In-vehicle device

Abstract

This in-vehicle device executes a process related to communication between in-vehicle ECUs mounted on a car. The in-vehicle device comprises: a connector to which the in-vehicle ECUs are connected; a power supply circuit to which power is supplied from a power supply device mounted on the car; a connector-side conductor that is connected to the connector and determines the reference potential on the side of the connector; a circuit-side conductor that is connected to the power supply circuit and determines the reference potential on the side of the power supply circuit; and a system-in-package (SIP) substrate that is connected to the connector-side conductor and the circuit-side conductor. The SIP substrate includes: a communication unit that is connected to the connector; a processing unit that is connected to the communication unit and executes the process related to communication between the in-vehicle ECUs; and a connection element that is interposed between the connector and the communication unit. The processing unit and the communication unit are connected to the circuit-side conductor.

Description

In-vehicle device

[0001] This application claims priority to Japanese Patent Application No. 2024-086496, filed May 28, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] Patent Document 1 discloses a vehicle communication device that receives a differential signal represented by the voltage difference between two electrical signals propagating through two conductors. In this communication device, noise is removed from the two electrical signals using the potential of a first conductor as a reference potential. Furthermore, the differential signal represented by the voltage difference between the two electrical signals from which noise has been removed is converted into a voltage signal whose reference potential is the potential of a second conductor. In the communication device, a voltage whose reference potential is the potential of the first conductor is applied via a connector. The applied voltage is converted into a voltage whose reference potential is the potential of the second conductor. The converted voltage is applied to a conversion unit that converts the differential signal into a voltage signal. This supplies power to the conversion unit.

[0003] Japanese Patent Application Laid-Open No. 2020-167536

[0004] An in-vehicle device according to one embodiment of the present disclosure is an in-vehicle device that performs processing related to communication between in-vehicle ECUs mounted on a vehicle, and includes: a connector to which the in-vehicle ECU is connected; a power supply circuit to which power is supplied from a power supply device mounted on the vehicle; a connector-side conductor connected to the connector and determining a reference potential on the connector side; a circuit-side conductor connected to the power supply circuit and determining a reference potential on the power supply circuit side; and a SIP (System in Package) board connected to the connector-side conductor and the circuit-side conductor, wherein the SIP board includes a communication unit connected to the connector, a processing unit connected to the communication unit and performing processing related to communication between the in-vehicle ECUs, and a connecting element interposed between the connector and the communication unit, and the processing unit and the communication unit are connected to the circuit-side conductor.

[0005] 1 is a schematic diagram illustrating an overview of an on-board device mounted on a vehicle according to a first embodiment; FIG. 2 is a block diagram illustrating the configuration of essential parts of a main board and a SIP board provided in the on-board device; FIG. 3 is a circuit diagram illustrating the circuit configuration of electrical components mounted on the SIP board; FIG. 4 is an explanatory diagram illustrating attachment and detachment of the SIP board to the main board; FIG. 5 is an explanatory diagram illustrating a SIP board provided with terminals using side through holes; FIG. 6 is an explanatory diagram illustrating a connector side layer (connector side solid GND layer); FIG. 7 is an explanatory diagram illustrating a signal layer; FIG. 8 is an explanatory diagram illustrating a board cross-sectional image in a SIP board; FIG. 9 is an explanatory diagram illustrating a board cross-sectional image (modified example) in a SIP board; FIG. 10 is an explanatory diagram illustrating a SIP board provided with terminals using LGA according to a second embodiment; FIG. 11 is an explanatory diagram illustrating a connector side layer (connector side solid GND layer); FIG. 12 is an explanatory diagram illustrating a signal layer; FIG. 13 is an explanatory diagram illustrating a board cross-sectional image in a SIP board.

[0006] [Problem to be Solved by the Present Disclosure] The communication device described in Patent Document 1 does not take into consideration the fact that electrical components such as elements for performing communication-related processing are mounted on a SIP board.

[0007] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide an in-vehicle device in which electrical components such as elements for performing communication-related processing can be mounted on a SIP (System in Package) board.

[0008] Effect of the Present Disclosure According to one aspect of the present disclosure, it is possible to provide an in-vehicle device in which electrical components such as elements for performing communication-related processing are mounted on a SIP board.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. In addition, at least some of the embodiments described below may be combined in any desired manner.

[0010] (1) An in-vehicle device according to one aspect of the present disclosure is an in-vehicle device that performs processing related to communication between in-vehicle ECUs mounted on a vehicle, and includes: a connector to which the in-vehicle ECU is connected; a power supply circuit to which power is supplied from a power supply device mounted on the vehicle; a connector-side conductor connected to the connector and determining a reference potential on the connector side; a circuit-side conductor connected to the power supply circuit and determining a reference potential on the power supply circuit side; and a SIP (System in Package) board connected to the connector-side conductor and the circuit-side conductor, wherein the SIP board includes a communication unit connected to the connector, a processing unit connected to the communication unit and performing processing related to communication between the in-vehicle ECUs, and a connecting element interposed between the connector and the communication unit, and the processing unit and the communication unit are connected to the circuit-side conductor.

