On-vehicle device

Abstract

To efficiently determine a failure state of a switching device.SOLUTION: An on-vehicle device includes: a plurality of opening / closing devices provided in parallel on a power line from a power supply device mounted on a vehicle; a control unit that applies voltage to each of the opening / closing devices to control output of electric power of each of the opening / closing devices to a downstream side in a flow direction of current from the power supply device; a first determination circuit that is provided in each of the opening / closing devices and outputs a first determination result indicating whether or not an application state of the voltage to the opening / closing device by the control unit and an output state of the electric power to the downstream side by the opening / closing device correspond to each other; and a second determination circuit that outputs a second determination result obtained by determining whether or not all the first determination results output by each of the plurality of first determination circuits indicate correspondence, where the control unit acquires the second determination result from the second determination circuit and determines whether or not there is the opening / closing device in a failure state among the plurality of opening / closing devices based on the acquired second determination result.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present technology relates to an in-vehicle device. [Background technology]

[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] The semiconductor switch has a control end. For example, when the semiconductor switch is a FET (Field Effect Transistor), the control end is a gate. The resistance value between both ends of the semiconductor switch changes according to the voltage at the control end. By adjusting the voltage at the control end, the resistance value between both ends of the semiconductor switch is adjusted to a sufficiently small value, and the semiconductor switch is switched on. By adjusting the voltage at the control end, the resistance value between both ends of the semiconductor switch is adjusted to a sufficiently large value, and the semiconductor switch is switched off. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-143905 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the power supply control device of Document 1, no consideration is given to efficiently determining the fault state of the switchgear.

[0006] The present disclosure has been made in consideration of the above circumstances, and has an object to provide an in-vehicle device or the like that can efficiently determine a fault state of a switching device. [Means for solving the problem]

[0007] An in-vehicle device according to one embodiment of the present disclosure includes a plurality of opening / closing devices arranged in parallel on a power line from a power supply device mounted on a vehicle, a control unit that controls the output of power from each of the opening / closing devices to the downstream side in the direction of current flow from the power supply device by applying a voltage to each of the opening / closing devices, a first judgment circuit that is provided in each of the opening / closing devices and outputs a first judgment result indicating whether or not a state of voltage application by the control unit to the opening / closing device corresponds to a state of power output by the opening / closing device to the downstream side, and a second judgment circuit that outputs a second judgment result that determines whether or not all of the first judgment results output by each of the plurality of first judgment circuits indicate a correspondence, and the control unit acquires the second judgment result from the second judgment circuit and determines whether or not any of the plurality of opening / closing devices is in a faulty state based on the acquired second judgment result. Effect of the Invention

[0008] An in-vehicle device according to an embodiment of the present disclosure can efficiently determine a fault state of the opening and closing device. [Brief description of the drawings]

[0009] [Figure 1] 1 is a block diagram showing a configuration of a main part of an in-vehicle device according to a first embodiment. [Diagram 2] 2 is a block diagram showing an example of the configuration of a microcomputer of an in-vehicle device according to the first embodiment. FIG. [Diagram 3] 10 is a timing chart showing the input and output of the first judgment circuit according to the second embodiment. FIG. [Figure 4] 10 is a flowchart showing the procedure of a failure determination process according to the second embodiment. [Diagram 5] FIG. 11 is a block diagram showing a configuration of a main part of an in-vehicle device according to a third embodiment. [Figure 6] FIG. 11 is a timing chart showing the input and output of the first judgment circuit according to the third embodiment. [Figure 7]FIG. 11 is a block diagram showing a configuration of a main part of an in-vehicle device according to a fourth embodiment. [Figure 8] FIG. 11 is a timing chart showing the input and output of the first decision circuit according to the fourth embodiment. [Figure 9] FIG. 11 is a block diagram showing a configuration of a main part of a power supply system according to a fifth embodiment. [Figure 10] 13 is a block diagram showing an example of connection between a microcomputer and an IPD in an in-vehicle device according to a fifth embodiment. FIG. [Figure 11] 13 is a flowchart showing the procedure of a failure determination process according to the fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] (1) An in-vehicle device according to one embodiment of the present disclosure includes a plurality of opening / closing devices arranged in parallel on a power line from a power supply device mounted on a vehicle; a control unit that controls the output of power from each of the opening / closing devices to a downstream side in the direction of current flow from the power supply device by applying a voltage to each of the opening / closing devices; a first judgment circuit that is provided in each of the opening / closing devices and outputs a first judgment result indicating whether or not a state of voltage application by the control unit to the opening / closing device corresponds to a state of power output by the opening / closing device to the downstream side; and a second judgment circuit that outputs a second judgment result that determines whether or not all of the first judgment results output by each of the plurality of first judgment circuits indicate a correspondence, and the control unit acquires the second judgment result from the second judgment circuit and determines whether or not any of the plurality of opening / closing devices is in a faulty state based on the acquired second judgment result.

[0012] In this embodiment, the switching device is, for example, an IPD (Intelligent Power Device), and when a voltage is applied from the control unit, the switching device outputs power supplied from an upstream power supply device to a load connected downstream. That is, the switching device functions as a switch that switches the power output to the load based on the application state of the voltage from the control unit. The switching device may be in a fault state including an open fault state in which the switching device does not output power to the downstream side despite the application of a high-level voltage from the control unit, or a short fault state in which the switching device outputs power to the downstream side despite the application of a low-level voltage lower than the high-level voltage from the control unit. The first determination circuit is provided for each of the multiple switching devices provided in the vehicle-mounted device, and determines whether or not the application state of the voltage from the control unit to each switching device corresponds (matches) with the output state of power to the downstream side by each switching device, and outputs the determination result (first determination result) to the second determination circuit. The first determination result is input to the second determination circuit from each of the multiple first determination circuits. The second judgment circuit judges whether all the first judgment results input from each of the multiple first judgment circuits indicate that the state of voltage application from the control unit to each switching device corresponds to the state of power output from each switching device to the downstream side, and outputs the judgment result (second judgment result) to the control unit. That is, when all the switching devices in which the first judgment circuits connected to the second judgment circuit are provided are not in a fault state, the second judgment result is output, which indicates that all the first judgment results indicate that they correspond. When at least one of the multiple switching devices in which the first judgment circuits connected to the second judgment circuit are provided is in a fault state, the second judgment result is output, which indicates that at least one of the first judgment results indicates that they do not correspond. When the second judgment result acquired from the second judgment circuit is one in which it is determined that all the first judgment results indicate that they correspond, the control unit is able to judge that all the switching devices in which the first judgment circuits connected to the second judgment circuit are provided are not in a fault state.Furthermore, when the second judgment result acquired from the second judgment circuit indicates that at least one of the first judgment results is not compatible, the control unit can determine that one of the multiple switching devices provided with the first judgment circuit connected to the second judgment circuit is in a fault state. Since the control unit can determine the presence or absence of a switching device in a fault state based only on the second judgment result, the control unit can efficiently determine the fault state of the switching device. In other words, it is not necessary for a microcomputer having a control unit to have pin terminals (PINs) corresponding to each of the multiple first judgment circuits, and by using pin terminals to which the second judgment result from the second judgment circuit is input, an increase in the number of terminals (pins) required in a microcomputer or the like can be suppressed.

