Vehicle power supply

Abstract

This technology provides a way to prevent power supply shortages to specific loads. [Solution] The vehicle power supply unit 20 includes a control unit 35. When the first detection target, which is at least one of the voltage value of the first conductive path 15 and the current value flowing through the first conductive path 15, falls below a first threshold V1, the control unit 35 controls the switching unit (e.g., third voltage conversion unit 23) to a second state and switches all or part of the loads (e.g., first load 13, second load 14) of the plurality of first loads 12, 13 and at least one second load 14, excluding a specific first load (e.g., first load 12), to a power-saving state.

Description

Technical Field

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[0001] The present disclosure relates to a vehicle power supply device.

Background Art

[0002] Patent Document 1 discloses a vehicle power supply device. This vehicle power supply device includes a first voltage conversion unit that supplies power to a first load via a second conductive path, and a second voltage conversion unit that supplies power to a second load via a third conductive path. At least one switch unit is provided between the second conductive path and the third conductive path. In the case of a predetermined abnormal state, the switch unit is controlled to be in an on state, and power supply from the third conductive path side to the second conductive path side is permitted.

Prior Art Documents

Patent Documents

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration of Patent Document 1, when the switch unit is controlled to be in an on state, the power supply from the second voltage conversion unit is distributed to the second load and the first load. Therefore, there is a possibility that sufficient power may not be supplied to the first load.

[0005] An object of the present disclosure is to provide a technology in which power supply shortage to a specific load is unlikely to occur.

Means for Solving the Problems

[0006] The vehicle power supply device of the present disclosure is a vehicle power supply device included in an in - vehicle system including a first power storage unit, a plurality of first loads to which power from the first power storage unit is supplied via a power path, and at least one second load to which power from the first power storage unit is supplied via the power path, A first conductive path is provided between the power path and the plurality of first loads, A second conductive path is provided between the power path and the at least one second load, A first voltage conversion unit is provided between the power line and the first conductive line, A second voltage conversion unit is provided between the power line and the second conductive line, A switching section provided between the first conductive path and the second conductive path, The system comprises a control unit that controls the first voltage conversion unit, the second voltage conversion unit, and the switching unit, The first voltage conversion unit performs a first conversion operation in which it converts the voltage applied to the power path and applies it to the first conductive path. The second voltage conversion unit performs a second conversion operation in which it converts the voltage applied to the power path and applies it to the second conductive path. The switching unit switches between a first state in which the power supply from the second conductive path to the first conductive path is interrupted, and a second state in which the power supply from the second conductive path to the first conductive path is permitted. All or part of the plurality of first loads and at least one of the second loads, excluding at least one specific first load, have a communication function with the control unit and switch between an activated state and a power-saving state with lower power consumption than the activated state based on a signal output from the control unit. The control unit controls the switching unit to the second state when the first detection target, which is at least one of the voltage value of the first conductive path and the current value flowing through the first conductive path, falls below the first threshold, and switches all or part of the loads among the plurality of first loads and the at least one second load, excluding the specific first load, to the power-saving state. [Effects of the Invention]

[0007] The technology described herein makes it less likely for power supply shortages to specific loads to occur. [Brief explanation of the drawing]

