Vehicle control unit

Abstract

Vehicle control apparatus, which features: a first characteristic device (5) configured to provide a first characteristic function, a second characteristic device (6) configured to provide a second characteristic function, a control device (2, 32) configured to output a control signal to each of the devices, first characteristic device and second characteristic device, via a signal line, and a supply voltage control device (22, 33, 42, 51) which is provided between the control device and the second characteristic device, where: a minimum operating voltage of the first characteristic device is set to be lower than a minimum operating voltage of the second characteristic device, the supply voltage control device is configured to prevent a situation in which a supply voltage of a device power supplied to the second characteristic device becomes less than an input voltage of the signal line of the control signal transmitted from the control device to the second characteristic device. the first characteristic device includes a safety and security device configured to provide, as the function of the first characteristic, a safety and security function necessary to provide safety and security rather than mere amenity and comfort, and The second characteristic device includes a multimedia device configured to provide a multimedia function as the function of the second characteristic, which is not required to provide as much safety and security as the safety and security function.

Description

Cross-reference to a related registration

[0001] This application is based on the Japanese patent application JP 2018 - 242744 A, which was filed on December 26, 2018, and whose contents are hereby incorporated by reference. Technical field

[0002] The present disclosure relates to a vehicle control apparatus. background

[0003] For example, a vehicle, such as an automobile, is equipped with a vehicle control unit that integrally controls a variety of functions with different characteristics. Such a vehicle control unit may have a configuration that includes (i) a first characteristic device providing the function of a first characteristic, (ii) a second characteristic device providing the function of a second characteristic, and (iii) a microcomputer that controls the function of the first characteristic and the function of the second characteristic. Furthermore, in such a configuration, the function of the first characteristic may be one that requires a low-voltage operational guarantee, and the function of the second characteristic may be one that does not require a low-voltage operational guarantee.In such a case, the microcomputer and the first characteristic device can be operated with a first power supply that ensures operation at low voltage, whereas the second characteristic device can be operated with a second power supply that does not ensure operation at low voltage. The first characteristic device can be a safety device that provides a safety function requiring safety rather than convenience. The second characteristic device can be a multimedia device that provides a multimedia function requiring less safety than a safety device.

[0004] A starter activation for starting the vehicle's engine or internal combustion engine requires a high electrical power output, which involves a brief interruption that temporarily reduces the power voltage supplied from the outside to the vehicle's control unit. The configuration described above, in which the microcomputer controls a variety of functions with varying power limitations, must ensure that some functions continue to operate even during this brief interruption. For example, consider a case where the power voltage drops from 10 V or higher to 4 V. In such a case, at 10 V or higher, both the safety and security functions and the multimedia functions operate normally, whereas at 4 V, the multimedia functions must be stopped, while the safety and security functions must continue to operate.

[0005] The procedure for stopping the multimedia function can be executed by the microcomputer, which stops the output of the control signal to the multimedia device when it detects a drop in the power voltage supplied from the external source. Correspondingly, the device power supply to the multimedia device is stopped due to the drop in power voltage. In this case, it is assumed that the device power supply to the multimedia device stops before the input of the control signal from the microcomputer is stopped. According to this assumption, the voltage continues to be applied to the signal line as if the device power supply were not being delivered. Consequently, the device power supply voltage may be lower than the input voltage of the signal line, and there is a risk of device damage.

[0006] As a countermeasure for such a situation, it is conceivable to use software control. For example, JP 2014-197370 A discloses the configuration for using software control when an abnormality occurs.

[0007] From WO 2018 / 135869 A1, a driver assistance system for a collision avoidance control is known, in which the voltage logic and memory logic of a camera system are described.

[0008] From US patent 2019 / 0143968 A1, a driver assistance system for collision avoidance control is known, wherein sensors detect a lane and an external vehicle and thereby control steering, braking or acceleration of the own vehicle. Summary of the invention

[0009] As a countermeasure against device damage when the power voltage drops, a configuration is conceivable in which the microcomputer detects the drop in power voltage and stops the output of the control signal to the multimedia device, as described above. However, in this configuration, even if the interrupt processing is performed in the microcomputer, the control signal may be output immediately after the decrease in power voltage is detected due to processing that was performed earlier. In this case, it becomes difficult to stop the input of the control signal from the microcomputer before the device power supply is stopped, and thus it becomes difficult to prevent device damage.

