In-vehicle backup control device

Abstract

An on-vehicle backup control device (1) has: a first supply circuit (31) capable of outputting power based on a first power storage unit (71) to a load (93) via a first conduction path (111); a second supply circuit (32) capable of outputting power based on a second power storage unit (72) to a load (92) via a second conduction path (112); and a first control unit (41) and a second control unit (42) which cause, in an external state, the first supply circuit (31) and the second supply circuit (32) to perform a backup operation. The first control unit (41) and the second control unit (42) perform, in the external state, prescribed priority control in which a first backup operation for supplying power based on the second power storage unit (72) to the load (93) is prioritized over a second backup operation for supplying power based on the second power storage unit (72) to the load (93).

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a power storage device that supplies power from a power storage unit to a load when the voltage of the main power supply drops. A control circuit of this power storage device controls a charging circuit when the main power supply is normal, causing the power storage unit to charge. When the voltage of the main power supply drops (for example, when the engine starts after idling stop has ended), this control circuit turns on a switch disposed between the power storage unit and the load to supply power to the load. Patent Document 1 also describes that this power storage device can be applied to a power backup system when the main power supply fails. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-296808 Summary of the Invention [Problem to be solved by the invention]

[0004] The power storage device of Patent Document 1 is configured to supply power from one power storage unit to a load to be backed up. However, with this configuration, there is only one power source for the load during backup, which limits the power supply method.

[0005] The present disclosure provides a method for backing up power to a common load by using both an operation using a first power storage unit and an operation using a second power storage unit, and a method for backing up power to a first load and a second load by using the second power storage unit. 1 To enable priority to be given to backup operation of a load. [Means for solving the problem]

[0006] The in-vehicle backup control device according to the present disclosure includes: An in-vehicle backup control device is used in an in-vehicle power supply system including a power supply unit and a power storage unit, and performs a backup operation of outputting power to a load based on power from the power storage unit when a predetermined external condition occurs in which power supply from the power supply unit to a load is cut off or reduced, a first supply circuit capable of outputting power generated by a first power storage unit, which is one of the power storage units, to a common load via a first conduction path; a second supply circuit capable of outputting power generated by a second power storage unit that is one of the power storage units to the common load via a second conductive path; a control unit that causes the first supply circuit and the second supply circuit to perform the backup operation when the external state is in the abnormal state; and the second supply circuit supplies power based on the second power storage unit to one or more first loads and one or more second loads; The control unit performs a predetermined priority control in the external state to prioritize a first backup operation that supplies power based on the second power storage unit to the first load over a second backup operation that supplies power based on the second power storage unit to the second load. [Effects of the Invention]

[0007] The technology disclosed herein is a method for backing up power to a common load by using both an operation using a first power storage unit and an operation using a second power storage unit, and for backing up power to a first load and a second load by using the second power storage unit. 1 The backup operation of the load can be given priority. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating a schematic example of an in-vehicle power supply system including an in-vehicle backup control device according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing a portion of the block diagram of FIG. 1 in more detail. [Figure 3] FIG. 3 is a flowchart illustrating the flow of control performed by the vehicle-mounted backup control device of the first embodiment. [Figure 4] FIG. 4 shows a subroutine relating to the power supply control to the second load in the flowchart of FIG. [Figure 5] FIG. 5 shows a subroutine relating to the power supply control to the first load in the flowchart of FIG. [Figure 6] FIG. 6 is a diagram illustrating an example in which the actual open-circuit voltage of the second power storage unit falls below the cut-off voltage before a specified time has elapsed in the vehicle-mounted backup control device of FIG. [Figure 7] FIG. 7 is an explanatory diagram illustrating an example in which a specified time period elapses before the actual open-circuit voltage of the second power storage unit falls below the cut-off voltage in the on-board backup control device of FIG. [Figure 8] FIG. 8 is a block diagram that schematically illustrates an example of an in-vehicle power supply system including an in-vehicle backup control device according to the second embodiment. [Figure 9] FIG. 9 is a block diagram illustrating a schematic example of an in-vehicle power supply system including an in-vehicle backup control device according to the third embodiment. [Figure 10] FIG. 10 is a block diagram illustrating a schematic example of an in-vehicle power supply system including an in-vehicle backup control device according to the fifth embodiment. [Figure 11] FIG. 11 is a block diagram illustrating a schematic example of an in-vehicle power supply system including an in-vehicle backup control device according to the sixth embodiment. [Figure 12] FIG. 12 is a block diagram showing a portion of the block diagram of FIG. 11 in more detail. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes exemplary embodiments of the present disclosure. The following exemplary features [1] to [9] may be combined in any manner as long as they are not inconsistent.

