Signal transmission device

Abstract

To provide a signal transmission device capable of miniaturizing wiring while improving dielectric strength.SOLUTION: A signal transmission device according to an embodiment includes: a first integrated circuit chip provided with a first coil that constitutes the isolation transformer; a printed circuit board provided with a second coil that is magnetically coupled with the first coil to form the insulating transformer; a second integrated circuit chip having an upper surface on which a first connection terminal and a second connection terminal provided; a first wire that electrically connects between one end of the second coil and the first connection terminal; and a second wire that electrically connects between the other end of the second coil and the second connection terminal. The second coil is formed by a wiring layer of the printed circuit board, which has a single layer structure.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This embodiment relates to a signal transmission device.

Background Art

[0002] Conventionally, for example, some signal transmission devices such as the LVDS (Low-Voltage Differential Signaling) method include an insulating transformer which is a magnetic coupling type isolator used for electrical isolation.

[0003] And, for example, in an insulating transformer using a wiring layer of an integrated circuit (IC) chip, that is, a so-called on-chip transformer, when it is necessary to satisfy a predetermined withstand voltage, instead of a single insulation structure, it is necessary to adopt a double insulation structure in which a plurality of transformers are connected in series.

[0004] In addition, since the withstand voltage of such an inter-chip film depends on the reliability of the manufacturing process, the degree of freedom is low, and the manufacturing process for improving the withstand voltage leads to an increase in cost.

[0005] Also, for example, an insulating transformer using a printed wiring board (PCB) can ensure a desired withstand voltage even with a single insulation structure if the insulating material and the thickness of the insulating layer are appropriately selected. However, in such a printed wiring board, multilayer wiring is essential, and there are many restrictions such as via diameter, so it becomes difficult to miniaturize the wiring.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] One embodiment aims to provide a signal transmission device that can improve insulation withstand voltage while enabling miniaturization of wiring. [Means for solving the problem]

[0008] One embodiment of a signal transmission device is a signal transmission device equipped with an isolation transformer, A first integrated circuit chip is provided with a first coil that constitutes the isolation transformer, A printed circuit board is provided on which a second coil is provided that magnetically couples with the first coil to constitute the isolation transformer, A second integrated circuit chip having a first connection terminal and a second connection terminal on its upper surface, A first wire electrically connects one end of the second coil to the first connecting terminal, The device comprises a second wire that electrically connects the other end of the second coil to the second connecting terminal, The aforementioned printed circuit board has only one wiring layer. The second coil is provided only in the wiring layer of the printed circuit board, which has a single-layer wiring structure. It is characterized by the following: [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a top view showing an example of a schematic configuration of a signal transmission device according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing an example of a signal transmission device along the AA line shown in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view showing an example of a signal transmission device along the BB line shown in Figure 1. [Figure 4] Figure 4 is a top view showing an example of a schematic configuration of the integrated circuit chip of the signal transmission device shown in Figure 1. [Figure 5] Figure 5 is a top view showing an example of a schematic configuration of the wiring board of the signal transmission device shown in Figure 1. [Figure 6]Figure 6 shows an example of the configuration of a signal transmission system to which the signal transmission device according to the first embodiment is applied. [Modes for carrying out the invention]

[0010] The signal transmission device according to the embodiment will be described in detail below with reference to the attached drawings. However, the present invention is not limited to these embodiments.

[0011] (First Embodiment) [Signal transmission device] Figure 1 is a top view showing an example of a schematic configuration of a signal transmission device according to the first embodiment. Figure 2 is a cross-sectional view showing an example of a schematic cross-section of the signal transmission device along line AA shown in Figure 1. Figure 3 is a cross-sectional view showing an example of a schematic cross-section of the signal transmission device along line BB shown in Figure 1. Figure 4 is a top view showing an example of a schematic configuration of an integrated circuit chip of the signal transmission device shown in Figure 1. Figure 5 is a top view showing an example of a schematic configuration of a wiring board of the signal transmission device shown in Figure 1.

[0012] Note that the structures of the signal transmission device 100 shown in Figures 1 to 5 are schematic representations, and their configurations and positional relationships may be partially simplified or omitted, and their sizes may differ from the actual devices.

[0013] The signal transmission device 100 according to the first embodiment is a signal transmission device equipped with an isolation transformer for a magnetically coupled isolator used for the electrical isolation of high-voltage and low-voltage circuits.