[0010] It is an objective of the present disclosure to appropriately prevent device damage when the externally supplied power voltage drops. This objective is achieved by the independent claims. Advantageous embodiments are disclosed in the dependent claims.

[0011] According to an example in the present disclosure, a vehicle control apparatus is provided to include a first characteristic device, a second characteristic device, a control device, and a supply voltage control device. The first characteristic device is configured to provide a function of a first characteristic. The second characteristic device is configured to provide a function of a second characteristic. The control device is configured to output a control signal to each of the characteristic devices, first characteristic device and second characteristic device, via a signal line. The supply voltage control device is provided between the control device and the second characteristic device.This specifies a minimum operating voltage for the first characteristic device, which must be lower than the minimum operating voltage of the second characteristic device. The supply voltage control device is configured to prevent a situation where the supply voltage of a device power supplied to the second characteristic device becomes lower than the input voltage of the control signal line transmitted from the control device to the second characteristic device.

[0012] A supply voltage control device is provided between the control device and the second characteristic device. When the power voltage supplied from the outside drops, the supply voltage control device prevents a situation where the supply voltage to the second characteristic device becomes lower than the input voltage of the control signal line transmitted from the control device to the second characteristic device. Consequently, device damage is effectively prevented when the power voltage supplied from the outside decreases. Brief description of the drawings

[0013] The above and other functions, features, and advantages of the present disclosure will become even clearer from the following detailed description, which is made with reference to the accompanying drawings. In the drawings: is Fig. 1 a functional block diagram showing a vehicle control apparatus and a peripheral configuration according to a first embodiment, is Fig. 2 a diagram showing a transition of the power voltage and a transition of the function stop, is Fig. 3 a functional block diagram showing a main part, is Fig. 4 a timing diagram (No. 1), is Fig. 5 a timing diagram (No. 2), is Fig. 6 a functional block diagram showing a configuration of a comparison example, is Fig. 7 a functional block diagram showing a main part according to a second embodiment, is Fig. 8 a functional block diagram showing a main part according to a third embodiment, and is Fig. 9 a functional block diagram showing a main part according to a fourth embodiment. Embodiment for carrying out the invention (First embodiment)

[0014] A first embodiment is described below with reference to FIGS. 1 to 6. A vehicle control unit is used in a vehicle cockpit system. The cockpit system aggregates (i) information about safety and security functions, such as display information, and (ii) information about multimedia functions, such as map and audio information, in a vehicle control unit. The cockpit system prioritizes the different pieces of information to display them quickly and promptly, preventing the driver from overlooking important information. Because the cockpit system has a configuration in which the vehicle control unit manages the input and output information together, the input source and output destination of different pieces of information can be freely changed.The input information includes, for example, vehicle information such as vehicle speed and fuel consumption, digital TV picture information, smartphone cooperation or pairing information linked to a smartphone, and the like. The output information includes (i) screen images displayed on the display element MID screen or display element center screen located in the center of the display element, and the central display screen installed in the center of the vehicle's dashboard, and (ii) the sounds corresponding to the screen images.

[0015] As it is in Fig. As can be seen in Figure 1, the vehicle control apparatus 1 includes (i) a main microcomputer 2 (hereinafter referred to as a control device 2), (ii) a sub-microcomputer 3, (iii) a voltage detector circuit 4, (iv) a safety and security device 5 (i.e. a first characteristic device) and (iv) or (v) a multimedia device 6 (i.e. a second characteristic device).

