Electric current sensor

Abstract

This current sensor comprises: a first lead frame that includes a first terminal part and a first conductor part; a second lead frame that includes a second terminal part and a second conductor part, is thinner than the first lead frame, and is electrically insulated from the first lead frame; at least one magnetoelectric conversion element; and a signal processing IC. The first conductor part has a first portion facing the first surface of the signal processing IC, and a second portion that is connected to the first portion and is positioned closer to the second surface side of a sealing part than the first portion, thereby forming a first step portion together with the first portion, and that is connected to the first terminal part. When viewed from a direction from the first side surface to the second side surface of the sealing part, the second conductor part and the signal processing IC are positioned between a second surface of the first portion opposite to the first surface of the first portion facing the first surface of the sealing part and a second surface of the second portion opposite to the first surface of the second portion facing the first surface of the sealing part.

Description

Current Sensor

[0001] The present invention relates to a current sensor.

[0002] Patent Document 1 states that "In a circuit board 15 having lead frames 1 corresponding to a circuit pattern 3, a plurality of lead frames 1 are stacked to form a lead frame assembly 11 that serves as a conductive portion." Patent Document 2 states that "The lead frames having a wiring pattern shape have at least two or more different thicknesses, the thicker lead frames being used for large current signals, and the thinner lead frames being used for small current signals." [Prior art documents] [Patent documents] [Patent document 1] Japanese Patent No. 4419187 [Patent document 2] Japanese Patent No. 6179679 General disclosure

[0003] A current sensor according to one aspect of the present invention may include at least one magnetoelectric transducer. The current sensor may include a first lead frame including a first terminal and a first conductor, and a measurement current measured by the at least one magnetoelectric transducer flows through the first terminal and the first conductor. The current sensor may include a signal processing IC arranged on a second surface opposite to a first surface of the first conductor, having a circuit surface on which the at least one magnetoelectric transducer is arranged, and processing a signal output from the at least one magnetoelectric transducer. The current sensor may include a second lead frame that is thinner than the first lead frame and electrically insulated from the first lead frame, the second lead frame including a second terminal electrically connected to the signal processing IC and a second conductor supporting a second surface of the signal processing IC opposite to the first surface on the first conductor side. The current sensor may include a sealing portion that seals the at least one magnetoelectric transducer, at least a portion of the first conductor portion, the signal processing IC, and at least a portion of the second conductor portion. The sealing portion may have a first surface on the first surface side of the signal processing IC, a second surface of the sealing portion opposite the first surface, a first side surface from which the first terminal portion is exposed, and a second side surface opposite the first side surface from which the second terminal portion is exposed. The first conductor portion may have a first portion facing the first surface of the signal processing IC, and a second portion connected to the first portion and positioned closer to the second surface side of the sealing portion than the first portion to form a first step portion together with the first portion and connected to the first terminal portion. When viewed from the direction from the first side surface of the sealing portion toward the second side surface, the second conductor portion and the signal processing IC may be located between a second surface of the first portion opposite to a first surface of the first portion facing the first surface of the sealing portion, and a second surface of the second portion opposite to the first surface of the second portion facing the first surface of the sealing portion.

[0004] In the current sensor, the length in the thickness direction of the connection portion between the first portion and the second portion may be shorter than the length in the thickness direction of the first portion and the length in the thickness direction of the second portion.

[0005] In any one of the current sensors, a side surface extending from a connection portion of the second portion with the first portion to the second surface of the second portion may be along a thickness direction of the sealing portion.

[0006] In any of the current sensors, the angle formed between the side of the second part extending from the connection part with the first part to the second surface of the second part and the second surface of the first part may be approximately 90 degrees.

[0007] In any of the current sensors, the sum of the thickness of the second lead frame and the thickness of the signal processing IC may be smaller than the thickness of the first lead frame.

[0008] In any of the current sensors, the second conductor portion may have a third portion that supports the second surface of the signal processing IC, and a fourth portion that is connected to the third portion and is located closer to the second surface of the sealing portion than the third portion, thereby forming a second step portion together with the third portion, and is connected to the second terminal portion.

[0009] In any one of the current sensors, the second surface of the second portion and a second surface of the sealing portion of the fourth portion on the second surface side may be located on the same plane.

[0010] In any one of the current sensors, the second portion and the fourth portion may be exposed from the second surface of the sealing portion.

[0011] In any one of the current sensors, the second portion and the fourth portion may protrude from the second surface of the sealing portion.

[0012] In any of the current sensors, the distance between a plane including the second surface of the first terminal portion opposite the first surface of the first terminal portion on the first surface side of the sealing portion and the second surface of the second terminal portion opposite the first surface of the second terminal portion on the first surface side of the sealing portion may be 1 mm or more.

[0013] In any of the current sensors, the position of the surface of the sealing portion of the first lead frame on the first side surface of the sealing portion facing the second surface and the position of the surface of the sealing portion of the second lead frame on the second side surface of the sealing portion in the direction from the first surface of the sealing portion to the second surface of the sealing portion may be different.

[0014] In any of the current sensors, the first terminal portion may be a pair of lead terminals. The second portion may be a pair of second portions connected to the pair of lead terminals, respectively. The first portion may include a pair of first portions connected to the pair of second portions, respectively, and a connecting portion disposed between the pair of first portions and connected to the pair of first portions.

[0015] In any one of the current sensors, the at least one magnetoelectric conversion element may include a first Hall element and a second Hall element, and the first Hall element and the second Hall element may be arranged opposite each other across the connecting portion in a plan view.

[0016] In any one of the current sensors, the first Hall element may be disposed between the pair of first portions extending from the connecting portion toward the first terminal portion in a plan view.

[0017] In any one of the current sensors, the second Hall element may be disposed between the pair of first portions extending from the connecting portion toward the second terminal portion in a plan view.

[0018] In any of the current sensors, the pair of first portions may not be exposed to the outside of the sealing portion.

[0019] In any one of the current sensors, the first Hall element and the second Hall element may each be configured on a chip separate from a chip that configures the signal processing IC.