[0014] The signal transmission device 100 according to this first embodiment includes, for example, a first integrated circuit chip 10, a second integrated circuit chip 11, a printed wiring board (PCB) 12, a first wire Wa, a second wire Wb, and an adhesive layer N, as shown in Figures 1 to 3.

[0015] These components of the signal transmission device 100 are molded, for example, by resin (not shown).

[0016] [First integrated circuit chip] The first integrated circuit chip 10 is provided with a first coil (primary winding) L1 constituting the insulation transformer.

[0017] This first integrated circuit chip 10 includes, for example, as shown in FIGS. 1 to 4, the first coil (primary winding) L1, signal wirings Ha and Hb, and via hole wirings Va and Vb. In FIG. 1, the first coil L1 is not shown, but is shown in FIGS. 2 to 4.

[0018] The first coil L1 is provided close to the upper surface 10u of the first integrated circuit chip 10. [[ID=!5]]

[0019] In the examples of FIGS. 2 to 4, this first coil L1 has a structure formed in one wiring layer of the first integrated circuit chip 10. This first coil L1 is made of, for example, copper.

[0020] The configuration of the first coil L1 constituting the insulation transformer shown in FIGS. 2 to 4 is, for example, a winding formed in a spiral shape and includes two primary side coils L1a and L1b, but may have different shapes and may be composed of one winding or a plurality of further divided windings.

[0021] The signal wiring Ha is provided so as to extend horizontally in a lower wiring layer different from the upper wiring layer provided with the primary side coil L1a constituting the first coil L1. This signal wiring Ha is electrically connected to an integrated circuit (not shown) provided in the first integrated circuit chip 10.

[0022] The via hole wiring Va is provided so as to extend vertically between the primary side coil L1a constituting the first coil L1 and the signal wiring Ha. This via hole wiring Va electrically connects the primary side coil 1a constituting the first coil L1 and the signal wiring Ha.

[0023] The signal wiring Hb is provided in a lower wiring layer that is different from the upper wiring layer on which the primary coil L1b constituting the first coil L1 is provided, and extends laterally. This signal wiring Hb is electrically connected to an integrated circuit (not shown) provided within the first integrated circuit chip 10.

[0024] Furthermore, the via hole wiring Vb is provided so as to extend vertically between the primary coil L1b and the signal wiring Hb that constitute the first coil L1. This via hole wiring Vb is designed to electrically connect the primary coil L1b and the signal wiring Hb that constitute the first coil L1.

[0025] [Printed circuit board] The printed circuit board 12 has, for example, as shown in Figures 2 and 3, only one wiring layer S, which is a single-layer structure (not a multi-layer structure) of wiring, as the layer on which the wiring is arranged.

[0026] As shown in Figures 1 to 4, for example, this printed circuit board 12 comprises a film substrate F, a second coil (secondary winding) L2, a first coil terminal Xa, and a second coil terminal Xb.

[0027] The film substrate F has a plate-like shape that extends laterally, as shown in Figures 1 to 4, for example. The second coil L2 is provided on the upper surface of this film substrate F.

[0028] This film substrate F possesses the necessary insulating properties for use as a magnetically coupled isolator for electrical isolation. This film substrate F is composed of a resin such as polyimide. However, other insulating materials can be selected for this film substrate F, offering a high degree of freedom in selecting insulating materials for the isolation transformer.

[0029] Furthermore, the second coil L2 is provided as a secondary winding for magnetically coupling with the first coil L1, which is the primary winding, to constitute the isolation transformer, as shown in Figures 1 to 4, for example. This second coil L2 is made up of a winding that is wound laterally in a wiring layer S located on the upper surface 12u of the printed circuit board 12 and extending laterally.

[0030] In particular, in this embodiment, the second coil L2 is provided only in the wiring layer S. More specifically, the second coil L2 is configured to extend laterally and be wound around the wiring layer S of the printed circuit board 12.

[0031] By constructing the winding with only a single layer of wiring in this way, it becomes possible to miniaturize the wiring, that is, to miniaturize the second coil L2 in the wiring layer S of the printed circuit board 12, and thus the isolation transformer can be constructed in a smaller area.

[0032] In the examples shown in Figures 2 and 3, the printed circuit board 12 is fixed above the first integrated circuit 10 such that the second coil L2 is positioned above the first coil L1.

[0033] Thus, in this embodiment, the second coil is a winding having a spiral shape. The second coil L2 is made of, for example, copper.

[0034] This second coil L2 includes, for example, a secondary coil L2a and a secondary coil L2b, as shown in Figures 1 to 4.

