On-vehicle device, program, and information processing method

Abstract

To provide an on-vehicle device for controlling switching of a plurality of switching devices provided in a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided in the power supply line on an upstream side of the switching devices in a flow direction of a current from the power supply device.SOLUTION: In a vehicle, an on-vehicle device includes a control unit 11 for performing processing related to switching control of a switching device 52 and a semiconductor fuse 53. The control unit sets cutoff characteristics of the semiconductor fuse according to a state or characteristics of the switching device, and performs cutoff control of the semiconductor fuse or processing of causing a plurality of switching devices to transition to an open state according to the set cutoff characteristics.SELECTED DRAWING: Figure 2

Description

Technical Field

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

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.

[0003] The downstream semiconductor fuse has a control terminal. For example, when the downstream semiconductor fuse is a FET (Field Effect Transistor), the control terminal is the gate. The resistance value between both ends of the downstream semiconductor fuse changes according to the voltage of the control terminal. By adjusting the voltage of the control terminal, the resistance value between both ends of the downstream semiconductor fuse is adjusted to a sufficiently small value, and the downstream semiconductor fuse is switched on. By adjusting the voltage of the control terminal, the resistance value between both ends of the downstream semiconductor fuse is adjusted to a sufficiently large value, and the downstream semiconductor fuse is switched off.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the power supply control device described in Patent Document 1, consideration is not given to setting the cutoff characteristics of the semiconductor fuse according to the state of the switching device or the like.

[0006] 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 set the cutoff characteristics of a semiconductor fuse according to the state of an opening / closing device or the like.

Means for Solving the Problems

[0007] An in-vehicle device according to an embodiment of the present disclosure is an in-vehicle device that performs opening / closing control of a plurality of opening / closing devices provided on a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided on the power supply line on the upstream side of the opening / closing device in the current flow direction from the power supply device, and includes a control unit that performs processing related to the opening / closing control of the opening / closing device and the semiconductor fuse. The control unit sets the cutoff characteristics of the semiconductor fuse according to the state or characteristics of the opening / closing device, and performs cutoff control of the semiconductor fuse or processing for transitioning a plurality of the opening / closing devices to an open state with the set cutoff characteristics.

Effects of the Invention

[0008] According to one aspect of the present disclosure, it is possible to provide an in-vehicle device or the like that sets the cutoff characteristics of a semiconductor fuse according to the state of an opening / closing device or the like.

Brief Description of the Drawings

[0009]

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[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. Also, at least a part of the embodiments described below may be arbitrarily combined.

[0011] (1) An in-vehicle device according to one aspect of the present disclosure is an in-vehicle device that performs opening / closing control of a plurality of opening / closing devices provided on a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided on the power supply line on the upstream side of the opening / closing device in the current flow direction from the power supply device, and includes a control unit that performs processing related to opening / closing control of the opening / closing devices and the semiconductor fuse. The control unit sets the cutoff characteristics of the semiconductor fuse according to the state or characteristics of the opening / closing device, and performs cutoff control of the semiconductor fuse or processing for transitioning a plurality of the opening / closing devices to an open state with the set cutoff characteristics.

[0012] In this aspect, a plurality of switching devices are connected in parallel to a power supply line extending from a power supply device mounted on a vehicle. On the downstream side of the switching devices in the direction of current flow, an in-vehicle load or an in-vehicle ECU is connected. That is, a parallel circuit is configured by these plurality of switching devices connected in parallel. The control unit of the in-vehicle device functions as a power supply control device that controls the activation or deactivation of the in-vehicle load or the in-vehicle ECU. When performing the activation or deactivation, the control unit performs opening / closing control (on / off control) of the switching devices corresponding to these in-vehicle loads. In the power supply line extending from the power supply device, a semiconductor fuse is disposed between the power supply device and the plurality of switching devices. That is, the power supply line includes a main wire on which the semiconductor fuse is disposed, and a plurality of branch wires branched from the main wire and on which each of the switching devices is disposed. Therefore, a parallel circuit is configured by each of the branch wires on which each of the switching devices is disposed. Each of the branch wires is configured such that a relatively low load current flows therethrough. That is, the rated power consumption of in-vehicle loads or the like connected to each of the branch wires is configured to be relatively low power consumption among all the in-vehicle loads mounted on the vehicle. For each of these branch wires, a smoke emission characteristic is defined as a product specification or the like of the branch wire. The control unit of the in-vehicle device sets the cutoff characteristic of the semiconductor fuse according to the state or characteristic of the switching device. The state of the switching device is, for example, a closed state (on) or an open state (off). When controlling the activation or deactivation of an in-vehicle load or the like connected to the switching device, the control unit of the in-vehicle device causes the switching device to transition to on (closed) or off (open). At this time, the state information indicating whether the state of the switching device is a closed state (on) or an open state (off) is stored in the storage unit. The characteristic of the switching device is, for example, a rated maximum current value. In the storage unit of the in-vehicle device, the rated maximum current value of each of the switching devices is stored in advance. The control unit of the in-vehicle device can always optimize the cutoff characteristic of the semiconductor fuse according to the state or characteristic of each of the switching devices stored in the storage unit in this way, with respect to the state of each of the switching devices.By setting the cutoff characteristics in accordance with the state of each switching device in this way, it is possible to efficiently perform the cutoff control of the semiconductor fuse or the process of transitioning a plurality of switching devices to the open state (off). As a result, it is not necessary to arrange relatively expensive semiconductor fuses in each of the power supply lines (branch lines) with relatively small load currents, and by arranging switching devices (semiconductor relays) composed of relatively inexpensive FETs or mechanical relays, etc., the product cost can be reduced. The control unit of the in-vehicle device performs control processing related to the fuse function such as wire temperature calculation only on the semiconductor fuse (IPD: Intelligent Power Device) arranged on the main wire, that is, it is possible to eliminate the need to perform control processing related to the fuse function on the switching device (semiconductor relay) arranged on the branch line. Therefore, it is possible to reduce the arithmetic processing and power consumption by the control unit.

[0013] (2) In the in-vehicle device according to one aspect of the present disclosure, the state of the switching device includes a closed state in which power is supplied to an in-vehicle load connected downstream of the switching device in the direction of current flow from the power supply device, and an open state in which power to the in-vehicle load is cut off. The control unit sets the cutoff characteristics of the semiconductor fuse based on the load current flowing through each of the power supply lines where each of the closed switching devices among the plurality of switching devices is arranged.

[0014] In this aspect, the control unit of the in-vehicle device identifies the opening / closing device in the closed (on) state at the current time, and sets the breaking characteristics of the semiconductor fuse based on the load current flowing through the power line (branch line) where the identified closed-state opening / closing device is arranged. The value of the load current (load current value) flowing through each power line (branch line) where the opening / closing device is arranged is determined according to the rated power consumption of the in-vehicle load arranged on the power line (branch line), and may correspond to the current value assumed to flow through the power line (branch line) when the in-vehicle load operates normally. The load current value (rated current value based on the rated power consumption of the in-vehicle load) in each power line (branch line) is stored in advance in the storage unit in, for example, a table format (characteristic table). Since the opening / closing state of the opening / closing device changes according to the startup or stop of the in-vehicle load or the like, the control unit of the in-vehicle device sets the breaking characteristics of the semiconductor fuse in response to (following) the change in the opening / closing state of the opening / closing device. Thereby, the breaking characteristics of the semiconductor fuse can be efficiently set based on the load current of each power line (branch line) where each of the opening / closing devices in the closed state (on) is arranged, that is, each of the power lines (branch lines) that is energized at the current time.

[0015] (3) In the in-vehicle device according to one aspect of the present disclosure, the control unit sets the breaking characteristics of the semiconductor fuse to be lower than the fuming characteristics of the power line where the semiconductor fuse is arranged and higher than the total value of the load currents predetermined for each of the in-vehicle loads connected to each of the opening / closing devices in the closed state.