[0020] In any one of the current sensors, the first Hall element and the second Hall element may each be built into a chip that constitutes the signal processing IC.

[0021] In any of the current sensors, the at least one magnetoelectric transducer may include a first magnetoresistive element and a second magnetoresistive element. The first magnetoresistive element may be disposed opposite one of the pair of first portions. The second magnetoresistive element may be disposed opposite the other of the pair of first portions.

[0022] In any one of the current sensors, the first magnetoresistive element and the second magnetoresistive element may each be configured on a chip separate from a chip that configures the signal processing IC.

[0023] In any one of the current sensors, the first magnetoresistive element and the second magnetoresistive element may each be built into a chip that constitutes the signal processing IC.

[0024] In any of the current sensors, the distance between the second surface of the first portion and the magnetically sensitive surfaces of the first magnetoresistive element and the second magnetoresistive element may be 50 μm to 500 μm.

[0025] In any one of the current sensors, the first step portion and the second step portion may be located within the sealing portion.

[0026] In any one of the current sensors, at least one of the first step portion and the second step portion may be located outside the sealing portion.

[0027] In any one of the current sensors, the first lead frame may have a thickness of 1 mm or more.

[0028] In any of the current sensors, the second conductor portion may have a through slit with one side open that passes through a position opposite the at least one magnetoelectric conversion element in the thickness direction and extends to the outer peripheral end of the second conductor portion.

[0029] In any one of the current sensors, the second conductor portion may have an opening at a position facing the at least one magneto-electric transducer in a thickness direction.

[0030] In any of the current sensors, the sealing portion may include a third side surface and a fourth side surface that face each other in a direction intersecting a direction from the first terminal portion to the second terminal portion. The sealing portion may have a plurality of grooves on the first surface, the second surface, the third side surface, and the fourth side surface so as to surround the first surface, the second surface, the third side surface, and the fourth side surface.

[0031] In any one of the current sensors, the width of each of the plurality of grooves may be 1 mm or more.

[0032] In any one of the current sensors, the first terminal portion may have a through hole or a through slit with one side open for electrical connection to the substrate via a bolt.

[0033] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions.

[0034] 1A is a schematic plan view of the current sensor according to the first embodiment, as viewed from the ceiling surface side (positive side in the Z-axis direction). FIG. 1B is a cross-sectional view of the current sensor shown in FIG. 1A along line A-A. FIG. 1C is a schematic plan view of the current sensor according to the first embodiment, as viewed from the bottom surface side (negative side in the Z-axis direction). FIG. 1D is a schematic plan view of the current sensor according to the second embodiment, as viewed from the ceiling surface side (positive side in the Z-axis direction). FIG. 2A is a cross-sectional view of the current sensor shown in FIG. 2A along line A-A. FIG. 2D is a schematic plan view of the current sensor according to the third embodiment, as viewed from the ceiling surface side (positive side in the Z-axis direction). FIG. 3A is a cross-sectional view of the current sensor shown in FIG. 3A along line A-A. FIG. 4A is a schematic plan view of the current sensor according to the fourth embodiment, as viewed from the ceiling surface side (positive side in the Z-axis direction). FIG. 5A is a cross-sectional view of the current sensor shown in FIG. 5A along line A-A. FIG. 5D is a schematic plan view of the current sensor according to the fifth embodiment, as viewed from the bottom surface side (negative side in the Z-axis direction). 8A . FIG. 8B is a schematic plan view of the current sensor according to the fifth embodiment mounted on a substrate, as viewed from the ceiling surface side (Z-axis direction) of the current sensor. FIG. 8C is a schematic plan view of the current sensor according to the ninth embodiment mounted on a substrate, as viewed from the side (X-axis direction) of the current sensor. FIG. 8D is a schematic plan view of the current sensor according to the sixth embodiment, as viewed from the ceiling surface side (positive side in the Z-axis direction). FIG. 8E is a cross-sectional view of the current sensor shown in FIG. 7A . FIG. 8C is a schematic plan view of the current sensor according to the eighth embodiment, as viewed from the ceiling surface side (positive side in the Z-axis direction). FIG. 8E is a cross-sectional view of the current sensor shown in FIG. 8E . FIG. 8E is a plan view of another example of the second lead frame. FIG. 8F is a plan view of another example of the second lead frame. 11A is a schematic plan view of a current sensor according to a modified example, as viewed from the ceiling surface side (positive side in the Z-axis direction); FIG. 11B is a schematic plan view of the current sensor shown in FIG. 11A, as viewed from the bottom surface side (negative side in the X-axis direction); and FIG. 11C is a side view of a current sensor according to a modified example, as viewed from the negative side in the X-axis direction, mounted on a substrate.

[0035] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0036] In a small, one-package current sensor for large currents that incorporates a primary conductor through which a relatively large measurement current flows, the flow of the measurement current through the primary conductor generates heat, which may exceed the allowable operating temperature of the built-in electronic components depending on the temperature of the operating environment.In such cases, it becomes necessary to suppress the temperature rise by lowering the upper limit temperature of the operating environment or by using air cooling with a fan, water cooling with a pipe, or forced cooling with an electronic cooling device, etc.

[0037] On the other hand, even without using the above method, heat generation in the primary conductor can be suppressed by increasing the cross-sectional area of ​​the primary conductor, which is the heat source, thereby reducing its resistance. However, there are limitations to simply increasing the cross-sectional area of ​​the primary conductor, and it becomes difficult to miniaturize the current sensor. Therefore, it becomes impossible to miniaturize the application device using the current sensor, and if miniaturization of the application device cannot be achieved, the manufacturing cost of the application device increases. Furthermore, increasing the cross-sectional area of ​​the primary conductor also leads to a decrease in the sensitivity or deterioration of the frequency characteristics of the current sensor.

[0038] Therefore, in each embodiment, a configuration is provided in which a current sensor for detecting a relatively large current can be realized in a small package while suppressing an internal temperature rise.

