On-board device, determination method, and computer program

Abstract

An on-board device according to one embodiment of the present disclosure comprises: an opening / closing device that is provided to a power line from a power supply device mounted on a vehicle; and a control unit that controls power of the opening / closing device, the power being output, by applying a voltage to the opening / closing device, to the downstream side in the flow direction of current from the power supply device. The control unit acquires a current value corresponding to the power output from the opening / closing device to the downstream side, and determines whether the opening / closing device is in a failure state on the basis of the application state of the voltage to the opening / closing device, the current value acquired from the opening / closing device, and an input current value according to the power supplied from the power supply device.

Description

In-vehicle device, determination method, and computer program

[0001] This application claims priority to Japanese Patent Application No. 2023-200166, filed November 27, 2023, and incorporates by reference all of the contents of that application.

[0002] A vehicle is equipped with a power supply control device (see, for example, Patent Document 1) that controls power supply from a battery to a load. In the power supply control device described in Patent Document 1, a semiconductor switch is provided in a current path of a current flowing from the battery to the load, and the power supply from the battery to the load is controlled by switching the semiconductor switch on or off.

[0003] A semiconductor switch has a control end. For example, if the semiconductor switch is a FET (Field Effect Transistor), the control end is a gate. The resistance value across the semiconductor switch varies depending on the voltage at the control end. By adjusting the voltage at the control end, the resistance value across the semiconductor switch is adjusted to a sufficiently small value, and the semiconductor switch is turned on. By adjusting the voltage at the control end, the resistance value across the semiconductor switch is adjusted to a sufficiently large value, and the semiconductor switch is turned off.

[0004] JP 2013-143905 A

[0005] An on-board device according to one embodiment of the present disclosure includes a switching device provided on a power line from a power supply device mounted on a vehicle, and a control unit that controls the output of power from the switching device to the downstream side in the direction of current flow from the power supply device by applying a voltage to the switching device, and the control unit acquires a current value corresponding to the power output from the switching device to the downstream side, and determines whether the switching device is in a faulty state based on the state of voltage application to the switching device, the current value acquired from the switching device, and the input current value of the power supplied from the power supply device.

[0006] Fig. 1 is a block diagram showing a configuration of a main part of a power supply system; Fig. 2 is a block diagram showing an example of the configuration of a microcomputer of an individual ECU; Fig. 3 is a block diagram showing an example of a connection between a microcomputer of an individual ECU and an IPD; Fig. 4 is a flowchart showing a procedure of a failure determination process; Fig. 5 is an explanatory diagram showing an example of a failure determination table; Fig. 6 is an explanatory diagram showing an example of a determination result table;

[0007] [Problem to be Solved by the Present Disclosure] However, in the power supply control device of Document 1, no consideration is given to efficiently determining the fault state of the switchgear.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to provide an in-vehicle device or the like that can efficiently determine a fault state of a switching device.

[0009] Effect of the Present Disclosure An in-vehicle device according to an embodiment of the present disclosure can efficiently determine a fault state of a switching device.

[0010] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. At least some of the embodiments described below may be combined in any combination.

[0011] (1) An on-board device according to one aspect of the present disclosure includes a switching device provided on a power line from a power supply device mounted on a vehicle, and a control unit that controls the output of power from the switching device to the downstream side in the direction of current flow from the power supply device by applying a voltage to the switching device, and the control unit acquires a current value corresponding to the power output from the switching device to the downstream side, and determines whether the switching device is in a fault state based on the state of voltage application to the switching device, the current value acquired from the switching device, and the input current value of the power supplied from the power supply device.

