Power source control device and power source control program

Abstract

To provide a power source control device capable of satisfying a request response time even if a response time of a circuit is prolonged by a secular change, and a power source control program.SOLUTION: A power source control device comprises an interruption mechanism, a comparator, a latch circuit, a bypass circuit, and a controller. The interruption mechanism interrupts a connection of a first system and a second system which are different power supply systems. The comparator outputs an abnormality detection signal when a system voltage becomes equal to or lower than an abnormality threshold. The latch circuit latches the abnormality detection signal, outputs an interruption signal and causes the interruption mechanism to perform the interruption. The bypass circuit bypasses the latch circuit. The controller performs control in such a manner that the system voltage becomes equal to or lower than the abnormality threshold in a diagnosis mode and, when a required time from output of the abnormality detection signal or the interruption signal to the interruption of the interruption mechanism is longer than a specific time, causes the abnormality detection signal to be outputted from the comparator to the interruption mechanism via the bypass circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The disclosed embodiments relate to a power supply control device and a power supply control program. [Background technology]

[0002] There is a power supply control device that has a disconnection mechanism that disconnects the connection between a first system that supplies power from a first power source to a load and a second system that supplies power from a second power source to a load, and that disconnects the disconnection mechanism when the first power source fails and performs backup control using the second power source (see, for example, Patent Document 1).

[0003] Such a power supply control device may be designed so that the response time from when a power supply failure is detected to when the cutoff mechanism is cutoff satisfies a required response time (for example, within 100 μs). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-043533 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of a power supply control device, if the circuit that shuts off the shutoff mechanism is configured as a hardware circuit, the response time may become longer due to aging of the circuit, and the required response time may not be met.

[0006] One aspect of the embodiment has been made in consideration of the above, and aims to provide a power supply control device and a power supply control program that can meet the required response time even if the circuit response time becomes longer due to changes over time. [Means for solving the problem]

[0007] A power supply control device according to an embodiment includes a cutoff mechanism, a comparator, a latch circuit, a bypass circuit, and a controller. The cutoff mechanism cuts off a connection between a first system that supplies power from a main power source to a load and a second system that supplies power from a backup power source to the load. The comparator compares a system voltage, which is the voltage of the first system or the second system, with an abnormality threshold and outputs an abnormality detection signal when the system voltage falls below the abnormality threshold. The latch circuit latches the abnormality detection signal and outputs a cutoff signal, causing the cutoff mechanism to cut off the connection between the first system and the second system. The bypass circuit bypasses the latch circuit. In a diagnostic mode, the controller controls the system voltage to fall below the abnormality threshold and measures the time required from the output of the abnormality detection signal or the cutoff signal to the cutoff of the connection between the first system and the second system. If the required time is longer than a specified time, the controller switches the bypass circuit from disabled to enabled and causes the comparator to output the abnormality detection signal to the cutoff mechanism via the bypass circuit. [Effects of the Invention]

[0008] In a power supply control device according to an embodiment, if the time required for disconnecting the first and second systems after an abnormality detection signal or a shutdown signal is output in a diagnostic mode is longer than a specified time, the bypass circuit is enabled. This allows the power supply control device to shut off the shutdown mechanism by outputting the abnormality detection signal directly from the comparator to the shutdown mechanism, without passing through the latch circuit, if the response time of the latch circuit becomes longer due to aging. Therefore, even if the response time of the latch circuit becomes longer due to aging, the power supply control device can shorten the time from outputting the abnormality detection signal to shutting off the shutdown mechanism, thereby meeting the required response time. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of a power supply control device according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the operation of the power supply control device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating the operation of the power supply control device according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating the operation of the power supply control device according to the embodiment. [Figure 5] FIG. 5 is a diagram illustrating the operation of the power supply control device according to the embodiment. [Figure 6] FIG. 6 is a diagram illustrating the operation of the power supply control device according to the embodiment. [Figure 7] FIG. 7 is a flowchart illustrating an example of processing executed by the controller according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of a power supply control device and a power supply control program will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. The following description will be given taking as an example a power supply control device that is installed in a vehicle with an automatic driving function and supplies power to a load.

[0011] In the following, a case will be described in which the vehicle in which the power supply control device is installed is an electric vehicle or a hybrid vehicle, but the vehicle in which the power supply control device is installed may also be an engine vehicle that runs on an internal combustion engine.

[0012] [1. Configuration of the power supply control device according to the embodiment] Fig. 1 is an explanatory diagram showing the configuration of a power supply control device according to an embodiment. As shown in Fig. 1, the power supply control device 1 according to the embodiment is connected to a main power supply 10, a first load 101, and a second load 102. The power supply control device 1 is also connected to an automatic operation control device (not shown).

