JP7838513B2 - In-vehicle device, information processing method, and program - Google Patents

Description

This technology relates to in-vehicle devices, information processing methods, and programs.

The vehicle is equipped with a power supply control device (see, for example, Patent Document 1) that controls the supply of power from the battery to the load. In the power supply control device described in Patent Document 1, a downstream semiconductor fuse is provided in the current path of the current flowing from the battery to the load, and the power supply from the battery to the load is controlled by switching the downstream semiconductor fuse on or off.

Japanese Patent Publication No. 2013-143905

However, the power supply control device described in Patent Document 1 does not take into consideration the fact that the tripping characteristics of the semiconductor fuse are changed according to the vehicle's power consumption state.

This disclosure is made in view of the circumstances described above, and aims to provide an in-vehicle device, etc., that can change the interruption characteristics of a semiconductor fuse according to the power consumption state of the vehicle.

An in-vehicle device according to one embodiment of this disclosure is an in-vehicle device that controls the opening and closing of a plurality of semiconductor fuses provided in a power line from a power supply device mounted on a vehicle, and comprises a control unit that performs processing related to the opening and closing control of the semiconductor fuses, wherein the semiconductor fuses include a main line semiconductor fuse arranged on the main line and each branch line semiconductor fuse arranged on each of the branch lines branching off from the main line, and the control unit acquires information regarding the power consumption state of the vehicle, and activates the protection function of the main line semiconductor fuse and deactivates the protection function of the branch line semiconductor fuse according to the acquired information regarding the power consumption state of the vehicle.

According to one aspect of this disclosure, it is possible to provide an in-vehicle device, etc., that changes the interruption characteristics of a semiconductor fuse according to the power consumption state of the vehicle.

This is a schematic diagram illustrating the configuration of an in-vehicle system including an in-vehicle device according to Embodiment 1. This is a block diagram illustrating the internal configuration of an in-vehicle device. This is an explanatory diagram illustrating the setting of the interruption characteristics of semiconductor fuses for main lines. This is a flowchart illustrating the processing of the control unit of an in-vehicle device.

[Description of Embodiments of the Invention]
First, embodiments of this disclosure will be listed and described. Furthermore, at least some of the embodiments described below may be combined in any way.

(1) An in-vehicle device according to one aspect of the present disclosure is an in-vehicle device that controls the opening and closing of a plurality of semiconductor fuses provided in a power line from a power supply device mounted on a vehicle, and comprises a control unit that performs processing related to the opening and closing control of the semiconductor fuses, wherein the semiconductor fuses include a main line semiconductor fuse arranged on the main line and each branch line semiconductor fuse arranged on each of the branch lines branching off from the main line, and the control unit acquires information regarding the power consumption state of the vehicle, and activates the protection function of the main line semiconductor fuse and deactivates the protection function of the branch line semiconductor fuse according to the acquired information regarding the power consumption state of the vehicle.

In this embodiment, the control unit of the in-vehicle device controls the opening and closing of a semiconductor fuse provided on the power line from the power supply unit. When an overcurrent flows through the power line, the control unit turns off (opens) the semiconductor fuse according to the interruption characteristics defined for the semiconductor fuse, thereby interrupting the overcurrent. If an in-vehicle load such as an actuator is connected to the semiconductor fuse, the control unit of the in-vehicle device may control the semiconductor fuse on and off (open/close) in response to a drive request for the in-vehicle load. The semiconductor fuse includes a main line semiconductor fuse located on the main line and each of the branch line semiconductor fuses located on each of the branch lines branching off from the main line. In the direction of current flow from the power supply unit, the main line semiconductor fuse is located upstream, and each of the branch line semiconductor fuses is located downstream of the main line semiconductor fuse. The semiconductor fuse, including the main line semiconductor fuse and the branch line semiconductor fuses, is turned off (open) by the control unit when an overcurrent flows for a predetermined period of time or longer, according to the set interruption characteristics, thereby exhibiting a protective function that interrupts the overcurrent. Furthermore, semiconductor fuses, including main line semiconductor fuses and branch line semiconductor fuses, may be controlled by the control unit to open and close (on/off control), thereby starting or stopping the power supply to the on-board load connected to the semiconductor fuse, and performing drive control of the on-board load (exhibiting a drive control function). The control unit of the on-board device acquires information regarding the vehicle's power consumption status by acquiring signals from, for example, an IG switch or power switch that controls the starting and stopping of the vehicle. Alternatively, the control unit of the on-board device may acquire information regarding the vehicle's power consumption status by acquiring, for example, information regarding vehicle speed, information regarding the rotation of the engine or drive motor, etc., from an on-board ECU connected to the on-board network. Thus, the vehicle's power consumption status may indicate the state of power consumed in the vehicle depending on whether the vehicle is in a driving state (started state) or a parked state (stopped state). Based on the information regarding the vehicle's power consumption status, the control unit of the on-board device activates the protection function of the main line semiconductor fuse and deactivates the protection function of each branch line semiconductor fuse located in each of the multiple branch lines. In other words, depending on the vehicle's power consumption state, the protection function of the main semiconductor fuse can be used to protect the main line and the multiple branch lines branching off from the main line, thus ensuring safety as an in-vehicle system. By disabling each of the branch line semiconductor fuses, the dark current required for the branch line semiconductor fuses to perform their protective function can be reduced. This reduces the vehicle's power consumption, especially in standby states (low power consumption mode) such as when parked.