[0013] (2) In an in-vehicle device according to one embodiment of the present disclosure, the first judgment circuit is connected to a control line connecting the control unit and the switching device and a power line connecting the switching device and a downstream load, and obtains the voltage application state from the control line and the power output state from the power line.

[0014] In this aspect, the control unit is connected to the switchgear via one pin terminal and a control line, and the control unit applies a voltage to the switchgear via the control line. The switchgear is connected to a load via a power line. The switchgear outputs power supplied from an upstream power supply device to a downstream load. The first determination circuit is connected to a control line connecting the control unit and the switchgear, and is capable of acquiring an application state indicating whether the control unit is applying a low level voltage or a high level voltage to the switchgear. The first determination circuit is also connected to a power line connecting the switchgear and the load, and is capable of acquiring an output state of power indicating whether the voltage value of the power output by the switchgear is higher than a predetermined threshold value or not. As described above, the control unit is connected to one switchgear via one pin terminal (PIN). Also, one second determination circuit is provided for a plurality of switchgears, and the control unit is connected to the second determination circuit via one pin terminal. Since the first control circuit acquires the output state of power from the power line, the control unit does not need to acquire the power output state of all the switchgears, and the control line for acquiring the power output state is not connected to a pin terminal of a microcomputer having the control unit. This reduces the number of pin terminals used to connect to one switching device in a microcomputer having a control unit, making it possible to connect a large number of switching devices to the control unit.

[0015] (3) In an in-vehicle device according to one embodiment of the present disclosure, the first determination circuit outputs a low-level voltage indicating that the voltage application state and the power output state correspond to each other when, when the control unit applies a high-level voltage to the opening / closing device, the voltage value of the power output by the opening / closing device to the downstream side is higher than a predetermined threshold, or when, when the control unit applies a low-level voltage to the opening / closing device, the voltage value of the power output by the opening / closing device to the downstream side is equal to or lower than a predetermined threshold, and outputs a high-level voltage indicating that the voltage application state and the power output state do not correspond to each other when, when the control unit applies a high-level voltage to the opening / closing device, the voltage value of the power output by the opening / closing device to the downstream side is equal to or lower than a predetermined threshold, or when the control unit applies a low-level voltage to the opening / closing device, the voltage value of the power output by the opening / closing device to the downstream side is higher than the predetermined threshold.

[0016] In this embodiment, the first judgment circuit is configured with an exclusive OR circuit (XOR circuit), and outputs a low-level voltage as the first judgment result when the voltage level applied by the control unit to the switchgear matches the voltage level of the power output by the switchgear to the downstream side relative to the threshold. Also, when the voltage level applied by the control unit to the switchgear does not match the voltage level of the power output by the switchgear to the downstream side relative to the threshold, the first judgment circuit outputs a high-level voltage as the first judgment result. This makes it possible for the first judgment circuit to output a high-level voltage as the first judgment result indicating that the voltage application state and the power output state do not correspond when the switchgear is in a fault state.

[0017] (4) In an in-vehicle device according to one embodiment of the present disclosure, the second judgment circuit acquires each of the voltages output by the multiple first judgment circuits, and if all of the voltages acquired from each of the first judgment circuits are low-level voltages, outputs a low-level voltage to the control unit, and if at least one of the voltages acquired from each of the first judgment circuits is a high-level voltage, outputs a high-level voltage to the control unit.

[0018] In this embodiment, the second judgment circuit is configured by a logical sum circuit (OR circuit), and when all of the voltages (first judgment results) acquired from the respective first judgment circuits are low-level voltages, the second judgment circuit outputs a low-level voltage (a signal indicating that all of the first judgment results correspond) to the control unit as the second judgment result. Also, when at least one of the voltages (first judgment results) acquired from the respective first judgment circuits is a high-level voltage, the second judgment circuit outputs a high-level voltage (a signal indicating that at least one of the first judgment results does not correspond) to the control unit as the second judgment result. This allows the second judgment circuit to output a high-level voltage to the control unit when at least one of the switching devices in which the first judgment circuits connected to the second judgment circuit are provided is in a fault state.

[0019] (5) In an in-vehicle device according to one embodiment of the present disclosure, when a high-level voltage is input from the second judgment circuit, the control unit determines that at least one of the multiple opening and closing devices is in a fault state.

[0020] In this aspect, the second judgment circuit outputs a high-level voltage to the control unit as the second judgment result when at least one of the switching devices in which the first judgment circuit connected to the second judgment circuit is provided is in a fault state. Therefore, the control unit can judge the presence or absence of a switching device in a fault state based only on the second judgment result acquired from the second judgment circuit.

[0021] (6) In an in-vehicle device according to one embodiment of the present disclosure, the control unit acquires the voltage output by the second judgment circuit at a predetermined period, and if the voltage acquired from the second judgment circuit is a high-level voltage a predetermined number of times or more in succession, determines that at least one of the multiple opening and closing devices is in a fault state.

[0022] In this embodiment, after the control unit applies a high-level voltage to the switching device, the switching device outputs power to the downstream side, so that a time difference (turn-on delay time or turn-off delay time) occurs between the time when the first determination circuit acquires the voltage application state and the time when it acquires the power output state due to the switching characteristics of the switching device. Even when the switching device is in a normal state, the application state and the output state do not match during the period from when the first determination circuit acquires the voltage application state to when it acquires the power output state, so the first control circuit outputs a high-level voltage. Accordingly, the second determination circuit also outputs a high-level voltage for the time difference, so that the control unit may acquire a high-level voltage from the second determination circuit even when there is no switching device in a faulty state. Note that when there is no switching device in a faulty state, the time during which the high-level voltage is output from the second determination circuit is very short. Therefore, the control unit periodically acquires the voltage output by the second judgment circuit at a predetermined time interval, and when the acquired voltage is a high-level voltage a predetermined number of times in succession, i.e., when a high-level voltage is output from the second judgment circuit for a predetermined period of time or more, it judges that at least one of the switching devices in which the first judgment circuit connected to the second judgment circuit is provided is in a faulty state. This makes it possible for the control unit to prevent or reduce erroneous judgments that a switching device is in a faulty state when there is no switching device in a faulty state.