[0013] The power supply control device 1 includes a first system 110 and a second system 120. The first system 110 is a power supply system that supplies power from a main power supply 10 to a first load 101. The second system 120 is a power supply system that supplies power from a backup power supply 20 to a second load 102.

[0014] The first load 101 includes a load for autonomous driving. The first load 101 includes a steering motor, an electric brake device, an in-vehicle camera, etc. that operate during autonomous driving. The first load 101 may also include a display, an air conditioner, an audio device, a video device, various lights, etc.

[0015] The second load 102 has some of the functions for automatic driving that the first load 101 has. The second load 102 includes the minimum devices required for FOP (fail-safe control), such as a steering motor, an electric brake device, and a radar. The second load 102 may also include a display, an air conditioner, an audio device, a video device, various lights, and the like.

[0016] The first load 101 and the second load 102 may be the same load. The first load 101 and the second load 102 operate using power supplied from at least one of the main power supply 10 and the backup power supply 20 via the power supply control device 1.

[0017] The automatic driving control device is a device that controls automatic driving of a vehicle by operating a first load 101 and a second load 102. If a power supply failure such as a ground fault occurs in the first system 110 during automatic driving, the automatic driving control device can implement FOP (fail-safe control) using the second load 102. Furthermore, if a power supply failure such as a ground fault occurs in the second system 120, the automatic driving control device can implement FOP using the first load 101.

[0018] The main power supply 10 is, for example, a lead battery. The battery of the main power supply 10 may be any secondary battery other than a lead battery. The backup power supply 20 is a backup power supply in case the main power supply 10 is unable to supply power. The backup power supply 20 is, for example, a lithium ion battery. The battery of the backup power supply 20 may be any secondary battery other than a lithium ion battery. The backup power supply 20 may also be included in the power supply control device 1.

[0019] The power supply control device 1 includes a cutoff mechanism 2, a detector 3, an AND circuit 4, a controller 5, and a backup power supply 20. The cutoff mechanism 2 includes a switch that cuts off the connection between the first system 110 and the second system 120. Specifically, the cutoff mechanism 2 includes a first switch 21, a second switch 22, and a voltage sensor 6.

[0020] The first switch 21 and the second switch 22 are, for example, field effect transistors (FETs). The first switch 21 and the second switch 22 are connected in series between the first system 110 and the second system 120.

[0021] The first switch 21 and the second switch 22 are controlled to be turned on and off by the controller 5. When the first switch 21 and the second switch 22 are turned on, they electrically connect both terminals, and when they are turned off, they cut off the electrical connection between both terminals.

[0022] The cutoff mechanism 2 electrically connects the first system 110 and the second system 120 by turning on both the first switch 21 and the second switch 22. The cutoff mechanism 2 also cuts off the electrical connection between the first system 110 and the second system 120 by turning off at least one of the first switch 21 and the second switch 22.

[0023] The voltage sensor 6 is provided on a connection line connecting the first switch 21 and the second switch 22. The voltage sensor 6 detects a system voltage V1 which is the voltage of the first system 110 or the second system 120, and outputs the detection result to the controller 5.

[0024] The power supply control device 1 also includes a bypass switch 23 and a battery switch 24. The bypass switch 23 and the battery switch 24 are, for example, FETs. The bypass switch 23 and the battery switch 24 are controlled to be turned on and off by the controller 5. The bypass switch 23 and the battery switch 24 electrically connect both terminals when turned on, and cut off the electrical connection between both terminals when turned off.

[0025] The bypass switch 23 is a switch that bypasses the cutoff mechanism 2. In other words, the bypass switch 23 is a switch that bypasses the first switch 21 and the second switch 22 and connects the first system 110 and the second system 120 together.

[0026] When the cutoff mechanism 2 is in a cutoff state, the power supply control device 1 can supply power to the first load 101 and the second load 102 from at least one of the main power supply 10 and the backup power supply 20 without going through the cutoff mechanism 2 by turning on the bypass switch 23.

[0027] The battery switch 24 is connected between the backup power supply 20 and the second system 120. When the battery switch 24 is turned on, it electrically connects the backup power supply 20 and the second system 120, and when it is turned off, it cuts off the electrical connection between the backup power supply 20 and the second system 120.

[0028] The detector 3 is a circuit that compares the system voltage V1 with the abnormality threshold Vth in the normal mode, and causes the cutoff mechanism 2 to cut off the connection between the first system 110 and the second system 120 when the system voltage V1 falls below the abnormality threshold Vth.