[0008] [Figure 1]Figure 1 is a schematic diagram showing the in-vehicle system of the first embodiment. [Figure 2] Figure 2 is a conceptual diagram illustrating the normal operation of the in-vehicle system of the first embodiment. [Figure 3] Figure 3 is a conceptual diagram illustrating the operation of the in-vehicle system of the first embodiment in the first failure state. [Figure 4] Figure 4 is a conceptual diagram illustrating the operation of the in-vehicle system of the first embodiment in the second failure state. [Figure 5] Figure 5 is a timing chart showing the operation when the first failure state occurs in the in-vehicle system of the first embodiment. [Figure 6] Figure 6 is a timing chart showing the operation when the second failure state occurs in the in-vehicle system of the first embodiment. [Figure 7] Figure 7 is a timing chart showing the operation when the third failure state occurs in the in-vehicle system of the first embodiment. [Figure 8] Figure 8 is a schematic diagram showing the in-vehicle system of the second embodiment. [Figure 9] Figure 9 is a conceptual diagram illustrating the normal operation of the in-vehicle system of the second embodiment. [Figure 10] Figure 10 is a conceptual diagram illustrating the operation of the in-vehicle system of the second embodiment in the first failure state. [Figure 11] Figure 11 is a conceptual diagram illustrating the operation of the in-vehicle system of the second embodiment in the second failure state. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0010] A vehicle power supply device included in an in-vehicle system including a first power storage unit, a plurality of first loads to which power from the first power storage unit is supplied via a power path, and at least one second load to which power from the first power storage unit is supplied via the power path, comprising: A first conductive path provided between the power path and the plurality of first loads; A second conductive path provided between the power path and the at least one second load; A first voltage conversion unit provided between the power path and the first conductive path; A second voltage conversion unit provided between the power path and the second conductive path; A switching unit provided between the first conductive path and the second conductive path; A control unit that controls the first voltage conversion unit, the second voltage conversion unit, and the switching unit, The first voltage conversion unit performs a first conversion operation of converting a voltage applied to the power path and applying it to the first conductive path. The second voltage conversion unit performs a second conversion operation of converting a voltage applied to the power path and applying it to the second conductive path. The switching unit switches between a first state in which power supply from the second conductive path side to the first conductive path side is blocked and a second state in which power supply from the second conductive path side to the first conductive path side is permitted. All or part of the loads excluding at least a specific one of the plurality of first loads and the at least one second load have a communication function with the control unit and switch between an activation state and a power saving state with lower power consumption than the activation state based on a signal output from the control unit. When at least one of the voltage value of the first conductive path and the current value flowing through the first conductive path, which is a first detection target, becomes equal to or less than a first threshold value, the control unit controls the switching unit to the second state and switches all or part of the loads excluding the specific first load among the plurality of first loads and the at least one second load to the power saving state. Vehicle power supply device.

[0011] The above-described vehicle power supply unit supplies power from the first voltage conversion unit to the first load via the first conductive path, and supplies power from the second voltage conversion unit to the second load via the second conductive path. When the first detection target falls below the first threshold, the vehicle power supply unit controls the switching unit to the second state, switching all or some of the loads except the specific first load to a power-saving state. This allows power to be supplied from the second voltage conversion unit to the specific first load while suppressing power supply to all or some of the loads except the specific first load. Therefore, even if the output voltage from the first voltage conversion unit decreases and power is supplied from the second voltage conversion unit to the specific first load, a power shortage to the specific first load is less likely to occur.

[0012] [2] The switching unit switches between a third state in which the power supply from the first conductive path to the second conductive path is interrupted, and a fourth state in which the power supply from the first conductive path to the second conductive path is permitted. All or part of the plurality of first loads and at least one of the second loads, excluding at least one specific second load, have a communication function with the control unit and switch between the activated state and the power-saving state based on a signal output from the control unit. When the control unit detects that the second detection target, which is at least one of the voltage value of the second conductive path and the current value flowing through the second conductive path, falls below the second threshold, it controls the switching unit to the fourth state and switches all or part of the loads, excluding the specific second load, from the plurality of first loads and at least one of the second loads, to the power-saving state. The vehicle power supply device described in [1].

[0013] The above-described vehicle power supply unit controls the switching unit to the fourth state when the second detection target falls below the second threshold, switching all or some of the loads except the specific second load to a power-saving state. This allows power to be supplied from the first voltage conversion unit to the specific second load while suppressing power supply to all or some of the loads except the specific second load. Therefore, even if the output voltage from the second voltage conversion unit decreases and power is supplied from the first voltage conversion unit to the specific second load, a power supply shortage to the specific second load is less likely to occur.

[0014] [3] The switching unit controls the switching unit to the first state and the third state when the first detection target exceeds an overvoltage threshold greater than the first threshold. The vehicle power supply device described in [2].

[0015] The above-mentioned vehicle power supply device can interrupt the flow of current between the first conductive path and the second conductive path by controlling the switching unit to a first state and a third state when the first detected target exceeds an overvoltage threshold.

[0016] [4] The control unit stores a table that defines the priority of each load in advance and determines the load to switch to the power-saving state based on the table. A vehicle power supply device as described in any of [1] to [3].

