Relay control device, control system, control method, and computer program

Abstract

The relay control device is mounted in a vehicle and includes a control unit that switches, for each of a plurality of relay circuits connected to each of a plurality of ECUs, between a relay-on state in which power is supplied to the ECUs and a relay-off state in which power is not supplied to the ECUs, the plurality of ECUs including: a first ECU; a transition function for transitioning the operation state of the vehicle between at least two of a normal state, a dormant state, and a power-off state in accordance with the power state of the vehicle; and a second ECU that does not have the transition function, the control unit performing a switching control of switching the second ECU from the relay-on state to the relay-off state in accordance with a change in the power supply state, and switching the second ECU from the relay-on state to the relay-off state in accordance with a change in the power supply state. A first relay circuit connected to the first ECU among the plurality of relay circuits is maintained in the relay ON state, and a second relay circuit connected to the second ECU among the plurality of relay circuits is switched to the relay OFF state.

Description

Technical Field

[0001] The present disclosure relates to a relay control device, a control system, a control method, and a computer program. This application claims priority based on Japanese application No. 2022-083648 filed on May 23, 2022, and all the contents described in the above Japanese application are cited. Background Art

[0002] There is known a relay control device that supplies and cuts off electric power to an ECU (Electronic Control Unit) or an actuator mounted on a vehicle.

[0003] For example, Patent Document 1 discloses a technology in which a relay control device performs processing to turn off a relay device when an ignition switch is operated from on to off. Prior art literature Patent Literature

[0004] Patent document 1: Japanese Patent Application Publication No. 2018-053979. Summary of the invention

[0005] The relay control device disclosed herein is a relay control device mounted on a vehicle, comprising a control unit, which switches between a relay-on state in which power is supplied to a plurality of ECUs respectively connected to the plurality of ECUs and a relay-off state in which power is not supplied to the ECUs, the plurality of ECUs comprising: a first ECU having a transition function for transitioning its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; and a second ECU not having the transition function, the control unit performing the following switching control: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is to be switched from the relay-on state to the relay-off state as the power state changes, a second relay circuit in the plurality of relay circuits connected to the second ECU is switched to the relay-off state while a first relay circuit in the plurality of relay circuits connected to the first ECU is maintained in the relay-on state.

[0006] The control method disclosed herein is a control method for controlling a plurality of relay circuits respectively connected to a plurality of ECUs by means of a relay control device mounted on a vehicle, wherein the plurality of ECUs include: a first ECU having a transition function for transitioning its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; and a second ECU not having the transition function, wherein the control method includes: a switching step for switching the plurality of relay circuits respectively between a relay-on state in which power is supplied to the ECUs and a relay-off state in which power is not supplied to the ECUs, the switching step including the following steps: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is switched from the relay-on state to the relay-off state as the power state changes, while a first relay circuit connected to the first ECU among the plurality of relay circuits is maintained in the relay-on state, a second relay circuit connected to the second ECU among the plurality of relay circuits is switched to the relay-off state.

[0007] The computer program disclosed herein is a computer program for controlling a plurality of relay circuits respectively connected to a plurality of ECUs by means of a relay control device mounted on a vehicle, the plurality of ECUs including: a first ECU having a transition function for transitioning its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; and a second ECU not having the transition function, the computer program causing a computer to execute a switching step for switching the plurality of relay circuits respectively between a relay-on state in which power is supplied to the ECUs and a relay-off state in which power is not supplied to the ECUs, the switching step including the following steps: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is to be switched from the relay-on state to the relay-off state as the power state changes, switching a second relay circuit connected to the second ECU among the plurality of relay circuits to the relay-off state while maintaining a first relay circuit connected to the first ECU in the relay-on state. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a diagram showing an example of a control system according to the embodiment.

[0009] Figure 2 It is a diagram for explaining the subject of the embodiment.

[0010] Figure 3 This is a flowchart showing an example of a control method according to the embodiment.

[0011] Figure 4 : is a flowchart showing a control method according to a modification example.

[0012] Figure 5 It is a diagram showing a control system according to a modification example.

[0013] Figure 6 It is a diagram showing a control system according to a modification example.

[0014] Figure 7 : is a flowchart showing a control method according to a modification example. DETAILED DESCRIPTION Problems to be Solved by the Present Disclosure

[0015] Some ECUs have a function (transition function) to change their operating state according to the state of the ignition switch. For example, in such ECUs, when the ignition switch is turned from OFF to ON, the ECU automatically wakes up, and when the ignition switch is turned from ON to OFF, the ECU automatically goes to sleep.

[0016] When the relay control device supplies and cuts off power to an ECU having a switching function, if the relay control device cuts off power to the ECU while the ECU is switching its own operating state, a malfunction may occur in the ECU.

[0017] In view of the above problems, an object of the present disclosure is to provide a relay control device, a control system, a control method, and a computer program capable of suppressing the occurrence of a malfunction in an ECU that controls the supply and cutoff of electric power by the relay control device. Effects of the present disclosure

[0018] According to the present disclosure, it is possible to suppress the occurrence of a malfunction in the ECU in which the supply and cutoff of electric power are controlled by the relay control device. [Description of Embodiments of the Present Disclosure]

[0019] The embodiments of the present disclosure include the following structures as the gist thereof.

[0020] (1) A relay control device disclosed herein is a relay control device mounted on a vehicle, comprising a control unit that switches, for a plurality of relay circuits connected to a plurality of ECUs, between a relay-on state in which power is supplied to the ECUs and a relay-off state in which power is not supplied to the ECUs, the plurality of ECUs comprising: a first ECU having a transition function for transitioning its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; and a second ECU not having the transition function, the control unit performing the following switching control: when the plurality of relay circuits are in the relay-on state, when the second ECU is switched from the relay-on state to the relay-off state in accordance with a change in the power state, the control unit switches a second relay circuit connected to the second ECU to the relay-off state while maintaining a first relay circuit connected to the first ECU in the relay-on state.

[0021] With this configuration, the power supply to the first ECU is maintained after the switching control, so that it is possible to avoid forced interruption of the power supply when the first ECU changes its operating state. This can suppress the occurrence of malfunctions in the first ECU.

[0022] (2) When the first relay circuit is in the relay-on state, the first ECU may transmit predetermined information indicating that the first ECU has the transition function to the relay control device, and the control unit may execute the switching control based on the predetermined information.

[0023] Furthermore, the relay control device may hold the predetermined information, and the control unit may execute the switching control based on the information.

[0024] With this configuration, the control unit can understand the first relay circuit connected to the first ECU based on predetermined information.

