Circuit board and electronic control device

Abstract

To provide a commonized circuit board.SOLUTION: A two-wire communication circuit is mounted on a circuit board. The circuit board includes: an electrically insulating substrate; and a conductive wiring part including a digital ground wiring 21d, a power ground wiring 21p, and an input / output pattern 5 connected to the two-wire communication circuit, and is formed on the insulating substrate. The input / output pattern includes a first conductor pattern 51 and a second conductor pattern 52, formed on at least a surface layer of the insulating substrate. The first conductor pattern is disposed adjacent to the digital ground wiring formed on the surface layer, and is configured to be connectable to the digital ground wiring at two positions symmetrically provided so as to be impedance-symmetrical. The second conductor pattern is connected to the power ground wiring formed on the surface layer, is disposed adjacent to the first conductor pattern, and is configured to be connectable to the first conductor pattern.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a circuit board and an electronic control device. [Background technology]

[0002] Patent Document 1 discloses a circuit board that is mounted with multiple ICs and other components and is assembled into an electronic device. The circuit board includes multiple mounting lands and multiple spare lands. The mounting lands are used to mount ICs and electrically connect them via wiring to other electronic components and other components mounted on the circuit board. The spare lands are used for pull-down, pull-up, and other connections when an IC is not mounted, and are formed in the IC mounting area, which is an area surrounded by the mounting lands. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-120871 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there are circuit boards on which two-wire communication circuits are mounted. Two-wire communication circuits come in a variety of types with different ground design concepts. Therefore, the circuit board needs ground wiring that is appropriate for the two-wire communication circuit mounted thereon. This poses a problem in that it is not possible to use a common circuit board for different types of two-wire communication circuits.

[0005] One disclosed object is to provide a common circuit board and electronic control unit. [Means for solving the problem]

[0006] The circuit board disclosed herein comprises: A circuit board on which a two-wire communication circuit (41) is mounted, An electrically insulating substrate (1); a conductive wiring portion (2) formed on the substrate, including a digital ground wiring (21d) for a digital circuit, a power ground wiring (21p) connected to a ground outside the substrate, and an input / output pattern (5) connected to a two-wire communication circuit; The input / output pattern is formed on at least a surface layer of the substrate, a first conductor pattern (51) arranged adjacent to the digital ground wiring formed on the surface layer and connectable to the digital ground wiring at two symmetrically arranged locations so as to have impedance symmetry; The device is characterized by comprising a second conductor pattern (52) that is connected to the power ground wiring formed on the surface layer, is arranged adjacent to the first conductor pattern, and is connectable to the first conductor pattern.

[0007] In this way, the circuit board has an input / output pattern connected to a two-wire communication circuit. The input / output pattern has a first conductor pattern connectable to a digital ground wiring and a second conductor pattern connected to a power ground wiring and connectable to the first conductor pattern. Therefore, the circuit board can be used in common for two-wire communication circuits that need to be connected to a digital ground wiring and two-wire communication circuits that need to be connected to a power ground wiring.

[0008] The electronic control device disclosed herein comprises: An electronic control device including a two-wire communication circuit (41) and a circuit board (100) on which the two-wire communication circuit is mounted, The circuit board is An electrically insulating substrate (1); a conductive wiring portion (2) formed on the substrate, including a digital ground wiring (21d) for a digital circuit, a power ground wiring (21p) connected to a ground outside the substrate, and an input / output pattern (5) connected to a two-wire communication circuit; The input / output pattern is formed on at least a surface layer of the substrate, a first conductor pattern (51) arranged adjacent to the digital ground wiring formed on the surface layer and connectable to the digital ground wiring at two symmetrically arranged locations so as to have impedance symmetry; a second conductor pattern (52) connected to the power ground wiring formed on the surface layer, arranged adjacent to the first conductor pattern, and connectable to the first conductor pattern; Furthermore, the device is characterized by comprising a connection resistance element (47) that electrically connects the first conductor pattern and the second conductor pattern.

[0009] In this way, the circuit board has an input / output pattern connected to the two-wire communication circuit. The input / output pattern has a first conductor pattern connectable to the digital ground wiring and a second conductor pattern connected to the power ground wiring and connectable to the first conductor pattern. Therefore, the electronic control device can use a common circuit board for the two-wire communication circuit that needs to be connected to the digital ground wiring and the two-wire communication circuit that needs to be connected to the power ground wiring.