[0010] [1] A vehicle-mounted backup control device used in an in-vehicle power supply system having a power supply unit and a power storage unit, which performs a backup operation of outputting power to the load based on power from the power storage unit when a predetermined external condition occurs in which the supply of power from the power supply unit to the load is cut off or reduced, a first supply circuit capable of outputting power generated by a first power storage unit, which is one of the power storage units, to a common load via a first conduction path; a second supply circuit capable of outputting power generated by a second power storage unit that is one of the power storage units to the common load via a second conductive path; a control unit that causes the first supply circuit and the second supply circuit to perform the backup operation when the external state is in the abnormal state; and the second supply circuit supplies power based on the second power storage unit to one or more first loads and one or more second loads; The control unit is an in-vehicle backup control device that performs a predetermined priority control in which, during the external state, a first backup operation that supplies power based on the second power storage unit to the first load takes priority over a second backup operation that supplies power based on the second power storage unit to the second load.

[0011] The on-board backup control device of [1] above can perform backup operation using the power storage unit under a predetermined external condition in which the supply of power from the power supply unit is cut off or reduced. This backup control device can supply power from the first power storage unit and the second power storage unit to a predetermined common load. Therefore, during backup operation, the backup control device can simultaneously use an operation of supplying power from the first power storage unit and an operation of supplying power from the second power storage unit to the common load. In addition, by predetermined priority control by the control unit, the first backup operation (an operation of supplying power based on the second power storage unit to the first load) can be prioritized over the second backup operation (an operation of supplying power based on the second power storage unit to the second load).

[0012] [2] The on-vehicle backup control device according to [1] has the following features. The on-vehicle backup control device includes a third conductive path that is a path for outputting power to the common load and through which power is supplied from the first conductive path and the second conductive path. The first supply circuit includes a first switching element that is provided on the first conductive path and enables current flow from the first power storage unit to the third conductive path when in an ON state and cuts off current flow from the first power storage unit to the third conductive path when in an OFF state. The second supply circuit includes a second switching element that is provided on the second conductive path and enables current flow from the second power storage unit to the third conductive path when in an ON state and cuts off current flow from the second power storage unit to the third conductive path when in an OFF state. The control unit includes a first control unit that controls the first supply circuit and a second control unit that controls the second supply circuit. The first control unit and the second control unit are capable of communicating with each other. During the second backup operation, the first control unit turns the first switching element off, while the second control unit turns the second switching element on, and applies a voltage based on the second storage unit to the third conduction path via the second conduction path, and during the first backup operation, the first control unit turns the first switching element on, while the second control unit turns the second switching element off, and applies a voltage based on the first storage unit to the third conduction path via the first conduction path.

[0013] In the vehicle-mounted backup control device of [2] above, the first and second switching elements can be switched between on and off under the control of the first and second control units that can communicate with each other. Therefore, the first and second switching elements can be selectively turned on. This allows smooth switching between the first backup operation and the second backup operation at a desired timing.

[0014] [3] The on-vehicle backup control device according to [1] has the following features: a third conductive path that is a path for outputting power to the common load and through which power is supplied from the second conductive path; and a diode that is provided between the first conductive path and the third conductive path and has an anode electrically connected to the first conductive path and a cathode electrically connected to the third conductive path. The first supply circuit includes a first conversion unit that increases or decreases an input voltage based on power from the first power storage unit and applies an output voltage to the first conductive path. The second supply circuit includes a second conversion unit that increases or decreases an input voltage based on power from the second power storage unit and applies an output voltage to the second conductive path. During the priority control, the control unit controls the output from the first conversion unit to the first conduction path and the output from the second conversion unit to the second conduction path so that power based on the second storage unit is supplied to the third conduction path via the second conduction path and power based on the first storage unit is cut off by the diode.

[0015] In the vehicle backup control device of [3] above, during priority control by the control unit, power based on the second power storage unit can be supplied to the third conduction path via the second conduction path. When an output voltage is applied to the first conduction path by the first conversion unit, power based on the first power storage unit is cut off by the diode, so that the device can be in a state of preparation for backup to the common load while suppressing power consumption of the first power storage unit. When switching from a state in which power based on the second power storage unit is supplied to the third conduction path to a state in which power based on the first power storage unit is supplied to the third conduction path, the power based on the first power storage unit can be instantly supplied to the third conduction path via the diode. Therefore, interruption of power supply to the common load can be prevented when switching the power source.