[0025] (3) Alternatively, in the relay control device of (2) above, after executing the switching control, the control unit may maintain the first relay circuit in the relay-on state if the relay control device receives a communication message for detecting communication with the first ECU at intervals within a prescribed time; and after executing the switching control, if the relay control device does not receive the communication message within the prescribed time, the control unit may switch the first relay circuit to the relay-off state.

[0026] This can suppress the occurrence of a malfunction in the first ECU, and can also place the first relay circuit in the relay-off state, thereby suppressing power consumption in the control system.

[0027] (4) In the relay control device of (2) or (3) above, the predetermined information may include information requesting notification of the power supply state to the first ECU. This can reduce the control load in the control system.

[0028] (5) In the relay control device according to any one of (2) to (4) above, the control unit may determine the first ECU from among the plurality of ECUs or determine the first relay circuit from among the plurality of relay circuits based on the predetermined information.

[0029] (6) The relay control device according to any one of (1) to (5) may be directly connected to a relay circuit provided outside the relay control device among the plurality of relay circuits via a power line or connected via another device.

[0030] (7) In the relay control device according to any one of (1) to (6) above, at least one of the plurality of relay circuits may be provided inside the relay control device.

[0031] (8) A control system of the present disclosure includes: the relay control device according to any one of (1) to (7) above; a plurality of ECUs including the first ECU; and a plurality of relay circuits including the first relay circuit.

[0032] (9) The control method disclosed herein is a control method for controlling a plurality of relay circuits respectively connected to a plurality of ECUs by means of a relay control device mounted on a vehicle, wherein the plurality of ECUs include: a first ECU having a transition function for transitioning its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; and a second ECU not having the transition function, wherein the control method comprises: a switching step for switching the plurality of relay circuits respectively between a relay-on state in which power is supplied to the ECUs and a relay-off state in which power is not supplied to the ECUs, the switching step comprising the following steps: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is to be switched from the relay-on state to the relay-off state as the power state changes, while a first relay circuit connected to the first ECU among the plurality of relay circuits is maintained in the relay-on state, a second relay circuit connected to the second ECU among the plurality of relay circuits is switched to the relay-off state.

[0033] By configuring in this way, after the step of switching the relay circuit other than the first relay circuit, i.e., the second relay circuit, to the relay-off state, the power supply to the first ECU is maintained, thereby avoiding forced cutting off of the power supply in the middle of the first ECU changing the operating state. Thus, the occurrence of an adverse situation in the first ECU can be suppressed.

[0034] (10) The computer program disclosed herein is a computer program for controlling a plurality of relay circuits respectively connected to a plurality of ECUs by means of a relay control device mounted on a vehicle, the plurality of ECUs comprising: a first ECU having a transition function for transitioning its own operating state between at least two states of a normal state, a sleep state and a power-off state according to a power state of the vehicle; and a second ECU not having the transition function, the computer program causing a computer to execute a switching step for switching the plurality of relay circuits respectively between a relay-on state in which power is supplied to the ECUs and a relay-off state in which power is not supplied to the ECUs, the switching step comprising the following steps: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is to be switched from the relay-on state to the relay-off state as the power state changes, while a first relay circuit connected to the first ECU among the plurality of relay circuits is maintained in the relay-on state, a second relay circuit connected to the second ECU among the plurality of relay circuits is switched to the relay-off state.

[0035] By configuring in this way, after the step of switching the relay circuit other than the first relay circuit, i.e., the second relay circuit, to the relay-off state, the power supply to the first ECU is maintained, thereby avoiding forced cutting off of the power supply in the middle of the first ECU changing the operating state. Thus, the occurrence of an adverse situation in the first ECU can be suppressed. 1. Details of the embodiments of the present disclosure

[0036] Hereinafter, details of the embodiments of the present disclosure will be described with reference to the drawings. 1.1 Structure of the control system

[0037] Figure 1 1 is a diagram showing a configuration example of a control system 1 according to an embodiment. Figure 1 In the figure, thin lines connecting the various parts of the control system 1 represent communication lines, and thick lines connecting the various parts of the control system 1 represent power lines. Figure 5 as well as Figure 6 ) is also manifested in the same way.

[0038] The control system 1 is a system mounted on a vehicle V1 such as an automobile. The control system 1 includes a relay control device 10, a plurality of ECUs (Electronic Control Units) 20, a plurality of relay circuits 30, a plurality of power lines 40, and a plurality of communication lines 50. The vehicle V1 is also equipped with a power supply device 60, an ignition switch 71, and a power supply control ECU 72.

[0039] The power supply device 60 supplies power to various parts of the vehicle V1. The power supply device 60 includes a battery 61 used in normal use and an auxiliary battery 62 used as an auxiliary when the power of the battery 61 is insufficient. The auxiliary battery 62 is, for example, an uninterruptible power supply (UPS).

[0040] The ignition switch 71 is a switch that switches the power state of the vehicle V1 when, for example, the passenger of the vehicle V1 inserts a key and turns it. The ignition switch 71 may also be operated by the passenger of the vehicle V1 carrying an electronic key and pressing the switch without inserting the key. The ignition switch 71 switches the power state of the vehicle V1 to a vehicle power off state, an accessory on state (ACC on state), an ignition on state (IG on state), and an engine start state each time the ignition switch 71 is operated.

[0041] The vehicle power off state, ACC on state, and IG on state are in this order, and the range of power supply from the power supply device 60 to each part of the vehicle V1 becomes wider. The vehicle power off state is, for example, a state in which power is not supplied from the power supply device 60 to each part of the vehicle V1 including the accessory electrical components described later, except for the normal power supply. The ACC on state is, for example, a state in which power is supplied from the power supply device 60 to the accessory electrical components (for example, an audio device, a navigation device, etc.) mounted on the vehicle V1, but power is not supplied to other parts. The IG on state is, for example, a state in which power is supplied from the power supply device 60 to each part of the vehicle V1 except for the starter motor (starter). The engine start state is, for example, a state in which power is supplied from the power supply device 60 to the starter motor.

[0042] The power supply control ECU 72 is connected to the ignition switch 71 via the communication line 54. The power supply control ECU 72 obtains information (power supply information D1) on the power supply state of the vehicle V1 based on a signal transmitted from the ignition switch 71 via the communication line 54. The power supply control ECU 72 transmits the power supply information D1 to the relay control device 10 via the communication line 53.

[0043] The relay control device 10 is a device that controls each of the plurality of relay circuits 30. The relay control device 10 includes a microcomputer (microcomputer) 11 including a control unit 12 and a storage unit 13, and a reading unit 14.

[0044] The control unit 12 includes, for example, a circuit structure such as a processor. Specifically, the control unit 12 includes one or more CPUs (Central Processing Units). The processor included in the control unit 12 may also be a GPU (Graphics Processing Unit). In this case, the control unit 12 reads a computer program stored in the storage unit 13 and performs various operations and controls.

