In-vehicle device, information processing method, and program

Abstract

This in-vehicle device performs cutoff control of one or more semiconductor fuses provided in a power supply line from a power supply device mounted on a vehicle. The in-vehicle device comprises: a control unit that performs processing related to the cutoff control of the semiconductor fuse; and a storage unit in which a reference value used when the control unit performs the processing is stored. The control unit acquires a current value flowing through the semiconductor fuse, determines, in a predetermined calculation cycle on the basis of the reference value and the acquired current value, whether the semiconductor fuse needs to be cut off or not, acquires state information related to a state of the vehicle in parallel with the determination processing of whether or not the semiconductor fuse needs to be cut off, and changes the calculation cycle and the reference value on the basis of the acquired state information, wherein the number of combinations of the calculation cycle and the reference value is plural.

Description

In-vehicle device, information processing method and program

[0001] This application claims priority to Japanese Patent Application No. 2023-209605 filed on December 12, 2023, and incorporates by reference all of the contents of that application.

[0002] A vehicle is equipped with a power supply control device (see, for example, Patent Document 1) that controls power supply from a battery to a load. In the power supply control device described in Patent Document 1, a downstream semiconductor fuse is provided in a current path of a 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.

[0003] JP 2013-143905 A

[0004] An on-board device according to one embodiment of the present disclosure is an on-board device that controls the interruption of one or more semiconductor fuses provided in a power supply line from a power supply device mounted on a vehicle, and includes a control unit that performs processing related to the interruption control of the semiconductor fuses, and a memory unit that stores a reference value used by the control unit when performing the processing, wherein the control unit acquires a current value flowing through the semiconductor fuse, and determines whether or not the semiconductor fuse needs to be interrupted based on the reference value and the acquired current value at a predetermined calculation period, and in parallel with the process of determining whether or not the semiconductor fuse needs to be interrupted, acquires status information related to the state of the vehicle, and changes the calculation period and the reference value based on the acquired status information, and the number of combinations of the calculation period and the reference value is multiple.

[0005] FIG. 1 is a schematic diagram illustrating the configuration of an in-vehicle system including an in-vehicle device according to a first embodiment; FIG. 2 is a block diagram illustrating the internal configuration of an in-vehicle device; FIG. 3 is an explanatory diagram illustrating a periodic constant table; FIG. 4 is an explanatory diagram illustrating a semiconductor fuse table; FIG. 5 is a flowchart illustrating the processing of a control unit of an in-vehicle device; FIG. 6 is an explanatory diagram illustrating a current threshold table according to a second embodiment; FIG. 7 is a flowchart illustrating the processing of a control unit of an in-vehicle device; FIG. 8 is an explanatory diagram illustrating a processing load threshold table according to a third embodiment; FIG. 9 is a flowchart illustrating the processing of a control unit of an in-vehicle device; FIG. 10 is an explanatory diagram illustrating a drive channel number table according to a fourth embodiment; FIG. 11 is a flowchart illustrating the processing of a control unit of an in-vehicle device; FIG. 11 is an explanatory diagram illustrating a vehicle scene table according to a fifth embodiment; and FIG. 12 is a flowchart illustrating the processing of a control unit of an in-vehicle device.

[0006] [Problem to be Solved by the Present Disclosure] However, the power supply control device described in Patent Document 1 does not take into consideration changing the calculation cycle, etc., when controlling the shutoff of the semiconductor fuse depending on the state of the vehicle, etc.

[0007] The present disclosure has been made in consideration of the above circumstances, and aims to provide an in-vehicle device etc. that can change the calculation period etc. when controlling the interruption of a semiconductor fuse depending on the state of the vehicle etc.

[0008] Effect of the Present Disclosure According to one aspect of the present disclosure, it is possible to provide an in-vehicle device or the like that changes the calculation cycle or the like when controlling the interruption of a semiconductor fuse depending on the state of the vehicle or the like.

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

[0010] (1) An on-board device according to one aspect of the present disclosure is an on-board device that controls the interruption of one or more semiconductor fuses provided in a power supply line from a power supply device mounted on a vehicle, and includes a control unit that performs processing related to the interruption control of the semiconductor fuses, and a memory unit that stores a reference value used by the control unit when performing the processing, wherein the control unit acquires a current value flowing through the semiconductor fuse, and determines whether or not the semiconductor fuse needs to be interrupted based on the reference value and the acquired current value at a predetermined calculation period, and in parallel with the process of determining whether or not the semiconductor fuse needs to be interrupted, acquires status information related to the state of the vehicle, and changes the calculation period and the reference value based on the acquired status information, and the number of combinations of the calculation period and the reference value is multiple.

[0011] In this aspect, the control unit of the in-vehicle device controls the opening and closing of a semiconductor fuse provided in a power line from a power supply device. When an overcurrent flows through the power line, the control unit controls the semiconductor fuse by turning off (opening) the semiconductor fuse to interrupt the overcurrent according to the interruption characteristics defined by the semiconductor fuse. To perform the interruption control, the control unit of the in-vehicle device detects a current (current value) flowing through the semiconductor fuse (or the branch line on which the semiconductor fuse is disposed) at a predetermined calculation period and inputs the detected current value as an input factor into a predetermined calculation formula to determine whether or not to interrupt the semiconductor fuse. In this case, the current detection period (current detection period) may be substantially equal to the calculation period (interruption calculation period) of the interruption control (interruption calculation period), or the current detection period may be shorter than the calculation period (current detection period<interruption calculation period). When 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 on / off (open / close) of the semiconductor fuse in response to a drive request for the in-vehicle load. That is, the semiconductor fuse may be opened or closed (on / off controlled) by a control unit to start or stop power supply to an on-board load connected to the semiconductor fuse, thereby controlling the drive of the on-board load (performing a drive control function). A power line extending from a power supply device may be branched into multiple lines, and a semiconductor fuse may be disposed in each of the branched power lines (branch lines), thereby forming a parallel circuit using these multiple semiconductor fuses. The control unit of the on-board device may acquire information regarding the power consumption state of the vehicle (status information) by acquiring, for example, a signal from an IG switch or a power switch that controls the start and stop of the vehicle. Alternatively, the control unit of the on-board device may acquire information regarding the operating state of the vehicle (status information) by acquiring, for example, information regarding the vehicle speed, information regarding the rotation of the engine or drive motor, etc., from an on-board ECU connected to an on-board network.Alternatively, the control unit of the in-vehicle device may detect its own CPU utilization rate or the current value flowing through a semiconductor fuse that the control unit controls to open or close, and acquire the CPU utilization rate or current value as vehicle status information. Based on the status information including such various data or detected values, the control unit of the in-vehicle device changes the calculation period when controlling the semiconductor fuse to cut off, and reference values ​​such as parameters or constants used when performing the calculation. The reference values ​​may be coefficients, constants, or correction values ​​stored in the storage unit of the in-vehicle device and included in an arithmetic formula (a function included in a program) used when performing the calculation. In other words, the reference values ​​are values ​​corresponding to items related to the calculation period, which are input factors. Thus, the arithmetic formula includes items related to the calculation period (e.g., constant A) and items unrelated to the calculation period (e.g., constant B), which are input factors. The control unit of the in-vehicle device changes the reference value, which is an item related to the calculation period (e.g., constant A), in conjunction with the change in the calculation period. The control unit of the in-vehicle device changes the calculation period and the reference value based on the acquired status information, in parallel with the process of determining whether the semiconductor fuse needs to be cut off. The number of combinations of these calculation periods and reference values ​​may be multiple, and the control unit of the in-vehicle device may identify a reference value corresponding to the calculation period from the multiple combinations of calculation periods and reference values. In this way, when changing the calculation period for the shutoff control, which has a relatively high calculation load, in accordance with the vehicle state (status information), the control unit of the in-vehicle device can reduce the number of calculations (shutoff control calculations) performed in a predetermined processing unit period by increasing (lengthening) the calculation period. This prevents an increase in the calculation load on the control unit of the in-vehicle device and increases the number of semiconductor fuses that the control unit can control to be shut off. Furthermore, when changing the calculation period, the control unit of the in-vehicle device also changes the reference values ​​(constants for items related to the calculation period, etc.) used when performing the shutoff control calculation.As a result, even if the calculation period is changed, for example, by lengthening it, an arithmetic formula is used that includes a reference value (changed reference value) that appropriately corresponds to the changed calculation period, so the accuracy of the calculation result using the arithmetic formula, i.e., the accuracy of determining whether or not a cut-off has occurred, is not affected, and deterioration of the determination accuracy can be suppressed, allowing for efficient cut-off control.

