On-vehicle device, information processing method, and program

Abstract

To provide an on-vehicle device, an information processing method, and a program in which a computation cycle or the like for control to shut down a semiconductor fuse is changed.SOLUTION: An on-vehicle device performs control to shut down one or more semiconductor fuses disposed on a power source line 511 from a power source device mounted on a vehicle. A control unit acquires a value of a current flowing through a semiconductor fuse from a current detection unit 512, determines necessity to shut down the semiconductor fuse by a prescribed computation cycle on the basis of a reference value and the acquired current value, acquires state information regarding the state of the vehicle concurrently with the determination process of the necessity to shut down the semiconductor fuse, and changes the computation cycle and the reference value on the basis of the acquired state information. The number of combinations of computation cycles and reference values is a plural number.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present technology relates to an in-vehicle device, an information processing method, and a program.

Background Art

[0002] Vehicles are 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 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.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the power supply control device described in Patent Document 1 does not consider changing the calculation cycle or the like when performing cutoff control of the semiconductor fuse according to the state of the vehicle or the like.

[0005] The present disclosure has been made in view of such circumstances, and an object thereof is to provide an in-vehicle device or the like that can change the calculation cycle or the like when performing cutoff control of a semiconductor fuse according to the state of the vehicle or the like.

Means for Solving the Problems

[0006] An in-vehicle device according to an embodiment of the present disclosure is an in-vehicle device that performs cutoff control 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 cutoff control of the semiconductor fuse, and a storage unit that stores a reference value used when the control unit performs processing. The control unit acquires a current value flowing through the semiconductor fuse, determines whether the semiconductor fuse needs to be cut off at a predetermined calculation cycle based on the reference value and the acquired current value, and acquires state information related to the state of the vehicle in parallel with the determination process of whether the semiconductor fuse needs to be cut off, and changes the calculation cycle and the reference value based on the acquired state information. The number of combinations of the calculation cycle and the reference value is plural.

Advantages of the Invention

[0007] According to one aspect of the present disclosure, it is possible to provide an in-vehicle device or the like that changes a calculation cycle or the like when performing cutoff control of a semiconductor fuse according to the state of a vehicle or the like.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] [Description of Embodiments of the Present Invention] First, the embodiments of the present disclosure will be listed and described. Also, at least a part of the embodiments described below may be arbitrarily combined.

[0010] (1) An in-vehicle device according to an aspect of the present disclosure is an in-vehicle device that performs cutoff control 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 cutoff control of the semiconductor fuse, and a storage unit that stores a reference value used when the control unit performs processing. The control unit acquires a current value flowing through the semiconductor fuse, determines whether or not to cut off the semiconductor fuse at a predetermined calculation cycle based on the reference value and the acquired current value, and in parallel with the determination process of whether or not to cut off the semiconductor fuse, acquires state information regarding the state of the vehicle, changes the calculation cycle and the reference value based on the acquired state information, and the number of combinations of the calculation cycle and the reference value is plural.

[0011] In this aspect, the control unit of the in-vehicle device performs opening and closing control of a semiconductor fuse provided in the power line from the power supply device. When an overcurrent flows through the power line, according to the breaking characteristics defined by the semiconductor fuse, the semiconductor fuse is turned off (opened) to cut off the overcurrent, thereby performing breaking control on the semiconductor fuse. When executing the breaking control, the control unit of the in-vehicle device detects the current (current value) flowing through the semiconductor fuse (or the branch line where the semiconductor fuse is arranged) at a predetermined operation cycle, and inputs the detected current value as an input factor into a predetermined arithmetic formula to determine whether breaking is necessary. At this time, the detection cycle of the current (current detection cycle) may be a cycle substantially equal to the operation cycle of the breaking control (breaking operation cycle) (current detection cycle = breaking operation cycle), or the detection cycle of the current may be shorter than the operation cycle of the breaking control (current detection cycle < breaking operation cycle). When an in-vehicle load such as an actuator is connected to the semiconductor fuse, the control unit of the in-vehicle device may perform on-off control (opening and closing control) of the semiconductor fuse according to the drive request for the in-vehicle load. That is, the semiconductor fuse may perform start or stop of power supply to the in-vehicle load connected to the semiconductor fuse and perform drive control of the in-vehicle load (exhibit a drive control function) by being subjected to opening and closing control (on-off control) by the control unit. The power line extending from the power supply device may be branched into a plurality, and a parallel circuit formed by these plurality of semiconductor fuses may be formed by arranging semiconductor fuses in each of the branched power lines (branch lines). The control unit of the in-vehicle device acquires information (state information) regarding the power consumption state of the vehicle, for example, by acquiring a signal from an IG switch or a power switch that controls the start and stop of the vehicle. Or, the control unit of the in-vehicle device may acquire information regarding the operating state (state information) of the vehicle by acquiring information regarding the vehicle speed, information regarding the rotation of the engine or the drive motor, etc. from an in-vehicle ECU connected to the in-vehicle network.Alternatively, the control unit of the in-vehicle device may detect the CPU usage rate of the control unit itself or the current value flowing through the semiconductor fuse for which the control unit is responsible for opening and closing control, and acquire these CPU usage rate or current value as the state information of the vehicle. Based on the state information including such various data or detected values, the control unit of the in-vehicle device changes the calculation cycle for performing the cutoff control on the semiconductor fuse, and the reference values such as parameters or constants used when executing the calculation. The reference value may be stored in the storage unit of the in-vehicle device and may be a coefficient, a constant, or a correction value included in the arithmetic expression (function included in the program) used when performing the calculation. That is, the reference value is a value corresponding to the item related to the calculation cycle which is an input factor. In this way, the arithmetic expression includes items related to the calculation cycle (constant A, etc.) which are input factors and items not related to the calculation cycle (constant B, etc.). The control unit of the in-vehicle device changes the reference value which is an item related to the calculation cycle (constant A, etc.) in conjunction with the change of the calculation cycle. The control unit of the in-vehicle device performs the change process of the calculation cycle and the reference value based on the acquired state information in parallel with the determination process of whether or not to cut off the semiconductor fuse. The number of combinations of these calculation cycles and reference values is plural, and the control unit of the in-vehicle device may specify the reference value corresponding to the calculation cycle among the calculation cycles and reference values composed of such plural combinations. In this way, when changing the calculation cycle related to the cutoff control with relatively high calculation load according to the state (state information) of the vehicle, the control unit of the in-vehicle device can reduce the number of executions of the calculation (cutoff control calculation) in a predetermined processing unit period by increasing (lengthening) the calculation cycle. Thereby, an increase in the calculation load by the control unit of the in-vehicle device can be suppressed, and the number of semiconductor fuses for which the control unit can be responsible for the cutoff control can be increased. Further, when changing the calculation cycle, the control unit of the in-vehicle device also changes the reference value (constant of the item related to the calculation cycle, etc.) used when performing the calculation of the cutoff control.As a result, for example, even when the operation cycle is changed by lengthening it, an arithmetic expression including a reference value (changed reference value) suitable for the changed operation cycle is used. Therefore, it is possible to suppress a deterioration in the determination accuracy, that is, to suppress an influence on the accuracy of the calculation result by the arithmetic expression, that is, the determination accuracy of whether or not to cut off, and to perform the cut-off control efficiently.

