Semiconductor relay

Abstract

A semiconductor relay 1 comprises: first and second lead frames 10, 20; first and second switching elements 3, 4; and a drive part 2. The first lead frame 10 has: a first mounting part 11 in which the upper surface has the first switching element 3 mounted thereon; and a first connection part 12 continuous to the lower portion of the first mounting part. The second lead frame 20 has: a second mounting part 21 in which the upper surface has the second switching element 4 mounted thereon; and a second connection part 22 continuous to the lower portion of the second mounting part. When viewed in a first direction corresponding to the direction in which the first and the second lead frames 10, 20 are aligned, the first distance D1 representing a gap between the first and the second switching elements 3, 4 is shorter than the second distance D2 representing a gap between the first and the second connection parts 12, 22.

Description

Solid State Relay

[0001] The present disclosure relates to solid state relays.

[0002] A semiconductor relay is a conventional signal transmission device that outputs an output signal from an output terminal based on an input signal input to an input terminal while isolating the input and output. Typically, this semiconductor relay is miniaturized by sealing each component in a resin package.

[0003] For example, Patent Document 1 discloses a semiconductor relay in which a photocoupler and first and second switching elements for output are sealed in the same package.

[0004] Japanese Patent Application Laid-Open No. 2022-126101

[0005] In order to increase the output of a signal transmitted by a semiconductor relay, the first and second switching elements on the output side are driven with a high voltage and a high current. Meanwhile, there is a demand for miniaturization of the semiconductor relay.

[0006] However, when a first switching element and a second switching element that are driven by a high voltage and a high current are arranged in a small package, it is difficult to reliably insulate them from each other.

[0007] The present disclosure has been made in consideration of these points, and its purpose is to provide a semiconductor relay that can be miniaturized while ensuring insulation between the first switching element and the second switching element on the output side.

[0008] To achieve the above object, a semiconductor relay according to the present disclosure includes: a first mounting portion and a first lead frame having a first connection portion located below the first mounting portion; a second mounting portion and a second connection portion located below the second mounting portion; a first switching element (MOSFET) located on an upper surface of the first mounting portion; a second switching element (MOSFET) located on the upper surface of the second mounting portion; and a driver electrically connected to the first switching element and the second switching element and configured to drive the first switching element and the second switching element. The first mounting portion and the second mounting portion are arranged side by side at a distance from each other along a first direction in which the first lead frame and the second lead frame are aligned, and the first connection portion and the second connection portion are arranged side by side at a distance from each other along the first direction. A first distance, which is the distance between the first switching element and the second switching element in the first direction, is shorter than a second distance, which is the distance between the first connection portion and the second connection portion in the first direction. The first connection portion has an upper surface that entirely contacts the lower surface of the first mounting portion, and the first connection portion and the first mounting portion are integrally formed. The second connection portion has an upper surface that entirely contacts the lower surface of the second mounting portion, and the second connection portion and the second mounting portion are integrally formed.

[0009] According to the present disclosure, it is possible to reduce the size of the semiconductor relay while reliably insulating the first switching element and the second switching element on the output side.

[0010] 6 is an equivalent circuit diagram of a semiconductor relay according to embodiment 1. FIG. 7 is a schematic diagram of a main part of the semiconductor relay according to embodiment 1 as viewed from above. FIG. 8 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 9 is a schematic diagram of an output side component of the semiconductor relay as viewed from above. FIG. 10 is a cross-sectional view taken along line V-V in FIG. 4. FIG. 11 is a schematic diagram of a main part of a semiconductor relay according to embodiment 2 as viewed from above. FIG. 12 is a cross-sectional view taken along line VII-VII in FIG. 13. FIG. 14 is an equivalent circuit diagram of a semiconductor relay according to embodiment 3. FIG. 15 is a schematic diagram of a main part of a semiconductor relay according to embodiment 3 as viewed from above. FIG. 16 is a cross-sectional view taken along line X-X in FIG.

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or its uses.

[0012] First Embodiment [Circuit Configuration and Operation of Semiconductor Relay 1] FIG. 1 is an equivalent circuit diagram of a semiconductor relay according to a first embodiment.

[0013] As shown in FIG. 1 , the semiconductor relay 1 includes a drive unit 2, a first switching element 3, a second switching element 4, a first input terminal 6, a second input terminal 7, a first output terminal 8, and a second output terminal 9.