[0012] (2) In an in-vehicle device according to one aspect of the present disclosure, the memory unit stores correspondence information that associates the calculation period with the reference value, and the control unit derives a calculation period according to the vehicle status information and identifies the reference value that corresponds to the derived calculation period by referring to the correspondence information.

[0013] In this aspect, the storage unit of the in-vehicle device stores correspondence information (5 ms:A, 10 ms:A', 15 ms:A'') in table format (periodic constant table) that associates each calculation period changed by the control unit of the in-vehicle device with each reference value. When changing the calculation period and the reference value in conjunction with each other, the control unit of the in-vehicle device can efficiently identify the reference value that corresponds to the calculation period by referring to the periodic constant table that associates each calculation period with each reference value.

[0014] (3) In an in-vehicle device according to one aspect of the present disclosure, the status information includes information regarding the open / closed state of the semiconductor fuse, and the control unit makes the calculation period when the semiconductor fuse is in the open state longer than the calculation period when the semiconductor fuse is in the closed state.

[0015] In this aspect, the state information includes information regarding the open / closed state of the semiconductor fuse, i.e., information indicating whether the semiconductor fuse is in a closed state or an open state. The control unit changes the calculation period and the reference value so that the calculation period for a semiconductor fuse in an open state is longer than the calculation period for a semiconductor fuse in a closed state. This makes it possible to relatively lengthen the calculation period when the semiconductor fuse is in an open state, i.e., when the on-vehicle load connected to the semiconductor fuse is stopped, thereby reducing the number of calculations (shutdown control calculations) performed in a predetermined processing unit period and suppressing an increase in the calculation load on the control unit.

[0016] (4) In an in-vehicle device according to one aspect of the present disclosure, the state information includes the elapsed time when the semiconductor fuse transitions from a closed state to an open state, and the control unit changes the calculation period and the reference value by increasing the calculation period as the elapsed time increases.

[0017] In this aspect, the state information includes whether the semiconductor fuse, which the control unit of the in-vehicle device controls to cut off, is in a closed state (on) or an open state (off), and the elapsed time when the semiconductor fuse transitioned from the closed state (on) to the open state (off) or from the open state (off) to the closed state (on). The control unit of the in-vehicle device increases the calculation period as the elapsed time when the semiconductor fuse transitioned from the closed state (on) to the open state (off) increases, i.e., as time passes. That is, the control unit of the in-vehicle device may, for example, set the calculation period to 10 ms until 10 seconds have elapsed since the semiconductor fuse transitioned from the closed state (on) to the open state (off) (the transition time immediately after the semiconductor fuse turned off), and change the calculation period to 20 ms after 10 seconds have elapsed since the transition. In this case, the control unit of the in-vehicle device changes a reference value (e.g., constant A) used in a calculation formula or the like (A' [10 ms] → A''' [20 ms]) in accordance with the change in the calculation period. When the semiconductor fuse transitions from a closed state (on) to an open state (off), the control unit of the in-vehicle device may gradually increase the calculation period in multiple steps, such as three steps, as the elapsed time increases (10 ms: 10 seconds from the transition point, 15 ms: 10 seconds to 20 seconds after the transition point, 20 ms: 20 seconds after the transition point). The control unit of the in-vehicle device may shorten the calculation period (5 ms) when the semiconductor fuse is in the closed state (on) compared to the calculation period (10 ms, 20 ms) when the semiconductor fuse is in the open state (off). In this case, when the semiconductor fuse transitions from the open state (off) to the closed state (on), the control unit of the in-vehicle device may immediately shorten the calculation period to the calculation period (5 ms) when the semiconductor fuse is in the closed state (on). In this way, when the semiconductor fuse is in the open state (off), the control unit of the in-vehicle device increases (lengthens) the calculation cycle compared to when the semiconductor fuse is in the closed state (on), thereby reducing the number of calculations (shutoff control calculations) performed in a specified processing unit period and preventing an increase in the calculation load.In this case, the control unit of the in-vehicle device increases (lengthens) the calculation cycle in stages according to the time elapsed when the semiconductor fuse transitions from a closed state (on) to an open state (off), so that compared to simply changing the calculation cycle in the closed state (on) or open state (off), the control unit of the in-vehicle device can efficiently perform cutoff control using a calculation cycle that is changed in stages according to the elapsed state of the semiconductor fuse that has been switched from on to off. By gradually changing the reference value included in the calculation formula, etc. in conjunction with the calculation cycle that is changed in stages according to the elapsed state of the semiconductor fuse in this way, the control unit of the in-vehicle device can efficiently perform cutoff control without affecting the accuracy of the calculation result by the calculation formula, i.e., the accuracy of determining whether or not the fuse has been cut off.

[0018] (5) In an in-vehicle device according to one aspect of the present disclosure, the status information includes information about an in-vehicle load to which the semiconductor fuse is connected, and the control unit changes the calculation period and reference value to be optimal depending on the in-vehicle load.

[0019] In this aspect, an on-board load is connected in series to the semiconductor fuse on the downstream side of the power line (branch line) in the direction of current flow from the power supply device. In this case, the status information acquired by the control unit includes information about the on-board load to which the semiconductor fuse is connected. The information about the on-board load includes information about the type of the on-board load, such as whether the on-board load vibrates at a high frequency or has small current fluctuations, and information about the type of the on-board load, such as its operating mode, model, or specifications. For example, the control unit may shorten the calculation period for on-board loads with high frequency vibrations and lengthen the calculation period for on-board loads with small current fluctuations. In this way, calculation periods corresponding to the types of on-board loads may be stored in a storage unit in table format, and the control unit may derive an optimal calculation period and reference value for each type of on-board load by referring to the table. The information about the on-board load may be a load current value flowing through the on-board load. In this case, a current detection unit, such as a current sensor, is provided in the power line (branch line) in which the semiconductor fuse is disposed. The control unit of the in-vehicle device acquires the current value (load current value) detected by the current detection unit, for example, at a calculation cycle, and stores the acquired load current value in a memory unit in association with the time of acquisition. Alternatively, the semiconductor fuse may be configured, for example, as an IPD (Intelligent Power Device), and the control unit of the in-vehicle device may acquire the value of the load current (load current value) flowing through the semiconductor fuse from a current sensor (current detection unit) included in the IPD (semiconductor fuse). The control unit of the in-vehicle device decreases the calculation cycle as the load current value increases. That is, the control unit of the in-vehicle device increases the calculation cycle as the load current value decreases. In this way, the load current value and the calculation cycle are set to be inversely proportional to each other (current threshold table). By gradually decreasing the calculation cycle as the load current value increases, the number of calculations (shutdown control calculations) performed in a predetermined processing unit period can be gradually increased when the load current value is relatively high, thereby improving responsiveness when the semiconductor fuse needs to be shut down.By gradually increasing the calculation period as the load current value decreases, when the load current value is relatively low, the number of times that calculations (shutdown control calculations) are performed in a specified processing unit period can be gradually reduced, thereby efficiently suppressing an increase in the calculation load on the control unit while ensuring responsiveness in determining whether or not the semiconductor fuse has been shut down.