[0012] (2) In the in-vehicle device according to one aspect of the present disclosure, the storage unit stores correspondence information in which the correspondence between the operation cycle and the reference value is associated. The control unit derives an operation cycle according to the state information of the vehicle, and specifies a reference value corresponding to the derived operation cycle by referring to the correspondence information.

[0013] In this aspect, in the storage unit of the in-vehicle device, correspondence information (5 ms: A, 10 ms: A', 15 ms: A'') in which each operation cycle changed by the control unit of the in-vehicle device and each reference value are associated with each other is stored in, for example, a table format (cycle constant table). When the control unit of the in-vehicle device changes the operation cycle and the reference value in conjunction with each other, it can efficiently specify the reference value corresponding to the operation cycle by referring to the cycle constant table in which each operation cycle and each reference value are associated with each other.

[0014] (3) In the in-vehicle device according to one aspect of the present disclosure, the state information includes information regarding the open / closed state of the semiconductor fuse, and the control unit makes the operation cycle when the semiconductor fuse is in the open state longer than the operation cycle 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, that is, information indicating whether the semiconductor fuse is in the closed state or the open state. The control unit changes the operation cycle and the reference value so that the operation cycle of the semiconductor fuse in the open state is longer than the operation cycle of the semiconductor fuse in the closed state. Thereby, when the semiconductor fuse is in the open state, that is, when the in-vehicle load connected to the semiconductor fuse is stopped, the operation cycle is made relatively long, the number of executions of the operation (cutoff control operation) in a predetermined processing unit period is reduced, and an increase in the calculation load of the control unit can be suppressed.

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

[0017] In this aspect, the state information includes the state of whether the semiconductor fuse for which the control unit of the in-vehicle device is responsible for cut-off control is in a closed state (on) or an open state (off), and the elapsed time when the semiconductor fuse makes a state transition from the closed state (on) to the open state (off), or from the open state (off) to the closed state (on). As the elapsed time increases when the semiconductor fuse makes a state transition from the closed state (on) to the open state (off), that is, as time elapses, the control unit of the in-vehicle device increases the operation cycle. That is, for example, the control unit of the in-vehicle device may set the operation cycle to 10 ms until 10 seconds have elapsed from the time point when the semiconductor fuse makes a state transition from the closed state (on) to the open state (off) (the transition time point which is immediately after turning off), and after exceeding 10 seconds from the transition time point, change the operation cycle to 20 ms. At that time, the control unit of the in-vehicle device changes the reference value (constant A, etc.) used in the arithmetic formula, etc. in accordance with the change in the operation cycle (A'[10 ms] → A'''[20 ms]). The control unit of the in-vehicle device may increase the operation cycle stepwise in multiple steps such as three steps in response to the increase in the elapsed time when the semiconductor fuse makes a state transition from the closed state (on) to the open state (off) (10 ms: from the transition time point to 10 seconds, 15 ms: from 10 seconds after the transition time point to 20 seconds, 20 ms: after 20 seconds have elapsed from the transition time point). The control unit of the in-vehicle device may make the operation cycle when the semiconductor fuse is in the closed state (on) (5 ms) shorter than the operation cycle when it is in the open state (off) (10 ms, 20 ms). At this time, when the semiconductor fuse makes a state transition from the open state (off) to the closed state (on), the control unit of the in-vehicle device may immediately reduce (shorten) the operation cycle and change it to the operation cycle (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 the operation cycle (lengthens it) compared to when it is in the closed state (on), thereby reducing the number of executions of the operation (cut-off control operation) in a predetermined processing unit period and suppressing an increase in the calculation load.At this time, the control unit of the in-vehicle device increases (lengthens) the calculation cycle step by step according to the elapsed time when the semiconductor fuse changes its state from the closed state (on) to the open state (off). Therefore, compared with the case of simply changing the calculation cycle in the closed state (on) or the open state (off), the cutoff control can be efficiently performed using the calculation cycle that is changed step by step according to the elapsed state of the semiconductor fuse switched from on to off. The control unit of the in-vehicle device changes the reference value included in the arithmetic expression or the like step by step in conjunction with the calculation cycle that is changed step by step according to the elapsed state of the semiconductor fuse in this way, so that the accuracy of the calculation result by the arithmetic expression, that is, the determination accuracy of whether or not to cut off, can be efficiently performed without being affected.

[0018] (5) The in-vehicle device according to one aspect of the present disclosure, wherein the state information includes information on an in-vehicle load to which the semiconductor fuse is connected, and the control unit changes to an optimal calculation cycle and reference value according to the in-vehicle load