[0017] The above-mentioned vehicle power supply unit can determine which loads to switch to a power-saving state based on predetermined priorities.

[0018] [5] The second energy storage unit is electrically connected to the first conductive path. A vehicle power supply device as described in any of [1] to [3].

[0019] The above-described vehicle power supply device can suppress a sharp drop in the voltage of the first conductive path even when the output voltage of the first voltage conversion unit drops sharply, thanks to the power supplied from the second energy storage unit.

[0020] [6] The switching unit has a third voltage conversion unit, The third voltage conversion unit performs a third conversion operation that converts the voltage input from the second conductive path and outputs it to the first conductive path. The switching unit causes the third voltage conversion unit to perform the third conversion operation in the second state. A vehicle power supply device as described in any of [1] to [3].

[0021] The above-mentioned vehicle power supply unit can convert the voltage output from the second voltage conversion unit using the third voltage conversion unit and output it to the first conductive path.

[0022] [Details of the embodiments of this disclosure] 1. First Embodiment 1-1. Configuration of In-Vehicle System 1 The in-vehicle system 1 shown in Figure 1 comprises a first energy storage unit 10, a power line 11, a plurality of first loads 12, 13, a second load 14, a first conductive line 15, a second conductive line 16, a second energy storage unit 17, a communication bus 18, and a vehicle power supply device 20.

[0023] The first energy storage unit 10 is composed of, for example, a battery. The power line 11 is electrically connected to the first energy storage unit 10. Power from the first energy storage unit 10 is supplied to a plurality of first loads 12, 13 via the power line 11. Power from the first energy storage unit 10 is supplied to the second load 14 via the power line 11.

[0024] The first conductive path 15 is provided between the power path 11 and the multiple first loads 12 and 13. The second conductive path 16 is provided between the power path 11 and the second load 14. The second energy storage unit 17 is electrically connected to the first conductive path 15. The second energy storage unit 17 is composed of, for example, a battery or a capacitor.

[0025] Each load 12, 13, and 14 is, for example, an ECU (Electronic Control Unit). Each load 12, 13, and 14 switches between a power-up state and a power-saving state that consumes less power than the power-up state. Each load 12, 13, and 14 has, for example, a CPU (Central Processing Unit). Each load 12, 13, and 14 enters the power-up state when the CPU enters the power-up state and enters the power-saving state when the CPU enters the sleep state. Each load 12, 13, and 14 has a communication function. Each load 12, 13, and 14 has a communication unit 12A, 13A, and 14A. The communication units 12A, 13A, and 14A are communication interfaces for communication via the communication bus 18, and are, for example, transceivers.

[0026] 1-2. Configuration of the vehicle power supply unit 20 The vehicle power supply unit 20 includes a first voltage conversion unit 21, a second voltage conversion unit 22, a third voltage conversion unit 23, a first detection unit 24, a second detection unit 25, and a control unit 35.

[0027] The first voltage conversion unit 21 is provided between the power line 11 and the first conductive line 15. The first voltage conversion unit 21 performs a first conversion operation in which it converts the voltage applied to the power line 11 and applies it to the first conductive line 15. The first voltage conversion unit 21 is configured, for example, by a DC-DC converter.

[0028] The second voltage conversion unit 22 is provided between the power line 11 and the second conductive line 16. The second voltage conversion unit 22 performs a second conversion operation in which it converts the voltage applied to the power line 11 and applies it to the second conductive line 16. The second voltage conversion unit 22 is configured, for example, by a DC-DC converter.

[0029] The third voltage conversion unit 23 corresponds to an example of a switching unit. The third voltage conversion unit 23 is provided between the first conductive path 15 and the second conductive path 16. The third voltage conversion unit 23 performs a third conversion operation, converting the voltage input from the second conductive path 16 side and outputting it to the first conductive path 15 side. The third voltage conversion unit 23 performs a fourth conversion operation, converting the voltage input from the first conductive path 15 side and outputting it to the second conductive path 16 side. The third voltage conversion unit 23 is configured, for example, by a DC-DC converter. By stopping its operation, the third voltage conversion unit 23 enters a first state in which it cuts off the power supply from the second conductive path 16 side to the first conductive path 15 side. By performing the third conversion operation, the third voltage conversion unit 23 enters a second state in which it allows the power supply from the second conductive path 16 side to the first conductive path 15 side. The third voltage conversion unit 23 enters a third state by stopping its operation, thereby cutting off the power supply from the first conductive path 15 to the second conductive path 16. The third voltage conversion unit 23 then enters a fourth state by performing a fourth conversion operation, thereby allowing the power supply from the first conductive path 15 to the second conductive path 16.