(2) In one aspect of the present disclosure, the in-vehicle device, when activating the protective function of the main line semiconductor fuse, has the control unit set the interruption characteristics of the main line semiconductor fuse such that they are below the smoke emission characteristics corresponding to the multiple branch lines and exceed the sum of the current values flowing through the multiple branch lines when the vehicle is in standby mode.

In this embodiment, the control unit of the in-vehicle device, in activating the protection function of the main line semiconductor fuse, sets the interruption characteristics of the main line semiconductor fuse to be lower than the smoke emission characteristics corresponding to the multiple branch lines, and higher than the sum of the current values flowing through the multiple branch lines when the vehicle is in standby mode. The smoke emission characteristics corresponding to the multiple branch lines are, for example, the sum of the smoke emission characteristics of each of these branch lines. Alternatively, the smoke emission characteristics corresponding to the multiple branch lines may be the sum of the smoke emission characteristics of each of the in-vehicle loads (devices) such as sensors or actuators connected to each of these branch lines. The sum of the current values flowing through the multiple branch lines when the vehicle is in standby mode may be a predetermined assumed value used as the maximum current value flowing through the main line in that standby state. If the interruption characteristics of the main semiconductor fuse are set to, for example, an initial value (initial setting), or to a normal state (normal current mode) where a relatively large current flows through the main line, the control unit of the on-board device may change the interruption characteristics from the initial setting so that they are below the smoke emission characteristics and above the sum of the current values. When the vehicle is in standby mode, the lower limit of the current value determined according to the smoke emission characteristics for each branch line is assumed to be, for example, about 10 times the sum of the current values flowing through each branch line. In such a case, the setting range of the interruption characteristics can be made relatively wide by setting the smoke emission characteristics for each branch line as the upper limit and the sum of the current values flowing through each branch line when the vehicle is in standby mode as the lower limit. In this case, the tripping characteristics of the main semiconductor fuse in standby mode (low current consumption mode) may be set to a value near the midpoint (midrange) between the smoke emission characteristics corresponding to multiple branch lines and the sum of the current values flowing through the multiple branch lines when the vehicle is in standby mode. Therefore, for example, by setting the tripping characteristics of the main semiconductor fuse to a value near the midpoint (midrange), the influence of errors in current value detection during on-resistance or tripping control by the main semiconductor fuse can be reduced, resulting in a relatively robust control method that efficiently ensures safety as an in-vehicle system.

(3) In one aspect of the present disclosure, the vehicle's power consumption state includes a normal state and a standby state in which power consumption is lower than that of the normal state. The control unit, when the acquired information regarding the vehicle's power consumption state indicates the standby state, activates the protection function of the main semiconductor fuse and deactivates the protection function of the branch line semiconductor fuse. When the acquired information regarding the vehicle's power consumption state indicates the normal state, it deactivates the protection function of the main semiconductor fuse and activates the protection function of the branch line semiconductor fuse.

In this embodiment, the vehicle's power consumption state includes a normal state and a standby state (low current consumption mode) in which power consumption is lower than that of the normal state (normal current mode). The normal state includes, for example, the state in which the vehicle is running (starting up), and may indicate a state in which the vehicle's power consumption is above a predetermined value (normal current mode). The standby state includes, for example, the state in which the vehicle is parked (stopped), and may indicate a state in which the vehicle's power consumption is below a predetermined value (low current consumption mode). If the acquired information regarding the vehicle's power consumption state indicates a normal state (the vehicle is in a normal state), the control unit disables the protection function of the main semiconductor fuse and enables the protection function of the branch line semiconductor fuse. If the acquired information regarding the vehicle's power consumption state indicates a standby state (the vehicle is in a standby state), the control unit enables the protection function of the main semiconductor fuse and disables the protection function of the branch line semiconductor fuse. In this way, by complementaryly enabling or deactivating the main line semiconductor fuse and the branch line semiconductor fuse according to the vehicle's power consumption state (normal state or standby state), the power consumption required for controlling the deactivated semiconductor fuse (main line semiconductor fuse or branch line semiconductor fuse) can be reduced. By providing main line semiconductor fuses and branch line semiconductor fuses that are controlled in this complementary manner, the design and implementation flexibility of a configuration that reduces dark current in standby states (low current consumption mode) such as when parked can be improved.

(4) An in-vehicle device according to one aspect of the present disclosure includes a mechanical relay connected in parallel to the main semiconductor fuse, and the control unit maintains the mechanical relay in an open state when the vehicle is in standby mode.

In this embodiment, the on-board device includes a mechanical relay connected in parallel to the main semiconductor fuse. That is, the main line, which forms part of the power line extending from a power supply device such as a lead-acid battery, includes a main line on which the semiconductor fuse is located and a main line on which the mechanical relay is located, forming a parallel circuit between the main line of the semiconductor fuse and the main line of the mechanical relay. A fuse (fusible fuse) may also be located on the main line on which the mechanical relay is located. In this case, the mechanical relay and the fuse (fusible fuse) are connected in series on the main line. The control unit of the on-board device maintains the mechanical relay in the open state (off) when the vehicle is in a standby state (low current consumption mode), such as when the vehicle is parked. This eliminates the need for the mechanical relay to open and close during standby, thereby improving the number of cycles (usable period, component life) of the mechanical relay.