[0016] In vehicles, for example, safety and security devices, such as display elements, have statutory operating standards or user standards. The safety and security function is designed to require low-voltage operational reliability, so that it can operate even if the power voltage supplied by the vehicle battery drops. In contrast, in vehicles, for example, multimedia devices, such as an audio system, do not have such strict statutory operating standards as display elements. The multimedia function is designed so that it does not require low-voltage operational reliability. In accordance with these circumstances, the vehicle control apparatus 1 (i) includes a functional block (functional block, which is represented by the dashed line A in Fig. (1) which is operated by a safety and security power supply which is a safety and security power supply and requires low-voltage operation, and (ii) a functional block (functional block which is indicated by the dashed line B in Fig. 1), which is powered by a multimedia power supply that is designed for multimedia use and does not require low-voltage operation. The main microcomputer 2, the sub-microcomputer 3, the voltage detector circuit 4, and the safety and security device 5 operate at the power voltage supplied by the safety and security power supply. The multimedia device 6 also operates at the power voltage supplied by the multimedia power supply. This means that the minimum operating voltage of the safety and security device 5 is set lower than the minimum operating voltage of the multimedia device 6.

[0017] The main microcomputer 2 contains a safety function control unit 7 and a multimedia function control unit 8. The safety function control unit 7 outputs a control signal to the safety device 5 to control its operation. The multimedia function control unit 8 outputs a control signal to the multimedia device 6 to control its operation.

[0018] The safety and security device 5 includes, for example, a CAN communication device (Controller Area Network, control unit network) (CAN, registered trademark) 9 and a display element information presentation device 10. The CAN communication device operates based on a control signal supplied by the safety and security function control unit 7 and transmits and receives vehicle information to and from the CAN 14. The display element information presentation device 10 operates based on a control signal supplied by the safety and security function control unit 7, outputs a video signal to the display element center screen 15, and displays a video of the display element information on the display element center screen 15.The safety and security device 5 can be a device that provides functions apart from the communication device 9 and the display element information display device 10.

[0019] The multimedia device 6 includes, for example, a digital television 11, a map information display device 12, and an external cooperation device 13. The digital television 11 operates based on the control signal supplied by the multimedia function control device 8, outputs the video signal to the central display screen 16, and displays the video from the digital television 11 on the central display screen 16. The map information display device 12 operates based on the control signal supplied by the multimedia function control device 8, outputs the video signal to the central display screen 16, and displays the map information video on the central display screen 16.The external cooperation device 13 operates based on the control signal supplied by the multimedia function control device 8 and communicates data linked to an external device, such as a smartphone, with the data communication unit 17. The multimedia device 6 can be a device that provides functions in addition to the digital television 11, the map information display device 12, and the external cooperation device 13.

[0020] As explained above under "Background," a high electrical power is required during a start activation to start the vehicle's engine or internal combustion engine, resulting in a brief interruption during which the power voltage supplied from the outside to the vehicle control unit 1 temporarily drops. In the configuration described above, this occurs when... Fig. As shown in Figure 2, for example, in a state where both the safety and security functions and the multimedia function operate normally at 10 V or higher (e.g., 12 V), if the power voltage drops from 10 V or higher to 4 V, the multimedia function will stop, but the safety and security function must continue. In this case, if the multimedia device 6 stops powering the device before the input of the control signal from the main microcomputer 2 stops, the voltage will be applied to the signal line in a state where the device is not supplying power. As a result, the device power supply voltage may be lower than the signal line input voltage, and there is a risk of device damage.

[0021] In accordance with these circumstances, in order to avoid a situation in which the input voltage of the signal line exceeds the supply voltage of the device power, the configuration described in the present embodiment is Fig. 3 can be seen, used between the main microcomputer 2 and the multimedia device 6. In Fig. 3 the map information display device 12 is described as the multimedia device 6, however the same applies to the digital television 11.

[0022] In the hazard and safety power functional block, voltage generation circuit 18 generates a power voltage of 3.3 V from the main voltage supplied by the vehicle battery via voltage detector circuit 4 and supplies this 3.3 V power voltage to the main microcomputer 2, the sub-microcomputer 3, and the buffer circuit 23, which will be described later. In the multimedia power functional block, voltage generation circuit 19 generates a power voltage of 7.0 V from the sub-voltage supplied by the vehicle battery via voltage detector circuit 4 and supplies this 7.0 V power voltage to voltage generation circuits 20 and 21.Voltage generating circuit 20 generates a power voltage of 3.3 V from the power voltage of 7.0 V supplied by voltage generating circuit 19 and supplies the generated power voltage of 3.3 V to the map information display device 12. Voltage generating circuit 21 generates a power voltage of 8.0 V from the power voltage of 7.0 V supplied by voltage generating circuit 19 and provides the generated power voltage of 8.0 V to the corresponding device (not shown).