[0039] 1A and 1B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to the first embodiment. Fig. 1A is a schematic plan view of the current sensor 10 according to the first embodiment as seen from the ceiling surface side (positive side in the Z-axis direction). Fig. 1B is a cross-sectional view of the current sensor 10 shown in Fig. 1A along line A-A. Fig. 1C is a schematic plan view of the current sensor 10 according to the first embodiment as seen from the bottom surface side (negative side in the Z-axis direction).

[0040] 1A, the coordinates are defined as the X-axis direction parallel to the paper surface and extending from bottom to top, the Y-axis direction parallel to the paper surface and extending from right to left, and the Z-axis direction perpendicular to the paper surface and extending from back to front. Any one of the X-axis, Y-axis, and Z-axis is orthogonal to the other axes.

[0041] The current sensor 10 may be a large-current coreless current sensor capable of measuring a relatively large current. The current sensor 10 includes a signal processing IC 100, a magnetoelectric conversion element 20 a, a magnetoelectric conversion element 20 b, a first lead frame 140 on the primary side, a second lead frame 150 on the secondary side, and a sealing portion 130.

[0042] The first lead frame 140 includes a first terminal 141 and a first conductor 142. The first terminal 141 and the first conductor 142 are physically integrated. A measurement current measured by the magnetoelectric conversion elements 20 a, 20 b flows through the first lead frame 140 via the first terminal 141 and the first conductor 142. The first terminal 141 may be a portion exposed from the sealing portion 130, and the first conductor 142 may be a portion built into the sealing portion 130 that is not exposed from the sealing portion 130. A portion of the first terminal 141 may be built into the sealing portion 130, or a portion of the first conductor 142 may be exposed from the sealing portion 130.

[0043] The second lead frame 150 includes a second terminal 151 and a second conductor 152. The second terminal 151 and at least a portion of the second conductor 152 are physically integrated. The second terminal 151 may be a portion exposed from the sealing portion 130, and the second conductor 152 may be a portion built into the sealing portion 130 that is not exposed from the sealing portion 130. A portion of the second terminal 151 may be built into the sealing portion 130, or a portion of the second conductor 152 may be exposed from the sealing portion 130. The second conductor 152 includes a plurality of lead terminals. Some of the plurality of lead terminals are physically integrated with the second conductor 152. The second terminal 151 is disposed opposite the first terminal 141 across the signal processing IC 100 in a plan view, and is electrically connected to the signal processing IC 100. The second terminal 151 is electrically connected to the signal processing IC 100 via a wire 108. The second conductor 152 supports the second surface 100b of the signal processing IC 100 opposite to the first surface 100a on the first conductor 142 side with a first surface 153a. The second lead frame 150 is thinner than the first lead frame 140 and is electrically insulated from the first lead frame 140. The thickness of the first lead frame 140 may be 1 mm or more.

[0044] The magnetoelectric conversion elements 20a and 20b are electrically connected to the signal processing IC 100 via wires 22a and 22b. In the first embodiment, the magnetoelectric conversion elements 20a and 20b are Hall elements. The magnetoelectric conversion elements 20a and 20b are made of a compound semiconductor material. The magnetoelectric conversion elements 20a and 20b may be made of a compound semiconductor formed on a GaAs substrate and may be chips cut into a square or rectangular shape when viewed from above in the Z-axis direction. The magnetoelectric conversion elements 20a and 20b are formed separately from the signal processing IC 100, which is made of a silicon monolithic material. The magnetoelectric conversion elements 20a and 20b output signals to the signal processing IC 100 to be processed by the signal processing IC 100. In the first embodiment, an example will be described in which the current sensor 10 includes two magnetoelectric conversion elements 20a and 20b. However, the current sensor 10 may include one or more magnetoelectric conversion elements.

[0045] The wires 22a, 22b and the wire 108 may be made of a conductive material containing Au, Ag, Cu, or Al as its main component.

[0046] The signal processing IC 100 is disposed on the surface opposite to the surface on the ceiling surface side of the first conductor portion 142. The signal processing IC 100 has a circuit surface on which magnetoelectric conversion elements 20a and 20b are disposed, and processes signals output from the magnetoelectric conversion elements 20a and 20b. The magnetoelectric conversion elements 20a and 20b are each formed on a chip separate from the chip that constitutes the signal processing IC 100. In the first embodiment, the circuit surface is the ceiling surface of the semiconductor package that constitutes the signal processing IC 100.

[0047] The signal processing IC 100 is a large-scale integrated circuit (LSI). The signal processing IC 100 is a signal processing circuit made of a Si monolithic semiconductor formed on a Si substrate. The signal processing circuit processes an output signal corresponding to the magnitude of the magnetic field output from the magnetoelectric conversion elements 20a and 20b. The signal processing circuit corrects the measurement current flowing through the first conductor 142 based on the output signal and outputs an accurate current value via the output signal terminal. The signal processing circuit cancels external magnetic noise based on the difference between the output signal of the magnetoelectric conversion element 20a and the output signal of the magnetoelectric conversion element 20b, performs absolute value correction and temperature correction of sensitivity and offset for calculating the current value of the measurement current, and finally outputs an amplified and accurate output signal indicating the current value.

[0048] The sealing section 130 is made of mold resin. The sealing section 130 seals the magnetoelectric conversion elements 20 a, 20 b, at least a portion of the first conductor section 142, the signal processing IC 100, and at least a portion of the second conductor section 152 with the mold resin. The mold resin may be made of, for example, an epoxy-based thermosetting resin with silica added thereto, and may be formed into a semiconductor package by transfer molding.

[0049] The sealing unit 130 has a first surface 130e which is a ceiling surface on the first surface 100a side of the signal processing IC 100, and a second surface 130f which is a bottom surface opposite the first surface 130e of the sealing unit 130. The sealing unit 130 has a first side surface 130a from which the first terminal unit 141 is exposed, and a second side surface 130b opposite the first side surface 130a from which the second terminal unit 151 is exposed. The sealing unit 130 has a third side surface 130c and a fourth side surface 130d which face each other in a direction along the X axis which is perpendicular to a direction along the Y axis from the first terminal unit 141 toward the second terminal unit 151 in a plan view.

