JP2017134022A - Electric current sensor and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve electric current detection accuracy.SOLUTION: An electric current sensor 100 comprises a first conductor including an electric current route 22 for flowing an electric current to be detected; a second conductor insulated from the first conductor and including a base 10 having an extending part 13 overlapping a curved part 22c of the electric current route 22 in a planar view; and a magnetic sensor 32 that detects a magnetic field generated by the electric current to be detected flowing in the electric current route 22. The magnetic sensor 32 is installed on the extending part 13 continuous with the base 10. With this configuration, heat generated by the magnetic sensor 32 is exhausted via the base 10, so that degradation in the magnetism detection accuracy of these sensors due to temperature change can be suppressed, and as a result high electric current detection accuracy can be maintained.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a current sensor and a manufacturing method.

A current sensor that detects the amount of current using a magnetic sensor is known. For example, in Patent Document 1, a primary conductor to which a current to be measured is input, a secondary conductor that supports a signal processing IC, and an insulating tape that is spanned between two protruding portions of the secondary conductor are supported. A current sensor having a magnetic sensor arranged in a gap of a primary conductor in a plan view is disclosed. When a current is input to the primary conductor, the current sensor detects a magnetic field generated around the primary conductor by the current using a magnetic sensor, and outputs an output signal corresponding to the amount of the current.
Patent Document 1 International Publication No. 2015/015539

  However, in the current sensor having the above-described configuration, the sensor is reduced in size by not using the magnetic convergence plate, and good magnetic convergence is obtained. On the other hand, the local temperature rise accompanying the downsizing causes the magnetic detection and the current detection. There is also concern about deterioration of accuracy.

  In the first aspect of the present invention, the first conductor for flowing the current to be measured, the second conductor insulated from the first conductor, having a portion overlapping the first conductor in plan view, and the current to be measured And a magnetic sensor for detecting the current sensor.

  In the second aspect of the present invention, the first conductor for flowing the measured current, the second conductor insulated from the first conductor and having a thickness different from the first conductor, and the measured current are detected. And a magnetic sensor for providing a current sensor.

  In a third aspect of the present invention, forming a first lead frame that includes a plurality of first conductors each incorporated in a separate current sensor and a plurality of second conductors each incorporated in a separate current sensor A step of forming a second lead frame including: a step of fitting a fitting portion for alignment provided on the first lead frame and the second lead frame and superimposing the first lead frame and the second lead frame Forming a plurality of packages each containing a plurality of first conductors and a plurality of second conductors in a state where the first lead frame and the second lead frame are overlaid, and a plurality of packages And a step of singulation.

  The summary of the invention does not enumerate all the features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

The internal structure of a current sensor is shown in plan view. The cross-sectional structure of the current sensor regarding the reference line BB in FIG. 1A is shown. An internal configuration of a current sensor including a current path provided with an extending portion is shown in a plan view. The structure of the first lead frame is shown in plan view. 3C shows a cross-sectional configuration of the first lead frame with respect to the reference line BB in FIG. 3A. The structure of the second lead frame is shown in plan view. 4B shows a cross-sectional configuration of the second lead frame with respect to the reference line BB in FIG. 4A. The 1st and 2nd lead frame overlaid by one step of the manufacturing process of an electric current sensor is shown in plane view. 5B shows a cross section of the superimposed first and second lead frames with respect to the reference line BB in FIG. 5A. The state of the current sensor formed by one step of the manufacturing process of the current sensor, that is, the superimposed first and second conductors are shown in plan view. FIG. 6B shows a cross section of the current sensor with respect to the reference line BB in FIG. 6A. A state of the current sensor formed by one step of the manufacturing process of the current sensor, that is, a state where the magnetic sensor is arranged is shown in a plan view. FIG. 7B shows a cross section of the current sensor with respect to the reference line BB in FIG. 7A. The state of the current sensor formed by one step of the manufacturing process of the current sensor, that is, the state where the signal processing IC is wire bonded to the magnetic sensor and the terminal is shown in plan view. 8C shows a cross section of the current sensor with respect to the reference line BB in FIG. 8A. A state of the current sensor formed by one step of the manufacturing process of the current sensor, that is, a packaged state is shown in a plan view. FIG. 9B shows a cross section of the current sensor with respect to the reference line BB in FIG. 9A. The internal structure of the current sensor which concerns on a modification is shown in planar view. FIG. 10B shows a cross-sectional configuration of a current sensor according to a modified example related to the reference line BB in FIG. 10A. The state of the current sensor according to the modification formed by one step of the manufacturing process of the current sensor, that is, the state where the magnetic sensor is arranged is shown in plan view. 11B shows a cross section of the current sensor with respect to the reference line BB in FIG. 11A. The state of the current sensor which concerns on the modification formed by one step of the manufacturing process of a current sensor, ie, the piled 1st and 2nd conductor is shown in planar view. 12C shows a cross section of the current sensor with respect to the reference line BB in FIG. 12A. The state of the current sensor according to the modification formed by one step of the manufacturing process of the current sensor, that is, the state where the signal processing IC is wire bonded to the terminal is shown in plan view. 13B shows a cross section of the current sensor with respect to the reference line BB in FIG. 13A. The state of the current sensor according to the modification formed by one step of the manufacturing process of the current sensor, that is, the packaged state is shown in a plan view. 14B shows a cross section of the current sensor with respect to the reference line BB in FIG. 14A.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  1A and 1B show the internal configuration of the current sensor 100 according to the present embodiment. Here, FIG. 1A shows the internal configuration of the current sensor 100 in plan view, and FIG. 1B shows the cross-sectional configuration of the current sensor 100 with respect to the reference line BB in FIG. 1A. Here, the vertical direction in FIG. 1A is the vertical direction, the horizontal direction in FIGS. 1A and 1B is the horizontal direction, and the vertical direction in FIG. 1B is the height direction. The current sensor 100 is a current sensor that detects the amount of current input to the current path using a magnetic sensor, and aims to improve current detection accuracy.