[0029] Specifically, the detector 3 includes a comparator 31, a latch circuit 32, and a bypass circuit 33. The comparator 31 compares the system voltage V1 output from the voltage sensor 6 with an abnormality threshold Vth. The abnormality threshold Vth is the lower limit of the system voltage V1 in a normal state in which no failure occurs in the first system 110 or the second system 120. When the system voltage V1 drops below the abnormality threshold Vth, the comparator 31 outputs an abnormality detection signal S1 to the latch circuit 32. The comparator 31 may be configured to output the abnormality detection signal S1 also to the AND circuit 4 and the controller 5.

[0030] The latch circuit 32 is a monostable multivibrator. When the abnormality detection signal S1 is input from the comparator 31, the latch circuit 32 latches the abnormality detection signal S1 and outputs a shutdown signal S2, which is a one-shot pulse signal with a predetermined pulse width, to the AND circuit 4 and the controller 5. The predetermined pulse width is, for example, 50 ms. However, the predetermined pulse width is not limited to 50 ms.

[0031] Specifically, the predetermined pulse width may be a value other than 50 ms as long as it is longer than the oscillation period of the system voltage V1 that is expected to occur due to noise. This allows the cutoff mechanism 2 to maintain the cutoff state while the abnormality detection signal S1 is high, even if the system voltage V1 temporarily exceeds the abnormality threshold Vth due to noise or the like. This allows the power supply control device 1 to suppress chattering, in which the cutoff mechanism 2 repeatedly turns on and off.

[0032] The bypass circuit 33 is a circuit that bypasses the latch circuit 32 and the AND circuit 4. In other words, the bypass circuit 33 is a circuit that can directly connect the comparator 31 to the cutoff mechanism 2 and the battery switch 24 without passing through the latch circuit 32 and the AND circuit 4.

[0033] The bypass circuit 33 may be configured to bypass only the latch circuit 32. In other words, the bypass circuit 33 may be configured to be able to directly connect the comparator 31 and the AND circuit 4 without passing through the latch circuit 32.

[0034] The bypass circuit 33 includes a bypass switch 34. The bypass switch 34 is controlled to be turned on and off by the controller 5. When the bypass switch 34 is turned on, the bypass circuit 33 directly connects the comparator 31 to the cutoff mechanism 2 and the battery switch 24.

[0035] The AND circuit 4 is provided between the detector 3 and the cutoff mechanism 2. The AND circuit 4 is a gate circuit that enables or disables the cutoff signal S2 input from the detector 3 in accordance with a control signal S3 input from the controller 5.

[0036] The AND circuit 4 outputs a shutdown signal S4 to the shutdown mechanism 2 and the battery switch 24 when the shutdown signal S2 is High and the control signal S3 is High (shutdown enable signal). The AND circuit 4 does not output the shutdown signal S4 except when the shutdown signal S2 is High and the control signal S3 is High (shutdown enable signal). In normal operation when no power supply failure has occurred, the controller 5 inputs a shutdown enable signal to the AND circuit 4.

[0037] Here, the first switch 21, the second switch 22, and the battery switch 24 are normally open switches. On the other hand, the bypass switch 23 is a normally closed switch. Therefore, when the vehicle is parked with the ignition switch off, power can be supplied from the main power supply 10 via the bypass switch 23 to the second load 102 (e.g., an anti-theft device, a door control device, etc.) that operates in the parked state. Also, when the ignition switch is on and the vehicle is running, the cutoff mechanism 2, in normal operation when the cutoff signal S4 is not input, turns on the first switch 21 and the second switch 22 under the control of the controller 5, thereby connecting the first system 110 and the second system 120. Also, in the event of a power failure when the cutoff signal S4 is input, the cutoff mechanism 2, in normal operation when the cutoff signal S4 is input, turns off the first switch 21 and the second switch 22 under the control of the controller 5, thereby disconnecting the first system 110 and the second system 120.

[0038] On the other hand, during normal operation when the cutoff signal S4 is not input, the battery switch 24 is turned off to cut off the connection between the backup power supply 20 and the second system 120. Furthermore, during a power failure when the cutoff signal S4 is input, the battery switch 24 is turned on by the controller 5 to connect the backup power supply 20 and the second system 120.

[0039] The detector 3 and the AND circuit 4 are configured by hardware circuits. Therefore, the detector 3 and the AND circuit 4 can instantly switch the cutoff mechanism 2 to the cutoff state when the system voltage V1 falls below the abnormality threshold Vth.

[0040] The controller 5 includes a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and various other circuits. The controller 5 may also be configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0041] The controller 5 controls the operation of the power supply control device 1 by having the CPU execute a power supply control program stored in the ROM using the RAM as a work area. The power supply control program may be stored in a storage device from the outside via a communication line or the like.