[0050] The first conductor portion 142 has a first portion 143 facing the first surface 100a of the signal processing IC 100, and a second portion 144 connected to the first portion 143 and positioned closer to the second surface 130f, which is the bottom surface of the sealing portion 130, than the first portion 143, thereby forming a first step portion 145 together with the first portion 143, and connected to the first terminal portion 141.

[0051] The first step portion 145 may be formed between the first portion 143 and the second portion 144 by half-blanking. The first portion 143 protrudes toward the first surface 130e, which is the ceiling surface of the sealing portion 130, relative to the second portion 144. The distance between a plane including the second surface 141b of the first terminal portion 141 opposite to the first surface 141a of the first terminal portion 141 on the first surface 130e side of the sealing portion 130 and the second surface 151b of the second terminal portion 151 opposite to the first surface 151a of the second terminal portion 151 on the first surface 130e side of the sealing portion 130 and the second surface 130f of the sealing portion 130 may be 1 mm or more. As a result, when the current sensor 10 is mounted on a substrate, the substrate and the second surface 130f of the sealing portion 130 do not come into contact, ensuring insulation between the current sensor 10 and the substrate.

[0052] The first terminal 141 is a pair of lead terminals 141c. The second portion 144 is a pair of second portions 144c connected to the pair of lead terminals 141c, respectively. The first portion 143 includes a pair of first portions 146 connected to the pair of second portions 144c, respectively, and a connecting portion 147 disposed between the pair of first portions 146 and connected to the pair of first portions 146. In the first embodiment, the first terminal 141 and the first conductor 142 form a U-shape in plan view. The magnetoelectric transducers 20a, 20b are disposed opposite each other in the Y-axis direction, sandwiching the connecting portion 147, in plan view. The magnetoelectric transducer 20a is disposed inside the first lead frame 140, which is U-shaped in plan view. The magnetoelectric transducer 20a is disposed between the pair of first portions 146 extending toward the first terminal 141, in plan view. The magnetoelectric transducer 20b is disposed on the outside of the first lead frame 140 which has a U-shape.

[0053] The magnetically sensitive surfaces of the magnetoelectric conversion elements 20a and 20b are located inside the first portion 143 in a side view, i.e., when viewed from the X-axis direction. The magnetically sensitive surfaces of the magnetoelectric conversion elements 20a and 20b are located between the first surface 143a and the second surface 143b of the first portion 143 in a side view. As a result, a relatively large magnetic field is applied to the magnetically sensitive surfaces of the magnetoelectric conversion elements 20a and 20b, and the magnetic field generated by the measurement current flowing through the first portion 143 can be detected with high accuracy.

[0054] The length h1 in the thickness direction (Z-axis direction) of the connection portion between the first portion 143 and the second portion 144 is shorter than the length h3 in the thickness direction of the first portion 143 and the length h2 in the thickness direction of the second portion 144. Furthermore, the distance h5 from the second surface 144b of the second portion 144 to the second surface 143b of the first portion 143 is shorter than the length h2 in the thickness direction of the second portion 144.

[0055] A side surface 144f extending from the connection portion of the second portion 144 with the first portion 143 to the second surface 144b of the second portion 144 is aligned along the thickness direction (Z-axis direction) of the sealing portion 130. That is, the angle formed by the side surface 144f extending from the connection portion of the second portion 144 with the first portion 143 to the second surface 144b of the second portion 144 and the second surface 143b of the first portion 143 is approximately 90 degrees. Approximately 90 degrees includes 90 degrees ±5 degrees. Approximately 90 degrees includes not only exactly 90 degrees but also angles that can be considered as right angles taking into account manufacturing errors in half-blanking.

[0056] The second conductor portion 152 has a third portion 153 that supports the second surface 100b of the signal processing IC 100, and a fourth portion 154 that is connected to the third portion 153 and is located closer to the second surface 130f of the sealing portion 130 than the third portion 153, thereby forming a second step portion 155 together with the third portion 153, and is connected to the second terminal portion 151.

[0057] The second step portion 155 may be formed by half-blanking between the third portion 153 and the fourth portion 154. The third portion 153 protrudes toward the first surface 130e, which is the ceiling surface of the sealing portion 130, relative to the fourth portion 154.

[0058] 1B, the second surface 144b on the bottom side of the second portion 144 and the second surface 154b on the bottom side of the fourth portion 154 are located on the same plane. As shown in FIG. 1C, the second portion 144 and the fourth portion 154 are exposed from the second surface 130f on the bottom side of the sealing portion 130. Furthermore, the second portion 144 and the fourth portion 154 may protrude from the second surface 130f of the sealing portion 130.

[0059] 1B , a distance h5 from the second surface 144b of the second portion 144 to the second surface 143b of the first portion 143 is longer than a distance h6 corresponding to the total thickness of the third portion 153 and the signal processing IC 100. That is, the distances h2, h5, and h6 have a relationship of h2 > h5 > h6. As a result, when viewed from the direction from the first side surface 130a toward the second side surface 130b of the sealing portion 130 (the direction along the Y axis), the second conductor portion 152 and the signal processing IC 100 are located between the second surface 143b of the first portion 143 opposite the first surface 143a of the first portion 143 facing the first surface 130e of the sealing portion 130, and the second surface 144b of the second portion 144 opposite the first surface 144a of the second portion 144 facing the first surface 130e of the sealing portion 130.

[0060] That is, the third part 153 of the second conductor part 152 and the signal processing IC 100 are contained within the space defined by the plane along the second surface 143b of the first part 143, the plane along the side surface 144f of the second part 144, the second surface 130f, the third side surface 130c, the fourth side surface 130d, and the second side surface 130b of the sealing part 130.

[0061] With this configuration, by increasing the thickness of the first lead frame 140, the amount of current that can be passed through the first lead frame 140 can be increased, while the current sensor 10 can be made smaller.

[0062] Furthermore, since the second portion 144 protrudes from the second surface 130f of the sealing portion 130, heat generated in the first lead frame 140 can be released to the substrate in the shortest distance.