[0020] (6) In an in-vehicle device according to one aspect of the present disclosure, the status information includes a usage rate of the control unit, and the control unit changes the calculation period and the reference value by increasing the calculation period as the usage rate increases.

[0021] In this aspect, the control unit of the in-vehicle device steadily or periodically acquires its own utilization rate (CPU utilization rate), associates the acquired utilization rate (CPU utilization rate) with the time of acquisition, and stores the associated utilization rate (CPU utilization rate) in a storage unit. The control unit of the in-vehicle device increases the calculation cycle as the utilization rate (CPU utilization rate) increases. That is, the control unit of the in-vehicle device decreases the calculation cycle as the utilization rate (CPU utilization rate) decreases. In this way, the utilization rate (CPU utilization rate) of the control unit and the calculation cycle are set to be directly proportional to each other (processing load threshold table). By increasing the calculation cycle as the utilization rate (CPU utilization rate) increases, the number of calculations (shutdown control calculations) performed in a predetermined processing unit period can be gradually reduced, ensuring responsiveness in determining whether the semiconductor fuse has been shut down while preventing the control unit from exceeding its processing limit.

[0022] (7) In one aspect of the in-vehicle device of the present disclosure, the status information includes the number of in-vehicle loads currently being driven among the in-vehicle loads connected to each of the plurality of semiconductor fuses, and the control unit changes the calculation period and the reference value by increasing the calculation period as the number of in-vehicle loads currently being driven increases.

[0023] In this aspect, the control unit of the in-vehicle device controls the opening and closing of multiple semiconductor fuses. These multiple semiconductor fuses are arranged in parallel circuits on multiple power lines (branch lines). The control unit of the in-vehicle device controls the driving or stopping of in-vehicle loads connected to the semiconductor fuses by turning on and off (opening and closing) the semiconductor fuses based on communication data such as CAN messages transmitted from the in-vehicle ECU via the in-vehicle network or signals output from sensors, switches, etc. The control unit of the in-vehicle device stores the current open and closed states of each of the multiple semiconductor fuses in a memory unit. The control unit of the in-vehicle device increases the calculation cycle as the number of in-vehicle loads, i.e., the number of semiconductor fuses in the ON (closed) state, increases. In other words, the control unit of the in-vehicle device decreases the calculation cycle as the number of in-vehicle loads (i.e., the number of semiconductor fuses in the ON (closed) state) decreases. In this way, the number of in-vehicle loads (i.e., the number of semiconductor fuses in the ON (closed) state) and the calculation cycle are set to be directly proportional to each other. The number of driven on-board loads may be defined by the number of channels (drive channels) used for communication with semiconductor fuses connected to the on-board loads. That is, when, for example, three channels (three pins) are used for communication between the semiconductor fuses and the control unit, the control unit of the on-board device may change the calculation period according to the number of channels (number of drive channels) connected to the semiconductor fuses connected to the driven on-board loads. By increasing the calculation period as the number of driven on-board loads (number of drive channels) increases, the number of calculations (shutdown control calculations) performed in a predetermined processing unit period can be gradually reduced, thereby ensuring the responsiveness of the determination of whether the semiconductor fuses are shut down and preventing the control unit from exceeding its processing limit.

[0024] (8) In one aspect of the in-vehicle device of the present disclosure, the status information includes information indicating whether the in-vehicle device is in normal mode or low power consumption mode, and the control unit changes the calculation period and the reference value by making the calculation period of the in-vehicle device in the normal mode shorter than the calculation period of the in-vehicle device in the low power consumption mode.

[0025] In this aspect, the state information includes information indicating whether the in-vehicle device is in normal mode or low power consumption mode, i.e., information regarding its own operating mode. The control unit of the in-vehicle device may transition to normal mode (upon receiving a wake-up signal) or low power consumption mode (sleep signal) based on, for example, a sleep signal or a wake-up signal received via an in-vehicle network. Alternatively, the control unit of the in-vehicle device may enter normal mode or low power consumption mode depending on the operation of the vehicle itself (driving state, parked state), or may enter normal mode or low power consumption mode based on various vehicle scenes even when the vehicle is parked. The control unit of the in-vehicle device shortens the calculation cycle of the in-vehicle device in normal mode compared to the calculation cycle in low power consumption mode. This lengthens the calculation cycle in low power consumption mode compared to normal mode, thereby reducing the number of calculations (shutdown control calculations) performed in a predetermined processing unit period in low power consumption mode. Alternatively, the control unit of the in-vehicle device may change the calculation cycle and the reference value depending on the operating state of the vehicle, i.e., whether the vehicle is driving or parked. At this time, by acquiring a CAN message transmitted from the in-vehicle ECU via the in-vehicle network or a signal from the IG switch or the like, the in-vehicle device acquires information (state information) regarding the current state of the vehicle, i.e., whether the vehicle is moving or stopped. The control unit of the in-vehicle device makes the calculation period when the vehicle is moving shorter (shorter) than the calculation period when the vehicle is stopped. As a result, the calculation period when the vehicle is stopped becomes longer than the calculation period when the vehicle is moving, and the number of calculations (shutdown control calculations) performed in a predetermined processing unit period can be reduced while the vehicle is stopped. In this way, while the vehicle is stopped, the calculation load on the control unit of the in-vehicle device can be reduced, and power consumption by the control unit can be suppressed.

[0026] (9) In an in-vehicle device according to one aspect of the present disclosure, the reference value is a constant included in an arithmetic formula that uses a current value flowing through the semiconductor fuse to estimate the temperature of the power supply line in which the semiconductor fuse is installed.

[0027] In this aspect, a calculation formula is stored in the storage unit of the on-board device, with the value of the current flowing through the semiconductor fuse as an input factor. The calculation formula is a wire temperature calculation formula (wire temperature = F (current value, constant A [item related to the calculation cycle], constant B [item unrelated to the calculation cycle])) that calculates (estimates) the temperature of a power supply line (branch line) in which a conductor fuse is provided, based on the value of the current flowing through the power supply line (branch line). The process of calculating the wire temperature using the wire temperature calculation formula may be performed using a known processing method described, for example, in JP 2009-130944 A, JP 2015-23029 A, JP 2020-36461 A, etc. Even if the calculation formula (electric wire temperature calculation formula) used for the cutoff control in this way includes a reference value that is an item related to the calculation period, which is an input factor (such as constant A), the control unit of the in-vehicle device changes the reference value in conjunction with a change in the calculation period, and therefore calculates (estimates) the temperature of the power supply line (branch line) in which the conductor fuse is installed without being affected by the change in the calculation period or by mitigating the effect of the change, thereby ensuring the accuracy of estimating the temperature of the power supply line (branch line), which is a decision factor in performing the cutoff control.

[0028] (10) An information processing method according to one aspect of the present disclosure controls the shutoff of one or more semiconductor fuses provided in a power line from a power supply device mounted in a vehicle, and causes a computer having a memory unit that stores reference values ​​used in the processing to acquire a current value flowing through the semiconductor fuse, determine whether or not the semiconductor fuse needs to be shut off based on the reference value and the acquired current value at a predetermined calculation period, acquire status information regarding the state of the vehicle in parallel with the process of determining whether or not the semiconductor fuse needs to be shut off, and execute a process of changing the calculation period and the reference value based on the acquired status information.