(5) In one embodiment of the present disclosure, the in-vehicle device includes a control unit which acquires the current value flowing through the main line where the main line semiconductor fuse is located, and which performs tripping control on the main line semiconductor fuse based on the acquired current value, with tripping characteristics set according to the standby state.

In this embodiment, the control unit of the in-vehicle device acquires the current value flowing through the main line from a current detection unit that detects the current flowing through the main line on which a main line semiconductor fuse is located. The current detection unit is composed of, for example, a shunt resistor provided on the main line on which the main line semiconductor fuse is located. Alternatively, if the main line semiconductor fuse is composed of, for example, an IPD (Intelligent Power Device), the current detection unit built into the IPD may be used. Based on the current value detected by the current detection unit, the control unit of the in-vehicle device performs tripping control on the main line semiconductor fuse according to the tripping characteristics set according to the standby state. The tripping characteristics may be shown as a tripping characteristic curve in a characteristic graph with the vertical axis representing the current value (A) and the horizontal axis representing the elapsed time (S), and the tripping characteristic curve may be stored in a memory unit. The control unit of the in-vehicle device refers to the interruption characteristic curve stored in the memory unit and, according to the current value detected by the current detection unit and the elapsed time, opens (turns off) the main line semiconductor fuse to interrupt the current (overcurrent) flowing through the main line. Even if the protection functions of the branch line semiconductor fuses directly connected to individual in-vehicle devices such as actuators are disabled in standby mode (low current consumption mode), such as when parked, interruption control can be performed using the main line semiconductor fuse, which has interruption characteristics set according to the standby state. This allows for efficient safety assurance of the in-vehicle system while reducing dark current in standby mode (low current consumption mode).

(6) A program according to one aspect of the present disclosure is a program that causes a computer to perform processing to control the opening and closing of multiple semiconductor fuses provided in the power lines from a power supply device mounted on a vehicle, wherein the semiconductor fuses include a main line semiconductor fuse arranged on the main line and each branch line semiconductor fuse arranged on each of the branch lines branching off from the main line, and the program acquires information regarding the power consumption status of the vehicle, and, according to the acquired information regarding the power consumption status of the vehicle, performs processing to activate the protection function of the main line semiconductor fuse and deactivate the protection function of the branch line semiconductor fuses.

In this embodiment, a program can be provided that causes the computer to function as an in-vehicle device that changes the interruption characteristics of the main semiconductor fuse according to the vehicle's power consumption status.

(7) An information processing method according to one aspect of the present disclosure is an information processing method that causes a computer to perform processing for controlling the opening and closing of a plurality of semiconductor fuses provided in a power line from a power supply device mounted on a vehicle, wherein the semiconductor fuses include a main line semiconductor fuse arranged on the main line and each branch line semiconductor fuse arranged on each of the branch lines branching off from the main line, and the method acquires information regarding the power consumption state of the vehicle, and, according to the acquired information regarding the power consumption state of the vehicle, performs processing to activate the protection function of the main line semiconductor fuse and deactivate the protection function of the branch line semiconductor fuses.

In this embodiment, an information processing method is provided that causes a computer to function as an in-vehicle device that changes the interruption characteristics of a main-line semiconductor fuse according to the vehicle's power consumption status.

[Details of the embodiments of this disclosure]
This disclosure will be described in detail with reference to the drawings illustrating its embodiments. An in-vehicle device 1 according to an embodiment of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited to these examples and is intended to include all modifications within the meaning and scope of the claims, as indicated by the claims.

(Embodiment 1)
The embodiments will be described below with reference to the drawings. Figure 1 is a schematic diagram illustrating the configuration of an in-vehicle system S including an in-vehicle device 1 according to Embodiment 1. Figure 2 is a block diagram illustrating the internal configuration of the in-vehicle device 1. The in-vehicle system S consists of an in-vehicle device 1 mounted on a vehicle C, an in-vehicle ECU 2, and an in-vehicle network 3 that connects them in a communicative manner. The in-vehicle network 3 consists of a plurality of communication lines 31. When communication in the in-vehicle network 3 is performed according to a communication protocol such as CAN (Controller Area Network) or CAN-FD, the communication lines 31 correspond to a CAN bus.

Vehicle C is equipped with a power supply unit 5, which consists of a lead-acid battery, alternator, or secondary battery. The power supply unit 5 and the on-board device 1 are connected by a power line 51. The connection between the power supply unit 5 and the on-board device 1 is not limited to a direct connection via the power line 51; an electrical box (junction box) such as a relay box or fuse box 521 box may be interposed between the power supply unit 5 and the on-board device 1, resulting in an indirect connection.

The on-board device 1 and the multiple on-board loads 6 or on-board ECUs 2 are connected by a power line 51 (branch line 512), and the on-board device 1 distributes power to these multiple on-board loads 6 or on-board ECUs 2. In other words, the on-board device 1 functions as a power distribution device, distributing the power supplied from the power supply device 5 via the power line 51 to the multiple on-board loads 6 or on-board ECUs 2 located downstream in the direction of current flow.

