiment is not limited to the example illustrated in FIG. 1 and can be changed. For example, FIG. 11 illustrates the form of a protruding portion 16a that protrudes from the first conductor portion 10a toward the third conductor portion 10c so as to surround the region where the magnetoelectric conversion elements 13a and 13b are disposed. In FIG. 12, the form of the protrusion part 16b which protrudes toward the 1st conductor part 10a side from the 3rd conductor part 10c is illustrated so that the area | region where the magnetoelectric conversion elements 13a and 13b are arrange | positioned may be enclosed. The number of protrusions can be changed.

  For example, the height of the step 31 may be changed. Further, the step 31 between the second conductor portion 10b and the third conductor portion 10c may be smaller or larger than the step between the first conductor portion 10a and the second conductor portion 10b. It is good or equivalent.

  Further, the step 31 formed on the conductor 10 and the step formed on the lead frame 100 may be at different heights or the same.

  The step 31 may be provided at least between the first conductor portion 10a and the third conductor portion 10c, and no step is provided between the second conductor portion 10b and the third conductor portion 10c. You can also.

  Moreover, in each embodiment mentioned above, although the 1st conductor part 10a, the 2nd conductor part 10b, and the 3rd conductor part 10c were demonstrated, you may make it change the form of these conductor parts. For example, each conductor part 10a-10c is good also as a structure which has another conductor part in what was shown in each embodiment and the modification. Moreover, in the form of each conductor part, it is good also as a form which has another level | step difference from what was shown by each embodiment and modification.

  The step 31 may have a plurality of steps as well as a single step. Further, the step 31 is not limited to a step rising vertically, but may be a step formed with an inclination, or may be a step formed in a curved shape, or a combination of these shapes. .

  The fixed portions 30 and 30a may be a fixed portion composed of a wide portion, and the signal processing IC 20 may be supported from both sides, or the signal processing IC 20 may be supported by a plurality of fixed portions. It may be.

  The fixing portions 30 and 30a are not necessarily connected to the signal terminal 41, and a portion of the lead frame that is not externally connected as the signal terminal 41 is a fixing portion, and has a step with respect to the fixing portion. It may be a processed form.

  The central portion of the conductor 10 is the periphery of the conductor portion where the magnetoelectric conversion elements are arranged adjacent to each other. The measured current includes a measured current input terminal 12a, a measured current input portion that is a wide portion of the conductor 10, a center portion that is formed above with a step 31, and a measured current output that is a wide portion of the conductor 10. And the measured current output terminal 12b. Note that the current to be measured may be configured to flow in a direction opposite to the above-described direction. Specifically, it may be configured to flow from the measured current input terminal 12b toward the measured current output terminal 12a.

  For example, you may make it change the magnitude | size and shape of each conductor part 10a-10c according to the specification of a current sensor.

  The current sensors 1, 1A and 1B of the embodiments have been described by taking the semiconductor package as an example. However, the current sensors 1, 1A and 1B may have a module form including the above-described conductor, magnetoelectric conversion element, and signal processing IC on a substrate.

  Also, a magnetic material may be formed on the magnetosensitive surface of the magnetoelectric conversion element by, for example, magnetic plating. As a configuration example of the magnetic material, a magnetic chip such as ferrite may be used. Thereby, when the current I to be measured flows through the conductor 10, the magnetic flux generated by the current I to be measured is easily converged on the magnetic sensing part of the magnetoelectric transducer. Therefore, the current detection sensitivity of the current sensors 1, 1A, 1B is improved.

  Further, the current sensor can be implemented by combining the current sensors 1, 1A, 1B which have been individually described in the respective embodiments.

<Summary of this embodiment>
The current sensor according to the present embodiment is a package comprising a magnetoelectric conversion element that detects magnetic flux, a conductor through which a current to be measured flows, a signal processing IC that processes output from the magnetoelectric conversion element, and a lead frame that forms a signal terminal. It is the current sensor sealed in.

  The conductor has a first conductor portion and a second conductor portion formed with a step from the first conductor portion. The direction of the step is formed in the upper direction and in a direction not coming into contact with an insulating sheet to be described later, that is, a direction away from the insulating sheet.

  Further, the magnetoelectric conversion element is disposed on both sides of the second conductor portion on the insulating sheet supported by the lead frame. The insulating sheet is preferably supported on the lower surface of the lead frame, and the lower surface is the back side of the surface on which the signal processing IC is mounted.

  The signal processing IC is supported by a fixed portion in which a step of the lead frame is formed, and is disposed across the first conductor portion. The step is formed upward from the lead frame in a sectional view.

  In the present embodiment, since the magnetoelectric conversion elements are arranged on both sides of the conductor, the direction of the magnetic flux generated by the current to be measured has a reverse polarity. The disturbance magnetic field can be canceled by subtracting those signals having opposite polarities.

  In the present embodiment, since the conductor and the lead frame have steps, the distance between the magnetoelectric transducer and the second conductor portion can be provided in a cross-sectional view, and the signal processing IC is also a distance from the first conductor portion. The withstand voltage can be improved.

  In particular, the desired insulation performance according to the distance between the signal processing IC and the conductor can be realized by appropriately adjusting the distance between the signal processing IC and the conductor through which the current to be measured flows by the step. Moreover, since creepage of both can be eliminated at all, for example, the withstand voltage is improved as compared with an insulating method in which an insulating sheet is mounted on a conductor. Moreover, since there is a level difference, creepage between the magnetoelectric conversion element and the conductor can be eliminated, so that the withstand voltage is improved.

