Vehicle power supply device

Abstract

A vehicle power supply device (20) comprises a control unit (35). When a first detection target, which is at least one of the value of a voltage of a first conductive path (15) and the value of a current flowing through the first conductive path (15), is less than or equal to a first threshold value (V1), the control unit (35): controls a changeover unit (for example, a third voltage conversion unit (23)) to transition to a second state; and changes, to off states, all or a part of switch units (for example, switch units (33, 34)) provided corresponding to, among a plurality of first loads (12, 13) and at least one second load (14), loads (for example, the first load (13) and the second load (14)) excluding a specific first load (for example, the first load (12)).

Description

Vehicle power supply device

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

[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.

[0003] Japanese Unexamined Patent Application Publication No. 2018 - 196234

[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 technique in which insufficient power supply to a specific load is unlikely to occur.

[0006] The vehicle power supply device of the present disclosure is a vehicle power supply device included in an in-vehicle system comprising: a first energy storage unit; a plurality of first loads to which power from the first energy storage unit is supplied via a power line; and at least one second load to which power from the first energy storage unit is supplied via the power line, the vehicle power supply device comprising: a first conductive path provided between the power line and the plurality of first loads; a second conductive path provided between the power line and the at least one second load; a first voltage conversion unit provided between the power line and the first conductive path; a second voltage conversion unit provided between the power line 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 all or part of the loads from the plurality of first loads and the at least one second load, excluding at least one specific first 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 to convert the voltage applied to the power path and apply it to the first conductive path; the second voltage conversion unit performs a second conversion operation to convert the voltage applied to the power path and apply 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 switch unit, when provided in correspondence to the first load, switches between an off state in which the power supply from the first conductive path to the first load corresponding to itself is interrupted and an on state in which it is permitted; when provided in correspondence to the second load, it switches between an off state in which the power supply from the second conductive path to the second load corresponding to itself is interrupted and an on state in which it is permitted. 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 of the at least one second load, excluding the specific first load, to the off state.

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

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

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

[0010] [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, comprising: a first conductive path provided between the power line and the plurality of first loads; a second conductive path provided between the power line and the at least one second load; a first voltage conversion unit provided between the power line and the first conductive path; a second voltage conversion unit provided between the power line 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 all or part of the loads from the plurality of first loads and the at least one second load, excluding at least one specific first load; and a control unit that controls the first voltage conversion unit, the second voltage conversion unit, the switching unit, and the switch unit, wherein the first voltage conversion unit performs a first conversion operation which converts the voltage applied to the power line 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 it cuts off the power supply from the second conductive path to the first conductive path and a second state in which it allows the power supply from the second conductive path to the first conductive path; each switch unit, when provided in correspondence to the first load, switches between an off state in which it cuts off the power supply from the first conductive path to the first load corresponding to it and an on state in which it allows it; when provided in correspondence to the second load, it switches between an off state in which it cuts off the power supply from the second conductive path to the second load corresponding to it and an on state in which it allows it; 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 a first threshold, and switches all or part of the switch units provided in correspondence with the plurality of first loads and the loads of the at least one second load, excluding the specific first load, to the off state.

[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 vehicle power supply device according to [1], wherein the switch unit is provided in correspondence to all or part of 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 side to the second conductive path side is cut off and a fourth state in which the power supply from the first conductive path side to the second conductive path side, the control unit controls the switching unit to the fourth state when a 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 a second threshold, and switches all or part of the switch unit provided in correspondence 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.

[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 vehicle power supply device according to [2], wherein the control 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.

[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 in advance a table that defines the priority, and determines the switch unit to be switched to the OFF state based on the table. The vehicle power supply device according to any one 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 vehicle power supply device according to any one of [1] to [4], wherein the second energy storage unit is electrically connected to the first conductive circuit.

[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, by using the power supplied from the second energy storage unit.

[0020] [6] The vehicle power supply device according to any one of [1] to [5], wherein the switching unit has a third voltage conversion unit, the third voltage conversion unit performs a third conversion operation which converts the voltage input from the second conductive path side and outputs it to the first conductive path side, and the control unit causes the third voltage conversion unit to perform the third conversion operation in the second state.

[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 Embodiments of the Disclosure] 1. First Embodiment 1-1. Configuration of the 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 and 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 comprises 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 in which it stops operating, thereby cutting off the power supply from the first conductive path 15 to the second conductive path 16. The third voltage conversion unit 23 enters a fourth state in which it allows the power supply from the first conductive path 15 to the second conductive path 16 by performing a fourth conversion operation.

[0029] The first detection unit 24 detects the voltage value of the first conductive path 15 as the first detection target. The first detection unit 24 may also detect the current value flowing through the first conductive path 15 as the first detection target. The 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. The second detection unit 25 may also detect the current value flowing through the second conductive path 16 as the second detection target. The 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 configured, for example, to include a microcomputer. The control unit 35 has 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. The operation control unit 35 of the vehicle power supply unit 20 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. The sharing operation is an operation in which, when the output voltage of the first voltage conversion unit 21 is temporarily insufficient, the output voltage of the second voltage conversion unit 22 is shared with the first conductive path 15, and when the output voltage of the second voltage conversion unit 22 is temporarily insufficient, the output voltage of the first voltage conversion unit 21 is shared with the second conductive path 16. 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 becomes equal to or less than the first threshold value V1 in the normal state, 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 switch unit 32 corresponding to a specific first load (in this embodiment, the first load 12) in the on state, the switch units 33 and 34 corresponding to all loads 13 and 14 other than the specific first load 12 among the plurality of first loads 12 and 13 and the second load 14 are switched to the off state. As a result, as shown in FIG. 3, the power supply to the first load 13 and the second load 14 is interrupted, 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] The specific first load may be fixed in advance. The control unit 35 may store in advance a table defining the priorities of the loads 12, 13, and 14, and determine the 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 a plurality of tables. The plurality of tables may be provided corresponding to the state of the vehicle. The state of the vehicle is, for example, whether the vehicle is parked or running, whether it is going straight or turning, whether it is running on a slope or on a flat road, etc. The control unit 35 may select a table corresponding to the state of the vehicle and determine the specific first load based on the selected table.