[0029] In this aspect, it is possible to provide an information processing method that causes a computer to function as an in-vehicle device that changes the calculation cycle, etc., when controlling the interruption of a semiconductor fuse depending on the state of the vehicle, etc.

[0030] (11) A program according to one aspect of the present disclosure controls the shutoff of one or more semiconductor fuses provided in a power line from a power supply device mounted in a vehicle, and causes a computer having a memory unit that stores reference values ​​used in performing the processing to acquire a current value flowing through the semiconductor fuse, determine whether or not the semiconductor fuse needs to be shut off based on the reference value and the acquired current value at a predetermined calculation period, acquire status information regarding the state of the vehicle in parallel with the process of determining whether or not the semiconductor fuse needs to be shut off, and execute a process of changing the calculation period and the reference value based on the acquired status information.

[0031] In this aspect, a program can be provided that causes a computer to function as an on-board device that changes the calculation cycle, etc., when controlling the interruption of a semiconductor fuse, depending on the state of the vehicle, etc.

[0032] [Details of the embodiment of the present disclosure] The present disclosure will be specifically described with reference to the drawings showing the embodiment. An in-vehicle device 1 according to the embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0033] (Embodiment 1) Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating the configuration of an in-vehicle system S including an in-vehicle device 1 according to embodiment 1. FIG. 2 is a block diagram illustrating the internal configuration of the in-vehicle device 1. The in-vehicle system S is composed of an in-vehicle device 1 mounted on a vehicle C, an in-vehicle ECU 2, and an in-vehicle network 3 that communicatively connects these devices. The in-vehicle network 3 is composed 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 line 31 corresponds to a CAN bus.

[0034] The vehicle C is equipped with a power supply device 5 configured with a lead battery, an alternator, a secondary battery, or the like. The power supply device 5 and the in-vehicle device 1 are connected by a power line 511. The power supply device 5 and the in-vehicle device 1 are not limited to being directly connected by the power line 511, but may be indirectly connected via an electrical box (junction box) such as a relay box or a fuse box interposed between the power supply device 5 and the in-vehicle device 1.

[0035] The on-board device 1 and the multiple on-board loads 6 or the on-board ECU 2 are connected by a power supply line 511 (branch line 513), and the on-board device 1 distributes power to the multiple on-board loads 6 or the on-board ECU 2. That is, the on-board device 1 functions as a power distribution device that distributes power supplied from the power supply device 5 via the power supply line 511 to the multiple on-board loads 6 or the on-board ECU 2 that are arranged downstream in the direction of current flow.

[0036] A power supply line 511 extending from the power supply device 5 is directly or indirectly connected to each of the plurality of semiconductor fuses 50 provided in the in-vehicle device 1. That is, the power supply line 511 arranged inside the in-vehicle device 1 includes a plurality of branch lines 513 branched into a plurality of lines according to the number of semiconductor fuses 50, and a main electric wire located upstream in the direction of current flow from branch points of the plurality of branch lines 513. By arranging a semiconductor fuse 50 in each of the plurality of branched branch lines 513 in this manner, a parallel circuit is formed by the plurality of semiconductor fuses 50.

[0037] A current detection unit 512 is disposed on each branch line 513 on which each semiconductor fuse 50 is disposed. When the semiconductor fuse 50 is configured, for example, as an IPD having a built-in current sensor (current detection unit 512), the control unit 11 of the in-vehicle device 1 acquires a load current value or a voltage value converted according to the load current value from a current value output terminal (IS terminal) provided on the IPD. Alternatively, the current detection unit 512 may be a current sensor configured, for example, with a shunt resistor or the like, disposed between the semiconductor fuse 50 and the in-vehicle load 6. The current detection unit 512 periodically or steadily detects the detected current value, i.e., the load current value flowing from the semiconductor fuse 50 to the in-vehicle load 6, and outputs the detected current value (load current value) to the control unit 11 of the in-vehicle device 1.

[0038] A semiconductor fuse 50 is disposed in each of the plurality of branch lines 513, and the semiconductor fuse 50 is configured, for example, by an IPD (Intelligent Power Device). Alternatively, the semiconductor fuse 50 may be configured, for example, by a semiconductor relay such as a FET (Field Effect Transistor), a mechanical relay, or an open / close switch, and function as an open / close device. In each of the plurality of branch lines 513, an in-vehicle load 6 or an in-vehicle ECU 2 may be connected downstream of the semiconductor fuse 50 in the direction of current flow from the power supply line 511.

[0039] The on-board loads 6 are, for example, actuators such as a car air conditioner, lamps, or drive motors. The on-board ECU 2 includes a microcomputer with communication capabilities and performs predetermined calculations based on detected values ​​from sensors or output values ​​from various switches. These on-board loads 6 and the like are activated or stopped by starting or cutting off the power supply in response to the opening and closing control (on / off control) of a semiconductor fuse 50 arranged in the branch line 513. The on-board device 1 functions as a power supply control device that controls the activation and stopping of the on-board loads 6 and the like by controlling the opening and closing (on / off control) of these semiconductor fuses 50.

[0040] The in-vehicle device 1 functions as a power supply control device that controls the activation or deactivation of the in-vehicle ECU 2 and may be a device having a relay function such as a CAN gateway. Alternatively, the in-vehicle device 1 may be an integrated ECU (vehicle computer) that controls the entire vehicle C in an integrated manner and has a relay function. Alternatively, the in-vehicle device 1 may be an individual ECU connected to the integrated ECU and disposed in each area of ​​the vehicle C. Alternatively, the in-vehicle device 1 may be configured as a body ECU that controls body actuators of the vehicle C. Alternatively, the in-vehicle device 1 may be a PLB (Power LAN Box) that not only relays communications but 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 in-vehicle devices such as actuators. The in-vehicle device 1 may be connected to in-vehicle devices such as various switches, sensors, and actuators.

[0041] The in-vehicle device 1 includes a control unit 11, a storage unit 12, a communication unit 13, and an input / output I / F 14. The control unit 11 is configured with a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and performs various control processes and arithmetic processes by reading and executing a control program P (program product) and data stored in advance in the storage unit 12.

[0042] The storage unit 12 is configured with a volatile memory element such as a random access memory (RAM), a non-volatile memory element such as a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory, or a combination of these storage devices, and stores a control program P (program product) and data to be referenced during processing in advance. The control program P (program product) stored in the storage unit 12 may be a control program P (program product) read from a recording medium M readable by 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.

[0043] The communication unit 13 is an input / output interface that uses a communication protocol such as CAN, CAN-FD, or Ethernet (registered trademark), and the control unit 11 communicates with the in-vehicle ECU 2 connected to the in-vehicle network 3 via the communication unit 13. The in-vehicle device 1 may be provided with a plurality of communication units 13.

[0044] The input / output I / F 14 is, for example, a communication interface for serial communication. The input / output I / F 14 includes a plurality of terminals (output terminals), and each of the terminals is connected to a signal line 140 extending to each of the semiconductor fuses 50 and a signal line 140 extending to each of the current detection units 512. The signal line 140 is, for example, a serial cable, a wire harness, or a conductive cable (direct wire) that transmits only one signal.

[0045] 3 is an explanatory diagram illustrating an example of a periodic constant table. The storage unit 12 of the in-vehicle device 1 stores a periodic constant table, which defines the relationship between a calculation period and a reference value corresponding to the calculation period (a constant (A constant) corresponding to an item related to the calculation period in the calculation formula). The periodic constant table includes, for example, the calculation period and the reference value as management items (fields).