[0012] In this aspect, the switchgear is, for example, an intelligent power device (IPD). When a voltage is applied from the control unit, the switchgear outputs power supplied from an upstream power supply device to a load connected downstream. That is, the switchgear functions as a switch that switches the power output to the load based on the state of the voltage applied from the control unit. The switchgear and the control unit are connected via two control lines. One control line is a control line through which the control unit applies a voltage to the switchgear. The other control line is a control line through which the control unit obtains from the switchgear a current value corresponding to the power output from the switchgear to the downstream side. That is, a microcomputer (MCU) equipped with a control unit is connected to one switchgear via two pin terminals (PIN). The switchgear may experience a fault state, including an open fault state in which the switchgear does not output power to the downstream side despite being applied a high-level voltage by the control unit, or a short fault state in which the switchgear outputs power to the downstream side despite being applied a low-level voltage lower than the high-level voltage by the control unit. The control unit determines whether the switchgear is in a fault state based on whether a voltage is applied to the switchgear and the current value obtained from the switchgear. In addition, if the switching device is in a faulty state, the current detection terminal that detects the current value corresponding to the power output downstream may also be damaged, and the current value acquired by the control unit from the switching device may not match the current value of the power actually output by the switching device downstream. The control unit can determine whether the switching device is in a faulty state even if the current detection terminal of the switching device is damaged by determining whether the current value of the power supplied to the in-vehicle device (input current value) corresponds to the current value acquired from the switching device. Therefore, the control unit does not need to acquire the voltage value of the power output downstream by the switching device to determine whether the switching device is faulty, and the control line for acquiring the voltage value is not connected to a pin terminal of the microcontroller that includes the control unit. This reduces the number of pin terminals used to connect to one switching device in the microcontroller that includes the control unit, making it possible to connect multiple switching devices to the control unit.The control unit may obtain a voltage value converted from the current value transmitted by the switching device using a pull-down resistor, and determine whether the switching device is in a fault state based on the obtained voltage value.

[0013] (2) In one aspect of the in-vehicle device of the present disclosure, the control unit acquires the input current value from an upstream device located upstream of the power supply device, the opening / closing device and the upstream opening / closing device included in the upstream device are connected by the power line, and the input current value is the current value flowing through the power line.

[0014] In this aspect, the control unit of the in-vehicle device acquires an input current value from an upstream device provided upstream of the in-vehicle device. The in-vehicle device according to this aspect is, for example, an individual ECU (left zone ECU or right zone ECU), and the upstream device is, for example, an integrated ECU (front zone ECU). The upstream device includes a control unit, and the control unit of the upstream device and the control unit of the in-vehicle device can communicate via, for example, CAN or Ethernet. The control unit of the in-vehicle device acquires an input power value from the control unit of the upstream device and can determine whether the opening / closing device of the in-vehicle device is in a faulty state based on the input current value acquired from the control unit of the upstream device.

[0015] (3) An in-vehicle device according to one aspect of the present disclosure includes a plurality of the opening / closing devices, and the control unit determines that the opening / closing device is in a faulty state if the input current value does not match the sum of the current values ​​obtained from each of the plurality of opening / closing devices.

[0016] In this aspect, power supplied from an upstream device is distributed to multiple switching devices within the vehicle-mounted device and output from each switching device to a downstream load. When a switching device is not in a faulty state, the input current value matches the sum of the current values ​​acquired by the control unit of the vehicle-mounted device from each switching device. When a switching device is in a faulty state, the input current value may not match the sum of the current values ​​acquired by the control unit of the vehicle-mounted device from each switching device. The control unit of the vehicle-mounted device can determine whether a switching device is in a faulty state by determining whether the input current value matches the sum of the current values ​​acquired by the control unit of the vehicle-mounted device from each switching device.

[0017] (4) In one aspect of the in-vehicle device of the present disclosure, when no voltage is applied to the opening / closing device and the current value acquired from the opening / closing device is less than a predetermined threshold, the control unit determines whether the input current value matches the sum of the current values ​​acquired from each of the multiple opening / closing devices, and if they do not match, determines that the opening / closing device is in a short-circuit fault state.

[0018] In this aspect, the current detection terminal may enter a fixed-low state, in which it continues to detect a current value below a predetermined threshold even though the switching device is outputting power downstream. When the control unit of the in-vehicle device is not applying voltage to the switching device, if the current value acquired by the control unit from the switching device is below the predetermined threshold, two cases are possible: the switching device is in a normal state, or the switching device is in a short-circuit fault state and the current detection terminal is in a fixed-low state. In this case, the control unit of the in-vehicle device can determine whether the switching device is in a short-circuit fault state by determining whether the input current value matches the sum of the current values ​​acquired from each switching device. The state in which the control unit of the in-vehicle device is not applying voltage to the switching device includes a state in which the control unit of the in-vehicle device is applying a low-level voltage to the switching device.

