JP2005121471A - Current sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact surface mounting current sensor in which magnetically sensitive surface of a magnetic sensor is accurately disposed so as to be perpendicular to a mount surface (in the magnetic flux direction) of the magnetic sensor. <P>SOLUTION: The current sensor is provided with a vertical type magnetic sensor 1 mounted on a first lead frame 3; a semiconductor integrated circuit 5 processing output signals from the vertical type magnetic sensor 1; a second lead frame 4 on which the vertical type magnetic sensor 1 and the semiconductor integrated circuit 5 are mounted; an electric conductor which electrically connects the vertical type magnetic sensor 1, the semiconductor integrated circuit 5 and the second lead frame 4; and a second resin 7 which seals the semiconductor integrated circuit 5, the second lead frame 4 and the electric conductor. The magnetically sensitive surface of the vertical type magnetic sensor 1 is disposed so as to be perpendicular to the mount surface of the second lead frame 4 on which the semiconductor integrated circuit 5 is mounted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a current sensor, and more particularly to a current sensor that measures a current amount by detecting a magnetic flux generated by a current to be measured by a magnetic sensor.

  In general, as a magnetic sensor, a Hall sensor using a Hall effect, a magnetoresistive element, or the like is known. Conventionally, a structure as shown in FIG. 6 is widely known as a current sensor using a magnetic sensor (see, for example, Patent Document 1).

  FIG. 6 is a block diagram for explaining a conventional current sensor. In the figure, reference numeral 11 denotes a magnetic sensor, 12 denotes a current path, 13 denotes an amplifier, and 14 denotes a magnetic material. This current sensor collects the magnetic flux generated by the current flowing through the current path 12 by the core made of the magnetic body 14, and the current is detected from the change in the magnetic flux detected by the magnetic sensor 11 disposed in the gap portion of the magnetic body 14. It is configured to measure the quantity.

  FIG. 7 is a block diagram for explaining a conventional surface-mount type current sensor, and the reference numerals in FIG. 7 are the same as those in FIG. This current sensor collects a magnetic flux generated by a current flowing through the current path 12 by a magnetic current collecting plate made of a magnetic material 14, and changes in the magnetic flux detected by the magnetic sensor 11 from a magnetic flux leakage from the magnetic current collecting plate. From this, the current amount is measured (see, for example, Patent Document 2).

JP-A-5-312839 US Pat. No. 5,942,895

  However, in the current sensor having the structure as described above, magnetic flux generated by current flowing through the current path is detected by using a magnetic material to collect the magnetic material, such as hysteresis and magnetic saturation. There is a problem of being affected by the characteristics of

  The present invention has been made in view of such problems. The object of the present invention is to use a vertical magnetic sensor and integrally mold it in a mold package together with a semiconductor integrated circuit. A small, surface-mountable current sensor that can be placed perpendicular to the mounting surface (magnetic flux direction) of the magnetic sensor with high accuracy without being affected by There is to do.

  The present invention has been made in order to achieve such an object, and the invention according to claim 1 is directed to placing a pellet having a magnetic sensing portion and an internal electrode, and mounting the pellet, A first lead frame to be connected to each other, a first resin that seals the pellet and a part of the first lead frame, and has a substantially rectangular parallelepiped shape and is electrically connected to the outside. A vertical magnetic sensor in which a connection surface of the first lead frame serving as a connecting terminal is exposed in contact with one side of the substantially rectangular parallelepiped, and the vertical magnetic sensor; A semiconductor integrated circuit for processing an output signal, the vertical magnetic sensor, a second lead frame for mounting the semiconductor integrated circuit, the vertical magnetic sensor, the semiconductor integrated circuit, and the second lead frame And electrically connect A magnetic sensitive surface of the vertical magnetic sensor, comprising: an electric body; the vertical magnetic sensor; the semiconductor integrated circuit; a second resin that seals a part of the second lead frame; Is arranged so as to be perpendicular to the mounting surface of the semiconductor integrated circuit of the second lead frame.

  The invention according to claim 2 is characterized in that, in the invention according to claim 1, the magnetic sensitive surface of the vertical magnetic sensor is arranged perpendicular to the magnetic flux lines generated by the current to be measured. To do.

  The invention according to claim 3 is the invention according to claim 1 or 2, characterized in that the vertical magnetic sensor is mounted on the semiconductor integrated circuit.

  The invention according to claim 4 is the invention according to claim 1, 2 or 3, wherein the vertical magnetic sensor is a Hall sensor utilizing the Hall effect.

