JP2021059273A - On-vehicle communication system and power source control method - Google Patents

Abstract

To provide an on-vehicle communication system in which dark current can be easily reduced, while avoiding an increase in costs.SOLUTION: An on-vehicle communication system includes: control power supply lines 52 capable of supplying source power from a master device 10 to one or more devices among a plurality of slave devices 20-1 to 20-n; a power supply switching part which is arranged in the master device and switches between on and off of power supply to the control power supply lines; and a master control part which is disposed in the master device, and grasps a situation of the plurality of slave devices according to multiplex communication utilizing a communication line 53, and in which the situation is reflected in control of the power supply switching part. Since source power supply to a slave is stopped, communication IF in the slave and power consumption of a CPU disappear so that dark current is surely reduced. The dark current is reduced individually per priority group by using the plurality of control power supply lines 52.SELECTED DRAWING: Figure 1

Description

The present invention relates to an in-vehicle communication system and a power supply control method, and more particularly to a technique for reducing dark current.

Generally, on a vehicle, an aggregate of electric wires is formed between an in-vehicle battery or alternator (generator), which is the main power source, and various types of electrical components arranged at various locations on the vehicle. They are connected to each other via a certain wire harness. Therefore, the electric power stored in the in-vehicle battery can be supplied to various electrical components as power supply power. Also, even when the vehicle is parked, electrical components such as security devices and audio devices may require power. Therefore, the power of the vehicle-mounted battery flows out even when the vehicle is parked, unless the power supply path of the power supply is cut off by using a relay or the like.

Then, for example, when the electric power stored in the in-vehicle battery is exhausted during parking, the engine cannot be started. In order to prevent such a dead battery, there is a technique for reducing the power consumed as dark current when the engine is stopped on the vehicle.

For example, the power management device of Patent Document 1 shows a technique for detecting the state of a secondary battery even after the engine is stopped and reducing the power consumption of the device itself. Specifically, in the configuration shown in FIG. 1 of Patent Document 1, a dark current monitoring device 11 and a secondary battery state detecting device 13 are provided. Further, the dark current monitoring device 11 and the secondary battery state detection device 13 are connected via a communication line 31 of a LIN (Local Interconnect Network) bus. Further, the dark current monitoring device 11 and the plurality of ECUs (electronic control units) 17, 18 and 19 are connected via a communication line 32 of a CAN (Controller Area Network) bus. The dark current monitoring device 11 has a function of monitoring the dark current flowing through the ECU, the load, and the like while the vehicle is stopped, and limiting or stopping the supply of electric power to the load as needed.

JP-A-2018-170172

However, in the technique of Patent Document 1, since it is necessary to add a dedicated dark current monitoring device 11 to the system in order to monitor the dark current, there is a concern that the cost will increase. Further, although this device can monitor the dark current of the entire system, it cannot individually monitor the dark current generated for each ECU or each load, for example.

Further, in the configuration of FIG. 1 of Patent Document 1, the dark current monitoring device 11 uses a common communication line 32 in order to control the dark currents of the plurality of ECUs 17 to 19. Therefore, in order to control the dark current, it is necessary to keep the communication line 32 in a state where it can be used at all times. However, even in the sleep state where the power consumption is small, each ECU wakes up when communicating using the communication line 32, so that the power consumption in the internal device (bus transceiver, microcomputer, etc.) becomes large and the dark current becomes large. Increases. Furthermore, even if it does not communicate with itself, it temporarily wakes up in response to noise (signals unrelated to itself) generated on the common communication line 32 due to communication with other ECUs, so at that time. The dark current increases.

For example, in the case of shipping a product vehicle for export, the in-vehicle battery remains uncharged for a long period of time, so that even a relatively small dark current may cause the battery to run out. Therefore, in order to prevent the battery from running down, the dark current may be cut off by manually removing the physical fuse of each vehicle in advance at the time of export. Even if this fuse is removed, the vehicle can only run, so it can move by itself during export work. However, in that case, it is necessary to add a special manual process, which complicates the management at the time of export.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an in-vehicle communication system and a power supply control method in which it is easy to reduce a dark current while avoiding an increase in cost.