[0016] In this aspect, the control unit of the in-vehicle device sets the breaking characteristics of the semiconductor fuse so as to be lower (less than) than the smoke generation characteristics of the power line (main power line) where the semiconductor fuse is arranged. The control unit of the in-vehicle device may change the breaking characteristics of the conductor fuse, for example, by shifting the current value (diagram based on the current value) defined by the smoke generation characteristics up and down. Alternatively, the control unit of the in-vehicle device may set the breaking characteristics of the semiconductor fuse so as to be lower (less than) than the total value of the smoke generation characteristics of the power line (branch line) where the open / close device in the closed state is arranged. Thereby, the breaking control according to the breaking characteristics of the semiconductor fuse can be performed without exceeding the total value of the allowable values defined by the smoke generation characteristics of the power line (main power line) where the semiconductor fuse is arranged or the smoke generation characteristics of the power line (branch line) where the open / close device in the closed state is arranged, and protection can be provided from overcurrent in the case of a ground fault or the like occurring in any of the branch lines. Furthermore, the control unit of the in-vehicle device sets the breaking characteristics of the semiconductor fuse so as to be higher (greater than) than the total value of the load currents predetermined for each of the in-vehicle loads connected to each of the open / close devices in the closed state. In the power line (branch line) where the open / close device in the closed state is arranged, the total value of the load currents is set such that the rated power consumption of the in-vehicle loads connected to each of the power lines (branch lines) is lower than the total value of the smoke generation characteristics. Thereby, while reliably protecting from overcurrent in the case of a ground fault or the like occurring in the branch line, when a load current corresponding to the rated power consumption of the in-vehicle load flows, power supply to these in-vehicle loads can be performed without the semiconductor fuse being broken.

[0017] (4) In the in-vehicle device according to one aspect of the present disclosure, the characteristics of the open / close device include the maximum rated current value predetermined in the open / close device, and the control unit sets the breaking characteristics of the semiconductor fuse based on the maximum rated current value of the open / close device in the closed state among the plurality of open / close devices.

[0018] In this aspect, the characteristics of the switching device include the maximum rated current value. The maximum rated current value indicates the current value at which, in the switching device, element breakdown or the like is a concern (assumed) when a current equal to or greater than the maximum rated current value flows. The control unit of the in-vehicle device sets the cutoff characteristics of the semiconductor fuse based on the maximum rated current value of the switching device in the closed state (on) among the plurality of switching devices, so as to prevent an overcurrent exceeding the maximum rated current value from flowing in the switching device. Thus, even when using a relatively inexpensive switching device with a small maximum rated current value, the reliability of the entire in-vehicle system can be ensured.

[0019] (5) In the in-vehicle device according to one aspect of the present disclosure, the control unit identifies the switching device with the smallest maximum rated current value among the plurality of switching devices in the closed state, and sets the cutoff characteristics of the semiconductor fuse so as to be lower than the maximum rated current value of the identified switching device with the smallest value.

[0020] In this aspect, the maximum rated current value is preset for each of the plurality of switching devices, and it is assumed that the maximum rated current values of these switching devices are different values. Even in such a case, the control unit of the in-vehicle device identifies the switching device with the smallest maximum rated current value among the plurality of switching devices in the closed state, and sets the cutoff characteristics of the semiconductor fuse so as to be lower than the maximum rated current value of the identified switching device with the smallest value. Therefore, even when the plurality of switching devices are in the closed state during the same period, the reliability of the entire in-vehicle system can be ensured because the cutoff characteristics of the semiconductor fuse are set according to the switching device with the smallest maximum rated current value among them.

[0021] (6) In the in-vehicle device according to one aspect of the present disclosure, the maximum rated current value of the semiconductor fuse is greater than the maximum rated current value of the switching device with the largest maximum rated current value among the plurality of switching devices.

[0022] In this aspect, the maximum rated current value of the semiconductor fuse is configured to be larger than the maximum rated current value of the switching device with the largest maximum rated current value among all the switching devices to be controlled by the control unit of the in-vehicle device. That is, the maximum rated current value of any switching device is smaller than the maximum rated current value of the semiconductor fuse. When the switching device or the power supply line (branch line) to which the switching device is connected functions normally, it is possible to prevent the current flowing through the semiconductor fuse from exceeding the maximum rated current value of the semiconductor fuse. In the semiconductor fuse and the switching device, as the maximum rated current value increases, the component cost also tends to increase. By setting the maximum rated current value of each switching device connected to each in-vehicle load to be smaller than the maximum rated current value of the semiconductor fuse, a relatively inexpensive switching device can be used, thereby reducing the product cost.

[0023] (7) In the in-vehicle device according to one aspect of the present disclosure, the control unit acquires the current value flowing through the semiconductor fuse, and based on the set cutoff characteristics, performs cutoff control of the semiconductor fuse according to the acquired current value.

[0024] In this aspect, the control unit of the in-vehicle device acquires the current value flowing through the semiconductor fuse from a current detection unit such as a current sensor provided on the power line (main power line) where the semiconductor fuse is arranged, or from a current detection unit built into the IPD when the semiconductor fuse is composed of, for example, an IPD (Intelligent Power Device), at a predetermined period (sampling period). Based on the current values at a plurality of time points (detection time points) acquired at a predetermined period and the time (elapsed time) during which the current has flowed, the control unit of the in-vehicle device refers to the set cutoff characteristics of the semiconductor fuse to determine whether it is necessary to cut off the semiconductor fuse. When the period during which the current flows reaches a predetermined elapsed time (fusing time in the fuse) at the current value defined by the cutoff characteristics, the control unit of the in-vehicle device determines that it is necessary to cut off the semiconductor fuse and cuts off (opens: turns off) the semiconductor fuse. Thereby, the switching device and the power line (branch line) to which the switching device is connected can be protected from overcurrent.

[0025] (8) In the in-vehicle device according to one aspect of the present disclosure, when the control unit cuts off the semiconductor fuse based on the acquired current value and the set cutoff characteristics, the control unit performs a determination process as to whether an overcurrent factor is occurring in each of the power lines to which the plurality of switching devices are respectively connected.

[0026] In this aspect, based on the current value flowing through the semiconductor fuse and the cutoff characteristics, when the control unit of the in-vehicle device cuts off the semiconductor fuse, it is assumed that an overcurrent factor such as a ground fault has occurred in one of the power lines to which the switching device is connected. At this time, as a post-process of the cutoff process of the semiconductor fuse, the control unit of the in-vehicle device performs a determination process as to in which of the power lines (branch lines) to which the plurality of switching devices are respectively connected an overcurrent factor has occurred. By performing the determination process, the control unit of the in-vehicle device can perform a factor separation process for problem occurrence by identifying the power line (branch line) in which an overcurrent factor such as a ground fault has occurred.

[0027] In an in-vehicle device according to one aspect of the present disclosure, when performing determination processing regarding the overcurrent factor, the control unit opens all of the plurality of opening / closing devices, closes the semiconductor fuse, sequentially transitions each of the opening / closing devices in the open state to the closed state, acquires a current value flowing through the semiconductor fuse at the time of transition to the closed state, and determines whether or not an overcurrent factor has occurred in a power line where the opening / closing device transitioned to the closed state is disposed, based on the current value at the time of transition to the closed state.

[0028] In this aspect, when the control unit of the in-vehicle device shuts off the semiconductor fuse, when performing the determination process of the overcurrent factor, first, all the switching devices are set to the open state (off). Then, after the control unit of the in-vehicle device turns on the semiconductor fuse, each of the switching devices is sequentially transitioned to the closed state (on), and each time it is transitioned to the closed state (on), the current value flowing through the semiconductor fuse is acquired. As a result, without arranging a current sensor or the like on the power line (branch line) where the switching device is arranged, the current value flowing through each of these power lines (branch lines) can be acquired. In a power line (branch line) where a ground fault or the like that can be an overcurrent factor for shutting off the semiconductor fuse has occurred, when the switching device arranged on the power line (branch line) is transitioned from the open state (off) to the closed state (on), a ground fault current due to the ground fault will flow, and it is assumed that the ground fault current will be a large current with a substantially zero resistance value except for the impedance of the power line and the like. Based on the current value at the time of such transition to the closed state, the control unit of the in-vehicle device determines the presence or absence of an overcurrent factor in the power line where the switching device transitioned to the closed state is arranged, so that the power line (branch line) where an overcurrent factor such as a ground fault has occurred can be efficiently specified. The control unit of the in-vehicle device may fix the switching device arranged on the power line (branch line) specified as having an overcurrent factor such as a ground fault to the open state (off). Then, the control unit of the in-vehicle device may perform switching control on the switching devices arranged on other power lines (branch lines). As a result, the power line (branch line) specified as having an overcurrent factor such as a ground fault can be substantially disconnected from the in-vehicle system, and the drive control of the in-vehicle load and the like can be resumed (continued) using the normally operating switching devices and power lines (branch lines).