[0063] In the current sensor 10 according to the first embodiment, an example has been described in which the first step portion 145 and the second step portion 155 are located inside the sealing portion 130. However, at least one of the first step portion 145 and the second step portion 155 may be located outside the sealing portion 130. If at least one of the first step portion 145 and the second step portion 155 is located outside the sealing portion 130, this is disadvantageous in terms of heat dissipation. However, since the distance between the primary-side conductor and the secondary-side conductor on the substrate is longer than when the first step portion 145 and the second step portion 155 are located inside the sealing portion 130, this is advantageous in terms of voltage resistance.

[0064] 2A and 2B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to a second embodiment. Fig. 2A is a schematic plan view of the current sensor 10 according to the second embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 2B is a cross-sectional view of the current sensor 10 shown in Fig. 2A taken along line A-A.

[0065] In the current sensor 10 of the first embodiment, an example has been described in which the signal processing IC 100 and the magnetoelectric conversion elements 20a, 20b, which are Hall elements, are configured on separate chips. On the other hand, the current sensor 10 of the second embodiment differs from the current sensor 10 of the first embodiment in that the magnetoelectric conversion elements 20a, 20b, which are Hall elements, are built into the signal processing IC 100. That is, in the current sensor 10 of the second embodiment, the signal processing IC 100 and the magnetoelectric conversion elements 20a, 20b are configured on the same chip. The magnetoelectric conversion elements 20a, 20b and the signal processing IC 100 are all configured on the same chip using a silicon monolithic material.

[0066] 3A and 3B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to a third embodiment. Fig. 3A is a schematic plan view of the current sensor 10 according to the third embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 3B is a cross-sectional view of the current sensor 10 shown in Fig. 3A taken along line A-A.

[0067] The current sensor 10 according to the third embodiment differs from the current sensor 10 according to the first embodiment in the shape of the first lead frame 140 in a plan view. In the first embodiment, the first lead frame 140 is U-shaped in a plan view, but in the third embodiment, the first lead frame 140 is H-shaped in a plan view.

[0068] That is, in a plan view, the pair of first portions 146 protrude toward the second side surface 130b of the sealing portion 130 relative to the connecting portion 147. However, the pair of first portions 146 are not exposed to the outside of the sealing portion 130. The magnetoelectric conversion element 20a is disposed between the pair of first portions 146 extending toward the first terminal portion 141 in a plan view. The magnetoelectric conversion element 20b is disposed between the pair of first portions 146 extending toward the second terminal portion 151 in a plan view. That is, the magnetoelectric conversion element 20b is disposed between the pair of first portions 146 protruding toward the second terminal portion 151 relative to the connecting portion 147 in a plan view. With this configuration, the magnetoelectric conversion elements 20a and 20b can both be disposed so as to be surrounded by three side surfaces of the first conductor portion 142. Since the magnetoelectric transducer 20a and the magnetoelectric transducer 20b are surrounded by conductors of approximately the same shape, it is possible to equalize the influence of heat generated in the first conductor portion 142. Furthermore, since it is possible to equalize the coupling capacitance between the magnetoelectric transducer 20a and the magnetoelectric transducer 20b and the first conductor portion 142, it is possible to easily cancel out the coupling capacitance.

[0069] 4A and 4B show the internal configuration of a semiconductor package that functions as the current sensor 10 according to the fourth embodiment. Fig. 4A is a schematic plan view of the current sensor 10 according to the fourth embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 4B is a cross-sectional view of the current sensor 10 shown in Fig. 3A taken along line A-A.

[0070] The current sensor 10 according to the fourth embodiment differs from the current sensor 10 according to the third embodiment in that magnetoelectric conversion elements 20 a and 20 b , which are Hall elements, are built into the signal processing IC 100 .

[0071] 5A and 5B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to a fifth embodiment. Fig. 5A is a schematic plan view of the current sensor 10 according to the fifth embodiment as seen from the ceiling surface side (positive side in the Z-axis direction). Fig. 5B is a cross-sectional view of the current sensor 10 shown in Fig. 5A along line A-A. Fig. 5C is a schematic plan view of the current sensor 10 according to the fifth embodiment as seen from the bottom surface side (negative side in the Z-axis direction).

[0072] In the current sensor 10 according to the fifth embodiment, the shape of the first terminal 141 differs from the shape of the first terminal 141 of the current sensor 10 according to the third embodiment. In the fifth embodiment, each of the pair of lead terminals 141c constituting the first terminal 141 has a through hole 141d at its tip portion for electrical connection to the substrate via a bolt. Each of the pair of lead terminals 141c may have a through slit with one side open at its tip portion. Each of the pair of lead terminals 141c may have a Y-shape due to the through slit at its tip portion. Each of the pair of lead terminals 141c may be electrically connected to the substrate via the bolt by passing a bolt through the slit portion forming the Y-shape.

[0073] Fig. 6A is a schematic plan view of the current sensor 10 according to the fifth embodiment mounted on a substrate 200, as viewed from the ceiling surface side (Z-axis direction) of the current sensor 10. Fig. 6B is a schematic plan view of the current sensor 10 mounted on the substrate 200 shown in Fig. 6A, as viewed from the side side (X-axis direction).

[0074] The lead terminal 141c is fixed to the substrate 200 by a bolt 160 and a nut 162. The lead terminal 141c is electrically connected to a land 202 on the back side of the substrate 200 via the bolt 160 and the nut 162. The substrate 200 has an inverter module 170 mounted on the back side thereof, to which current flowing through the lead frame 140 is supplied. The current from the inverter module 170 may be supplied to a motor or the like that serves as a drive source for the vehicle.

[0075] The lead terminals 141c can be directly electrically connected to the inverter module 170 via bolts 160 inserted into through holes 141d provided at the tips of the lead terminals 141c, thereby eliminating the need for a copper foil pattern for electrically connecting the inverter module 170 and the lead terminals 141c.

[0076] Alternatively, a land may be provided on the mounting surface of the substrate 200, and the lead terminal 141c may be fixed to the substrate 200 by soldering. The presence of the land can enhance the heat dissipation effect. When copper foil layers are provided on the front and back surfaces of the substrate 200, the copper foil layer on the front surface and the copper foil layer on the back surface are electrically connected via bolts 160. This can significantly reduce resistance compared to when electrical connection is made only by through-hole connection.