  Furthermore, since the signal processing IC is disposed above the conductor, the package can be reduced in size.

In the present embodiment, the “S-shape” is a shape formed by a straight line, a curve, or a combination thereof, and is an S-shape or a shape obtained by horizontally inverting the S-shape.
In the present embodiment, the “Z-shape” is a shape by a straight line, a curve, or a combination thereof, and is a Z-shape or a shape obtained by horizontally inverting the Z-shape.

1, 1A, 1BD Current sensor 10 Conductor 10a First conductor portion 10b Second conductor portion 10c Third conductor portion 12a, 12b Current terminal to be measured 13a, 13b Magnetoelectric conversion element 14 Insulating sheet 20 Signal processing IC
41 Signal terminal

Claims (15)

A plurality of magnetoelectric transducers for detecting magnetic flux;
A conductor through which the current to be measured flows;
A signal processing IC for processing the output from the magnetoelectric transducer;
A lead frame forming a signal terminal,
The conductor has a first conductor portion and a second conductor portion formed through a step from the first conductor portion,
Each of the magnetoelectric conversion elements is disposed on both sides of the second conductor portion on the insulating sheet supported by the lead frame with the second conductor portion interposed therebetween.
The signal processing IC is a current sensor that is supported by a fixing portion formed through a step from the lead frame and is disposed across the first conductor portion. A magnetoelectric transducer for detecting magnetic flux;
A conductor through which the current to be measured flows;
A signal processing IC for processing the output from the magnetoelectric transducer;
A lead frame forming a signal terminal,
The conductor has a first conductor portion and a second conductor portion formed above the first conductor portion through a step from the first conductor portion in a sectional view,
The magnetoelectric conversion element is disposed on both sides of the second conductor portion on the insulating sheet supported by the lower surface of the lead frame with the second conductor portion interposed therebetween.
The signal processing IC is a current sensor that is supported by a fixed portion formed in a cross-sectional view above the lead frame through a step, and is disposed across the first conductor portion.   The current sensor according to claim 1, wherein the conductor further includes a third conductor portion formed through a step from the second conductor portion. The first conductor portion and the third conductor portion are substantially on the same plane in a sectional view,
The current sensor according to claim 3, wherein the second conductor portion is formed above the first conductor portion and the third conductor portion through a step.   5. The signal processing IC is arranged so that both sides of the signal processing IC are supported by at least two fixing portions formed through a step from the lead frame and straddle over the first conductor portion. The current sensor according to any one of the above.   The current sensor according to any one of claims 1 to 5, wherein the insulating sheet is supported by a lower surface of the lead frame in a non-contact state with the second conductor portion.   The current sensor according to claim 3 or 4, wherein the second conductor portion is narrower than the first conductor portion and the third conductor portion.   The current sensor according to claim 1, wherein the second conductor portion has an I shape, an S shape, or a Z shape. A magnetoelectric transducer for detecting magnetic flux;
A conductor through which the current to be measured flows;
A signal processing IC for processing the output from the magnetoelectric transducer;
A lead frame forming a signal terminal,
The central portion of the conductor is formed above through a step in a cross-sectional view,
The magnetoelectric conversion element is disposed on both sides of the conductor portion on the insulating sheet supported by the lower surface of the lead frame with the central portion of the conductor interposed therebetween,
The signal processing IC is a current sensor that is supported by a fixing portion formed in a cross-sectional view above the lead frame through a step, and is disposed across the conductor other than the central portion.   The current sensor according to claim 9, wherein the insulating sheet is supported on a lower surface of the lead frame in a non-contact state with a central portion of the conductor. The magnetoelectric transducer, a package shape in which at least a part of the conductor and at least a part of the lead frame are sealed,
The current sensor according to any one of claims 1 to 10, further comprising a measured current input terminal and a measured current output terminal on opposite side surfaces of the current sensor.   The current sensor according to claim 11, further comprising signal terminals on opposite side surfaces of the current sensor in a direction orthogonal to the measured current input terminal and the measured current output terminal.   The current sensor according to claim 11, further comprising a signal terminal on a side surface on one side of the current sensor in a direction orthogonal to the measured current input terminal and the measured current output terminal. Forming a conductor through which a current to be measured flows and a lead frame having the shape of a signal terminal;
Bending or crushing the central part of the conductor, and bending upward in a sectional view;
Forming a fixed portion formed with a step above in a cross-sectional view by bending or crushing a part of the lead frame to be separated from the conductor and formed on both sides thereof;
A step of affixing an insulating sheet to the back surface of the other part of the lead frame, and fixing the insulating sheet to the lead frame in a direction below the central portion and across the central portion;
On the insulating sheet, a step of arranging magnetoelectric conversion elements on both sides across the central portion of the conductor;
Placing the signal processing IC on the fixed portion and placing the signal processing IC on the conductor other than the central portion; and
Electrically connecting the magnetoelectric conversion element and the signal processing IC, and the signal processing IC and a lead frame serving as the signal terminal with a conductive wire;
Sealing the magnetoelectric conversion element, the insulating sheet, the signal processing IC, at least a part of the lead frame, and at least a part of the conductor with a sealing resin;
A method for manufacturing a current sensor comprising:   The lead frame to be the signal terminal exposed from the sealing resin and the conductor exposed from the sealing resin are bent to form the signal terminal and the current input / output terminal to be measured. The manufacturing method of the current sensor of description.

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