[0029] (10) In the in-vehicle device according to one aspect of the present disclosure, the switching device incorporates a protection circuit, and the control unit only performs processing related to the supply and interruption of power to the in-vehicle load connected to the switching device with respect to the switching device, and the protection processing in the power line to which the switching device is connected is performed by the protection circuit incorporated in the switching device.

[0030] In this aspect, the switching device incorporates a protection circuit that performs processes such as overcurrent interruption or overheat interruption, and is configured by, for example, an IPD (Intelligent Power Device). Even when the switching device is configured by an IPD or the like in this way, the control unit of the in-vehicle device only performs switching control according to the drive control of the in-vehicle load without exerting a fuse function on the switching device. Furthermore, the switching device configured by an IPD or the like performs self-protection such as overcurrent interruption or overheat interruption using the protection circuit provided in the switching device itself, so that for a short circuit such as a ground fault under the switching device in a relatively short time range, each switching device (IPD) is interrupted by self-protection. By adopting such a configuration, it is possible to protect the switching device (IPD) and the power supply line (branch line) to which the switching device is connected from overcurrent, and the control unit of the in-vehicle device can eliminate the need to exert a fuse function on these switching devices, thereby reducing the arithmetic load in the control unit.

[0031] (11) In the in-vehicle device according to one aspect of the present disclosure, the control unit detects a failure of the switching device or the semiconductor fuse based on the open / closed states of the switching device and the semiconductor fuse and the current value flowing through the semiconductor fuse.

[0032] In this aspect, the control unit of the in-vehicle device detects failures of the opening / closing device and the semiconductor fuse based on the opening / closing states of the opening / closing device and the semiconductor fuse and the value of the current flowing through the semiconductor fuse at a predetermined timing, such as when the vehicle is started or in a self-diagnosis mode by a diagnostic device or the like. The control unit of the in-vehicle device may determine whether the semiconductor fuse has an on-failure (stuck in the closed state) or an off-failure (stuck in the open state) based on the current flowing through the semiconductor fuse and the control signal (gate signal) output to the semiconductor fuse. When the control unit of the in-vehicle device determines that the semiconductor fuse has an on-failure (stuck in the closed state), for example, when the vehicle is stopped such as when parked and reduction of the dark current is required, it may turn all the opening / closing devices to the open state (off). The control unit of the in-vehicle device may determine whether any of the opening / closing devices has an on-failure (stuck in the closed state) or an off-failure (stuck in the open state) based on the current flowing through the semiconductor fuse after turning the semiconductor fuse to the closed state (on) and the control signals (gate signals) output to the respective opening / closing devices. When the control unit of the in-vehicle device determines that any of the opening / closing devices has an on-failure (stuck in the closed state), it may take corresponding measures by fixing the semiconductor fuse to the open state (off). By performing such processing, the control unit of the in-vehicle device can efficiently detect failures of the opening / closing device and the semiconductor fuse.

[0033] (12) An information processing method according to an aspect of the present disclosure causes a computer that controls opening / closing of a plurality of opening / closing devices provided on a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided on the power supply line upstream of the opening / closing device in the current flow direction from the power supply device to set a cutoff characteristic of the semiconductor fuse according to a state or characteristic of the opening / closing device, and execute a process of performing cutoff control of the semiconductor fuse or a process of transitioning the plurality of opening / closing devices to an open state with the set cutoff characteristic.

[0034] In this aspect, an information processing method can be provided that causes a computer to function as an in-vehicle device that sets the cutoff characteristics of a semiconductor fuse according to the state of an opening / closing device or the like.

[0035] (13) A program according to an aspect of the present disclosure causes a computer that controls the opening and closing of a plurality of opening / closing devices provided on a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided on the power supply line upstream of the opening / closing device in the current flow direction from the power supply device to set the cutoff characteristics of the semiconductor fuse according to the state or characteristics of the opening / closing device, and to perform a process of cutoff control of the semiconductor fuse or a process of transitioning the plurality of opening / closing devices to an open state with the set cutoff characteristics.

[0036] In this aspect, a program can be provided that causes a computer to function as an in-vehicle device that sets the cutoff characteristics of a semiconductor fuse according to the state of an opening / closing device or the like.

[0037] [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 include all modifications within the meaning and scope equivalent to the claims as indicated by the claims.

[0038] (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 including an in-vehicle device and the like according to Embodiment 1 (open / closed state of an opening / closing device). FIG. 2 is a block diagram illustrating the internal configuration of the in-vehicle device. 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.

[0039] 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 51. The power supply device 5 and the in-vehicle device 1 are not limited to being directly connected by the power line 51, 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.

[0040] The in-vehicle device 1 and a plurality of in-vehicle loads 6 or the in-vehicle ECU 2 are connected by a power line 51 (branch line 513), and the in-vehicle device 1 distributes power to these plurality of in-vehicle loads 6 or the in-vehicle ECU 2. That is, the in-vehicle device 1 functions as a power distribution device that distributes the power supplied from the power supply device 5 via the power line 51 to the plurality of in-vehicle loads 6 or the in-vehicle ECU 2 arranged on the downstream side in the direction of current flow.

[0041] The power line 51 extending from the power supply device 5 is connected to a semiconductor fuse 53 provided in the in-vehicle device 1. The power line 51 is located inside the in-vehicle device 1 and includes a main power line 511 to which the semiconductor fuse 53 is connected and a plurality of branch lines 513 branched from the main power line 511.

[0042] Between the semiconductor fuse 53 and the branch point where the main electric wire 511 branches into a plurality of branch wires 513, a current detection unit 512 is arranged. The current detection unit 512 periodically or constantly detects the value of the current (current value) flowing through the semiconductor fuse 53. The current detection unit 512 is, for example, a current sensor composed of a shunt resistor or the like, and outputs the detected current value to the control unit 11 of the in-vehicle device 1. When the semiconductor fuse 53 is composed of, for example, an IPD (Intelligent Power Device), the current detection unit 512 may be composed of a current sensor (sensor current detection unit) built in the IPD.

[0043] An opening / closing device 52 is arranged on each of the plurality of branch wires 513. The opening / closing device 52 is composed of, for example, a semiconductor relay, a mechanical relay, or an opening / closing switch. Therefore, a parallel circuit composed of a plurality of opening / closing devices 52 is formed by each of the opening / closing devices 52 arranged on each of the plurality of branch wires 513. That is, these plurality of opening / closing devices 52 are connected in parallel. The opening / closing devices 52 arranged on each of these branch wires 513 are arranged on the downstream side of the semiconductor fuse 53 in the current flow direction from the power supply line 51. On each of the plurality of branch wires 513, on the downstream side of the opening / closing device 52 in the current flow direction from the power supply line 51, an in-vehicle load 6 or an in-vehicle ECU 2 is connected.

[0044] 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 the detection value from the sensor or the output value from various switches. These in-vehicle loads 6 and the like are powered on or off in response to the opening / closing control (on / off control) of the opening / closing device 52 arranged on the branch wire 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 opening / closing devices 52.

[0045] 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 or the like. 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 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 various switches, sensors, or actuators may be connected to the in-vehicle device 1.

[0046] 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 by a CPU (Central Processing Unit) or an MPU (Micro Processing Unit) or the like, 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.

[0047] 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 be one that stores the 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.

[0048] The communication unit 13 is an input / output interface using a communication protocol such as CAN, CAN-FD, or Ethernet (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.

[0049] 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 signal lines 140 each extending to the semiconductor fuse 53, the current detection unit 512, and the opening / closing device 52 are connected to each of the terminals. 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.