In order to achieve the above-mentioned object, the in-vehicle communication system and the power supply control method according to the present invention are characterized by the following (1) to (5).
(1) An in-vehicle communication system having a master device and a plurality of slave devices connected under the master device via a common communication line.
One or more control power lines capable of supplying power from the master device to at least one of the plurality of slave devices.
A power supply switching unit that is arranged in the master device and switches the power supply on / off to the control power supply line.
A master control unit that is arranged in the master device and grasps the status of the plurality of slave devices by multiplex communication using the communication line, and reflects the status of the plurality of slave devices in the control of the power supply switching unit. When,
An in-vehicle communication system characterized by being equipped with.

(2) The plurality of slave devices are divided into a plurality of groups according to at least a priority.
There are multiple control power lines,
The plurality of slave devices are connected to the control power supply lines that are independent of each other for each group.
The power supply switching unit individually switches the power supply on / off for each of the plurality of control power lines.
The in-vehicle communication system according to (1) above.

(3) Each of the slave devices measures the dark current flowing through the load connected to itself or its downstream, and measures the dark current.
When the master control unit of the master device detects an abnormality based on the magnitude of the dark current measured by each of the slave devices, the master control unit controls the power supply switching unit to the corresponding control power supply line. Stop power supply,
The in-vehicle communication system according to (1) above.

(4) A power sensor for measuring the storage status of the vehicle-side power supply device capable of supplying power supply to the master device is provided.
The master control unit of the master device reflects the measurement result of the power supply sensor in the control of the power supply switching unit.
The in-vehicle communication system according to any one of (1) to (3) above.

(5) A power supply control method for controlling an in-vehicle communication system having a master device and a plurality of slave devices connected under the master device via a common communication line.
The master device and at least one of the plurality of slave devices are connected via one or more control power lines.
On the master device side, the status of the plurality of slave devices can be grasped by multiplex communication using the communication line.
The on / off of the power supply to the control power supply line is switched according to the situation of the plurality of slave devices grasped by the master device side.
A power control method characterized by that.

According to the in-vehicle communication system having the configuration of (1) above, the master control unit in the master device can control the power supply switching unit according to the situation of the plurality of slave devices. That is, the master device can cut off the power supply power supplied to each slave device via the control power supply line as needed. When the supply of power supply power via the control power supply line is stopped, the dark current consumed by the corresponding slave device becomes zero, and the dark current of the entire vehicle is surely reduced. Further, since the master control unit in the master device can perform multiplex communication with the slave device to which the power supply power is supplied via the control power supply line by using the communication line, necessary information from each slave device. Can be collected. For example, the power supply can be cut off for a slave device having an abnormally large dark current.

According to the in-vehicle communication system having the configuration of (2) above, the master device powers the slave device belonging to the low priority group while maintaining the power supply to the slave device belonging to the high priority group, for example. Only the power supply can be cut off. As a result, the dark current consumed by each slave device in the low priority group becomes zero, so that the dark current consumed by the entire vehicle can be reliably reduced without stopping the function of the high priority group.

According to the in-vehicle communication system having the configuration of (3) above, the master control unit of the master device appropriately controls the on / off of the power supply based on the magnitude of the dark current actually consumed by each slave device. it can. That is, while the actual dark current is small, the power supply can be supplied to the slave device having a low priority to utilize its function, and when the actual dark current becomes large, the power supply is supplied. It can be stopped to reduce dark current.

According to the in-vehicle communication system having the configuration of (4) above, the master device can perform appropriate control according to the actual storage status of the vehicle-side power supply device. For example, when the remaining charge of the vehicle-side power supply device is relatively large, the threshold value indicating the abnormal value of the dark current consumed by each slave device can be increased, and when the remaining charge of the vehicle is relatively small, the threshold value can be decreased. ..

According to the power supply control method having the configuration of (5) above, the master device can cut off the power supply power supplied to each slave device via the control power supply line as needed. When the supply of power supply power via the control power supply line is stopped, the dark current consumed by the corresponding slave device becomes zero, and the dark current of the entire vehicle is surely reduced. In addition, since the master device can perform multiplex communication with the slave device to which power is supplied via the control power supply line using the communication line, it is possible to collect necessary information from each slave device. it can. For example, the power supply can be cut off for a slave device having an abnormally large dark current.

According to the in-vehicle communication system and the power supply control method of the present invention, it becomes easy to reduce the dark current while avoiding the cost increase. That is, there is no need to add a special device for detecting the dark current. Further, by cutting off the power supply power supplied to each slave device via the control power supply line, the dark current consumed by the corresponding slave device can be reliably reduced.