[0077] 7A and 7B show the internal configuration of a semiconductor package that functions as a current sensor 10 according to a sixth embodiment. Fig. 7A is a schematic plan view of the current sensor 10 according to the sixth embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 7B is a cross-sectional view of the current sensor 10 shown in Fig. 7A taken along line A-A.

[0078] The current sensor 10 according to the sixth embodiment differs from the current sensor 10 according to the first embodiment in that the magnetoelectric transducers 20a and 20b are magnetoresistive elements (MR elements). Furthermore, in the first embodiment, the magnetoelectric transducers 20a and 20b are provided at positions that do not overlap the first conductor portion 142 in a plan view. However, in the sixth embodiment, the magnetoelectric transducers 20a and 20b are provided at positions that overlap the first conductor portion 142 in a plan view. The magnetoelectric transducer 20a is disposed opposite one of the pair of first portions 146. The magnetoelectric transducer 20b is disposed opposite the other of the pair of first portions 146. The magnetoelectric transducers 20a and 20b are each configured on a chip separate from the chip that configures the signal processing IC 100. The distance between the second surface 143b of each of the pair of first portions 146 (first portions 143) and the magnetically sensitive surfaces of the magnetoelectric conversion elements 20a, 20b is 50 μm to 500 μm. If this distance is shorter than 50 μm, the pressure resistance of the magnetoelectric conversion elements 20a, 20b cannot be ensured. On the other hand, if this distance is longer than 500 μm, the sensitivity of the magnetoelectric conversion elements 20a, 20b will be significantly reduced. Therefore, it is preferable that this distance be 50 μm to 500 μm.

[0079] 8A and 8B show the internal configuration of a semiconductor package that functions as the current sensor 10 according to the seventh embodiment. Fig. 8A is a schematic plan view of the current sensor 10 according to the seventh embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 8B is a cross-sectional view of the current sensor 10 shown in Fig. 8A taken along line A-A.

[0080] The current sensor 10 according to the sixth embodiment differs from the current sensor 10 according to the sixth embodiment in that the magnetoelectric conversion elements 20a, 20b, which are MR elements, are built into the signal processing IC 100. By building the magnetoelectric conversion elements 20a, 20b into the signal processing IC 100, the thickness of the current sensor 10 can be further reduced while the distance between the second surface 143b of the pair of first portions 146 (first portions 143) and the magnetic sensing surfaces of the magnetoelectric conversion elements 20a, 20b is set to between 50 μm and 500 μm.

[0081] 8C and 8D show the internal configuration of a semiconductor package that functions as the current sensor 10 according to the eighth embodiment. Fig. 8C is a schematic plan view of the current sensor 10 according to the eighth embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 8C is a cross-sectional view of the current sensor 10 shown in Fig. 8D taken along line A-A.

[0082] The second conductor 152 has a third portion 153 that supports the second surface 100b of the signal processing IC 100, and a fourth portion 154 that is connected to the third portion 153 and also connected to the second terminal 151. The fourth portion 154 includes a bending portion that bends from the connection portion with the third portion 153 in the thickness direction (Z-axis direction) of the sealing portion 130 from the second surface (bottom surface) 130f to the first surface (ceiling surface) 130e. The second terminal 151 includes a bending portion that bends from the connection portion with the fourth portion 154 in the thickness direction (z-axis direction) of the sealing portion 130 from the first surface (ceiling surface) 130e to the second surface (bottom surface) 130f. As such, the current sensor 10 of the eighth embodiment differs from the current sensor 10 of the first embodiment in that the second lead frame 150 has a bent portion of the fourth portion 154 and a bent portion of the second terminal portion 151 instead of the second step portion 155.

[0083] The bent portion of the fourth portion 154 and the bent portion of the second terminal portion 151 form a U-shape when viewed from the X-axis direction. By having such a bent portion, the second terminal portion 151 protrudes only from the second side surface 130b of the sealing portion 130. That is, relative to the second surface 141b of the first terminal portion 141 on the first side surface 130a of the sealing portion 130, the second surface 151b of the second terminal portion 151 on the second side surface 130b of the sealing portion 130 is located closer to the first surface (ceiling surface) 130e of the sealing portion 130 in the thickness direction (Z-axis direction) of the sealing portion 130. This makes it possible to increase the creepage distance (L1 + L2) on the surface of the sealing portion 130 between the first lead frame 140 on the primary side and the second lead frame 150 on the secondary side, and the creepage distance (L3) on the substrate on which the current sensor 10 is mounted, thereby providing a current sensor 10 that can more reliably ensure insulation while preventing the size of the sealing portion 130 from increasing.

[0084] 8E and 8F show the internal configuration of a semiconductor package that functions as the current sensor 10 according to the ninth embodiment. Fig. 8E is a schematic plan view of the current sensor 10 according to the ninth embodiment as viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 8F is a cross-sectional view of the current sensor 10 shown in Fig. 8E taken along line A-A.

[0085] The current sensor 10 of the ninth embodiment differs from the current sensor 10 of the first embodiment, in that the first step portion 145 formed in the first conductor portion 142 of the first lead frame 140 on the primary side is located outside the sealing portion 130, in that the first step portion 145 is located inside the sealing portion 130.

[0086] That is, with respect to the second surface 143b of the first portion 143 of the first conductor portion 142 on the first side surface 130a of the sealing portion 130, the position of the second surface 151b of the second terminal portion 151 on the second side surface 130b of the sealing portion 130 is closer to the second surface (bottom surface) 130f of the sealing portion 130 in the thickness direction (Z-axis direction) of the sealing portion 130. The second surface 143b of the first portion 143 is located closer to the first surface (ceiling surface) 130e of the sealing portion 130 than the second surface (bottom surface) 130f of the sealing portion 130 in the thickness direction (Z-axis direction) of the sealing portion 130.

