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 switch units (e.g., switch units 33, 34) provided in response to loads (e.g., first load 13, second load 14) among a plurality of first loads 12, 13 and at least one second load 14, excluding a specific first load (e.g., first load 12), to an off state.

Description

Technical Field

[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

[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, embodiments of the present disclosure will be listed and described.

[0010] 〔1〕A vehicle power supply device included in a vehicle-mounted 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 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 switch unit provided corresponding to each of 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, and a control unit that controls the first voltage conversion unit, the second voltage conversion unit, the switching unit, and the switch 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 allowed. When each switch unit is provided corresponding to the first load, it switches between an off state in which power supply from the first conductive path to the first load corresponding to itself is blocked and an on state in which it is allowed. When provided corresponding to the second load, it switches between an off state in which power supply from the second conductive path to the second load corresponding to itself is blocked and an on state in which it is allowed. 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 switch units provided for the loads of the plurality of first loads and the at least one second load, excluding the specific first load, to the off state. Vehicle power supply unit.

[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 and switches all or part of the switch units provided for loads other than the specific first load to the off state. As a result, power can be supplied from the second voltage conversion unit to the specific first load while the power supply to all or part of the loads other than the specific first load is cut off. Therefore, even if the output voltage from the first voltage conversion unit drops 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 switch section is provided in relation to all or part of the loads, including the plurality of first loads and the at least one second load, excluding at least one specific second load. 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. 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 switch units provided for the loads of the plurality of first loads and the at least one second load, excluding the specific second load, to the off state. The vehicle power supply device described in [1].

[0013] The above-described vehicle power supply unit controls the switching unit to a fourth state when the second detection target falls below the second threshold, switching all or part of the switch units provided for loads other than the specific second load to the off state. This allows power to be supplied from the first voltage conversion unit to the specific second load while interrupting the power supply to all or part of the loads other than 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 order in advance, and determines the switch unit to be switched to the OFF 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 switch to the off state based on a predetermined priority.

[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 [4].

[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 [5].

[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, 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] 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, switch units 32, 33, 34, and a control unit 35.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Switch unit 32 is provided corresponding to the first load 12, and switch unit 33 is provided corresponding to the first load 13. Each switch unit 32, 33 is provided between the first conductive path 15 and the first loads 12, 13 corresponding to itself. Each switch unit 32, 33 switches between an off state, which cuts off the power supply from the first conductive path 15 to the first loads 12, 13 corresponding to itself, and an on state, which allows the power supply from the first conductive path 15 to the first loads 12, 13 corresponding to itself.

[0031] The switch unit 34 is provided in accordance with the second load 14. The switch unit 34 switches between an off state, which cuts off the power supply from the second conductive path 16 to the second load 14, and an on state, which allows the power supply from the second conductive path 16 to the second load 14.

[0032] In this embodiment, the switch sections 32, 33, and 34 are composed of MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors), but they may be composed of semiconductor switches other than MOSFETs, or mechanical switches.

[0033] 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.

[0034] 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, the third voltage conversion unit 23, and the switch units 32, 33, and 34.

[0035] In the normal state, the control unit 35 controls the switch units 32, 33, and 34 to the ON state, causing the first voltage conversion unit 21 to perform the first conversion operation and the second voltage conversion unit 22 to perform the 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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. While keeping the switch unit 32 corresponding to a specific first load (first load 12 in this embodiment) in the ON state, the control unit 35 switches the switch units 33 and 34 corresponding to all loads 13 and 14 among the multiple first loads 12 and 13 and second loads 14 except for the specific first load 12 to the OFF state. As a result, as shown in Figure 3, the power supply to the first load 13 and the second load 14 is cut off, 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.

[0044] 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.

[0045] The control unit 35 may also switch off only the switch units corresponding to some of the loads among the multiple first loads 12, 13 and second loads 14, excluding a specific first load 12. For example, the control unit 35 may switch off only the switch units corresponding to loads with relatively lower priority, based on the table described above. The number of loads whose switch units are switched off may be determined, for example, based on the remaining capacity of the first energy storage unit 10.

[0046] 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 switch units 32 and 33 to the off state while keeping the switch unit 34 in the ON 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.