[0010] Furthermore, in the electronic control device, the second conductor pattern connected to the power ground wiring is electrically connected to the first conductor pattern via a connecting resistor element. In other words, the electronic control device can use the first conductor pattern as the power ground wiring. Therefore, the electronic control device can be used in a two-wire communication circuit that requires connection to the power ground wiring.

[0011] The electronic control device disclosed herein comprises: An electronic control device including a two-wire communication circuit (41) and a circuit board (100) on which the two-wire communication circuit is mounted, The circuit board is An electrically insulating substrate (1); a conductive wiring portion (2) formed on the substrate, including a digital ground wiring (21d) for a digital circuit, a power ground wiring (21p) connected to a ground outside the substrate, and an input / output pattern (5) connected to a two-wire communication circuit; The input / output pattern is formed on at least a surface layer of the substrate, a first conductor pattern (51) arranged adjacent to the digital ground wiring formed on the surface layer and connectable to the digital ground wiring at two symmetrically arranged locations so as to have impedance symmetry; a second conductor pattern (52) connected to the power ground wiring formed on the surface layer, arranged adjacent to the first conductor pattern, and connectable to the first conductor pattern; The digital circuit further comprises a circuit element (46a, 46b) which is a resistor element or a capacitor element that electrically connects the digital ground wiring and the first conductor pattern.

[0012] In this way, the circuit board has an input / output pattern connected to the two-wire communication circuit. The input / output pattern has a first conductor pattern connectable to the digital ground wiring and a second conductor pattern connected to the power ground wiring and connectable to the first conductor pattern. Therefore, the electronic control device can use a common circuit board for the two-wire communication circuit that needs to be connected to the digital ground wiring and the two-wire communication circuit that needs to be connected to the power ground wiring.

[0013] Furthermore, in the electronic control device, the digital ground wiring and the first conductor pattern are electrically connected by a circuit element. That is, the electronic control device can use the first conductor pattern as the digital ground wiring. Therefore, the electronic control device can be used in a two-wire communication circuit that requires connection to the digital ground wiring.

[0014] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify correspondences with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a plan view showing a schematic configuration of the electronic control device. [Figure 2] FIG. 2 is an enlarged plan view showing a schematic configuration of an input / output pattern portion. [Figure 3] FIG. 2 is a layer-by-layer plan view showing a schematic configuration of a circuit board. [Figure 4] FIG. 2 is an enlarged plan view showing a schematic configuration of an input / output pattern portion. [Figure 5] FIG. 2 is an enlarged plan view showing a schematic configuration of an input / output pattern portion. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. As shown in Fig. 1, an electronic control device 1000 includes a two-wire communication circuit 41 and a circuit board 100 on which the two-wire communication circuit 41 is mounted. The electronic control device 1000 is configured to be able to communicate with other electronic devices via the two-wire communication circuit 41.

[0017] The two-wire communication circuit 41 conforms to the Ethernet (registered trademark) communication standard. The two-wire communication circuit 41 includes a transceiver, a microcomputer, and the like. The circuit board 100 is configured to be able to accommodate both a two-wire communication circuit 41 conforming to the 100BASE-T1 standard and a two-wire communication circuit 41 conforming to the 1000BASE-T1 standard. The two-wire communication circuit 41 conforming to the 100BASE-T1 standard requires connection to a power ground wiring 21p, which will be described later. On the other hand, the two-wire communication circuit 41 conforming to the 1000BASE-T1 standard requires connection to a digital ground wiring 21d, which will be described later. As such, the ground design concepts for the two-wire communication circuits 41 differ depending on the type.

[0018] However, the present disclosure is not limited to this. The two-wire communication circuit 41 may be one that complies with standards such as 10BASE-T1, 100BASE-T1S, and Gigabit Ethernet.

[0019] The electronic control device 1000 is configured to be mountable on, for example, a mobile object. Examples of the mobile object include vehicles such as electric cars, hybrid cars, and fuel cell cars, flying objects such as electric vertical take-off and landing aircraft and drones, ships, construction machinery, and agricultural machinery. In this embodiment, as an example, the electronic control device 1000 that can be mounted on a vehicle is employed. Therefore, the above Ethernet can also be called an in-vehicle Ethernet.