The power line 51 extending from the power supply unit 5 is connected to the main semiconductor fuse 531 provided in the on-board device 1. The power line 51 is located inside the on-board device 1 and includes a main line 511 to which the main semiconductor fuse 531 is connected, and a plurality of branch lines 512 branching off from the main line 511. The main line 511 includes the main line 511 to which the main semiconductor fuse 531 is connected, and the main line 511 to which the fuse 521 (fusible fuse) and mechanical relay 52 are connected. The main line 511 of the main semiconductor fuse 531 and the main line 511 of the fuse 521 (fusible fuse), etc., constitute a parallel circuit. That is, the main semiconductor fuse 531, the fuse 521 (fusible fuse), and the mechanical relay 52 are connected in parallel.

A current detection unit 513 is positioned between the main semiconductor fuse 531 and the branching point where the main line 511 branches into multiple branch lines 512. The current detection unit 513 may be located on the main line 511 where the main semiconductor fuse 531 is positioned. The current detection unit 513 periodically or continuously detects the value of the current flowing through the main semiconductor fuse 531. The current detection unit 513 is a current sensor, for example, composed of a shunt resistor, and outputs the detected current value to the control unit 11 of the in-vehicle device 1. Alternatively, the current detection unit 513 may be a current sensor (main current sensor) built into the IPD (Intelligent Power Device) that constitutes the main semiconductor fuse 531.

Each of the multiple branch lines 512 is equipped with a branch line semiconductor fuse 532. The branch line semiconductor fuse 532 is, for example, composed of an IPD (Intelligent Power Device). These branch line semiconductor fuses 532 are positioned downstream of the main line semiconductor fuse 531 in the direction of current flow from the power line 51. The branch lines 512 located downstream of the branch line semiconductor fuse 532 in the direction of current flow from the power line 51 are connected to the vehicle load 6 or the vehicle ECU 2.

The vehicle load 6 is, for example, an actuator such as a car air conditioner, lamp, or drive motor. The vehicle ECU 2 includes a microcontroller with communication capabilities and performs predetermined calculations based on detected values from sensors or output values from various switches. These vehicle loads 6, etc., are started or stopped by the opening and closing control (on/off control) of the semiconductor fuse 532 for the branch line located in the branch line 512. The vehicle device 1 functions as a power control device that controls the starting or stopping of the vehicle loads 6, etc., by performing the opening and closing control (on/off control) of these semiconductor fuses 532 for the branch line.

The on-board device 1 functions as a power control device that controls the startup or shutdown of the on-board ECU 2, and may be a device with relay functions, such as a CAN gateway. Alternatively, the on-board device 1 may be an integrated ECU (vehicle computer) that comprehensively controls the entire vehicle C and has relay functions. Alternatively, the on-board device 1 may be individual ECUs connected under the integrated ECU and located in each area of the vehicle C. Alternatively, the on-board device 1 may be configured as a body ECU that controls the body system actuators of the vehicle C. Alternatively, the on-board device 1 may be a PLB (Power LAN Box) that, in addition to relaying communications, also functions as a power distribution device that distributes and relays power output from a power supply device 5, such as a secondary battery, and supplies power to on-board equipment such as actuators. Various on-board devices such as switches, sensors, or actuators may be connected to the on-board device 1.

The in-vehicle device 1 includes a control unit 11, a storage unit 12, a communication unit 13, and an input/output interface 14. The control unit 11 is composed of a CPU (Central Processing Unit) or MPU (Micro Processing Unit), and performs various control and calculation processes by reading and executing control programs P (program products) and data pre-stored in the storage unit 12.

The storage unit 12 is composed of volatile memory elements such as RAM (Random Access Memory), non-volatile memory elements such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable ROM), or flash memory, or a combination of these storage devices, and pre-stores the control program P (program product) and data referenced during processing. The control program P (program product) stored in the storage unit 12 may be one read from a recording medium M accessible to the in-vehicle device 1. Alternatively, the control program P (program product) may be downloaded from an external computer (not shown) connected to a communication network (not shown) and stored in the storage unit 12.

The communication unit 13 is an input/output interface using a communication protocol such as CAN, CAN-FD, or Ethernet (Ethernet/registered trademark). The control unit 11 communicates with the in-vehicle ECU 2, which is connected to the in-vehicle network 3, via the communication unit 13. In the in-vehicle device 1, multiple communication units 13 may be provided.

The input/output interface 14 is, for example, a communication interface for serial communication. The input/output interface 14 includes multiple terminals (output terminals), each connected to a signal line 140 extending from the main semiconductor fuse 531, the current detection unit 513, the mechanical relay 52, and the branch line semiconductor fuse 532, respectively. The signal line 140 is composed of, for example, a serial cable, a wire harness, or a conductive cable (direct wire) that transmits only one signal.

The main line semiconductor fuse 531 is, for example, composed of an FET (Field Effect Transistor). Alternatively, the main line semiconductor fuse 531 may be composed of an IPD (Integrated Power Distribution) including the FET. The control unit 11 of the in-vehicle device 1 controls the tripping of the main line semiconductor fuse 531 based on the current value output from the current detection unit 513, according to the tripping characteristics of the main line semiconductor fuse 531. As will be described in detail later, the tripping characteristics of the main line semiconductor fuse 531 are variably set according to the power consumption state of the vehicle C (normal state or standby state).