[0030] The first detection unit 24 detects the voltage value of the first conductive path 15 as the first detection target. Alternatively, the first detection unit 24 may detect the current value flowing through the first conductive path 15 as the first detection target. A signal indicating the detection result of the first detection unit 24 is input to the control unit 35. The second detection unit 25 detects the voltage value of the second conductive path 16 as the second detection target. Alternatively, the second detection unit 25 may detect the current value flowing through the second conductive path 16 as the second detection target. A signal indicating the detection result of the second detection unit 25 is input to the control unit 35.

[0031] The control unit 35 is comprised of, for example, a microcomputer. The control unit 35 includes a CPU, memory, drive circuits, etc. The control unit 35 is realized, for example, by the CPU executing a computer program stored in memory.

[0032] The control unit 35 has a communication unit 35A. The communication unit 35A is a communication interface for communication via the communication bus 18, and is, for example, a transceiver. The control unit 35 can communicate with loads 12, 13, and 14 via the communication bus 18. The control unit 35 controls each load 12, 13, and 14 to an activated state individually by giving an activation instruction signal, and controls each load 12, 13, and 14 to a power-saving state individually by giving a sleep instruction signal.

[0033] 1-3. Operation of the vehicle power supply unit 20 The control unit 35 controls the first voltage conversion unit 21, the second voltage conversion unit 22, and the third voltage conversion unit 23.

[0034] In normal operation, the control unit 35 controls loads 12, 13, and 14 to an activated state, causing the first voltage conversion unit 21 to perform a first conversion operation and the second voltage conversion unit 22 to perform a second conversion operation. As a result, as shown in Figure 2, the output voltage of the first voltage conversion unit 21 is supplied to the first loads 12 and 13, and the output voltage of the second voltage conversion unit 22 is supplied to the second load 14.

[0035] The control unit 35 causes the first voltage conversion unit 21 to perform a first conversion operation so that the output voltage becomes the first target voltage. In this embodiment, the first target voltage is 48V. The control unit 35 causes the second voltage conversion unit 22 to perform a second conversion operation so that the output voltage becomes the second target voltage. In this embodiment, the second target voltage is a smaller value than the first target voltage, specifically 12V.

[0036] The normal state is a state that is not in a lost state, and is the state before it is determined to be in a lost state. Lost states include the first lost state, the second lost state, and the third lost state.

[0037] The first failure state is a state in which the output of the first voltage conversion unit 21 has stopped. The control unit 35 determines that the first failure state is occurring when the first detection target detected by the first detection unit 24 falls below the first threshold V1. The first threshold V1 is 0V or greater and is smaller than the first target voltage.

[0038] The second failure state is a state in which the output of the second voltage conversion unit 22 has stopped. The control unit 35 determines that the second failure state is occurring when the second detection target detected by the second detection unit 25 falls below the second threshold V2. The second threshold V2 is 0V or greater and is smaller than the second target voltage.

[0039] The third failure state is a state in which the third voltage conversion unit 23 stops while outputting an overvoltage. The control unit 35 determines that the third failure state is occurring when the first detection target exceeds the overvoltage threshold V5. The overvoltage threshold V5 is a value greater than the first target voltage.

[0040] Under normal conditions, the control unit 35 causes the third voltage conversion unit 23 to perform a sharing operation. This sharing operation involves sharing the output voltage of the second voltage conversion unit 22 with the first conductive path 15 when the output voltage of the first voltage conversion unit 21 is temporarily insufficient, and sharing the output voltage of the first voltage conversion unit 21 with the second conductive path 16 when the output voltage of the second voltage conversion unit 22 is temporarily insufficient. When the first detection target is greater than the third threshold V3 and the second detection target is greater than the fourth threshold V4, the control unit 35 stops the third voltage conversion unit 23 and cuts off the current flow between the first conductive path 15 and the second conductive path 16. The third threshold V3 is a value that is less than the first target voltage and greater than the first threshold V1. The fourth threshold V4 is a value that is less than the second target voltage and greater than the second threshold V2.