[0020] <Circuit board> 1, the circuit board 100 includes an electrically insulating substrate 1 and a conductive wiring portion 2. The circuit board 100 is configured so that components such as a two-wire communication circuit 41 can be mounted thereon. The insulating substrate 1 corresponds to a substrate.

[0021] The wiring section 2 has a plurality of wiring layers laminated with an insulating substrate 1 interposed therebetween. As shown in FIG. 3, the circuit board 100 has a configuration in which the wiring section 2 is laminated into six layers. The first layer L1 of the wiring section 2 can be considered a surface wiring layer. The second layer L2 to the sixth layer L6 can be considered inner wiring layers. Hereinafter, the surface wiring layers will also be referred to as surface wiring, and the inner wiring layers will also be referred to as inner wiring. However, the configuration of the circuit board 100 shown in FIG. 3 is merely an example. The surface wiring layers can also be considered as surface layers of the insulating substrate 1. The inner wiring layers can also be considered inner layers of the insulating substrate 1.

[0022] The wiring section 2 also includes digital ground wiring 21d, power ground wiring 21p, signal wiring 22, input / output patterns 5, etc. These wiring components are part of multiple wiring layers. The circuit board 100 can also be called a multi-phase wiring board. Note that FIGS. 1 and 2 illustrate surface wiring in multiple wiring layers. To make the digital ground wiring 21d and the power ground wiring 21p easier to distinguish, both wirings 21d and 21p are hatched.

[0023] The digital ground wiring 21d is wiring for digital circuits. The digital ground wiring 21d is a ground within the circuit board 100, and can therefore also be called an internal ground. At least a portion of the digital ground wiring 21d is part of the surface layer wiring. A portion of the digital ground wiring 21d may be provided on an inner layer. As shown in FIG. 1, the digital ground wiring 21d is a solid wiring.

[0024] The digital ground wiring 21d is configured to be connectable to a first conductor pattern 51, which will be described later. The digital ground wiring 21d is connectable to the first conductor pattern 51 via a first resistor element 46a and a second resistor element 46b. Therefore, as shown in FIG. 2, the digital ground wiring 21d can be said to have a first mounting portion P11 on which the first resistor element 46a is mounted, and a second mounting portion P12 on which the second resistor element 46b is mounted. Note that the term "connection" refers to an electrical connection.

[0025] The first resistor element 46a and the second resistor element 46b correspond to circuit elements. In this embodiment, the resistor elements 46a and 46b are used as an example of circuit elements. However, in the present disclosure, capacitor elements can be used instead of the resistor elements 46a and 46b.

[0026] 1, the digital ground wiring 21d is shown as being in contact with the signal wiring 22. However, the digital ground wiring 21d is electrically isolated from the signal wiring 22 by an insulating member or the like.

[0027] The power ground wiring 21p is a wiring connected to a ground outside the insulating substrate 1. Because the power ground wiring 21p is a ground outside the insulating substrate 1, it can also be called an external ground. Therefore, as shown in FIG. 2, the power ground wiring 21p is connected to a ground terminal 31 of the connector 3, which will be described later. More specifically, the ground terminal 31 is mounted on the power ground wiring 21p via solder or the like. At least a portion of the power ground wiring 21p is a part of the surface wiring. Furthermore, the power ground wiring 21p is connected to a second conductor pattern 52, which will be described later.

[0028] The signal wiring 22 is a wiring that connects the two-wire communication circuit 41 and the input / output pattern 5. The signal wiring 22 is part of the surface wiring. The signal wiring 22 is connected to the input / output pattern 5 via a choke coil 42. The signal wiring 22 can be considered to be part of the communication circuit unit that includes the two-wire communication circuit 41. The choke coil 42 is an element that complies with the standard of the two-wire communication circuit 41 mounted on the circuit board 100.

[0029] The input / output pattern 5 is wiring connected to the two-wire communication circuit 41. The input / output pattern 5 can be considered as part of the communication circuit section. The input / output pattern 5 is formed on at least the surface layer of the insulating substrate 1. In other words, part of the input / output pattern 5 is part of the surface wiring. In FIG. 1, the input / output pattern 5 is illustrated in a simplified form.

[0030] 2 and 3, the input / output pattern 5 will be described in detail. The input / output pattern 5 includes at least a first conductor pattern 51 and a second conductor pattern 52. The input / output pattern 5 is connected to an Ethernet connector. The Ethernet connector includes a signal terminal, a shield terminal, and the like. The Ethernet connector can also be called a communication connector.