[0019] (5) In one aspect of the in-vehicle device of the present disclosure, when a voltage is applied to the opening / closing device, if the current value acquired from the opening / closing device is equal to or greater than a predetermined threshold, the control unit determines whether the input current value matches the sum of the current values ​​acquired from each of the multiple opening / closing devices, and if they do not match, determines that the opening / closing device is in an open fault state.

[0020] In this aspect, the current detection terminal may enter a Hi-fixed state, in which it continues to detect a current value equal to or greater than a predetermined threshold even when the switching device is not outputting power downstream. When the control unit of the in-vehicle device applies a voltage to the switching device, if the current value acquired by the control unit from the switching device is equal to or greater than a predetermined threshold, two cases are possible: the switching device is in a normal state; or the switching device is in an open-circuit fault state and the current detection terminal is in a Hi-fixed state. In this case, the control unit of the in-vehicle device can determine whether the switching device is in an open-circuit fault state by determining whether the current value of the power supplied to the in-vehicle device matches the sum of the current values ​​acquired from each switching device. The state in which the control unit of the in-vehicle device applies a voltage to the switching device includes a state in which the control unit of the in-vehicle device applies a high-level voltage to the switching device.

[0021] (6) A determination method according to one aspect of the present disclosure acquires a current value corresponding to the power output downstream from a switching device installed on a power line from a power supply device mounted on a vehicle, and determines whether the switching device is in a fault state based on the voltage application state to the switching device, the current value acquired from the switching device, and the input current value of the power supplied from the power supply device.

[0022] In this aspect, by determining whether the current value (input current value) of the power supplied to the on-board device corresponds to the current value acquired from the switching device, it is possible to determine whether the switching device is in a fault state even if the current value detection terminal of the switching device is damaged. Therefore, the control unit does not need to acquire the voltage value of the power output from the switching device to the downstream side in order to determine whether the switching device is faulty, and the control line for acquiring the voltage value is not connected to the pin terminal of the microcomputer including the control unit. This reduces the number of pin terminals used to connect to one switching device in the microcomputer including the control unit, making it possible to connect a large number of switching devices to the control unit.

[0023] (7) A program according to one aspect of the present disclosure acquires a current value corresponding to the power output downstream from a switching device installed on a power line from a power supply device mounted on a vehicle, and causes a computer to execute a process of determining whether the switching device is in a fault state based on the voltage application state to the switching device, the current value acquired from the switching device, and the input current value of the power supplied from the power supply device.

[0024] In this aspect, by determining whether the current value (input current value) of the power supplied to the on-board device corresponds to the current value acquired from the switching device, it is possible to determine whether the switching device is in a fault state even if the current value detection terminal of the switching device is damaged. Therefore, the control unit does not need to acquire the voltage value of the power output from the switching device to the downstream side in order to determine whether the switching device is faulty, and the control line for acquiring the voltage value is not connected to the pin terminal of the microcomputer including the control unit. This reduces the number of pin terminals used to connect to one switching device in the microcomputer including the control unit, making it possible to connect a large number of switching devices to the control unit.

[0025] [Details of the embodiment of the present disclosure] Specific examples of a power supply control device according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0026] (Embodiment) FIG. 1 is a block diagram showing the main configuration of a power supply system S. In FIG. 1, power lines are indicated by solid lines, control lines are indicated by dashed lines, and communication lines are indicated by thick lines. The power supply system S is mounted on a vehicle M and includes a power supply device 1, an integrated ECU (Electronic Control Unit) 2, individual ECUs 3, and multiple loads 4. The power supply device 1 is a power supply that outputs direct current. The integrated ECU 2 corresponds to an upstream device and is connected to a positive terminal of the power supply device 1 and the individual ECUs 3. The individual ECUs 3 correspond to in-vehicle devices and are connected to the integrated ECU 2 and one end of the multiple loads 4. The negative terminal of the power supply device 1 and the other end of the load 4 are grounded. Note that the integrated ECU 2 may be a front zone ECU mounted in a front zone of the vehicle M, and the individual ECUs 3 may be a left zone ECU mounted in a left zone or a right zone ECU mounted in a right zone of the vehicle M. In the following description, in the current path from the power supply device 1 to the load 4, the power supply device 1 side is referred to as the upstream side of the current, and the load 4 side is referred to as the downstream side of the current.