  As the conductor for electrically connecting the electrode on the second lead frame or the semiconductor integrated circuit according to the present invention and the connection terminal of the vertical magnetic sensor, a thin metal wire such as gold or aluminum can be used. In order to arrange the magnetic sensitive surface perpendicularly to the direction of magnetic flux more easily and accurately, it is desirable to place the magnetic sensitive surface using an adhesive conductor such as solder or silver paste.

The first lead frame and the second lead frame are preferably made of a nonmagnetic material such as copper. Furthermore, it is desirable to use a nonmagnetic material such as silver or tin for the plating of the lead frame. Further, it is desirable that the external connection terminals of the second lead frame are extended in a direction perpendicular to the magnetic sensitive surface.
As the magnetic sensor, various magnetic sensors such as a Hall sensor using the Hall effect and a magnetoresistive element using the magnetoresistance effect can be applied, and an analog output type magnetic sensor is desirable.

  As described above, according to the present invention, the pellet having the magnetic sensing portion and the internal electrode, the first lead frame on which the pellet is placed and electrically connected to the internal electrode, the pellet and the first A first resin that seals a portion of the lead frame, the entire shape of which is a substantially rectangular parallelepiped, and the connection surface of the first lead frame that serves as a terminal for electrical connection to the outside is a substantially rectangular parallelepiped. A vertical magnetic sensor disposed adjacent to one side of one surface and exposed, a semiconductor integrated circuit for processing a signal output from the vertical magnetic sensor, and the vertical magnetic sensor and the semiconductor integrated circuit are mounted. A second lead frame to be placed, a conductor that electrically connects the vertical magnetic sensor, the semiconductor integrated circuit, and the second lead frame, one of the vertical magnetic sensor, the semiconductor integrated circuit, and the second lead frame. Part and conductor 2 and the magnetic sensing surface of the vertical magnetic sensor is arranged so as to be perpendicular to the mounting surface of the semiconductor integrated circuit of the second lead frame. A small, surface-mountable current sensor that can be accurately and perpendicularly arranged with respect to the mounting surface (magnetic flux direction) of the magnetic sensor without being affected can be realized. It becomes possible to respond conveniently to the application.

Embodiments of the present invention will be described below with reference to the drawings.
[Example 1]
1A and 1B are configuration diagrams for explaining a first embodiment of a current sensor according to the present invention. FIG. 1A is a top view and FIG. 1B is a side sectional view. In the figure, reference numeral 1 is a vertical magnetic sensor (Hall element), 2 is a magnetic sensitive surface, 3 is a first lead frame, 4 is a second lead frame, 5 is a semiconductor integrated circuit, and 6 is a first resin (mold). Resin) and 7 indicate the second resin (mold resin).

  The current sensor according to the first embodiment includes a vertical magnetic sensor 1 mounted on a first lead frame 3, a semiconductor integrated circuit 5 that processes an output signal from the vertical magnetic sensor 1, and a vertical magnetic sensor. A second lead frame 4 on which the sensor 1 and the semiconductor integrated circuit 5 are placed, and a conductor (not shown) that electrically connects the vertical magnetic sensor 1, the semiconductor integrated circuit 5 and the second lead frame 4. And a second resin 7 that seals the semiconductor integrated circuit 5, the second lead frame 4, and the conductor.

  In the vertical magnetic sensor 1, a pellet having a magnetic sensing part and an internal electrode is placed on the first lead frame 3, and the first lead frame 3 and the internal electrode are electrically connected, and the pellet and the first electrode are electrically connected. The first resin 6 is used to seal a part of one lead frame 3. The overall shape is a substantially rectangular parallelepiped, and the connection surface of the first lead frame 3 serving as a terminal for electrical connection to the outside is arranged in contact with one side of one surface of the rectangular parallelepiped.

  The magnetic sensitive surface of the vertical magnetic sensor 1 is arranged so as to be perpendicular to the mounting surface of the semiconductor integrated circuit 5 of the second lead frame 4. Preferably, it is desirable to arrange the magnetic sensitive surface of the vertical magnetic sensor perpendicular to the magnetic flux lines generated by the current to be measured.

  Further, the vertical magnetic sensor 1 may be placed on the semiconductor integrated circuit 5. The vertical magnetic sensor 1 is preferably a Hall sensor using the Hall effect.

  FIG. 5 is a graph showing the relationship between the measured current value and the output in the current sensor of Example 1 shown in FIG. 1, and it can be seen from FIG. 5 that good linearity is obtained.

  FIG. 2 is a diagram for explaining the relationship between the magnetic sensitive surface of the vertical magnetic sensor in the current sensor shown in FIG. 1 and the direction of the current to be measured. In FIG. 2, reference numeral 8 denotes a current path. Constituent elements having the same functions as those in FIG. By arranging the magnetic sensitive surface 2 of the vertical magnetic sensor 1 so as to be perpendicular to the magnetic flux lines indicated by the broken line arrows in the figure generated by the current to be measured flowing in the current path 8, the most efficient sensitivity can be obtained. It is configured to be obtained.