[0050] The semiconductor fuse 53 is configured by an IPD (Intelligent Power Device) including a switching element such as a FET (Field Effect Transistor), for example. The control unit 11 of the in-vehicle device 1 performs cutoff control of the semiconductor fuse 53 according to the cutoff characteristics of the semiconductor fuse 53 based on the current value output from the current detection unit 512. Although details will be described later, the cutoff characteristics of the semiconductor fuse 53 are variably set according to the open / closed state or characteristics of each of the opening / closing devices 52.

[0051] FIG. 3 is an explanatory diagram showing a characteristic table of the opening / closing device 52. In a storage area accessible to the control unit 11 of the in-vehicle device 1, such as the storage unit 12 of the in-vehicle device 1, information regarding the opening / closing devices 52 arranged in each of the branch lines 513 is stored in, for example, a table format (characteristic table). The control unit 11 of the in-vehicle device 1 can acquire information regarding the load current, smoke generation characteristics, and characteristics of the opening / closing device 52 arranged in each of the branch lines 513 by referring to the characteristic table.

[0052] The characteristic table includes, as management items (fields), opening / closing device name, open / closed state, rated maximum current value, presence / absence of failure, branch line name, load current, smoke generation characteristics, presence / absence of ground fault, and in-vehicle load name. In the management item of the opening / closing device name, an identifier of the opening / closing device 52, such as a device number for uniquely indicating the opening / closing device 52, is stored.

[0053] In the management item of the open / closed state, the current open / closed state of the corresponding opening / closing device 52 (opening / closing device name) as the same record, that is, whether the opening / closing device 52 is closed (on) or open (off), is stored. Each time the control unit 11 of the in-vehicle device 1 performs opening / closing control on the opening / closing device 52, the control unit 11 can manage the current state of each of the opening / closing devices 52 by updating the information stored in the management item of the open / closed state.

[0054] In the management item of the rated maximum current value, the rated maximum current value of the switching device 52 (switching device name) corresponding as the same record is stored. The rated maximum current value is one of the values indicating the characteristics of the switching device 52, and indicates the current value at which element breakage or the like in the switching device 52 is concerned (assumed) when a current equal to or greater than the maximum rated current value flows. In the management item of the presence or absence of a fault, a value (none, present) indicating the presence or absence of a fault occurrence at the current time of the switching device 52 (switching device name) corresponding as the same record is stored. When indicating the occurrence of a fault, it may store an on-fault (stuck in the closed state) or an off-fault (stuck in the open state) which is the type of the fault. Each time the control unit 11 of the in-vehicle device 1 detects a fault with respect to the switching device 52, by updating the information stored in the management item of the presence or absence of a fault, the presence or absence of a current fault (during a fault or during normal operation) in each of the switching devices 52 can be managed.

[0055] In the management item of the branch line name, an identifier of the branch line 513 such as a line number for uniquely indicating each of the branch lines 513 located on the downstream side in the current flow direction from the main electric wire 511 where the semiconductor fuse 53 is arranged is stored. That is, in the management item of the branch line name, a line number or the like for uniquely indicating the branch line 513 where the switching device name corresponding as the same record is arranged is stored. Thereby, the correspondence between the branch line 513 and the switching device 52 arranged in the branch line 513 is associated and stored.

[0056] In the management item of the load current, data regarding the load current of the branch line 513 (branch line name) corresponding as the same record is stored. The data regarding the load current may be, for example, shown as a load current curve in a characteristic graph with the vertical axis being the current value (A) and the horizontal axis being the elapsed time (S). The load current curve may be continuously defined by a predetermined function, for example, or may be discretely defined using, for example, an array variable or the like, with the elapsed time as the array number and the current value as the value of the array variable. The load current may be determined according to the rated power consumption of the in-vehicle load 6 or the like connected to each of the branch lines 513.

[0057] In the management item of the smoke generation characteristics, data regarding the smoke generation characteristics of the branch line 513 (branch line name) corresponding as the same record is stored. The data regarding the smoke generation characteristics may be, for example, shown as a smoke generation characteristic curve in a characteristic graph with the vertical axis being the current value (A) and the horizontal axis being the elapsed time (S). The smoke generation characteristic curve may be, for example, continuously defined by a predetermined function, or may be discretely defined using, for example, an array variable or the like, with the elapsed time as the array number and the current value as the value of the array variable. As shown by the smoke generation characteristic curve, the larger the value of the current (overcurrent value) flowing through the branch line 513, the smaller the elapsed time indicating the smoke generation start time. Regarding the smoke generation characteristics, the smoke generation characteristics of the semiconductor fuse 53 are also stored in the storage unit 12.

[0058] In the management item of the presence or absence of a ground fault, a value (none, present) indicating the presence or absence of the occurrence of an overcurrent factor such as a ground fault at the current time of the branch line 513 corresponding as the same record is stored. Each time the control unit 11 of the in-vehicle device 1 performs a ground fault detection for the branch line 513, by updating the information stored in the management item of the presence or absence of a ground fault, the presence or absence of a ground fault (in a ground fault or in normal operation) at the current time for each branch line 513 can be managed.

[0059] In the management item of the in-vehicle load name, identifiers such as the device number of the in-vehicle load 6 or the like that is started or stopped by the opening / closing control (on / off control) of the opening / closing device 52 (opening / closing device name) corresponding as the same record, identifiers of the in-vehicle load 6 or the like are stored. That is, in the management item of the in-vehicle load name, identifiers of the in-vehicle load 6 or the like arranged on the branch line 513 (branch line name) corresponding as the same record are stored.

[0060] The control unit 11 of the in-vehicle device 1 identifies an in-vehicle load 6 or the like that starts or stops according to the received message or the like, and by referring to the characteristic table, identifies the branch line 513 and the opening / closing device 52 corresponding to the in-vehicle load 6. Thereby, the opening / closing device 52 arranged on the same branch line 513 as the in-vehicle load 6 can be identified. When the control unit 11 of the in-vehicle device 1 controls the identified opening / closing device 52 to open (off) or close (on), that is, changes the opening / closing state, in accordance with this control, the opening / closing state at the current time after the change is stored in the management item of the opening / closing state in the characteristic table. Thereby, the opening / closing state of each of the opening / closing devices 52 stored in the characteristic table can always be kept in the latest (current time) state.

[0061] In the present embodiment, the control unit 11 of the in-vehicle device 1 refers to the characteristic table to acquire the load current of the branch line 513 where the opening / closing device 52 in the closed (on) state is arranged at the current time, and sets (changes) the breaking characteristic of the semiconductor fuse 53 so as to exceed the load current. When there are a plurality of opening / closing devices 52 in the closed (on) state at the current time, the control unit 11 of the in-vehicle device 1 calculates the total value of the load currents of these plurality of opening / closing devices 52, and sets (changes) the breaking characteristic of the semiconductor fuse 53 so as to exceed the calculated total value of the load currents. At that time, the control unit 11 of the in-vehicle device 1 sets (changes) the breaking characteristic of the semiconductor fuse 53 so that the breaking characteristic is lower than the smoke generation characteristic of the main electric wire 511 where the semiconductor fuse 53 is arranged.

[0062] FIG. 4 is an explanatory diagram for explaining the breaking characteristic of the semiconductor fuse 53. The breaking characteristic of the semiconductor fuse 53 and the load currents in the branch line 513 and the opening / closing device 52 are both shown on a characteristic graph with the vertical axis representing the current value (A) and the horizontal axis representing the elapsed time (S). All the information shown on the characteristic graph is stored in the storage unit 12.

[0063] The cut-off characteristic is a characteristic of the semiconductor fuse 53 that includes the time (corresponding to the fusing time in the fuse) until the current is cut off when a current (overcurrent, fuse current) exceeding the rated current value flows through the semiconductor fuse 53. When the value of the current flowing through the semiconductor fuse 53 is equal to or less than the rated current value, the semiconductor fuse 53 continues to conduct the current equal to or less than the rated current value without being cut off.