[0019] In this aspect, in the power line (branch line) where the semiconductor fuse is arranged, on the downstream side in the direction of the current flow from the power supply device, the in-vehicle load is connected in series to the semiconductor fuse. At this time, the state information acquired by the control unit includes information regarding the in-vehicle load to which the semiconductor fuse is connected. Information regarding the in-vehicle load includes, for example, information regarding the type such as the operation mode, model, or specification of the in-vehicle load, such as whether the in-vehicle load vibrates at a high frequency or the in-vehicle load with little current fluctuation. The control unit may, for example, shorten the calculation cycle relatively when the in-vehicle load vibrates at a high frequency, and may lengthen the calculation cycle relatively when the in-vehicle load has little current fluctuation. In this way, the calculation cycle corresponding to the type of in-vehicle load is stored in the storage unit in a table format, and by referring to this, the optimal calculation cycle and reference value may be derived according to the type of in-vehicle load. The information regarding the in-vehicle load may be the load current value flowing through the in-vehicle load. At this time, a current detection unit configured by a current sensor or the like is arranged in the power line (branch line) where the semiconductor fuse is arranged. 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 associates the acquired load current value with the acquisition time point and stores it in the storage unit. Or, the semiconductor fuse is configured by, for example, 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 the 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 (current threshold table) to be in an inverse proportional relationship. By gradually decreasing the calculation cycle as the load current value increases, when the load current value is relatively high, the number of executions of the calculation (cut-off control calculation) in a predetermined processing unit period can be gradually increased, and the responsiveness when it is necessary to cut off the semiconductor fuse can be improved.As the load current value decreases, by gradually increasing the operation cycle, when the load current value is relatively low, the number of executions of the operation (interruption control operation) in a predetermined processing unit period can be gradually reduced, ensuring the responsiveness of the determination of whether to interrupt the semiconductor fuse while efficiently suppressing an increase in the operation load of the control unit.

[0020] (6) The in-vehicle device according to one aspect of the present disclosure, wherein the state information includes the usage rate of the control unit, and the control unit changes the operation cycle and the reference value by increasing the operation cycle as the usage rate increases.

[0021] In this aspect, the control unit of the in-vehicle device regularly or periodically acquires the usage rate (CPU usage rate) of the control unit itself, associates the acquired usage rate (CPU usage rate) with the acquisition time point, and stores it in the storage unit. The control unit of the in-vehicle device increases the operation cycle as the usage rate (CPU usage rate) increases. That is, the control unit of the in-vehicle device decreases the operation cycle as the usage rate (CPU usage rate) decreases. In this way, the usage rate (CPU usage rate) of the control unit and the operation cycle are set (processing load threshold table) to be in a directly proportional relationship. By increasing the operation cycle as the usage rate (CPU usage rate) increases, the number of executions of the operation (interruption control operation) in a predetermined processing unit period can be gradually reduced, ensuring the responsiveness of the determination of whether to interrupt the semiconductor fuse while preventing the control unit from deviating from the processing limit.

[0022] (7) The in-vehicle device according to one aspect of the present disclosure, wherein the state information includes the number of in-vehicle loads being driven in each of the in-vehicle loads connected to each of the plurality of semiconductor fuses, and the control unit changes the operation cycle and the reference value by increasing the operation cycle as the number of in-vehicle loads being driven increases.

[0023] In this aspect, there are a plurality of semiconductor fuses for which the control unit of the in-vehicle device is responsible for cutoff control and opening / closing control. These plurality of semiconductor fuses are arranged on respective plurality of power lines (branch lines) to form a parallel circuit. The control unit of the in-vehicle device turns on and off (opens and closes) these 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., thereby controlling the driving or stopping of the in-vehicle loads connected to the semiconductor fuses. The control unit of the in-vehicle device stores the opening / closing states of each of the plurality of semiconductor fuses at the current time in the storage unit. The control unit of the in-vehicle device increases the calculation cycle as the number of in-vehicle loads during driving, that is, the number of semiconductor fuses in the on (closed) state, increases. That is, the control unit of the in-vehicle device decreases the calculation cycle as the number of in-vehicle loads during driving (the number of semiconductor fuses in the on (closed) state) decreases. In this way, the number of in-vehicle loads during driving (the number of semiconductor fuses in the on (closed) state) and the calculation cycle are set to be in a directly proportional relationship. The number of in-vehicle loads during driving may be defined by the number of channels (driving channels) used for communication with the semiconductor fuses connected to the in-vehicle loads. That is, in the communication between the semiconductor fuse and the control unit, for example, when 3 channels (3 pins) are used, the calculation cycle may be changed according to the number of channels (driving ch number) connected to the semiconductor fuse connected to the in-vehicle load being driven. By increasing the calculation cycle as the number of in-vehicle loads during driving (driving ch number) increases, the number of executions of the calculation (cutoff control calculation) in a predetermined processing unit period can be gradually reduced, while ensuring the responsiveness of the determination of whether to cut off the semiconductor fuse and preventing the control unit from deviating from the processing limit.

[0024] (8) The in-vehicle device according to one aspect of the present disclosure, wherein the state information includes information indicating whether the in-vehicle device is in the normal mode or the low power consumption mode, and the control unit changes the operation cycle and the reference value by making the operation cycle of the in-vehicle device in the normal mode smaller than the operation cycle in the low power consumption mode.

[0025] In this aspect, the status information includes information indicating whether the in-vehicle device, which is the own device, is in the normal mode or the low power consumption mode, that is, information regarding its own operation mode. The control unit of the in-vehicle device may transition to the normal mode (when a wake-up signal is received) or the low power consumption mode (sleep signal), for example, based on a sleep signal or a wake-up signal received via the in-vehicle network. Alternatively, the control unit of the in-vehicle device may enter the normal mode or the low power consumption mode according to the operation of the vehicle itself (driving state, stopped state). Furthermore, even when the vehicle is in the stopped state, it may enter the normal mode or the low power consumption mode based on various vehicle scenes. The control unit of the in-vehicle device makes the operation cycle of the in-vehicle device itself in the normal mode smaller than the operation cycle in the low power consumption mode. As a result, the operation cycle in the low power consumption mode becomes longer than the operation cycle in the normal mode, and in the low power consumption mode, the number of executions of the operation (interruption control operation) in a predetermined processing unit period can be reduced. Alternatively, the control unit of the in-vehicle device may change the operation cycle and the reference value according to the driving state or the stopped state, which is the operation state of the vehicle. At this time, information (status information) regarding the current state of the vehicle, that is, whether the vehicle is driving or stopped, is obtained by acquiring a CAN message transmitted from the in-vehicle ECU via the in-vehicle network or a signal from an IG switch or the like. The control unit of the in-vehicle device makes the operation cycle when the vehicle is in the driving state smaller (shorter) than the operation cycle when the vehicle is in the stopped state. As a result, the operation cycle when the vehicle is in the stopped state becomes longer than the operation cycle when the vehicle is in the driving state, and during the stop of the vehicle, the number of executions of the operation (interruption control operation) in a predetermined processing unit period can be reduced. In this way, during the stop of the vehicle, the operation load by the control unit of the in-vehicle device can be reduced, and the power consumption by the control unit can be suppressed.