[0041] If the first detection target is below the third threshold V3 and greater than the first threshold V1, the control unit 35 causes the third voltage conversion unit 23 to perform a third conversion operation so that the output voltage becomes the first target voltage. If the second detection target is below the fourth threshold V4 and greater than the second threshold V2, the control unit 35 causes the third voltage conversion unit 23 to perform a fourth conversion operation so that the output voltage becomes the second target voltage.

[0042] When the first detection target falls below the first threshold V1 under normal conditions, the control unit 35 causes the third voltage conversion unit 23 to perform a third conversion operation so that the output voltage becomes the first target voltage, and while maintaining the specific first load (first load 12 in this embodiment) in the activated state, it switches all loads 13 and 14 of the multiple first loads 12 and 13 and second loads 14 except for the specific first load 12 to a power-saving state. As a result, as shown in Figure 3, the power supply to the first load 13 and the second load 14 is suppressed, and the output voltage of the second voltage conversion unit 22 is converted by the third voltage conversion unit 23 and supplied to the specific first load 12.

[0043] A specific first load may be fixed in advance. The control unit 35 may store a table that defines the priority of loads 12, 13, and 14 in advance and determine a specific first load based on this table. For example, the control unit 35 may determine the first load with the highest priority as the specific first load. The control unit 35 may store multiple tables. Multiple tables may be provided corresponding to the state of the vehicle. The state of the vehicle may be, for example, whether the vehicle is parked or driving, whether it is driving straight or turning, whether it is driving uphill or on a flat road, etc. The control unit 35 may select a table according to the state of the vehicle and determine a specific first load based on the selected table.

[0044] The control unit 35 may switch only some of the loads among the multiple first loads 12, 13 and second loads 14, excluding a specific first load 12, to a power-saving state. For example, the control unit 35 may switch only loads with relatively low priority to a power-saving state based on the table above. The number of loads to be switched to a power-saving state may be determined, for example, based on the remaining capacity of the first energy storage unit 10.

[0045] When the second detection target falls below the second threshold V2 under normal conditions, the control unit 35 causes the third voltage conversion unit 23 to perform a fourth conversion operation so that the output voltage becomes the second target voltage, and switches the first loads 12 and 13 to a power-saving state while keeping the second load 14 in the activated state. As a result, as shown in Figure 4, the power supply to the first loads 12 and 13 is cut off, and the output voltage of the first voltage conversion unit 21 is converted by the third voltage conversion unit 23 and supplied to the second load 14.

[0046] In the normal state, if the first detection target exceeds the overvoltage threshold V5, the control unit 35 switches the loads 12, 13, and 14 to a power-saving state and stops the third voltage conversion unit 23 to interrupt the current flow between the first conductive path 15 and the second conductive path 16. This suppresses the current supplied to the loads 12, 13, and 14 and prevents the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

[0047] Figure 5 shows a timing chart illustrating an example of operation when the first failure state occurs. At timing T1 in Figure 5, the system is in a normal state. In other words, the control unit 35 causes the first voltage conversion unit 21 to perform the first conversion operation, the second voltage conversion unit 22 to perform the second conversion operation, and the third voltage conversion unit 23 to perform the bridging operation, thereby controlling the loads 12, 13, and 14 to be in an activated state. As a result, the voltage of the first conductive path 15 becomes the first target voltage (48V), and the voltage of the second conductive path 16 becomes the second target voltage (12V).

[0048] At timing T2, the first voltage conversion unit 21 fails and its output stops, causing the voltage across the first conductive path 15 to drop. At timing T3, when the control unit 35 determines that the voltage across the first conductive path 15 has fallen below the first threshold V1, it maintains the first load 12 in the activated state while switching the first load 13 and the second load 14 to a power-saving state and causing the third voltage conversion unit 23 to perform the third conversion operation. As a result, the voltage across the first conductive path 15 returns to the first target voltage.