The present invention has been briefly described above. Further, the details of the present invention will be further clarified by reading through the embodiments described below (hereinafter referred to as "embodiments") with reference to the accompanying drawings. ..

FIG. 1 is a block diagram showing a configuration example-1 of an in-vehicle communication system. FIG. 2 is a block diagram showing a configuration example of the master control unit in FIG. FIG. 3 is a block diagram showing a configuration example of the slave control unit in FIG. FIG. 4 is a block diagram showing a configuration example-2 of an in-vehicle communication system. FIG. 5 is a block diagram showing a configuration example of the master control unit in FIG. FIG. 6 is a flowchart showing a main operation in the master control unit. FIG. 7 is a flowchart showing a main operation in the slave control unit.

Specific embodiments of the present invention will be described below with reference to the respective figures.

<Configuration example of in-vehicle communication system>
FIG. 1 shows a configuration example-1 of an in-vehicle communication system that implements the present invention. Further, FIG. 2 and FIG. 3 show configuration examples of the master control unit 10 and one slave control unit 20 included in the in-vehicle communication system 100 of FIG. 1, respectively.

The in-vehicle communication system 100 shown in FIG. 1 is mounted on a vehicle such as a hybrid vehicle, and has a function of supplying the power source power stored in the in-vehicle battery 30 to various loads on the vehicle. The in-vehicle battery 30 is a secondary battery, and for example, a DC power source having a voltage of about 200 [V] can be charged and stored as needed, and supplied to the power supply line 51. In the example shown in FIG. 1, the battery sensor 31 is connected to the vehicle-mounted battery 30 in order to facilitate grasping the storage status of the vehicle-mounted battery 30. The battery sensor 31 can detect the current value and voltage when the in-vehicle battery 30 is charged and discharged. The information detected by the battery sensor 31 is input to the master control unit 10 via the signal line 54. The battery sensor 31 is not an essential component.

In the example shown in FIG. 1, n sets of loads 40-1, 40-2, ..., 40-n on the vehicle are subjected to slave control units 20-1, 20-2, ..., 20-, respectively. It is assumed that n is individually controlled. Therefore, n sets of loads 40 are connected to the output terminals of the slave control units 20-1, 20-2, ..., 20-n via the output lines 55-1, 55-2, ... 55-n, respectively. -1, 40-2, ..., 40-n are connected. Loads on vehicles include electrical components such as various electric motors, various lighting lamps, meter units, various ECUs, audio devices, navigation devices, and security devices.

Each slave control unit 20-1 to 20-n has a voltage regulator (REG) 21, a microprocessor (CPU) 22, a communication interface (IF) 23, and a driver 24, as in the slave control unit 20 shown in FIG. Is built-in.

The driver 24 in the slave control unit 20 includes a semiconductor switching element, and can switch the energization of the load 40 connected to the output line 55 on / off under the control of the microcomputer 22. That is, when the switch in the driver 24 is on, the DC power supply of the control power supply line 52 can be supplied to one end of the load 40 via the output line 55 to drive the load 40. The other end of each load 40-1 to 40-n is connected to the ground 32.

The voltage regulator 21 has a stable DC power supply voltage (for example, +5 [V]) required by electronic devices such as the microcomputer 22 and the communication interface 23 and other circuits based on the DC power supply voltage supplied from the control power supply line 52. ) Can be generated.

The DC power source power generated by the voltage regulator 21 is supplied to the microcomputer 22, the communication interface 23, and the like via the power supply path 26. However, when the power supply power is not supplied to the control power supply line 52, the supply of the power supply power to the microcomputer 22 and the communication interface 23 is also stopped.

The microprocessor 22 operates according to a program built in in advance, and realizes the main control functions required for each slave control unit 20. That is, the microprocessor 22 communicates with the master control unit 10 via the communication interface 23 to send and receive various required information, and the driver responds to an instruction from the master control unit 10. It has a function of controlling the on / off of the 24 and a function of measuring the current consumption (dark current) in the slave control unit 20.

The communication interface 23 is a bus transceiver corresponding to an in-vehicle communication standard such as CAN, and can perform multiplex communication with the master control unit 10 via a communication line 53 to transmit and receive information.

The microprocessor 22 can significantly reduce its own power consumption by shifting from the normal mode to the sleep mode when operation is rarely required. However, even when the microcomputer 22 is in the sleep mode, when some signal appears on the communication line 53, the microcomputer 22 wakes up temporarily due to the output of the communication interface 23 that monitors the signal. Transition to normal mode. Therefore, even in the sleep mode, the microprocessor 22 can monitor whether or not the information addressed to itself appears on the communication line 53.