  The current sensor 100 includes a package 9, a base 10, a plurality of device terminals 17, a current path 22, a first magnetic sensor 32, a second magnetic sensor 33, a signal processing device 42, and a magnetic body 18. The first lead frame 20 is configured to include one or a plurality of first conductors forming the current path 22, and the base 10 on which the signal processing device 42 is mounted and a plurality of second conductors forming the one or more device terminals 17. Including the second lead frame 19 is configured.

  The package 9 seals each component of the current sensor 100 inside, except for two terminal terminals 15 and 16 of the base 10 to be described later, a plurality of device terminals 17, and each terminal portion of the current path 22. Then, the primary conductor including the current path 22 and the secondary conductor including the plurality of device terminals 17 are insulated and protected. The package 9 is molded using, for example, a resin having excellent insulating properties such as epoxy, so that the thickness is smaller than the length of the rectangular upper surface (that is, the front surface in FIG. 1A) and one side of the upper surface. It is formed into a rectangular parallelepiped shape. Note that one side of the package 9 (that is, the right side in FIGS. 1A and 1B) is the first side 9a, and another side that is opposite to the first side 9a (that is, the left side in FIGS. 1A and 1B) is the first side. Let it be two sides 9b.

  The base 10 supports the first magnetic sensor 32, the second magnetic sensor 33, and the signal processing device 42. The base 10 is formed into a plate shape using, for example, a metal having high thermal conductivity in order to dissipate heat generated by these. The base 10 includes a main body 11, extending portions 13a and 13b, and two sets of device terminals 15 and 16.

  The main body 11 is large enough to support the signal processing device 42 in plan view. The main body 11 has a trapezoidal notch 11a on one side in the lateral direction (that is, the left side in FIG. 1A), and is stretched into the notch 11a from the center of the one side toward the one side. A rectangular overhang 11b is formed. The main body 11 is arranged in the approximate center of the package 9 with its longitudinal direction in the vertical direction and the notch 11a and the overhang 11b facing the second side 9b.

  The extending portions 13a and 13b are formed to extend from the center of the other side in the short side direction of the main body 11 (that is, the right side in FIG. 1A) toward the other side while being separated in the vertical direction. . Each of the extending portions 13a and 13b has a portion that overlaps first and second magnetic sensors 32 and 33, which will be described later, in plan view, and supports the first and second magnetic sensors 32 and 33 thereon. The extending portions 13a and 13b have a minimum vertical width to support the first and second magnetic sensors 32 and 33, respectively. Thereby, the eddy current generated when the magnetic field enters the extending portions 13a and 13b is suppressed. In particular, the measured current applied to the first conductor forming the current path 22 is changed, and thus the eddy current is generated in the extending portions 13a and 13b. The eddy current is suppressed, and the deterioration of the response of the first and second magnetic sensors 32 and 33 due to the magnetic field in which the eddy current is generated can be avoided.

  The two sets of device terminals 15 and 16 are each from one end (that is, the upper end in FIG. 1A) and the other end (that is, the lower end in FIG. 1A) to the second side 9b. Extend. In the present embodiment, as an example, the two sets of device terminals 15 and 16 each include three terminals. The device terminals 15 and 16 are provided with a step in the height direction by step processing and lower the tip with respect to the base end, thereby forming the terminal portions 15a and 16a at the tip, respectively. Note that the terminal portions 15a and 16a are joined to a wiring or the like provided on the external substrate when the current sensor 100 is mounted on the external substrate, for example.

  A plurality of device terminals (also referred to as signal terminals) 17, together with the device terminals 15 and 16, output the detection result of the current output from the signal processing device 42 to an external device, and input / output terminals for setting correction parameters It is. In the present embodiment, the device terminal 17 is provided on the second side 9b side. The device terminal 17 is formed in a rectangular plate shape using a conductor such as metal.

  In the present embodiment, as an example, six device terminals 17 are arranged at equal intervals between the two sets of device terminals 15 and 16 of the base 10 with their longitudinal directions oriented in the horizontal direction. The six device terminals 17 are provided with a step in the height direction by step processing, and the tip (left end in the drawing) is lowered with respect to the base end (right end in the drawing), thereby forming a terminal portion 17a at the tip. Note that, when the current sensor 100 is mounted on, for example, an external substrate, the terminal portion 17a is bonded to a wiring or the like disposed on the external substrate.

  The current path 22 is a primary conductor through which a current (that is, a current to be measured) detected by the current sensor 100 is passed. In the present embodiment, the current path 22 is disposed on the first side 9a side. The current path 22 is formed in a U shape extending from the first current terminal 22a provided on the first side 9a side to the second current terminal 22e provided on the first side 9a side through the inside of the package 9. In the present embodiment, the current path 22 is formed using a conductor such as metal to a thickness different from that of the base 10, and here, thicker than the base 10 in order to pass a particularly large current to be measured.

  The current path 22 includes two current terminals (also simply referred to as terminal portions) 22a and 22e, two step portions 22b and 22d, and a curved portion 22c.

  The two terminal portions 22a and 22e have a rectangular shape with the uniaxial direction (that is, the vertical direction) as a longitudinal direction in plan view. The terminal portions 22a and 22e are formed by providing a step in the height direction by step processing and lowering the tip of the current path 22 with respect to step portions 22b and 22d, which will be described later.