[0026] (9) In the in-vehicle device according to one aspect of the present disclosure, the reference value is a constant included in an arithmetic expression for estimating the temperature of the power supply line on which the semiconductor fuse is provided, using the current value flowing through the semiconductor fuse.

[0027] In this aspect, an arithmetic expression using the value of the current flowing through the semiconductor fuse as an input factor is stored in the storage unit of the in-vehicle device. The arithmetic expression is a wire temperature arithmetic expression (wire temperature = F(current value, constant A [item related to the calculation period], constant B [item not related to the calculation period])) for calculating (estimating) the temperature of the power supply line (branch line) based on the value of the current flowing through the power supply line (branch line) where the semiconductor fuse is provided. The process of calculating the wire temperature using the wire temperature arithmetic expression may be performed using a known processing method described in, for example, Japanese Patent Application Laid-Open No. 2009-130944, Japanese Patent Application Laid-Open No. 2015-23029, Japanese Patent Application Laid-Open No. 2020-36461, etc. Even when the arithmetic expression (wire temperature arithmetic expression) used for the cutoff control includes a reference value that is an item related to the calculation period (constant A, etc.) which is an input factor, the control unit of the in-vehicle device changes the reference value in conjunction with the change in the calculation period, so as to calculate (estimate) the temperature of the power supply line (branch line) where the semiconductor fuse is provided without being affected by the change in the calculation period or by mitigating the influence, thereby ensuring the estimation accuracy of the temperature of the power supply line (branch line) which is a judgment factor in performing the cutoff control.

[0028] (10) An information processing method according to an aspect of the present disclosure performs cutoff control of one or more semiconductor fuses provided on a power supply line from a power supply device mounted on a vehicle, and causes a computer including a storage unit that stores a reference value used when performing processing to acquire a value of the current flowing through the semiconductor fuse, determine whether or not to cut off the semiconductor fuse at a predetermined calculation period based on the reference value and the acquired current value, acquire state information regarding the state of the vehicle in parallel with the determination process of whether or not to cut off the semiconductor fuse, and execute a process of changing the calculation period and the reference value based on the acquired state 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 a calculation period or the like when performing cutoff control of a semiconductor fuse according to the state of the vehicle or the like.

[0030] (11) A program according to one aspect of the present disclosure includes a computer having a storage unit that stores a reference value used when performing processing for controlling the interruption of one or more semiconductor fuses provided in a power line from a power supply device mounted on a vehicle. The computer acquires a current value flowing through the semiconductor fuse, determines whether the semiconductor fuse needs to be interrupted at a predetermined calculation cycle based on the reference value and the acquired current value, and acquires state information regarding the state of the vehicle in parallel with the determination process of whether the semiconductor fuse needs to be interrupted, and executes a process of changing the calculation cycle and the reference value based on the acquired state information.

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

[0032] [Details of Embodiments of the Present Disclosure] The present disclosure will be specifically described based on the drawings showing its embodiments. The 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, and is intended to be indicated by the claims and to include all modifications within the meaning and scope equivalent to the claims.

[0033] (Embodiment 1) Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating the configuration of an in-vehicle system S including the in-vehicle device 1 and the like 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 includes an in-vehicle device 1 mounted on a vehicle C, an in-vehicle ECU 2, and an in-vehicle network 3 that communicably connects these. 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 composed of 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, and an electrical box (junction box) such as a relay box or a fuse box may be interposed between the power supply device 5 and the in-vehicle device 1 and they may be indirectly connected.

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

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

[0037] A current detection unit 512 is arranged on each of the branch lines 513 where each of the semiconductor fuses 50 is arranged. When the semiconductor fuse 50 is constituted by, for example, an IPD (Intelligent Power Device) incorporating a 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 constituted by, for example, a shunt resistor or the like, and may be arranged between the semiconductor fuse 50 and the in-vehicle load 6. The current detection unit 512 periodically or constantly detects the detected current value, that is, 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 arranged on each of the plurality of branch lines 513, and the semiconductor fuse 50 is constituted by, for example, an IPD (Intelligent Power Device). Alternatively, the semiconductor fuse 50 may be constituted by, for example, a semiconductor relay such as an FET (Field Effect Transistor), a mechanical relay, or an open / close switch, and may function as an opening / closing device. In each of the plurality of branch lines 513, an in-vehicle load 6 or an in-vehicle ECU 2 may be connected on the downstream side of the semiconductor fuse 50 in the current flow direction from the power supply line 511.

[0039] The in-vehicle load 6 is, for example, an actuator such as a car air conditioner, a lamp, or a drive motor. The in-vehicle ECU 2 includes a microcomputer having a communication function or the like, and performs predetermined arithmetic processing based on a detection value from a sensor or an output value from various switches. The in-vehicle load 6 and the like are powered on or off according to the opening / closing control (on / off control) of the semiconductor fuse 50 arranged on the branch line 513, and are thereby started or stopped. The in-vehicle device 1 functions as a power control device that controls the start or stop of the in-vehicle load 6 and the like by performing the opening / closing control (on / off control) of these semiconductor fuses 50.

[0040] The in-vehicle device 1 functions as a power control device that controls the startup or shutdown of the in-vehicle ECU 2, and may be a device having a relay function such as a CAN gateway, for example. Alternatively, the in-vehicle device 1 may be an integrated ECU (vehicle computer) that integrally controls the entire vehicle C and has a relay function. Alternatively, the in-vehicle device 1 may be an individual ECU that is connected under the integrated ECU and is arranged in each area of the vehicle C. Alternatively, the in-vehicle device 1 may be configured as a body ECU or the like that controls the body system actuator of the vehicle C. Alternatively, the in-vehicle device 1 may also function as a PLB (Power Lan Box) that, in addition to relaying communication, distributes and relays the power output from a power supply device 5 such as a secondary battery and supplies power to in-vehicle devices such as actuators. Various in-vehicle devices such as switches, sensors, or actuators may be connected to the in-vehicle device 1.

[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 constituted by a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), etc., and reads and executes a control program P (program product) and data stored in advance in the storage unit 12 to perform various control processes, arithmetic processes, etc.