[0027] The integrated ECU 2 includes a microcomputer 21 and an IPD (Intelligent Power Device) 22. The power supplied from the power supply device 1 is output to the downstream side via the IPD 22 of the integrated ECU 2. The IPD 22 corresponds to an upstream switching device. The microcomputer 21 controls the output of power to the downstream side of the IPD 22 and acquires the current value of the power output by the IPD 22 to the downstream side. The power output to the downstream side via the IPD 22 is supplied to the individual ECU 3.

[0028] The individual ECU 3 includes a microcomputer 31 and a plurality of IPDs 32. Power supplied from the power supply device 1 to the individual ECU 3 via the IPD 22 of the integrated ECU 2 is distributed to the plurality of IPDs 32 and output to a downstream load 4 via each IPD 32. The IPDs 32 correspond to switching devices. The microcomputer 31 controls the output of power downstream of the IPDs 32 and acquires a current value corresponding to the power output downstream by the IPDs 32.

[0029] The microcomputer 21 of the integrated ECU 2 and the microcomputer 31 of the individual ECU 3 are connected by a communication bus B and can communicate using a communication protocol such as CAN (Control Area Network), CAN-FD, or Ethernet (registered trademark). The microcomputer 21 of the integrated ECU 2 transmits to the microcomputer 31 of the individual ECU 3 the current value of the power output by the IPD 22 downstream, i.e., the current value (input current value) of the power supplied to the individual ECU 3. The IPD 22 (upstream switching device) and the IPD 32 (switching device) may be provided within a single ECU. In this case, the IPD 22 (upstream switching device) and the IPD 32 (switching device) may be controlled by the same microcomputer. The microcomputer 31 of the individual ECU 3 may control the output of power downstream of the IPD 22 of the integrated ECU 2 and may also acquire the current value of the power output downstream of the IPD 22.

[0030] 2 is a block diagram showing an example of the configuration of the microcomputer 31 of the individual ECU 3. The microcomputer 31 includes a control unit 311, a storage unit 312, an input / output I / F 313, and an in-vehicle communication unit 314. These are connected to an internal bus 315.

[0031] The control unit 311 has a processing element, such as a CPU (Central Processing Unit), that executes processing, and functions as a processing unit. The processing element of the control unit 311 reads and executes a computer program P stored in the storage unit 312, thereby executing processing to control the output of power to the downstream side of each IPD 32, processing to determine whether or not there is a failure in each IPD 32, and processing to record the results of the failure determination for each IPD 32. Note that the processing executed by the control unit 311 may be executed by an external device connected to the individual ECU 3 wirelessly or via a wire.

[0032] The storage unit 312 is a non-volatile memory. The storage unit 312 stores a computer program P, a fault determination table T1, and a determination result table T2. Details of the fault determination table T1 and the determination result table T2 will be described later. The computer program P may be provided to the microcomputer 31 using a non-transitory storage medium A on which the computer program P is readably recorded. The storage medium A may be, for example, a portable memory. If the storage medium A is a portable memory, the processing element of the control unit 311 may read the computer program P from the storage medium A using a reading device (not shown). The read computer program P is stored in the storage unit 312. Furthermore, the computer program P may be provided to the microcomputer 31 by a communication unit (not shown) of the microcomputer 31 communicating with an external device. The storage unit 312 also stores thresholds and coefficients (described later). The thresholds and coefficients stored in the storage unit 312 may be changed by reprogramming, for example, depending on the load 4 connected to the individual ECU 3 or the type of IPD 32 included in the individual ECU 3. Furthermore, the thresholds and coefficients stored in the storage unit 312 may be updated through communication with an external device.