[0011] In this aspect, the on-board device includes a processing unit that processes communication between on-board ECUs, and performs processing related to communication between the on-board ECUs, such as relaying communication data transmitted and received between the on-board ECUs that are communicatively connected to the on-board device. The on-board device has a connector-side conductor that determines a reference potential (the potential of the connector-side conductor) on the connector side and a circuit-side conductor that determines a reference potential (the potential of the circuit-side conductor) on the power supply circuit side that receives power from a power supply device such as a lead battery. That is, the potential of the connector-side conductor corresponds to the reference potential on the connector side, and the potential of the circuit-side conductor corresponds to the reference potential on the power supply circuit side. The connector-side conductor and the circuit-side conductor are configured separately, i.e., the connector-side conductor and the circuit-side conductor are arranged separately. Both the connector-side conductor and the circuit-side conductor are connected to a common ground, such as a vehicle frame, and function as a ground that determines the reference potential. That is, the connector-side conductor functions as a connector-side ground (connector-side GND), and the circuit-side conductor functions as a circuit-side ground (circuit-side GND). A connecting element formed of a common mode choke coil or an inductor is interposed between the connector-side conductor (connector-side GND) and the circuit-side conductor (circuit-side GND), thereby efficiently suppressing noise generated in one conductor from propagating to the other conductor. The in-vehicle device further includes a communication unit connected to the connector and a processing unit connected to the communication unit and performing processing related to communication between the in-vehicle ECUs. The communication unit and processing unit are configured as a SIP (System in Package) board. Using the SIP board allows multiple semiconductor chips with different functions, such as various communication units compatible with different communication protocols and a processing unit formed of a microcomputer, to be integrated into a single package. In other words, by packaging various communication functions required in an in-vehicle network system using the SIP board, these various communication functions can be consolidated, reducing the cost of communication infrastructure components while ensuring the scalability and flexibility of the in-vehicle network system.Furthermore, the SIP board includes a connection element connected to the connector-side conductor and the circuit-side conductor and interposed between the connector and the communication unit. Even when the SIP board is connected to the connector-side conductor and the circuit-side conductor that form a separated configuration in this way, the connection element (common mode choke coil or inductor) interposed between the connector and the communication unit can efficiently suppress the propagation of noise generated in either the connector-side conductor or the circuit-side conductor to the other conductor, allowing the connection element to function as a separation unit.

[0012] (2) In an in-vehicle device according to one aspect of the present disclosure, the connection element includes a common mode choke coil or inductor, and is interposed between the connector side conductor and the circuit side conductor. The connection element separates the connector side conductor and the circuit side conductor by preventing fluctuations in the reference potential generated on either side from affecting the reference potential of the other side.

[0013] In this aspect, the connection element includes a common-mode choke coil or inductor. In this case, if the communication line or electric wire on which the connection element is arranged is a single wire (single conductor), the connection element is configured as a single inductor. If the communication line or electric wire on which the connection element is arranged is a double wire (two conductors), the connection element is configured as a common-mode choke coil formed by a combination of inductors connected to the respective conductors. The SIP board is connected to both the connector-side conductor and the circuit-side conductor, and a common-mode choke coil or inductor is interposed between the connector grounded to the connector-side conductor and the communication unit grounded to the circuit-side conductor, depending on the type (single wire or double wire) of communication line connecting the connector and the communication unit. Therefore, in a ground configuration in which the connector-side conductor and the circuit-side conductor are configured as separate and physically separated, by interposing a connection element configured as a common-mode choke coil or inductor on the communication line electrically connecting the connector-side conductor and the circuit-side conductor, it is possible to prevent fluctuations in the reference potential occurring on either side from affecting the reference potential of the other side. By implementing a connection element consisting of a common mode choke coil or inductor on the SIP board in this manner, AC components that could become noise in the conduction between the connector side conductor to which the SIP board is connected and the circuit side conductor can be removed by the connection element, and the separation between the connector side conductor and the circuit side conductor can be ensured from the perspective of suppressing fluctuations in the reference potential due to the interaction between these conductors.

[0014] (3) In an in-vehicle device according to one aspect of the present disclosure, the communication unit includes a CAN transceiver whose communication protocol is CAN and an Ethernet PHY unit that is compliant with Ethernet, the connector side conductor includes a CAN side conductor to which the CAN transceiver is connected via the connection element and an Ethernet side conductor to which the Ethernet PHY unit is connected via the connection element, the CAN side conductor and the Ethernet side conductor are separated, the connection elements include an Ethernet connection element connected to the Ethernet PHY unit and a CAN connection element connected to the CAN transceiver, and the Ethernet connection element and the CAN connection element are common mode choke coils.

[0015] In this aspect, the on-board device includes multiple communication units, including a CAN (Controller Area Network) transceiver supporting a CAN (Controller Area Network) communication protocol and an Ethernet PHY unit (Ethernet physical layer transceiver) supporting Ethernet. That is, the on-board device has multiple communication units with different communication protocols and functions as a multi-protocol repeater that performs protocol conversion when relaying communication data between on-board ECUs communicating using different communication protocols. In this case, the connector-side conductor includes a CAN-side conductor to which the CAN transceiver is connected via a connection element and an Ethernet-side conductor to which the Ethernet PHY unit is connected via a connection element. The CAN-side conductor and the Ethernet-side conductor are configured as separate entities and physically separated. A CAN connection element consisting of a common mode choke coil is interposed between the CAN transceiver and the connector (CAN connector). An Ethernet connection element consisting of a common mode choke coil is interposed between the Ethernet PHY unit and the connector (Ethernet connector). Therefore, the CAN connector can operate using the CAN-side conductor as a reference potential, and the Ethernet connector can operate using the Ethernet-side conductor as a reference potential, preventing fluctuations in the reference potential occurring in either connector from affecting the reference potential of the other connector. CAN and Ethernet communication lines (CAN buses, Ethernet cables) include two conductors (double wires), and communication at the physical layer in these CAN and Ethernet systems is performed using differential signals using the two conductors (double wires). In this case, the Ethernet connection element and CAN connection element included in the SIP board are common-mode choke coils, which enable them to efficiently remove common-mode noise, which is noise superimposed in phase on the two conductors (double wires).