[0023] A supply voltage control device circuit 22 (which may also be referred to as a supply voltage control device) is provided as hardware between the main microcomputer 2 and the map information display device 12. Specifically, the supply voltage control device circuit 22 includes (i) a buffer circuit 23, which is provided between the main microcomputer 2 and the map information display device 12, and (ii) a pull-up resistor 26, which energizes, or connects to a higher voltage potential, the signal line 25 on the output side of the buffer circuit 23 to the voltage generation circuit 20. The signal line 24 on the input side of the buffer circuit 23 is connected to the main microcomputer 2. The signal line 25 on the output side of the buffer circuit 23 is connected to the map information display device 12.The buffer circuit 23 contains a buffer IC (integrated circuit) 27 and an NPN-type transistor (negative-positive-negative) 28. The output terminal of the buffer IC 27 is connected to the base terminal of the transistor 28. The collector terminal of the transistor 28 is connected to the card information display device 12 and the pull-up resistor 26 via the signal line 25 on the output side. The emitter terminal of the transistor 28 is grounded. This means that the buffer circuit 23 electrically isolates the hazard and safety performance functional block and the multimedia performance functional block via the transistor 28.

[0024] Next, an operation of the configuration described above will be performed with reference to Fig. 4 and Fig. 5 described. First, assume a state in which a power voltage of 10 V or higher is normally supplied to the vehicle control unit 1 and both the safety and security functional block and the multimedia functional block are operating normally. In such a state, the supply voltage of the device power in the map information display device 12 fulfills the condition of being equal to or higher than the input voltage of the signal line.

[0025] When the voltage detector circuit 4 detects that the power voltage supplied from the outside to the vehicle control device 1 has dropped from 10 V to 4 V, the voltage detector circuit 4 notifies the sub-microcomputer 3 of the voltage drop detection. Upon receiving this notification, the sub-microcomputer 3 sends a power supply stop command to the voltage generation circuit 19. When the voltage detector circuit 4 sends this power supply stop command, the voltage generation circuit 19 stops supplying the power voltage from 7.0 V. This means that the voltage supplied by the voltage generation circuit 19 is unstable, the voltage supplied by the voltage generation circuit 20 is also unstable, and the device power supply voltage is also unstable.As a result, the map information display device 12 changes its state from the normal operating state to the unstable state (t1 in . Fig. 4 and t11 in Fig. 5).

[0026] In this state, the multimedia power functional block ceases operation, while the safety and security functional block continues operation. Therefore, a power voltage of 3.3 V is applied to signal line 24 on the input side of the buffer circuit 23. Conversely, when the multimedia power functional block ceases operation, the power voltage applied by the pull-up resistor 26, or connected to a higher voltage potential, drops accordingly. Consequently, the 3.3 V power voltage is not applied to signal line 25 on the output side of the buffer circuit 23. As a result, in the map information display device 12, the device power supply voltage continues to meet the condition of being equal to or higher than the input voltage of the signal line.

[0027] Afterwards, the output voltage of the control signal from the main microcomputer 2 is temporarily switched off in order to restart the map information display device 12 in its unstable state. In this case, the time during which the output voltage of the control signal from the main microcomputer 2 is switched off does not depend on the time it takes for the power voltage supplied from the outside to the vehicle control unit 1 to be restored.