[0042] For example, during normal operation when no ground fault occurs, the controller 5 outputs a shutdown activation signal to the AND circuit 4. Furthermore, when a ground fault occurs and a shutdown signal S2 is input from the latch circuit 32, the controller 5 determines whether a power failure has occurred in the first system 110 or the second system 120. Then, the controller 5 performs fail-safe control to supply power to the load using the system in which no ground fault has occurred.

[0043] Furthermore, the controller 5 diagnoses at a predetermined timing, for example, when the power is turned on, whether or not the breaking mechanism 2 can normally break the connection between the first system 110 and the second system 120 when a ground fault occurs. Hereinafter, the operation of the power supply control device 1 controlled by the controller 5 will be described with reference to Figs. 2 to 6.

[0044] [2. Normal operation of the power supply control device] 2, during normal operation when no ground fault occurs in the first system 110 or the second system 120, the controller 5 turns on the first switch 21 and the second switch 22 and turns off the bypass switches 23 and 34 and the battery switch 24. This allows power to be supplied from the main power supply 10 to the first load 101 and the second load 102.

[0045] [3. Operation of power supply control device when a ground fault occurs] 3, in the power supply control device 1, for example, when a ground fault 200 occurs in the first system 110, the system voltage V1 drops below the abnormality threshold Vth. As a result, the comparator 31 outputs an abnormality detection signal S1, and the latch circuit 32 receives this and outputs a shutdown signal S2 to the AND circuit 4. At this time, a control signal S3, which is a shutdown enable signal, is input to the AND circuit 4 from the controller 5.

[0046] Therefore, the AND circuit 4 outputs a cutoff signal S4 to the cutoff mechanism 2 and the battery switch 24. As a result, the first switch 21 and the second switch 22 are turned off, and the battery switch 24 is turned on.

[0047] In this way, the power supply control device 1 cuts off the connection between the first system 110 and the second system 120 (hereinafter, this may be referred to as "pre-cutoff"), and connects the backup power supply 20 to the second load 102. Thereafter, the controller 5 makes a final determination as to whether the ground fault 200 has occurred in the first system 110 or the second system 120.

[0048] At this time, the controller 5 turns on the first switch 21 from the pre-shutdown state, for example. In this case, since the ground fault 200 has occurred in the first system 110, the system voltage V1 detected by the voltage sensor 6 does not return to or exceed the abnormality threshold Vth.

[0049] Thereafter, the controller 5 turns off the first switch 21, returns to the pre-shutdown state, and then turns on the second switch 22. This causes a voltage to be applied from the backup power supply 20 to the voltage sensor 6. As a result, the system voltage V1 detected by the voltage sensor 6 returns to above the abnormality threshold Vth.

[0050] In this way, the controller 5 alternately turns on the first switch 21 and the second switch 22 from the pre-shutdown state, and if the system voltage V1 returns to above the abnormal threshold Vth only when the second switch 22 is turned on, it makes a final judgment that there is a ground fault 200 in the first system 110.

[0051] The controller 5 continues the pre-shutdown state when it has finally determined that there is a ground fault 200 in the first system 110. Specifically, as shown in Fig. 4, the controller 5 controls the shutoff mechanism 2 and the battery switch 24 to maintain the shutoff mechanism 2 in the shutoff state and to keep the battery switch 24 on.

[0052] As a result, even if the one-shot pulse signal output from the latch circuit 32 switches from High to Low, the controller 5 can continue to supply power from the backup power supply 20 to the second load 102 and perform fail-safe control.

[0053] In addition, the controller 5 alternately turns on the first switch 21 and the second switch 22 from the pre-shutdown state, and if the system voltage V1 returns to or exceeds the abnormal threshold value Vth only when the first switch 21 is turned on, it makes a final determination that there is a ground fault in the second system 120.

[0054] In this case, the controller 5 controls the cutoff mechanism 2 and the battery switch 24 to maintain the cutoff mechanism 2 in the cutoff state and turn off the battery switch 24. This allows the controller 5 to perform fail-safe control by continuing to supply power from the main power supply 10 to the first load 101 while preventing the backup power supply 20 from discharging.

[0055] The controller 5 alternately turns on the first switch 21 and the second switch 22 from the pre-shutdown state, and if the system voltage V1 returns to or exceeds the abnormal threshold Vth in both cases, it determines that this is a transient voltage drop and that no ground fault has occurred. In this case, the controller 5 returns the first switch 21, the second switch 22, and the battery switch 24 to the normal states shown in FIG.