[0016] [4] The on-vehicle backup control device according to [3] has the following features: the backup control device includes a first voltage detection unit that detects a voltage of the first conduction path and a second voltage detection unit that detects a voltage of the third conduction path, and the control unit, during the priority control, controls the first conversion unit so that a voltage based on the first power storage unit is applied to the first conduction path, controls the second conversion unit so that a voltage based on the second power storage unit is applied to the third conduction path, and controls the first conversion unit and the second conversion unit based on voltage detection results by the first voltage detection unit and the second voltage detection unit so that the voltage of the third conduction path is maintained at a voltage that blocks current from flowing from the first conduction path to the third conduction path.

[0017] In the vehicle-mounted backup control device of [4] above, during priority control by the control unit, the first conversion unit and the second conversion unit can be controlled based on the voltage detection results by the first voltage detection unit and the second voltage detection unit, so that the voltage applied to the first conduction path based on the power of the first power storage unit and the voltage applied to the second conduction path based on the power of the second power storage unit can be directly controlled.

[0018] [5] The on-vehicle backup control device according to [3] has the following features: a current detection unit that detects a current in the first conduction path; the control unit, during the priority control, controls the first conversion unit so that a voltage based on the first power storage unit is applied to the first conduction path, controls the second conversion unit so that a voltage based on the second power storage unit is applied to the third conduction path, and controls the first conversion unit and the second conversion unit based on a detection result by the current detection unit so that the current flowing from the first conduction path toward the diode approaches zero or less.

[0019] In the above-mentioned [5] vehicle-mounted backup control device, 3It is possible to directly detect whether a current flows through the conductive path. During priority control, the control unit controls the first conversion unit so that a voltage based on the first power storage unit is applied to the first conductive path, and controls the second conversion unit so that a voltage based on the second power storage unit is applied to the third conductive path, thereby controlling the voltage applied to the first conductive path and the voltage applied to the second conductive path to a desired relationship. By controlling the first conversion unit and the second conversion unit so that the current flowing from the first conductive path toward the diode approaches zero or less, even if the current flowing from the first conductive path toward the diode increases, the increase can be suppressed, and a state in which the flow of current from the first conductive path to the third conductive path is blocked can be maintained.

[0020] [6] The on-vehicle backup control device according to [3] has the following features: The control unit includes a first control unit that controls the first supply circuit and a second control unit that controls the second supply circuit. The first control unit and the second control unit are capable of communicating with each other. During the priority control, the first control unit controls the first conversion unit so that a voltage based on the first power storage unit is applied to the first conduction path, the second control unit controls the second conversion unit so that a voltage based on the second power storage unit is applied to the third conduction path, and the first control unit and the second control unit control the first conversion unit and the second conversion unit so that the voltage of the third conduction path is maintained at a voltage that blocks current from flowing from the first conduction path to the third conduction path.

[0021] In the above-mentioned [6] vehicle-mounted backup control device, the first control unit and the second control unit can maintain a state in which current is blocked from flowing from the first conductive path to the third conductive path through mutual communication.

[0022] [7] The on-vehicle backup control device according to any one of [1] to [6] has the following features: the priority control includes limiting control for stopping the supply of power based on the second power storage unit to the second load when the second power storage unit is in a predetermined state, and the control unit performs the limiting control in accordance with the predetermined state until the cumulative operation time of the first load based on the first backup operation reaches a specified time.

[0023] In the vehicle-mounted backup control device of [7] above, when the second power storage unit reaches a predetermined state, the supply of power from the second power storage unit to the second load is stopped (limiting control is performed), so that power consumption by the second load after the predetermined state is reached can be reduced. Therefore, by performing limiting control according to the predetermined state until the cumulative operation time of the first load based on the first backup operation reaches a specified time, it is possible to secure power from the second power storage unit for operating the first load.

[0024] [8] The vehicle backup control device according to [7] has the following feature: the predetermined state is a state in which the open-circuit voltage of the second power storage unit has reached a cut-off voltage set by a predetermined determination method or less.

[0025] In the above-mentioned [8] vehicle-mounted backup control device, it is possible to determine whether the second storage unit is in a predetermined state based on the magnitude of the open-circuit voltage of the second storage unit, thereby making it possible to detect the storage state of the second storage unit more accurately.

[0026] [9] The vehicle backup control device according to any one of [1] to [8] has the following features: The common load is the second load.

[0027] In the vehicle-mounted backup control device of [9] above, the priority of the backup operation to the common load can be lowered in the backup operation using power supplied from the second power storage unit. Furthermore, the common load can perform power backup using the backup operation using power supplied from the first power storage unit. Therefore, the common load can perform backup using power supplied from the first power storage unit while lowering the priority of backup using power supplied from the first power storage unit.