The semiconductor fuse 532 for the branch line is, for example, made of an FET (Field Effect Transistor). Alternatively, the semiconductor fuse 532 for the branch line may be made of an IPD that includes the FET or the like. The control unit 11 of the in-vehicle device 1 controls the tripping of the semiconductor fuse 532 for the branch line based on the current value output from a current sensor (branch line 512 current sensor) or the like that built into the IPD that constitutes the semiconductor fuse 532 for the branch line , according to the tripping characteristics of the semiconductor fuse 532 for the branch line .

Figure 3 is an explanatory diagram illustrating the setting of the interruption characteristics of the main line semiconductor fuse 531. The interruption characteristics of the main line semiconductor fuse 531 and the smoke emission characteristics of the branch line 512 are both shown on a characteristic graph with the vertical axis representing current value (A) and the horizontal axis representing elapsed time (S).

The interruption characteristic defines the time it takes for a semiconductor fuse (such as the main line semiconductor fuse 531 or the branch line semiconductor fuse 532) to interrupt the current when an overcurrent exceeding its rated current value flows through it (corresponding to the melting time in fuse 521). If the current flowing through the semiconductor fuse is less than or equal to the rated current value, the semiconductor fuse will not interrupt and will continue to allow a current of that value or less to flow.

The semiconductor fuse 531 for the main line is configured with interruption characteristics corresponding to the standby state (low current consumption mode). The semiconductor fuse 532 for the branch lines is configured with interruption characteristics corresponding to the normal state (normal current mode). Details of these standby state (low current consumption mode) and normal state (normal current mode) will be described later.

The interruption characteristics of the main semiconductor fuse 531 may be set by the control unit 11 of the on-board device 1 as a variable characteristic value that allows the current value to be moved up or down in the vertical axis direction, i.e., for the same elapsed time. When the interruption characteristics of the main semiconductor fuse 531 are high, the rated current value is also high, and the time until interruption in the event of an overcurrent is also longer. When the interruption characteristics of the main semiconductor fuse 531 are low, the rated current value is also lower, and the time until interruption in the event of an overcurrent is shortened. In other words, the product of the current value (overcurrent value) and the time until interruption (integrated current value) fluctuates depending on the level of the interruption characteristics.

The tripping characteristics of the main semiconductor fuse 531 in standby mode (fuse tripping characteristics in low current consumption mode) are set to be lower than the sum of the smoke emission characteristics (sum of device characteristics) of the branch lines 512 into which the main line 511 branches or the smoke emission characteristics (device characteristics) of the vehicle loads connected to the branch lines 512 (downstream smoke emission characteristics/device characteristics), by applying, for example, a predetermined offset value. Furthermore, the tripping characteristics of the main semiconductor fuse 531 in standby mode (fuse tripping characteristics in low current consumption mode) are set to be higher than the sum of the current values flowing through each of the branch lines 512 into which the main line 511 branches in standby mode (for example, the sum of the current consumption when parked).

In other words, the tripping characteristics of the main line semiconductor fuse 531 in the standby state (fuse tripping characteristics in low current consumption mode) are set to be lower than the smoke emission characteristics corresponding to the multiple branch lines 512, and higher than the sum of the current values (combined values) flowing through the multiple branch lines 512 when vehicle C is in standby mode. This allows for tripping control according to the tripping characteristics of the main line semiconductor fuse 531 in the standby state without exceeding the allowable values defined by the smoke emission characteristics or device characteristics of the multiple branch lines 512, etc., thereby reliably protecting the multiple branch lines 512, etc., from overcurrent.

The interruption characteristics of the main semiconductor fuse 531 in the standby state (fuse interruption characteristics in low current consumption mode) are set to be lower than those of the fuse 521 (fusible fuse) in the normal state (fuse interruption characteristics in normal current mode (mechanical relay)). In the normal state, the interruption characteristics of the main semiconductor fuse 531 may be set (changed) to be the same as those of the fuse 521 (fusible fuse) (fuse interruption characteristics in normal current mode (mechanical relay)). In this case, the protection function of the main semiconductor fuse 531 is always enabled, and the interruption characteristics of the main semiconductor fuse 531 are changed to either the standby state interruption characteristics or the normal state interruption characteristics depending on the power consumption state of vehicle C. As a result, under normal conditions, the fuse 521 (fusible fuse), the mechanical relay 52, and the main line semiconductor fuse 531 are connected in parallel and have the same interrupting characteristics, thus providing redundancy through a parallel circuit of the fuse 521 (fusible fuse), the mechanical relay 52, and the main line semiconductor fuse 531. Furthermore, the interrupting characteristics of the main line semiconductor fuse 531 in standby mode (fuse interrupting characteristics in low current consumption mode) are set to be lower than the interrupting characteristics of the branch line semiconductor fuse 532 in normal conditions (interrupting characteristics of downstream semiconductor fuses).

Figure 4 is a flowchart illustrating the processing of the control unit 11 of the in-vehicle device 1. The control unit 11 of the in-vehicle device 1 routinely performs the following processing when the vehicle C is stopped or started.