[0087] With the current sensor 10 configured in this manner, the creepage distance (L1 + L2) on the surface of the sealing portion 130 between the first lead frame 140 on the primary side and the second lead frame 150 on the secondary side, and the creepage distance (L3) on the substrate on which the current sensor 10 is mounted, can each be increased, thereby providing a current sensor 10 that can more reliably ensure insulation while preventing the size of the sealing portion 130 from increasing.

[0088] According to the current sensor 10 of the ninth embodiment, the position of the second surface 151b of the second terminal portion 151 on the second side surface 130b of the sealing portion 130 relative to the second surface 143b of the first part 143 of the first conductor portion 142 on the first side surface 130a of the sealing portion 130 is different in the thickness direction (Z-axis direction) of the sealing portion 130, so that the creepage distance (L1 + L2) on the surface of the sealing portion 130 between the first lead frame 140 on the primary side and the second lead frame 150 on the secondary side on the surface of the sealing portion 130 and the creepage distance (L3) on the substrate on which the current sensor 10 is mounted can each be increased, and a current sensor 10 can be provided that can more reliably ensure insulation while preventing the size of the sealing portion 130 from increasing.

[0089] 9 is a plan view showing another example of the second lead frame 150. As shown in Fig. 9, the second conductor 152 may have a slit 153c that passes through a position facing the magnetoelectric conversion elements 20a, 20b in the thickness direction (Z-axis direction) and extends to the outer circumferential edge of the second conductor 152. This makes it possible to prevent eddy currents from being generated in the second conductor 152.

[0090] As long as the eddy currents affecting the magnetoelectric conversion elements 20 a, 20 b are cut off, the width (width in the X-axis direction) of the slit 153 c of the second conductor 152 may be narrower than the widths (widths in the X-axis direction) of the magnetoelectric conversion elements 20 a, 20 b. On the other hand, as the second conductor 152 must support the signal processing IC 100, the width (width in the X-axis direction) of the slit 153 c is narrower than the width (width in the X-axis direction) of the signal processing IC 100.

[0091] 10 is a plan view showing another example of the second lead frame 150. The second conductor 152 may have openings 153d and 153e at positions facing the magnetoelectric conversion elements 20a and 20b in the thickness direction (Z-axis direction). If the areas of the openings 153d and 153e are sufficiently larger than those of the magnetoelectric conversion elements 20a and 20b, the influence of eddy currents generated in the second conductor 152 on the magnetoelectric conversion elements 20a and 20b can be reduced.

[0092] 11A and 11B are plan views of the appearance of a semiconductor package that functions as a current sensor 10 according to a modified example. Fig. 11A is a schematic plan view of the current sensor 10 according to the modified example, viewed from the ceiling surface side (positive side in the Z-axis direction). Fig. 11B is a schematic plan view of the appearance of the current sensor 10 shown in Fig. 11A, viewed from the bottom surface side (negative side in the X-axis direction). Fig. 12 is a side view of the current sensor 10 according to the modified example, mounted on a substrate 200, viewed from the negative side in the X-axis direction.

[0093] As shown in Figures 11A and 11B, the sealing portion 130 has a plurality of grooves 132 on the first surface 130e, the second surface 130f, the third side surface 130c, and the fourth side surface 130d, surrounding the first surface 130e, the second surface 130f, the third side surface 130c, and the fourth side surface 130d.

[0094] By providing the groove 132 on the surface of the sealing portion 130, the creepage distance between the first terminal 141 on the primary side and the second terminal 151 on the secondary side can be increased compared to when the groove 132 is not provided. Therefore, even if the width in the Y direction and the height in the Z direction of the sealing portion 130 are relatively short, the creepage distance required to ensure insulation between the first terminal 141 on the primary side and the second terminal 151 on the secondary side can be satisfied. To ensure insulation, the width of the recess of the groove 132 may be 1 mm or more. Furthermore, the deeper the recess of the groove 132, the more the creepage distance can be ensured without increasing the projected area of ​​the package. This configuration makes it possible to provide a current sensor 10 that can more reliably ensure insulation while suppressing an increase in the size of the sealing portion 130.

[0095] 12 , the first terminal portion 141 may be electrically connected to the substrate 200 via a pair of lands 202, which are metal plates on the substrate 200. The second terminal portion 151 may be electrically connected to the substrate 200 via a plurality of lands 204, which are metal plates on the substrate 200. The substrate 200 may have a slit or opening extending in the X-axis direction between the pair of lands 202 and the plurality of lands 204. The length of the slit or opening in the X-axis direction may be longer than the width of the sealing portion 130 in the X-axis direction. This allows the creepage distance between the pair of lands 202 and the plurality of lands 204 to be extended.

[0096] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0097] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order.

[0098] 10 Current sensor 20a, 20b Magnetoelectric conversion element 22a, 22b, 108 Wire 100 Signal processing IC 130 Sealing portion 140 First lead frame 141 First terminal portion 141c Lead terminal 141d Through hole 142 First conductor portion 143 First portion 144 Second portion 144c Pair of second portions 145 First step portion 146 Pair of first portions 147 Connecting portion 150 Second lead frame 151 Second terminal portion 152 Second conductor portion 153 Third portion 154 Fourth portion 155 Second step portion 160 Bolt 162 Nut 170 Inverter module 200 Substrate 202 Land 204 Land

Claims

a first lead frame including at least one magnetoelectric transducer, and a first terminal portion and a first conductor portion, and a measurement current measured by the at least one magnetoelectric transducer flows through the first terminal portion and the first conductor portion; a signal processing IC arranged on a second surface side opposite to a first surface of the first conductor portion, and having a circuit surface on which the at least one magnetoelectric transducer is arranged, and processing a signal output from the at least one magnetoelectric transducer; a second lead frame including a second terminal portion arranged facing the first terminal portion across the signal processing IC in a plan view, and electrically connected to the signal processing IC, and a second conductor portion supporting with a first surface the second surface of the signal processing IC opposite to the first surface on the first conductor portion side, the second lead frame being thinner than the first lead frame and electrically insulated from the first lead frame; and a sealing portion sealing the at least one magnetoelectric transducer, at least a portion of the first conductor portion, the signal processing IC, and at least a portion of the second conductor portion, a first surface on the first surface side of the signal processing IC, a second surface of the sealing portion opposite the first surface, a first side surface on which the first terminal portion is exposed, and a second side surface on which the second terminal portion is exposed, the first conductor portion having a first portion facing the first surface of the signal processing IC and a second portion connected to the first portion and located closer to the second surface side of the sealing portion than the first portion to form a first step portion together with the first portion and connected to the first terminal portion, and when viewed in a direction from the first side surface of the sealing portion toward the second side surface, the second conductor portion and the signal processing IC are located between a second surface of the first portion opposite the first surface of the first portion facing the first surface of the sealing portion and a second surface of the second portion opposite the first surface of the second portion facing the first surface of the sealing portion.