[0031] The first conductor pattern 51 is disposed adjacent to the digital ground wiring 21d formed on the surface layer. The digital ground wiring 21d formed on the surface layer is a portion of the digital ground wiring 21d formed on multiple layers that is formed on the surface layer. The portion of the digital ground wiring 21d included in the surface wiring can also be referred to as the surface digital ground 21d.

[0032] The first conductor pattern 51 is configured to be connectable to the digital ground wiring 21d at two symmetrically arranged locations to achieve impedance symmetry. The symmetrically arranged locations to achieve impedance symmetry are the first conductor portion 51a and the second conductor portion 51b. Therefore, the first conductor portion 51a and the second conductor portion 51b of the first conductor pattern 51 are disposed adjacent to the digital ground wiring 21d formed on the surface layer.

[0033] The first conductor pattern 51 is disposed adjacent to the second conductor pattern 52. The first conductor pattern 51 is configured to be connectable to the second conductor pattern 52. In the present embodiment, as an example, a configuration is employed in which the second conductor pattern 52 and the second conductor portion 51b are disposed adjacent to each other.

[0034] It can also be said that the distance between the first conductor portion 51a and the second conductor portion 51b and the digital ground wiring 21d is shorter than the length of the chip of the capacitor element, resistor element, etc. It can also be said that the distance between the second conductor pattern 52 and the second conductor portion 51b is shorter than the length of the chip.

[0035] 3, first conductor patterns 51 are provided on the first layer L1 to the sixth layer L6. Therefore, at least a portion of first conductor patterns 51 is included in the surface wiring. The portion of first conductor pattern 51 that is included in the surface wiring can also be said to be first surface pattern 51. Therefore, first surface pattern 51 can be said to be disposed adjacent to surface digital ground 21d.

[0036] The first conductor patterns 51 on each layer are connected via interlayer connectors 27 and shield pins 71. In this embodiment, the first layer L1, second layer L2, third layer L3, and fourth layer L4 have the same shape, while the fifth layer L5 and sixth layer L6 have different shapes. However, the present disclosure is not limited to this. The interlayer connectors 27 can be considered part of the communication circuit unit. The shield pins 71 correspond to the shield terminals of the communication connector.

[0037] Furthermore, the first conductor pattern 51 includes the first conductor portion 51a and the second conductor portion 51b as described above. The first conductor pattern 51 only needs to include the first conductor portion 51a and the second conductor portion 51b as at least a part of the surface wiring. In this embodiment, as an example, a circuit board 100 is used that has the first conductor portions 51a and the second conductor portions 51b on the first layer L1 to the fourth layer L2. The first conductor portions 51a and the second conductor portions 51b on each layer are arranged with a gap between them. The first conductor portions 51a and the second conductor portions 51b on each layer are provided integrally.

[0038] Furthermore, the first conductor patterns 51 on the fifth layer L5 and the sixth layer L6 include wide portions 51c and 51d that are wider than the first conductor patterns 51 on the other layers. The wide portion 51d on the sixth layer L6 is partially removed. A wiring pattern that connects the interlayer connection portion 27 of the first conductor portion 51a and the interlayer connection portion 27 of the second conductor portion 51b is provided in the removed portion. Therefore, it can be said that the first conductor pattern 51 on the sixth layer L6 includes the wide portion 51d and a wiring pattern. A capacitor element 48 and a resistor element 49 are connected to the wide portion 51d and the wiring pattern. In particular, the capacitor element 48 is arranged on the center line CL of the wide portion 51d.

[0039] 2, the first conductor pattern 51 can be said to have a third mounting portion P21 on which the first resistor element 46a can be mounted and a fourth mounting portion P22 on which the second resistor element 46b can be mounted. The first conductor pattern 51 is configured to be connectable to a second conductor pattern 52, which will be described later. The first conductor pattern 51 can be connected to the second conductor pattern 52 via the third resistor element 47. Therefore, the first conductor pattern 51 can be said to have a fifth mounting portion P23 on which the third resistor element 47 can be mounted. The third resistor element 47 corresponds to a connecting resistor element.

[0040] The first conductor pattern 51 is connected to either the digital ground wiring 21d or the second conductor pattern 52. When connected to the digital ground wiring 21d, the first conductor pattern 51 functions as part of the digital ground. On the other hand, when connected to the second conductor pattern 52, the first conductor pattern 51 functions as part of the power ground.