[0045] The control unit 12 may also include a processor in which a predetermined program is pre-written. For example, the control unit 12 may be an integrated circuit such as a CPLD (complex programmable logic device), an FPGA (field programmable gate array), or an ASIC (application-specific integrated circuit). In this case, the control unit 12 performs various operations and controls based on the pre-written program.

[0046] The storage unit 13 has a volatile memory and a nonvolatile memory, and stores various data. The volatile memory includes, for example, a RAM (Random Access Memory). The nonvolatile memory includes, for example, a flash memory, a HDD (Hard Disk Drive), an SSD (Solid State Drive), or a ROM (Read Only Memory). The storage unit 13 stores, for example, a computer program and various parameters in the nonvolatile memory.

[0047] The reading unit 14 reads information from a computer-readable recording medium 15. The recording medium 15 is, for example, an optical disk such as a CD or a DVD or a USB flash memory. The reading unit 14 is, for example, an optical drive or a USB terminal. The recording medium 15 records a computer program and various parameters, and by causing the reading unit 14 to read the recording medium 15, the computer program and various parameters are stored in the nonvolatile memory of the storage unit 13.

[0048] The ECU 20 is, for example, a device that controls various components of the vehicle V1 (e.g., brakes, doors, battery, air conditioning, etc.) (operation system ECU). The function of the ECU 20 is not particularly limited, and the ECU 20 may also be a device that monitors the status of various components of the vehicle V1 by communicating with sensors (recognition system ECU).

[0049] The plurality of ECUs 20 may have different functions or the same functions. In addition, the number of the plurality of ECUs 20 is not particularly limited. Figure 1 Two ECUs 20 are shown in the figure, but three or more ECUs 20 may be provided in the control system 1 , or one ECU 20 may be provided.

[0050] The plurality of ECUs 20 include a first ECU 21 and a second ECU 22. The first ECU 21 has a transition function of transitioning its own operating state according to the power state of the vehicle V1. The operating state of the first ECU 21 includes, for example, a normal state, a sleep state, and a power-off state.

[0051] The normal state is a state in which the first ECU 21 is awakened and the functions of the first ECU 21 required for various controls can be used. For example, the normal state is a state in which a clock circuit of a processor included in the first ECU 21 operates at a predetermined number of clocks set in advance.

[0052] The sleep state is a state in which the functions of the first ECU 21 are limited compared to the normal state to suppress power consumption. For example, the sleep state is a state in which the operation of the clock circuit and the operation of the processor are stopped by stopping the power supply to the clock circuit of the processor included in the first ECU 21. In addition, the sleep state may be a state in which the clock circuit of the processor included in the first ECU 21 is supplied with power but the power consumption is suppressed by operating with a clock number less than the clock number in the normal state.

[0053] The power-off state is a state in which the functions of the first ECU 21 are limited to suppress power consumption compared to the sleep state. For example, the power-off state is a state in which power is supplied only to the circuits that are minimally required to make the first ECU 21 transition to the sleep state or the normal state, and power supply to other circuits is stopped. The power-off state may be a state in which power supply to all circuits included in the first ECU 21 is stopped.

[0054] When the power state of the vehicle V1 is switched from other states to the vehicle power off state, the first ECU 21 is switched to the power off state. In addition, when the power state of the vehicle V1 is switched from other states to the ACC on state, the first ECU 21 is switched to the sleep state. In addition, when the power state of the vehicle V1 is switched from other states to the IG on state, the first ECU 21 is switched to the normal state.

[0055] That is, the first ECU 21 transitions the operating state as follows according to the power supply state of the vehicle V1.

[0056] <Example of Correspondence between the Power Supply State of the Vehicle V1 and the Operating State of the First ECU 21> Vehicle power disconnect status: Power disconnect status ACC on state: Sleep state IG connection status: Normal status

[0057] In addition, the above correspondence is an example, and the first ECU 21 can be in a dormant state when the vehicle power is off, in a normal state when the ACC is on, or in a power-off state when the ACC is on. In addition, the first ECU 21 can also be in a dormant state when the IG is on. In this case, after the first ECU 21 is in a dormant state, it switches to a normal state as needed. That is, the first ECU 21 changes its own operating state between at least two states of the normal state, the dormant state, and the power-off state according to the power state of the vehicle V1.

[0058] The second ECU 22 is an ECU that does not have a conversion function. That is, all of the ECUs other than the first ECU 21 among the plurality of ECUs 20 are the second ECU 22 .

[0059] The plurality of relay circuits 30 are connected one-to-one with the plurality of ECUs 20. The correspondence between the plurality of relay circuits 30 and the plurality of ECUs 20 is stored in the storage unit 13 in a table format, for example. Therefore, the relay control device 10 understands which ECU 20 is connected to which relay circuit 30.

[0060] When the plurality of relay circuits 30 are particularly distinguished, the relay circuit 30 connected to the first ECU 21 is referred to as a “first relay circuit 31”, and the relay circuit 30 connected to the second ECU 22 is referred to as a “second relay circuit 32”. All ECUs other than the first ECU 21 among the plurality of ECUs 20 are second ECUs 22, and therefore all relay circuits other than the first relay circuit 31 among the plurality of relay circuits 30 are second relay circuits 32.

[0061] The relay circuit 30 is, for example, a mechanical relay including contacts and a coil, and the contacts are opened and closed by mechanical action. Alternatively, the relay circuit 30 may be a semiconductor relay that performs relaying by a semiconductor element. For example, the semiconductor relay is a MOSFET (metal-oxide-semiconductorfield-effect-transistor) relay.

[0062] The relay circuit 30 switches between a relay-on state and a relay-off state according to a control signal CS1 output from the control unit 12 of the relay control device 10. The relay-on state is a state in which the contacts are closed (or the gate of the MOSFET is turned on) to supply power to the ECU 20. Figure 1 In the example of , the first relay circuit 31 is in the relay-on state. The relay-off state is a state in which the contacts are disconnected (or the gate of the MOSFET is turned off) and power is not supplied to the ECU 20. Figure 1In the example of , the second relay circuit 32 is in the relay-off state.

[0063] In the case of special distinction, the plurality of power lines 40 are respectively referred to as power lines 41, 42, 43, and 44. The power line 40 is a line for transmitting power supplied from the power supply device 60. The power line 41 connects the relay control device 10 to the first ECU 21 via the first relay circuit 31. The power line 42 connects the relay control device 10 to the second ECU 22 via the second relay circuit 32. That is, the relay control device 10 is directly connected to the relay circuit 30 provided outside the relay control device 10 through the power lines 41 and 42. The power line 43 connects the relay control device 10 to the power supply device 60. The power line 44 connects the power supply control ECU 72 to the power supply device 60.