[0014] The drive unit 2 includes an oscillator circuit 2A, a boost circuit 2B, and a drive circuit 2C. The boost circuit 2B is a known charge-pump boost circuit including capacitors C1 and C2 and diodes Di1 to Di3. The capacitors C1 and C2 are connected in series between the oscillator circuit 2A and the boost circuit 2B, respectively, to insulate the input side of the semiconductor relay 1, i.e., the first input terminal 6 and the second input terminal 7, from the output side, i.e., the first output terminal 8 and the second output terminal 9. Note that the number and connection relationship of the diodes arranged downstream of the boost circuit 2B are not particularly limited to those shown in FIG. 1 .

[0015] In this embodiment, the drive unit 2 is an IC in which the oscillator circuit 2A, the boost circuit 2B, and the drive circuit 2C are integrated on a single semiconductor chip. However, this is not particularly limited, and for example, the oscillator circuit 2A, the boost circuit 2B, and the drive circuit 2C may each be separate components. The three components may be connected by metal wires 30 (see FIG. 2 ) or electrically connected on a printed wiring board.

[0016] The first switching element 3 and the second switching element 4 are each a known vertical MOSFET.

[0017] The operation of the semiconductor relay 1 will now be described.

[0018] When an input signal is input between the first input terminal 6 and the second input terminal 7, the oscillator circuit 2A generates a first oscillation signal S1 and a second oscillation signal S2, which are pulse signals having a predetermined oscillation frequency and opposite phases to each other.

[0019] In the boost circuit 2B, a signal is generated by adding the second oscillation signal S2, which has passed through the capacitor C2 and the diode Di2, to the first oscillation signal S1, which has passed through the capacitor C1 and the diode Di1. This signal is input to the drive circuit 2C.

[0020] The drive circuit 2C is a charge / discharge circuit, and inputs a drive signal corresponding to the signal generated by the boost circuit 2B to the gate electrodes G of the first switching element 3 and the second switching element 4, respectively.

[0021] When the voltage of the drive signal output from the drive circuit 2C becomes higher than the respective threshold voltages of the first switching element 3 and the second switching element 4, the first switching element 3 and the second switching element 4 are turned on, and conduction occurs between the drain and the source. As a result, conduction occurs between the first output terminal 8 and the second output terminal 9, and the semiconductor relay 1 is closed (turned on).

[0022] On the other hand, when no input signal is input between the first input terminal 6 and the second input terminal 7, the oscillator circuit 2A does not operate, and no signal is input from the boost circuit 2B to the drive circuit 2C. As a result, the drive circuit 2C extracts and discharges the electric charge stored in the gate electrodes G of the first switching element 3 and the second switching element 4. As a result, the drain-source of each of the first switching element 3 and the second switching element 4 becomes non-conductive, the first output terminal 8 and the second output terminal 9 are disconnected, and the semiconductor relay 1 is opened (turned off).

[0023] [Mounting of semiconductor relay 1] Fig. 2 is a schematic diagram of a main part of the semiconductor relay according to the first embodiment as viewed from above. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 4 is a schematic diagram of an output side component of the semiconductor relay as viewed from above. Fig. 5 is a cross-sectional view taken along line V-V in Fig. 4.

[0024] 2 , for ease of explanation, the first input terminal 6, the second input terminal 7, and the package 40 are omitted from illustration. Also, the lead frame and / or metal wire 30 connecting the first input terminal 6 and the drive unit 2, and the lead frame and / or metal wire 30 connecting the second input terminal 7 and the drive unit 2 are omitted from illustration. Also, the oscillation circuit 2A, the boost circuit 2B, and the drive circuit 2C in the drive unit 2 are omitted from illustration.

[0025] In the following description, the stacking direction of the drive unit 2, the first switching element 3, the second switching element 4, the first lead frame 10, and the second lead frame 20 in the semiconductor relay 1 may be referred to as the up-down direction. Along the up-down direction, the side on which the drive unit 2 is arranged may be referred to as the upper side or top, and the side on which the first lead frame 10 and the second lead frame 20 are arranged may be referred to as the lower side or bottom. The direction in which the first lead frame 10 and the second lead frame 20 are aligned when viewed from above is referred to as the first direction. A view of the semiconductor relay 1 cut along an imaginary plane that includes the up-down direction and the first direction within its plane is referred to as a cross-sectional view.