[0046] The calculation period management item stores the value of the calculation period (unit: ms) that is determined (derived) according to the operating state of vehicle C. The reference value management item stores a reference value (constant) that corresponds to the calculation period stored in the same record. In this way, there are multiple combinations of calculation periods and reference values. The reference value (constant) is a constant, coefficient, correction value, etc. included in the calculation formula used to determine whether or not shut-off control is required. By changing the reference value (constant) in this way in conjunction with a change in the calculation period, the accuracy of the output value of the calculation formula used to determine whether or not shut-off control is required can be ensured even if the calculation period is changed.

[0047] The reference value management item may store an arithmetic expression corresponding to each calculation cycle instead of a reference value (constant). In this case, the control unit 11 of the in-vehicle device 1 may use a different arithmetic expression depending on each calculation cycle. In this case, the reference value corresponding to each calculation cycle corresponds to the arithmetic expression corresponding to each calculation cycle.

[0048] 4 is an explanatory diagram illustrating a semiconductor fuse 50 table. The storage unit 12 of the in-vehicle device 1 stores the semiconductor fuse 50 table, which functions as a management table for saving and managing the current state of each of the semiconductor fuses 50 managed by the control unit 11 of the in-vehicle device 1, the load current value flowing through the branch line 513 to which the semiconductor fuse 50 is connected, and other information. The control unit 11 of the in-vehicle device 1 stores the load current value acquired from the current detection unit 512, the ON command or OFF command output to the semiconductor fuse 50, and the changed calculation period (current calculation period) described below in the semiconductor fuse 50 table, thereby enabling timely monitoring of matters related to the semiconductor fuse 50 at the current time. The semiconductor fuse 50 table includes management items (fields), such as an ID, an open / close state, an elapsed time, a calculation period, a load current value, a load name, and a used channel.

[0049] The ID management item stores a device number or identifier that uniquely identifies the semiconductor fuse 50. The open / close state management item stores the open / close state of the semiconductor fuse 50 stored in the same record. The elapsed time management item stores the elapsed time from the transition point (the most recent transition point) when the semiconductor fuse 50 transitioned from on to off or from off to on. In other words, the time (period) indicating how long the current open / close state has been maintained is stored. The elapsed time management item stores the time of the most recent transition point, and the control unit 11 may calculate the elapsed time by subtracting the time of the most recent transition point from the current time. The calculation cycle management item stores the current calculation cycle (unit: ms) that has been changed for the semiconductor fuse 50 stored in the same record based on the calculation cycle change process described below.

[0050] The load current value management item stores the current value flowing through the semiconductor fuse 50 stored in the same record, i.e., the load current value flowing from the semiconductor fuse 50 to the vehicle load 6. The load name management item stores the device name, etc., of the vehicle load 6 connected to the semiconductor fuse 50 stored in the same record. Furthermore, the load name management item may store information indicating the type, such as the model, of the vehicle load 6. In this case, the control unit 11 of the vehicle-mounted device 1 may derive an appropriate calculation period according to the type of vehicle load 6 based on a predetermined association between the type of vehicle load 6 and the calculation period. The used channel management item stores the number (ch number) of the channel used to control the semiconductor fuse 50 stored in the same record.

[0051] 5 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 steadily performs the following processing when the vehicle C is stopped or started. When performing the processing shown in this embodiment, the control unit 11 of the in-vehicle device 1 may execute the processing related to changing the calculation period and reference value (S101 to S106) and the processing related to cut-off control using the changed calculation period and reference value (T101 to T105) in parallel processing by generating multiple subprocesses, for example. In this case, the change processing period for executing the processing related to changing the calculation period and reference value may be shorter than the calculation period for executing the processing related to cut-off control.

[0052] The control unit 11 of the in-vehicle device 1 determines whether the semiconductor fuse 50 is on (S101). The control unit 11 of the in-vehicle device 1 checks whether an on command has been output to transition the semiconductor fuse 50, which is the object of control, to on (closed), and if the on command has been output, determines that the semiconductor fuse 50 is on (closed), and if the on command has not been output, determines that the semiconductor fuse 50 is off (open). Alternatively, the control unit 11 may check whether the state of the semiconductor fuse 50, which is the object of control, is on (closed) in a semiconductor fuse 50 table stored in the storage unit 12.

[0053] If the semiconductor fuse 50 is on (S101: YES), the control unit 11 of the in-vehicle device 1 acquires the calculation period when the semiconductor fuse 50 is on (S102). The storage unit 12 of the in-vehicle device 1 stores a calculation period corresponding to the state of the semiconductor fuse 50 and the elapsed time since the state transition. For example, when the semiconductor fuse 50 is in a closed state (on), the calculation period is stored in the storage unit 12 as 5 ms. The control unit 11 of the in-vehicle device 1 acquires the calculation period when the semiconductor fuse 50 is in a closed state (on) by referring to the storage unit 12.

[0054] If the semiconductor fuse 50 is off (S101: NO), the control unit 11 of the in-vehicle device 1 acquires the elapsed time since the semiconductor fuse 50 transitioned from on to off (S103). When controlling the opening and closing of the multiple semiconductor fuses 50 under its control, the control unit 11 stores in the memory unit 12 the time when the state transition occurred (from a closed state (on) to an open state (off) or from an open state (off) to a closed state (on)). The control unit 11 also measures and stores the elapsed time from the transition time to the present time. The control unit 11 of the in-vehicle device 1 may store information about the states of the multiple semiconductor fuses 50 in the memory unit 12, for example, by storing it in a semiconductor fuse 50 table. The control unit 11 of the in-vehicle device 1 acquires the elapsed time since the state transition occurred for the semiconductor fuse 50, which is the target of control by this process, from on to off, by referring to the semiconductor fuse 50 table.

[0055] The control unit 11 of the in-vehicle device 1 acquires a calculation period corresponding to the elapsed time when the semiconductor fuse 50 is off (S104). The storage unit 12 of the in-vehicle device 1 stores a calculation period corresponding to the elapsed time when the semiconductor fuse 50 is off. For example, a setting file or the like stores the calculation period as 10 ms until 10 seconds have elapsed since the semiconductor fuse 50 transitioned from the closed state (on) to the open state (off) (the transition point immediately after the semiconductor fuse 50 was turned off), and the calculation period as 20 ms after 10 seconds have elapsed since the transition point. Regardless of the elapsed time, the calculation period when the semiconductor fuse 50 is off may be set to be larger (longer) than the calculation period when the semiconductor fuse 50 is on. The control unit 11 of the in-vehicle device 1 acquires the calculation period corresponding to the elapsed time when the semiconductor fuse 50 is off by referring to the storage unit 12.

[0056] The control unit 11 of the in-vehicle device 1 identifies a reference value corresponding to the acquired calculation period (S105). The control unit 11 of the in-vehicle device 1 refers to the periodic constant table stored in the storage unit 12, and acquires the reference value corresponding to the acquired calculation period.

[0057] The control unit 11 of the in-vehicle device 1 changes the calculation period and the reference value for executing the cut-off control (S106). The calculation period for periodically performing the process related to the cut-off control, which will be described later, is stored in the storage unit 12 of the in-vehicle device 1. The control unit 11 of the in-vehicle device 1 changes (updates) the calculation period for periodically performing the process related to the cut-off control by, for example, overwriting the calculation period stored in the storage unit 12 with the acquired calculation period.

[0058] An arithmetic expression used in processing related to cutoff control is stored in the storage unit 12 of the in-vehicle device 1. The arithmetic expression includes a reference value corresponding to an item (A constant) related to the calculation period, which is an input factor. The control unit 11 of the in-vehicle device 1 changes the reference value for periodically performing processing related to cutoff control by, for example, overwriting the reference value (A constant) included in the arithmetic expression stored in the storage unit 12 with the reference value (A constant) specified in the periodic constant table.