[0016] (4) In one aspect of the in-vehicle device of the present disclosure, the communication unit includes a LIN transceiver whose communication protocol is LIN, the LIN transceiver is connected to the CAN side conductor via the connection element, and the connection element connected to the LIN transceiver is an inductor.

[0017] In this aspect, the in-vehicle device includes a plurality of communication units, each of which includes a LIN (Local Interconnect Network)-compatible LIN transceiver. A LIN connection element, which is an inductor, is disposed between the LIN transceiver and a connector (LIN connector). In this case, the LIN connector is connected to a CAN-side conductor via the connection element, and therefore the LIN connector and the CAN connector operate using the CAN-side conductor as a reference potential. The LIN communication line (LIN bus) is formed of a single conductor (single wire), and by disposing a LIN connection element (inductor) in the LIN communication line (LIN bus), AC components that could become noise can be removed by the LIN connection element.

[0018] (5) In an in-vehicle device according to one aspect of the present disclosure, the connector includes an Ethernet connector and a CAN connector, the SIP board includes an Ethernet termination resistor interposed between the Ethernet connector and the Ethernet connection element, and a CAN termination resistor interposed between the CAN connector and the CAN connection element, the Ethernet termination resistor being connected to the Ethernet side conductor, and the CAN termination resistor being connected to the CAN side conductor.

[0019] In this aspect, the SIP board includes an Ethernet termination resistor and a CAN termination resistor. The Ethernet termination resistor is disposed between the Ethernet connector and the Ethernet connection element and is connected (grounded) to the Ethernet-side conductor. The CAN termination resistor is disposed between the CAN connector and the CAN connection element and is connected (grounded) to the CAN-side conductor. By mounting the Ethernet termination resistor and the CAN termination resistor on the SIP board in this manner, it is possible to prevent reflections from occurring in the Ethernet or CAN communication lines on the SIP board. In other words, by mounting the Ethernet termination resistor and the CAN termination resistor on the SIP board, it is possible to package components that are essential from the standpoint of suppressing reflections.

[0020] (6) An in-vehicle device according to one aspect of the present disclosure includes a main board on which the SIP board is detachably mounted, and the connector and the power supply circuit are mounted on the main board.

[0021] In this aspect, the in-vehicle device includes a SIP board and a main board on which the SIP board is detachably mounted. A connector and a power supply circuit are mounted on the main board, with the connector connected (grounded) to the connector-side conductor and the power supply circuit connected (grounded) to the circuit-side conductor. That is, the connector-side conductor and the circuit-side conductor are separately mounted on the main board. A connecting element formed of a common mode choke coil or an inductor may be interposed between the power supply connector, to which an electric wire extending from the power supply device is connected, and the power supply circuit. Communication units and processing units compatible with various communication protocols are mounted on the SIP board, which is detachably mounted (attached) to the main board on which the connector and power supply circuit are mounted. The type and number of communication units and processing units, and other implementation forms, are expected to vary depending on the model or type (vehicle model) of the vehicle in which the in-vehicle device is installed. By appropriately attaching SIP boards corresponding to the implementation forms of the communication units and processing units to a standardized main board, variations in vehicle models can be accommodated.

[0022] (7) In an in-vehicle device according to one aspect of the present disclosure, the SIP board includes a signal layer connected to the connector, a connector side layer connected to the connector side conductor, and a circuit side layer connected to the circuit side conductor.

[0023] In this embodiment, the SIP board includes a signal layer connected to the communication unit, a connector-side layer connected to the connector-side conductors, and a circuit-side layer connected to the circuit-side conductors, forming a multilayer structure with these signal layers, connector layers, and circuit layers. The connector-side layer connected to the connector-side conductors has the same potential as the connector-side conductors and therefore functions as a connector-side solid GND layer that forms part of the connector-side conductors (connector-side GND). The circuit-side layer connected to the circuit-side conductors has the same potential as the circuit-side conductors and therefore functions as a circuit-side solid GND layer that forms part of the circuit-side conductors (circuit-side GND). The connector-side layer may include a CAN-side layer connected to the CAN-side conductors and an Ethernet-side layer connected to the Ethernet-side conductors. Because the SIP board is thus constructed by stacking layers on which conductors such as lands or patterns connected to the connector, connector-side conductors, or circuit-side conductors are formed, various electrical elements to be mounted can be efficiently packaged.

[0024] (8) In an in-vehicle device according to one aspect of the present disclosure, the SIP board has a plurality of terminals connected to the main board, and the plurality of terminals include signal terminals connected to the signal layer, connector side terminals connected to the connector side layer, and circuit side terminals connected to the circuit side layer, and the signal terminals and the connector side terminals are arranged on the same peripheral portion of the SIP board, and the circuit side terminals are arranged on another peripheral portion different from the peripheral portions on which the signal terminals and the connector side terminals are arranged.