However, when wake-up, the power consumption of the microcomputer 22 temporarily increases as compared with the sleep mode state. Further, even when a signal not addressed to oneself, that is, noise appears on the communication line 53, the microprocessor 22 wakes up, so that the power consumption temporarily increases. Further, not only the microprocessor 22 but also the communication interface 23 consumes power.

That is, since the communication interface 23 and the microprocessor 22 consume power in order to monitor the presence or absence of communication addressed to oneself using the communication line 53, the slave while the power supply power is supplied to the control power supply line 52. There is a possibility that a relatively large dark current flowing toward the inside of the control unit 20 is constantly generated.

However, in the in-vehicle communication system 100 having the configuration shown in FIG. 1, the power supply to the control power supply line 52 can be stopped as needed by the control of the master control unit 10. When the power supply to the control power supply line 52 is stopped, the dark current consumed by the microcomputer 22 and the communication interface 23 in the slave control unit 20 becomes zero. That is, the dark current of the slave control unit 20 can be reliably reduced by controlling the control power supply line 52.

The in-vehicle communication system 100 shown in FIG. 1 includes a master control unit 10 as a higher-level unit that collectively controls a plurality of slave control units 20-1 to 20-n. Further, as shown in FIG. 1, the master control unit 10 and the plurality of slave control units 20-1 to 20-n are connected to each other via a control power supply line 52 and a communication line 53, respectively.

Therefore, when power is supplied to each of the slave control units 20-1 to 20-n via the control power supply line 52, the master control unit 10 and the plurality of slave control units 20-1 to 20-n It is possible to communicate with each of them by multiplex communication such as CAN via the communication line 53.

As shown in FIG. 2, the master control unit 10 includes a voltage regulator 11, a microcomputer 12, a communication interface 13, and a power switch unit 14. Further, a power supply line 51 and a control power supply line 52 are connected to the power supply input terminal 10a and the power supply output terminal 10b of the master control unit 10, respectively.

The voltage regulator 11 has a stable DC power supply voltage (for example, +5 [V]) required by electronic devices such as the microcomputer 12 and the communication interface 13 and other circuits based on the DC power supply voltage supplied from the power supply line 51. Can be generated. The DC power source power generated by the voltage regulator 11 is supplied to the microcomputer 12, the communication interface 13, and the like via the power supply path 16.

The microprocessor 12 operates according to a program built in in advance, and realizes the main control functions required for the master control unit 10. That is, it communicates with each slave control unit 20 via the communication interface 13 and connects to each slave control unit 20 in response to a function of transmitting and receiving various required information, a predetermined user operation input, and the like. A function of generating commands related to on / off of the load 40, a function of grasping the current consumption (dark current) of each slave control unit 20 to determine the presence or absence of an abnormality, a function of controlling the power switch unit 14, etc. Is provided in the microcomputer 12.

The communication interface 13 is a bus transceiver corresponding to an in-vehicle communication standard such as CAN, and can perform multiplex communication with each slave control unit 20 via a communication line 53 to transmit and receive information.

The power switch unit 14 has a built-in semiconductor switching element capable of switching on / off of energization between the power supply line 51 and the control power supply line 52. The control input terminal of the semiconductor switching element is connected to the output port of the microcomputer 12 via the control line 15.

Therefore, the microcomputer 12 can switch the power switch unit 14 on and off. That is, when the master control unit 10 wants to use each of the subordinate slave control units 20 in a normal state, the microcomputer 12 turns on the power switch unit 14 and controls the DC power supply equivalent to the power supply line 51. Supply to 52. Further, when it is desired to reduce the dark current in the slave control unit 20, the microcomputer 12 in the master control unit 10 turns off the power switch unit 14 to stop the power supply to the control power line 52.

<Modified example of configuration of in-vehicle communication system>
FIG. 4 shows a configuration example-2 of the in-vehicle communication system. Further, FIG. 5 shows the internal configuration of the master control unit 10A in FIG. The in-vehicle communication system 100A shown in FIG. 4 is a modification of the in-vehicle communication system 100 of FIG. 1, and the same components are shown with the same reference numerals.

In the vehicle-mounted communication system 100A of FIG. 4, it is assumed that the slave control units 20-1 to 20-n include a plurality of groups having different priorities. That is, the group of the slave control unit 20-1 and the group of the slave control units 20-2 to 20-n are divided in advance so as to be different.