[0033] The input / output I / F 313 is connected to the plurality of IPDs 32 via control lines. The input / output I / F 313 switches the voltage applied (output) to the IPDs 32 between a high-level voltage and a low-level voltage in accordance with an instruction from the control unit 311. A voltage value corresponding to the current value output by the IPDs 32 is input to the input / output I / F 313. The control unit 311 acquires the voltage value input to the input / output I / F 313.

[0034] The in-vehicle communication unit 314 is an input / output interface that uses a communication protocol such as CAN, CAN-FD, or Ethernet (registered trademark), and the control unit 311 communicates with the integrated ECU 2 or other in-vehicle devices via the in-vehicle communication unit 314. The in-vehicle communication unit 314 acquires, from the microcomputer 21 of the integrated ECU 2, the electric power output by the IPD 22 of the integrated ECU 2 to the downstream side, i.e., the current value (input current value) of the electric power supplied to the individual ECUs 3.

[0035] 3 is a block diagram showing an example of connection between the microcomputer 31 and the IPD 32 of the individual ECU 3. In FIG. 3, an example of connection between one IPD 32 and the microcomputer 31 is shown, and the other IPDs 32 are not shown. The input / output I / F 313 of the microcomputer 31 has a plurality of pin terminals (PIN(1), PIN(2), ... PIN(n)).

[0036] The IPD 32 includes a power receiving terminal 321, a power output terminal 322, a voltage application terminal 323, and a current value detection terminal 324. A power line connecting the IPD 22 of the integrated ECU 2 and the IPD 32 of the individual ECU 3 is connected to the power receiving terminal 321, and the power receiving terminal 321 receives power supplied from the upstream side.

[0037] The power output terminal 322 is connected to a power line that connects the IPD 32 and the load 4, and outputs the power received by the power receiving terminal 321 to the downstream load 4.

[0038] The voltage application terminal 323 is connected to the input / output I / F 313 of the microcomputer 31 via a control line. In this embodiment, the voltage application terminal 323 is connected to PIN (1) of the input / output I / F 313. The power output from the power output terminal 322 is controlled based on the state of voltage applied from the microcomputer 31 to the voltage application terminal 323. Specifically, the IPD 32 includes, for example, an N-channel field effect transistor (FET). The drain of the FET is connected to the power receiving terminal 321, and the source is the power output terminal 322. The gate of the FET is connected to the voltage application terminal 323, and the voltage applied to the voltage application terminal 323 is applied to the gate of the FET. As a result, when a high-level voltage is applied to the voltage application terminal 323, the power received by the power receiving terminal 321 (power supplied to the IPD 32) is output from the power output terminal 322 to the downstream load 4 via the FET. When a low-level voltage is applied to the voltage application terminal 323, no power is output from the power output terminal 322 to the downstream load 4. The switching device (IPD 32) may be configured by a P-channel FET, a mechanical relay, or the like.

[0039] The current detection terminal 324 is connected to the input / output I / F 313 of the microcomputer 31 via a control line. In this embodiment, the current detection terminal 324 is connected to PIN (2) of the input / output I / F 313. The current detection terminal 324 outputs to the microcomputer 31 a current value corresponding to the power output from the power output terminal 322. Specifically, the IPD 32 includes, for example, a current detection circuit. The current detection circuit is connected between the source of the FET and the power output terminal 322. The current detection terminal 324 is also connected to the current detection circuit and outputs to the microcomputer 31 a current value obtained by multiplying the current value of the power output from the power output terminal 322, detected by the current detection circuit, by a predetermined coefficient. A pull-down resistor R is connected between the power output terminal 322 and the microcomputer 31. This allows the microcomputer 31 to obtain a voltage value proportional to the current value output from the current detection terminal 324. That is, the microcomputer 31 can acquire a voltage value that is proportional to the current value (output current value) of the power output from the power output terminal 322 of the IPD 32 .

[0040] As described above, each of the other IPDs 32 included in the individual ECU 3 also includes a power receiving terminal 321, a power output terminal 322, a voltage application terminal 323, and a current value detection terminal 324. In addition, each IPD 32 is connected to two pin terminals (PIN) of the microcomputer 31.