[0064] The cut-off characteristic of the semiconductor fuse 53 is set as a variable characteristic value by the control unit 11 of the in-vehicle device 1 so that the current value can be shifted up and down in the vertical axis direction, that is, for the same elapsed time. When the cut-off characteristic of the semiconductor fuse 53 is high, the rated current value is also high, and the time until it cuts off against an overcurrent becomes longer. When the cut-off characteristic of the semiconductor fuse 53 is lowered, the rated current value also becomes lower, and the time until it cuts off against an overcurrent becomes shorter. That is, depending on the level of the cut-off characteristic, the product of the current value (overcurrent value) and the time until cut-off (current integrated value) varies.

[0065] The cut-off characteristic of the semiconductor fuse 53 is set to be higher than the load current of the branch line 513 where the switching device 52 in the closed (on) state is currently arranged, for example, by applying a predetermined offset value to the load current. In the illustration of this embodiment, the diagram showing the sum value of the load currents of the branch lines 513 where each of the switching devices 52 in the closed (on) state is currently arranged is shown as "bundled load current (a + b + c + d)". On top of that, the cut-off characteristic of the semiconductor fuse 53 is set to be lower than the smoke generation characteristic of the power supply line 51 (main power line 511) where the semiconductor fuse 53 is arranged.

[0066] In the illustration of the present embodiment, the diagram showing the smoke generation characteristics of the power line 51 (main power line 511) where the semiconductor fuse 53 is disposed is shown as "smoke generation characteristics" positioned at the top on the characteristic graph. In the illustration of the present embodiment, the diagram showing the cutoff characteristics of the semiconductor fuse 53 is shown as "semiconductor fuse 53 cutoff characteristics", positioned between the "bundled load current (a + b + c + d)" diagram positioned below and the "smoke generation characteristics" diagram positioned above. Each diagram showing each load current in each of the branch lines 513 (a, b, c, d) is shown as "each load current (a, b, c, d)", positioned below the "bundled load current (a + b + c + d)" diagram.

[0067] When the time until the current is cut off (fuse melting time) is the same when an overcurrent flows, the value of the overcurrent in the cutoff characteristics of the semiconductor fuse 53 is lower than the value of the overcurrent in the smoke generation characteristics of the main power line 511. Moreover, the value of the overcurrent in the cutoff characteristics of the semiconductor fuse 53 is higher than the total value of the current values of the load currents in each of the branch lines 513 where the opening / closing device 52 in the closed state (on) is disposed. Thereby, the cutoff characteristics of the semiconductor fuse 53 can be set according to the state of the opening / closing device 52 and the like, and cutoff control can be performed according to the cutoff characteristics of the semiconductor fuse 53. For example, when a ground fault occurs, while reliably protecting the branch lines 513 from overcurrent, it is possible to eliminate the need to dispose the semiconductor fuse 53 in all the branch lines 513, and it is possible to reduce the product cost and the like.

[0068] FIG. 5 is a flowchart exemplifying 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.

[0069] The control unit 11 of the in-vehicle device 1 identifies the opening / closing device 52 in the closed (on) state (the opening / closing device 52 in the closed state) (S101). The in-vehicle device 1 functions as a power control device that controls the supply or cutoff of power to the in-vehicle load 6 or the in-vehicle ECU 2 connected to the opening / closing device 52, that is, the startup or stop of the in-vehicle load 6 or the in-vehicle ECU 2, by performing opening / closing control (on / off control) of the opening / closing device 52 connected by the signal line 140. The in-vehicle device 1 that functions as a power control device identifies, for example, the in-vehicle load 6 etc. to be started or stopped by acquiring a message received via the in-vehicle network 3 or an output value from various sensors connected to the in-vehicle device 1 (triggered by the reception of the message or the output value), and performs opening / closing control (on / off control) of the opening / closing device 52 connected to the in-vehicle load 6 etc.

[0070] When performing opening / closing control (on / off control) of the opening / closing device 52, the control unit 11 of the in-vehicle device 1 may update the opening / closing state of each opening / closing device 52 in the characteristic table stored in the storage unit 12, for example, according to the execution of the opening / closing control. Thus, the control unit 11 of the in-vehicle device 1 constantly performs opening / closing control (on / off control) of the opening / closing device 52, and identifies the opening / closing device 52 in the closed (on) state at the current time (the opening / closing device 52 in the closed state) by referring to the characteristic table, for example.

[0071] The control unit 11 of the in-vehicle device 1 acquires the load current of the power line 51 (branch line 513) where the closed opening / closing device 52 is arranged (S102). The control unit 11 of the in-vehicle device 1 acquires the load current of each power line 51 (branch line 513) where all the opening / closing devices 52 in the closed (on) state are arranged, respectively, by referring to the characteristic table, for example.

[0072] Regarding the opening / closing device 52 in the closed (on) state, depending on the operating state of the vehicle C, not only the case where only a single opening / closing device 52 out of any of the opening / closing devices 52 is closed (on), but also the case where a plurality of opening / closing devices 52 are closed (on) is assumed. Or, the case where all the opening / closing devices 52 are in the open (off) state is also assumed. The control unit 11 of the in-vehicle device 1 acquires the load currents corresponding to all the opening / closing devices 52 in the closed (on) state, and calculates the total load current by summing these load currents. When there is one opening / closing device 52 in the closed state, the total load current corresponds to the load current of the branch line 513 where the opening / closing device 52 is arranged. When there are two or more opening / closing devices 52 in the closed state, the total load current corresponds to the sum value of the load currents of the respective branch lines 513 where these two or more opening / closing devices 52 are arranged.

[0073] In the present embodiment, the total load current may be calculated (derived) by summing the current values indicated by the load currents (load current curves) of the respective branch lines 513 to be summed according to the values of the corresponding elapsed time. That is, in the characteristic graph, the load current characteristic may be calculated (derived) by summing the load current curves of the respective branch lines 513 in the direction of the current value.

[0074] The control unit 11 of the in-vehicle device 1 changes the breaking characteristic of the semiconductor fuse 53 according to the acquired load current (S103). The control unit 11 of the in-vehicle device 1 changes the breaking characteristic of the semiconductor fuse 53 according to the acquired load current, that is, according to the load current (total load current) of the branch line 513 where the opening / closing device 52 in the closed (on) state is arranged. Then, the breaking characteristic is set so that the breaking characteristic of the semiconductor fuse 53 is lower than the breaking characteristic of the main electric wire 511 where the semiconductor fuse 53 is arranged.

[0075] The control unit 11 of the in-vehicle device 1 derives the cutoff characteristics (a diagram showing the cutoff characteristics) of the semiconductor fuse 53 by using an offset value for exceeding the load current of the branch line 513, that is, the combined load current caused by these branch lines 513 when there are a plurality of target branch lines 513. The offset value is stored in the storage unit 12, and values preset so as to be lower than the cutoff characteristics of the main electric wire 511 where the semiconductor fuse 53 is arranged may be used, and the like.

[0076] By using the offset value for the current value (load current curve) indicated by the combined load current in this way, the cutoff characteristics (cutoff characteristic curve) of the semiconductor fuse 53 that exceed the current value of the load current curve can be derived. The control unit 11 of the in-vehicle device 1 stores the derived cutoff characteristic curve that exceeds the combined load current in the storage unit 12, and sets (changes) the cutoff characteristics of the semiconductor fuse 53 by using the derived cutoff characteristic curve.

[0077] The control unit 11 of the in-vehicle device 1 acquires the current value flowing through the semiconductor fuse 53 (S104). The control unit 11 of the in-vehicle device 1 acquires the current value (sense current) flowing through the semiconductor fuse 53 from a current detection unit 512 such as a current sensor provided in the main electric wire 511 where the semiconductor fuse 53 is arranged. The control unit 11 of the in-vehicle device 1 acquires the elapsed time during which current has flowed through the semiconductor fuse 53 at the acquired current value by periodically acquiring the current value from the semiconductor fuse 53.

[0078] The control unit 11 of the in-vehicle device 1 determines whether to cut off the semiconductor fuse 53 based on the changed cutoff characteristics and the acquired current value (S105). The control unit 11 of the in-vehicle device 1 determines whether to cut off the semiconductor fuse 53 based on the cutoff characteristics changed in the above-described process, that is, the cutoff characteristics set at the current time.