[0049] Figure 6 shows a timing chart illustrating an example of operation when the second loss state occurs. At timing T11 in Figure 6, the system is in the normal state.

[0050] At timing T12, the second voltage conversion unit 22 fails and its output stops, causing the voltage across the second conductive path 16 to drop. At timing T13, when the control unit 35 determines that the voltage across the second conductive path 16 has fallen below the second threshold V2, it maintains the second load 14 in the activated state while switching the first loads 12 and 13 to a power-saving state and causing the third voltage conversion unit 23 to perform the fourth conversion operation. As a result, the voltage across the second conductive path 16 returns to the second target voltage.

[0051] Figure 7 shows a timing chart illustrating an example of operation in the third lost state. At timing T21 in Figure 7, the system is in the normal state.

[0052] At timing T22, if the first voltage conversion unit 21 fails and outputs an overvoltage, the voltage of the first conductive path 15 rises. At timing T23, if the control unit 35 determines that the voltage of the first conductive path 15 exceeds the overvoltage threshold V5, it switches the loads 12, 13, and 14 to a power-saving state and stops the third voltage conversion unit 23. This suppresses the current supplied to the loads 12, 13, and 14 and prevents the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

[0053] 1-4. Effects of the First Embodiment The vehicle power supply unit 20 supplies power to the first loads 12 and 13 from the first voltage conversion unit 21 via the first conductive path 15, and supplies power to the second load 14 from the second voltage conversion unit 22 via the second conductive path 16. When the first detection target falls below the first threshold V1, the vehicle power supply unit 20 causes the third voltage conversion unit 23 to perform a third conversion operation, switching the first load 13 and the second load 14 to a power-saving state while maintaining the specific first load 12 in an activated state. This allows power to be supplied to the specific first load 12 from the second voltage conversion unit 22 while suppressing the power supply to the first load 13 and the second load 14. Therefore, even when the output voltage from the first voltage conversion unit 21 drops below the first threshold V1 and power is supplied to the specific first load 12 from the second voltage conversion unit 22, a power shortage to the specific first load 12 is less likely to occur.

[0054] When the second detection target falls below the second threshold V2, the vehicle power supply unit 20 causes the third voltage conversion unit 23 to perform a fourth conversion operation, switching the first loads 12 and 13 to a power-saving state while maintaining the second load 14 in the activated state. This allows power to be supplied from the first voltage conversion unit 21 to the second load 14 while suppressing the power supply to the first loads 12 and 13. Therefore, even when the output voltage from the second voltage conversion unit 22 drops below the second threshold V2 and power is supplied from the first voltage conversion unit 21 to the second load 14, a power shortage to the second load 14 is less likely to occur.

[0055] The vehicle power supply unit 20 can interrupt the flow of current between the first conductive path 15 and the second conductive path 16 by stopping the third voltage conversion unit 23 when the first detected object exceeds the overvoltage threshold V5.

[0056] The vehicle power supply unit 20 can determine which loads to switch to a power-saving state based on a priority set in a table.

[0057] Even if the output voltage of the first voltage conversion unit 21 drops sharply, the vehicle power supply unit 20 can suppress a sharp drop in the voltage of the first conductive path 15 by the power supplied from the second energy storage unit 17.

[0058] The vehicle power supply unit 20 can convert the voltage output from the second voltage conversion unit 22 using the third voltage conversion unit 23 and output it to the first conductive path 15. The vehicle power supply unit 20 can convert the voltage output from the first voltage conversion unit 21 using the third voltage conversion unit 23 and output it to the second conductive path 16.

[0059] 2. Second Embodiment In the first embodiment, a configuration in which the switching unit is a third voltage conversion unit was described. In contrast, in the second embodiment, an example in which the switching unit is configured by a changeover switch unit will be described. The same reference numerals are used for the same components as in the first embodiment, and detailed explanations are omitted.

[0060] The in-vehicle system 201 of the second embodiment includes a vehicle power supply unit 220 instead of the vehicle power supply unit 20 described in the first embodiment. The vehicle power supply unit 220 includes a switching unit 223 instead of the third voltage conversion unit 23 described in the first embodiment.