[0042] The storage unit 12 is composed of a volatile memory element such as a RAM (Random Access Memory), or a non-volatile memory element such as a ROM (Read Only Memory), an EEPROM (Electrically Erasable Programmable ROM), or a flash memory, or a combination of these storage devices, and stores in advance a control program P (program product) and data referred to during processing. The control program P (program product) stored in the storage unit 12 may store the control program P (program product) read from a recording medium M readable by the in-vehicle device 1. Further, 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 using 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. In the in-vehicle device 1, a plurality of communication units 13 may be provided.

[0044] The input / output I / F 14 is a communication interface for serial communication, for example. The input / output I / F 14 includes a plurality of terminals (output terminals), and each terminal 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 composed of, for example, a serial cable, a wire harness, or a conductive cable (single wire) that transmits only one signal.

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

[0046] In the management item of the calculation cycle, a value of the calculation cycle (unit: ms) determined (derived) according to the operating state of the vehicle C is stored. In the management item of the reference value, a reference value (constant) corresponding to the calculation cycle stored in the same record is stored. Thus, the number of combinations of the calculation cycle and the reference value is plural. The reference value (constant) is a constant, coefficient, correction value, etc. included in the calculation formula used for determining the necessity of cutoff control. By changing the reference value (constant) in conjunction with the change of the calculation cycle in this way, even when the calculation cycle is changed, the accuracy of the output value of the calculation formula used for determining the necessity of cutoff control can be ensured.

[0047] In the management item of the reference value, instead of the reference value (constant), the calculation formula itself corresponding to each calculation cycle may be stored. In this case, the control unit 11 of the in-vehicle device 1 may use different calculation formulas according to each calculation cycle. At this time, the reference value corresponding to each calculation cycle corresponds to the calculation formula corresponding to each calculation cycle.

[0048] FIG. 4 is an explanatory diagram illustrating a semiconductor fuse 50 table. In the storage unit 12 of the in-vehicle device 1, a semiconductor fuse 50 table is stored. The semiconductor fuse 50 table functions as a management table for storing and managing the current state of each of a plurality of semiconductor fuses 50 handled by the control unit 11 of the in-vehicle device 1, and the load current value flowing through the branch line 513 to which the semiconductor fuse 50 is connected, etc. 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 cycle (current calculation cycle) described later in the semiconductor fuse 50 table, whereby the matters regarding the semiconductor fuse 50 at the current time can be grasped in a timely manner. The semiconductor fuse 50 table includes, as management items (fields), for example, ID, open / close state, elapsed time, calculation cycle, load current value, load name, and used channel.

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

[0050] The management items of the load current value include the current value flowing through the semiconductor fuse 50 stored in the same record, that is, the load current value flowing from the semiconductor fuse 50 to the in-vehicle load 6. The management items of the load name include the device name of the in-vehicle load 6 connected to the semiconductor fuse 50 stored in the same record. Further, the management items of the load name may include information indicating types such as the type of the in-vehicle load 6. At this time, the control unit 11 of the in-vehicle device 1 may derive an appropriate operation cycle according to the type of the in-vehicle load 6 based on the association between the predetermined types of the in-vehicle load 6 and the operation cycle. The management items of the used channel include the channel number (ch number) of the channel used for controlling the semiconductor fuse 50 stored in the same record.

[0051] FIG. 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 constantly performs the following processing when the vehicle C is stopped or started. In performing the processing shown in this embodiment, the control unit 11 of the in-vehicle device 1 may execute the processing related to the change of the operation cycle and the reference value (from S101 to S106) and the processing related to the cutoff control using the changed operation cycle and reference value (from T101 to T105) by parallel processing, for example, by generating a plurality of sub-processes. At this time, the change processing cycle for executing the processing related to the change of the operation cycle and the reference value may be a shorter cycle than the operation cycle for executing the processing related to the cutoff 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 for transitioning the semiconductor fuse 50 to be controlled to on (closed) is output. When the on command is output, the control unit 11 determines that the semiconductor fuse 50 is on (closed), and when the on command is not output, the control unit 11 determines that the semiconductor fuse 50 is off (open). Alternatively, in the semiconductor fuse 50 table stored in the storage unit 12, it may be possible to check whether the state of the semiconductor fuse 50 to be controlled is in the on state (closed state).

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

[0054] When the semiconductor fuse 50 is off (S101: NO), the control unit 11 of the in-vehicle device 1 acquires the elapsed time since the time when the semiconductor fuse 50 has changed its state from on to off (S103). When performing the opening and closing control of the plurality of semiconductor fuses 50 that it is responsible for, the control unit 11 of the in-vehicle device 1 stores in the storage unit 12 the time point (transition time point when the state transition is made) when switching from the closed state (on) to the open state (off), or from the open state (off) to the closed state (on), and further measures and stores the elapsed time from the transition time point to the current time point. The control unit 11 of the in-vehicle device 1 may store in the storage unit 12 the information regarding the state of each of these plurality of semiconductor fuses 50, 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 time when the semiconductor fuse 50, which is the control target by this process, has changed its state from on to off by referring to the semiconductor fuse 50 table.

[0055] The control unit 11 of the in-vehicle device 1 acquires an operation cycle corresponding to the elapsed time when the semiconductor fuse 50 is off (S104). In the storage unit 12 of the in-vehicle device 1, an operation cycle corresponding to the elapsed time when the semiconductor fuse 50 is off is stored. For example, until 10 seconds elapse from the time point (the transition time point which is immediately after being off) when the semiconductor fuse 50 makes a state transition from the closed state (on) to the open state (off), the operation cycle is set to 10 ms, and after exceeding 10 seconds from the transition time point, the operation cycle is set to 20 ms, which is stored as a setting file or the like. The operation cycle when the semiconductor fuse 50 is off may be set to be larger (longer) than the operation cycle when it is on, regardless of the elapsed time. The control unit 11 of the in-vehicle device 1 acquires an operation cycle 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 specifies a reference value corresponding to the acquired operation cycle (S105). The control unit 11 of the in-vehicle device 1 refers to the cycle constant table stored in the storage unit 12 and acquires a reference value corresponding to the acquired operation cycle.