  The two step portions 22b and 22d have a rectangular shape with a length in the vertical direction equal to the two terminal portions 22a and 22e, respectively, in plan view. In the terminal portions 22a and 22e, a plurality of (here, five as an example) rectangular openings are arranged in the vertical direction on one side (here, the right side) in a direction orthogonal to the uniaxial direction (that is, the horizontal direction). Is formed. The step portions 22b and 22d integrally connect the terminal portions 22a and 22e to a curved portion 22c described later.

  The curved portion 22c connects the two step portions 22b and 22d. The curved portion 22c extends leftward from the lower left end of the stepped portion 22b, extends in the right direction in a U shape, and is connected to the upper left end of the stepped portion 22d. Here, the width of the space formed inside the curved portion 22 c is larger than the width of the first magnetic sensor 32.

  Further, the curved portion 22c is raised with respect to the step portions 22b and 22d by providing a step in the height direction by the step processing. Thereby, the bottom surface of the curved portion 22 c is higher than the top surface of the extending portion 13 a of the base 10, and the curved portion 22 c of the current path 22 is separated from the base 10. That is, the first lead frame 20 has an extended portion of the base 10 from the terminal portions 15a and 16a of the device terminals 15 and 16 in the second lead frame 19 at a curved portion 22c surrounding the first magnetic sensor 32 as will be described later. A step is further processed above 13a.

  In the present embodiment, the curved portion 22c of the current path 22 is separated from the extending portion 13a of the base 10 by providing a step in the height direction by step processing and raising the curved portion 22c with respect to the step portions 22b and 22d. However, instead of this, the extending portion 13a is provided with a step in the height direction by step processing and lowered with respect to the main body 11, thereby separating the curved portion 22c of the current path 22 from the extending portion 13a of the base 10. May be.

  The current path 22 overlaps the bent portion 22c on the extending portion 13a of the base 10 in a plan view, but is insulated without overlapping in a side view, and is sealed in the package 9 by projecting the terminal portions 22a and 22e. . The terminal portions 22a and 22e of the current path 22 are joined to a wiring or the like disposed on the external substrate when the current sensor 100 is mounted on the external substrate, for example.

  The first magnetic sensor 32 detects a magnetic field generated by a current passed through the current path 22. As the first magnetic sensor 32, for example, a compound semiconductor Hall element composed of InAs, GaAs, etc., a Hall element composed of silicon (or a Hall IC integrated with an amplifier circuit), and a magnetoresistive element are employed. Can do.

  The first magnetic sensor 32 has a portion that overlaps with the extending portion 13a of the base 10, and is disposed on the inner side of the curved portion 22c surrounded by the current path 22 in plan view. Here, the magnetic sensing surface of the first magnetic sensor 32 (that is, the detection surface for detecting the magnetic field) is provided on the upper surface of the first magnetic sensor 32 in the present embodiment. The magnetic sensitive surface of the first magnetic sensor 32 is preferably disposed at the center height of the plate thickness of the current path 22 between the upper surface and the lower surface of the current path 22 in the height direction. Thereby, the magnetic field generated by the current flowing through the current path 22 can be detected to the maximum, and a high S / N ratio can be obtained.

  The first magnetic sensor 32 is connected to the signal processing device 42 by wire bonding, and outputs a voltage corresponding to the detected magnetic field strength to the signal processing device 42 as an output signal.

  The second magnetic sensor 33 is disposed outside the curved portion 22 c surrounded by the current path 22 in a plan view, and detects magnetic noise such as an external magnetic field generated around the current path 22 substantially equal to the first magnetic sensor 32. As the second magnetic sensor 33, an element similar to the first magnetic sensor 32 can be adopted. By calculating the difference between the output signal of the first magnetic sensor 32 and the output signal of the second magnetic sensor 33, the influence of an external magnetic field or the like can be canceled.

  The sensitivity of the first and second magnetic sensors 32 and 33 for detecting the magnetic field usually depends on the environmental temperature. Therefore, as shown in FIG. 2, the current path 22 is provided with an extended portion 22f extending from the curved portion 22c, and the second magnetic sensor 33 is disposed in a region surrounded by the extended portion 22f and the curved portion 22c. It is good to do. Here, the extended portion 22f is integrally formed from the same material as the curved portion 22c. The heat generated when the current is applied to the curved portion 22c is transmitted to the extending portion 22f, and the second magnetic sensor 33 is placed in a temperature environment close to that of the first magnetic sensor 32. As a result, the magnetic field detection sensitivity of the second magnetic sensor 33 is equal to that of the first magnetic sensor 32. Therefore, the second magnetic sensor 33 can detect magnetic noise in the same manner as the first magnetic sensor 32.

  Note that the second magnetic sensor 33 is disposed on the extending portion 13b, and the magnetosensitive surface thereof is preferably between the upper surface and the lower surface of the current path 22 with respect to the height direction, preferably the center height of the plate thickness of the current path 22. Arranged. Thereby, the magnetic field generated by the current flowing through the current path 22 can be detected to the maximum, and a high S / N ratio can be obtained.

  The second magnetic sensor 33 is connected to the signal processing device 42 by wire bonding, and outputs a voltage corresponding to the detected magnetic field strength to the signal processing device 42 as an output signal.

  The signal processing device 42 processes the output signals of the first and second magnetic sensors 32 and 33 to calculate the amount of current that is passed through the current path 22. The signal processing device 42 includes a memory, a sensitivity correction circuit, an offset correction circuit that corrects an output offset, an amplification circuit that amplifies output signals from the first magnetic sensor 32 and the second magnetic sensor 33, and the first magnetic sensor 32. At least one of a difference calculation circuit that calculates a difference between the output signal and the output signal from the second magnetic sensor 33 provided outside the current path 22, a temperature correction circuit that corrects the output according to temperature, and the like is incorporated. May be.