[0079] The control unit 11 of the in-vehicle device 1 determines whether the current value from the current detection unit 512 (the current value flowing through the semiconductor fuse 53) is less than the minimum current value defined by the cutoff characteristic curve. If it is less than the minimum current value in the cutoff characteristic curve, that is, the current value flowing through the semiconductor fuse 53 is equal to or less than the rated current of the semiconductor fuse 53 and is a current value at which the semiconductor fuse 53 is not cut off, the control unit 11 of the in-vehicle device 1 determines not to cut off the semiconductor fuse 53. When it is determined not to cut off the semiconductor fuse 53, the closed (on) state of the semiconductor fuse 53 is maintained.

[0080] The control unit 11 of the in-vehicle device 1 determines whether the current value from the current detection unit 512 (the current value flowing through the semiconductor fuse 53) is equal to or greater than the minimum rated current value defined by the cutoff characteristic curve, and whether the elapsed time when the current flows at the current value has reached the elapsed time corresponding to the current value defined by the cutoff characteristic curve (corresponding to the fusing time of the fuse). If it has not reached, the control unit 11 of the in-vehicle device 1 determines not to cut off the semiconductor fuse 53. If it has reached, the control unit 11 of the in-vehicle device 1 determines to cut off the semiconductor fuse 53. The control unit 11 of the in-vehicle device 1 may periodically acquire the current value from the current detection unit 512 (the current value flowing through the semiconductor fuse 53), calculate the current integration value by multiplying the elapsed time when the current flows by the current value, and determine whether to cut off the semiconductor fuse 53 based on the current integration value.

[0081] When it is determined not to cut off (S105: NO), the control unit 11 of the in-vehicle device 1 determines whether the opening / closing state of each of the opening / closing devices 52 has been changed (S107). When it is determined not to cut off the semiconductor fuse 53, the control unit 11 of the in-vehicle device 1 determines whether the opening / closing state of each of the opening / closing devices 52 has been changed.

[0082] The in-vehicle device 1 that functions as a power control device constantly controls the activation or deactivation of the in-vehicle load 6 or the in-vehicle ECU 2 using the received message or output value as a trigger, and performs opening / closing control (on / off control) of the opening / closing device 52 according to the activation or deactivation. Therefore, the control unit 11 of the in-vehicle device 1 determines whether the opening / closing device 52 in the closed state specified in S101 is the same as the opening / closing device 52 in the closed state at the current time. If they are the same, the control unit 11 of the in-vehicle device 1 determines that the opening / closing state of each opening / closing device 52 has not been changed. If they are not the same, the control unit 11 of the in-vehicle device 1 determines that the opening / closing state of each opening / closing device 52 has been changed.

[0083] When it is determined that the opening / closing state has been changed (S107: YES), the control unit 11 of the in-vehicle device 1 performs a loop process to execute the process from S101 again. When it is determined that the opening / closing state of each opening / closing device 52 has been changed with respect to the state specified in S101, the control unit 11 of the in-vehicle device 1 performs a loop process to execute the process from S101 again. As a result, the opening / closing device 52 (the opening / closing device 52 in the closed state) in the closed (on) state at the current time is specified, and subsequent processes are carried out. Following the opening / closing control (on / off control) of the opening / closing device 52, the cutoff characteristics of the semiconductor fuse 53 can be changed in a timely manner. Therefore, the control unit 11 of the in-vehicle device 1 can synchronize the opening / closing control (on / off control) of the opening / closing device 52 and the change control of the cutoff characteristics of the semiconductor fuse 53, and can function as a power control device while maintaining the cooperation of these controls.

[0084] When it is determined that the opening / closing state has not been changed (S107: NO), the control unit 11 of the in-vehicle device 1 performs a loop process to execute the process from S104 again. When it is determined that the opening / closing state of each opening / closing device 52 has not been changed with respect to the state specified in S101, the control unit 11 of the in-vehicle device 1 performs a loop process to execute the process from S104 again. As a result, the control unit 11 of the in-vehicle device 1 continues the cutoff control for the semiconductor fuse 53 using the cutoff characteristics at the current time.

[0085] When it is determined to cut off (S105: YES), the control unit 11 of the in-vehicle device 1 cuts off the semiconductor fuse 53 (S106). When it is determined to cut off the semiconductor fuse 53, the control unit 11 of the in-vehicle device 1 cuts off the semiconductor fuse 53, for example, by stopping the application of voltage to the gate terminal of the semiconductor fuse 53. Alternatively, the control unit 11 of the in-vehicle device 1 may turn all the opening / closing devices 52 to the open state (off). As a result, the current to the branch line 513 located downstream of the semiconductor fuse 53 (main electric wire 511) is cut off, so that the state where an overcurrent flows through the branch line 513 is eliminated, and for example, smoking in the branch line 513 due to a ground fault or the like or a failure of the in-vehicle load 6 or the like connected to the branch line 513 can be effectively prevented.

[0086] The control unit 11 of the in-vehicle device 1 identifies the branch line 513 where the overcurrent factor has occurred (S108). For example, the branch line 513 where an overcurrent factor such as a ground fault has occurred can occur not only in the branch line 513 where the opening / closing device 52 in the closed state (on) is arranged, but also in the branch line 513 where the opening / closing device 52 in the open state (off) is arranged. Therefore, after cutting off the semiconductor fuse 53, the control unit 11 of the in-vehicle device 1 causes all the opening / closing devices 52 to transition to the open state (off). As a result, the semiconductor fuse 53 and all the opening / closing devices 52 are all in the open state (off) at one end. Thereafter, the control unit 11 of the in-vehicle device 1 fixes the semiconductor fuse 53 in the closed state (on), and each of the opening / closing devices 52 is sequentially transitioned to the closed state (on), and each time it is transitioned to the closed state (on), the current value flowing through the semiconductor fuse 53 is acquired.

[0087] When the control unit 11 of the in-vehicle device 1 sequentially transitions each of the opening / closing devices 52 to the closed state (on), the control unit 11 of the in-vehicle device 1 may turn off the opening / closing device 52 that was previously set to the closed state (on) before the opening / closing device 52 that is to be transitioned to the closed state (on) this time. In this case, if the value of the current flowing through the semiconductor fuse 53 is substantially the same as the value of the load current of the branch line 513 where the opening / closing device 52 that is to be transitioned to the closed state (on) this time is arranged, the control unit 11 of the in-vehicle device 1 determines that no overcurrent factor such as a ground fault has occurred in the branch line 513. When the value of the current flowing through the semiconductor fuse 53 exceeds the value of the load current of the branch line 513 where the opening / closing device 52 that is to be transitioned to the closed state (on) this time is arranged, the control unit 11 of the in-vehicle device 1 determines that an overcurrent factor such as a ground fault has occurred in the branch line 513.

[0088] When the control unit 11 of the in-vehicle device 1 sequentially transitions each of the opening / closing devices 52 to the closed state (on), the control unit 11 of the in-vehicle device 1 may also maintain the closed state (on) for the opening / closing device 52 that was previously set to the closed state (on) before the opening / closing device 52 that is to be transitioned to the closed state (on) this time. In this case, if the value of the current flowing through the semiconductor fuse 53 is substantially the same as the sum of the load current of the branch line 513 where the opening / closing device 52 that is to be transitioned to the closed state (on) this time is arranged and the load current of the branch line 513 where the opening / closing device 52 that was transitioned to the closed state (on) until the previous time is arranged, the control unit 11 of the in-vehicle device 1 determines that no overcurrent factor such as a ground fault has occurred in the branch line 513. When the value of the current flowing through the semiconductor fuse 53 exceeds the sum of the load currents, the control unit 11 of the in-vehicle device 1 determines that an overcurrent factor such as a ground fault has occurred in the branch line 513.

[0089] The control unit 11 of the in-vehicle device 1 may change the value stored in the ground fault presence / absence management item of the characteristic table stored in the storage unit 12 for the branch line 513 identified as having an overcurrent cause such as a ground fault. Thereby, at the current time, it is possible to grasp or manage at which branch line 513 an overcurrent cause such as a ground fault has occurred. The control unit 11 of the in-vehicle device 1 fixes the switching device 52 arranged on the branch line 513 identified as having an overcurrent cause such as a ground fault in the open state (off). Then, the control unit 11 of the in-vehicle device 1 may perform opening / closing control on the switching devices 52 arranged on the other power lines 51 (branch lines 513).