The master control unit 10A is provided with a plurality of power output terminals 10b-1 and 10b-2 that are independent of each other so that the plurality of groups of the slave control units 20 can be individually controlled. Further, as shown in FIG. 4, one power output terminal 10b-1 of the master control unit 10A is connected to the power input terminal of the slave control unit 20-1 belonging to one group via the control power supply line 52A. ing. The other power output terminal 10b-2 of the master control unit 10A is connected to the power input terminals of the slave control units 20-2 to 20-n belonging to the other group via the control power supply line 52B.

As shown in FIG. 5, a plurality of power switch units 14A and 14B are provided inside the master control unit 10A. The microcomputer 12 in the master control unit 10A can individually control the on / off of the plurality of power switch units 14A and 14B via the control lines 15A and 15B.

When the power switch unit 14A is on, the power switch unit 14A supplies the power supply power of the power supply line 51 to the control power supply line 52A on the downstream side via the power supply output terminal 10b-1. When the power switch unit 14B is on, the power switch unit 14B supplies the power supply power of the power supply line 51 to the control power supply line 52B on the downstream side via the power supply output terminal 10b-2. When the power switch unit 14A is turned off, the power supply to the control power supply line 52A is stopped, and when the power switch unit 14B is turned off, the power supply to the control power supply line 52B is stopped.

Therefore, the microcomputer 12 in the master control unit 10A can individually control the on / off of the power supply power supply for each group of the slave control units 20 by individually controlling the on / off of the plurality of power switch units 14A and 14B.

For example, when the priority of the load 40-1 is higher than that of the other loads 40-2 to 40-n, only the power supply to the control power supply line 52B is stopped, so that the slave control unit 20-2 The master control unit 10A can control only the slave control unit 20-1 to maintain the operating state by switching all ~ 20-n to non-operation to reduce the dark current.

On the contrary, when the priority of the load 40-1 is lower than that of the other loads 40-2 to 40-n, the power supply is stopped only by the slave control unit 20-1 having a large dark current in the control power line 52A. The dark current can be reduced, and the master control unit 10A can control the other slave control units 20-2 to 20-n so as to maintain the operating state.

<Operation of master control unit>
FIG. 6 shows the main operations of the master control units 10 and 10A described above. That is, the microcomputer 12 in the master control unit 10 executes the process shown in FIG. The microprocessor 12 starts the operation from step S11 when the power supply is started or when a predetermined reset signal is applied. The operation of the master control unit 10 shown in FIG. 6 will be described below.

The master control unit 10 first executes initialization in S11. As a result of this initialization, power supply to the control power supply lines 52 shown in FIG. 1 and the control power supply lines 52A and 52B shown in FIG. 4 is started. Therefore, each of the slave control units 20-1 to 20-n under the master control unit 10 is put into operation. In addition, it is initialized to a state in which multiplex communication using the communication line 53 is possible.

The master control unit 10 performs normal load control in S12. For example, by monitoring an input port (not shown), a user's switch operation or the like is detected, and the load 40 is driven toward the slave control unit 20 to which the corresponding load 40 is connected according to the result. The command is transmitted by multiplex communication using the communication line 53.

The master control unit 10 periodically executes a process for grasping the charge state of the vehicle-mounted battery 30 in S13. That is, measurement information such as the charge / discharge current value of the in-vehicle battery 30 detected by the battery sensor 31 is acquired, and the microcomputer performs a predetermined calculation process to grasp the latest stored amount.

The master control unit 10 reflects the change in the amount of electricity stored in the vehicle-mounted battery 30 detected in S13 in the dark current threshold value in S14. For example, when the amount of electricity stored in the in-vehicle battery 30 is low, the margin until the battery runs out is small, so the dark current threshold value is updated to a relatively small value. When the amount of electricity stored in the in-vehicle battery 30 is sufficiently large, there is a large margin until the battery runs out, so the dark current threshold value is updated to a relatively large value. When the battery sensor 31 is not provided, the master control unit 10 omits S13 and S14.

The master control unit 10 acquires information on each detected dark current measurement value from each of the slave control units 20-1 to 20-n in S15 by multiplex communication using the communication line 53.