[0045] Note that the control unit 35 may switch only the switch units corresponding to some of the loads excluding the specific first load 12 among the plurality of first loads 12 and 13 and the second load 14 to the off state. For example, the control unit 35 may switch only the switch units corresponding to the loads with relatively low priorities to the off state based on the above table. How many switch units corresponding to the loads are switched to the off state may be determined based on, for example, the remaining amount of the first power storage unit 10.

[0046] When the second detection target becomes equal to or less than the second threshold value V2 in the normal state, 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 maintaining the switch unit 34 in the on state. As a result, as shown in FIG. 4, the power supply to the first loads 12 and 13 is interrupted, 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] When the first detection target exceeds the overvoltage threshold value V5 in the normal state, the control unit 35 switches the switch units 32, 33, and 34 to the off state, stops the third voltage conversion unit 23, and interrupts the flow of current between the first conductive path 15 and the second conductive path 16. Thereby, it is possible to prevent the overvoltage of the first conductive path 15 from being applied to the first loads 12 and 13 and the second load 14, and it is possible to prevent the overvoltage of the first conductive path 15 from being output to the second conductive path 16.

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

[0049] In this state, when a predetermined supply start condition is satisfied, the control unit 35 causes the first voltage conversion unit 21 to perform a first conversion operation, causes the second voltage conversion unit 22 to perform a second conversion operation, causes the third voltage conversion unit 23 to perform a bridging 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 (48 V), and the voltage of the second conductive path 16 rises to the second target voltage (12 V). The supply start condition may be, for example, that the start switch has been switched to the on state, or may be another condition. The start switch is, 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 when the second failure state occurs. 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 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 bridging 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 its output stops, causing the voltage across the second conductive path 16 to drop. At timing T14, 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 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 across 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 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 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 device 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 device 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 falls 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 switching switch unit 223A and a second switching switch unit 223B. The first switching switch unit 223A and the second switching switch unit 223B are MOSFETs. The first switching switch unit 223A and the second switching switch unit 223B are connected in series between the first conductive path 15 and the second conductive path 16. The first switching switch unit 223A and the second switching 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 switching unit 223 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 the 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 switching 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 plurality of 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 switching 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 the original. 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 a portion of the loads, excluding at least one 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 of the claims are intended to be included.

[0077] 1...In-vehicle system 10...First energy storage unit 11...Power line 12...First load 13...First load 14...Second load 15...First conductive line 16...Second conductive line 17...Second energy storage unit 20...Vehicle power supply unit 21...First voltage conversion unit 22...Second voltage conversion unit 23...Third voltage conversion unit (switching unit) 24...First detection unit 25...Second detection unit 32...Switch unit 33...Switch unit 34...Switch unit 35...Control unit 201...In-vehicle system 220...Vehicle power supply unit 223...Switching unit 223A...First changeover switch unit 223B...Second changeover switch unit 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, comprising: a first conductive path provided between the power line and the plurality of first loads; a second conductive path provided between the power line and the at least one second load; a first voltage conversion unit provided between the power line and the first conductive path; a second voltage conversion unit provided between the power line 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 all or part of the loads from the plurality of first loads and the at least one second load, excluding at least one specific first load; and a control unit that controls the first voltage conversion unit, the second voltage conversion unit, the switching unit, and the switch unit, wherein the first voltage conversion unit performs a first conversion operation which converts the voltage applied to the power line 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 it cuts off the power supply from the second conductive path to the first conductive path and a second state in which it allows the power supply from the second conductive path to the first conductive path; each switch unit, when provided in correspondence to the first load, switches between an off state in which it cuts off the power supply from the first conductive path to the first load corresponding to it and an on state in which it allows it; when provided in correspondence to the second load, it switches between an off state in which it cuts off the power supply from the second conductive path to the second load corresponding to it and an on state in which it allows it; 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 a first threshold, and switches all or part of the switch units provided in correspondence with the plurality of first loads and the loads of the at least one second load, excluding the specific first load, to the off state.

2. The vehicle power supply device according to claim 1, wherein the switch unit is provided in correspondence to all or part of each of the plurality of first loads and the at least one of the second loads, 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 side to the second conductive path side is interrupted and a fourth state in which the power supply from the first conductive path side to the second conductive path side is permitted, and the control unit controls the switching unit to the fourth state when a 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 a second threshold, and switches all or part of the switch unit provided in correspondence to the plurality of first loads and the at least one of the second loads, excluding the specific second load, to the off state.

3. The vehicle power supply device according to claim 2, wherein the control 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.

4. The vehicle power supply device according to any one of claims 1 to 3, wherein the control unit stores a table that defines priorities in advance, and determines the switch unit to be switched to the off state based on the table.

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

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

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