[0041] 4 is a flowchart showing the procedure for the failure determination process. The control unit 311 of the individual ECU 3 acquires the state of voltage application to the IPD 32 (S1). The control unit 311 acquires the current value (output current value) of the power output from the power output terminal 322 of the IPD 32 from the IPD 32 being subjected to failure determination (S2). The control unit 311 also acquires the output current values ​​of other IPDs 32 that are not subjected to failure determination (S3). The control unit 311 acquires the output current value of the IPD 32 by calculating it based on the voltage value acquired at the pin terminal connected to the current value detection terminal of the IPD 32 in S2 and S3. The control unit 311 acquires the input current value for the individual ECU 3 from the microcomputer 21 of the integrated ECU 2 (S4).

[0042] The control unit 311 of the microcomputer 31 determines whether the voltage applied to the IPD 32 being subjected to fault detection is a high-level voltage (S5). If the voltage applied to the IPD 32 is a high-level voltage (S5: YES), the control unit 311 determines whether the output current value of the IPD 32 being subjected to fault detection is equal to or greater than a predetermined threshold (S6). The threshold in S6 is the current value of the interruption characteristic with the minimum current value among the interruption characteristics for loads expected to be connected to the IPD 32. Note that the control unit 311 may also determine whether the IPD 32 is outputting a current, i.e., whether the output current value is greater than 0 A or 0 A. If the output current value of the IPD 32 being subjected to fault detection is equal to or greater than the predetermined threshold (S6: YES), the control unit 311 determines whether the input current value to the IPD 32 matches the sum of the output current values ​​of all the IPDs 32 included in the individual ECUs 3 (S7). If the sum of the input current value and the output current value matches (S7: YES), the control unit 311 determines that the IPD 32 being subjected to fault detection is in a normal state (S8). If the output current value of the IPD 32 being subjected to fault detection is not equal to or greater than a predetermined threshold (is less than the threshold) (S6: NO), or if the sum of the input current value and the output current value does not match (S7: NO), the control unit 311 determines that the IPD 32 being subjected to fault detection is in an open circuit fault state (S9). Note that if the control unit 311 determines that the IPD 32 is in an open circuit fault state, the control unit 311 may, for example, stop control of the IPD 32 determined to be in an open circuit fault state.

[0043] If the voltage applied to the IPD 32 is not a high-level voltage (i.e., a low-level voltage) (S5: NO), the control unit 311 determines whether the output current value of the IPD 32 being subjected to fault detection is equal to or greater than a predetermined threshold (S10). The threshold in S10 is the current value of the interruption characteristic with the minimum current value among the interruption characteristics for the loads expected to be connected to the IPD 32. Note that the control unit 311 may also determine whether the IPD 32 is outputting a current, i.e., whether the output current value is greater than 0 A or 0 A. If the output current value of the IPD 32 being subjected to fault detection is not equal to or greater than the predetermined threshold (i.e., less than the threshold) (S10: NO), the control unit 311 determines whether the input current value to the IPD 32 matches the sum of the output current values ​​of all the IPDs 32 included in the individual ECU 3 (S11). If the input current value and the sum of the output current values ​​match (S11: YES), the control unit 311 determines that the IPD 32 being subjected to fault detection is in a normal state (S12). If the output current value of the IPD 32 to be subjected to fault determination is equal to or greater than a predetermined threshold value (S10: YES), or if the sum of the input current value and the output current value does not match (S11: NO), the control unit 311 determines that the IPD 32 to be subjected to fault determination is in a short-circuit fault state (S13). Note that, if it is determined that the IPD 32 is in a short-circuit fault state, the control unit 311 may, for example, send a signal to the microcomputer 21 of the integrated ECU 2 requesting that power supply to the individual ECUs 3 be stopped.

[0044] After determining the state of the IPD 32 in S8, S9, S12, or S13, the control unit 311 stores the determination result in a determination result table (S14), and ends the process.