[0023] (7) An in-vehicle device according to an aspect of the present disclosure includes a time constant increasing circuit that increases a time constant of an input of a voltage application state to the first determination circuit.

[0024] In this embodiment, after the control unit applies a high-level voltage to the switching device, the switching device outputs power to the downstream side, so there is a time difference between the time when the first determination circuit acquires the voltage application state and the time when it acquires the power output state. Even when the switching device is in a normal state, the application state and the output state do not match during the period from when the first determination circuit acquires the voltage application state to when it acquires the power output state, so the first control circuit outputs a high-level voltage. By providing an RC filter (time constant increase circuit) composed of, for example, a resistor and a capacitor between the control line for the control unit to apply a voltage to the switching device and the first determination circuit, it is possible to increase the time constant of the signal of the voltage application state input to the first determination circuit. This makes the rise or fall of the signal of the voltage application state input to the first determination circuit slow, and the time for the first control circuit to output a high-level voltage is shortened. Therefore, it is possible to prevent or reduce erroneous determinations in which the control unit determines that there is a switching device in a faulty state when there is no switching device in a faulty state. The time constant increase circuit may be, for example, a coil.

[0025] (8) An in-vehicle device according to an aspect of the present disclosure includes a time constant increasing circuit that increases a time constant of an output of the first determination result from the first determination circuit.

[0026] In this embodiment, after the control unit applies a high-level voltage to the switching device, the switching device outputs power to the downstream side, so there is a time difference between the time when the first determination circuit acquires the voltage application state and the time when it acquires the power output state. Even when the switching device is in a normal state, the application state and the output state do not match during the period from when the first determination circuit acquires the voltage application state to when it acquires the power output state, so the first control circuit outputs a high-level voltage. By providing an RC filter (time constant increase circuit) composed of, for example, a resistor and a capacitor between the first determination circuit and the second determination circuit, the rise or fall of the signal (voltage) indicating the first determination result output by the first control circuit and input to the second determination circuit becomes slow (response is low), and the time during which the high-level voltage is input to the second determination circuit becomes short. Therefore, it is possible to prevent or reduce erroneous determinations in which the control unit determines that a switching device in a faulty state exists when there is no switching device in a faulty state. The time constant increase circuit may be, for example, a coil.

[0027] (9) In the in-vehicle device according to one aspect of the present disclosure, the first determination circuit is configured with an exclusive OR circuit, and the second determination circuit is configured with a logical OR circuit.

[0028] In this embodiment, the first judgment circuit is configured by an exclusive OR circuit (XOR circuit), and the second judgment circuit is configured by an OR circuit (OR circuit). This makes it possible to determine the presence or absence of a faulty switching device with a cheaper configuration than when the presence or absence of a faulty switching device is determined only by software processing. The first judgment circuit and the second judgment circuit may be configured as an integrated circuit, or may be configured in an integrated circuit (hardware processing unit) such as an FPGA (Field Programmable Gate Array) or an ASIC (application specific integrated circuit).

[0029] (10) In an in-vehicle device according to one embodiment of the present disclosure, the control unit acquires the second judgment result, and determines whether or not at least one of the multiple opening / closing devices is in a faulty state based on the second judgment result. If it is determined that at least one of the opening / closing devices is in a faulty state, the control unit acquires a current value corresponding to the power output from the opening / closing device downstream, and determines whether or not the opening / closing device is in a faulty state based on the voltage application state to the opening / closing device, the current value acquired from the opening / closing device, and the input current value of the power supplied from the power supply device.

[0030] In this aspect, when the control unit determines that at least one of the switching devices provided with the first determination circuit connected to the second determination circuit is in a fault state, the control unit determines whether each switching device is in a fault state based on the voltage application state to each switching device and the current value corresponding to the power output by each switching device. When the switching device is in a fault state, the current value detection terminal for detecting the current value corresponding to the power output to the downstream side 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 to the downstream side. The control unit can determine whether the switching device is in a fault state even when the current value detection terminal of the switching device is damaged by determining whether the current value (input current value) of the power supplied to the vehicle-mounted device corresponds to the current value acquired from the switching device. This allows the control unit to identify the switching device in a fault state. The control unit may obtain a voltage value converted from the current value transmitted by the switching device by a pull-down resistor, and determine whether the switching device is in a fault state based on the obtained voltage value.

[0031] [Details of the embodiment of the present disclosure] Specific examples of power supply control devices according to embodiments of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is intended to include all modifications within the scope of the claims and the meaning equivalent to the claims.

[0032] (Embodiment 1) FIG. 1 is a block diagram showing a main configuration of an in-vehicle device 3 according to the first embodiment. In FIG. 1, power lines are indicated by solid lines, and control lines are indicated by dashed lines. The in-vehicle device 3 is, for example, an individual ECU (Electronic Control Unit) mounted on a vehicle M. The in-vehicle device 3 may be a left zone ECU mounted on a left zone of the vehicle M or a right zone ECU mounted on a right zone of the vehicle M. The in-vehicle device 3 is connected to a positive electrode of a power supply device 1 and one end of a load 4. The negative electrode of the power supply device 1 and the other end of the load 4 are grounded. 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.

[0033] The in-vehicle device 3 includes a microcomputer 31, a plurality of IPDs (Intelligent Power Devices) 32, a first determination circuit 33 equal in number to the number of the IPDs 32, and a second determination circuit 34. The in-vehicle device 3 may include a plurality of second determination circuits. The IPDs 32 correspond to an opening and closing device, and the microcomputer 31 controls the output of power to the downstream side of the IPDs 32 by applying a high-level voltage or a low-level voltage lower than the high-level voltage, and obtains a second determination result from the second determination circuit. Details of the second determination result will be described later.

[0034] In this embodiment, the in-vehicle device 3 includes three IPDs 32, IPDs 32a to 32c, but the number of IPDs 32 included in the in-vehicle device 3 may be two or four or more. The IPDs 32 receive power supplied from the power supply device 1 and control the power output to the load 4 based on the voltage application state from the microcomputer 31. Specifically, the IPDs 32 include, for example, an N-channel type FET (Field Effect Transistor). The drain of the FET is connected to the power supply device 1, and the source is connected to the load 4. The gate of the FET is connected to the microcomputer 31, and the voltage applied to the IPDs 32 is applied to the gate of the FET. As a result, when a high-level voltage is applied to the IPDs 32, the IPDs 32 output power to the downstream load 4. Also, when a low-level voltage is applied to the IPDs 32, the IPDs 32 do not output power to the downstream load 4. The opening and closing device (IPDs 32) may be configured by a P-channel type FET or a mechanical relay, etc.