The master control unit 10 calculates the total dark current ix in S16 for each group of the slave control units 20. For example, the total dark current ix of the group to which the slave control units 20-2 to 20-n belong in the in-vehicle communication system 100A of FIG. 4 is the dark current measurement acquired from each of the slave control units 20-2 to 20-n in S15. Calculated as the sum of the values. Further, in the case of the group division shown in FIG. 4, the total dark current ix of the group of the slave control unit 20-1 is the same as the dark current measurement value acquired from the slave control unit 20-1 in S15.

The master control unit 10 compares the total dark current ix calculated in S16 with the dark current threshold value for each group of the slave control units 20 (S17). Then, when the condition of "ix> is" is satisfied, that is, when the dark current detected for each slave group is abnormally large, the next S18 is executed.

The master control unit 10 cuts off the power supply to the slave control unit 20 corresponding to the group in S18 for the group satisfying the condition of “ix> is”. That is, the microprocessor 12 turns off the power switch units 14, 14A, or 14B to stop the power supply to the control power lines 52, 52A, or 52B. As a result, the dark current consumed by the slave control unit 20 of the corresponding group becomes zero.

<Operation of slave control unit>
FIG. 7 shows the main operations of the slave control unit 20. That is, the microcomputer 22 in each slave control unit 20-1 to 20-n executes the process of each step shown in FIG. 7.

When the power supply to the microcomputer 22 is started from the output of the voltage regulator 21 via the power supply path 26, the microcomputer 22 starts the process from step S21 of FIG. After that, the microprocessor 22 and the communication interface 23 consume power while the power supply from the control power supply line 52 continues.

Of course, the power consumption in the slave control unit 20 can be suppressed by shifting the microcomputer 22 to the sleep mode as needed, but even in the sleep mode, if a signal or noise appears on the communication line 53, it will be reduced. Due to the need for monitoring, the microcomputer 22 and the communication interface 23 automatically wake up to increase power consumption.

The microprocessor 22 performs a predetermined initialization in step S21. By this initialization, the output of the driver 24 is turned off, and the microcomputer 22 and the communication interface 23 are in a state where multiplex communication using the communication line 53 is possible.

The microprocessor 22 periodically executes the measurement of the dark current in the slave control unit 20 in S22.
The microprocessor 22 periodically executes bidirectional information transmission with the master control unit 10 by multiplex communication using the communication line 53 in S23.
The microcomputer 22 controls the drive of the load 40 connected to the output of the driver 24 in S24 according to an instruction such as a command received from the master control unit 10 in S23.

As described above, in the in-vehicle communication system 100 according to the embodiment of the present invention, the power supply supplied to the control power supply line 52 by the master control unit 10 without adding a special device for monitoring the dark current. By shutting off the power, the dark current consumed by each slave control unit 20-1 to 20-n can be reliably reduced. Therefore, it is possible to suppress an increase in device cost.

Moreover, since it is not necessary to use the communication line 53 when reducing the dark current, the power consumption caused by the wake-up of the microcomputer 22 and the communication interface 23 in the slave control unit 20 is eliminated, and the dark current is surely reduced. it can. Therefore, even in a situation where the battery is not charged for a long period of time, for example, when the vehicle is shipped and exported, the battery runs out without manually removing the special fuse. Can be prevented.

Further, in the state before the dark current is reduced, since multiplex communication using the communication line 53 is possible, various types can be performed between the master control unit 10 and each slave control unit 20 without increasing the number of wires in the wire harness. Information can be transmitted and fine control can be realized.

Further, when the plurality of control power lines 52A and 52B are individually controlled for each group as in the in-vehicle communication system 100A shown in FIG. 4, the load 40 having a high priority is maintained in a usable state. Until then, only the dark current consumed by each slave control unit 20 of the low priority group can be effectively reduced.

Regarding the dark current threshold value for detecting the abnormality of the dark current, for example, an independent value may be individually assigned to each group according to the priority. Further, the total number of groups, the number of slave control units 20 assigned to each group, and the like can be changed as needed.

Here, the features of the in-vehicle communication system and the power supply control method according to the above-described embodiment of the present invention are briefly summarized and listed below in [1] to [5], respectively.
[1] A master device (master control unit 10) and a plurality of slave devices (slave control units 20-1 to 20-n) connected under the master device via a common communication line (53). In-vehicle communication system (100, 100A) having
One or more control power supply lines (control power supply lines 52, 52A, 52B) capable of supplying power from the master device to at least one of the plurality of slave devices.
A power supply switching unit (power switch unit 14) that is arranged in the master device and switches the power supply on / off to the control power line.
A master control unit that is arranged in the master device, grasps the status of the plurality of slave devices by multiplex communication using the communication line, and reflects the status of the plurality of slave devices in the control of the power supply switching unit. (Microcomputer 12, S11 to S18) and
An in-vehicle communication system characterized by being equipped with.