  In the present embodiment, the signal processing device 42 adopts a hybrid configuration as a device separate from the first magnetic sensor 32 and the second magnetic sensor 33. The signal processing device 42 is supported on the main body 11 of the base 10 connected to the extending portions 13a and 13b on which the first and second magnetic sensors 32 and 33 are supported, respectively. As a result, the heat generated by the first and second magnetic sensors 32 and 33 is exhausted through the base 10, so that a decrease in their magnetic detection accuracy due to a temperature change is suppressed, and the first and second magnetic sensors 32 and 33 and the signal processing device 42 are placed under the same temperature, so that the output signals of the first and second magnetic sensors 32 and 33 are accurately corrected according to the temperature by the temperature correction circuit of the signal processing device 42. It becomes possible to do.

  The signal processing device 42 is connected to the six device terminals 17 by wire bonding. As a result, the signal processing device 42 inputs and outputs the calculation result of the amount of current passed through the current path 22, further parameter settings, and the like via the six device terminals 17. Since the signal processing device 42 is clamped to the main body 11 of the base 10, the device terminals 15 and 16 can be used as ground terminals. Further, by setting the base 10 to the ground potential or the constant potential, the base 10 serves as an electrostatic shield that shields electrostatic noise coming from the bottom surface side of the package 9.

  The lengths of the wires connecting the first and second magnetic sensors 32 and 33 to the signal processing device 42 may be equalized. Thereby, the parasitic capacitance between the primary conductor and each wire is made uniform, and the deterioration of the response characteristics of the first and second magnetic sensors 32 and 33 can be avoided.

  The magnetic body 18 is a member formed by, for example, magnetic plating, and focuses a magnetic field so as to put a large amount of magnetic flux perpendicularly to the magnetic sensitive surfaces of the first and second magnetic sensors 32 and 33. The magnetic body 18 is individually laid on the extending portions 13a and 13b of the base 10 on which the first and second magnetic sensors 32 and 33 are disposed, respectively, and is provided between the extending portions 13a and 13b. The first and second magnetic sensors 32 and 33 are supported.

  The magnetic body 18 may be laid only on one of the extending portions 13a and 13b where the first and second magnetic sensors 32 and 33 are disposed, respectively. Further, the magnetic body 18 is not limited to being individually laid on the extending portions 13a and 13b, but may be integrally disposed across the gap between the extending portions 13a and 13b.

  The upper surfaces of the first and second magnetic sensors 32 and 33 and the signal processing device 42 may be electrostatically shielded using a nonmagnetic conductive material such as aluminum. Thereby, electrostatic noise coming from the upper surface side of the package 9 can be shielded. In the nonmagnetic conductive material, a plurality of slits may be provided in portions facing the top surfaces of the first and second magnetic sensors 32 and 33. The plurality of slits are, for example, a plurality of cutouts opened at the outer edges of the conductive film material, each of which is aligned in the vertical direction with the longitudinal direction being in the horizontal direction. Thereby, the eddy current generated when the magnetic field enters the conductive film material is suppressed, and deterioration of the response of the first and second magnetic sensors 32 and 33 due to the magnetic field in which the eddy current is generated can be avoided.

  The first conductor forming the current path 22 and the base 10 on which the signal processing device 42 is mounted and the second conductor forming the plurality of device terminals 17 are respectively the first and second lead frames 20 having different conductor patterns. 19.

  3A and 3B show the configuration of the first lead frame 20. Here, FIG. 3A shows the configuration of the first lead frame 20 in plan view, and FIG. 3B shows the cross-sectional configuration of the first lead frame 20 with respect to the reference line BB in FIG. 3A. The first lead frame 20 is a metal frame having a rectangular shape. The thickness of the first lead frame 20 is different from that of the second lead frame 19. In particular, in this embodiment, the thickness is larger than that of the second lead frame 19 in order to pass a large current through the current path 22. In the first lead frame 20, as an example, 84 elements D20 arranged in a matrix of length 7 and width 12 are each formed with a pattern of the first conductor forming the current path 22. Here, the pattern is formed on the terminal portions 22a and 22e of the current path 22 in a state where the curved portion 22c of the current path 22 is raised with respect to the stepped portions 22b and 22d by providing a step in the height direction by step processing. Corresponding portions are connected to the frame and included in the first lead frame 20.

  The first lead frame 20 includes a first fitting portion C20 at each of the four corners. The first fitting portion C20 is, for example, two rectangular cutouts formed in parallel from the outer edge of the first lead frame 20 toward the inside.

  4A and 4B show the configuration of the second lead frame 19. 4A shows the configuration of the second lead frame 19 in plan view, and FIG. 4B shows the cross-sectional configuration of the second lead frame 19 with respect to the reference line BB in FIG. 4A. The second lead frame 19 is a metal frame having a rectangular shape. As an example, the base 10 on which the signal processing device 42 is mounted on 84 elements D20 arranged in a matrix of length 7 and width 12 and a plurality of device terminals. Second conductor patterns 17 are formed. Here, in the state where the step processing is not performed, the second lead frame 19 is formed by connecting portions corresponding to the terminal portions 15a and 16a of the base 10 and the terminal portions 17a of the plurality of device terminals 17 to the frame. Contained within.

  The second lead frame 19 includes a second fitting portion C19 at each of the four corners. The 2nd fitting part C19 is a level | step difference formed by raising two rectangular area | regions paralleled from another part by level | step process as an example.