[0026] In FIG. 4, the gate electrodes G and source electrodes S of the first switching element 3 and the second switching element 4 are not shown.

[0027] 2 and 3, in the semiconductor relay 1, the drive unit 2, the first switching element 3, the second switching element 4, the first lead frame 10, and the second lead frame 20 are housed in a package 40 made of insulating resin. The first switching element 3 is mounted on the first lead frame 10, and the second switching element 4 is mounted on the second lead frame 20.

[0028] The first lead frame 10 is a conductive member made of a metal such as copper, and has a first mounting portion 11 and a first connection portion 12. The first connection portion 12 is located below the first mounting portion 11, and the entire upper surface of the first connection portion 12 is in contact with the lower surface of the first mounting portion 11. The first mounting portion 11 and the first connection portion 12 are integrally formed.

[0029] Similarly, the second lead frame 20 is a conductive member made of a metal such as copper, and has a second mounting portion 21 and a second connection portion 22. The second connection portion 22 is located below the second mounting portion 21, and the entire upper surface of the second connection portion 22 is in contact with the lower surface of the second mounting portion 21. The second mounting portion 21 and the second connection portion 22 are integrally formed.

[0030] The drain electrodes D (not shown in FIGS. 2 to 5 ) of the first switching element 3 and the second switching element 4 are provided on the lower surfaces of the first switching element 3 and the second switching element 4. The first switching element 3 is disposed on the upper surface of the first mounting portion 11 of the first lead frame 10, and the upper surface of the first mounting portion 11 and the drain electrode D are electrically connected by a conductive adhesive (not shown), such as silver paste. The second switching element 4 is disposed on the upper surface of the second mounting portion 21 of the second lead frame 20, and the upper surface of the second mounting portion 21 and the drain electrode D are electrically connected by the aforementioned conductive adhesive (not shown).

[0031] 3, the bottom surfaces of the first connection portion 12 and the second connection portion 22 are exposed from the bottom surface of the package 40. The first connection portion 12 and the second connection portion 22 are electrically connected to a component on which the semiconductor relay 1 is mounted, for example, a land electrode (neither of which is shown) provided on a printed wiring board, by the aforementioned conductive adhesive (not shown).

[0032] 2 to 5, when viewed from above, the first lead frame 10 and the second lead frame 20 are arranged side by side and spaced apart from each other in the first direction. That is, the first mounting portion 11 and the second mounting portion 21 are arranged side by side and spaced apart from each other in the first direction. Furthermore, the first connecting portion 12 and the second connecting portion 22 are arranged side by side and spaced apart from each other in the first direction. Furthermore, the first switching element 3 arranged on the first lead frame 10 and the second switching element 4 arranged on the second lead frame 20 are also arranged side by side and spaced apart from each other in the first direction.

[0033] 3 and 5 , in a cross-sectional view, the side surface of the first mounting portion 11 and the side surface of the first connecting portion 12 are flush with each other on the side closer to the side surface of the package 40. On the other hand, when viewed along the first direction, the width of the first mounting portion 11 is wider than the width of the first connecting portion 12. In other words, in a cross-sectional view, the first lead frame 10 is an L-shaped member. Similarly, in a cross-sectional view, the side surface of the second mounting portion 21 and the side surface of the second connecting portion 22 are flush with each other on the side closer to the side surface of the package 40. On the other hand, when viewed along the first direction, the width of the second mounting portion 21 is wider than the width of the second connecting portion 22. In other words, in a cross-sectional view, the second lead frame 20 is an L-shaped member.

[0034] Therefore, in a cross-sectional view, the distance (third distance D3) between the first mounting portion 11 and the second mounting portion 21 in the first direction is shorter than the distance (second distance D2) between the first connecting portion 12 and the second connecting portion 22 in the first direction (D3<D2). The shapes of the first lead frame 10 and the second lead frame are obtained by etching a flat lead frame made of copper or the like. However, this is not particularly limited, and for example, the first lead frame 10 and the second lead frame may be obtained by cutting a lead frame that has been processed into a multi-gauge strip.

[0035] 2 and 4, the first switching element 3 is located inside the periphery of the first mounting portion 11. The second switching element 4 is located inside the periphery of the second mounting portion 21. Therefore, as shown in Fig. 5, in a cross-sectional view, the distance (first distance D1) between the first switching element 3 and the second switching element 4 in the first direction is shorter than the second distance D2 described above. As is clear from Fig. 5, the relationship D2 > D1 > D3 holds.