[0061] The switching unit 223 is provided between the first conductive path 15 and the second conductive path 16. The switching unit 223 has a first changeover switch unit 223A and a second changeover switch unit 223B. The first changeover switch unit 223A and the second changeover switch unit 223B are MOSFETs. The first changeover switch unit 223A and the second changeover switch unit 223B are connected in series between the first conductive path 15 and the second conductive path 16. The first changeover switch unit 223A and the second changeover switch unit 223B are connected in opposite directions to each other.

[0062] The first changeover switch unit 223A switches between an off state, which cuts off the power supply from the second conductive path 16 to the first conductive path 15, and an on state, which allows the power supply from the second conductive path 16 to the first conductive path 15. The second changeover switch unit 223B switches between an off state, which cuts off the power supply from the first conductive path 15 to the second conductive path 16, and an on state, which allows the power supply from the first conductive path 15 to the second conductive path 16.

[0063] The switching unit 223 enters a first state when the first changeover switch unit 223A is in the off state, a second state when the first changeover switch unit 223A is in the on state, a third state when the second changeover switch unit 223B is in the off state, and a fourth state when the second changeover switch unit 223B is in the on state.

[0064] In the second embodiment, the target voltage of the first voltage conversion unit 21 and the target voltage of the second voltage conversion unit 22 are the same, for example, 12V. In the normal state, the control unit 35 causes the third voltage conversion unit 23 to perform coordinated operation. Coordinated operation is the operation of making the first conductive path 15 and the second conductive path 16 conductive and bringing them to the same potential. Specifically, this is the operation of turning on the first changeover switch unit 223A and the second changeover switch unit 223B. In the normal state, as shown in Figure 9, power is supplied from the first voltage conversion unit 21 to the first loads 12 and 13, and power is supplied from the second voltage conversion unit 22 to the second load 14, and power can be exchanged between the first conductive path 15 and the second conductive path 16.

[0065] In the normal state, when the first detection target falls below the first threshold V1, the control unit 35 controls the first changeover switch unit 223A to the ON state and the second changeover switch unit 223B to the OFF state, thereby maintaining the specific first load 12 in the activated state, while switching all loads 13 and 14 of the multiple first loads 12, 13 and second loads 14 except for the specific first load 12 to a power-saving state. As a result, as shown in Figure 10, the power supply to the first load 13 and the second load 14 is suppressed, and the output voltage of the second voltage conversion unit 22 is supplied to the first load 12 via the switching unit 223.

[0066] A specific first load may be fixed in advance. The control unit 35 may determine a specific first load based on a table. The control unit 35 may switch only some of the multiple first loads 12, 13 and second loads 14, excluding the specific first load 12, to a power-saving state. For example, the control unit 35 may switch only loads with relatively low priority to a power-saving state based on the table. The number of loads to be switched to a power-saving state may be determined, for example, based on the remaining capacity of the first energy storage unit 10.

[0067] When the second detection target falls below the second threshold V2 under normal conditions, the control unit 35 controls the first changeover switch unit 223A to the off state and the second changeover switch unit 223B to the on state, thereby switching the multiple first loads 12 and 13 to a power-saving state while keeping the second load 14 in the activated state. As a result, as shown in Figure 11, the power supply to the first loads 12 and 13 is suppressed, and the output voltage of the first voltage conversion unit 21 is supplied to the second load 14 via the switching unit 223.

[0068] In the normal state, if the first detection target exceeds the overvoltage threshold V5, the control unit 35 switches the loads 12, 13, and 14 to a power-saving state and controls the first changeover switch unit 223A and the second changeover switch unit 223B to the off state, thereby interrupting the flow of current between the first conductive path 15 and the second conductive path 16. This suppresses the current supplied to the loads 12, 13, and 14 and prevents the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

[0069] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of the features of the embodiments described above or below is possible as long as it does not contradict each other. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. In addition, the embodiments described above may be modified as follows.

[0070] At least some of the loads, excluding a specific first load, should have communication capabilities and be able to switch between an active state and a power-saving state. In other words, the specific first load and some other loads do not need to have communication capabilities and do not need to switch between an active state and a power-saving state. Also, the specific first load and some other loads do not have to be ECUs.