[0045] 5 is an explanatory diagram showing an example of the failure determination table T1. The control unit 311 of the individual ECU 3 may determine the state of the IPD 32 by referring to the failure determination table T1. The management items (fields) of the failure determination table T1 include, for example, a condition field including a voltage application field, an output current value field, and an input current value field, and a state field including an IPD state field and a current value detection terminal state field.

[0046] Each field of the condition field stores a condition for determining the state of the IPD 32. The voltage application field stores the state of voltage application from the microcomputer 31 to the IPD 32. When a low-level voltage is applied to the IPD 32, "L" is stored in the voltage application field. When a high-level voltage is applied to the IPD 32, "H" is stored in the voltage application field.

[0047] The output current value field stores the condition for the threshold value of the output current value of the IPD 32 acquired by the control unit 311. When the condition indicates that the output current value is less than the threshold value, "L" is stored in the output current value field. When the condition indicates that the output current value is equal to or greater than the threshold value, "H" is stored in the output current value field.

[0048] The input current value field stores a condition as to whether the input current value acquired by the control unit 311 from the microcomputer 21 of the integrated ECU 2 matches the sum of the output current values ​​of all the IPDs 32 provided in the individual ECUs 3. When the condition indicates that the input current value matches the sum of the output current values, the input current value field stores "match." When the condition indicates that the input current value does not match the sum of the output current values, the input current value field stores "mismatch." Note that when it does not matter whether the input current value matches the output current value, a null value is stored in the input current value field.

[0049] Each field of the status field stores the status of the IPD 32 or the current value detection terminal determined by the control unit 311 for the condition stored in the condition field. The IPD status field stores the status of the IPD 32 determined by the control unit 311 for the condition. The current value detection terminal status field stores the status of the current value detection terminal of the IPD 32 determined by the control unit 311 for the condition.

[0050] When a low-level voltage is applied to the IPD 32, if the output current value is less than the threshold and the sum of the input current value and the output current value matches, the IPD 32 and the current value detection terminal 324 are determined to be in a normal state. When a low-level voltage is applied to the IPD 32, if the output current value is equal to or greater than the threshold, the IPD 32 is determined to be in a short-circuit fault state, and the current value detection terminal 324 is determined to be in a normal state or a fixed-at-Hi state. When a low-level voltage is applied to the IPD 32, if the output current value is less than the threshold and the sum of the input current value and the output current value does not match, the IPD 32 is determined to be in a short-circuit fault state, and the current value detection terminal 324 is determined to be in a fixed-at-Lo state.

[0051] When a high-level voltage is applied to the IPD 32, if the output current value is equal to or greater than the threshold and the sum of the input current value and the output current value matches, the IPD 32 and the current value detection terminal 324 are determined to be in a normal state. When a high-level voltage is applied to the IPD 32, if the output current value is less than the threshold, the IPD 32 is determined to be in an open fault state, and the current value detection terminal 324 is determined to be in a normal state or a fixed-at-Lo state. When a high-level voltage is applied to the IPD 32, if the output current value is equal to or greater than the threshold and the sum of the input current value and the output current value does not match, the IPD 32 is determined to be in an open fault state, and the current value detection terminal 324 is determined to be in a fixed-at-Hi state.

[0052] 6 is an explanatory diagram showing an example of the judgment result table T2. The judgment result table T2 stores the time when the control unit 311 made a judgment, information identifying the IPD 32 whose state was judged, and the judgment result, all associated with each other. The management items of the judgment result table include, for example, a judgment time field, a judgment IPD field, and a judgment result field.

[0053] The determination time field stores the time when the control unit 311 of the microcomputer 31 determined the state of the IPDs 32, with the time when the vehicle M started and the microcomputer 31 started controlling each IPD 32 as a reference (time 0). The control unit 311 determines the state of the multiple IPDs 32 included in the individual ECU 3 in a cycle of, for example, 5 milliseconds. Note that the cycle in which the control unit 311 makes the determination is not limited to 5 milliseconds and may be, for example, 10 milliseconds.