[0036] The first switching element 3 may be mounted on the first mounting portion 11 so that the side of the first switching element 3 facing the second switching element 4 and the side of the first mounting portion 11 facing the second mounting portion 21 are flush with each other. The second switching element 4 may be mounted on the second mounting portion 21 so that the side of the second switching element 4 facing the first switching element 3 and the side of the second mounting portion 21 facing the first mounting portion 11 are flush with each other. When these conditions are met simultaneously, the relationship D2 > D1 = D3 is met.

[0037] The drive unit 2 is disposed so as to straddle the upper surfaces of the first switching element 3 and the second switching element 4. The drive unit 2 and the first switching element 3 and the second switching element 4 are bonded together with an insulating adhesive (not shown), and are electrically insulated from each other at the bonded locations.

[0038] First to fourth terminals T1 to T4 are provided on the upper surface of the drive unit 2. A gate electrode G and a source electrode S are provided on the upper surface of the first switching element 3. A gate electrode G and a source electrode S are provided on the upper surface of the second switching element 4.

[0039] The first terminal T1 and the gate electrode G of the first switching element 3 are electrically connected via a metal wire 30. The second terminal T2 and the gate electrode G of the second switching element 4 are electrically connected via a metal wire 30. The third terminal T3 and the source electrode S of the first switching element 3 are electrically connected via a metal wire 30. The fourth terminal T4 and the source electrode S of the second switching element 4 are electrically connected via a metal wire 30. The source electrode S of the first switching element 3 and the source electrode S of the second switching element 4 are electrically connected via a metal wire 30. The semiconductor relay 1 shown in FIG. 1 can be realized by connecting the drive unit 2, the first switching element 3, and the second switching element 4 via multiple metal wires 30, as shown in FIGS. 2 and 3 . Furthermore, the drive unit 2, the first switching element 3, and the second switching element 4 are sealed in a package 40 made of insulating resin, so that these three components are electrically insulated from each other except for the connection portions via the metal wires 30. Furthermore, the first lead frame 10 and the second lead frame 20 are sealed in a package 40 made of insulating resin with a gap between them, so that the first lead frame 10 and the second lead frame 20 are electrically insulated from each other.

[0040] [Effects, etc.] As described above, the semiconductor relay 1 according to this embodiment includes the first lead frame 10 , the second lead frame 20 , the first switching element 3 , the second switching element 4 , and the drive unit 2 .

[0041] The first lead frame 10 has a first mounting portion 11 and a first connection portion 12 located below the first mounting portion 11. The second lead frame 20 has a second mounting portion 21 and a second connection portion 22 located below the second mounting portion 21. The first switching element 3 is located on the upper surface of the first mounting portion 11. The second switching element 4 is located on the upper surface of the second mounting portion 21. The drive unit 2 is electrically connected to the first switching element 3 and the second switching element 4 and drives the first switching element 3 and the second switching element 4.

[0042] The first connection portion 12 of the first lead frame 10 has its entire upper surface in contact with the lower surface of the first mounting portion 11, and the first connection portion 12 and the first mounting portion 11 are integrally formed. The second connection portion 22 of the second lead frame 20 has its entire upper surface in contact with the lower surface of the second mounting portion 21, and the second connection portion 22 and the second mounting portion 21 are integrally formed.

[0043] The first mounting portion 11 and the second mounting portion 21 are arranged side by side at intervals along a first direction in which the first lead frame 10 and the second lead frame 20 are arranged side by side. The first connecting portion 12 and the second connecting portion 22 are arranged side by side at intervals along the first direction.

[0044] The first distance D1, which is the distance along the first direction between the first switching element 3 and the second switching element 4, is shorter than the second distance D2, which is the distance along the first direction between the first connection portion 12 and the second connection portion 22.

[0045] In the semiconductor relay 1, by making the second distance D2 longer than the first distance D1, the second distance D2, which corresponds to the creepage distance along the first direction between the first lead frame 10 and the second lead frame 20, can be made longer. This ensures reliable electrical insulation between the first switching element 3 and the second switching element 4. Furthermore, the second distance D2 can be made longer simply by shortening the widths along the first direction of the first connecting portion 12 and the second connecting portion 22 of the first lead frame 10 and the second lead frame 20. In other words, the second distance D2 can be made longer without increasing the lengths along the first direction of the first lead frame 10 and the second lead frame 20, thereby reducing the dimension of the semiconductor relay 1 along the first direction. In other words, the semiconductor relay 1 can be made more compact.