[0035] The in-vehicle device 3 includes three first determination circuits, ie, first determination circuits 33a to 33c. One first determination circuit 33 is provided for each IPD 32. The first determination circuit 33 is connected to a control line connecting the microcomputer 31 and the IPD 32, and a power line connecting the IPD 32 and the load 4. The first determination circuit acquires a voltage application state indicating whether the microcomputer 31 applies a high-level voltage or a low-level voltage to the IPD 32 from the control line connecting the microcomputer 31 and the IPD 32. In addition, the first control circuit acquires a power output state indicating whether a voltage value of the power output by the IPD 32 to the load 4 is higher than a predetermined threshold value from the power line connecting the IPD 32 and the load 4.

[0036] The first determination circuit outputs a high-level voltage or a low-level voltage to the second determination circuit 34 as a first determination result indicating whether the acquired voltage application state and power output state correspond to each other. Specifically, when the microcomputer 31 applies a high-level voltage to the IPD 32 and the voltage value of the power output by the IPD 32 to the downstream side is higher than a predetermined threshold, or when the microcomputer 31 applies a low-level voltage to the IPD 32 and the voltage value of the power output by the IPD 32 to the downstream side is equal to or lower than a predetermined threshold, the first determination circuit 33 outputs a low-level voltage indicating that the voltage application state and power output state correspond to each other. When the microcomputer 31 applies a high-level voltage to the IPD 32 and the voltage value of the power output from the IPD 32 to the downstream side is equal to or lower than a predetermined threshold, or when the microcomputer 31 applies a low-level voltage to the IPD 32 and the voltage value of the power output from the IPD 32 to the downstream side is higher than a predetermined threshold, the first determination circuit 33 outputs a high-level voltage indicating that the voltage application state and the power output state do not correspond. That is, the first determination circuit is configured of an exclusive OR (XOR circuit).

[0037] In this embodiment, the in-vehicle device 3 includes the same number of first determination circuits 33 as the IPDs 32, but the number of first determination circuits 33 may be different from the number of IPDs 32. That is, there may be an IPD 32 that does not include a first determination circuit 33.

[0038] The second judgment circuit 34 acquires the first judgment results from each of the multiple first judgment circuits 33a to 33c. The second judgment circuit 34 may acquire the first judgment results from two or four or more first judgment circuits 33. In the present embodiment, the in-vehicle device 3 includes one second judgment circuit 34, and all the first judgment circuits 33 included in the in-vehicle device 3 are connected to the single second judgment circuit 34, but this is not limited thereto. The in-vehicle device 3 may include multiple second judgment circuits 34, and each of the multiple first judgment circuits 33 may be connected to one of the second judgment circuits 34.

[0039] The second judgment circuit 34 outputs to the microcomputer 31 a second judgment result indicating whether or not all the first judgment results indicate that the voltage application state and the power output state of the IPD 32 correspond to each other based on the first judgment results acquired from the first judgment circuits 33a to 33c. Specifically, when a low-level voltage is output from all the first judgment circuits 33a to 33c connected to the second judgment circuit 34, the second judgment circuit 34 outputs a low-level voltage. When a high-level voltage is output from at least one of the first judgment circuits 33a to 33c, the second judgment circuit 34 outputs a high-level voltage. That is, the second judgment circuit 34 is configured by a logical sum circuit (OR circuit). As a result, when all the first judgment results acquired by the second judgment circuit 34 indicate that the voltage application state and the power output state of the IPD 32 correspond to each other, the second judgment circuit 34 outputs a low-level voltage indicating that all the first judgment results indicate that the application state and the output state correspond to each other. Furthermore, when at least one of the first judgment results acquired by the second judgment circuit 34 indicates that the voltage application state and the power output state of the IPD 32 do not correspond, the second judgment circuit 34 outputs a high-level voltage indicating that the at least one first judgment result indicates that the application state and the output state do not correspond.

[0040] 2 is a block diagram showing an example of the configuration of the microcomputer 31 of the in-vehicle device 3 according to the embodiment 1. The microcomputer 31 includes a control unit 311, a storage unit 312, and an input / output I / F 313. These are connected to an internal bus 315.

[0041] 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 executes processing for controlling the output of power to the downstream side of each IPD 32 and processing for determining whether or not there is an IPD 32 in a faulty state, by reading and executing a computer program P stored in the storage unit 312. Note that the processing executed by the control unit 311 may be executed by an external device connected to the in-vehicle device 3 wirelessly or via a wire.

[0042] The storage unit 312 is a non-volatile memory. The storage unit 312 stores a computer program P 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 is, for example, a portable memory. When 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, which will be 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 in-vehicle device 3 or the type of the IPD 32 provided in the in-vehicle device 3. The thresholds and coefficients stored in the storage unit 312 may be updated by communication with an external device.

[0043] The input / output I / F 313 is connected to the multiple 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 or a low-level voltage in accordance with an instruction from the control unit 311. In addition, the second determination result output by the second determination circuit 34 is input to the input / output I / F 313. The control unit 311 acquires the second determination result input to the input / output I / F 313.

[0044] The input / output I / F 313 of the microcomputer 31 has a plurality of pin terminals (PIN(1), PIN(2), . . . PIN(n)). In this embodiment, the IPD 32a is connected to PIN(1) of the microcomputer 31 via a control line. The IPD 32b is connected to PIN(2) of the microcomputer 31 via a control line. The IPD 32c is connected to PIN(3) of the microcomputer 31 via a control line. When the number of the plurality of IPDs 32 is three, the second determination circuit 34 is connected to, for example, PIN(4) of the microcomputer 31 via a control line, however, the pin terminal to which the second determination circuit 34 is connected is not limited to this.

[0045] The control unit 311 of the microcomputer 31 applies voltage to the IPDs 32a to 32c via PINs (1) to (3) and controls the output of power to the load 4 downstream of the IPDs 32a to 32c. The control unit 311 also acquires the second judgment result output from the second judgment circuit 34 via PIN (4) and judges whether or not any of the IPDs 32a to 32c is in a faulty state based on the acquired second judgment result. Specifically, when a low-level voltage is output from the second judgment circuit, the control unit 311 judges that no IPD 32 is in a faulty state. When a high-level voltage is output from the second judgment circuit, the control unit 311 judges that any of the IPDs 32a to 32c is in a faulty state. That is, the control unit 311 can judge whether or not any of the three IPDs 32 is in a faulty state based on the output or input at the four pin terminals. When the control unit 311 determines that any of the IPDs 32 is in a faulty state, the control unit 311 may transmit, for example, to the power supply device 1, a signal requesting the power supply device 1 to stop power supply to the in-vehicle device 3. The control unit 311 may also execute a process of identifying the IPD 32 in a faulty state.