[0064] When particularly distinguished, the plurality of communication lines 50 are respectively referred to as communication lines 51, 52, 53, and 54. The communication lines 50 transmit signals sent and received between devices connected via the communication lines 50 according to a predetermined communication protocol. Examples of the predetermined communication protocol are CAN (Controller Area Network), CAN-FD (CAN with Flexible Data Rate), or Ethernet (registered trademark).

[0065] The communication line 51 connects the relay control device 10 and the first ECU 21. The communication line 52 connects the relay control device 10 and the second ECU 22. The communication line 53 connects the relay control device 10 and the power supply control ECU 72. The communication line 54 connects the ignition switch 71 and the power supply control ECU 72. 1.2 Issues to be Solved by the Present Embodiment

[0066] Figure 2 1 is a diagram for explaining the subject of the implementation method. Figure 2 In the figure, the process of power transmission is shown with a thick line, and the process of signal transmission is shown with a thin line. Figure 3 , Figure 4 as well as Figure 7 ) is also manifested in the same way.

[0067] When the relay control device 10 supplies and cuts off the power to the first ECU 21 (ECU 20 having a switching function) by controlling the relay circuit 31, if the relay control device 10 cuts off the power to the first ECU 21 while the first ECU 21 is switching its own operating state, a malfunction may occur in the first ECU 21. Figure 1 and Figure 2 Describe the situation.

[0068] First, the vehicle V1 is in the vehicle power off state, and the plurality of relay circuits 30 are all in the relay off state. Therefore, none of the plurality of ECUs 20 is supplied with power from the power supply device 60, and all of the plurality of ECUs 20 are in the power off state.

[0069] The relay control device 10 and the power supply control ECU 72 are supplied with electric power from the power supply device 60 via the power lines 43 and 44 regardless of the power supply state of the vehicle V1 (constant power supply: steps S101 and S102 ).

[0070] When the ignition switch 71 is operated and the power state of the vehicle V1 becomes the IG-on state (step S201), the power control ECU 72 sends the power information D1 indicating that the power state of the vehicle V1 is the IG-on state to the relay control device 10 via the communication line 53 (step S301). In addition, step S201 may also be a step of switching from the vehicle power-off state to the ACC-on state. In this case, in step S301, the power control ECU 72 sends the power information D1 indicating that the power state of the vehicle V1 is the ACC-on state to the relay control device 10 via the communication line 53.

[0071] The relay control device 10 switches the plurality of relay circuits 30 from the relay-off state to the relay-on state, respectively, based on the power supply information D1 (step S302). Specifically, the control unit 12 outputs the control signal CS1 based on the power supply information D1. Furthermore, the plurality of relay circuits 30 switches from the relay-off state to the relay-on state, respectively, based on the control signal CS1. Thus, power is supplied to the first ECU 21 and the second ECU 22 (steps S303 and S304).

[0072] When receiving power supply, the first ECU 21 changes the operation state from the power-off state to the normal state (or the sleep state) (transition start processing: step S305 ). The transition start processing of the first ECU 21 in step S305 is also referred to as “startup processing”.

[0073] After the start-up process, the first ECU 21 transmits a request message D2 for requesting notification of the power information D1 to the power control ECU 72 in order to exert its own conversion function (steps S306, S307). Specifically, the request message D2 is transmitted from the first ECU 21 to the relay control device 10 via the communication line 51 (step S306), and then transmitted from the relay control device 10 to the power control ECU 72 via the communication line 53 (step S307).

[0074] The power control ECU 72 that receives the request information D2 sends the power information D1 to the first ECU 21 (steps S309 and S310). Specifically, after the power control ECU 72 sends the power information D1 to the relay control device 10 via the communication line 53 (step S309), the power information D1 is sent from the relay control device 10 to the first ECU 21 via the communication line 51 (step S310). The power control ECU 72 may send the power information D1 to the first ECU 21 periodically, or may send the power information D1 to the first ECU 21 when the power state of the vehicle V1 is changed.

[0075] When the ignition switch 71 is operated and the power state of the vehicle V1 changes from the IG on state to the vehicle power off state (or the ACC on state) (step S202), the power control ECU 72 sends power information D1 indicating that the power state of the vehicle V1 is the vehicle power off state (or the ACC on state) to the relay control device 10 via the communication line 53 (step S401).

[0076] The relay control device 10 transmits the received power supply information D1 to the first ECU 21 via the communication line 51 (step S402). As a result, the first ECU 21 changes the operating state from the normal state to the power off state (or sleep state) (transition end processing: step S403). The transition end processing of the first ECU 21 in step S403 is also called "stop processing".

[0077] In addition, when the first ECU 21 is in the sleep state at the start time of step S403, such as when the first ECU 21 is in the sleep state in step S305, the first ECU 21 may change the operation state from the sleep state to the power-off state in step S403.

[0078] The relay control device 10 switches the plurality of relay circuits 30 from the relay-on state to the relay-off state based on the power supply information D1 (step S901). Specifically, the control unit 12 outputs the control signal CS1 based on the power supply information D1. Furthermore, the plurality of relay circuits 30 switch from the relay-on state to the relay-off state based on the control signal CS1. As a result, the power supply to the first ECU 21 and the second ECU 22 is cut off (steps S902, S405).

[0079] Here, during the process of the first ECU 21 executing the stop process (step S403), the first relay circuit 31 sometimes becomes a relay-off state (step S901), and the power supply to the first ECU 21 via the power line 41 is cut off (step S902). When the power supply to the first ECU 21 is cut off, the first ECU 21 is forcibly (passively) turned into a power-off state.

[0080] During the stop process, for example, a process is performed to write the history and parameters of various processes executed by the first ECU 21 to the nonvolatile memory included in the first ECU 21. If the power supply to the first ECU 21 is cut off during the stop process, the history of the processes may not be saved, and the changes in the parameters may not be saved.

[0081] The control system 1 is, for example, a system installed after the system already installed in the vehicle V1 (an extended system). The plurality of ECUs 20 included in the control system 1 differ depending on the content of the extension. That is, the plurality of ECUs 20 may all be the first ECUs 21 or all be the second ECUs 22.

[0082] The relay control device 10 cannot know at the time of connection whether the ECU 20 connected to itself is the first ECU 21 or the second ECU 22. Therefore, the relay control device 10 sets all relay circuits 30 to the relay-off state in step S901, which may result in the above-mentioned inconvenience.