[0046] Furthermore, a third distance D3, which is the distance between the first placement portion 11 and the second placement portion 21 in the first direction, is preferably shorter than the second distance D2.

[0047] By making the second distance D2 longer than the third distance D3, the second distance D2, which is the creepage distance described above, can be increased without increasing the lengths of the first lead frame 10 and the second lead frame 20 in the first direction. This ensures reliable electrical insulation between the first mounting portion 11 on which the first switching element 3 is mounted and the second mounting portion 21 on which the second switching element 4 is mounted. Furthermore, the dimension of the semiconductor relay 1 in the first direction can be reduced, thereby enabling the semiconductor relay 1 to be made more compact.

[0048] It is preferable that the first switching element 3 is located inside the periphery of the first mounting portion 11 and the second switching element 4 is located inside the periphery of the second mounting portion 21 .

[0049] In this way, the first distance D1 can be made longer than the third distance D3, which means that the first switching element 3 and the second switching element 4 can be reliably insulated from each other.

[0050] Furthermore, when the first switching element 3 is mounted and fixed to the first mounting portion 11 using the aforementioned conductive adhesive, the first switching element 3 is positioned inside the periphery of the first mounting portion 11, which prevents the conductive adhesive from spilling out of the first mounting portion 11. Similarly, the second switching element 4 is positioned inside the periphery of the second mounting portion 21, which prevents the conductive adhesive from spilling out of the second mounting portion 21. These features prevent the insulation distance between the first mounting portion 11 and the second mounting portion 21 from becoming shorter. Furthermore, the insulation distance between the first connecting portion 12 and the second connecting portion 22 from becoming shorter.

[0051] The driver 2 shown in this embodiment is located on the upper surface of the first switching element 3 and the upper surface of the second switching element 4. This allows the length of the metal wire (wiring) 30 connecting the driver 2 and the first switching element 3 to be the same as the length of the metal wire (wiring) 30 connecting the driver 2 and the second switching element 4. This allows the amplitude and transmission time of the signal transmitted from the driver 2 to the first switching element 3 and the second switching element 4 to be approximately the same, improving the balance of the switching operation. For example, this reduces the response delay of the semiconductor relay 1 caused by variations in the on / off timing of each switching element.

[0052] Furthermore, by positioning the drive unit 2 so that it is located on the upper surface of each of the first switching element 3 and the second switching element 4, the length of the metal wire 30 can be shortened, thereby suppressing signal transmission variations and deformation of the metal wire 30 when the semiconductor relay 1 is sealed with insulating resin.

[0053] The drive unit 2 shown in this embodiment has capacitors C1 and C2 inside the boost circuit 2B. The capacitor C1 is connected in series to one of a pair of conductive paths leading from the oscillation circuit 2A to the drive circuit 2C. The capacitor C2 is connected in series to the other of the pair of conductive paths leading from the oscillation circuit 2A to the drive circuit 2C.

[0054] The drive unit 2 has the capacitors C1 and C2 in the above-mentioned positions, thereby providing electrical insulation between the input and output of the semiconductor relay 1. Furthermore, as shown in this embodiment, when the first switching element 3 and the second switching element 4 are each MOSFETs, charging and discharging of the respective gate electrodes G can be easily performed. In other words, the first switching element 3 and the second switching element 4 can be easily turned on and off.

[0055] The first lead frame 10, the second lead frame 20, the first switching element 3, the second switching element 4, and the drive unit 2 are housed in a package 40 made of insulating resin. The lower surfaces of the first connecting portion 12 and the second connecting portion 22 are exposed from the lower surface of the package 40.

[0056] By configuring the semiconductor relay 1 in this manner, it is possible to reduce the mounting area required when mounting the semiconductor relay 1 on a circuit board, a printed wiring board, etc. Furthermore, since the distance between the first switching element 3 and the first connecting portion 12 and the distance between the second switching element 4 and the second connecting portion 22, which are locations where heat is likely to be generated, can be shortened, heat dissipation from the semiconductor relay 1 can be performed efficiently.