[0028] Fig. Figure 4 is used to describe a case in which the output voltage of the control signal from the main microcomputer 2 is temporarily switched off before the power voltage supplied from the outside to the vehicle control unit 1 returns from 4 V to 10 V or more. If the output voltage of the control signal from the main microcomputer 2 is switched off once before the power voltage is restored from 4 V to 10 V or more, the map information display device 12 switches from an unstable state to a stopped state (t2 in Fig. 4) When the voltage detector circuit 4 detects that the power voltage supplied from the outside to the vehicle control device 1 has been restored from 4 V to 10 V or more, the voltage detector circuit 4 notifies the sub-microcomputer 3 of the voltage restoration detection. When the voltage restoration detection is reported by the voltage detector circuit 4, the sub-microcomputer 3 notifies the voltage generation circuit 19 of the power supply start command. When the voltage detector circuit 4 sends the power supply start command, the voltage generation circuit 19 starts supplying the power voltage at 7.0 V. That is, the voltage supplied by the voltage generation circuit 19 is 7.0 V, the voltage supplied by the voltage generation circuit 20 is 3.3 V, and the device power supply voltage is 3.3 V (t3 in Fig. 4) Then, when the output voltage of the control signal from the main microcomputer 2 is switched on, the input voltage of the signal line is restored and the map information display device 12 is restored from the stopped state to the normal operating state (t4 in Fig. 4).

[0029] On the other hand Fig. Figure 5 is used to describe a case in which the output voltage of the control signal from the main microcomputer 2 is temporarily switched off after the power voltage supplied from the outside to the vehicle control unit 1 is restored from 4 V to 10 V. When the voltage detector circuit 4 detects that the power voltage supplied from the outside to the vehicle control unit 1 has been restored from 4 V to 10 V or more, the voltage detector circuit 4 notifies the sub-microcomputer 3 of the voltage restoration detection. When the voltage restoration detection is reported by the voltage detector circuit 4, the sub-microcomputer 3 notifies the voltage generation circuit 19 of a power supply start command.When the voltage detector circuit 4 sends the power supply start command, the voltage generation circuit 19 starts supplying the power voltage of 7.0 V. That is, the voltage supplied by the voltage generation circuit 19 is 7.0 V, the voltage supplied by the voltage generation circuit 20 is 3.3 V, and the device power supply voltage is 3.3 V (t12 in . Fig. 5) As soon as the output voltage of the control signal from the main microcomputer 2 is switched off, the input voltage of the signal line drops and the map information display device 12 switches from an unstable state to a stopped state (t13 in Fig. 5) Then, when the output voltage of the control signal from the main microcomputer 2 is switched on, the input voltage of the signal line is restored and the map information display device 12 is restored from the stopped state to the normal operating state (t14 in Fig. 5).

[0030] According to the configuration that is in Fig. As shown in Figure 6, where the supply voltage control circuit 22 is not provided, consider a case where the power voltage supplied from the outside to the vehicle control unit 1 drops from 10 V or more to 4 V. In such a case, the supply of power to the map information display device 12 is stopped before the input of the control signal from the main microcomputer 2 is stopped. As a result, the supply voltage to the device power may be lower than the input voltage of the signal line, and there is a risk that the device may be damaged. On the other hand, in the present embodiment, the supply voltage control circuit 22 is provided to prevent a situation in which the supply of power to the device is stopped before the input of the control signal from the main microcomputer 2 is stopped.Preventing the occurrence of the above situation can prevent the occurrence of a situation where the supply voltage of the device power becomes lower than the input voltage of the signal line.

[0031] The first embodiment enables the following. A drop in the power supply from the outside causes a situation where the supply voltage to the multimedia device 6 becomes lower than the voltage of the control signal line 24 transmitted from the main microcomputer 2 to the multimedia device 6. In the first embodiment, the vehicle control apparatus 1 is equipped with a supply voltage control circuit 22 located between the main microcomputer 2 and the multimedia device 6. Providing such a supply voltage control circuit 22 prevents the occurrence of the above situation. Consequently, software control is not used as a countermeasure against device failure; instead, hardware (i.e., a circuit) is added.This prevents device destruction from occurring when the power voltage supplied from the outside drops.

[0032] Furthermore, the supply voltage control device circuit 22 includes the buffer circuit 23 and the pull-up resistor 26. This can be implemented by a simple circuit using the buffer circuit 23 and the pull-up resistor 26. (Second embodiment)

[0033] A second embodiment is described with reference to Fig. 7. In the following, the description of the same parts as in the first embodiment is omitted, and only the different parts are described. The second embodiment is a configuration in which the buffer circuit 23, described in the first embodiment, is contained or integrated into the main microcomputer.