[0056] In the above description, the pre-shutdown and the final determination are performed using a single voltage sensor 6, but this is not limiting. For example, in addition to the voltage sensor 6, a voltage sensor may be provided for each of the first system 110 and the second system 120. The comparator 31 performs pre-shutdown by comparing the first system voltage detected by the voltage sensor of the first system 110 or the second system voltage detected by the voltage sensor of the second system 120 with a ground fault threshold. Upon receiving the shutdown signal S4 from the AND circuit 4, the controller 5 maintains the first switch 21 and the second switch 22 in a shutdown state and the battery switch 24 in a conductive state. Thereafter, the controller 5 determines whether the first system voltage and the second system voltage remain below the ground fault threshold or have recovered to above the ground fault threshold. The controller 5 determines whether a system that has recovered to above the ground fault threshold is a normal system, and determines whether a system that remains below the ground fault threshold is a ground fault system.

[0057] When the voltage sensor 6 is used to perform the pre-shutdown and the main determination, only one voltage sensor is required, which leads to cost reduction, but the main determination process requires alternately turning on and off the first switch 21 and the second switch 22 to determine whether the system has a ground fault, which takes some time. In contrast, when the main determination is performed using the first system voltage and the second system voltage, although the additional voltage sensors increase costs, the time required for the main determination can be reduced because the ground fault states of the first system 110 and the second system 120 can be determined in parallel. Which determination method to use can be determined based on the required specifications.

[0058] In the following description, the explanation will be continued by taking as an example a configuration in which the voltage sensor 6 is used to perform the pre-shutdown and the main determination.

[0059] [4. Power supply control device diagnostic operation] When the system voltage V1 falls below the lower limit (ground fault threshold) of the system voltage V1 under normal conditions when no ground fault has occurred, the power supply control device 1 must immediately pre-shut off the disconnecting mechanism 2 to prevent discharge from the main power supply 10 or the backup power supply 20 to the ground fault point. For example, the power supply control device 1 must pre-shut off the disconnecting mechanism 2 within a required response time of 100 μs. For this reason, the controller 5 diagnoses whether the response operation of the circuit that shuts off the disconnecting mechanism 2 meets the required response time. The controller 5 performs this diagnosis at a predetermined timing while the vehicle is not running, for example, immediately after the ignition is turned on or immediately after the ignition is turned off.

[0060] In normal mode where no ground fault occurs, the controller 5 outputs a PWM (Pulse Width Modulation) signal as the abnormality threshold Vth to the comparator 31. The abnormality threshold Vth increases as the duty ratio of the PWM signal increases, and decreases as the duty ratio decreases.

[0061] 5, in the diagnostic mode, the controller 5 turns on the bypass switch 23 from the normal state. Thereafter, the controller 5 controls the abnormality threshold Vth to be equal to or greater than the value of the system voltage V1, and measures the time required from when the comparator 31 outputs the abnormality detection signal S1 until the cutoff mechanism 2 cuts off the connection between the first system 110 and the second system 120. In this case, the controller 5 receives the abnormality detection signal S1 output by the comparator 31 as an input.

[0062] In addition, when the controller 5 is configured to input a disconnection signal S2 from the latch circuit 32, it measures the time required from when the latch circuit 32 outputs the disconnection signal S2 until the disconnection mechanism 2 disconnects the connection between the first system 110 and the second system 120.

[0063] At this time, the controller 5 does not intentionally reduce the system voltage V1 to below the abnormal threshold Vth to recreate a ground fault state, but instead changes the abnormal threshold Vth to be equal to or greater than the system voltage V1 to recreate a ground fault state and shut off the circuit breaking mechanism 2.

[0064] That is, in the diagnosis mode, the controller 5 reproduces a ground fault state by adjusting the abnormality threshold Vth without manipulating the system voltage V1, and causes the breaking mechanism 2 to break. This allows the controller 5 to prevent the power supply to the first load 101 and the second load 102 from being interrupted in the diagnosis mode, and therefore allows the diagnosis to be performed without adversely affecting the first load 101 and the second load 102.

[0065] When the abnormality threshold Vth becomes equal to or greater than the system voltage V1, the comparator 31 outputs an abnormality detection signal S1 and the AND circuit 4 outputs a shutdown signal S4, causing the power supply control device 1 to shut off the shutdown mechanism 2 and turn on the battery switch 24, as shown in FIG. 6.

[0066] When the first switch 21 and the second switch 22 are turned off, the voltage sensor 6 stops detecting voltage, that is, the detected voltage becomes 0 [V]. Therefore, the controller 5 can obtain, for example, the timing when the voltage input from the voltage sensor 6 becomes equal to or lower than the abnormal threshold value Vth as the timing when the cutoff mechanism 2 has cut off. Note that the bypass switch 23 is maintained in the on state.