[0090] As a post-processing in the cutoff process of the semiconductor fuse 53, the control unit 11 of the in-vehicle device 1 may perform a specific process of an overcurrent cause such as a ground fault in the branch line 513, and perform failure detection for each of the switching devices 52 using the same method as the specific process. The control unit 11 of the in-vehicle device 1 performs failure detection of the switching device 52 and the semiconductor fuse 53 based on, for example, the opening / closing state of the switching device 52 and the semiconductor fuse 53 and the current value flowing through the semiconductor fuse 53 at a predetermined timing such as when the vehicle C is started or in a self-diagnosis mode by a diagnostic device or the like.

[0091] Based on the current flowing through the semiconductor fuse 53 and the control signal (gate signal) output to the semiconductor fuse 53, the control unit 11 of the in-vehicle device 1 may determine whether the semiconductor fuse 53 has an on-failure (stuck in the closed state) or an off-failure (stuck in the open state). In this case, the control unit 11 of the in-vehicle device 1 turns on any one of the switching devices 52, and then transmits an on-signal or an off-signal as a control signal to the semiconductor fuse 53, and performs failure detection based on the output state of the signal and the current value flowing through the semiconductor fuse 53.

[0092] Although the control unit 11 of the in-vehicle device 1 has not output an on signal to the semiconductor fuse 53, when the current value flowing through the semiconductor fuse 53 exceeds 0 A (detecting that current is flowing), it determines that there is an on-failure (stuck in the closed state). Although the control unit 11 of the in-vehicle device 1 has not output an off signal to the semiconductor fuse 53, when the current value flowing through the semiconductor fuse 53 is 0 A (detecting that no current is flowing), it determines that there is an off-failure (stuck in the open state).

[0093] The control unit 11 of the in-vehicle device 1 may determine whether the switching device 52 has an on-failure (stuck in the closed state) or an off-failure (stuck in the open state) based on the current flowing through the semiconductor fuse 53 and the control signals (gate signals) output to each of the switching devices 52. In this case, the control unit 11 of the in-vehicle device 1 closes (turns on) the semiconductor fuse 53 and then sequentially transmits an on signal or an off signal as a control signal to each of the switching devices 52, and performs failure detection based on the output state of the signal and the current value flowing through the semiconductor fuse 53.

[0094] Although the control unit 11 of the in-vehicle device 1 has not output an on signal to the switching device 52, when the current value flowing through the semiconductor fuse 53 exceeds 0 A (detecting that current is flowing), it determines that the switching device 52 has an on-failure (stuck in the closed state). Although the control unit 11 of the in-vehicle device 1 has not output an off signal to the switching device 52, when the current value flowing through the semiconductor fuse 53 is 0 A (detecting that no current is flowing), it determines that the switching device 52 has an off-failure (stuck in the open state). The control unit 11 of the in-vehicle device 1 updates the management item of the presence or absence of failure in the characteristic table based on the result of failure detection for each of the switching devices 52.

[0095] (Embodiment 2) FIG. 6 is an explanatory diagram for explaining the interruption characteristics of the semiconductor fuse 53 according to Embodiment 2 (characteristics of the opening / closing device 52). The interruption characteristics of the semiconductor fuse 53 in the present embodiment are calculated as the sum of the load currents of the plurality of opening / closing devices 52, and are set (changed) to exceed the calculated sum value of the load currents, similar to the interruption characteristics of Embodiment 1. Furthermore, the interruption characteristics of the semiconductor fuse 53 are set (changed) to be lower than the rated maximum current of the opening / closing device 52 (semiconductor relay). The rated maximum current of the opening / closing device 52 (semiconductor relay) is preset to be lower than the smoke generation characteristics of the main electric wire 511 where the semiconductor fuse 53 is disposed.

[0096] On the characteristic graph with the vertical axis representing the current value (A) and the horizontal axis representing the elapsed time (S), similar to Embodiment 1, the diagram showing the rated maximum current of the opening / closing device 52 (semiconductor relay) is indicated as "semiconductor relay (rated maximum current)". The diagram "semiconductor fuse 53 interruption characteristics" showing the interruption characteristics of the semiconductor fuse 53 is located between the diagram "summed load current (a + b + c + d)" located below and the diagram "semiconductor relay (rated maximum current)" located above. The diagram "semiconductor relay (rated maximum current)" is located below the diagram "smoke generation characteristics" showing the smoke generation characteristics of the power supply line 51 (main electric wire 511) where the semiconductor fuse 53 is disposed.

[0097] The rated maximum current of the opening / closing device 52 (semiconductor relay) is stored in the management item of the rated maximum current value in the characteristic table stored in the storage unit 12. The control unit 11 of the in-vehicle device 1 derives the interruption characteristics of the semiconductor fuse 53 using the rated maximum current of the opening / closing device 52 with the minimum rated maximum current among the opening / closing devices 52 (semiconductor relays) in the closed state (on). That is, the interruption characteristics of the semiconductor fuse 53 are set to be lower than the rated maximum current of the opening / closing device 52 with the minimum rated maximum current among the opening / closing devices 52 (semiconductor relays) in the closed state (on).

[0098] FIG. 7 is a flowchart exemplifying 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. The control unit 11 of the in-vehicle device 1 identifies the opening / closing device 52 in the closed (on) state (the opening / closing device 52 in the closed state) (S201). The control unit 11 of the in-vehicle device 1 performs the processing of S201 in the same manner as the processing S101 of Embodiment 1.

[0099] The control unit 11 of the in-vehicle device 1 acquires the rated maximum current of the power line 51 (branch line 513) where the opening / closing device 52 in the closed state is arranged (S202). The control unit 11 of the in-vehicle device 1 acquires the rated maximum current of all the opening / closing devices 52 in the closed (on) state, for example, by referring to the characteristic table. The control unit 11 of the in-vehicle device 1 identifies the minimum rated maximum current among these acquired one or more rated maximum currents.

[0100] The control unit 11 of the in-vehicle device 1 changes the cutoff characteristic of the semiconductor fuse 53 according to the acquired minimum rated maximum current (S203). The control unit 11 of the in-vehicle device 1 changes (sets) the cutoff characteristic of the semiconductor fuse 53 so as to be lower than the acquired minimum rated maximum current. Then, the control unit 11 of the in-vehicle device 1 may acquire and sum up the load currents corresponding to all the opening / closing devices 52 in the closed (on) state and change (set) the cutoff characteristic of the semiconductor fuse 53 so as to exceed the sum load current, in the same manner as the processing S102 and S103 of Embodiment 1.

[0101] The control unit 11 of the in-vehicle device 1 acquires the current value flowing through the semiconductor fuse 53 (S204). The control unit 11 of the in-vehicle device 1 determines whether to cut off the semiconductor fuse 53 based on the changed cutoff characteristic and the acquired current value (S205). The control unit 11 of the in-vehicle device 1 cuts off the semiconductor fuse 53 (S206). The control unit 11 of the in-vehicle device 1 determines whether the opening / closing state of each of the opening / closing devices 52 has been changed (S207). The control unit 11 of the in-vehicle device 1 identifies the branch line 513 where the overcurrent factor has occurred (S208). The control unit 11 of the in-vehicle device 1 performs the processing from S204 to S208 in the same manner as the processing from S104 to S108 of Embodiment 1.

[0102] (Embodiment 3) FIG. 8 is a schematic diagram illustrating the configuration of an in-vehicle system S including an in-vehicle device 1 and the like according to Embodiment 3 (where the opening / closing device 52 is configured by an IPD). Similar to Embodiment 1, the in-vehicle system S in the present embodiment includes an in-vehicle device 1 including a semiconductor fuse 53 and a plurality of opening / closing devices 52. The semiconductor fuse 53 is configured by, for example, an IPD (Intelligent Power Device) as in Embodiment 1.