[0046] According to the above configuration, the control unit 311 of the microcomputer 31 can determine whether or not the IPD 32 is in a faulty state based on the voltage indicating the second determination result output from the second determination circuit 34. Furthermore, since the microcomputer 31 can determine whether or not the IPD 32 is in a faulty state based on inputs and outputs at the same number of pin terminals as the IPD 32 and at the pin terminals to which the second determination circuit 34 is connected, the number of pin terminals used to connect one IPD 32 can be reduced, and a large number of IPDs 32 can be connected to the microcomputer 31. This allows the control unit 311 to efficiently determine the faulty state of the switching device (IPD 32).

[0047] (Embodiment 2) The control unit 311 of the microcomputer 31 according to the second embodiment acquires a voltage indicating the second judgment result output by the second judgment circuit 34 at a predetermined cycle, and if the acquired voltage is a high level voltage a predetermined number of times or more in succession, judges that at least one of the IPDs 32a to 32c is in a faulty state. The following describes the differences between the second embodiment and the first embodiment. The other configurations are the same as those of the first embodiment, except for the configurations described below. For this reason, the same reference symbols as those of the first embodiment are used for the components that are the same as those of the first embodiment, and the description thereof will be omitted.

[0048] 3 is a timing chart showing the input and output of the first determination circuit 33 according to the second embodiment. The first determination circuit 33 receives a voltage indicating the state of voltage application from the microcomputer 31 to the IPD 32 and a voltage value of the power output by the IPD 32 indicating the state of power output from the IPD 32 to the downstream load 4. When the voltage value of the power input to the first determination circuit 33 is higher than a predetermined threshold, a high-level voltage is input to the first determination circuit 33, and when the voltage value of the power is equal to or lower than the predetermined threshold, a low-level voltage is input to the first determination circuit 33. That is, the voltage value of the power input to the first determination circuit 33 is converted into a binary value and then input.

[0049] The first determination circuit 33 outputs a low level voltage as the first state determination result when high level voltages are input as both the power application state and the power output state, or when low level voltages are input as both, i.e., when the power application state and the power output match and correspond. Also, when high level voltages and low level voltages are input as the power application state or the power output state, i.e., when the power application state and the power output do not match and correspond, the first determination circuit outputs a high level voltage as the first determination result.

[0050] When the IPD32 is not in a faulty state, if the voltage applied by the microcomputer 31 is switched from a low-level voltage to a high-level voltage, the IPD32 starts outputting power. Also, when the voltage applied by the microcomputer 31 is switched from a high-level voltage to a low-level voltage, the IPD32 starts outputting power. Note that the IPD32 switches between the presence and absence of power output after the applied voltage is switched, so there is a time difference between the time when a change in voltage indicating the application state of the voltage input to the first determination circuit is detected (application time point) and the time when a change in voltage indicating the output state of power is detected (output time point), and the output time is delayed with respect to the application time point. During the time from the application time point to the output time point, the power application state and the power output do not match, and even though the IPD32 is not in a faulty state, the first determination circuit outputs a high-level voltage as the first determination result.

[0051] When the first determination circuit 33 outputs a high-level voltage, the second determination circuit 34 outputs a high-level voltage to the microcomputer 31 as the second determination result. Therefore, the control unit 311 of the microcomputer 31 may obtain a high-level voltage as the second determination result even if there is no IPD 32 in a faulty state. Therefore, the control unit 311 of the microcomputer 31 obtains a voltage indicating the second determination result at a predetermined period, and when the obtained voltage is a high-level voltage for a predetermined number of times or more in succession, it determines that at least one of the IPDs 32a to 32c is in a faulty state. Note that the predetermined period is, for example, a period having an interval of a time (a turn-on time or a turn-off time due to the switching characteristics of the IPD 32) assumed as a time difference between the application time point and the output time point. Note that, in this case, the predetermined number of times is two times. That is, when the voltage obtained as the second determination result is a high-level voltage for two consecutive times, the control unit 311 determines that one of the IPDs 32a to 32c is in a faulty state. The predetermined period and the predetermined number of times are not limited to those described above, and the shorter the predetermined period, the greater the predetermined number of times.

[0052] FIG. 4 is a flowchart showing the procedure of the failure determination process according to the second embodiment. The control unit 311 of the microcomputer 31 acquires a voltage indicating the second determination result output from the second determination circuit 34 (S1). The control unit 311 judges whether or not the voltage indicating the second determination result is a high-level voltage (S2). If the voltage indicating the second determination result is not a high-level voltage (S2: NO), the control unit 311 returns the process to S1 and acquires the voltage indicating the second determination result again. The acquisition of the voltage in S1 is performed at a predetermined cycle. If the voltage indicating the second determination result is a high-level voltage (S2: YES), the control unit 311 judges whether or not the acquired voltage is a high-level voltage a predetermined number of times in succession (S3). If the acquired voltage is not a high-level voltage a predetermined number of times in succession (S3: NO), the control unit 311 returns the process to S1. If the acquired voltage is a high-level voltage a predetermined number of times in succession (S3: YES), the control unit 311 determines that any one of the IPDs 32a to 32c is in a faulty state (there is an IPD 32 in a faulty state) (S4), and ends the process.

[0053] According to the above processing, even if the control unit 311 of the microcontroller 31 obtains a high-level voltage as the second judgment result when there is no IPD 32 in a faulty state, it is possible to prevent or reduce erroneous judgment that any of the IPDs 32 is in a faulty state.

[0054] (Embodiment 3) The in-vehicle device 3 according to the third embodiment includes a time constant increasing circuit that increases the time constant of the input of the state of voltage application from the microcomputer 31 to the IPD 32 to the first determination circuit 33. The following describes the differences between the third embodiment and the first embodiment. The other configurations, except for the configurations described below, are common to the first embodiment. For this reason, the same reference symbols as those in the first embodiment are used for the components common to the first embodiment, and the description thereof will be omitted.

[0055] 5 is a block diagram showing a configuration of a main part of an in-vehicle device 3 according to embodiment 3. The in-vehicle device 3 according to embodiment 3 includes a time constant increasing circuit 35 provided for each of the first determination circuits 33. The time constant increasing circuit 35 is configured with a resistor 351 and a capacitor 352, and is provided between a control line connecting the microcomputer 31 and the IPD 32, and the first determination circuit 33. That is, the time constant increasing circuit is configured with an RC filter.