[0083] Therefore, the relay control device 10 (specifically, the control unit 12) of the present embodiment determines the first ECU 21 from the plurality of ECUs 20 based on the prescribed information (for example, the request information D2) transmitted from the first ECU 21 to the relay control device 10. And, instead of step S901, the relay control device 10 (control unit 12) performs the following switching control: while the first relay circuit 31 is maintained in the relay-on state, the second relay circuit 32 is switched to the relay-off state.

[0084] This can avoid forced interruption of the power supply in the first ECU 21, and thus can suppress the occurrence of a malfunction in the first ECU 21. Hereinafter, a control method in the control system 1 will be described in detail. 1.3 Control methods

[0085] Figure 3 It is a flowchart showing an example of a control method executed by the control system 1 . Figure 3 Among the controls shown, the control performed by the relay control device 10 is realized by the control unit 12 reading a computer program from the storage unit 13 (or executing various calculations and processes in accordance with a program written in advance in the control unit 12 ). Figure 3 The order of the steps shown can also be adjusted appropriately. Figure 3 In the control method, Figure 2 The same reference numerals are used for the common steps, and the description thereof will be appropriately omitted.

[0086] The control system 1 executes the following steps until step S307. Figure 2The same process. That is, after the power state of the vehicle V1 is changed from the vehicle power off state to the IG on state (step S201), the relay control device 10 makes the plurality of relay circuits 30 respectively become the relay on state based on the power information D1 received from the power control ECU 72 (step S302). As a result, power is supplied to the first ECU 21 and the second ECU 22 (steps S303 and S304), and the first ECU 21 performs the startup process (step S305).

[0087] After the start-up process, the first ECU 21 transmits the request information D2 to the power supply control ECU 72 via the relay control device 10 in order to exert its own transition function (steps S306 and S307 ).

[0088] Here, the control unit 12 of the relay control device 10 determines the first ECU 21 from the plurality of ECUs 20 based on the request information D2 received in step S306 (determination process: step S308). The request information D2 is information for requesting notification of the power supply information D1, so it can be determined that the ECU 20 making such a request is an ECU having a conversion function (i.e., the first ECU 21). Therefore, when the control unit 12 receives the request information D2, it stores the ECU 20 of the request source included in the request information D2 as the first ECU 21 in the storage unit 13.

[0089] Through the determination process, the control unit 12 can grasp which ECU 20 among the plurality of ECUs 20 is the first ECU 21. In addition, the request information D2 is information that the first ECU 21 sends to the power supply control ECU 72 in order to exert its own conversion function. Therefore, the first ECU 21 does not need to generate and send additional information in order to notify the control unit 12 that it has the conversion function. Therefore, by the control unit 12 determining the first ECU 21 based on the request information D2, the control load in the control system 1 can be reduced.

[0090] When the plurality of ECUs 20 include the plurality of first ECUs 21 , the plurality of first ECUs 21 transmit request information D2 (step S306 ). The control unit 12 determines the plurality of first ECUs 21 from the plurality of ECUs 20 based on each of the plurality of request information D2 received.

[0091] The power control ECU 72 that has received the request information D2 sends the power information D1 to the first ECU 21 (steps S309, S310). After the power state of the vehicle V1 is changed from the IG on state to the vehicle power off state (or the ACC on state) (step S202), the relay control device 10 sends the power information D1 received from the power control ECU 72 in step S401 to the first ECU 21 (step S402). Based on the received power information D1, the first ECU 21 performs a stop process (step S403).

[0092] Based on the power supply information D1 and the determination result of the determination process (step S308), the control unit 12 maintains the first relay circuit 31 in the relay-on state and switches the relay circuits other than the first relay circuit 31 (i.e., the second relay circuit 32) among the plurality of relay circuits 30 to the relay-off state (switching control: step S404).

[0093] The control unit 12 determines the first ECU 21 from the plurality of ECUs 20 through the determination process (step S308). In addition, the storage unit 13 stores the correspondence between the plurality of relay circuits 30 and the plurality of ECUs 20. Therefore, the control unit 12 can determine the first relay circuit 31 and the second relay circuit 32 from the plurality of relay circuits 30 by determining the first ECU 21.

[0094] Then, the control unit 12 switches the second relay circuit 32 to the relay-off state by outputting a control signal CS1 for switching from the relay-on state to the relay-off state to the second relay circuit 32. As a result, the power supply to the second ECU 22 is cut off (step S405).

[0095] At this time, the control unit 12 does not output the control signal CS1 for switching from the relay-on state to the relay-off state to the first relay circuit 31. Therefore, the control unit 12 can maintain the first relay circuit 31 in the relay-on state. As a result, the power supply to the first ECU 21 is maintained, so that the forced cutoff of the power supply during the stop process of the first ECU 21 can be avoided. As a result, the occurrence of adverse conditions in the first ECU 21 can be suppressed. 2. Modifications

[0096] Hereinafter, a modification of the embodiment will be described. In the modification, the same reference numerals are given to the same components as those of the above-described embodiment, and description thereof will be omitted. 2.1 NM communication between ECU and relay control device

[0097] In the above-mentioned embodiment, the relay control device 10 maintains the first relay circuit 31 connected to the first ECU 21 in the relay-on state. However, the relay control device 10 may switch the first relay circuit 31 to the relay-off state after the stop process in the first ECU 21 is completed. Thus, the first ECU 21 can be electrically disconnected from the power supply device 60, so that the power consumption in the control system 1 can be suppressed.

[0098] The method by which the relay control device 10 determines that the stop processing in the first ECU 21 has ended is not particularly limited. For example, in the case where the relay control device 10 performs network management communication (hereinafter referred to as "NM communication") with the first ECU 21, when a communication message accompanying the NM communication is not received by the relay control device 10 for more than a prescribed time (i.e., when the NM communication is stopped), it can be determined that the stop processing in the first ECU 21 has ended.

[0099] Figure 4 is a flowchart showing a control method according to a modified example. The control system 1 executes the following steps until step S310. Figure 3 Same treatment. Figure 4 , the processing from step S101 to step S304 is omitted.

[0100] exist Figure 4 In the example of , the relay control device 10 performs NM communication with the first ECU 21. When the normal state is reached through the startup process (step S305), the first ECU 21 sends a communication message M1 to the relay control device 10 via the communication line 51 at intervals of a predetermined time T1 (steps S501, S503, S505, etc.). The communication message M1 is a message for detecting whether there is mutual communication between the relay control device 10 and the first ECU 21.

[0101] In response to receiving the communication message M1 from the first ECU 21 (or independently), the relay control device 10 sends the communication message M1 to the first ECU 21 via the communication line 51 at a predetermined interval within a predetermined time T1 (steps S502, S504, S506, ...). In this way, the relay control device 10 and the first ECU 21 detect mutual communication by sending and receiving the communication message M1 to each other.