[0035] These secondary coils L2a and L2b are arranged in a roughly figure-eight shape in the wiring layer S, as shown in Figures 1 and 4, for example.

[0036] The configuration of the second coil L2 constituting the isolation transformer shown in Figures 1 to 3 and Figure 5 is, as described above, a spiral-shaped winding and includes secondary coils L2a and L2b arranged in a roughly figure-eight shape. However, it may have different shapes and may be divided into multiple windings.

[0037] Furthermore, the first coil terminal Xa is provided on the wiring layer S and connected to one end of the second coil L2 (secondary coil L2a), as shown in Figures 1 to 4. In the example shown in Figures 1 to 4, this first coil terminal Xa is located at the center of the spiral-shaped secondary coil L2a.

[0038] Furthermore, the second coil terminal Xb is provided on the wiring layer S and connected to the other end of the second coil L2 (secondary coil L2b). In the examples shown in Figures 1 to 4, this second coil terminal Xb is located at the center of the spiral-shaped secondary coil L2b.

[0039] [Second Integrated Circuit Chip] The second integrated circuit chip 11 has, for example, a first connection terminal Ya and a second connection terminal Yb on its upper surface 11u, as shown in Figures 1, 2, and 4. In the examples shown in Figures 2 and 4, the wiring and integrated circuits connected to the first connection terminal Ya and the second connection terminal Yb are omitted in this second integrated circuit chip 11.

[0040] Here, for example, as shown in Figures 1, 2, and 4, in the second integrated circuit chip 11, no isolation transformer is placed in the region Q between the first connection terminal Ya and the second connection terminal Yb and the integrated circuit (amplifier or driver) provided within the second integrated circuit chip 11 and electrically connected to the first connection terminal Ya and the second connection terminal Yb.

[0041] This makes it possible to reduce the chip size of the second integrated circuit chip 11.

[0042] [First wire] The first wire Wa is configured to electrically connect one end of the second coil L2 to the first connecting terminal Ya.

[0043] More specifically, the first wire Wa has one end connected to the first coil terminal Xa (and via the first coil terminal Xa to one end of the second coil L2), and the other end connected to the first connection terminal Ya.

[0044] This first wire Wa is a bonding wire and is made of a metal such as gold, silver, or aluminum.

[0045] [Second wire] The second wire Wb is configured to electrically connect the other end of the second coil L2 to the second connecting terminal Yb.

[0046] More specifically, the second wire Wb has one end connected to the second coil terminal Xb (and via the second coil terminal Xb to the other end of the second coil L2), and the other end connected to the second connection terminal Yb.

[0047] This second wire Wb is a bonding wire and is made of a metal such as gold, silver, or aluminum.

[0048] [Adhesive layer] The adhesive layer N is located between the upper surface 10u of the first integrated circuit chip 10 and the lower surface of the printed circuit board 12, as shown in Figures 2 and 3. This adhesive layer N adheres (fixes) the first integrated circuit chip 10 and the printed circuit board 12.

[0049] In particular, in the examples shown in Figures 2 and 3, the printed circuit board 12 is fixed above the first integrated circuit 10 by the adhesive layer W such that the second coil L2 is positioned above the first coil L1.

[0050] This adhesive layer N is composed of, for example, a silicone adhesive. However, the material constituting this adhesive layer N can be selected from other insulating adhesives, offering a high degree of freedom in selecting the insulating material for the isolation transformer.

[0051] The signal transmission device 100 having the above configuration is constructed by first placing and fixing the printed circuit board 12 on the first integrated circuit chip 11 via an adhesive layer W, and then connecting the first and second coil terminals Xa and Xb of the printed circuit board 12 and the first and second connection terminals Ya and Yb of the second integrated circuit chip 12 with first and second wires Wa and Wb by wire bonding.

[0052] In other words, the signal transmission device 100 is configured such that an isolation transformer is formed by bonding together a first integrated circuit chip 11 on which a first coil L1 on the primary side of the isolation transformer is provided, and a printed wiring board 12 on which a second coil L2 on the secondary side of the isolation transformer is provided.

[0053] Therefore, the chip manufacturing process for forming the isolation transformer between the first integrated circuit chip 11 and the printed wiring board 12 does not require a manufacturing process with high dielectric strength, thereby reducing manufacturing costs and increasing the freedom of choice in the manufacturing process.

[0054] Furthermore, as described above, the signal transmission device 100 according to this embodiment allows for miniaturization of the wiring, which in turn allows for an increase in the number of turns and thus an increase in inductance and coupling coefficient.