[0025] In this embodiment, the SIP board has a plurality of terminals connected to the main board, i.e., the SIP board and the main board are electrically connected via these terminals. The terminals may be, for example, terminals using side through holes (edge ​​through holes), or terminals arranged in a grid pattern on the bottom surface of the SIP board, such as LGA (Land Grid Array), BGA (Ball Grid Array), or PGA (Ping Grid Array). These terminals include signal terminals connected to the signal layer, connector terminals connected to the connector layer, and circuit terminals connected to the circuit layer. The SIP board may be, for example, rectangular, with the signal terminals and connector terminals arranged on the same peripheral edge (one peripheral edge) and the circuit terminals arranged on a different peripheral edge (another peripheral edge). In this case, the one peripheral edge on which the signal terminals and connector terminals are arranged may be positioned opposite the other peripheral edge on which the circuit terminals are arranged. In this way, by arranging the signal terminals and connector side terminals that are on the connector side (the connector side conductor is the reference potential) on the same peripheral portion (one peripheral portion) of the SIP board, and arranging the circuit side terminals that are on the power supply circuit side (the circuit side conductor is the reference potential) on a peripheral portion (the other peripheral portion) located opposite the one peripheral portion, the ease of attaching and detaching the SIP board to the main board can be improved.

[0026] (9) In an in-vehicle device according to one aspect of the present disclosure, the width of the pattern formed on the connector side layer is wider than the width of the pattern formed on the signal layer.

[0027] In this embodiment, a pattern (connector-side solid GND) connected to the connector-side conductor via the connector-side terminal is formed on the connector-side layer, and a pattern connected to the connector via the signal terminal is formed on the signal layer. In this case, the width (pattern width) of the pattern (connector-side solid GND) formed on the connector-side layer is wider than the width (pattern width) of the pattern formed on the signal layer. By making the pattern width of the pattern formed on the connector-side layer, i.e., the connector-side solid GND connected to the connector-side conductor (connector-side GND) provided on the main board via the connector-side terminal, relatively wide, the connector-side solid GND can be used as a part for signal impedance control.

[0028] [Details of the embodiment of the present disclosure] The present disclosure will be specifically described with reference to the drawings showing the embodiment. An in-vehicle device 1 according to the embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0029] (Embodiment 1) Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 is a schematic diagram illustrating an overview of an in-vehicle device 1 mounted on a vehicle C according to embodiment 1. The in-vehicle device 1 is mounted on the vehicle C and is communicably connected to a plurality of in-vehicle ECUs 91 via an in-vehicle network. The communication protocol used in the in-vehicle network is, for example, LIN (Local Interconnect Network), CAN (Controller Area Network), CAN-FD, or Ethernet (registered trademark). Therefore, the in-vehicle network is configured with communication cables such as a LIN bus, a CAN bus, or an Ethernet cable.

[0030] The in-vehicle device 1 includes one or more connectors 5 to which these communication cables are connected. The connectors 5 include a LIN connector 51, a CAN connector 52, and an Ethernet connector 53, and may further include a power connector 50. A LIN bus is connected to the LIN connector 51. A CAN bus is connected to the CAN connector 52. An Ethernet cable is connected to the Ethernet connector 53.

[0031] A power cable extending from a power supply device 92 is connected to the power connector 50. The power supply device 92 is configured by, for example, a lead battery or an alternator mounted on the vehicle C.

[0032] In this embodiment, the power connector 50, the LIN connector 51, and the Ethernet connector 53 may be integrated into one integrated connector (CN1), and multiple Ethernet connectors 53 (two in this embodiment) may be integrated into another integrated connector (CN2).

[0033] The in-vehicle device 1 uses these different communication protocols to perform processing related to communication with the in-vehicle ECU 91 corresponding to each communication protocol. In this way, the in-vehicle device 1 performs relay processing according to each communication protocol as a LIN gateway, a CAN gateway, and an Ethernet switch (Layer 2 switch, Layer 3 switch), and also functions as a multi-protocol repeater that performs protocol conversion when relaying communication data between the in-vehicle ECUs 91 of these different communication protocols.

[0034] The in-vehicle device 1 includes a main board 2 and a SIP board 6. The SIP board 6 is a board configured as a module in which multiple die chips are sealed in a single package, such as a stacked SIP module in which multiple chips (electrical components) are stacked vertically. The SIP board 6 and the main board 2 are connected (conductive) by multiple terminals, and the SIP board 6 is configured to be detachable from the main board 2.

[0035] Fig. 2 is a block diagram showing the main configuration of the main board 2 and the SIP board 6 provided in the in-vehicle device 1. Fig. 3 is a circuit diagram illustrating the circuit configuration of electrical components mounted on the SIP board 6. The SIP board 6 is configured to be detachable from the main board 2, and thus corresponds to one of the electrical components mounted on the main board 2. The main board 2 also has mounted thereon connectors 5 (CN1, CN2), a power supply circuit 21, connector-side conductors 3 (CAN-side conductor 32, Ethernet-side conductor 33), circuit-side conductors 4, and a power supply connection element 630. The power supply connector 50 and the power supply circuit 21 are connected by an electric wire 202 via the power supply connection element 630.

[0036] The conductors (GND) that determine the reference potential on the main board 2 are arranged separately. That is, on the main board 2, the connector-side conductor 3 (connector GND) that determines the reference potential on the connector 5 side and the circuit-side conductor 4 (circuit GND) that determines the reference potential on the power supply circuit 21 side are configured separately, i.e., the connector-side conductors 3 and the circuit-side conductors 4 are arranged separately. The connector-side conductors 3 include a CAN-side conductor 32 (CN1-side conductor) that determines the reference potential on the CAN connector 52 side and an Ethernet-side conductor 33 (CN2-side conductor) that determines the reference potential on the Ethernet connector 53 side. The CAN-side conductor 32 (CN1-side conductor) and the Ethernet-side conductor 33 (CN2-side conductor) are configured separately and arranged separately. Note that a common mode choke coil or inductor may be interposed between the CAN-side conductor 32 (CN1-side conductor) and the Ethernet-side conductor 33 (CN2-side conductor).