  By superimposing the first lead frame 20 on the second lead frame 19, the current path 22 of the first conductor included in the element D20 on the extended portion 13a of the base 10 of the second conductor included in the element D19 in plan view. The plurality of elements D19 can be overlapped with the corresponding elements of the plurality of elements D20, respectively. Here, the steps of the four second fitting portions C19 of the second lead frame 19 are fitted into the notches of the first fitting portion C20 of the first lead frame 20, respectively, and the first lead is placed on the second lead frame 19. By overlapping the frames 20, the respective elements D19 and D20 can be accurately aligned.

  Instead of the notches and the steps, through holes may be provided at a plurality of corresponding positions of the first and second lead frames 20, 19 as the first fitting portion C20 and the second fitting portion C19. . The first lead frame 20 is overlaid on the second lead frame 19, and the rod-shaped member is passed through each of the vertically overlapping through holes, whereby the plurality of elements D19 are accurately positioned on the corresponding elements of the plurality of elements D20. Can be combined.

  A method for manufacturing the current sensor 100 will be described.

  First, a single metal plate is pressed to form a first lead frame 20 (see FIGS. 3A and 3B) that includes a plurality of patterns of the first conductor that forms the current path 22. Here, a step is provided on the plurality of patterns of the first lead frame 20 to provide a step in the current path 22. Thereby, the front end portion of the pattern, that is, the curved portion 22c is raised in the height direction with respect to the frame and the portion connected thereto.

  Next, another metal plate is pressed to form the second lead frame 19 (FIG. 4A) including a plurality of second conductor patterns forming the base 10 on which the signal processing device 42 is mounted and the plurality of device terminals 17. And FIG. 4B). The second lead frame 19 may be thinner than the first lead frame 20.

  Next, in the second conductor pattern included in the second lead frame 19, the magnetic body 18 is laid on the extending portions 13 a and 13 b of the base 10 where the first and second magnetic sensors 32 and 33 are respectively disposed. . This step may be performed before the metal plate is pressed to form the second lead frame 19 described above.

  Next, as shown in FIGS. 5A and 5B, the first lead frame 20 is overlaid on the second lead frame 19. Here, the steps of the four second fitting portions C19 of the second lead frame 19 are fitted into the notches of the first fitting portion C20 of the first lead frame 20, respectively. Thereby, as shown in FIGS. 6A and 6B, the bent portions 22c of the current paths 22 of the plurality of first conductors included in the first lead frame 20 in the plan view are a plurality of portions included in the second lead frame 19. The second conductors are positioned on the extending portions 13a of the respective bases 10 except that the curved portions 22c are raised in the height direction by step processing, so that they are separated from each other without contacting the extending portions 13a in a side view. Then, they are stacked.

  Next, as shown in FIGS. 7A and 7B, the first magnetic sensor 32, the second magnetic sensor 33, and the signal processing device 42 are installed on the pattern. The first magnetic sensor 32 is disposed on the extending portion 13 a of the base 10 inside the curved portion 22 c surrounded by the current path 22. The second magnetic sensor 33 is disposed on the extending portion 13b. The signal processing device 42 is disposed on the main body 11 of the base 10.

  Next, as shown in FIGS. 8A and 8B, the first magnetic sensor 32 and the second magnetic sensor 33 are connected to the signal processing device 42 by wire bonding, and the signal processing device 42, the device terminal 17, and the main body 11 are connected. Connect.

  Next, as shown in FIGS. 9A and 9B, each pattern is divided into a frame of the first lead frame 20 and a portion connecting the current lead path 22 and the frame of the second lead frame 19, and the base 10 and Molding is performed leaving a portion connecting the plurality of device terminals 17. As a result, a plurality of packages 9 are formed, and the first magnetic sensor 32, the second magnetic sensor 33, the signal processing device 42, and the inner portions of the patterns of the first and second conductors in which these are installed are sealed. Stopped.

  Finally, the plurality of packages 9 are separated into pieces. Here, the pattern exposed from the plurality of packages 9, that is, the frame of the first lead frame 20 and a portion connecting the frame to the current path 22, the frame of the second lead frame 19, the base 10, and the plurality of device terminals 17. The part which connects and is cut | disconnected. After cutting, each of the first and second conductors is formed so that the right end of the current path 22 is lowered in the height direction to form the terminal portions 22a and 22e, and the base 10 and the plurality of device terminals 17 are formed. The left ends of the terminals are lowered in the height direction to form the terminal portions 15a, 16a and 17a. Thereby, the current sensor 100 is completed.

  10A and 10B show an internal configuration of a current sensor 110 according to a modification. Here, FIG. 10A shows the internal configuration of the current sensor 110 in plan view, and FIG. 10B shows the cross-sectional configuration of the current sensor 110 with respect to the reference line BB in FIG. 10A. The current sensor 110 includes a package 9, a base 10, a plurality of device terminals 17, a current path 22, a magnetic detection device 44, and three magnetic bodies 18a, 18b, and 18c. In the current sensor 110, instead of the first magnetic sensor 32 and the second magnetic sensor 33 in the current sensor 100 according to the previous embodiment and the signal processing device 42 configured to be a separate device for these, a magnetic field is respectively provided. A magnetic detection device 44 including first and second magnetic detection units 34 and 35 for detecting the signal and a signal processing circuit (not shown) for processing these output signals is used. Therefore, among the components of the current sensor 110, the same or corresponding parts as those of the current sensor 100 according to the previous embodiment are denoted by the same reference numerals and detailed description thereof is omitted.

  The base 10 is a member that supports the magnetic detection device 44, and includes a main body 11 and two sets of device terminals 15 and 16.