2. A current sensor as described in claim 1, wherein the length in the thickness direction of the connection portion between the first portion and the second portion is shorter than each of the length in the thickness direction of the first portion and the length in the thickness direction of the second portion.

3. The current sensor according to claim 1, wherein a side surface extending from a connection portion of the second portion with the first portion to the second surface of the second portion is aligned along a thickness direction of the sealing portion.

4. A current sensor as described in claim 1, wherein the angle formed between the side extending from the connection portion of the second part with the first part to the second surface of the second part and the second surface of the first part is approximately 90 degrees.

5. The current sensor according to claim 1, wherein the sum of the thickness of said second lead frame and the thickness of said signal processing IC is smaller than the thickness of said first lead frame.

6. A current sensor as described in claim 1, wherein the second conductor portion has a third portion supporting the second surface of the signal processing IC, and a fourth portion connected to the third portion and positioned closer to the second surface of the sealing portion than the third portion to form a second step portion together with the third portion, and connected to the second terminal portion.

7. The current sensor according to claim 6, wherein the second surface of the second portion and a second surface of the sealing portion of the fourth portion on the second surface side are positioned on the same plane.

8. The current sensor according to claim 6, wherein the second portion and the fourth portion are exposed from the second surface of the sealing portion.

9. The current sensor according to claim 6, wherein the second portion and the fourth portion protrude from the second surface of the sealing portion.

10. A current sensor as described in claim 9, wherein a distance between a plane including a second surface of the first terminal portion opposite the first surface of the first terminal portion on the first surface side of the sealing portion and a second surface of the second terminal portion opposite the first surface of the second terminal portion on the first surface side of the sealing portion, and the second surface of the sealing portion is 1 mm or more.

11. A current sensor as described in claim 1, wherein a surface of the sealing portion of the first lead frame on the first side surface of the sealing portion facing the second surface thereof and a surface of the sealing portion of the second lead frame on the second side surface of the sealing portion facing the second surface thereof are positioned differently in a direction from the first surface of the sealing portion to the second surface of the sealing portion.

12. A current sensor as described in claim 1, wherein the first terminal portion is a pair of lead terminals, the second portion is a pair of second portions connected to each of the pair of lead terminals, and the first portion includes a pair of first portions connected to each of the pair of second portions, and a connecting portion disposed between the pair of first portions and connected to the pair of first portions.

13. The current sensor according to claim 12, wherein the at least one magnetoelectric conversion element includes a first Hall element and a second Hall element, and the first Hall element and the second Hall element are arranged opposite each other with the connecting portion interposed therebetween in a plan view.

14. The current sensor according to claim 13, wherein the first Hall element is disposed between the pair of first portions extending toward the first terminal portion from the connecting portion in a plan view.

15. The current sensor according to claim 14, wherein the second Hall element is disposed between the pair of first portions extending toward the second terminal portion from the connecting portion in a plan view.

16. The current sensor according to claim 15, wherein the pair of first portions are not exposed to the outside of the sealing portion.

17. The current sensor according to claim 13, wherein the first Hall element and the second Hall element are each configured on a chip separate from a chip that configures the signal processing IC.

18. The current sensor according to claim 13, wherein the first Hall element and the second Hall element are each built into a chip that constitutes the signal processing IC.

19. A current sensor as described in claim 12, wherein the at least one magnetoelectric conversion element includes a first magneto-resistance effect element and a second magneto-resistance effect element, the first magneto-resistance effect element is arranged opposite one of the pair of first portions, and the second magneto-resistance effect element is arranged opposite the other of the pair of first portions.

20. The current sensor according to claim 19, wherein the first magnetoresistance effect element and the second magnetoresistance effect element are each configured on a chip separate from a chip that configures the signal processing IC.

21. The current sensor according to claim 19, wherein the first magnetoresistance effect element and the second magnetoresistance effect element are each built into a chip that constitutes the signal processing IC.

22. The current sensor according to claim 19, wherein the distance between the second surface of the first portion and the magnetic sensitive surfaces of the first magnetoresistance effect element and the second magnetoresistance effect element is 50 μm to 500 μm.

23. The current sensor according to claim 6, wherein the first step portion and the second step portion are located within the sealing portion.

24. The current sensor according to claim 6, wherein at least one of the first step portion and the second step portion is located outside the sealing portion.

25. The current sensor according to claim 1, wherein the thickness of the first lead frame is 1 mm or more.

26. A current sensor as described in claim 1, wherein the second conductor portion has a slit extending in the thickness direction, passing through a position facing the at least one magnetoelectric conversion element, and extending to the outer circumferential end portion of the second conductor portion.

27. The current sensor according to claim 1, wherein the second conductor portion has an opening at a position facing the at least one magnetoelectric conversion element in the thickness direction.

28. The current sensor of claim 1, wherein the sealing portion includes a third side surface and a fourth side surface that face each other in a direction intersecting a direction from the first terminal portion to the second terminal portion, and the sealing portion has a plurality of grooves on the first surface, the second surface, the third side surface, and the fourth side surface so as to surround the first surface, the second surface, the third side surface, and the fourth side surface.

29. The current sensor according to claim 28, wherein the width of each of the plurality of grooves is 1 mm or more.

30. The current sensor according to claim 1, wherein the first terminal portion has a through hole or a through slit with one side open for electrically connecting to the board via a bolt.

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