[0037] The power supply circuit 21 mounted on the main board 2 includes, for example, a voltage regulator, and reduces the voltage applied from the power supply device 92 to an operating voltage for each electrical component, such as the processing unit 62 or the communication unit 61, before outputting the voltage. A power supply connection element 630, which is configured as a common mode choke coil or inductor, is interposed between the electric wire 202 connecting the power supply connector 50 (CN1) and the power supply circuit 21. An electric wire 202 grounded to the CAN-side conductor 32 (CN1-side conductor) and an electric wire 202 grounded to the circuit-side conductor 4 (circuit GND) extend from the power supply connection element 630. Therefore, the reference potential of the electric wire 202 located on the side of the power supply connector 50 relative to the power supply connector 50 and the power supply connection element 630 is determined by the CAN-side conductor 32 (CN1-side conductor). The reference potential of the electric wire 202 located on the side of the power supply circuit 21 relative to the power supply circuit 21 and the power supply connection element 630 is determined by the circuit-side conductor 4 (circuit GND).

[0038] The SIP board 6 is mounted with a communication unit 61, a processing unit 62, and connection elements 63 (a LIN connection element 631, a CAN connection element 632, and an Ethernet connection element 633) connected to the communication unit 61. The connectors 5 and connection elements 63 corresponding to each communication protocol are connected by respective communication lines 201. The processing unit 62 includes a computing element such as a CPU or an MPU, and is configured by a microcomputer including a storage unit such as a ROM or RAM. The communication unit 61 is a communication I / F corresponding to each communication protocol, and includes a LIN transceiver 611, a CAN transceiver 612, and an Ethernet PHY unit 613 (Ethernet physical layer transceiver).

[0039] One end of the LIN transceiver 611 is connected to the LIN connector 51 via the LIN connection element 631, and the other end is connected to the processing unit 62. The LIN connection element 631 is an inductor. The LIN connector 51, the LIN connection element 631, and the LIN transceiver 611 are connected by one conductor (single wire).

[0040] One end of the CAN transceiver 612 is connected to the CAN connector 52 via a CAN connection element 632, and the other end is connected to the processing unit 62. The CAN connection element 632 is a common mode choke coil. The CAN connector 52, the CAN connection element 632, and the CAN transceiver 612 are connected by two conductors (double wires).

[0041] One end of the Ethernet PHY unit 613 is connected to the Ethernet connector 53 via an Ethernet connection element 633, and the other end is connected to the processing unit 62. The Ethernet connection element 633 is a common mode choke coil. The Ethernet connector 53, the Ethernet connection element 633, and the Ethernet PHY unit 613 are connected by two conductors (double wires).

[0042] Voltages corresponding to the respective electrical components are applied from the power supply circuit 21 to the LIN transceiver 611, the CAN transceiver 612, the Ethernet PHY unit 613, and the processing unit 62. The LIN transceiver 611, the CAN transceiver 612, the Ethernet PHY unit 613, and the processing unit 62 are grounded to the circuit-side conductor 4 (circuit GND). Therefore, the LIN transceiver 611, the CAN transceiver 612, the Ethernet PHY unit 613, and the processing unit 62 operate using the potential of the circuit-side conductor 4 (circuit GND) as their reference potential.

[0043] A CAN termination resistor 72 and an Ethernet termination resistor 73 are mounted on the SIP board 6. The CAN termination resistor 72 is configured by connecting two conductors (double wires) that make up the communication line 201 with two resistors connected in series, and grounding a branch line between these two series-connected resistors to the CAN-side conductor 32 (CN1-side GND) via a capacitor. A capacitor may be disposed between each of the two conductors of the communication line 201 located between the CAN termination resistor 72 and the CAN connection element 632.

[0044] The Ethernet termination resistor 73 is configured by connecting two conductors (double wires) that make up the communication line 201 with two resistors connected in series, and grounding a branch line between these two resistors connected in series to the Ethernet side conductor 33 (CN2 side GND) via a capacitor. A capacitor may be disposed between each of the two conductors of the communication line 201 located between the Ethernet termination resistor 73 and the Ethernet connection element 633.

[0045] The communication line 201 located between the connection element 63 and the connector 5 includes a communication line 201 mounted on the SIP board 6 and a communication line 201 mounted on the main board 2. That is, the communication lines 201 connected to the LIN connector 51, the CAN connector 52, and the Ethernet connector 53 are formed by joining the communication line 201 mounted on the SIP board 6 and the communication line 201 mounted on the main board 2.

[0046] The communication line 201 located between the connection element 63 and the connector 5 is grounded to the connector-side conductor 3 (CAN-side conductor 32, Ethernet-side conductor 33). Therefore, the communication line 201 located between the connection element 63 and the connector 5 and mounted on the SIP board 6 is also grounded to the connector-side conductor 3 (CAN-side conductor 32, Ethernet-side conductor 33). That is, in the communication line 201 located between the connection element 63 and the connector 5, the communication line 201 connected to the LIN connector 51 is grounded to the CAN-side conductor 32 (CN1-side GND). The communication line 201 connected to the CAN connector 52 is grounded to the CAN-side conductor 32 (CN1-side GND). The communication line 201 connected to the Ethernet connector 53 is grounded to the Ethernet-side conductor 33 (CN2-side GND).

[0047] A suppressor 301 is also mounted on the main board 2. The suppressor 301 is disposed on each communication line 201 located on the connector 5 side with respect to the connection element 63. The suppressor 301 is configured with, for example, a suppressor, a varistor, a capacitor, a Zener diode, or a diode clamp circuit, and functions as a surge countermeasure.