[0057] The control unit 11 of the in-vehicle device 1 changes the operation cycle and the reference value for executing the cutoff control (S106). In the storage unit 12 of the in-vehicle device 1, an operation cycle for periodically performing the process related to the cutoff control described later is stored. The control unit 11 of the in-vehicle device 1 changes (updates) the operation cycle for periodically performing the process related to the cutoff control by overwriting the operation cycle stored in the storage unit 12 with the acquired operation cycle.

[0058] In the storage unit 12 of the in-vehicle device 1, an arithmetic expression used in the process related to the cutoff control is stored. The arithmetic expression includes a reference value corresponding to an item (A constant) related to the operation cycle which is an input factor. The control unit 11 of the in-vehicle device 1 changes the reference value for periodically performing the process related to the cutoff control by 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 cycle constant table.

[0059] When changing the operation cycle and the reference value (A constant) included in the arithmetic expression in this way, the control unit 11 of the in-vehicle device 1 may individually change the change process for each of the plurality of semiconductor fuses 50 for which it is responsible for control. That is, the control unit 11 of the in-vehicle device 1 individually performs the change process for each of the plurality of semiconductor fuses 50, and at that time, the operation cycle and the reference value may also be individually changed for each of the individual semiconductor fuses 50. By separately changing the operation cycle and the reference value for each of the individual semiconductor fuses 50 in this way, it is possible to perform suitable cutoff control for the state of each semiconductor fuse 50. Thereby, even when the number of semiconductor fuses 50 for which the control unit 11 of the in-vehicle device 1 is responsible is relatively large, while suppressing the processing load by the control unit 11 from becoming excessive, the reliability of the cutoff control for each semiconductor fuse 50 can be ensured.

[0060] The control unit 11 of the in-vehicle device 1 determines whether or not an operation cycle has elapsed since the execution time of the previous arithmetic process (T101). Information regarding the operation cycle (for example, 5 ms, etc.) is stored in the storage unit 12 by being stored in, for example, a setting file or a variable. The operation cycle is periodically changed according to the state information of the vehicle C, such as the state of the semiconductor fuse 50, that is, whether the state of the semiconductor fuse 50 is on or off, or when it is off, it is changed following the elapsed time from the time point of state transition from on to off (the time point of switching to off). Although details will be described later, the operation cycle and the reference value may be changed based not only on the state of the semiconductor fuse 50 but also on the CPU usage rate of the control, the load current value flowing through the in-vehicle load 6, the number of semiconductor fuses 50 in the on state (number of drive channels), or the operation mode (vehicle scene) of the vehicle C. That is, in the present embodiment, the state information of the vehicle C includes not only the operation state of the vehicle C itself but also information regarding the states of various devices mounted on the vehicle C.

[0061] The control unit 11 of the in-vehicle device 1 determines whether the elapsed time from the execution time of the previous arithmetic process has reached the arithmetic cycle for the arithmetic cycle changed according to the state of the semiconductor fuse 50 at the current time. If the arithmetic cycle has not elapsed (T101: NO), the control unit 11 of the in-vehicle device 1 performs a loop process 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 until the arithmetic cycle elapses from the execution time of the previous arithmetic process, and continuously executes the process related to the cutoff control at the arithmetic cycle (the changed arithmetic cycle).

[0062] If the arithmetic cycle has elapsed (T101: YES), the control unit 11 of the in-vehicle device 1 acquires the current value flowing through the semiconductor fuse 50 (T102). The control unit 11 of the in-vehicle device 1 acquires the current value flowing through the branch line 513 where the semiconductor fuse 50 is disposed, that is, the load current value flowing through the in-vehicle load 6 connected to the semiconductor fuse 50, from the current detection unit 512. When the semiconductor fuse 50 is configured by an IPD incorporating, for example, a current sensor (current detection unit 512), the control unit 11 of the in-vehicle device 1 may acquire the load current value or the voltage value converted according to the load current value from the current value output terminal (IS terminal) provided in the IPD.

[0063] The control unit 11 of the in-vehicle device 1 executes an arithmetic 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 has the current value (load current value) as an input factor and is, for example, an arithmetic expression for estimating the temperature of the electric wire (output factor). The constants included in the arithmetic expression include a constant (A constant) corresponding to an item related to the arithmetic cycle and a constant (B constant) corresponding to an item not related to the arithmetic cycle. The reference value changed in conjunction with (following) the change of the arithmetic cycle corresponds to the constant (A constant) corresponding to the item related to the arithmetic cycle. The reference value (constant (A constant) corresponding to the item related to the arithmetic cycle) has been changed together with the arithmetic cycle according to the state information of the vehicle C at the current time as described above.

[0064] The control unit 11 of the in-vehicle device 1 executes the process related to the cutoff control by using an arithmetic expression that includes (reflects) a reference value (constant (A constant) corresponding to the item related to the operation cycle) changed according to the state information of the vehicle C at the current time. The arithmetic expression is, for example, a wire temperature arithmetic expression (wire temperature = F(current value, A constant [item related to the operation cycle], B constant [item not related to the operation cycle])) for calculating (estimating) the temperature of the power line 511 (branch line 513). In this case, the output result of the arithmetic expression is the temperature of the branch line 513 (branch line 513 where the semiconductor fuse 50 is arranged) at the current time. Or, the arithmetic expression may compare the input current value (load current value) with a predefined cutoff characteristic according to the smoke generation characteristic etc. of the branch line 513 where the semiconductor fuse 50 (in-vehicle load 6) is arranged, and output whether it exceeds the integrated value of the overcurrent defined by the cutoff characteristic.

[0065] Based on the execution result of the arithmetic processing, the control unit 11 of the in-vehicle device 1 determines whether to cut off the semiconductor fuse 50 (T104). When 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 cut off the semiconductor fuse 50. When 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 cut off the semiconductor fuse 50. When it is determined not to cut off the semiconductor fuse 50 (T104: NO), the control unit 11 of the in-vehicle device 1 performs a loop process to execute the process from T101 again.

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

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

[0068] (Embodiment 2) FIG. 6 is an explanatory diagram illustrating a current threshold table according to Embodiment 2. A current threshold table is stored in the storage unit 12 of the in-vehicle device 1, and the current threshold table defines the relationship between the load current value and the operation period corresponding to the load current value. The current threshold table includes, as management items (fields), for example, a current value and an operation period.