[0057] (Embodiment 2) Fig. 6 is a schematic diagram of a main part of a semiconductor relay according to embodiment 2 as seen from above. Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. For ease of explanation, in Figs. 6 and 7 and the following drawings, parts that are the same as those in embodiment 1 are designated by the same reference numerals, and detailed explanations thereof will be omitted.

[0058] The semiconductor relay 1 of this embodiment shown in FIGS. 6 and 7 differs from the semiconductor relay 1 of the first embodiment shown in FIGS. 2 and 3 in that the drive unit 2 is located on the upper surface of the first switching element 3.

[0059] According to this embodiment, the first switching element 3 and the first mounting portion 11 function as a support portion that supports the drive portion 2 from below. This stabilizes the position of the drive portion 2 in the semiconductor relay 1, and therefore stabilizes the operation of the semiconductor relay 1.

[0060] Furthermore, according to this embodiment, it is possible to achieve the same effect as that achieved by the configuration shown in embodiment 1. That is, the second distance D2, which is the creepage distance, can be increased, and the dimension of the semiconductor relay 1 along the first direction can be reduced, thereby achieving miniaturization of the semiconductor relay 1.

[0061] Furthermore, since the drive unit 2 has the capacitors C1 and C2 at the above-mentioned positions, it is possible to electrically insulate the input and output of the semiconductor relay 1. Furthermore, the first switching element 3 and the second switching element 4, each of which is a MOSFET, can be easily turned on and off.

[0062] Furthermore, when the first switching element 3 is located inside the periphery of the first mounting portion 11 and the second switching element 4 is located inside the periphery of the second mounting portion 21, the conductive adhesive can be prevented from spilling out from each of the first mounting portion 11 and the second mounting portion 21. This prevents the insulation distance between the first mounting portion 11 and the second mounting portion 21 from becoming shorter. Also, the insulation distance between the first connecting portion 12 and the second connecting portion 22 can be prevented from becoming shorter.

[0063] In this embodiment, the driving unit 2 is located on the upper surface of the first switching element 3. However, the driving unit 2 may be located on the upper surface of only the second switching element 4.

[0064] In this case as well, the second switching element 4 and the second mounting portion 21 function as a support portion that supports the drive portion 2 from below. This stabilizes the position of the drive portion 2 in the semiconductor relay 1, and thus stabilizes the operation of the semiconductor relay 1. Also in this case as well, the same effects as those achieved by the configuration shown in the first embodiment can be achieved.

[0065] Third Embodiment [Circuit Configuration and Operation of Semiconductor Relay 50] FIG. 8 is an equivalent circuit diagram of a semiconductor relay according to a third embodiment.

[0066] The semiconductor relay 50 shown in Fig. 8 differs from the circuit configuration of the first embodiment shown in Fig. 1 in the circuit configuration of the driver 2. That is, the driver 2 shown in Fig. 8 has a light-receiving unit 2D instead of the oscillator circuit 2A and the boost circuit 2B shown in Fig. 1. Note that, like the driver circuit 2C shown in Fig. 1, the driver circuit 2E shown in Fig. 8 is a charge / discharge circuit for the gate electrodes G of the first switching element 3 and the second switching element 4. Furthermore, the semiconductor relay 50 shown in Fig. 8 has a light-emitting element 5 disposed opposite the light-receiving unit 2D. The light-emitting element 5 is connected in series between the first input terminal 6 and the second input terminal 7.

[0067] The operation of the semiconductor relay 50 will now be described.

[0068] When an input signal is applied between the first input terminal 6 and the second input terminal 7, the light-emitting element 5 outputs an optical signal. The optical signal generated by the light-emitting element 5 is received by the light-receiving section 2D.

[0069] The light receiving unit 2D has a photodiode array. In the photodiode array, an optical signal is photoelectrically converted to generate a current, and the drive circuit 2E operates based on this current. A drive signal, which is a voltage signal corresponding to the amount of light emitted by the light emitting element 5, is applied to the gate electrodes G of the first switching element 3 and the second switching element 4 via metal wires 30.

[0070] When the voltage of the drive signal output from the drive circuit 2E becomes higher than the respective threshold voltages of the first switching element 3 and the second switching element 4, the first switching element 3 and the second switching element 4 are turned on, and conduction occurs between the drain and the source. As a result, conduction occurs between the first output terminal 8 and the second output terminal 9, and the semiconductor relay 50 is closed (turned on).