[0047] In the normal state, when the first detection target exceeds the overvoltage threshold V5, the control unit 35 switches the switch units 32, 33, and 34 to the off state and stops the third voltage conversion unit 23, thereby interrupting the current flow between the first conductive path 15 and the second conductive path 16. This prevents the overvoltage of the first conductive path 15 from being applied to the first loads 12, 13 and the second load 14, and prevents the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

[0048] Figure 5 shows a timing chart illustrating an example of operation in the first failure state. At timing T1 in Figure 5, the first voltage conversion unit 21 is stopped, the second voltage conversion unit 22 is stopped, the third voltage conversion unit 23 is stopped, the switch units 32, 33, and 34 are off, the voltage of the first conductive path 15 is 0V, and the voltage of the second conductive path 16 is 0V.

[0049] In this state, when predetermined supply start conditions are met, the control unit 35 causes the first voltage conversion unit 21 to perform a first conversion operation, the second voltage conversion unit 22 to perform a second conversion operation, the third voltage conversion unit 23 to perform a transfer operation, and switches the switch units 32, 33, and 34 to the ON state (timing T2). As a result, the voltage of the first conductive path 15 rises to the first target voltage (48V), and the voltage of the second conductive path 16 rises to the second target voltage (12V). The supply start conditions may be, for example, the start switch being switched to the ON state, or they may be other conditions. The start switch may be, for example, an ignition switch or a power switch.

[0050] Subsequently, at timing T3, the first voltage conversion unit 21 fails and its output stops, causing the voltage across the first conductive path 15 to drop. At timing T4, 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 switch unit 32 in the ON state while switching the switch units 33 and 34 to the OFF state, 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.

[0051] Figure 6 shows a timing chart illustrating an example of operation in the second failure state. At timing T11 in Figure 6, the first voltage conversion unit 21 is stopped, the second voltage conversion unit 22 is stopped, the third voltage conversion unit 23 is stopped, the switch units 32, 33, and 34 are off, the voltage of the first conductive path 15 is 0V, and the voltage of the second conductive path 16 is 0V.

[0052] In this state, when predetermined supply start conditions are met, 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, the third voltage conversion unit 23 to perform the transfer operation, and switches the switch units 32, 33, and 34 to the ON state (timing T12). As a result, the voltage of the first conductive path 15 rises to the first target voltage (48V), and the voltage of the second conductive path 16 rises to the second target voltage (12V).

[0053] Subsequently, at timing T13, the second voltage conversion unit 22 fails, and when the output of the second voltage conversion unit 22 stops, the voltage of the second conductive path 16 decreases. At timing T14, when the control unit 35 determines that the voltage of the second conductive path 16 has fallen below the second threshold V2, it keeps the switch unit 34 in the ON state while switching the switch units 32 and 33 to the OFF state, causing the third voltage conversion unit 23 to perform the fourth conversion operation. As a result, the voltage of the second conductive path 16 returns to the second target voltage.

[0054] Figure 7 shows a timing chart illustrating an example of operation in the third failure state. At timing T21 in Figure 7, the first voltage conversion unit 21 is stopped, the second voltage conversion unit 22 is stopped, the third voltage conversion unit 23 is stopped, the switch units 32, 33, and 34 are off, the voltage of the first conductive path 15 is 0V, and the voltage of the second conductive path 16 is 0V.

[0055] In this state, when predetermined supply start conditions are met, 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, the third voltage conversion unit 23 to perform the transfer operation, and switches the switch units 32, 33, and 34 to the ON state (timing T22). As a result, the voltage of the first conductive path 15 rises to the first target voltage (48V), and the voltage of the second conductive path 16 rises to the second target voltage (12V).

[0056] Subsequently, at timing T23, if the first voltage conversion unit 21 fails and outputs an overvoltage, the voltage of the first conductive path 15 rises. At timing T24, if the control unit 35 determines that the voltage of the first conductive path 15 exceeds the overvoltage threshold V5, it switches the switch units 32, 33, and 34 to the off state and stops the third voltage conversion unit 23. This prevents the overvoltage of the first conductive path 15 from being applied to the first loads 12, 13 and the second load 14, and prevents the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

[0057] 1-4. Effects of the First Embodiment The vehicle power supply unit 20 supplies power to the first load 12 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 switch units 33 and 34 corresponding to all loads 13 and 14 except the specific first load 12 to the off state. As a result, power can be supplied to the specific first load 12 from the second voltage conversion unit 22 while the power supply to all loads 13 and 14 except the specific first load 12 is cut off. 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.