  The main body 11 is large enough to support the magnetic detection device 44 in plan view. The main body 11 has a trapezoidal notch 11a on one side in the lateral direction (that is, the left side in FIG. 10A), and is stretched into the notch 11a from the center of the one side toward the one side. A rectangular protrusion 11b is formed, and a rectangular protrusion 12c is formed that protrudes from the other side in the short-side direction (that is, the right side in FIG. 10A) toward the first side 9a. The main body 11 is arranged at substantially the center of the package 9 with its longitudinal direction oriented in the vertical direction, the notch 11a and the overhang 11b facing the second side 9b, and the overhang 12c facing the first side 9a.

  The main body 11 has a portion that faces the back surface of a magnetic detection device 44 described later and overlaps the first and second magnetic detection portions 34 and 35, and supports the magnetic detection device 44 on a region including this portion. To do. The main body 11 has a slit 11c in a portion overlapping each of the first and second magnetic detection units 34 and 35. The slit 11c is, for example, one notch provided in the main body 11 extending leftward from the right end of the overhang 12c. Thereby, the eddy current generated when the magnetic field enters the main body 11 is suppressed. In particular, the eddy current generated in the main body 11 due to the change of the measured current applied to the first conductor forming the current path 22 is suppressed. It is possible to avoid the deterioration of the response of the first and second magnetic detectors 34 and 35 due to the magnetic field in which the eddy current is generated.

  The current path 22 is a primary conductor through which a current (that is, a current to be measured) detected by the current sensor 110 is passed, and is made to have a thickness different from that of the base 10 by using a conductor such as metal. It is formed thicker than the base 10 in order to pass a current to be measured. The current path 22 includes two current terminals (also simply referred to as terminal portions) 22a and 22e, two step portions 22b and 22d, and a curved portion 22c. Similarly to the current path 22 in the current sensor 100 according to the previous embodiment, the curved portion 22c is raised with respect to the step portions 22b and 22d by providing a step in the height direction by step processing such as bending. It faces the upper surface of a later-described magnetic detection device 44 supported on 11 and is separated from the main body 11 of the base 10.

  In the plan view, the current path 22 overlaps the curved portion 22c on the right center portion including the overhang 12c of the base 10, but is insulated without overlapping in the side view, and protrudes from the terminal portions 22a and 22e into the package 9. Sealed.

  The magnetic detection device 44 is, for example, a monolithic integrated circuit in which first and second magnetic detection units 34 and 35 and a signal processing circuit (not shown) are formed on a common silicon substrate.

  The first magnetic detection unit 34 is provided on one side (that is, the right side in FIG. 10A) on the upper surface of the magnetic detection device 44, and is disposed inside the curved portion 22c surrounded by the current path 22 in a plan view. A magnetic field generated by a current supplied to the path 22 is detected. The second magnetic detection unit 35 is provided at the center of the upper surface of the magnetic detection device 44, and is disposed outside the curved portion 22c surrounded by the current path 22 in a plan view, so that a magnetic field such as an external magnetic field generated around the current path 22 is obtained. Noise is detected approximately equal to the first magnetic sensor 32. By calculating the difference between the output signals of the first and second magnetic detectors 34 and 35, the influence of the external magnetic field or the like can be canceled.

  A signal processing circuit (not shown) processes the output signals of the first and second magnetic detectors 34 and 35 to calculate the amount of current passed through the current path 22. The signal processing circuit includes a memory, a sensitivity correction circuit, an offset correction circuit that corrects an output offset, an amplification circuit that amplifies output signals from the first and second magnetic detection units 34 and 35, and first and second magnetic detection units. At least one of a difference calculation circuit that calculates the difference between the output signals 34 and 35 and a temperature correction circuit that corrects the output according to the temperature may be incorporated.

  In this modification, a magnetic detection device 44 in which the first and second magnetic detection units 34 and 35 for detecting a magnetic field and a signal processing circuit for processing these output signals are monolithically configured in the same device is employed. The magnetic detection device 44 is supported on the main body 11 of the base 10, so that the heat generated by the curved portion 22 c of the current path 22 spreads almost uniformly over the entire magnetic detection device 44, so that their magnetic properties due to temperature changes are increased. A decrease in detection accuracy is suppressed. Further, the first and second magnetic detectors 34 and 35 and the signal processing circuit are placed under a more equal temperature, so that the first and second magnetic detectors 34 according to the temperature by the temperature correction circuit of the signal processing circuit. , 35 can be accurately corrected.

  The magnetic detection device 44 is connected to the six device terminals 17 by wire bonding. Thereby, the magnetic detection device 44 inputs / outputs the calculation result of the amount of current passed through the current path 22, and further parameter settings and the like via the six device terminals 17. Since the magnetic detection device 44 is clamped to the main body 11 of the base 10, the device terminals 15 and 16 can be used as ground terminals. Further, by setting the base 10 to the ground potential or the constant potential, the base 10 serves as an electrostatic shield that shields electrostatic noise coming from the bottom surface side of the package 9.

  The magnetic bodies 18 a, 18 b, and 18 c are members formed by, for example, magnetic plating, and a magnetic field is focused to generate a large amount of magnetic flux in the first and second magnetic detection units 34 and 35 of the magnetic detection device 44. Put it perpendicular to the surface. The magnetic body 18a is laid in a region on the base 10 where the first and second magnetic detectors 34 and 35 are located, and the first and second magnetic detectors 34 are provided on the main body 11 of the base 10 with the magnetic member 18a interposed therebetween. , 35 are arranged. The magnetic body 18 b is individually laid on the upper surface of the magnetic detection device 44 and on the upper surfaces of the first and second magnetic detection units 34 and 35. A part of the magnetic body 18c is supported on the curved portion 22c of the current path 22 of the primary conductor, and is disposed so as to cover the upper portions of the first and second magnetic detection units 34 and 35, respectively.