[0103] The opening / closing device 52 in the present embodiment is also configured by, for example, an IPD and includes a protection circuit that performs processes such as overcurrent interruption or overheat interruption. Then, the control unit 11 of the in-vehicle device 1 does not perform a process for executing the fuse function in the opening / closing device 52, and only performs opening / closing control on the opening / closing device 52 in accordance with the drive control for the in-vehicle load 6 connected to the opening / closing device 52 via the branch line 513.

[0104] The opening / closing device 52 configured by an IPD or the like performs self-protection such as overcurrent interruption or overheat interruption using the protection circuit provided in the opening / closing device 52 itself. By adopting such a configuration, while it is unnecessary for the control unit 11 of the in-vehicle device 1 to execute the fuse function for each opening / closing device 52, for a short circuit such as a ground fault under the opening / closing device 52 in a relatively short time region, each opening / closing device 52 (IPD) interrupts by self-protection, thereby protecting against the overcurrent flowing through the branch line 513. The control unit 11 of the in-vehicle device 1 also applies the processes shown in Embodiment 1 or 2 in the in-vehicle system S shown in the present embodiment, sets the interruption characteristics of the semiconductor fuse 53 according to the state or characteristics of the opening / closing device 52, and performs interruption control of the semiconductor fuse 53.

[0105] FIG. 9 is an explanatory diagram for explaining the breaking characteristics of the semiconductor fuse 53. The breaking characteristics of the semiconductor fuse 53 in the present embodiment are calculated in the same manner as the breaking characteristics of the first or second embodiment, and are set (changed) to exceed the total value of the load currents of the plurality of switching devices 52. Diagrams showing the breaking characteristics, load current, rated maximum current, etc. of the semiconductor fuse 53 are the same as those of the first or second embodiment.

[0106] For example, a diagram showing the breaking threshold of the protection circuit included in the switching device 52 configured by IPD is shown linearly as "overcurrent breaking and overheat breaking of loads (a, b, c, d)". A diagram showing the breaking threshold of the protection circuit of the semiconductor fuse 53 is shown linearly as "overcurrent breaking and overheat breaking of the semiconductor fuse 53". The diagram showing "overcurrent breaking and overheat breaking of the semiconductor fuse 53" is located above the diagram showing "overcurrent breaking and overheat breaking of loads (a, b, c, d)". That is, the breaking threshold of the protection circuit of the semiconductor fuse 53 is set to a value higher than the breaking threshold of the protection circuit included in the switching device 52 (IPD). The diagram showing "overcurrent breaking and overheat breaking of the semiconductor fuse 53" and the diagram showing "overcurrent breaking and overheat breaking of loads (a, b, c, d)" are set to be located above the breaking characteristics (breaking characteristic curve) of the semiconductor fuse 53 in part. By setting the characteristics of the semiconductor fuse 53 and the switching device 52 (IPD) in this way, a vehicle-mounted system S with high robustness against overcurrents in the branch line 513 can be constructed.

[0107] It should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above meaning but by the claims, and it is intended that all changes within the meaning and scope equivalent to the claims are included.

[0108] 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 claim subordinate to a multiple dependent claim is recited, this does not limit the recitation of multiple dependent claims subordinate to a multiple dependent claim.

Description of Reference Numerals

[0109] C Vehicle S In-vehicle System 1 In-vehicle Device (Power Control 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 51 Power Supply Line 511 Main Power Line 512 Current Detection Unit 513 Branch Line 52 Switching Device (FET, Semiconductor Relay) 53 Semiconductor Fuse (IPD) 6 In-vehicle Load

Claims

1. An in-vehicle device that performs opening / closing control of a plurality of opening / closing devices provided in a power line from a power supply device mounted on a vehicle and a semiconductor fuse provided in the power line upstream of the opening / closing devices in the current flow direction from the power supply device, comprising a control unit that performs processing related to the opening / closing control of the opening / closing devices and the semiconductor fuse, wherein the control unit sets the cutoff characteristics of the semiconductor fuse according to the state or characteristics of the opening / closing devices, and performs cutoff control of the semiconductor fuse or a process of transitioning a plurality of the opening / closing devices to an open state with the set cutoff characteristics In-vehicle device.

2. The state of the opening / closing device includes a closed state in which power is supplied to an in-vehicle load connected downstream of the opening / closing device in the current flow direction from the power supply device, and an open state in which power to the in-vehicle load is cut off, and the control unit sets the cutoff characteristics of the semiconductor fuse based on the load current flowing through each of the power lines where each of the opening / closing devices in the closed state is arranged among the plurality of opening / closing devices. The in-vehicle device according to claim 1.

3. The control unit sets the cutoff characteristics of the semiconductor fuse to be lower than the smoke generation characteristics of the power line where the semiconductor fuse is arranged and higher than the total value of the load currents predetermined for each of the in-vehicle loads connected to each of the opening / closing devices in the closed state. The in-vehicle device according to claim 2.

4. The characteristics of the opening / closing device include a maximum rated current value predetermined in the opening / closing device, and the control unit sets the cutoff characteristics of the semiconductor fuse based on the maximum rated current value of the opening / closing devices in the closed state among the plurality of opening / closing devices. The in-vehicle device according to claim 1.

5. The control unit identifies the opening / closing device with the smallest maximum rated current value among the plurality of opening / closing devices in the closed state, and sets the cutoff characteristics of the semiconductor fuse to be lower than the maximum rated current value of the opening / closing device with the smallest value. The in-vehicle device according to claim 4.

6. The maximum rated current value of the semiconductor fuse is larger than the maximum rated current value of the opening / closing device with the largest maximum rated current value among the plurality of opening / closing devices. The in-vehicle device according to claim 4.

7. The control unit acquires the current value flowing through the semiconductor fuse, and performs cutoff control of the semiconductor fuse according to the acquired current value based on the set cutoff characteristics. The in-vehicle device according to any one of claims 1 to 6.

8. The control unit Based on the acquired current value and the set cutoff characteristics, when the semiconductor fuse is cut off, Determination processing is performed to determine whether an overcurrent factor is occurring in each of the power supply lines to which a plurality of the opening / closing devices are respectively connected. The in-vehicle device according to claim 7.

9. The control unit In performing the determination processing regarding the overcurrent factor, all of the opening / closing devices in the plurality of opening / closing devices are set to the open state, and the semiconductor fuse is set to the closed state. Each of the opening / closing devices in the open state is sequentially transitioned to the closed state, and the current value flowing through the semiconductor fuse at the time of the transition to the closed state is acquired. Based on the current value at the time of the transition to the closed state, it is determined whether an overcurrent factor is occurring in the power supply line where the opening / closing device transitioned to the closed state is arranged. The in-vehicle device according to claim 8.

10. The opening / closing device incorporates a protection circuit The control unit only performs processing related to the supply and cutoff of power to the in-vehicle load connected to the opening / closing device with respect to the opening / closing device. The protection processing in the power supply line to which the opening / closing device is connected is performed by the protection circuit incorporated in the opening / closing device. The in-vehicle device according to claim 7.

11. The control unit detects a failure of the opening / closing device or the semiconductor fuse based on the open / closed states of the opening / closing device and the semiconductor fuse and the current value flowing through the semiconductor fuse. The in-vehicle device according to claim 7.

12. A computer that performs opening / closing control of a plurality of opening / closing devices provided on a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided on the power supply line upstream of the opening / closing device in the current flow direction from the power supply device, Sets the cutoff characteristics of the semiconductor fuse according to the state or characteristics of the opening / closing device. Performs cutoff control of the semiconductor fuse or a process of transitioning a plurality of the opening / closing devices to the open state with the set cutoff characteristics. An information processing method for executing a process.

13. A computer that performs opening / closing control of a plurality of opening / closing devices provided on a power supply line from a power supply device mounted on a vehicle and a semiconductor fuse provided on the power supply line upstream of the opening / closing device in the current flow direction from the power supply device, Sets the cutoff characteristics of the semiconductor fuse according to the state or characteristics of the opening / closing device. Performs cutoff control of the semiconductor fuse or a process of transitioning a plurality of the opening / closing devices to the open state with the set cutoff characteristics. A program for causing processing to be executed.

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