[0102] That is, the relay control device 10 detects that the operation state of the first ECU 21 is normal while receiving the communication message M1 at the predetermined interval within the predetermined time T1. The first ECU 21 detects that the operation state of the relay control device 10 is normal while receiving the communication message M1 at the predetermined interval.

[0103] After the power state of the vehicle V1 changes from the IG ON state to the vehicle power OFF state (or the ACC ON state) (step S202 ), the relay control device 10 transmits the power information D1 to the first ECU 21 (step S402 ), and the first ECU 21 executes the stop process (step S403 ).

[0104] By stopping the process, the first ECU 21 changes from the normal state to the sleep state (or the power-off state). When the change is completed, the first ECU 21 stops sending the communication message M1 to the relay control device 10 .

[0105] Based on the power information D1 and the determination result of step S308 , the control unit 12 switches the second relay circuit 32 to the relay off state while maintaining the first relay circuit 31 in the relay on state (switching control: step S404 ). As a result, the power supply to the second ECU 22 is cut off (step S405 ).

[0106] After executing the switching control, the control unit 12 monitors whether the relay control device 10 receives the communication message M1 from the first ECU 21 at intervals within a predetermined time T1 (detection process: step S406 ).

[0107] When the communication message M1 is received within the specified time T1, it means that the first ECU 21 is in a normal state, so it is considered that the stop process (step S403) of the first ECU 21 is in the middle of execution. Therefore, in this case, the control unit 12 maintains the first relay circuit 31 in the relay-on state. That is, when the communication message M1 is received within the specified time T1, the control unit 12 does not output the control signal CS1 for switching from the relay-on state to the relay-off state to the first relay circuit 31.

[0108] After the switching control is executed, if the relay control device 10 does not receive the communication message M1 for more than the specified time T1, it means that the first ECU 21 is in the power off state (or sleep state), so it is considered that the stop process of the first ECU 21 (step S403) is completed. Therefore, in this case, the control unit 12 switches the first relay circuit 31 from the relay on state to the relay off state (step S407). That is, if the communication message M1 is not received for more than the specified time T1, the control unit 12 outputs the control signal CS1 for switching from the relay on state to the relay off state to the first relay circuit 31.

[0109] Through step S407, the power supply to the first ECU 21 is cut off (step S408). Although the power supply to the first ECU 21 is forcibly cut off by the first relay circuit 31, since the stop process has been completed, it is possible to suppress the occurrence of a malfunction in the first ECU 21. Thus, the occurrence of a malfunction can be suppressed, and the first ECU 21 is electrically cut off from the power supply device 60, so that the power consumption in the control system 1 can be suppressed.

[0110] In addition, the relay control device 10 may detect the completion of the stop process in the first ECU 21 by a method other than NM communication. For example, when the stop process is completed, the first ECU 21 may send a completion notification to the relay control device 10 via the communication line 51. In this case, the relay control device 10 switches the first relay circuit 31 from the relay-on state to the relay-off state based on the reception of the completion notification. 2.2 Variations of relay circuits

[0111] Figure 5 1 is a diagram showing a control system 1a according to a modification. In the above-described embodiment, the plurality of relay circuits 30 are provided outside the relay control device 10. In contrast, the relay circuit 30a of this modification is provided inside the relay control device 10a included in the control system 1a.

[0112] Specifically, the plurality of relay circuits 30a are semiconductor relays, and constitute a part of the circuit of the relay control device 10a. The plurality of relay circuits 30a are connected to the microcomputer 11 via the bus B1. The plurality of relay circuits 30a include a first relay circuit 31a connected to the first ECU 21 via the power line 41 and a second relay circuit 32a connected to the second ECU 22 via the power line 42.

[0113] In addition, some of the plurality of relay circuits 30a may be provided inside the relay control device 10a, and other relay circuits 30a may be provided outside the relay control device 10a. That is, in this variation, at least one of the plurality of relay circuits 30a may be provided inside the relay control device 10a.

[0114] By providing the relay circuit 30 a inside the relay control device 10 a , the power line 40 of the control system 1 a can be configured to be shorter, so that the control system 1 a can be made compact and the power loss in the power line 40 can be reduced. 2.3 Switching control via other devices

[0115] Figure 61 is a diagram showing a control system 1b according to a modification. In the control system 1 of the above embodiment, the relay control device 10 is directly connected to the plurality of relay circuits 30 via the power line 40. Furthermore, the control signal CS1 sent from the relay control device 10 is directly input to the plurality of relay circuits 30 without passing through other devices (ECU, etc.).

[0116] In contrast, in the control system 1b according to the modified example, the relay control device 10b is connected to the plurality of relay circuits 30 via the ECU 80 (another device). The control signal CS2 sent from the relay control device 10b is relayed in the ECU 80 and then input to the plurality of relay circuits 30. In addition, the ECU 80 may generate and output a new signal for controlling the plurality of relay circuits 30 based on the control signal CS2.

[0117] The relay control device 10b is, for example, an ECU (power control management ECU) that manages power control in the power supply device 60. The relay control device 10b includes a microcomputer (microcomputer) 11b including a control unit 12b and a storage unit 13b. The microcomputer 11b, the control unit 12b, and the storage unit 13b have the same structures as the microcomputer 11, the control unit 12, and the storage unit 13 in the above-mentioned embodiment. Figure 6 Although not shown in the figure, the relay control device 10b may include a reading unit 14.

[0118] ECU80 is a device other than the relay control device 10b and ECU20 (ECU that controls the power supply by the relay circuit 30), and is an example of "other devices" of the present disclosure. ECU80 may also be a relay device that relays information sent and received between multiple ECU20. Figure 1 The relay control device 10 is in the same position.

[0119] That is, the power line 41 connects the ECU 80 to the first ECU 21 via the first relay circuit 31. The power line 42 connects the ECU 80 to the second ECU 22 via the second relay circuit 32. The power line 43 connects the ECU 80 to the power supply device 60. The communication line 51 connects the ECU 80 to the first ECU 21. The communication line 52 connects the ECU 80 to the second ECU 22.

[0120] In addition, the power line 45 connects the relay control device 10b and the power supply device 60. The communication line 53 connects the relay control device 10b and the power supply control ECU 72. The communication line 55 connects the relay control device 10b and the ECU 80.

[0121] In addition, the relay control device 10 of the above-mentioned embodiment determines the first ECU 21 having the conversion function from among the plurality of ECUs 20 based on the request information D2. In contrast, the first ECU 21 of the present modification sends information indicating that it has the conversion function itself (hereinafter referred to as "function information D3") as the prescribed information. In this case, the first ECU 21 may not send the request information D2 requesting notification of the power supply state to itself.