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

[0070] FIG. 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 constantly performs the following processing when the vehicle C is stopped or started.

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

[0072] The control unit 11 of the in-vehicle device 1 refers to the current threshold table and acquires the operation cycle 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 operation cycle corresponding to the acquired load current value. In the current threshold table, the operation cycle is set to decrease as the load current value increases.

[0073] The control unit 11 of the in-vehicle device 1 specifies a reference value corresponding to the acquired operation cycle (S203). The control unit 11 of the in-vehicle device 1 changes the operation cycle and the reference value in performing the cutoff control (S204). The control unit 11 of the in-vehicle device 1 executes the processes from S203 to S204 in the same manner as from S105 to S106.

[0074] The control unit 11 of the in-vehicle device 1 performs cutoff control on the semiconductor fuse 50 to be controlled by executing the processes from T101 to T105 in the same manner as in the first embodiment, using the operation cycle and the reference value changed according to the current load current value at the current time.

[0075] (Embodiment 3) FIG. 8 is an explanatory diagram illustrating a processing load threshold table according to Embodiment 3. The storage unit 12 of the in-vehicle device 1 stores a processing load threshold table, and the processing load threshold table defines the relationship between the CPU usage rate of the control unit 11 and the operation cycle corresponding to the CPU usage rate. The processing load threshold table includes, as management items (fields), for example, the CPU usage rate and the operation cycle.

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

[0077] FIG. 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 constantly performs the following processing when the vehicle C is stopped or starting.

[0078] The control unit 11 of the in-vehicle device 1 acquires the CPU usage rate of itself, i.e., the control unit 11 (S301). The control unit 11 of the in-vehicle device 1 acquires the CPU usage rate, which is its own usage rate, by executing, for example, a resource monitor module 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 cycle corresponding to the CPU usage 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 cycle corresponding to the acquired CPU usage rate. In the processing load threshold table, the calculation cycle is set to increase as the CPU usage rate increases.

[0080] The control unit 11 of the in-vehicle device 1 specifies the reference value corresponding to the acquired calculation cycle (S303). The control unit 11 of the in-vehicle device 1 changes the calculation cycle and the reference value for executing the cutoff control (S304). The control unit 11 of the in-vehicle device 1 executes the processing from S303 to S304 in the same manner as from S105 to S106 in Embodiment 1.

[0081] When changing the calculation cycle and reference value, the control unit 11 of the in-vehicle device 1 may uniformly apply the changed calculation cycle and reference value to the cutoff control of all the semiconductor fuses 50 for which the control unit 11 is responsible. Alternatively, when changing the calculation cycle and reference value, the control unit 11 of the in-vehicle device 1 may apply the changed calculation cycle and reference value step by step in the cutoff control of all the semiconductor fuses 50 for which the control unit 11 is responsible according to the importance or priority of the in-vehicle load 6 to which these semiconductor fuses 50 are connected. For example, each in-vehicle load 6 has an importance level such as ASIL (Automotive Safety Integrity Level) determined according to the implemented function, etc., and the calculation cycle in which the in-vehicle load 6 with a higher level of ASIL is connected is smaller (shorter) than the calculation cycle in which the in-vehicle load 6 with a lower level is connected. The changed calculation cycle and reference value may be applied step by step.

[0082] The control unit 11 of the in-vehicle device 1 performs cutoff control on the semiconductor fuse 50 to be controlled by executing the processes from T101 to T105 in the same manner as in the first embodiment with the calculation cycle and reference value changed according to the CPU usage rate of the control unit 11 at the current time.

[0083] (Embodiment 4) FIG. 10 is an explanatory diagram illustrating a drive channel number table according to Embodiment 4. A drive channel number table is stored in the storage unit 12 of the in-vehicle device 1. The drive channel number table defines the relationship between the number of drive channels corresponding to the number of semiconductor fuses 50 that are on (closed state) among the semiconductor fuses 50 for which the control unit 11 is responsible for on-off control, and the calculation cycle corresponding to the number of drive channels (the number of on semiconductor fuses 50). The control unit 11 of the in-vehicle device 1 and each semiconductor fuse 50 are connected by a plurality of channels (terminals). The control unit 11 uses these plurality of channels to communicate with each semiconductor fuse 50, that is, to output control signals such as on commands or off commands, and to acquire sensor values such as current values.

[0084] For the management item of the number of drive channels (the number of in-vehicle loads 6 being driven), the number or range of the number of drive channels corresponding to the number of semiconductor fuses 50 in which the control unit 11 performs on / off control and which are in the on (closed state) is stored. For the management item of the operation cycle, the operation cycle corresponding to the number (range of numbers) of drive channels is stored. In the drive channel number table, the operation cycle is set to increase as the number of drive channels (the number of on semiconductor fuses 50) increases.

[0085] FIG. 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 constantly performs the following processing when the vehicle C is stopped or starting.

[0086] The control unit 11 of the in-vehicle device 1 acquires the number of semiconductor fuses 50 in the closed state (S401). The control unit 11 of the in-vehicle device 1 acquires the number of semiconductor fuses 50 in the on (closed state) at the current time by referring to, for example, the semiconductor fuse 50 table stored in the storage unit 12. The control unit 11 of the in-vehicle device 1 may also derive the number of drive channels by referring to the semiconductor fuse 50 table based on the number of semiconductor fuses 50 in the on (closed state) or the ID of the semiconductor fuse 50.

[0087] The control unit 11 of the in-vehicle device 1 refers to the drive channel number table and acquires the operation cycle 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 operation cycle corresponding to the acquired number of drive channels (the number of on semiconductor fuses 50).

[0088] In the drive channel number table, the operation cycle is set to increase as the number of drive channels (the number of on semiconductor fuses 50) increases. That is, when the number of drive channels (the number of on - semiconductor fuses 50) increases, the operation cycle also increases. As a result, the number of operations (execution count) executed in a predetermined processing unit time (predetermined period) decreases, and it is possible to suppress the processing load on the control unit 11 from becoming excessively high.

[0089] The control unit 11 of the in - vehicle device 1 specifies a reference value corresponding to the acquired operation cycle (S403). The control unit 11 of the in - vehicle device 1 changes the operation cycle and the reference value in executing the cutoff control (S404). The control unit 11 of the in - vehicle device 1 executes the processes from S403 to S404 in the same manner as from S303 to S304 in Embodiment 3.