[0056] FIG. 6 is a timing chart showing the input and output of the first determination circuit 33 according to the third embodiment. The time constant increasing circuit 35 increases the time constant when the voltage indicating the applied state of the voltage to the IPD 32, which is input to the first determination circuit 33, is switched, and slows down the rise or fall of the signal indicating the voltage. The first determination circuit 33 determines that a high-level voltage has been input when the voltage value indicating the applied state is higher than a predetermined value (for example, the average value of the voltage value of the low-level voltage and the voltage value of the high-level voltage), and determines that a low-level voltage has been input when the voltage value indicating the applied state is equal to or lower than the predetermined value. As a result, the application time (the time when the switching of the applied voltage is detected) is delayed compared to when the time constant increasing circuit 35 is not provided (see FIG. 3), and the time difference between the application time and the output time is shortened. When the IPD 32 is not in a faulty state, the time during which the first determination circuit outputs a high-level voltage is shortened, and accordingly the time during which the second determination circuit 34 outputs a high-level voltage to the microcomputer 31 is also shortened.

[0057] According to the above configuration, when the IPD 32 is not in a faulty state, it is possible to shorten the time during which the voltage indicating the second determination result obtained by the control unit 311 of the microcomputer 31 from the second determination circuit 34 is at a high level. This makes it possible to prevent or reduce the occurrence of the control unit 311 of the microcomputer 31 erroneously determining that any of the IPDs 32 is in a faulty state when there is no IPD 32 in a faulty state.

[0058] (Embodiment 4) The in-vehicle device 3 according to the fourth embodiment includes a time constant increasing circuit that increases the time constant of the voltage output indicating the first judgment result from the first judgment circuit 33. The following describes the differences between the fourth embodiment and the first embodiment. Except for the configuration described below, the other configurations are common to the first embodiment. Therefore, the components common to the first embodiment are given the same reference symbols as the first embodiment, and the description thereof will be omitted.

[0059] 7 is a block diagram showing a configuration of a main part of an in-vehicle device 3 according to embodiment 4. The in-vehicle device 3 according to embodiment 3 includes a time constant increasing circuit 35 provided for each first determination circuit 33. The time constant increasing circuit 35 is configured with a resistor 351 and a capacitor 352, and is provided between the first determination circuit 33 and the second determination circuit 34. That is, the time constant increasing circuit is configured with an RC filter.

[0060] FIG. 8 is a timing chart showing the input and output of the first judgment circuit 33 according to the fourth embodiment. In FIG. 8, the voltage indicating the first judgment result indicates the voltage input to the second judgment circuit 34 via the time constant increasing circuit 35. The time constant increasing circuit 35 increases the time constant when the voltage indicating the first judgment result output by the first judgment circuit 33 is switched, and slows down the rise or fall of the signal indicating the voltage. The second judgment circuit 34 determines that a high-level voltage has been input when the voltage indicating the first judgment result becomes higher than a predetermined value (for example, the average value of the voltage value of the low-level voltage and the voltage value of the high-level voltage), and determines that a low-level voltage has been input when the voltage value of the voltage indicating the applied state becomes equal to or lower than a predetermined value. The time constant increasing circuit 35 increases the time constant of the signal of the voltage indicating the first judgment result, thereby reducing the speed at which the voltage value of the voltage indicating the first judgment result rises due to the difference between the voltage indicating the applied state and the voltage indicating the output state during the time between the application time point and the output time point. Before the voltage indicating the first judgment result becomes higher than a predetermined value, the voltage indicating the application state and the voltage indicating the output state match, and the first judgment circuit 33 outputs a low-level voltage, so that when the IPD 32 is not in a fault state, a high-level voltage is prevented from being input to the second judgment circuit 34. Accordingly, when the IPD 32 is not in a fault state, the second judgment circuit 34 is prevented from outputting a high-level voltage to the microcomputer 31.

[0061] According to the above configuration, when the IPD 32 is not in a faulty state, the control unit 311 of the microcomputer 31 is prevented from acquiring a high-level voltage as the second determination result from the second determination circuit 34. This makes it possible to prevent or reduce the occurrence of the control unit 311 of the microcomputer 31 erroneously determining that any of the IPDs 32 is in a faulty state when there is no IPD 32 in a faulty state.

[0062] (Embodiment 5) When the control unit 311 of the microcomputer 31 according to the fifth embodiment determines that at least one IPD 32 is in a fault state based on the acquired second determination result, the control unit 311 acquires a current value corresponding to the power output downstream from the IPD 32, and determines whether each IPD 32 is in a fault state based on the state of voltage application to the IPD 32, the current value acquired from the IPD 32, and the input current value of the power supplied from the power supply device 1, thereby identifying the IPD 32 in a fault state. The following describes the differences between the fifth embodiment and the first embodiment. The other configurations, except for the configuration described below, are common to the first embodiment. For this reason, the same reference symbols as those in the first embodiment are used for the components common to the first embodiment, and the description thereof will be omitted.

[0063] FIG. 9 is a block diagram showing a main configuration of a power supply system S according to a fifth embodiment. The power supply system S is mounted on a vehicle M and includes a power supply device 1, an upstream device 2, an in-vehicle device 3, and a plurality of loads 4. The power supply device 1 is a power supply that outputs a direct current. The upstream device 2 may be an integrated ECU mounted on the vehicle M, and is connected to the positive electrode of the power supply device 1 and the in-vehicle device 3. The in-vehicle device 3 is connected to the upstream device 2 and one end of the plurality of loads 4. The negative electrode of the power supply device 1 and the other end of the load 4 are grounded. The upstream device 2 may be a front zone ECU mounted on the front zone of the vehicle M, and the in-vehicle device 3 may be a left zone ECU mounted on the left zone of the vehicle M or a right zone ECU mounted on the right zone. 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 the upstream of the current, and the load 4 side is the downstream of the current. In FIG. 9, the first determination circuit 33 and the second determination circuit 34 are omitted.

[0064] The upstream device 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 upstream device 2. The IPD 22 corresponds to an upstream opening and closing 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 in-vehicle device 3.

[0065] The in-vehicle device 3 includes a microcomputer 31 and a plurality of IPDs 32. Power supplied from the power supply device 1 to the in-vehicle device 3 via the IPD 22 of the upstream device 2 is distributed to the plurality of IPDs 32 and output to a downstream load 4 via each IPD 32. The IPD 32 corresponds to a switching device. The microcomputer 31 controls the output of power to the downstream side of the IPD 32, and obtains a current value corresponding to the power output by the IPD 32 to the downstream side.