[0041] As described above, the first conductor pattern 51 is provided on the inner layer wiring as well as on the surface layer wiring. Therefore, the circuit board 100 can improve the shielding performance (EMC performance) when the first conductor pattern 51 is connected to the digital ground wiring 21d. In other words, the circuit board 100 can improve the shielding performance when the first conductor pattern 51 functions as part of the digital ground. EMC is an abbreviation for Electro Magnetic Compatibility.

[0042] The second conductor pattern 52 is connected to the power ground wiring 21p formed on the surface layer. As described above, the second conductor pattern 52 is disposed adjacent to the first conductor pattern 51 and is configured to be connectable to the first conductor pattern 51. The power ground wiring 21p formed on the surface layer is a portion formed on the surface layer of the power ground wiring 21p formed on multiple layers.

[0043] That is, at least a part of the second conductor pattern 52 is included in the surface wiring. The part of the second conductor pattern 52 that is included in the surface wiring can also be said to be the second surface pattern 52. Therefore, it can be said that the second surface pattern 52 is disposed adjacent to the first surface pattern 51.

[0044] For example, one end of the second conductor pattern 52 is connected to the power ground wiring 21p, and the other end of the second conductor pattern 52 has a sixth mounting portion P31 on which the third resistor element 47 can be mounted.

[0045] Here, each of the mounting portions P11, P12, P21, P22, P23, and P31 can be considered to be part of the surface wiring. As shown in Fig. 2, the first mounting portion P11 and the third mounting portion P21 are arranged opposite each other. The second mounting portion P12 and the fourth mounting portion P22 are arranged opposite each other. The fifth mounting portion P23 and the sixth mounting portion P31 are arranged opposite each other.

[0046] Furthermore, the wiring section 2 includes signal wirings 23, 24 and ground wirings 25, 26. The signal wirings 23, 24 and the ground wirings 25, 26 are wirings that connect the two-wire communication circuit 41 and the input / output pattern 5. The signal wirings 23, 24 and the ground wirings 25, 26 correspond to a communication path. A portion of the communication path is disposed between the first conductor section 51a and the second conductor section 51b. The communication path can also be referred to as wiring for the communication circuit. The communication path can be considered as part of the communication circuit section.

[0047] The signal wiring 23 is a wiring for connecting the choke coil 42 and the capacitor element 43. The signal wiring 24 is a wiring for connecting the capacitor element 43 and the signal pin 61. The ground wirings 25 and 26 are wiring for connecting the signal wiring 24 and the first conductor pattern 51. The signal pin 61 corresponds to a signal terminal of the communication connector.

[0048] As described above, the circuit board 100 includes an input / output pattern 5 connected to the two-wire communication circuit 41. The input / output pattern 5 includes a first conductor pattern 51 connectable to the digital ground wiring 21d, and a second conductor pattern 52 connected to the power ground wiring 21p and connectable to the first conductor pattern 51. Therefore, the circuit board 100 can be used in common for both the two-wire communication circuit 41 that needs to be connected to the digital ground wiring 21d and the two-wire communication circuit 41 that needs to be connected to the power ground wiring 21p.

[0049] <Electronic control device> Here, electronic control device 1000 will be described with reference to Figures 1, 4, and 5. Figures 4 and 5 show a part of electronic control device 1000 including input / output pattern 5.

[0050] 1, the electronic control device 1000 includes the circuit board 100 configured as described above and a mounted component 4 mounted on the circuit board 100. The electronic control device 1000 further includes a connector 3 mounted on the circuit board 100.

[0051] 1 , the electronic control device 1000 includes, as mounted components 4, a digital circuit 40, a two-wire communication circuit 41, and a choke coil 42. The electronic control device 1000 also includes, as mounted components 4, a capacitor element 43, a resistor element 44, and an ESD protection device 45. The capacitor element 43 is connected to the signal wiring 23 and the signal wiring 24. The capacitor element 43, the resistor element 44, and the ESD protection device 45 can be considered to be part of the communication circuit section. The capacitor element 43, the resistor element 44, and the ESD protection device 45 may be included in the input / output pattern 5.