[0048] Each suppressor 301 branched from and connected to each of these communication lines 201 is grounded to the CAN side conductor 32 (CN1 side GND) or the Ethernet side conductor 33 (CN2 side GND). That is, in the communication lines 201 located on the connector 5 side with respect to the connection element 63, the suppressor 301 arranged on the communication line 201 connected to the LIN connector 51 is grounded to the CAN side conductor 32 (CN1 side GND). The suppressor 301 arranged on the communication line 201 connected to the CAN connector 52 is grounded to the CAN side conductor 32 (CN1 side GND). The suppressor 301 arranged on the communication line 201 connected to the Ethernet connector 53 is grounded to the Ethernet side conductor 33 (CN2 side GND).

[0049] The main board 2 is further equipped with a second processing unit 22 (microcomputer), a second Ethernet connector 23, a second Ethernet connection element 24, and a second Ethernet PHY unit 25. The second processing unit 22, the second Ethernet connection element 24, and the second Ethernet PHY unit 25 mounted on the main board 2 have the same configuration as the processing unit 62, the Ethernet connection element 633, and the second Ethernet PHY unit 25 mounted on the SIP board 6. The second processing unit 22 mounted on the main board 2 and the processing unit 62 mounted on the SIP board 6 may be connected to each other via a communication line 201 using an SPI communication interface (Serial Peripheral Interface) so as to be able to communicate with each other. The second Ethernet connector 23 has the same configuration as the above-mentioned Ethernet connector 53, and may be integrated into the integrated connector (CN2).

[0050] The second processing unit 22 (microcomputer), second Ethernet connector 23, second Ethernet connection element 24, and second Ethernet PHY unit 25 may be electrical components fixedly mounted on the in-vehicle device 1 and may constitute the minimum configuration of the in-vehicle device 1. In this embodiment, the second processing unit 22 (microcomputer), second Ethernet connector 23, and second Ethernet connection element 24 are mounted on the main board 2, i.e., not mounted on the SIP board 6, but this is not limitative and they may be mounted on the SIP board 6 like the processing unit 62, etc.

[0051] 4 is an explanatory diagram illustrating the attachment and detachment of the SIP board 6 to the main board 2. The main board 2 has an area (mounting area) for mounting the SIP board 6, and the mounting area has terminals (terminals of the main board 2) that mate with the terminals of the SIP board 6. When the SIP board 6 is attached to the main board 2, the communication line 201 provided on the SIP board 6 and the communication line 201 provided on the main board 2 are electrically connected (joined) by the terminals.

[0052] The LIN communication line 201 mounted on the SIP board 6 and the LIN communication line 201 mounted on the main board 2 are connected by a LIN signal terminal 811. The CAN communication line 201 mounted on the SIP board 6 and the CAN communication line 201 mounted on the main board 2 are connected by a CAN signal terminal 812. The Ethernet communication line 201 mounted on the SIP board 6 and the Ethernet communication line 201 mounted on the main board 2 are connected by an Ethernet signal terminal 813.

[0053] The main board 2 is mounted with a plurality of conductors (GND) arranged separately, and the SIP board 6 is also provided with conductors (GND) corresponding to the conductors (GND) of the main board 2. In other words, these separated conductors (CAN side conductor 32 (CN1 side GND), Ethernet side conductor 33 (CN2 side GND), and circuit side conductor 4 (circuit GND)) are essentially mounted on both the main board 2 and the SIP board 6. Therefore, even within the SIP board 6, the conductors (CAN side conductor 32 (CN1 side GND), Ethernet side conductor 33 (CN2 side GND), and circuit side conductor 4 (circuit GND)) are configured as separate entities and arranged physically separated from one another.

[0054] These conductors in the SIP board 6 may be formed on any layer (solid GND layer) of the laminated structure of the SIP board 6. Therefore, by attaching the SIP board 6 to the main board 2, the CAN side conductor 32 (CN1 side GND) of the SIP board 6 is connected to the CAN side conductor 32 (CN1 side GND) of the main board 2, the Ethernet side conductor 33 (CN2 side GND) of the SIP board 6 is connected to the Ethernet side conductor 33 (CN2 side GND) of the main board 2, and the circuit side conductor 4 (circuit GND) of the SIP board 6 is connected to the circuit side conductor 4 (circuit GND) of the main board 2.

[0055] The CAN side conductor 32 (CN1 side GND) of the SIP board 6 and the CAN side conductor 32 (CN1 side GND) of the main board 2 are connected by a CAN connector side terminal 822. The Ethernet side conductor 33 (CN2 side GND) of the SIP board 6 and the Ethernet side conductor 33 (CN2 side GND) of the main board 2 are connected by an Ethernet connector side terminal 823. The circuit side conductor 4 (circuit GND) of the SIP board 6 and the circuit side conductor 4 (circuit GND) of the main board 2 are connected by a circuit side terminal 831.

[0056] FIG. 5 is an explanatory diagram illustrating an SIP board 6 equipped with terminals using side-through holes. FIG. 6 is an explanatory diagram illustrating a connector-side layer 82 (connector-side solid GND layer). FIG. 7 is an explanatory diagram illustrating a signal layer 81. FIG. 8 is an explanatory diagram illustrating a cross-sectional image of the SIP board 6. The SIP board 6 is configured by stacking multiple layers, including a signal layer 81, a connector-side layer 82, a circuit-side layer 83, and a top layer on which electrical components (semiconductor elements) such as the communication unit 61 or the processing unit 62 are mounted. In this case, layers grounded to ground, such as the connector-side layer 82 and the circuit-side layer 83, may be configured on the same level (solid GND layer). In this embodiment, the signal layer 81 is configured on the top layer on which electrical components (semiconductor elements) such as the communication unit 61 or the processing unit 62 are mounted. In other words, the signal layer 81 corresponds to the top layer. The connector side layer 82 and the circuit side layer 83 are configured in the same hierarchical layer as a solid GND layer, and this solid GND layer is located immediately below the signal layer 81, which is the uppermost layer.