The control unit 11 of the on-board device 1 acquires information regarding the power consumption status of vehicle C (S101). The control unit 11 of the on-board device 1 determines whether vehicle C is in an active or stopped state by acquiring signals, for example, from the IG switch or power switch that controls the starting and stopping of vehicle C. Alternatively, the control unit 11 of the on-board device 1 may determine whether the vehicle speed is 0 by acquiring information, for example, information regarding vehicle speed, information regarding the rotation of the engine or drive motor, etc., from the on-board ECU 2 connected to the on-board network 3. The control unit 11 of the on-board device 1 may derive (acquire) information regarding the power consumption status of vehicle C depending on whether vehicle C is in a driving state (active state) or a parked state (stopped state). That is, the information regarding the power consumption status of vehicle C includes information indicating whether vehicle C is in an active or stopped state.

The power consumption state of vehicle C includes a normal state (normal current mode) and a standby state (low current consumption mode) where power consumption is lower than that of the normal state. The normal state includes, for example, the state when vehicle C is running (starting up), and indicates a state where vehicle C's power consumption is above a predetermined value (normal current mode). The standby state includes, for example, the state when vehicle C is parked (stopped), and indicates a state where vehicle C's power consumption is below a predetermined value (low current consumption mode).

Alternatively, the normal state (normal current mode) may include the state in which vehicle C is in motion or parked with occupants, and may indicate a state in which the engine is running and any on-board load is being driven. The standby state (low current consumption mode) may include the state in which the vehicle is parked without occupants, and may indicate a state in which the engine is not running and none of the on-board loads are being driven. However, the on-board loads are not necessarily in a completely stopped state; for example, they may be in a state where they can be driven immediately upon receiving a predetermined start signal. That is, the standby state also includes the state in which such on-board loads or on-board ECU 2 are in a state where they can be driven immediately.

The storage unit 12 of the in-vehicle device 1 may store state definition information, for example in a table format (lookup table), that defines the correspondence between the state of the vehicle C or the in-vehicle load and the power consumption state (normal state or standby state). The control unit 11 of the in-vehicle device 1 may derive (acquire) the power consumption state of the vehicle C by referring to this state definition information (lookup table). The control unit 11 of the in-vehicle device 1 acquires this information by deriving information related to the power consumption state of the vehicle C based on signals received from various switches, or communication data such as messages received from the in-vehicle ECU 2, which is connected to the in-vehicle network 3.

The control unit 11 of the on-board device 1 determines whether vehicle C is in a standby state or not based on information regarding the power consumption status of vehicle C (S102). Based on the acquired information regarding the power consumption status of vehicle C, the control unit 11 of the on-board device 1 determines whether vehicle C is in a standby state (low current consumption mode) or a normal state (normal current mode). The control unit 11 of the on-board device 1 may store this determination result in the storage unit 12, associated with the time the determination process was performed (determination time).

If vehicle C is in standby mode (S102: YES), the control unit 11 of the on-board device 1 sets the main semiconductor fuse 531 to the tripping characteristics corresponding to the standby mode and activates the protection function (S103). The control unit 11 of the on-board device 1 sets the main semiconductor fuse 531 to the tripping characteristics corresponding to the standby mode when vehicle C is in standby mode (low current consumption mode). The tripping characteristics of the main semiconductor fuse 531 according to the standby mode are shown, for example, as a tripping characteristic curve in a characteristic graph and stored in the storage unit 12.

The control unit 11 of the in-vehicle device 1 may activate the protection function of the main semiconductor fuse 531 by applying the said tripping characteristics when executing an application corresponding to the protection function of the main semiconductor fuse 531. Alternatively, if the main semiconductor fuse 531 is configured as, for example, an IPD (Intelligent Power Device), the control unit 11 may activate the protection function of the main semiconductor fuse 531 by transmitting a signal to the IPD (main semiconductor fuse 531) to initiate (activate) the protection function by applying tripping characteristics corresponding to the standby state.

The control unit 11 of the in-vehicle device 1 may further maintain the mechanical relay 52 in the open state (off) (fixed off) when the vehicle C is in a standby state (low current consumption mode). By maintaining the mechanical relay 52 in the open state (off) (fixed off) when the vehicle C is in a standby state (low current consumption mode), the opening and closing operation of the mechanical relay 52 in that standby state becomes unnecessary, thereby improving the number of cycles (usable period, component life) of the mechanical relay 52.

The control unit 11 of the in-vehicle device 1 disables the protection function of the branch line semiconductor fuse 532 (S104). The control unit 11 of the in-vehicle device 1 may disable the protection function of the branch line semiconductor fuse 532 by, for example, stopping the application corresponding to the protection function of the branch line semiconductor fuse 532. Alternatively, if the branch line semiconductor fuse 532 is configured as, for example, an IPD (Intelligent Power Device), the protection function of the branch line semiconductor fuse 532 may be disabled by transmitting a signal to the IPD (branch line semiconductor fuse 532) to stop (disable) its protection function.

By disabling the protection function of the semiconductor fuse 532 for branch lines in this way, the power consumption required to activate (execute) the protection function can be reduced. In other words, the more semiconductor fuses 532 for branch lines whose protection function is disabled in the standby state (low current consumption mode) (three in this embodiment), the greater the power consumption reduction effect.