[0054] The determination IPD field stores information identifying the IPD 32 whose state has been determined (the IPD 32 that has been subjected to the failure determination). In this embodiment, the multiple IPDs 32 included in the individual ECU 3 are assigned codes (IPD 32(a), IPD 32(b), IPD 32(c), ...) for identifying each IPD 32. The determination IPD field stores the code of the IPD 32 whose state has been determined. After determining the states of all the IPDs 32, the control unit 311 repeatedly determines the states of all the IPDs 32 again, starting with IPD 32(a). The control unit 311 outputs the determination results of each IPD 32 in turn at a predetermined cycle, and stores the output determination result in a new record in the determination result table T2 each time.

[0055] The determination result field stores the determination result of the state of the IPD 32 (either "normal," "short circuit failure," or "open circuit failure") made by the control unit 311. The determination result table T2 may also include a current value detection terminal state determination result field, in which the state of the current value detection terminal 324 of the IPD 32 determined by the control unit 311 is stored.

[0056] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The technical features described in each embodiment may be combined with one another, and the scope of the present invention is intended to include all modifications within the scope of the claims and equivalents thereto. Furthermore, independent and dependent claims described in the claims may be combined with one another in any and all combinations, regardless of the reference format. Furthermore, while the claims use a format in which a claim references two or more other claims (multiple claim format), this is not limiting. Multiple claims (multiple multiple claims) that reference at least one other claim may also be used.

[0057] REFERENCE SIGNS LIST 1 Power supply device 2 Integrated ECU 21 Microcomputer 22 IPD 3 Individual ECU 31 Microcomputer 311 Control unit 312 Storage unit 313 Input / output I / F 314 In-vehicle communication unit 32 IPD 321 Power receiving terminal 322 Power output terminal 323 Voltage application terminal 324 Current value detection terminal 4 Load A Storage medium M Vehicle P Computer program S Power supply system T1 Failure determination table T2 Determination result table

Claims

1. An on-vehicle device comprising: a switching device provided on a power line from a power supply device mounted on a vehicle; and a control unit that controls the output of power from the switching device to the downstream side in the direction of current flow from the power supply device by applying a voltage to the switching device, wherein the control unit obtains a current value corresponding to the power output from the switching device to the downstream side, and determines whether or not the switching device is in a faulty state based on the state of voltage application to the switching device, the current value obtained from the switching device, and the input current value of the power supplied from the power supply device.

2. The vehicle-mounted device according to claim 1, wherein the control unit acquires the input current value from an upstream device arranged upstream on the side of the power supply device, the opening / closing device and an upstream opening / closing device included in the upstream device are connected by the power line, and the input current value is a current value flowing in the power line.

3. An in-vehicle device as described in claim 1 or 2, comprising a plurality of said opening / closing devices, and wherein the control unit determines that the opening / closing device is in a faulty state if the input current value does not match the sum of the current values ​​acquired from each of the plurality of said opening / closing devices.

4. The in-vehicle device according to claim 3, wherein the control unit, when no voltage is applied to the switching device and the current value acquired from the switching device is less than a predetermined threshold value, determines whether the input current value matches the sum of the current values ​​acquired from each of the multiple switching devices, and if they do not match, determines that the switching device is in a short-circuit fault state.

5. The in-vehicle device according to claim 3, wherein the control unit, when applying a voltage to the switching device, determines whether the input current value matches the sum of the current values ​​acquired from each of the multiple switching devices when the current value acquired from the switching device is equal to or greater than a predetermined threshold value, and, if they do not match, determines that the switching device is in an open fault state.

6. A method for determining whether or not a switching device is in a fault state, the method comprising: acquiring a current value corresponding to the power output downstream from a switching device provided on a power line extending from a power supply device mounted on a vehicle; and determining whether or not the switching device is in a fault state based on the voltage applied to the switching device, the current value acquired from the switching device, and the input current value of the power supplied from the power supply device.

7. A computer program that causes a computer to execute a process of acquiring a current value corresponding to the power output downstream from a switching device installed in a power line from a power supply device mounted on a vehicle, and determining whether or not the switching device is in a fault state based on the voltage application state to the switching device, the current value acquired from the switching device, and the input current value of the power supplied from the power supply device.

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