[Example 2]
FIGS. 3A and 3B are configuration diagrams for explaining a current sensor according to a second embodiment of the present invention. FIG. 3A is a top view and FIG. 3B is a side sectional view. Note that the reference numerals in the figure are the same as those in FIG. 1 differs from the first embodiment shown in FIG. 1 in that the vertical magnetic sensor 1 and the semiconductor integrated circuit 5 are arranged in series with respect to the magnetic flux direction. On the other hand, in the second embodiment, the vertical magnetic sensor 1 and the semiconductor integrated circuit 5 are arranged in parallel to the magnetic flux direction. In other words, the magnetic sensor 1 is disposed at a position rotated by 90 ° from the arrangement of FIG. 1 and the direction of the magnetic sensitive surface 2 is perpendicular to the magnetic flux lines as in the first embodiment. With the arrangement of the magnetic sensor 1, the arrangement relationship with the semiconductor integrated circuit 5 can be made different, and a current sensor according to the purpose of use of the magnetic sensor can be provided.

[Example 3]
4A and 4B are configuration diagrams for explaining a current sensor according to a third embodiment of the present invention. FIG. 4A is a top view and FIG. 4B is a side sectional view. Note that the reference numerals in the figure are the same as those in FIG. The third embodiment differs from the first embodiment shown in FIG. 1 in that the semiconductor integrated circuit 5 is placed on the second lead frame 4 and the magnetic sensor 1 is placed on the semiconductor integrated circuit 5. This is the point. With this arrangement, the mounting area on the second lead frame 4 can be reduced.

  With respect to a current sensor that measures the amount of current by detecting the magnetic flux generated by the current with a magnetic sensor, it is not necessary to use a magnetic material, so that it is not affected by the magnetic properties of the magnetic material, and the magnetic sensor is sensitive to magnetism. It is possible to provide a small-sized surface-mountable current sensor that can be accurately and vertically disposed on the surface (magnetic flux direction) of the magnetic sensor.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram for demonstrating Example 1 of the current sensor of this invention, (a) is a top view, (b) is side sectional drawing. It is a figure for demonstrating the relationship between the magnetic sensitive surface of the vertical magnetic sensor in the current sensor shown in FIG. 1, and the direction of to-be-measured current. It is a block diagram for demonstrating Example 2 of the current sensor of this invention, (a) is a top view, (b) is side sectional drawing. It is a block diagram for demonstrating Example 3 of the current sensor of this invention, (a) is a top view, (b) is side sectional drawing. It is the figure which showed the relationship between the to-be-measured current value and output in the current sensor of Example 1 shown in FIG. 1 in the graph. It is a block diagram for demonstrating the conventional current sensor. It is a block diagram for demonstrating the conventional surface mount type current sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic sensor 2 Magnetic sensitive surface 3 1st lead frame 4 2nd lead frame 5 Semiconductor integrated circuit 6 1st resin 7 2nd resin 8 Current path 11 Magnetic sensor 12 Current path 13 Amplifier 14 Magnetic body

Claims (4)

A pellet having a magnetic sensing part and an internal electrode, a first lead frame on which the pellet is placed and electrically connected to the internal electrode, and a part of the pellet and the first lead frame are sealed The first lead frame connecting surface of the first rectangular parallelepiped, which is a substantially rectangular parallelepiped and has an electrical connection terminal with the outside, is on one side of the substantially rectangular parallelepiped. A vertical magnetic sensor arranged in contact with and exposed;
A semiconductor integrated circuit for processing a signal output from the vertical magnetic sensor;
A second lead frame for mounting the vertical magnetic sensor and the semiconductor integrated circuit;
A conductor that electrically connects the vertical magnetic sensor, the semiconductor integrated circuit, and the second lead frame;
A second resin that seals the vertical magnetic sensor, the semiconductor integrated circuit, a part of the second lead frame, and the conductor;
A current sensor, wherein a magnetic sensitive surface of the vertical magnetic sensor is arranged so as to be perpendicular to a mounting surface of the semiconductor integrated circuit of the second lead frame.   The current sensor according to claim 1, wherein the magnetic sensitive surface of the vertical magnetic sensor is arranged perpendicular to the magnetic flux lines generated by the current to be measured.   The current sensor according to claim 1, wherein the vertical magnetic sensor is mounted on the semiconductor integrated circuit. The current sensor according to claim 1, wherein the vertical magnetic sensor is a Hall sensor using a Hall effect.

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