The control unit 11 of the in-vehicle device 1, when enabling or disabling the protection functions of the main line semiconductor fuse 531 and the branch line semiconductor fuse 532, first enables the protection function of the main line semiconductor fuse 531, and then disables the protection function of the branch line semiconductor fuse 532. This ensures that when vehicle C transitions to a standby state, the protection function of the main line semiconductor fuse 531 is enabled first, thereby reliably preventing a period during which both the main line semiconductor fuse 531 and the branch line semiconductor fuse 532 protection functions are disabled.

The control unit 11 of the in-vehicle device 1 starts tripping control for the main semiconductor fuse 531, which has tripping characteristics set according to the standby state (S105). The tripping characteristics set for the main semiconductor fuse 531 according to the standby state are lower than the smoke emission characteristics corresponding to the multiple branch lines 512, and higher than the sum of the current values (combined value) flowing through the multiple branch lines 512 when the vehicle C is in standby state (tripping characteristics). If the current value (overcurrent) determined by the smoke emission characteristics corresponding to the multiple branch lines 512 is set as the upper limit and the sum of the current values (combined value) flowing through the multiple branch lines 512 when the vehicle C is in standby state is set as the lower limit, the range of current values determined by these upper and lower limits is relatively wide. The tripping characteristics of the main semiconductor fuse 531 in standby state only need to be within the range of current values determined by these upper and lower limits, and therefore, the degree of freedom when setting the tripping characteristics can be increased. This reduces the influence of errors in the on-resistance of the main semiconductor fuse 531 or in current value detection during the interruption control process when setting the interruption characteristics of the main semiconductor fuse 531 in the standby state, resulting in a relatively robust control method that efficiently ensures safety as an in-vehicle system S.

The control unit 11 of the in-vehicle device 1 is connected in series with the main semiconductor fuse 531 and obtains the current value of the current flowing through the main line 511 from the current detection unit 513 (main current sensor) located on the main line 511. Alternatively, the current value of the current flowing through the main line 511 may be obtained from the main current sensor built into the IPD (Integrated Power Distribution) constituting the main semiconductor fuse 531. Based on the interruption characteristic curve (interruption characteristic according to the standby state) stored in the memory unit 12, the control unit 11 of the in-vehicle device 1 opens the main semiconductor fuse 531 (turns it off) and interrupts the current (overcurrent) flowing through the main line 511 if a current value corresponding to an overcurrent flows for a predetermined period of time or longer.

If vehicle C is not in standby mode (S102: NO), i.e., if vehicle C is in normal mode, the control unit 11 of the on-board device 1 activates the protection function of the branch line semiconductor fuse 532 (S1021). If vehicle C is not in standby mode, i.e., if vehicle C is in normal mode (normal current mode), the control unit 11 of the on-board device 1 may activate the protection function of the branch line semiconductor fuse 532 by executing an application corresponding to the protection function of the branch line semiconductor fuse 532. Alternatively, if the branch line semiconductor fuse 532 is configured as, for example, an IPD (Intelligent Power Device), the protection function of the branch line semiconductor fuse 532 may be activated by transmitting a signal to the IPD (branch line semiconductor fuse 532) to initiate (activate) the protection function.

The control unit 11 of the in-vehicle device 1 disables the protection function of the main semiconductor fuse 531 (S1022). The control unit 11 of the in-vehicle device 1 may also disable the protection function of the main semiconductor fuse 531 by stopping the application corresponding to the protection function of the main semiconductor fuse 531. Alternatively, if the main semiconductor fuse 531 is configured as, for example, an IPD (Intelligent Power Device), the protection function of the main semiconductor fuse 531 may be disabled by transmitting a signal to the IPD (main semiconductor fuse 531) to stop (disable) its protection function.

The control unit 11 of the in-vehicle device 1, when enabling or disabling the protection functions of the main line semiconductor fuse 531 and the branch line semiconductor fuse 532, enables the protection function of the branch line semiconductor fuse 532 first, and then disables the protection function of the main line semiconductor fuse 531. This ensures that when vehicle C transitions to a normal state, enabling the protection function of the branch line semiconductor fuse 532 first reliably prevents a period in which both the main line semiconductor fuse 531 and the branch line semiconductor fuse 532 protection functions are disabled.

The control unit 11 of the on-board device 1 disables the protection function of the main semiconductor fuse 531 when the vehicle C is not in standby mode (in normal mode), but is not limited to this. The control unit 11 of the on-board device 1 may also change (set) the tripping characteristics of the main semiconductor fuse 531 to tripping characteristics corresponding to the normal state, i.e., the same tripping characteristics as the mechanical relay 52 and fuse 521 (fusible fuse) when the vehicle C is in normal mode. The main semiconductor fuse 531 and the mechanical relay 52 and fuse 521 (fusible fuse) are connected in parallel (forming a parallel circuit), so even if a failure occurs in one of the circuits, the other circuit can continue to provide the protection function that the vehicle C has under normal conditions.