  The magnetic body 18a may be individually laid only on the part on the main body 11 where one of the first and second magnetic detection units 34, 35 is located, or on the two parts on the main body 11 where each is located. Good. Further, the magnetic body 18b may be laid only on the upper surface of one of the first and second magnetic detectors 34 and 35. Further, the magnetic body 18c may be individually disposed only above or above one of the first and second magnetic detectors 34 and 35, respectively.

  Note that the upper surface of the magnetic detection device 44 may be electrostatically shielded using a nonmagnetic conductor such as aluminum. Thereby, electrostatic noise coming from the upper surface side of the package 9 can be shielded. In addition, in the nonmagnetic conductor, by providing a slit in a portion facing the upper surfaces of the first and second magnetic detectors 34 and 35, an eddy current generated by a change in the current flowing through the current path 22 is suppressed, As a result, it is possible to avoid the deterioration of the responses of the first and second magnetic detectors 34 and 35.

  The first conductor forming the current path 22, the base 10 on which the magnetic detection device 44 is mounted, and the second conductor forming the plurality of device terminals 17 are respectively the first and second lead frames 20 having different conductor patterns, 19. Their detailed configurations are the same as those of the first and second lead frames 20 and 19 described above.

  A method for manufacturing the current sensor 110 according to the modification will be described. However, detailed description of the same or corresponding steps as the method of manufacturing the current sensor 100 according to the previous embodiment is omitted.

  First, a single metal plate is pressed to form the first lead frame 20 including a plurality of patterns of the first conductor forming the current path 22. Here, a step is provided on the plurality of patterns of the first lead frame 20 to provide a step in the current path 22. Thereby, the front end portion of the pattern, that is, the curved portion 22c is raised in the height direction with respect to the frame and the portion connected thereto.

  Next, another metal plate is pressed to form the base 10 on which the magnetic detection device 44 is mounted and the second lead frame 19 including a plurality of patterns of second conductors forming the plurality of device terminals 17. .

  Next, as shown in FIGS. 11A and 11B, in the second conductor pattern included in the second lead frame 19, the magnetic body 18 a is placed on the base 10 where the first and second magnetic detectors 34 and 35 are located. Lay in the area. This step may be performed before the metal plate is pressed to form the second lead frame 19 described above.

  Next, the magnetic detection device 44 is placed on the pattern. The first and second magnetic detection units 34 and 35 of the magnetic detection device 44 are arranged on the slit 11c provided in the main body 11, respectively. Further, the magnetic body 18 b is individually laid on the upper surfaces of the first and second magnetic detection units 34 and 35 of the magnetic detection device 44. This step may be performed prior to manufacturing the current sensor 110.

  Next, the first lead frame 20 is overlaid on the second lead frame 19. Accordingly, as shown in FIGS. 12A and 12B, the bent portions 22c of the current paths 22 of the plurality of first conductors included in the first lead frame 20 in the plan view are a plurality of portions included in the second lead frame 19. Alignment is made on the right center portion including the overhang 12c of the base 10 of each of the second conductors, but the curved portion 22c is raised in the height direction by step processing, so that it contacts the main body 11 in a side view. They are stacked without being spaced apart. At the same time, the first and second magnetic detection units 34 and 35 of the magnetic detection device 44 are positioned inside and outside the curved portion 22c surrounded by the current path 22, respectively, in plan view.

  Further, the magnetic body 18c is disposed so as to support a part of the curved portion 22c of the current path 22 of the primary conductor so as to cover the upper portions of the first and second magnetic detection units 34 and 35, respectively.

  Next, as shown in FIGS. 13A and 13B, the magnetic detection device 44, the device terminal 17, and the main body 11 are connected by wire bonding.

  Next, as shown in FIGS. 14A and 14B, the respective patterns are divided into the frame of the first lead frame 20 and the portion connecting the current path 22 and the frame of the second lead frame 19 and the base 10 and Molding is performed leaving a portion connecting the plurality of device terminals 17. Thereby, the plurality of packages 9 are formed, and the magnetic detection device 44 and the inner portions of the patterns of the first and second conductors on which the magnetic detection device 44 is installed are sealed.

  Finally, the plurality of packages 9 are separated into pieces. Here, the pattern exposed from the plurality of packages 9, that is, the frame of the first lead frame 20 and a portion connecting the frame to the current path 22, the frame of the second lead frame 19, the base 10, and the plurality of device terminals 17. The part which connects and is cut | disconnected. After cutting, each of the first and second conductors is formed so that the right end of the current path 22 is lowered in the height direction to form the terminal portions 22a and 22e, and the base 10 and the plurality of device terminals 17 are formed. The left ends of the terminals are lowered in the height direction to form the terminal portions 15a, 16a and 17a. Thereby, the current sensor 110 is completed.

  In the current sensor 100 according to the present embodiment and the current sensor 110 according to the modification, the current flowing through the channel current path 22 may be direct current or alternating current. In the case of direct current, the direction of the energized current may be arbitrarily determined.

  In the current sensor 100 of the present embodiment and the current sensor 110 according to the modification, a step is provided in the height direction in the current path 22 by step processing. Here, as step processing, for example, half blanking, forming, etching, coining, or the like can be used.

  In the current sensor 100 according to the present embodiment and the current sensor 110 according to the modification, the current to be measured is calculated based on the difference between the magnetic detection results using the two magnetic sensors 32 and 33 or the two magnetic detection units 34 and 35. However, the present invention is not limited to this, and a configuration in which the current to be measured is detected from the result of the magnetic detection using one magnetic sensor or one magnetic detection unit may be used. Even in such a configuration, it is possible to realize a highly accurate current sensor by placing the magnetic sensor and the signal processing device or the magnetic detection unit and the signal processing circuit under equal temperatures. In the current sensor 100, when only one magnetic sensor is used, the magnetic sensor is disposed on the extending portion 13a.