[0071] On the other hand, when the input signal is no longer input between the first input terminal 6 and the second input terminal 7, light emission from the light-emitting element 5 also stops. In response to this, current no longer flows in the photodiode array, and the drive signal from the drive circuit 2E also stops. As a result, the drive circuit 2E extracts and discharges the electric charge stored in the gate electrodes G of the first switching element 3 and the second switching element 4. As a result, the drain-source paths of the first switching element 3 and the second switching element 4 become non-conductive, the first output terminal 8 and the second output terminal 9 are disconnected, and the semiconductor relay 50 is opened (turned off).

[0072] That is, while the semiconductor relay 1 shown in FIG. 1 is a semiconductor relay in which the input and output are insulated from each other by the capacitors C1 and C2, the semiconductor relay 50 of this embodiment is a semiconductor relay in which the input and output are insulated from each other by a photocoupler constituted by the light-emitting element 5 and the light-receiving unit 2D.

[0073] [Mounting of semiconductor relay 50] Fig. 9 is a schematic diagram of a main part of a semiconductor relay according to embodiment 3 as seen from above. Fig. 10 is a cross-sectional view taken along line X-X in Fig. 9. Note that in Figs. 9 and 10, the metal wire 30 and wiring that transmit the input signal input to the light-emitting element 5 are omitted from the illustration.

[0074] The mounting mode of the semiconductor relay 50 shown in FIGS. 9 and 10 is the same as the mounting mode of the semiconductor relay 1 shown in FIGS. 2 to 5, except for the following points.

[0075] First, in the semiconductor relay 50, the drive unit 2, the first switching element 3, the second switching element 4, the first lead frame 10, the second lead frame 20, and the light-emitting element 5 are housed in a package 40 made of insulating resin. That is, the semiconductor relay 50 includes the light-emitting element 5, which is located above the drive unit 2 as shown in Fig. 10. The drive unit 2 has a light-receiving unit 2D shown in Fig. 8 at a position facing the light-emitting element 5 in the vertical direction.

[0076] As shown in this embodiment, by configuring a photocoupler with the driving unit 2 and the light emitting element 5, the input and output of the semiconductor relay 50 can be electrically insulated from each other.

[0077] More specifically, the light-emitting element 5 is located on the upper surface of the drive unit 2. Although not shown, specifically, the light-emitting element 5 is located on the upper surface of the light-receiving unit 2D. Wiring (not shown) is connected to the upper surface of the light-emitting element 5, and the first input terminal 6 or the second input terminal 7 is electrically connected to the light-emitting element 5 via the wiring. The lower surface of the light-emitting element 5 is the output surface for the optical signal. The lower surface of the light-emitting element 5 and the upper surface of the light-receiving unit 2D are connected by a light-transmitting resin (not shown). This light-transmitting resin serves as a transmission path for the optical signal. In this case, the insulating resin constituting the package 40 is preferably a light-blocking resin. This configuration prevents the optical signal output from the light-emitting element 5 from leaking into the drive circuit 2E, first switching element 3, or second switching element 4 of the drive unit 2.

[0078] Furthermore, by disposing the light emitting element 5 on the upper surface of the driving unit 2, the size of the semiconductor relay 50 in the vertical direction can be reduced, and the semiconductor relay 50 can be made more compact.

[0079] Furthermore, according to this embodiment, it is possible to achieve the same effect as that achieved by the configuration shown in embodiment 1. That is, the second distance D2, which is the creepage distance, can be increased, and the dimension of the semiconductor relay 1 along the first direction can be reduced, thereby achieving miniaturization of the semiconductor relay 1.

[0080] Furthermore, because the driver 2 is located on the top surface of the first switching element 3 and the top surface of the second switching element 4, the lengths of the metal wires (wiring) 30 connecting the driver 2 to the first switching element 3 and the second switching element 4 can be made the same. This allows the amplitude and transmission time of the signals transmitted from the driver 2 to the first switching element 3 and the second switching element 4 to be approximately the same, improving the balance of the switching operations. For example, this reduces response delays in the semiconductor relay 50 caused by variations in the on / off timing of each switching element. Furthermore, the length of the metal wires 30 can be shortened, which reduces variations in signal transmission and deformation of the metal wires 30 when the semiconductor relay 50 is sealed with insulating resin.