[0034] As it is in Fig. As shown in Figure 7, the main microcomputer 32 in the vehicle control apparatus 31 contains part of the supply voltage control device circuit 33 (supply voltage control device). Unlike the microcomputer 2 described in the first embodiment, the main microcomputer 32 contains a safety and security function control device 7, a multimedia function control device 8, and a buffer circuit 34. The buffer circuit 34 contains the buffer IC 27 and the transistor 28, as described in the first embodiment, and has the same function as the buffer circuit 23 described in the first embodiment.

[0035] According to the second embodiment, even in a configuration where the buffer circuit 23 is contained or integrated into the main microcomputer 32, the same effects as those described above in the first embodiment can be obtained. Furthermore, since the buffer circuit 34 is contained or integrated into the main microcomputer 32, the number of parts and the board or vehicle-side space can be reduced, and the device can be significantly miniaturized. (Third embodiment)

[0036] A third embodiment is described with reference to Fig. 8. In the following, the description of the same parts as in the first embodiment is omitted, and only the different parts are described. The third embodiment has a configuration in which a level shifter circuit is used instead of the buffer circuit 23 and the pull-up resistor 26 described in the first embodiment.

[0037] As it is in Fig. As shown in Figure 8, a level shifter circuit 43 is provided in the vehicle control apparatus 41 as a supply voltage control device circuit 42 between the main microcomputer 2 and the multimedia function 6. The level shifter circuit 43 converts the output voltage supplied to the signal line 25 from 3.3 V to 0 V when the voltage supplied by the voltage generation circuit 19 becomes unstable and the voltage supplied by the voltage generation circuit 20 becomes unstable. By providing the level shifter circuit 43, it is possible to avoid a situation in which the supply of device power is stopped before the input of the control signal from the main microcomputer 2 is stopped.

[0038] According to the third embodiment, even in a configuration in which the level converter circuit or level transformer circuit 43 is provided as the supply voltage control device circuit 42, the same effects as those in the first embodiment described above can be obtained. (Fourth embodiment)

[0039] A fourth embodiment is described with reference to Fig. 9. In the following, the description of the same parts as in the first embodiment is omitted, and only the different parts are described. The fourth embodiment has a configuration in which the main microcomputer 2 and the external cooperation device 13 communicate with each other via an I2C (Inter-Integrated Circuit). That is, the main microcomputer 2 and the external cooperation device 13 perform data communication over a clock line and a data line.

[0040] As it is in Fig.As can be seen in Figure 9, a supply voltage control circuit 51 is provided between the main microcomputer 2 and the external cooperation device 13. An N-channel FET (field-effect transistor) 52 (switching element) is inserted in the clock line connecting the main microcomputer 2 and the external cooperation device 13. The clock line on the main microcomputer 2 side is connected to the source terminal of the N-channel FET 52 and is also connected to the voltage generation circuit 18 via the pull-up resistor 53. The gate terminal of the N-channel FET 52 is connected to the voltage generation circuit 18. The drain terminal of the N-channel type FET 52 is connected to the clock line on the side of the external cooperation device 13 and is also connected to the voltage generation circuit 20 via the pull-up resistor 54 and the diode 58.An N-channel FET 55 (switching element) is inserted into the data line connecting the main microcomputer 2 and the external cooperation device 13. The data line on the main microcomputer 2 side is connected to the source terminal of the N-channel FET 55 and is also connected to the voltage generation circuit 18 via the pull-up resistor 56. The gate terminal of the N-channel FET 55 is connected to the voltage generation circuit 18. The drain terminal of the N-channel FET 55 is connected to the data line on the external cooperation device 13 side and is also connected to the voltage generation circuit 20 via the pull-up resistor 57 and the diode 58. The diode 58 prevents the clock signal from being fed to the voltage generation circuit 20.