[0059] When changing the calculation period and the reference value (constant A) included in the calculation formula in this manner, the control unit 11 of the in-vehicle device 1 may perform the change process individually for each of the multiple semiconductor fuses 50 that it controls. That is, the control unit 11 of the in-vehicle device 1 performs the change process individually for each of the multiple semiconductor fuses 50, and at that time, the control unit 11 may also change the calculation period and the reference value separately for each semiconductor fuse 50. By changing the calculation period and the reference value separately for each semiconductor fuse 50 in this manner, it is possible to perform appropriate cutoff control for the state of each semiconductor fuse 50. As a result, even if the number of semiconductor fuses 50 that the control unit 11 of the in-vehicle device 1 controls becomes relatively large, it is possible to ensure the reliability of the cutoff control for each semiconductor fuse 50 while suppressing an excessive processing load on the control unit 11.

[0060] The control unit 11 of the in-vehicle device 1 determines whether a calculation period has elapsed since the previous calculation process was executed (T101). Information regarding the calculation period (e.g., 5 ms) is stored in the storage unit 12, for example, by being stored in a configuration file or variables. The calculation period is periodically changed according to status information of the vehicle C, such as the status of the semiconductor fuse 50. That is, the calculation period is changed according to the time elapsed since the semiconductor fuse 50 transitioned from on to off (when the fuse 50 was switched off). As will be described in detail later, the calculation period and the reference value may be changed based not only on the status of the semiconductor fuse 50 but also on the CPU usage rate for control, the load current value flowing through the in-vehicle load 6, the number of semiconductor fuses 50 in the on state (the number of drive channels), or the operating mode (vehicle scene) of the vehicle C. That is, in this embodiment, the status information of the vehicle C includes information regarding not only the operating status of the vehicle C itself but also the status of various devices installed in the vehicle C.

[0061] The control unit 11 of the in-vehicle device 1 determines whether the elapsed time since the previous execution of the calculation process has reached the calculation cycle, which has been changed in accordance with the current state of the semiconductor fuse 50. If the calculation cycle has not elapsed (T101: NO), the control unit 11 of the in-vehicle device 1 performs loop processing to execute the process from T101 again. As a result, the control unit 11 of the in-vehicle device 1 performs standby processing in the process (sequence) related to the cutoff control from the time of the previous execution of the calculation process until the calculation cycle has elapsed, and continuously executes the process related to the cutoff control at that calculation cycle (the changed calculation cycle).

[0062] If the calculation period has elapsed (T101: YES), the control unit 11 of the in-vehicle device 1 acquires the value of the current flowing through the semiconductor fuse 50 (T102). The control unit 11 of the in-vehicle device 1 acquires the value of the current flowing through the branch line 513 on which the semiconductor fuse 50 is arranged, i.e., the value of the load current flowing through the in-vehicle load 6 connected to the semiconductor fuse 50, from the current detection unit 512. If the semiconductor fuse 50 is configured, for example, as an IPD with a built-in current sensor (current detection unit 512), the control unit 11 of the in-vehicle device 1 may acquire the load current value or a voltage value converted according to the load current value from a current value output terminal (IS terminal) provided on the IPD.

[0063] The control unit 11 of the in-vehicle device 1 executes a calculation process using an arithmetic expression including a reference value, with the acquired current value as an input factor (T103). The arithmetic expression used for performing the cutoff control is a formula that uses the current value (load current value) as an input factor and, for example, the temperature of the electric wire as an estimated output factor, and the constants included in the arithmetic expression include a constant (A constant) corresponding to an item related to the calculation cycle and a constant (B constant) corresponding to an item unrelated to the calculation cycle. The reference value, which changes in conjunction with (follows) a change in the calculation cycle, corresponds to the constant (A constant) corresponding to the item related to the calculation cycle. As described above, the reference value (the constant (A constant) corresponding to the item related to the calculation cycle) changes along with the calculation cycle in accordance with the current state information of the vehicle C.

[0064] The control unit 11 of the in-vehicle device 1 executes processing related to the cutoff control using an arithmetic expression that includes (reflects) a reference value (a constant (A constant) corresponding to an item related to the calculation cycle) that has been changed in accordance with the current state information of the vehicle C. The arithmetic expression is, for example, a wire temperature arithmetic expression (wire temperature = F (current value, A constant [item related to the calculation cycle], B constant [item unrelated to the calculation cycle])) that calculates (estimates) the temperature of the power supply line 511 (branch line 513). In this case, the output result of the arithmetic expression is the current temperature of the branch line 513 (the branch line 513 in which the semiconductor fuse 50 is located). Alternatively, the arithmetic expression may compare an input current value (load current value) with predetermined interruption characteristics that correspond to, for example, the smoke generation characteristics of the branch line 513 in which the semiconductor fuse 50 (in-vehicle load 6) is located, and output a result indicating whether the input current value (load current value) exceeds an integrated value of the overcurrent defined by the interruption characteristics.

[0065] The control unit 11 of the in-vehicle device 1 determines whether to blow the semiconductor fuse 50 based on the execution result of the arithmetic processing (T104). If the execution result of the arithmetic expression indicates, for example, that the wire temperature reaches the fuse temperature, the control unit 11 of the in-vehicle device 1 determines to blow the semiconductor fuse 50. If the execution result of the arithmetic expression indicates, for example, that the wire temperature does not reach the fuse temperature, the control unit 11 of the in-vehicle device 1 determines not to blow the semiconductor fuse 50. If it is determined not to blow the semiconductor fuse 50 (T104: NO), the control unit 11 of the in-vehicle device 1 performs loop processing to execute the processing from T101 again.

[0066] When it is determined that the semiconductor fuse 50 should be cut off (T104: YES), the control unit 11 of the in-vehicle device 1 cuts off the semiconductor fuse 50 (T105). When it is determined that the semiconductor fuse 50 should be cut off, the control unit 11 of the in-vehicle device 1 cuts off the semiconductor fuse 50, for example, by stopping the output of the gate voltage applied to the semiconductor fuse 50.

[0067] The control unit 11 of the in-vehicle device 1 may generate multiple sub-processes according to the number of semiconductor fuses 50 handled by the control unit 11, and perform a series of processes according to the flow shown in this embodiment in parallel for each of these semiconductor fuses 50.

[0068] 6 is an explanatory diagram illustrating a current threshold table according to a second embodiment. The storage unit 12 of the in-vehicle device 1 stores a current threshold table, which defines the relationship between a load current value and a calculation period corresponding to the load current value. The current threshold table includes, for example, a current value and a calculation period as management items (fields).

[0069] The current value management item stores the load current value or the range of that value. The calculation period management item stores the calculation period corresponding to the load current value (range of load current value). In the current threshold table, the calculation period is set to decrease as the load current value increases.

[0070] 7 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 steadily performs the following processing when the vehicle C is stopped or started.

[0071] The control unit 11 of the in-vehicle device 1 acquires a load current value (S201). The control unit 11 of the in-vehicle device 1 acquires the value of a current flowing through the branch line 513 on which the semiconductor fuse 50 is arranged, i.e., the value of a load current flowing through the in-vehicle load 6 connected to the semiconductor fuse 50, from the current detection unit 512. If the semiconductor fuse 50 is configured as an IPD with a built-in current sensor (current detection unit 512), for example, the control unit 11 of the in-vehicle device 1 may acquire the load current value or a voltage value converted according to the load current value from a current value output terminal (IS terminal) provided on the IPD.

[0072] The control unit 11 of the in-vehicle device 1 refers to the current threshold table and acquires the calculation period corresponding to the load current value (S202). The control unit 11 of the in-vehicle device 1 refers to the current threshold table stored in the storage unit 12 and acquires the calculation period corresponding to the acquired load current value. In the current threshold table, the calculation period is set to decrease as the load current value increases.