[0057] The rectangular SIP board 6 has two opposing peripheral edges (edges). A plurality of terminals are arranged on these two peripheral edges (edges) using side through holes. The signal layer 81, connector side layer 82, and circuit side layer 83 are connected to the corresponding terminals. The patterns and terminals formed on these layers may be connected (conductive) to each other via a plurality of side through holes formed on the peripheral edges (edges) of the SIP board 6 and aligned in the stacking direction, through holes formed through the SIP board 6 in the stacking direction, or an interposer.

[0058] Of the two peripheral portions (end portions), one peripheral portion (end portion) is provided with signal terminals (LIN signal terminals 811, CAN signal terminals 812, Ethernet signal terminals 813) connected to the signal layer 81 and connector side terminals (CAN connector side terminals 822, Ethernet connector side terminals 823) connected to the connector side layer 82. The other peripheral portion (end portion) is provided with circuit side terminals 831 connected to the circuit side layer 83.

[0059] The signal layer 81 is formed with patterns or lands that connect each communication unit 61 to a signal terminal corresponding to the communication unit 61. That is, the signal layer 81 is formed with a pattern extending from the LIN transceiver 611 to the LIN signal terminal 811, a pattern extending from the CAN transceiver 612 to the CAN connection element 632, and a pattern extending from the Ethernet PHY unit 613 to the Ethernet signal terminal 813. Communication data flows from the in-vehicle ECU 91 connected to the connector 5 via the patterns formed on the signal layer 81.

[0060] The connector side layer 82 has patterns or lands formed thereon that are connected to CAN connector side terminals 822 or Ethernet connector side terminals 823. The CAN connector side terminals 822 are connected (grounded) to the CAN side conductor 32 (CN1 side GND) of the main board 2. The Ethernet connector side terminals 823 are connected (grounded) to the Ethernet side conductor 33 (CN2 side GND) of the main board 2.

[0061] Therefore, in the connector-side layer 82, the patterns connected to the CAN connector-side terminals 822 correspond to the CAN-side conductors 32 (intra-SIP CAN-side conductors 32) in the SIP board 6. In the connector-side layer 82, the patterns connected to the Ethernet connector-side terminals 823 correspond to the Ethernet-side conductors 33 (intra-SIP Ethernet-side conductors 33) in the SIP board 6. In other words, even in the SIP board 6, the conductors (GND) on which the communication units 61 (CAN transceiver 612, Ethernet PHY unit 613) corresponding to the communication protocol are respectively installed are configured as separate entities and arranged physically separated from each other.

[0062] In this case, the width of the pattern formed on the connector side layer 82 may be wider than the width of the pattern formed on the signal layer 81. In other words, by making the pattern width of the pattern formed on the connector side layer 82 (connector side solid GND) relatively wide, the connector side solid GND can be used as a portion for controlling the impedance of the signal.

[0063] The circuit-side layer 83 has a pattern or land formed thereon that is connected to the circuit-side terminal 831; that is, the circuit-side layer 83 corresponds to a circuit-side solid GND layer. The circuit-side terminal 831 is connected (grounded) to the circuit-side conductor 4 (circuit GND) of the main board 2. Therefore, the pattern or the like connected to the circuit-side terminal 831 in the circuit-side layer 83 corresponds to the circuit-side conductor 4 (circuit GND) in the SIP board 6. In this way, in the SIP board 6, as in the SIP board 6, the CAN-side conductor 32 (CN1-side GND), the Ethernet-side conductor 33 (CN2-side GND), and the circuit-side conductor 4 (circuit GND) are configured as substantially separate entities and are arranged physically separated.

[0064] FIG. 9 is an explanatory diagram illustrating a cross-sectional image (modification) of the SIP board 6. The signal layer 81 is not limited to being configured on the top layer on which electrical components (semiconductor elements) such as the communication unit 61 or the processing unit 62 are mounted, but may be configured on, for example, the bottom layer. In this case, the communication unit 61 mounted on the top layer and the pattern or land formed on the signal layer 81 may be connected (conductive) by through holes that penetrate the SIP board 6 in the stacking direction. The connector-side layer 82 and the circuit-side layer 83 may also be configured on either layer. In this case, the connector-side layer 82 and the circuit-side layer 83 may be configured on the same layer or on different layers.

[0065] (Embodiment 2) Fig. 10 is an explanatory diagram illustrating an SIP board 6 including terminals using LGA according to embodiment 2. Fig. 11 is an explanatory diagram illustrating a connector side layer 82 (connector side solid GND layer). Fig. 12 is an explanatory diagram illustrating a signal layer 81. Fig. 13 is an explanatory diagram illustrating a board cross-section image of the SIP board 6. In this embodiment, the terminals used to connect the SIP board 6 and the main board 2 are configured as LGA (Land Grid Array). Alternatively, the terminals used to connect the SIP board 6 and the main board 2 may be BGA (Ball Grid Array) or PGA (Ping Grid Array).