The control unit 11 of the on-board device 1 starts tripping control for the semiconductor fuses 532 for branch lines, which have tripping characteristics set according to the normal state (S1023). The tripping characteristics of each semiconductor fuse 532 for branch lines, each of the multiple branch lines 512, are stored in the storage unit 12, for example, as tripping characteristic curves. The control unit 11 of the on-board device 1 starts tripping control for the semiconductor fuses 532 for branch lines according to the tripping characteristic curves stored in the storage unit 12.

The control unit 11 of the in-vehicle device 1 acquires the current value of the branch line 512 from a branch line current sensor located on the branch line 512, or from a current sensor built into the IPD that constitutes the branch line semiconductor fuse 532. Based on the interruption characteristic curve stored in the memory unit 12, if a current value corresponding to an overcurrent flows for a predetermined period or longer, the control unit 11 of the in-vehicle device 1 opens (turns off) the branch line semiconductor fuse 532, interrupting the current (overcurrent) flowing through the branch line 512.

After executing S105 or S1023, the control unit 11 of the in-vehicle device 1 performs loop processing to resume processing from S101. This allows the control unit 11 of the in-vehicle device 1 to continuously acquire (derive) information regarding the power consumption state of vehicle C on a periodic or steady basis, and to continuously perform the process of determining whether the current state of vehicle C is in standby mode (low current consumption mode) or normal mode (normal current mode).

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims, not in the sense described above, and all modifications within the sense and scope equivalent to the claims are intended.

Regarding the multiple claims described in the patent claims, they can be combined with each other regardless of the form of citation. Multiple dependent claims that depend on multiple claims may be described in the patent claims. Multiple dependent claims that depend on multiple dependent claims may also be described. Even if multiple dependent claims that depend on multiple dependent claims are not described, this does not limit the description of multiple dependent claims that depend on multiple dependent claims.

C Vehicle
S: In-vehicle system; 1: In-vehicle device; 11: Control unit; 12: Memory unit; M: Recording medium; P: Control program (program product)
13. Communication section 14. Input/Output I/F
140 Signal line 2 In-vehicle ECU
3. In-vehicle network 31. Communication line 5. Power supply unit 51. Power line 511. Main line 512. Branch line 513. Current detection unit (main line current sensor)
52 Mechanical relay 521 Fuse (fusible fuse)
531 Semiconductor fuse for main line 532 Semiconductor fuse for branch line 6 Vehicle load

Claims (7)

An in-vehicle device that controls the opening and closing of multiple semiconductor fuses provided in the power lines from a power supply unit mounted on a vehicle,
The system includes a control unit that performs processing related to the switching control of the semiconductor fuse,
The semiconductor fuse includes a main line semiconductor fuse placed on the main line and each of the branch line semiconductor fuses placed on each of the branch lines branching off from the main line.
The control unit,
Information regarding the power consumption status of the vehicle is obtained,
An on-board device that, in accordance with the acquired information regarding the vehicle's power consumption status, activates the protection function of the main line semiconductor fuse and deactivates the protection function of the branch line semiconductor fuse. The in-vehicle device according to claim 1, wherein the control unit, in order to activate the protection function of the main line semiconductor fuse, sets the interruption characteristics of the main line semiconductor fuse such that they are below the smoke emission characteristics corresponding to the plurality of branch lines and exceed the sum of the current values flowing through the plurality of branch lines when the vehicle is in standby mode. The power consumption state of the vehicle includes a normal state and a standby state in which power consumption is lower than that of the normal state.
The control unit,
If the acquired information regarding the vehicle's power consumption status indicates the standby state, the protection function of the main line semiconductor fuse is activated, and the protection function of the branch line semiconductor fuse is deactivated.
The in-vehicle device according to claim 2, wherein if the acquired information regarding the power consumption state of the vehicle indicates the normal state, the protective function of the main semiconductor fuse is disabled and the protective function of the branch line semiconductor fuse is enabled. A mechanical relay is connected in parallel to the aforementioned semiconductor fuse for the main line,
The in-vehicle device according to claim 2, wherein the control unit maintains the mechanical relay in the open state when the vehicle is in a standby state. The control unit,
The current value flowing through the main line in which the main line semiconductor fuse is arranged is obtained.
The in-vehicle device according to claim 2, which performs tripping control on the main semiconductor fuse, whose tripping characteristics are set according to the standby state, based on the acquired current value. A program that causes a computer to perform processing to control the opening and closing of multiple semiconductor fuses installed in the power lines from a power supply unit mounted on a vehicle,
The semiconductor fuse includes a main line semiconductor fuse placed on the main line and each of the branch line semiconductor fuses placed on each of the branch lines branching off from the main line.
Information regarding the power consumption status of the vehicle is obtained,
A program that, in accordance with the acquired information regarding the vehicle's power consumption status, enables the protection function of the main line semiconductor fuse and disables the protection function of the branch line semiconductor fuse. An information processing method that causes a computer to perform processing to control the opening and closing of multiple semiconductor fuses provided in the power lines from a power supply unit installed in a vehicle,
The semiconductor fuse includes a main line semiconductor fuse placed on the main line and each of the branch line semiconductor fuses placed on each of the branch lines branching off from the main line.
Information regarding the power consumption status of the vehicle is obtained,
An information processing method that, in accordance with the acquired information regarding the power consumption status of the vehicle, enables the protection function of the main line semiconductor fuse and disables the protection function of the branch line semiconductor fuse.