[0073] The control unit 11 of the in-vehicle device 1 identifies a reference value corresponding to the acquired calculation period (S203). The control unit 11 of the in-vehicle device 1 changes the calculation period and the reference value for executing the cut-off control (S204). The control unit 11 of the in-vehicle device 1 executes the processes of S203 to S204 in the same manner as S105 to S106.

[0074] The control unit 11 of the in-vehicle device 1 performs the processes T101 to T105 in the same manner as in embodiment 1, using the calculation period and reference value changed according to the current load current value, thereby performing cut-off control on the semiconductor fuse 50, which is the object of control.

[0075] 8 is an explanatory diagram illustrating a processing load threshold table according to a third embodiment. A processing load threshold table is stored in the storage unit 12 of the in-vehicle device 1, and the processing load threshold table defines the relationship between the CPU utilization rate of the control unit 11 and the operation cycle corresponding to the CPU utilization rate. The processing load threshold table includes, for example, the CPU utilization rate and the operation cycle as management items (fields).

[0076] The CPU utilization rate management item stores the CPU utilization rate of the control unit 11 or the range of the CPU utilization rate. The calculation period management item stores the calculation period corresponding to the CPU utilization rate (range of CPU utilization rate). In the processing load threshold table, the calculation period is set to increase as the CPU utilization rate increases.

[0077] 9 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 steadily performs the following processing when the vehicle C is stopped or started.

[0078] The control unit 11 of the in-vehicle device 1 acquires its own CPU utilization rate (S301). The control unit 11 of the in-vehicle device 1 acquires its own CPU utilization rate by, for example, executing a resource monitor module or the like stored in the storage unit 12.

[0079] The control unit 11 of the in-vehicle device 1 refers to the processing load threshold table and acquires the calculation period corresponding to the CPU utilization rate (S302). The control unit 11 of the in-vehicle device 1 refers to the processing load threshold table stored in the storage unit 12 and acquires the calculation period corresponding to the acquired CPU utilization rate. In the processing load threshold table, the calculation period is set to increase as the CPU utilization rate increases.

[0080] The control unit 11 of the in-vehicle device 1 identifies a reference value corresponding to the acquired calculation period (S303). The control unit 11 of the in-vehicle device 1 changes the calculation period and the reference value for executing the cut-off control (S304). The control unit 11 of the in-vehicle device 1 executes the processes of S303 to S304 in the same manner as S105 to S106 in the first embodiment.

[0081] When changing the calculation period and the reference value, the control unit 11 of the in-vehicle device 1 may uniformly apply the changed calculation period and reference value to the cutoff control of all semiconductor fuses 50 managed by the control unit 11. Alternatively, when changing the calculation period and the reference value, the control unit 11 of the in-vehicle device 1 may apply the changed calculation period and reference value in stages to the cutoff control of all semiconductor fuses 50 managed by the control unit 11, depending on the importance or priority of the in-vehicle loads 6 to which these semiconductor fuses 50 are connected. For example, the importance of each in-vehicle load 6, such as an Automotive Safety Integrity Level (ASIL), is determined depending on the implemented functions, and the changed calculation period and reference value may be applied in stages so that the calculation period connected to an in-vehicle load 6 with a high ASIL level is shorter than the calculation period connected to an in-vehicle load 6 with a low ASIL level.

[0082] The control unit 11 of the in-vehicle device 1 performs the processes T101 to T105 in the same manner as in embodiment 1, using the calculation period and reference value changed according to the current CPU usage rate of the control unit 11, thereby performing cut-off control on the semiconductor fuse 50, which is the object of control.

[0083] 10 is an explanatory diagram illustrating a drive channel number table according to a fourth embodiment. The storage unit 12 of the in-vehicle device 1 stores a drive channel number table, which defines the relationship between the number of drive channels corresponding to the number of semiconductor fuses 50 that are turned on (closed) among the semiconductor fuses 50 whose opening and closing are controlled by the control unit 11, and the calculation period corresponding to the number of drive channels (the number of semiconductor fuses 50 that are turned on). The control unit 11 of the in-vehicle device 1 and each of the semiconductor fuses 50 are connected by a plurality of channels (terminals), and the control unit 11 uses these multiple channels to communicate with each of the semiconductor fuses 50, i.e., to output control signals such as on commands or off commands, and to obtain sensor values ​​such as current values.

[0084] The management item for the number of drive channels (the number of driven vehicle loads 6) stores the number or range of numbers of drive channels corresponding to the number of semiconductor fuses 50 that are on (closed) among the semiconductor fuses 50 whose opening and closing is controlled by the control unit 11. The management item for the calculation period stores the calculation period corresponding to the number (range of numbers) of drive channels. In the drive channel number table, the calculation period is set to increase as the number of drive channels (the number of on semiconductor fuses 50) increases.

[0085] 11 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 steadily performs the following processing when the vehicle C is stopped or started.

[0086] The control unit 11 of the in-vehicle device 1 acquires the number of semiconductor fuses 50 that are in a closed state (S401). The control unit 11 of the in-vehicle device 1 acquires the number of semiconductor fuses 50 that are currently in an on state (closed state) by, for example, referring to a semiconductor fuse 50 table stored in the storage unit 12. The control unit 11 of the in-vehicle device 1 may derive the number of drive channels by referring to the semiconductor fuse 50 table based on the number of semiconductor fuses 50 that are in an on state (closed state) or the IDs of the semiconductor fuses 50.

[0087] The control unit 11 of the in-vehicle device 1 refers to the drive channel number table and acquires the calculation period corresponding to the number of drive channels (the number of ON semiconductor fuses 50) (S402). The control unit 11 of the in-vehicle device 1 refers to the drive channel number table stored in the storage unit 12 and acquires the calculation period corresponding to the acquired number of drive channels (the number of ON semiconductor fuses 50).

[0088] In the drive channel number table, the calculation period is set to increase as the number of drive channels (the number of ON semiconductor fuses 50) increases. In other words, when the number of drive channels (the number of ON semiconductor fuses 50) increases, the calculation period also increases, thereby reducing the number of calculations (number of executions) executed in a predetermined processing unit time (predetermined period), and making it possible to prevent the processing load on the control unit 11 from becoming excessively high.

[0089] The control unit 11 of the in-vehicle device 1 identifies a reference value corresponding to the acquired calculation period (S403). The control unit 11 of the in-vehicle device 1 changes the calculation period and the reference value for executing the cut-off control (S404). The control unit 11 of the in-vehicle device 1 executes the processes of S403 to S404 in the same manner as S303 to S304 in the third embodiment.

[0090] 12 is an explanatory diagram illustrating a vehicle scene table according to the fourth embodiment. The storage unit 12 of the in-vehicle device 1 stores a vehicle scene table, which defines the relationship between a vehicle operation state (vehicle scene) and a corresponding calculation period. The vehicle scene table includes, as management items (fields), for example, the vehicle operation state and the calculation period.

[0091] The management item of the vehicle operation state stores information (vehicle scene information) indicating the operation state (vehicle scene) of the vehicle C. The vehicle scene (vehicle operation state) indicated by the vehicle scene information includes, for example, a running state, a stopped state, a driving state, a stopped state, an automatic driving state, a manual driving state, and a charging state. Furthermore, the vehicle scene (vehicle operation state) may include, for example, a state indicating the operation mode of the in-vehicle device 1, such as a normal mode of the in-vehicle device 1 or a low power consumption mode in which power consumption is lower than that in the normal mode. The management item of the calculation period stores a calculation period corresponding to the vehicle operation state (vehicle scene).