[0066] The microcomputer 21 of the upstream device 2 and the microcomputer 31 of the in-vehicle device 3 are connected by a communication bus B, and can communicate with each other using a communication protocol such as CAN (Control Area Network), CAN-FD, or Ethernet (registered trademark). The microcomputer 21 of the upstream device 2 transmits to the microcomputer 31 of the in-vehicle device 3 the current value of the power output by the IPD 22 to the downstream side, that is, the current value (input current value) of the power supplied to the in-vehicle device 3. The IPD 22 (upstream switching device) and the IPD 32 (switching device) may be provided in one 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 may control the output of power to the downstream side of the IPD 22 of the upstream device 2, and may also obtain the current value of the power output by the IPD 22 to the downstream side.

[0067] FIG. 10 is a block diagram showing a connection example between the microcomputer 31 and the IPD 32 of the in-vehicle device 3 according to the fifth embodiment. FIG. 10 shows a connection example of one IPD 32 (IPD 32a) to the microcomputer 31, and the other IPDs 32 are omitted. The microcomputer 31 according to the fifth embodiment includes an in-vehicle communication unit 314. The in-vehicle communication unit 314 is an input / output interface using 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 current value (input current value) of the power output by the IPD 22 of the integrated ECU 2 to the downstream side, i.e., the power supplied to the individual ECU 3.

[0068] 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 that connects the IPD 22 of the integrated ECU 2 and the IPD 32 of the individual ECU is connected to the power receiving terminal 321, and the power receiving terminal 321 receives power supplied from the upstream side.

[0069] The power output terminal 322 is connected to a power line that connects the IPD 32 and a load, and outputs the power received by the power receiving terminal 321 to the downstream load 4.

[0070] 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 the voltage applied from the microcomputer 31 to the voltage application terminal 323. Specifically, the IPD 32 includes, for example, an N-channel type FET (Field Effect Transistor). 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 type FET or a mechanical relay, etc.

[0071] The current value 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 value detection terminal 324 is connected to PIN(2) of the input / output I / F 313. The current value detection terminal 324 outputs a current value corresponding to the power output from the power output terminal 322 to the microcomputer 31. 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 value detection terminal 324 is also connected to the current detection circuit, and outputs 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 to the microcomputer 31. A pull-down resistor Rd 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 value detection terminal 324. That is, the microcomputer 31 can obtain a voltage value that is proportional to the current value of the power output from the power output terminal 322 of the IPD 32 (output current value).

[0072] As described above, each of the other IPDs 32 included in the individual ECU 3 also includes the power receiving terminal 321, the power output terminal 322, the voltage application terminal 323, and the current value detection terminal 324. In addition, each of the IPDs 32 is connected to two pin terminals (PIN) in the microcomputer 31.

[0073] The first determination circuit 33 is connected to a control line connecting PIN(1) of the microcomputer 31 and a voltage application terminal 323 of the IPD 32, and to a power line connecting a power output terminal 322 of the IPD 32 and the load 4. The second determination circuit 34 is connected to the first determination circuit 33 and a pin terminal of the microcomputer 31. When the number of the multiple IPDs 32 is three, the second determination circuit 34 is connected to, for example, PIN(7) of the microcomputer 31, but the pin terminal to which the second determination circuit 34 is connected is not limited to this.

[0074] 11 is a flowchart showing the procedure of the failure determination process according to the fifth embodiment. The control unit 311 of the microcomputer 31 acquires the second determination result from the second determination circuit 34 (S11). The control unit 311 judges whether or not there is an IPD 32 in a faulty state based on the acquired second determination result (S12). If the control unit 311 acquires a high-level voltage as the second determination result in S12, it judges that there is an IPD 32 in a faulty state, and if it acquires a low-level voltage, it judges that there is no IPD 32 in a faulty state. If there is no IPD 32 in a faulty state (S12: NO), the control unit 311 returns the process to S11. If there is an IPD 32 in a faulty state (S12: YES), the control unit 311 specifies the IPD 32 to be subjected to failure determination (S13). In S13, the control unit 311 specifies the IPDs 32a to 32c in order as failure determination targets. That is, when S13 is executed for the first time, the IPD 32a is specified as the object to be judged for failure, and when S13 is executed for the second time after the process is returned, the IPD 32b is specified as the object to be judged for failure.

[0075] The control unit 311 acquires the state of voltage application to the IPD 32 (S14). 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 that is the target of failure judgment (S15). The control unit 311 also acquires the output current values ​​of other IPDs 32 that are not the target of failure judgment (S16). The control unit 311 acquires the output current value of the IPD 32 by performing a calculation 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 (S17).

[0076] The control unit 311 of the microcomputer 31 determines whether or not the voltage applied to the IPD 32 that is the failure determination target is a high-level voltage (S18). If the voltage applied to the IPD 32 is a high-level voltage (S18: YES), the control unit 311 determines whether or not the output current value of the IPD 32 that is the failure determination target is equal to or greater than a predetermined threshold (S19). The threshold in S19 is a current value of a cutoff characteristic that has a minimum current value among cutoff characteristics for a load that is assumed to be connected to the IPD 32. The control unit 311 may determine whether or not there is an output current from the IPD 32, that is, whether the output current value is a value higher than 0 A or 0 A. If the output current value of the IPD 32 that is the failure determination target is equal to or greater than the predetermined threshold (S19: YES), the control unit 311 determines whether or not the input current value to the IPD 32 matches the total of the output current values ​​of all the IPDs 32 included in the individual ECU 3 (S20). If the sum of the input current value and the output current value match (S20: YES), the control unit 311 determines that the IPD 32 that is the target of failure judgment is in a normal state (S21). If the output current value of the IPD 32 that is the target of failure judgment is not equal to or greater than a predetermined threshold (is less than the threshold) (S19: NO), or if the sum of the input current value and the output current value do not match (S20: NO), the control unit 311 determines that the IPD 32 that is the target of failure judgment is in an open failure state (S22). Note that, if it is determined that the IPD 32 is in an open failure state, the control unit 311 may, for example, stop control of the IPD 32 that is determined to be in an open failure state.

[0077] When the voltage applied to the IPD 32 is not a high-level voltage (is a low-level voltage) (S18: NO), the control unit 311 determines whether or not the output current value of the IPD 32 that is the failure determination target is equal to or greater than a predetermined threshold (S23). The threshold in S10 is a current value of a cutoff characteristic that has a minimum current value among cutoff characteristics for a load that is assumed to be connected to the IPD 32. The control unit 311 may determine whether or not there is an output current of the IPD 32, that is, whether the output current value is a value higher than 0 A or 0 A. When the output current value of the IPD 32 that is the failure determination target is not equal to or greater than a predetermined threshold (is less than the threshold) (S23: NO), the control unit 311 determines whether or not the input current value to the IPD 32 matches the total of the output current values ​​of all the IPDs 32 provided in the individual ECU 3 (S24). When the input current value matches the total of the output current value (S24: YES), the control unit 311 determines that the IPD 32 that is the failure determination target is in a normal state (S25). If the output current value of the IPD 32 that is the failure judgment target is equal to or greater than a predetermined threshold value (S23: YES), or if the sum of the input current value and the output current value does not match (S24: NO), the control unit 311 judges that the IPD 32 that is the failure judgment target is in a short-circuit fault state (S26). Note that, if it is determined that the IPD 32 is in a short-circuit fault state, the control unit 311 may, for example, transmit a signal to the microcomputer 21 of the integrated ECU 2 to request the stop of power supply to the individual ECUs 3.