[0041] According to the fourth embodiment, even in a configuration where the main microcomputer 2 and the external cooperation device 13 perform the I2C communication, the same effects as those described in the first embodiment above can be obtained. (Other embodiments)

[0042] Although the present disclosure has been described in accordance with the examples, it shall be understood that the present disclosure is not limited to such examples or structures. The present disclosure includes various modifications and variations within the scope of equivalents. In addition, various combinations and configurations, as well as other combinations and configurations containing more, less, or only a single element, are within the scope and meaning of the present disclosure. The first characteristic device is not limited to the safety and security device that provides the safety and security function and may be a device that provides other functions.The second characteristic device is not limited to the multimedia device that provides the multimedia function and may be a device that provides other functions.

[0043] The control device and method thereof described in the present disclosure can be implemented (i) by (a) a first special-purpose computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program product, or (ii) by (b) a second special-purpose computer provided by configuring a processor with one or more special-purpose hardware logic circuits, or (iii) any combination of (a) the first special-purpose computer provided by configuring the processor and memory, and (b) the second special-purpose computer provided by configuring the processor with one or more special-purpose hardware logic circuits.The computer program can also be stored on a computer-readable, non-perishable tangible storage medium as instructions to be executed by a computer.

Claims

[1] Vehicle control apparatus comprising: a first characteristic device (5) configured to provide a first characteristic function, a second characteristic device (6) configured to provide a second characteristic function, a control device (2, 32) configured to output a control signal to each of the devices, first characteristic device and second characteristic device, via a signal line, and a supply voltage control device (22, 33, 42, 51) which is provided between the control device and the second characteristic device, where: a minimum operating voltage of the first characteristic device is set to be lower than a minimum operating voltage of the second characteristic device, the supply voltage control device is configured to prevent a situation in which a supply voltage of a device power supplied to the second characteristic device becomes less than an input voltage of the signal line of the control signal transmitted from the control device to the second characteristic device. the first characteristic device includes a safety and security device configured to provide, as the function of the first characteristic, a safety and security function necessary to provide safety and security rather than mere amenity and comfort, and The second characteristic device includes a multimedia device configured to provide a multimedia function as the function of the second characteristic, which is not required to provide as much safety and security as the safety and security function. [2] Vehicle control apparatus comprising: a first characteristic device (5) configured to provide a first characteristic function, a second characteristic device (6) configured to provide a second characteristic function, a control device (2, 32) configured to output a control signal to each of the devices, first characteristic device and second characteristic device, via a signal line, and a supply voltage control device (22, 33, 42, 51) which is provided between the control device and the second characteristic device, where: a minimum operating voltage of the first characteristic device is set to be lower than a minimum operating voltage of the second characteristic device, the supply voltage control device is configured to prevent a situation in which a supply voltage of a device power supplied to the second characteristic device becomes less than an input voltage of the signal line of the control signal transmitted from the control device to the second characteristic device, and the supply voltage control device (22, 33) includes a buffer circuit (23, 34) and a pull-up resistor (26). [3] Vehicle control apparatus according to claim 2, wherein: the buffer circuit (34) is included in the control device (32). [4] Vehicle control apparatus according to claim 1, wherein: the supply voltage control device (42) includes a level converter circuit (43). [5] Vehicle control apparatus comprising: a first characteristic device (5) configured to provide a first characteristic function, a second characteristic device (6) configured to provide a second characteristic function, a control device (2, 32) configured to output a control signal to each of the devices, first characteristic device and second characteristic device, via a signal line, and a supply voltage control device (22, 33, 42, 51) which is provided between the control device and the second characteristic device, where: a minimum operating voltage of the first characteristic device is set to be lower than a minimum operating voltage of the second characteristic device, the supply voltage control device is configured to prevent a situation in which a supply voltage of a device power supplied to the second characteristic device becomes less than an input voltage of the signal line of the control signal transmitted from the control device to the second characteristic device. the control device and the second characteristic device are configured to perform data communication over a clock line and a data line, and the supply voltage control device (51) (i) includes a switching element (52) and a pull-up resistor (53, 54) connected to the clock line, and (ii) a switching element (55) and a pull-up resistor (56, 57) connected to the data line.

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