[0092] In the vehicle scene table, for example, the calculation period for the traveling state may be set to be shorter (shorter) than the calculation period for the stopped state. Furthermore, in the vehicle scene table, for example, the calculation period for the in-vehicle device 1 in the normal mode may be set to be shorter (shorter) than the calculation period for the low power consumption mode. Furthermore, in the vehicle scene table, for example, the calculation period for the autonomous driving state may be set to be longer (longer) than the calculation period for the manual driving state. When the vehicle C (vehicle scene) is in the autonomous driving state, the processing load on the control unit 11 of the in-vehicle device 1 is expected to be higher than in the manual driving state. Therefore, by lengthening the calculation period, it is possible to prevent the processing load on the control unit 11 from becoming excessively high.

[0093] 13 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 steadily performs the following processing when the vehicle C is stopped or started.

[0094] The control unit 11 of the in-vehicle device 1 acquires vehicle scene information (S501). Based on communication data such as CAN messages transmitted from the in-vehicle ECU 2 via the in-vehicle network 3 or signals output from sensors, switches, etc., the control unit 11 of the in-vehicle device 1 acquires, for example, information regarding vehicle speed, information regarding the rotation of the engine or drive motor, etc., and derives (acquires) vehicle scene information indicating the operating state of the vehicle C based on this information.

[0095] The control unit 11 of the in-vehicle device 1 refers to the vehicle scene table and acquires the calculation period corresponding to the vehicle scene (S502). The control unit 11 of the in-vehicle device 1 refers to the vehicle scene table stored in the storage unit 12 and acquires the calculation period corresponding to the acquired vehicle scene information. In the vehicle scene table, for example, the calculation period for the traveling state is set to be smaller (shorter) than the calculation period for the stopped state.

[0096] The control unit 11 of the in-vehicle device 1 identifies a reference value corresponding to the acquired calculation period (S503). The control unit 11 of the in-vehicle device 1 changes the calculation period and the reference value for executing the cut-off control (S504). The control unit 11 of the in-vehicle device 1 executes the processes of S503 to S504 in the same manner as S303 to S304 in the third embodiment.

[0097] The control unit 11 of the in-vehicle device 1 performs the processes T101 to T105 in the same manner as in embodiment 1, using the calculation period and reference value changed according to the current vehicle scene information, thereby performing cut-off control on the semiconductor fuse 50, which is the object of control.

[0098] Including this embodiment, the control unit 11 of the in-vehicle device 1 is not limited to selectively performing any one of the change processes of embodiments 1 to 5 when changing the calculation period and the reference value based on the status information of the vehicle C. In other words, the control unit 11 of the in-vehicle device 1 may perform the change process by combining the change processes exemplified in embodiments 1 to 5. The control unit 11 of the in-vehicle device 1 may, for example, accept a selection of one or more change process forms in the change processes shown in embodiments 1 to 5 from an operation switch or a diagnostic device connected to the input / output I / F 14, and change the calculation period and the reference value by combining the accepted one or more change process forms.

[0099] When a combination of multiple change processing modes is performed, the control unit 11 of the in-vehicle device 1 may also accept the priority of the change processing for the selected multiple change processing modes, and if the changes to the calculation period and reference value differ among these multiple change processing modes, the change content of the change processing mode with the highest priority may be applied. By combining multiple change processing modes in this way, it is possible to derive a calculation period and reference value that are optimal for the current overall state of the vehicle C.

[0100] The embodiments disclosed herein are to be considered as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0101] Multiple claims may be combined with each other regardless of the form of reference. The claims may contain multiple dependent claims that depend on multiple claims. Multiple dependent claims may be contained that depend on multiple dependent claims. If multiple dependent claims that depend on multiple dependent claims are not contained, this does not limit the number of multiple dependent claims that depend on multiple dependent claims.

[0102] C Vehicle S In-vehicle system 1 In-vehicle device 11 Control unit 12 Storage unit M Recording medium P Control program (program product) 13 Communication unit 14 Input / output I / F 140 Signal line 2 In-vehicle ECU 3 In-vehicle network 31 Communication line 5 Power supply device 511 Power line 512 Current detection unit 513 Branch line 50 Semiconductor fuse 6 In-vehicle load

Claims

1. An on-board device that performs cut-off control of one or more semiconductor fuses provided in a power line from a power supply device mounted on a vehicle, comprising: a control unit that performs processing related to the cut-off control of the semiconductor fuses; and a memory unit that stores a reference value used by the control unit when performing the processing, wherein the control unit acquires a current value flowing through the semiconductor fuses, and determines whether or not the semiconductor fuses need to be cut off at a predetermined calculation period based on the reference value and the acquired current value, acquires status information related to the state of the vehicle in parallel with the process of determining whether or not the semiconductor fuses need to be cut off, and changes the calculation period and the reference value based on the acquired status information, and the number of combinations of the calculation period and the reference value is multiple.

2. The in-vehicle device of claim 1, wherein the memory unit stores correspondence information that associates the calculation period with the reference value, and the control unit derives a calculation period according to the vehicle status information, and identifies the reference value that corresponds to the derived calculation period by referring to the correspondence information.

3. The in-vehicle device according to claim 2, wherein the state information includes information regarding an open / closed state of the semiconductor fuse, and the control unit makes a calculation period when the semiconductor fuse is in an open state longer than a calculation period when the semiconductor fuse is in a closed state.

4. The in-vehicle device according to claim 2, wherein the state information includes an elapsed time when the semiconductor fuse transitions from a closed state to an open state, and the control unit changes the calculation period and the reference value by increasing the calculation period as the elapsed time increases.

5. The in-vehicle device according to claim 2, wherein the state information includes information regarding an in-vehicle load to which the semiconductor fuse is connected, and the control unit changes the calculation period and the reference value to be optimal depending on the in-vehicle load.

6. The in-vehicle device according to claim 2, wherein the status information includes a usage rate of the control unit, and the control unit changes the calculation period and the reference value by increasing the calculation period as the usage rate increases.

7. The in-vehicle device according to claim 2, wherein the status information includes the number of in-vehicle loads currently being driven among the in-vehicle loads connected to each of the plurality of semiconductor fuses, and the control unit changes the calculation period and the reference value by increasing the calculation period as the number of in-vehicle loads currently being driven increases.

8. The in-vehicle device according to claim 2, wherein the state information includes information indicating whether the in-vehicle device is in a normal mode or a low power consumption mode, and the control unit changes the calculation period and the reference value by making the calculation period in the normal mode shorter than the calculation period in the low power consumption mode.

9. The in-vehicle device according to any one of claims 1 to 8, wherein the reference value is a constant included in an arithmetic expression that estimates the temperature of a power supply line in which the semiconductor fuse is provided, using a current value flowing through the semiconductor fuse.

10. An information processing method for causing a computer to perform the following processes: control the shutoff of one or more semiconductor fuses provided in a power line from a power supply device mounted in a vehicle, the computer having a memory unit for storing reference values ​​used in the processing; acquire a current value flowing through the semiconductor fuse; determine whether or not the semiconductor fuse needs to be shut off at a predetermined calculation period based on the reference value and the acquired current value; acquire status information regarding the state of the vehicle in parallel with the process of determining whether or not the semiconductor fuse needs to be shut off; and change the calculation period and the reference value based on the acquired status information.

11. A program that causes a computer to perform the following processes: control the shutoff of one or more semiconductor fuses provided in a power line from a power supply device mounted in a vehicle, and has a memory unit in which reference values ​​used in performing the process are stored; acquire a current value flowing through the semiconductor fuse; determine whether or not the semiconductor fuse needs to be shut off at a predetermined calculation period based on the reference value and the acquired current value; acquire status information regarding the state of the vehicle in parallel with the process of determining whether or not the semiconductor fuse needs to be shut off; and change the calculation period and the reference value based on the acquired status information.

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