[0078] After determining the state of the IPD 32 in S21, S22, S25, or S26, the control unit 311 determines whether all the IPDs 32 provided with the first determination circuits 33 connected to the second determination circuit 34 that output the second determination result have been determined to be fault-determined (S27). If all the IPDs 32 have not been determined to be fault-determined (S27: NO), the control unit 311 returns the process to S13, changes the IPD 32 to be determined to be fault-determined, and continues the fault determination process. If all the IPDs 32 have been determined to be fault-determined (S27: YES), the control unit 311 ends the process. The control unit 311 may store the state of the IPD 32 determined in S21, S22, S25, or S26 in a determination result table stored in the storage unit.

[0079] According to the above configuration and processing, the control unit 311 can identify the IPD 32 in a faulty state. The determination of the presence or absence of the IPD 32 in a faulty state is periodically performed, whereas the determination of whether or not each IPD 32 is in a faulty state is performed by an event-driven method triggered by the determination of at least one IPD 32 in a faulty state. The control unit 311 determines the presence or absence of the IPD 32 in a faulty state by a simple process based on the voltage indicating the second determination result, and when it is determined that at least one IPD 32 is in a faulty state, it determines whether or not each IPD 32 is in a faulty state, thereby making it possible to efficiently determine the fault state of the switching device (IPD 32). Note that the storage unit 312 of the microcomputer 31 may store a table (fault determination table) that stores the state of the IPD 32 for the conditions of the voltage application state, the output current value of the IPD 32, and whether or not the sum of the input current value and the output current value matches, and the control unit 311 may determine the state of the IPD 32 based on the fault determination table.

[0080] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the scope of the claims and equivalents to the scope of the claims. In addition, the independent claims and dependent claims described in the claims can be combined with each other in all combinations regardless of the reference format. Furthermore, the claims use a format in which a claim references two or more other claims (multiple claim format), but this is not limited to this. A format in which a multiple claim (multi-multi claim) that references at least one multiple claim may be used. [Explanation of symbols]

[0081] 1 Power supply 2 Upstream device 21 Microcomputer 22 IPD 3 Onboard equipment 31 Microcomputer 311 Control Unit 312 Storage section 313 Input / Output Interface 314 In-vehicle communication unit 315 Internal Bus 32 IPD 321 Power receiving terminal 322 Power output terminal 323 Voltage application terminal 324 Current detection terminal 33 First judgment circuit 34 Second judgment circuit 35 Time constant increase circuit 4. Load A storage medium B Communication bus M Vehicle P Computer Program S Power Supply System

Claims

1. A plurality of switching devices are provided in parallel on a power line extending from a power supply device mounted on a vehicle; a control unit that applies a voltage to each of the switching devices to control an output of power from each of the switching devices to a downstream side in a current flow direction from the power supply device; a first determination circuit provided in each of the switching devices and configured to output a first determination result indicating whether or not a state of voltage application to the switching device by the control unit corresponds to a state of power output to a downstream side by the switching device; a second determination circuit that determines whether or not all of the first determination results outputted from the plurality of first determination circuits indicate a correspondence; and Equipped with The control unit is obtaining the second judgment result from the second judgment circuit; Based on the acquired second determination result, it is determined whether or not there is a switching device in a fault state among the plurality of switching devices. In-vehicle device.

2. The first determination circuit is The control unit is connected to a control line that connects the control unit and the switchgear, and to a power line that connects the switchgear and a downstream load, Obtaining a voltage application state from the control line; Acquires the power output state from the power line The in-vehicle device according to claim 1 .

3. The first determination circuit is When the control unit applies a high-level voltage to the switching device, if the voltage value of the power output by the switching device to the downstream side is higher than a predetermined threshold, or when the control unit applies a low-level voltage to the switching device, if the voltage value of the power output by the switching device to the downstream side is equal to or lower than a predetermined threshold, outputting a low-level voltage indicating that the voltage application state and the power output state correspond to each other; When the control unit applies a high-level voltage to the switching device, if the voltage value of the power output by the switching device to the downstream side is equal to or lower than a predetermined threshold, or when the control unit applies a low-level voltage to the switching device, if the voltage value of the power output by the switching device to the downstream side is higher than a predetermined threshold, a high-level voltage indicating that the voltage application state and the power output state do not correspond is output. The in-vehicle device according to claim 1 .

4. The second determination circuit is acquiring voltages output from the plurality of first determination circuits, outputting a low-level voltage to the control unit when the voltages acquired from the first determination circuits are all low-level voltages; When at least one of the voltages obtained from the first determination circuits is a high-level voltage, a high-level voltage is output to the control unit. The vehicle-mounted device according to claim 3.

5. When a high-level voltage is input from the second determination circuit, the control unit determines that at least one of the switching devices is in a fault state. The vehicle-mounted device according to claim 4.

6. The control unit is acquiring the voltage output by the second determination circuit at a predetermined period; When the voltage acquired from the second determination circuit is a high level voltage a predetermined number of times in succession, it is determined that at least one of the switching devices is in a fault state. The vehicle-mounted device according to claim 4.

7. A time constant increasing circuit is provided for increasing the time constant of the input of the voltage application state to the first determination circuit. The in-vehicle device according to claim 1 .

8. a time constant increasing circuit for increasing the time constant of the output of the first judgment result from the first judgment circuit; The in-vehicle device according to claim 1 .

9. the first determination circuit is composed of an exclusive OR circuit, The second determination circuit is composed of a logical OR circuit. The in-vehicle device according to claim 1 .

10. The control unit is Obtaining the second determination result; determining whether or not at least one of the switching devices is in a fault state based on the second determination result; When it is determined that at least one of the switching devices is in a fault state, Acquire a current value corresponding to the power output from the switching device to the downstream side; Whether or not the switching device is in a fault state is determined based on a state of voltage application to the switching device, a current value acquired from the switching device, and an input current value based on the power supplied from the power supply device. The in-vehicle device according to claim 1 .

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