[0067] At this time, the controller 5 keeps the bypass switch 23 in the OFF state in the normal mode, and keeps the bypass switch 23 in the ON state in the diagnosis mode. This allows the controller 5 to continue supplying power from the main power supply 10 to the first load 101 and the second load 102 via the bypass switch 23, even if the timing at which the cutting mechanism 2 is cut off is earlier than the timing at which the battery switch 24 is turned on. Therefore, the controller 5 can perform diagnosis without interrupting the power supply from the main power supply 10 to the second system 120.

[0068] Then, the controller 5 measures the time required from when the abnormality detection signal S1 or the shutdown signal S2 is input until the shutdown mechanism 2 performs shutdown. Specifically, the controller 5 measures the time required from when the abnormality detection signal S1 or the shutdown signal S2 is input until the voltage detected by the voltage sensor 6 becomes equal to or lower than the abnormality threshold value Vth.

[0069] The voltage detected by the voltage sensor 6 becomes equal to or lower than the abnormality threshold Vth when both the first switch 21 and the second switch 22 are turned off, that is, when the shutoff mechanism 2 is completely shut off. Therefore, the controller 5 can accurately measure the time required from when the abnormality detection signal S1 or the shutoff signal S2 is input until the shutoff mechanism 2 is shut off.

[0070] As a result, if the required time is longer than a specified time (for example, 100 μs, the response request time), the controller 5 switches the bypass switch 34 of the bypass circuit 33 from off to on, thereby switching the bypass circuit 33 from disabled to enabled. Then, the controller 5 causes the comparator 31 to output an abnormality detection signal S1 to the cutoff mechanism 2 via the bypass circuit 33, causing the cutoff mechanism 2 to cut off.

[0071] In this way, if the time required from when the abnormality detection signal S1 or the shutdown signal S2 is output in the diagnostic mode until the connection between the first system 110 and the second system 120 is shut off is longer than the specified time, the power supply control device 1 changes the bypass circuit 33 from disabled to enabled.

[0072] As a result, if the response times of the latch circuit 32 or the AND circuit 4 become longer due to aging, the power supply control device 1 can shut off the shutoff mechanism 2 by outputting the abnormality detection signal S1 directly from the comparator 31 to the shutoff mechanism 2 without going through the latch circuit 32. Therefore, even if the response times of the latch circuit 32 or the AND circuit 4 become longer due to aging, the power supply control device 1 can shorten the time from the output of the abnormality detection signal S1 to the shutoff of the shutoff mechanism 2, and therefore can meet the required response time.

[0073] Furthermore, by enabling the bypass circuit 33 and outputting the abnormality detection signal S1 directly from the comparator 31 to the shutdown mechanism 2, the power supply control device 1 can shorten the propagation path of the abnormality detection signal S1 compared to when the signal passes through the latch circuit 32 and the AND circuit 4. This allows the power supply control device 1 to shorten the time required from the output of the abnormality detection signal S1 by the comparator 31 to the shutdown of the shutdown mechanism 2.

[0074] [5. Processing performed by the controller] Next, a process executed by the controller 5 will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of a process executed by the controller 5 according to the embodiment. For example, when the ignition switch of the vehicle is turned on, the controller 5 transitions to a diagnostic mode and executes the diagnostic process shown in Fig. 7.

[0075] The controller 5 may be configured to transition to the diagnostic mode when the ignition switch of the vehicle is turned off, and to execute the diagnostic processing shown in Fig. 7. The controller 5 may be configured to transition to the diagnostic mode once every few months or after every few trips, and to execute the processing shown in Fig. 7.

[0076] First, the controller 5 transmits a control signal (shutdown enable signal) S3 to the AND circuit 4 (step S101). Next, the controller 5 turns on the shutdown mechanism 2, turns off the battery switch 24 (step S102), turns on the bypass switch 23, and turns off the bypass switch 34 (step S103).

[0077] Next, the controller 5 starts adjusting the abnormality threshold Vth (step S104). Specifically, the controller 5 increases the abnormality threshold Vth by a predetermined amount. Thereafter, the controller 5 determines whether or not the disconnection of the disconnection mechanism 2 has been completed (step S105). When the controller 5 detects that the system voltage V1 output by the voltage sensor 6 has become equal to or lower than the ground fault threshold, the controller 5 determines that the disconnection of the disconnection mechanism 2 has been completed. When the controller 5 determines that the disconnection of the disconnection mechanism 2 has not been completed (step S105, No), the controller 5 proceeds to step S104.