  In the current sensor 100 of the present embodiment and the current sensor 110 according to the modification, the package 9 includes the terminal portions 15a, 16a, and 17a of the plurality of device terminals 15, 16, and 17, and the terminal portions of the current path 22 (first portion). And the second current terminal) 22a and 22e are formed as a package having a lead. Alternatively, a leadless package having no lead may be formed.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

  The execution order of each process such as operation, procedure, step, and stage in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the specification, and the drawings, even if it is described using “first”, “next”, etc. for the sake of convenience, it means that it is essential to carry out in this order. It is not a thing.

  DESCRIPTION OF SYMBOLS 9 ... Package, 9a ... 1st edge, 9b ... 2nd edge, 10 ... Base, 11 ... Main body, 11a ... Notch, 11b ... Overhang, 11c ... Slit, 12c ... Overhang, 13a, 13b ... Extension part, 15, DESCRIPTION OF SYMBOLS 16, 17 ... Device terminal, 15a, 16a, 17a ... Terminal part, 18, 18a, 18b, 18c ... Magnetic body, 19 ... 2nd lead frame, 20 ... 1st lead frame, 22 ... Current path, 22a ... 1st Current terminal (terminal portion), 22b ... step portion, 22c ... curved portion, 22d ... step portion, 22e ... second current terminal (terminal portion), 32 ... first magnetic sensor, 33 ... second magnetic sensor, 34 ... first DESCRIPTION OF SYMBOLS 1 Magnetic detection part, 35 ... 2nd magnetic detection part, 42 ... Signal processing device, 44 ... Magnetic detection device, 100,110 ... Current sensor, C19 ... 2nd fitting part, C20 ... 1st fitting part, D19, D20 ... required .

Claims (19)

A first conductor for passing a current to be measured;
A second conductor insulated from the first conductor, having a portion overlapping the first conductor in plan view;
A magnetic sensor for detecting the measured current;
A package containing at least a part of the first conductor and the second conductor and the magnetic sensor;
A current sensor comprising:   The current sensor according to claim 1, wherein the overlapping portion of the second conductor is separated from the first conductor in a side view. A first conductor for passing a current to be measured;
A second conductor having a thickness different from that of the first conductor, insulated from the first conductor;
A magnetic sensor for detecting the measured current;
A package containing at least a part of the first conductor and the second conductor and the magnetic sensor;
A current sensor comprising:   The current sensor according to claim 3, wherein the first conductor is thicker than the second conductor.   5. The current sensor according to claim 1, wherein the first conductor and the second conductor are configured by two metal frames having conductor patterns different from each other. A signal processing device that has a portion overlapping the second conductor in plan view and that processes a signal from the magnetic sensor;
The first conductor forms a current path that returns from the first side of the package to the first side through the inside of the package;
The magnetic sensor is provided at a position where a part of the periphery is surrounded by the current path,
The current sensor according to claim 5, wherein the second conductor has a signal terminal provided on a second side opposite to the first side in the package and electrically connected to the signal processing device.   The current sensor according to claim 1, wherein the magnetic sensor has a portion overlapping the second conductor in plan view.   The current sensor according to claim 7, wherein the second conductor has an extending portion that extends to a portion overlapping the magnetic sensor in plan view. A device comprising a signal processing circuit for processing a signal from the magnetic sensor and the magnetic sensor;
The first conductor has a portion facing the first surface of the device;
The current sensor according to claim 1, wherein the second conductor has a portion facing a second surface opposite to the first surface of the device.   The current sensor according to any one of claims 1 to 9, wherein at least one of the first conductor and the second conductor is separated from the other conductor by a step.   11. The current sensor according to claim 1, wherein the second conductor has a portion overlapping the magnetic sensor in a plan view, and has a slit in the portion. The second conductor has a portion overlapping the magnetic sensor in plan view,
The current sensor according to claim 1, further comprising a first magnetic body provided between the magnetic sensor and the second conductor.   The current sensor according to any one of claims 1 to 12, further comprising a second magnetic body provided at a position facing a surface opposite to the second conductor side in the magnetic sensor. The first conductor forms a current path that returns from the first side of the package to the first side through the inside of the package;
The first magnetic sensor provided at a position surrounded by a part of the periphery of the current path;
A second magnetic sensor provided outside a region surrounded by the current path;
The current sensor according to claim 1, comprising:   The current sensor according to claim 14, further comprising a first magnetic body provided between the first magnetic sensor, the second magnetic sensor, and the second conductor.   Provided between a position facing the surface opposite to the second conductor side of the first magnetic sensor and a position facing the surface opposite to the second conductor side of the second magnetic sensor. The current sensor according to claim 14, further comprising a second magnetic body. Forming a first lead frame including a plurality of first conductors;
Forming a second lead frame including a plurality of second conductors and having a plurality of magnetic sensors disposed on the plurality of second conductors;
Superposing the first lead frame and the second lead frame;
Forming a plurality of packages by resin sealing in a state where the first lead frame and the second lead frame are overlapped;
Dividing the plurality of packages into pieces,
A method for manufacturing a current sensor comprising:   Each of these 2nd conductors is a manufacturing method of Claim 17 which has a part which overlaps with a corresponding 1st conductor in planar view among these 1st conductors.   The manufacturing method according to claim 18, wherein the first lead frame and the second lead frame have different thicknesses.