[0058] When the second detection target falls below the second threshold V2, the vehicle power supply unit 20 controls the third voltage conversion unit 23 to the fourth state, switching the switch units 32 and 33 corresponding to all loads 12 and 13 except for the specific second load 14 to the off state. This allows power to be supplied from the first voltage conversion unit 21 to the second load 14 while the power supply to the first loads 12 and 13 is cut off. 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.

[0059] 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.

[0060] The vehicle power supply unit 20 can determine which switch to the off state based on a priority set predetermined by a table.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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, keeping the switch unit 32 corresponding to a specific first load 12 in the ON state, while switching the switch units 33 and 34 corresponding to all loads 13 and 14 among the multiple first loads 12 and 13 and second loads 14 except for the specific first load 12 to the OFF state. As a result, as shown in Figure 10, the power supply to the first load 13 and the second load 14 is cut off, and the output voltage of the second voltage conversion unit 22 is supplied to the first load 12 via the changeover unit 223.

[0070] 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 off only the switch units corresponding to some of the loads, excluding the specific first load 12, from among the multiple first loads 12, 13 and second loads 14. For example, the control unit 35 may switch off only the switch units corresponding to loads with relatively lower priority based on the table. The number of loads whose switch units are switched off may be determined, for example, based on the remaining capacity of the first energy storage unit 10.

[0071] 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, keeping the switch unit 34 corresponding to the second load 14 in the on state, while switching the switch units 32 and 33 corresponding to the multiple first loads 12 and 13 to the off state. As a result, as shown in Figure 11, 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 supplied to the second load 14 via the changeover unit 223.

[0072] In the normal state, when the first detection target exceeds the overvoltage threshold V5, the control unit 35 switches the switch units 32, 33, and 34 to the off 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 prevents the overvoltage of the first conductive path 15 from being applied to the first loads 12, 13 and the second load 14, and prevents the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

[0073] <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.

[0074] The switch section only needs to be provided to correspond to at least some of the loads, excluding a specific first load. In other words, if the specific first load is the first load 12, the switch section corresponding to the first load 12 does not need to be provided, and the switch section corresponding to either the first load 13 or the second load 14 does not need to be provided.

[0075] The second load may be provided in multiple units, similar to the first load. A switch unit may also be provided for each second load. If the second voltage conversion unit fails, the control unit may switch off the switch units corresponding to all or part of the loads, excluding a specific second load.

[0076] 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]

[0077] 1…In-vehicle systems 10…First Energy Storage Unit 11…Power line 12...1st load 13…1st load 14…Second load 15…First conductive path 16…Second conductive circuit 17…Second Energy Storage Unit 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 32…Switch section 33…Switch section 34…Switch section 35…Control Unit 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, A switch unit is provided corresponding to all or part of each of the plurality of first loads and the at least one second load, excluding at least one specific first load. The system comprises a control unit that controls the first voltage conversion unit, the second voltage conversion unit, the switching unit, and the switch 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. Each of the aforementioned switch units, when provided in accordance with the first load, switches between an off state that cuts off the power supply from the first conductive path to the first load corresponding to itself and an on state that allows power supply; when provided in accordance with the second load, it switches between an off state that cuts off the power supply from the second conductive path to the second load corresponding to itself and an on state that allows power supply; 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 switch units provided in response to the plurality of first loads and the loads, excluding the specific first load, among the at least one second load, to the off state. Vehicle power supply unit.

2. The switch section is provided in accordance with each of the plurality of first loads and the loads, excluding at least one specific second load among the plurality of first loads and the at least one second load. 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. 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 switch units provided in response to the plurality of first loads and the loads, excluding the specific second load among the at least one second load, to the off 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 which switch unit to switch to the off 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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