[0078] Furthermore, if the controller 5 determines that the shutoff mechanism 2 has been shut off (step S105, Yes), it measures the time required from the output of the abnormality detection signal S1 or the shutoff signal S2 until the shutoff mechanism 2 has been shut off (step S106).

[0079] Next, the controller 5 determines whether the measured required time is equal to or less than a specified time (for example, 100 μs, which is the required response time) (step S107). If the controller 5 determines that the required time is equal to or less than the specified time (step S107, Yes), the controller 5 diagnoses the latch circuit 32 and the AND circuit 4 as normal (step S108) and ends the diagnosis process.

[0080] Furthermore, if the controller 5 determines that the required time is not equal to or less than the specified time (step S107, No), that is, that the required time is longer than the specified time, it turns the bypass switch 34 of the bypass circuit 33 from off to on (step S109). Thereafter, the controller 5 stores the bypass switch on as the initial setting information of the bypass switch 34 (step S110) and ends the diagnostic processing. Note that, after the diagnostic processing ends, the controller 5 transitions to a control mode and performs power supply failure monitoring and fail-safe control. The processing in the control mode will be omitted.

[0081] Thereafter, when the vehicle ignition switch is turned on, the controller 5 controls the bypass switch 34 of the bypass circuit 33 in the control mode according to the initial setting information. If the controller 5 has stored the bypass switch off as the initial setting information, the controller 5 turns off the bypass switch 34 and starts controlling the power supply control device 1. If the controller 5 has stored the bypass switch on as the initial setting information, the controller 5 turns on the bypass switch 34 and starts controlling the power supply control device 1.

[0082] In this way, when the controller 5 determines in the diagnostic mode that the time required from the input of the abnormality detection signal S1 or the shutoff signal S2 until the shutoff mechanism 2 shuts off is longer than the specified time, the controller 5 stores a setting to turn on the bypass switch 34 as initial setting information. Then, the controller 5 controls the bypass switch 34 in accordance with the initial setting information the next time it is started up.

[0083] This eliminates the need for the controller 5 to diagnose, each time it is started, whether the time required from the input of the abnormality detection signal S1 or the shutdown signal S2 until the shutdown mechanism 2 shuts off satisfies the specified time, which is the required response time, thereby reducing the processing load.

[0084] [6. Notes] As an appendix, the features of the present invention are as follows. (1) a cutoff mechanism that cuts off a connection between a first system that supplies power from the main power source to the load and a second system that supplies power from the backup power source to the load; a comparator that compares a system voltage, which is a voltage of the first system or the second system, with an abnormality threshold, and outputs an abnormality detection signal when the system voltage becomes equal to or lower than the abnormality threshold; a latch circuit that latches the abnormality detection signal and outputs a cutoff signal to cause the cutoff mechanism to cut off the connection between the first system and the second system; a bypass circuit that bypasses the latch circuit; In a diagnostic mode, the system voltage is controlled to be equal to or lower than the abnormality threshold value, and a required time is measured from when the abnormality detection signal or the disconnection signal is output until the connection between the first system and the second system is disconnected; a controller that switches the bypass circuit from disabled to enabled if the required time is longer than a specified time, and outputs the abnormality detection signal from the comparator to the cutoff mechanism via the bypass circuit; A power supply control device comprising: (2) the bypass circuit has a switch; The controller If it is determined in the diagnostic mode that the required time is longer than the specified time, the switch is turned on to change the bypass circuit from disabled to enabled. The power supply control device according to (1) above. (3) The controller If it is determined in the diagnostic mode that the required time is longer than the specified time, the setting for turning on the switch is stored as initial setting information, and the switch is controlled in accordance with the initial setting information at the next startup. The power supply control device according to (2) above. (4) The blocking mechanism includes: a first switch and a second switch connected in series; a voltage sensor that detects a voltage at a connection point between the first switch and the second switch; and The controller The time from when the output of the abnormality detection signal or the interruption signal is detected until the voltage detected by the voltage sensor falls below the abnormality threshold is measured as the required time. The power supply control device according to any one of (1) to (3). (5) The controller In the diagnosis mode, the abnormality threshold is changed so as to be equal to or greater than the value of the grid voltage, and the grid voltage is controlled so as to be equal to or less than the abnormality threshold. A power supply control device according to any one of (1) to (4). (6) a gate circuit that enables or disables the cutoff signal input from the latch circuit in response to a control signal input from the controller; The bypass circuit is Bypassing the latch circuit and the gate circuit A power supply control device according to any one of (1) to (5). (7) a cutoff mechanism that cuts off a connection between a first system that supplies power from the main power source to the load and a second system that supplies power from the backup power source to the load; a comparator that compares a system voltage, which is a voltage of the first system or the second system, with an abnormality threshold, and outputs an abnormality detection signal when the system voltage becomes equal to or lower than the abnormality threshold; a latch circuit that latches the abnormality detection signal and outputs a cutoff signal to cause the cutoff mechanism to cut off the connection between the first system and the second system; a bypass circuit that bypasses the latch circuit; A controller of a power supply control device comprising: In a diagnostic mode, the system voltage is controlled to be equal to or lower than the abnormality threshold value, and a required time from when the abnormality detection signal or the disconnection signal is output until the connection between the first system and the second system is disconnected is measured. If the required time is longer than a specified time, the bypass circuit is changed from disabled to enabled, and the abnormality detection signal is output from the comparator to the cutoff mechanism via the bypass circuit. Power control program.