[0122] Figure 7 : is a flowchart showing a control method according to a modification example. Figure 7 The control performed by the relay control device 10 b in the control shown is realized by the control unit 12 b reading a computer program from the storage unit 13 b (or executing various calculations and processes in accordance with a program written in advance in the control unit 12 b ). Figure 7 The steps shown can also be adjusted in sequence as appropriate. Figure 7 In the control method, Figure 3 The same reference numerals are used for the common steps, and the description thereof will be appropriately omitted.

[0123] First, the vehicle V1 is in the vehicle power off state, and the plurality of relay circuits 30 are all in the relay off state. Therefore, the plurality of ECUs 20 are not supplied with power from the power supply device 60, and all the plurality of ECUs 20 are in the power off state.

[0124] The ECU 80 , the power supply control ECU 72 , and the relay control device 10 b are supplied with electric power from the power supply device 60 via the power lines 43 , 44 , 45 regardless of the power supply state of the vehicle V1 (constant power supply: steps S101 , S102 , S103 ).

[0125] When the power state of the vehicle V1 becomes the IG-on state (step S201 ), the power control ECU 72 transmits power information D1 indicating that the power state of the vehicle V1 is the IG-on state to the relay control device 10 b via the communication line 53 (step S301 ).

[0126] Based on the power supply information D1, the control unit 12b sends a control signal CS2 for switching the plurality of relay circuits 30 from the relay-off state to the relay-on state to the ECU 80 (step S601). Based on the control signal CS2, the ECU 80 switches the plurality of relay circuits 30 from the relay-off state to the relay-on state (step S302). Thus, power is supplied to the first ECU 21 and the second ECU 22 (steps S303 and S304).

[0127] When receiving the power supply, the first ECU 21 performs the startup process (step S305). After that, the first ECU 21 sends the function information D3 to the relay control device 10b in order to notify the relay control device 10b that it has the conversion function (steps S311, S312). Specifically, the function information D3 is sent from the first ECU 21 to the ECU 80 via the communication line 51 (step S311), and then sent from the ECU 80 to the relay control device 10b via the communication line 55 (step S312).

[0128] As described above, the function information D3 is information specifically used to indicate that the first ECU 21 has a conversion function, and may not include information (e.g., request information D2) requesting that other information be sent to the first ECU 21. The function information D3 may also include software version information of the first ECU 21, application information related to applications held by the first ECU 21, or service information related to services provided by the first ECU 21.

[0129] The control unit 12b determines the first ECU 21 from among the plurality of ECUs 20 based on the received function information D3 (determination process: step S602). The function information D3 is information indicating that the ECU 20 of the transmission source has the conversion function (that is, information indicating that it is the first ECU 21), so the control unit 12b can determine the first ECU 21 based on the function information D3. The control unit 12b stores the ECU 20 of the transmission source included in the function information D3 as the first ECU 21 in the storage unit 13.

[0130] After the power state of the vehicle V1 is changed from the IG ON state to the vehicle power OFF state (or the ACC ON state) (step S202 ), the power control ECU 72 transmits power information D1 indicating the current power state to the relay control device 10 b via the communication line 53 (step S401 ).

[0131] Based on the power information D1 and the result of the determination process, the relay control device 10b maintains the first relay circuit 31 in the relay-on state and sends a control signal CS2 for switching the second relay circuit 32 to the relay-off state to the ECU 80 (switching control: step S603). In step S603, the relay control device 10b sends the power information D1 together with the control signal CS2 to the ECU 80.

[0132] Based on the control signal CS2 , the ECU 80 switches the second relay circuit 32 to the relay-off state while maintaining the first relay circuit 31 in the relay-on state (step S404 ). As a result, the power supply to the second ECU 22 is cut off (step S405 ).

[0133] The ECU 80 transmits the power supply information D1 received from the relay control device 10 b to the first ECU 21 (step S409 ). Based on the received power supply information D1 , the first ECU 21 executes the stop process (step S410 ).

[0134] As described above, the relay control device 10b may be connected to the relay circuit 30 via the ECU 80 (other device). Even in such a configuration, the power supply to the first ECU 21 is maintained, so that it is possible to avoid forced cutoff of the power supply during the stop process of the first ECU 21. Thus, the occurrence of a malfunction in the first ECU 21 can be suppressed.

[0135] When the first relay circuit 31 is in the relay-on state, the predetermined information sent by the first ECU 21 to the relay control device 10b may be request information D2 or function information D3. The predetermined information may be information indicating that the first ECU 21 has a conversion function, and its content and form are not particularly limited. 2.4 Variation of the determination process

[0136] The control unit 12 according to the above-described embodiment determines the first ECU 21 from among the plurality of ECUs 20 in the determination process, and then determines the relay circuit 30 corresponding to the first ECU 21 to be the first relay circuit 31 .

[0137] However, the control unit 12 may determine the second ECU 22 (ie, an ECU 20 other than the first ECU 21 ) from among the plurality of ECUs 20 . Alternatively, the control unit 12 may determine the first relay circuit 31 (or the second relay circuit 32 ) directly from among the plurality of relay circuits 30 without going through the ECU 20 . 2.5 Variation of relay disconnection control

[0138] In step S404 of the above embodiment, all second relay circuits 32 are switched to the relay-off state. However, the control unit 12 may switch only predetermined second relay circuits 32 to the relay-off state and maintain the other second relay circuits 32 in the relay-on state.

[0139] For example, when a part of the second ECU 22 (hereinafter referred to as "second ECU 22a") is an accessory driving ECU, it operates in a normal state when the power state of the vehicle V1 is the IG on state or the ACC on state, and becomes the power off state when the vehicle power is off. Therefore, the control unit 12 sets the second relay circuit 32 connected to the second ECU 22a to the relay on state when the IG is on state or the ACC is on state, and sets it to the relay off state when the vehicle power is off.

[0140] Furthermore, when the second ECU 22 other than the second ECU 22a (hereinafter referred to as "the second ECU 22b") is an ignition-driven ECU, it operates in a normal state when the power state of the vehicle V1 is the IG-on state, and becomes the power-off state when the ACC is on or the vehicle power is off. Therefore, the control unit 12 sets the second relay circuit 32 connected to the second ECU 22b to the relay-on state when the IG is on, and to the relay-off state when the ACC is on or the vehicle power is off.