[2] The plurality of slave devices are divided into a plurality of groups according to at least a priority (see FIG. 4).
There are multiple control power lines,
The plurality of slave devices are connected to the control power supply lines (control power supply lines 52A, 52B) that are independent of each other for each group.
The power supply switching unit (power switch unit 14A, 14B) individually switches the power supply on / off for each of the plurality of control power lines (S18).
The in-vehicle communication system according to the above [1].

[3] Each of the slave devices measures the dark current flowing through the load connected to itself or its downstream (S22).
When the master control unit of the master device detects an abnormality based on the magnitude of the dark current measured by each of the slave devices, the master control unit controls the power supply switching unit to the corresponding control power supply line. Stop the power supply (S15 to S18),
The in-vehicle communication system according to the above [1].

[4] A power sensor (battery sensor 31) for measuring the storage status of the vehicle-side power supply device capable of supplying power supply power to the master device is provided.
The master control unit of the master device reflects the measurement result of the power supply sensor in the control of the power supply switching unit (S13, S14).
The in-vehicle communication system according to any one of the above [1] to [3].

[5] A master device (master control unit 10) and a plurality of slave devices (slave control units 20-1 to 20-n) connected under the master device via a common communication line (53). It is a power supply control method for controlling an in-vehicle communication system (100) having the above.
The master device and at least one of the plurality of slave devices are connected via one or more control power supply lines (control power supply lines 52, 52A, 52B).
On the master device side, the status of the plurality of slave devices can be grasped by multiplex communication using the communication line (S15).
The on / off of the power supply to the control power supply line is switched according to the situation of the plurality of slave devices grasped by the master device side (S16 to S18).
A power control method characterized by that.

10,10A Master control unit 10a Power supply input terminal 10b Power supply output terminal 11,21 Voltage regulator 12,22 Microcomputer 13,23 Communication interface 14 Power supply switch unit 15 Control line 16,26 Power supply path 20 Slave control unit 24 Driver 30 In-vehicle Battery 31 Battery sensor 32 Earth 40 Load 51 Power supply line 52, 52A, 52B Control power supply line 53 Communication line 54 Signal line 55 Output line 100, 100A In-vehicle communication system ix Dark current total with dark current threshold

Claims (5)

An in-vehicle communication system having a master device and a plurality of slave devices connected under the master device via a common communication line.
One or more control power lines capable of supplying power from the master device to at least one of the plurality of slave devices.
A power supply switching unit that is arranged in the master device and switches the power supply on / off to the control power supply line.
A master control unit that is arranged in the master device and grasps the status of the plurality of slave devices by multiplex communication using the communication line, and reflects the status of the plurality of slave devices in the control of the power supply switching unit. When,
An in-vehicle communication system characterized by being equipped with. The plurality of slave devices are divided into a plurality of groups according to at least a priority.
There are multiple control power lines,
The plurality of slave devices are connected to the control power supply lines that are independent of each other for each group.
The power supply switching unit individually switches the power supply on / off for each of the plurality of control power lines.
The in-vehicle communication system according to claim 1. Each of the slave devices measures the dark current flowing through itself or a load connected downstream thereof.
When the master control unit of the master device detects an abnormality based on the magnitude of the dark current measured by each of the slave devices, the master control unit controls the power supply switching unit to the corresponding control power supply line. Stop power supply,
The in-vehicle communication system according to claim 1. A power sensor for measuring the storage status of the vehicle-side power supply device capable of supplying power supply power to the master device is provided.
The master control unit of the master device reflects the measurement result of the power supply sensor in the control of the power supply switching unit.
The in-vehicle communication system according to any one of claims 1 to 3, wherein the in-vehicle communication system is characterized by the above. A power supply control method for controlling an in-vehicle communication system having a master device and a plurality of slave devices connected under the master device via a common communication line.
The master device and at least one of the plurality of slave devices are connected via one or more control power lines.
On the master device side, the status of the plurality of slave devices can be grasped by multiplex communication using the communication line.
The on / off of the power supply to the control power supply line is switched according to the situation of the plurality of slave devices grasped by the master device side.
A power control method characterized by that.

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