[0052] 1, the connector 3 includes a plurality of terminals 30. The plurality of terminals 30 are held in, for example, a connector case. The plurality of terminals 30 are connected to parts of the wiring section 2. The plurality of terminals 30 includes a ground terminal 31. The ground terminal 31 is connected to the power ground wiring 21p as described above.

[0053] The digital circuit 40 is connected to the terminals 30, excluding the ground terminal 31, via a part of the wiring section 2. The digital circuit 40 is also connected to the digital ground wiring 21d.

[0054] The two-wire communication circuit 41 is connected to the signal wiring 22. The choke coil 42 is connected to the signal wiring 22 and the signal wiring 23. Therefore, the two-wire communication circuit 41 is connected to the choke coil 42 via the signal wiring 22. The two-wire communication circuit 41 may also be connected to the digital circuit 40 via a part of the wiring section 2.

[0055] The resistive element 44 is connected to the signal wiring 24 and the ground wiring 25. The ESD protection device 45 is connected to the signal wiring 24 and the ground wiring .

[0056] Here, the electronic control device 1000 includes, as mounted components 4, a first resistor element 46a and a second resistor element 46b, or a third resistor element 47. Fig. 4 shows the electronic control device 1000 including the third resistor element 47. Fig. 5 shows the electronic control device 1000 including the first resistor element 46a and the second resistor element 46b.

[0057] First, the electronic control device 1000 shown in Fig. 4 will be described. Fig. 4 shows the electronic control device 1000 equipped with a two-wire communication circuit 41 that complies with the 100BASE-T1 standard. The electronic control device 1000 is equipped with a third resistor element 47 that connects the first conductor pattern 51 and the second conductor pattern 52. Furthermore, the electronic control device 1000 does not include the first resistor element 46a or the second resistor element 46b.

[0058] The third resistor element 47 has one electrode connected to the second conductor portion 51b and the other electrode connected to the second conductor pattern 52. As a result, the first conductor pattern 51 is connected to the power ground wiring 21p via the second conductor pattern 52. Therefore, the first conductor pattern 51 functions as part of the power ground.

[0059] In this way, the electronic control device 1000 includes the circuit board 100. Therefore, the electronic control device 1000 can use the same circuit board 100 for the two-wire communication circuit 41 that needs to be connected to the digital ground wiring 21d and the two-wire communication circuit 41 that needs to be connected to the power ground wiring 21p.

[0060] Furthermore, in the electronic control device 1000, the second conductor pattern 52 connected to the power ground wiring 21p and the first conductor pattern 51 are connected by a third resistor element 47. That is, the electronic control device 1000 can use the first conductor pattern 51 as the power ground wiring 21p. Therefore, the electronic control device 1000 can be compatible with a two-wire communication circuit 41 that requires connection to the power ground wiring 21p. In other words, the electronic control device 1000 can establish a communication interface for the two-wire communication circuit 41 that complies with the 100BASE-T1 standard.

[0061] Next, an electronic control device 1000 shown in Fig. 5 will be described. Fig. 5 shows an electronic control device 1000 equipped with a two-wire communication circuit 41 that complies with the 1000BASE-T1 standard. The electronic control device 1000 is equipped with a first resistor element 46a and a second resistor element 46b that connect the first conductor pattern 51 and the digital ground wiring 21d. The electronic control device 1000 does not include a third resistor element 47.

[0062] The first resistor element 46a has one electrode connected to the first conductor portion 51a and the other electrode connected to the digital ground wiring 21d. The second resistor element 46b has one electrode connected to the second conductor portion 51b and the other electrode connected to the digital ground wiring 21d. This connects the first conductor pattern 51 to the digital ground wiring 21d. Therefore, the first conductor pattern 51 functions as part of the digital ground.

[0063] In the electronic control device 1000, the digital ground wiring 21d and the first conductor pattern 51 are connected by the first resistor element 46a and the second resistor element 46b. That is, the electronic control device 1000 can use the first conductor pattern 51 as the digital ground wiring. Therefore, the electronic control device 1000 is compatible with a two-wire communication circuit 41 that requires connection to the digital ground wiring 21d. In other words, the electronic control device 1000 can establish a communication interface for the two-wire communication circuit 41 that complies with the 1000BASE-T1 standard. Note that the electronic control device 1000 can share the same circuit board 100, similar to the electronic control device 1000 shown in FIG. 4.