[0090] (Embodiment 5) FIG. 12 is an explanatory diagram illustrating a vehicle scene table according to Embodiment 4. In the storage unit 12 of the in - vehicle device 1, a vehicle scene table is stored, and the vehicle scene table defines the relationship with the operation cycle corresponding to the vehicle operation state (vehicle scene). The vehicle scene table includes, as management items (fields), for example, the vehicle operation state and the operation cycle.

[0091] In the management item of the vehicle operation state, information (vehicle scene information) indicating the operation state (vehicle scene) of vehicle C is stored. 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 halted state, an autonomous driving state, a manual driving state, and a charging state, etc. Further, 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 and a low power consumption mode with lower power consumption than the normal mode. In the management item of the operation cycle, the operation cycle corresponding to the vehicle operation state (vehicle scene) is stored.

[0092] In the vehicle scene table, for example, the calculation cycle in the driving state may be set to be smaller (shorter) than the calculation cycle in the stopped state. Also, in the vehicle scene table, for example, the calculation cycle of in-vehicle device 1 in the normal mode may be set to be smaller (shorter) than the calculation cycle in the low power consumption mode. Also, in the vehicle scene table, for example, the calculation cycle in the automatic driving state may be set to be larger (longer) than the calculation cycle in the manual driving state. When vehicle C (vehicle scene) is in the automatic driving state, it is assumed that the processing load of control unit 11 of in-vehicle device 1 becomes higher than that in the manual driving state. By lengthening the calculation cycle, it is possible to suppress the processing load by control unit 11 from becoming excessively high.

[0093] Figure 13 is a flowchart illustrating the processing of control unit 11 of in-vehicle device 1. Control unit 11 of in-vehicle device 1 constantly performs the following processing when vehicle C is stopped or starting.

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

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

[0096] The control unit 11 of the in-vehicle device 1 specifies a reference value corresponding to the acquired operation cycle (S503). The control unit 11 of the in-vehicle device 1 changes the operation cycle and the reference value for performing the cutoff control (S504). The control unit 11 of the in-vehicle device 1 executes the processes from S503 to S504 in the same manner as from S303 to S304 in Embodiment 3.

[0097] The control unit 11 of the in-vehicle device 1 performs cutoff control on the semiconductor fuse 50 to be controlled by executing the processes from T101 to T105 in the same manner as in Embodiment 1, using the operation cycle and the reference value changed according to the current vehicle scene information.

[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 in Embodiments 1 to 5 when changing the operation cycle and the reference value based on the state information of the vehicle C. That is, 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, receive 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 operation cycle and the reference value by combining the received one or more change process forms.

[0099] When performing a combination of a plurality of change process forms, the control unit 11 of the in-vehicle device 1 also receives the priority order for performing the change process in the selected plurality of change process forms. When the change contents of the operation cycle and the reference value by each of these plurality of change process forms are different, the change content by the change process form with the higher priority may be applied. By combining a plurality of change process forms in this way, it is possible to derive an operation cycle and a reference value suitable for the overall state of the vehicle C at the current time.

[0100] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0101] Regarding the plurality of claims recited in the claims, regardless of the citation format, they can be combined with each other. In the claims, multiple dependent claims subordinate to a plurality of claims may be recited. Multiple dependent claims subordinate to multiple dependent claims may be recited. Even if no multiple dependent claims subordinate to multiple dependent claims are recited, this does not limit the recitation of multiple dependent claims subordinate to multiple dependent claims.

Explanation of Signs

[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 supply line 512 Current detection unit 513 Branch line 50 Semiconductor fuse 6 In-vehicle load

Claims

1. An in-vehicle device that performs cutoff control of one or more semiconductor fuses provided in a power supply line from a power supply device mounted on a vehicle, a control unit that performs processing related to the cutoff control of the semiconductor fuse, and a storage unit that stores a reference value used when the control unit performs processing, wherein the control unit acquires a current value flowing through the semiconductor fuse, determines whether or not to cut off the semiconductor fuse at a predetermined calculation cycle based on the reference value and the acquired current value, acquires state information regarding the state of the vehicle in parallel with the determination process of whether or not to cut off the semiconductor fuse, changes the calculation cycle and the reference value based on the acquired state information, and there are a plurality of combinations of the calculation cycle and the reference value In-vehicle device.

2. The storage unit stores correspondence information in which the correspondence between the calculation cycle and the reference value is associated, wherein the control unit derives a calculation cycle corresponding to the state information of the vehicle, and specifies a reference value corresponding to the derived calculation cycle by referring to the correspondence information The in-vehicle device according to claim 1.

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

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

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

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

7. The state information includes the number of in-vehicle loads being driven in each in-vehicle load to which each of the plurality of semiconductor fuses is connected, and the control unit changes the calculation cycle and the reference value by increasing the calculation cycle as the number of in-vehicle loads being driven increases The in-vehicle device according to claim 2.

8. The state information includes information indicating whether the in-vehicle device is in the normal mode or the low power consumption mode. The control unit changes the operation cycle and the reference value by making the operation cycle of the in-vehicle device in the normal mode smaller than the operation cycle in the low power consumption mode. The in-vehicle device according to claim 2.

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

10. In a computer including a storage unit that stores a reference value used when performing processing for performing cutoff control of one or more semiconductor fuses provided on a power supply line from a power supply device mounted on a vehicle, acquire the current value flowing through the semiconductor fuse, determine whether or not to cut off the semiconductor fuse at a predetermined operation cycle based on the reference value and the acquired current value, acquire state information regarding the state of the vehicle in parallel with the determination process of whether or not to cut off the semiconductor fuse, change the operation cycle and the reference value based on the acquired state information. An information processing method for executing the process.

11. In a computer including a storage unit that stores a reference value used when performing processing for performing cutoff control of one or more semiconductor fuses provided on a power supply line from a power supply device mounted on a vehicle, acquire the current value flowing through the semiconductor fuse, determine whether or not to cut off the semiconductor fuse at a predetermined operation cycle based on the reference value and the acquired current value, acquire state information regarding the state of the vehicle in parallel with the determination process of whether or not to cut off the semiconductor fuse, change the operation cycle and the reference value based on the acquired state information. A program for executing the process.

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