[0141] In this case, for example, in step S202 ( Figure 3 ), when changing from the IG on state to the ACC on state, the control unit 12 in step S404 switches the second relay circuit 32 connected to the second ECU 22b to the relay off state while maintaining the second relay circuit 32 connected to the second ECU 22a in the relay on state. 2.5 Variations of Specified Information

[0142] In the above-mentioned embodiment, the prescribed information (request information D2) is sent from the first ECU 21 to the relay control device 10. However, the relay control device 10 may also store the prescribed information in advance (i.e., before the switching control). For example, information indicating which ECU 20 among the plurality of ECUs 20 is the first ECU 21 may be stored in the storage unit 13 as prescribed information. In this case, the control unit 12 performs the switching control based on the prescribed information read from the storage unit 13. The prescribed information may also be stored in the storage unit 13, for example, by the operator who connects the ECU 20 to the relay control device 10 using an input unit not shown in the figure to teach whether the ECU 20 connected to the relay control device 10 is the first ECU 21. 2.6 Other variations

[0143] The relay control device 10 of the above embodiment determines which relay circuit 30 is switched to the relay-off state in the control unit 12 (step S308: Figure 3 ). However, the relay control device 10 may receive an instruction from another device (for example, another ECU not shown in the figure) and switch the relay circuit 30 to the relay-off state based on the instruction.

[0144] For example, the relay control device 10 transmits the specified information to the other device in step S308. Then, the other device performs the determination process, and transmits the instruction information indicating the relay circuit 30 switched to the relay-off state among the plurality of relay circuits 30 from the other device to the relay control device 10. In step S404, the relay control device 10 switches the second relay circuit 32 to the relay-off state based on the received instruction information. By configuring in this way, the processing load in the relay control device 10 can be reduced. 3. Supplement

[0145] In addition, about the above-mentioned embodiment and various modification examples, at least a part of them can also be arbitrarily combined with each other. In addition, it should be considered that the embodiment and modification examples disclosed this time are illustrative and non-restrictive in all aspects. The scope of the present disclosure is represented by the claims, and it is intended to include all changes within the meaning and scope equivalent to the claims. Description of Reference Numerals

[0146] 1.1a,1b control system

[0147] 10, 10a, 10b relay control device

[0148] 11.11b Microcomputer (microcomputer)

[0149] 12. 12b Control unit

[0150] 13. 13b Storage unit

[0151] 14 Reading unit

[0152] 15 Recording Media

[0153] 20ECU

[0154] 21First ECU

[0155] 22, 22a, 22b Second ECU

[0156] 30, 30a relay circuit

[0157] 31, 31a first relay circuit

[0158] 32, 32a Second relay circuit

[0159] 40 Power Lines

[0160] 41, 42, 43, 44, 45 power lines

[0161] 50 communication lines

[0162] 51, 52, 53, 54, 55 communication lines

[0163] 60 Power supply unit

[0164] 61 Battery

[0165] 62 auxiliary batteries

[0166] 71 Ignition switch

[0167] 72 Power supply control ECU

[0168] 80ECU (other devices)

[0169] V1 Vehicle

[0170] D1 power supply information

[0171] D2 Request Information

[0172] D3 function information

[0173] CS1 control signal

[0174] CS2 control signal

[0175] B1 Bus

[0176] T1 stipulated time

[0177] M1 communication message.

Claims

1. A relay control device, mounted on a vehicle, The relay control device includes a control unit that switches between a relay-on state in which power is supplied to each of a plurality of relay circuits connected to each of a plurality of ECUs and a relay-off state in which power is not supplied to the ECUs. The plurality of ECUs include: The first ECU has a transition function of changing its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; and The second ECU, which does not have the conversion function, The control unit performs the following switching control: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is to be switched from the relay-on state to the relay-off state as the power supply state changes, a second relay circuit connected to the second ECU among the plurality of relay circuits is switched to the relay-off state while maintaining a first relay circuit connected to the first ECU among the plurality of relay circuits in the relay-on state.

2. The relay control device according to claim 1, wherein: When the first relay circuit is in the relay-on state, the first ECU sends predetermined information indicating that the first ECU has the conversion function to the relay control device. The control unit performs the switching control based on the predetermined information.

3. The relay control device according to claim 2, wherein: After the switching control is executed, when the relay control device receives a communication message for detecting communication with the first ECU at intervals within a predetermined time, the control unit maintains the first relay circuit in the relay-on state, After the switching control is executed, if the relay control device does not receive the communication message for a predetermined period of time, the control unit switches the first relay circuit to the relay-off state.

4. The relay control device according to claim 2 or 3, wherein: The prescribed information includes information requesting notification of the power supply state to the first ECU.

5. The relay control device according to claim 2 or 3, wherein: The control unit determines the first ECU from among the plurality of ECUs, or determines the first relay circuit from among the plurality of relay circuits, based on the predetermined information.

6. The relay control device according to claim 2 or 3, wherein: The relay control device is directly connected to a relay circuit provided outside the relay control device among the plurality of relay circuits through a power line or is connected via another device.

7. The relay control device according to claim 2 or 3, wherein: At least one of the plurality of relay circuits is disposed inside the relay control device.

8. A control system comprising: The relay control device according to claim 2 or 3; a plurality of said ECUs including said first ECU; and A plurality of the relay circuits including the first relay circuit.

9. A control method, comprising: controlling a plurality of relay circuits respectively connected to a plurality of ECUs by a relay control device mounted on a vehicle, The plurality of ECUs include: The first ECU has a transition function of changing its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; as well as The second ECU, which does not have the conversion function, The control method comprises: a switching step of switching each of the plurality of relay circuits between a relay-on state in which power is supplied to the ECU and a relay-off state in which power is not supplied to the ECU; The switching step includes the following steps: when the plurality of relay circuits are respectively in the relay-on state, when the second ECU is to be switched from the relay-on state to the relay-off state as the power supply state changes, while maintaining the first relay circuit connected to the first ECU in the plurality of relay circuits in the relay-on state, the second relay circuit connected to the second ECU in the plurality of relay circuits is switched to the relay-off state.

10. A computer program for controlling a plurality of relay circuits respectively connected to a plurality of ECUs by a relay control device mounted on a vehicle, The plurality of ECUs include: The first ECU has a transition function of changing its own operating state between at least two states of a normal state, a sleep state, and a power-off state according to a power state of the vehicle; as well as The second ECU, not including the shift function, The computer program causes the computer to execute: a switching step of switching each of the plurality of relay circuits between a relay-on state in which power is supplied to the ECU and a relay-off state in which power is not supplied to the ECU, The switching step includes the following steps: when the second ECU is to be switched from the relay-on state to the relay-off state as the power supply state changes, while maintaining the first relay circuit connected to the first ECU among the multiple relay circuits in the relay-on state, the second relay circuit connected to the second ECU among the multiple relay circuits is switched to the relay-off state.

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