[0055] Furthermore, the signal transmission device 100 according to this embodiment can reduce the area of ​​the winding region, thereby lowering manufacturing costs and improving characteristics such as EMC (Electromagnetic Compatibility), EMI (Electromagnetic Interference), and EMS (Electromagnetic Susceptibility).

[0056] As described above, the signal transmission device 100 according to this embodiment makes it possible to improve the dielectric strength while miniaturizing the wiring.

[0057] [Signal transmission system] Here, we will describe an example of the configuration of a signal transmission system to which the signal transmission device according to the first embodiment described above is applied. Figure 6 is a diagram showing an example of the configuration of a signal transmission system to which the signal transmission device is applied. In the following description, among the components shown in Figure 6, components that are the same as those shown in Figures 1 to 5 may be given the same reference numerals as those shown in Figures 1 to 5, and their descriptions may be omitted.

[0058] As shown in Figure 6, the signal transmission system 1000 transmits an input signal and outputs output signals OUTP and OUTN.

[0059] As shown in Figure 6, for example, this signal transmission system 1000 includes a primary signal circuit (semiconductor chip) 1001 to which input signals INP and INN are input, an isolated primary circuit (semiconductor chip) 1001Z that transmits signals between itself and the primary signal circuit 1001, a secondary signal circuit (semiconductor chip) 1002 that outputs output power signals OUTP and OUTN, and an isolated secondary circuit (semiconductor chip) 1002Z that transmits signals between itself and the secondary signal circuit 1002.

[0060] As shown in Figure 6, a signal transmission device 100 according to the first embodiment, which has an electrically isolated isolation transformer structure, is applied between the isolated primary circuit 1001Z and the isolated secondary circuit 1002Z, and signals are transmitted by this signal transmission device 100.

[0061] Here, for example, as shown in Figure 6, in the isolated secondary circuit 1002Z (corresponding to the second integrated circuit chip 11 of the signal transmission device 100), the first connection terminal Ya and the second connection terminal Yb are connected to the integrated circuit (amplifier and driver) provided in the second integrated circuit chip 11 by wiring, and no isolation transformer is placed in the region Q between them.

[0062] Therefore, the chip size of the isolated secondary circuit 1002Z (corresponding to the second integrated circuit chip 11 of the signal transmission device 100) can be reduced.

[0063] Furthermore, as described above, the signal transmission device 100 according to the first embodiment is designed to improve insulation withstand voltage while miniaturizing the wiring. Therefore, in the signal transmission system 1000 to which these signal transmission devices are applied, it is also possible to improve insulation withstand voltage while miniaturizing the wiring.

[0064] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0065] 100 Signal transmission device 10. First Integrated Circuit Chip 11. Second Integrated Circuit Chip 12 Printed circuit boards L1 First coil L2 Second Coil Wa 1st wire Wb 2nd wire N Adhesive layer 1000 Signal Transmission Systems

Claims

1. A signal transmission device equipped with an isolation transformer, A first integrated circuit chip is provided with a first coil that constitutes the isolation transformer, A printed circuit board is provided on which a second coil is provided that magnetically couples with the first coil to constitute the isolation transformer, A second integrated circuit chip having a first connection terminal and a second connection terminal on its upper surface, A first wire electrically connects one end of the second coil to the first connecting terminal, A second wire electrically connects the other end of the second coil to the second connecting terminal, The device comprises an adhesive layer located between the upper surface of the first integrated circuit chip and the lower surface of the printed circuit board, which adheres the first integrated circuit chip and the printed circuit board together. The aforementioned printed circuit board has only one wiring layer. The second coil is provided only in the wiring layer of the printed circuit board, which has a single-layer wiring structure. The printed circuit board is fixed above the first integrated circuit chip by the adhesive layer such that the second coil is positioned above the first coil and the first coil and the second coil are magnetically coupled to constitute the isolation transformer. The second coil is composed of a winding that is wound laterally in the wiring layer located on the upper surface of the printed circuit board and extending laterally. A signal transmission device characterized by the following features.

2. The first integrated circuit chip is A signal wiring is provided in a lower wiring layer different from the upper wiring layer on which the first coil is provided, and which electrically connects the integrated circuit provided in the first integrated circuit chip and the first coil. The system includes via-hole wiring provided between the first coil and the signal wiring, which electrically connects the first coil and the signal wiring. The signal transmission device according to feature 1.

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