[0066] When the terminals for connecting the SIP board 6 and the main board 2 are configured using LGA, a plurality of square lands are arranged in a grid pattern on the back surface (bottom surface) of the lowest layer of the SIP board 6. In this case, as in the first embodiment, signal terminals (LIN signal terminals 811, CAN signal terminals 812, and Ethernet signal terminals 813) connected to the signal layer 81 and connector-side terminals (CAN connector-side terminals 822 and Ethernet connector-side terminals 823) connected to the connector-side layer 82 may be arranged on one peripheral edge (end), and circuit-side terminals 831 connected to the circuit-side layer 83 may be arranged on the other peripheral edge (end). The hierarchical structure including the signal layer 81 and solid GND layers (connector-side layer 82 and circuit-side layer 83) is the same as in the first embodiment, and patterns formed on each layer and the terminals configured using LGA are connected (conductive) via, for example, through holes.

[0067] The embodiments disclosed herein are to be considered as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0068] Multiple claims may be combined with each other regardless of the form of reference. The claims may contain multiple dependent claims that depend on multiple claims. Multiple dependent claims may be contained that depend on multiple dependent claims. If multiple dependent claims that depend on multiple dependent claims are not contained, this does not limit the number of multiple dependent claims that depend on multiple dependent claims.

[0069] DESCRIPTION OF SYMBOLS C Vehicle 1 In-vehicle device 2 Main board 201 Communication line 202 Electric wire 21 Power supply circuit 22 Second processing unit (microcomputer) 23 Second Ethernet connector 24 Second Ethernet connection element 25 Second Ethernet PHY unit 3 Connector side conductor (connector GND) 32 CAN side conductor (CN1 side GND) 33 Ethernet side conductor (CN2 side GND) 301 Suppressor 4 Circuit side conductor (circuit GND) 5 Connector 50 Power supply connector 51 LIN connector 52 CAN connector 53 Ethernet connector 6 SIP board 61 Communication unit 611 LIN transceiver 612 CAN transceiver 613 Ethernet PHY unit 62 Processing unit 63 Connection element 630 Power supply connection element 631 LIN connection element 632 CAN connection element 633 Ethernet connection element 72 CAN termination resistor 73 Ethernet termination resistor 81 Signal layer 811 LIN signal terminal 812 CAN signal terminal 813 Ethernet signal terminal 82 Connector side layer 822 CAN connector side terminal 823 Ethernet connector side terminal 83 Circuit side layer 831 Circuit side terminal 91 In-vehicle ECU 92 Power supply device

Claims

1. An on-board device that performs processing related to communication between on-board ECUs mounted on a vehicle, comprising: a connector to which the on-board ECU is connected; a power supply circuit to which power is supplied from a power supply device mounted on the vehicle; a connector-side conductor connected to the connector and determining a reference potential on the connector side; a circuit-side conductor connected to the power supply circuit and determining a reference potential on the power supply circuit side; and a SIP (System in Package) board connected to the connector-side conductor and the circuit-side conductor, wherein the SIP board includes: a communication unit connected to the connector; a processing unit connected to the communication unit and performing processing related to communication between the on-board ECUs; and a connecting element interposed between the connector and the communication unit, wherein the processing unit and the communication unit are connected to the circuit-side conductor.

2. The in-vehicle device according to claim 1, wherein the connection element includes a common mode choke coil or inductor, and is interposed between the connector-side conductor and the circuit-side conductor, and separates the connector-side conductor from the circuit-side conductor by preventing fluctuations in reference potential occurring on either side from affecting the reference potential of the other side.

3. The in-vehicle device according to claim 2, wherein the communication unit includes a CAN transceiver whose communication protocol is CAN and an Ethernet PHY unit that is compliant with Ethernet; the connector side conductor includes a CAN side conductor to which the CAN transceiver is connected via the connection element, and an Ethernet side conductor to which the Ethernet PHY unit is connected via the connection element; the CAN side conductor and the Ethernet side conductor are separated; the connection elements include an Ethernet connection element connected to the Ethernet PHY unit and a CAN connection element connected to the CAN transceiver; and the Ethernet connection element and the CAN connection element are common mode choke coils.

4. The in-vehicle device according to claim 3, wherein the communication unit includes a LIN transceiver whose communication protocol is LIN, the LIN transceiver is connected to the CAN side conductor via the connection element, and the connection element connected to the LIN transceiver is an inductor.

5. The in-vehicle device according to claim 3, wherein the connector includes an Ethernet connector and a CAN connector, and the SIP board includes an Ethernet termination resistor interposed between the Ethernet connector and the Ethernet connection element, and a CAN termination resistor interposed between the CAN connector and the CAN connection element, the Ethernet termination resistor being connected to the Ethernet side conductor, and the CAN termination resistor being connected to the CAN side conductor.

6. The in-vehicle device according to claim 1, further comprising a main board on which the SIP board is detachably mounted, and the connector and the power supply circuit are mounted on the main board.

7. The in-vehicle device according to claim 6, wherein the SIP board includes a signal layer connected to the connector, a connector-side layer connected to the connector-side conductors, and a circuit-side layer connected to the circuit-side conductors.

8. The in-vehicle device according to claim 7, wherein the SIP board has a plurality of terminals connected to the main board, the plurality of terminals including signal terminals connected to the signal layer, connector-side terminals connected to the connector-side layer, and circuit-side terminals connected to the circuit-side layer, the signal terminals and the connector-side terminals being arranged on the same peripheral portion of the SIP board, and the circuit-side terminals being arranged on a peripheral portion different from the peripheral portions on which the signal terminals and the connector-side terminals are arranged.

9. The in-vehicle device according to claim 7, wherein the width of the pattern formed on the connector side layer is wider than the width of the pattern formed on the signal layer.

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