[0064] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, although various combinations and forms are shown in the present disclosure, other combinations and forms including only one element, more, or less than one element are also within the scope and spirit of the present disclosure. [Explanation of symbols]

[0065] 1...insulating substrate, 2...wiring portion, 21d...digital ground wiring, 21p...power ground wiring, 3...connector, 30...terminal, 31...ground terminal, 4...mounted component, 40...digital circuit, 41...two-wire communication circuit, 46a...first resistor element, 46b...second resistor element, 47...third resistor element, 5...input / output pattern, 51...first conductor pattern, 51a...first conductor portion, 51b...second conductor portion, 52...second conductor pattern, 100...circuit board, 1000...electronic control device

Claims

1. A circuit board on which a two-wire communication circuit (41) is mounted, An electrically insulating substrate (1), a conductive wiring portion (2) formed on the substrate, the conductive wiring portion (2) including a digital ground wiring (21d) for a digital circuit, a power ground wiring (21p) connected to a ground outside the substrate, and an input / output pattern (5) connected to the two-wire communication circuit; the input / output pattern is formed on at least a surface layer of the substrate; a first conductor pattern (51) arranged adjacent to the digital ground wiring formed on the surface layer and connectable to the digital ground wiring at two symmetrically arranged locations so as to have impedance symmetry; a second conductor pattern (52) connected to the power ground wiring formed on the surface layer, arranged adjacent to the first conductor pattern, and connectable to the first conductor pattern.

2. The circuit board according to claim 1 , wherein the first conductor pattern is provided on an inner layer in addition to the surface layer of the board.

3. a circuit element (46a, 46b) that is a resistor element or a capacitor element that connects the digital ground wiring and the first conductor pattern can be mounted; 3. The circuit board according to claim 1, wherein a connecting resistor element (47) for connecting the first conductor pattern and the second conductor pattern can be mounted on the circuit board.

4. An electronic control device comprising a two-wire communication circuit (41) and a circuit board (100) on which the two-wire communication circuit is mounted, The circuit board includes: An electrically insulating substrate (1), a conductive wiring portion (2) formed on the substrate, the conductive wiring portion (2) including a digital ground wiring (21d) for a digital circuit, a power ground wiring (21p) connected to a ground outside the substrate, and an input / output pattern (5) connected to the two-wire communication circuit; the input / output pattern is formed on at least a surface layer of the substrate; a first conductor pattern (51) arranged adjacent to the digital ground wiring formed on the surface layer and connectable to the digital ground wiring at two symmetrically arranged locations so as to have impedance symmetry; a second conductor pattern (52) connected to the power ground wiring formed on the surface layer, arranged adjacent to the first conductor pattern, and connectable to the first conductor pattern; The electronic control device further comprises a connection resistance element (47) that electrically connects the first conductor pattern and the second conductor pattern.

5. An electronic control device comprising a two-wire communication circuit (41) and a circuit board (100) on which the two-wire communication circuit is mounted, The circuit board includes: An electrically insulating substrate (1), a conductive wiring portion (2) formed on the substrate, the conductive wiring portion (2) including a digital ground wiring (21d) for a digital circuit, a power ground wiring (21p) connected to a ground outside the substrate, and an input / output pattern (5) connected to the two-wire communication circuit; the input / output pattern is formed on at least a surface layer of the substrate; a first conductor pattern (51) arranged adjacent to the digital ground wiring formed on the surface layer and connectable to the digital ground wiring at two symmetrically arranged locations so as to have impedance symmetry; a second conductor pattern (52) connected to the power ground wiring formed on the surface layer, arranged adjacent to the first conductor pattern, and connectable to the first conductor pattern; The electronic control device further comprises a circuit element (46a, 46b) which is a resistor element or a capacitor element that electrically connects the digital ground wiring and the first conductor pattern.

6. Further, a communication path (22 to 26) is provided to connect the two-wire communication circuit and the input / output pattern, The first conductor pattern has a first conductor portion (51a) and a second conductor portion (51b) that are symmetrically arranged with a gap therebetween, 6. The electronic control device according to claim 4, wherein a portion of the communication path is disposed between the first conductor portion and the second conductor portion.

7. Furthermore, a connector (3) for external connection mounted on the circuit board has a plurality of terminals (30, 31) connected to the wiring portion, the connector has a ground terminal as the terminal, 6. The electronic control device according to claim 4, wherein the power ground wiring is connected to the ground terminal.

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