[0081] Furthermore, when the first switching element 3 is located inside the periphery of the first mounting portion 11 and the second switching element 4 is located inside the periphery of the second mounting portion 21, the conductive adhesive can be prevented from spilling out from each of the first mounting portion 11 and the second mounting portion 21. This prevents the insulation distance between the first mounting portion 11 and the second mounting portion 21 from becoming shorter. Also, the insulation distance between the first connecting portion 12 and the second connecting portion 22 can be prevented from becoming shorter.

[0082] Other Embodiments New embodiments can also be created by appropriately combining the components shown in Embodiments 1 to 3. For example, in the semiconductor relay 50 shown in Embodiment 3, the drive unit 2 may be arranged on the upper surface of either the first switching element 3 or the second switching element 4, as in Embodiment 2. In this case, the light-emitting element 5 is arranged so as to overlap the upper surface of either the first switching element 3 or the second switching element 4 when viewed from above.

[0083] This configuration can achieve the same effect as that achieved by the configuration shown in embodiment 2. That is, either the first switching element 3 and the first mounting portion 11 or the second switching element 4 and the second mounting portion 21 functions as a support portion that supports the drive unit 2 from below. This stabilizes the position of the drive unit 2 in the semiconductor relay 50, and ultimately stabilizes the operation of the semiconductor relay 50.

[0084] The semiconductor relay of the present disclosure is useful because it allows the semiconductor relay to be miniaturized while ensuring insulation between the first switching element and the second switching element on the output side.

[0085] REFERENCE SIGNS LIST 1, 50 Semiconductor relay 2 Drive section 2A Oscillator circuit 2B Booster circuit 2C Drive circuit 2D Light receiving section 2E Drive circuit 3 First switching element (MOSFET) 4 Second switching element (MOSFET) 5 Light emitting element 6 First input terminal 7 Second input terminal 8 First output terminal 9 Second output terminal 10 First lead frame 11 First mounting section 12 First connecting section 20 Second lead frame 21 Second mounting section 22 Second connecting section 30 Metal wire (wiring) 40 Package (insulating resin)

Claims

1. A semiconductor device comprising: a first lead frame having a first mounting portion and a first connection portion located below the first mounting portion; a second lead frame having a second connection portion located below the second mounting portion; a first switching element (MOSFET) located on an upper surface of the first mounting portion; a second switching element (MOSFET) located on an upper surface of the second mounting portion; and a drive portion electrically connected to the first switching element and the second switching element and driving the first switching element and the second switching element, wherein the first mounting portion and the second mounting portion are arranged side by side at a distance from each other along a first direction in which the first lead frame and the second lead frame are aligned, and the first connection portion and the second connection portion are arranged side by side at a distance from each other along the first direction, and a first distance which is the distance between the first switching element and the second switching element in the first direction is shorter than a second distance which is the distance between the first connection portion and the second connection portion in the first direction, a semiconductor relay, wherein the first connection portion has an upper surface that is in contact with the lower surface of the first mounting portion, and the first connection portion and the first mounting portion are integrally formed; and the second connection portion has an upper surface that is in contact with the lower surface of the second mounting portion, and the second connection portion and the second mounting portion are integrally formed.

2. The semiconductor relay according to claim 1, wherein a third distance, which is a distance between the first mounting portion and the second mounting portion along the first direction, is shorter than the second distance.

3. A semiconductor relay according to claim 1 or 2, wherein the first switching element is located inside the periphery of the first mounting portion, and the second switching element is located inside the periphery of the second mounting portion.

4. The semiconductor relay according to any one of claims 1 to 3, wherein the drive portion is located on the upper surface of the first switching element or the upper surface of the second switching element.

5. The semiconductor relay according to any one of claims 1 to 4, wherein the drive portion is located on the upper surface of the first switching element and the upper surface of the second switching element.

6. The semiconductor relay according to any one of claims 1 to 5, wherein the driving section has a capacitor.

7. A semiconductor relay according to any one of claims 1 to 5, further comprising a light-emitting element located above the drive unit, the drive unit having a light-receiving element.

8. The semiconductor relay according to claim 7, wherein the light emitting element is located on the upper surface of the driving portion.

9. A semiconductor relay as claimed in any one of claims 1 to 8, wherein the first lead frame, the second lead frame, the first switching element, the second switching element and the drive unit are housed in a package, and the lower surface of the first connection portion and the lower surface of the second connection portion are exposed from the lower surface of the package.

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