[0071] The second load, like the first load, may be provided in multiple units. Each second load may have a communication function and may switch between an active state and a power-saving state. If the second voltage conversion unit fails, the control unit may switch all or part of the loads, excluding a specific second load, to a power-saving state.

[0072] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is indicated by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0073] 1…In-vehicle systems 10…First Energy Storage Unit 11…Power line 12…1st load 12A... Communications Department 13…1st load 13A... Communications Department 14…Second load 14A... Communications Department 15…First conductive path 16…Second conductive circuit 17…Second Energy Storage Unit 18... Communications bus 20... Vehicle power supply unit 21...First voltage conversion unit 22...Second voltage conversion section 23…Third voltage conversion section (switching section) 24...First detection unit 25...Second detection unit 35…Control Unit 35A…Communication Department 201... In-vehicle systems 220... Vehicle power supply unit 223... Switching section 223A...First changeover switch section 223B...Second changeover switch section V1…First threshold V2…Second threshold V3…Third threshold V4…Fourth threshold V5... Overvoltage threshold

Claims

1. A vehicle power supply device included in an in-vehicle system comprising a first energy storage unit, a plurality of first loads supplied with power from the first energy storage unit via a power line, and at least one second load supplied with power from the first energy storage unit via the power line, A first conductive path is provided between the power path and the plurality of first loads, A second conductive path is provided between the power path and the at least one second load, A first voltage conversion unit is provided between the power line and the first conductive line, A second voltage conversion unit is provided between the power line and the second conductive line, A switching section provided between the first conductive path and the second conductive path, The system comprises a control unit that controls the first voltage conversion unit, the second voltage conversion unit, and the switching unit, The first voltage conversion unit performs a first conversion operation in which it converts the voltage applied to the power path and applies it to the first conductive path. The second voltage conversion unit performs a second conversion operation in which it converts the voltage applied to the power path and applies it to the second conductive path. The switching unit switches between a first state in which the power supply from the second conductive path to the first conductive path is interrupted, and a second state in which the power supply from the second conductive path to the first conductive path is permitted. All or part of the plurality of first loads and at least one of the second loads, excluding at least one specific first load, have a communication function with the control unit and switch between an activated state and a power-saving state with lower power consumption than the activated state based on a signal output from the control unit. When the control unit detects that the first detection target, which is at least one of the voltage value of the first conductive path and the current value flowing through the first conductive path, falls below the first threshold, it controls the switching unit to the second state and switches all or part of the loads among the plurality of first loads and the at least one second load, excluding the specific first load, to the power-saving state. Vehicle power supply unit.

2. The switching unit switches between a third state in which the power supply from the first conductive path to the second conductive path is interrupted, and a fourth state in which the power supply from the first conductive path to the second conductive path is permitted. All or part of the plurality of first loads and at least one second load, excluding at least one specific second load, have a communication function with the control unit, and switch between the activated state and the power-saving state based on a signal output from the control unit. When the control unit detects that the second detection target, which is at least one of the voltage value of the second conductive path and the current value flowing through the second conductive path, falls below the second threshold, it controls the switching unit to the fourth state and switches all or part of the loads, excluding the specific second load, from the plurality of first loads and at least one of the second loads, to the power-saving state. The vehicle power supply device according to claim 1.

3. The switching unit controls itself to the first state and the third state when the first detection target exceeds an overvoltage threshold greater than the first threshold. The vehicle power supply device according to claim 2.

4. The control unit has a table pre-stored that defines priorities, and determines the load to switch to the power-saving state based on the table. A vehicle power supply device according to any one of claims 1 to 3.

5. The second energy storage unit is electrically connected to the first conductive path. A vehicle power supply device according to any one of claims 1 to 3.

6. The switching unit has a third voltage conversion unit, The third voltage conversion unit performs a third conversion operation that converts the voltage input from the second conductive path and outputs it to the first conductive path. The switching unit causes the third voltage conversion unit to perform the third conversion operation in the second state. A vehicle power supply device according to any one of claims 1 to 3.

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