[0085] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0086] 1 Power supply control device 2. Shut-off mechanism 3. Detector 4 AND Circuit 5 Controller 6 Voltage Sensor 10 Main power supply 20 Backup power supply 21 First Switch 22 Second Switch 23 Bypass switch 24 Battery switch 31 Comparator 32 Latch circuit 33 Bypass circuit 34 Bypass switch 101 1st load 102 2nd load 110 1st system 120 2nd system 200 Earth fault S1 Abnormality detection signal S2 Shutdown signal S3 control signal V1 System voltage Vth Abnormal threshold

Claims

1. a disconnection mechanism that disconnects a first system that supplies power from the main power supply to the load and a second system that supplies power from the backup power supply to the load; a comparator that compares a system voltage, which is a voltage of the first system or the second system, with an abnormality threshold, and outputs an abnormality detection signal when the system voltage becomes equal to or lower than the abnormality threshold; a latch circuit that latches the abnormality detection signal and outputs a cutoff signal to cause the cutoff mechanism to cut off the connection between the first system and the second system; a bypass circuit that bypasses the latch circuit; In a diagnostic mode, the system voltage is controlled to be equal to or lower than the abnormality threshold value, and a required time is measured from when the abnormality detection signal or the disconnection signal is output until the connection between the first system and the second system is disconnected; a controller that switches the bypass circuit from disabled to enabled if the required time is longer than a specified time, and outputs the abnormality detection signal from the comparator to the cutoff mechanism via the bypass circuit; A power supply control device comprising:

2. the bypass circuit has a switch; The controller If it is determined in the diagnostic mode that the required time is longer than the specified time, the switch is turned on to change the bypass circuit from disabled to enabled. The power supply control device according to claim 1 .

3. The controller If it is determined in the diagnostic mode that the required time is longer than the specified time, the setting for turning on the switch is stored as initial setting information, and the switch is controlled in accordance with the initial setting information at the next startup. The power supply control device according to claim 2 .

4. The blocking mechanism includes: a first switch and a second switch connected in series; a voltage sensor that detects a voltage at a connection point between the first switch and the second switch; and The controller The time from when the output of the abnormality detection signal or the interruption signal is detected until the voltage detected by the voltage sensor falls below the abnormality threshold is measured as the required time. The power supply control device according to claim 1 .

5. The controller In the diagnosis mode, the abnormality threshold is changed so as to be equal to or greater than the value of the grid voltage, and the grid voltage is controlled so as to be equal to or less than the abnormality threshold. The power supply control device according to claim 1 .

6. a gate circuit that enables or disables the cutoff signal input from the latch circuit in response to a control signal input from the controller; The bypass circuit is Bypassing the latch circuit and the gate circuit The power supply control device according to claim 1 .

7. a disconnection mechanism that disconnects a first system that supplies power from the main power supply to the load and a second system that supplies power from the backup power supply to the load; a comparator that compares a system voltage, which is a voltage of the first system or the second system, with an abnormality threshold, and outputs an abnormality detection signal when the system voltage becomes equal to or lower than the abnormality threshold; a latch circuit that latches the abnormality detection signal and outputs a cutoff signal to cause the cutoff mechanism to cut off the connection between the first system and the second system; a bypass circuit that bypasses the latch circuit; A controller of a power supply control device comprising: In a diagnostic mode, the system voltage is controlled to be equal to or lower than the abnormality threshold value, and a required time from when the abnormality detection signal or the disconnection signal is output until the connection between the first system and the second system is disconnected is measured. If the required time is longer than a specified time, the bypass circuit is changed from disabled to enabled, and the abnormality detection signal is output from the comparator to the cutoff mechanism via the bypass circuit. Power control program.

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