[0028] First Embodiment [Configuration of an automotive power supply system] 1 includes a power supply unit 90, loads 91, 92, 93, 94, and 95, and an in-vehicle backup control device 1. The in-vehicle backup control device 1 is also referred to as a backup control device 1.

[0029] The power supply unit 90 functions as a main power supply that continuously supplies power when the vehicle equipped with the in-vehicle power supply system 100 is started. The power supply unit 90 is a DC power supply that generates DC voltage. The power supply unit 90 is configured by a battery such as a lead battery. The high-potential terminal of the power supply unit 90 is electrically connected to the power path 80, and the low-potential terminal of the power supply unit 90 is electrically connected to ground. The power supply unit 90 applies a predetermined voltage to the power path 80. In this specification, voltage refers to a voltage referenced to ground unless otherwise specified.

[0030] Power supply unit 90 is electrically connected to loads 91, 92, 93, 94, and 95 via power paths 80. Power from power supply unit 90 is supplied to loads 91, 92, 93, 94, and 95 via power paths 80. In the example of FIG. 1 , power paths 80 include power path 81A, which is a conductive path directly connected to power supply unit 90, power path 81B, which is connected to load 91, power path 81C, which is a conductive path connected to load 92, power path 81D, which is a conductive path connected to load 93, power path 81E, which is a conductive path connected to load 94, and power path 81F, which is a conductive path connected to load 95. Power paths 81A, 81B, 81C, 81D, 81E, and 81F are electrically connected to one another. When power is supplied from power supply unit 90 to loads 91, 92, 93, 94, and 95, power paths 81A, 81B, 81C, 81D, 81E, and 81F are at the same potential. Relays, fuses, and the like (not shown) are provided in power path 80, and these elements have the function of interrupting the conduction of power path 80.

[0031] The loads 91, 92, 93, 94, and 95 are in-vehicle electrical devices. The loads 91, 92, 93, 94, and 95 are loads to which a power supply is desired in a predetermined external state (failure state) in which the power supply from the power supply unit 90 is stopped. The loads 91, 92, 93, 94, and 95 may be actuators such as motors. Alternatively, the loads 91, 92, 93, 94, and 95 may be ECUs and actuators in an electric parking brake system, ECUs and actuators in a shift-by-wire control system, or other in-vehicle electrical devices.

[0032] Load 93 corresponds to an example of a "predetermined common load" in the present disclosure. Load 93 can be supplied with power from first power storage unit 71 via first supply circuit 31 (described later), and can be supplied with power from second power storage unit 72 via second supply circuit 32 (described later).

[0033] The backup control device 1 includes a supply circuit 30, a first control unit 41, a second control unit 42, a first detection unit 51, a second detection unit 52, a first power storage unit 71, and a second power storage unit 72. The supply circuit 30 includes a first supply circuit 31 and a second supply circuit 32. The first supply circuit 31 and the second supply circuit 32 may be arranged on the same board or on separate boards. The first control unit 41 and the second control unit 42 correspond to an example of a "control unit" in the present disclosure. The first power storage unit 71 and the second power storage unit 72 correspond to an example of a "power storage unit" in the present disclosure. The backup control device 1 is a device that can perform backup operation to supply power to the loads 91, 92, 93, 94, and 95 based on the power of the first power storage unit 71 and the second power storage unit 72 when a predetermined external condition occurs in which the power supply from the power supply unit 90 to the loads 91, 92, 93, 94, and 95 is cut off or reduced.

[0034] The backup control device 1 has a first power storage unit (base side unit) 101 and a second power storage unit (extension side unit) 102. The first power storage unit 101 has a first power storage section 71, a first control section 41 (described later), a first supply circuit 31, and a first detection section 51. The second power storage unit 102 has a second power storage section 72, a second control section 42 (described later), a second supply circuit 32, and a second detection section 52.

[0035] The first power storage unit 71 and the second power storage unit 72 function as auxiliary power sources. The first power storage unit 71 and the second power storage unit 72 are DC power sources that output DC voltage, and are, for example, electric double layer capacitors. The first power storage unit 71 is electrically connected to a first supply circuit 31 (described later) via a conductive path 15, and is charged and discharged via the first supply circuit 31. The charging voltage (output voltage) of the first power storage unit 71 is the voltage applied to the conductive path 15. The high-potential side terminal of the first power storage unit 71 is electrically connected to the conductive path 15 and has the same potential as the conductive path 15. The low-potential side terminal of the first power storage unit 71 is electrically connected to the ground and has the same potential as the ground.

[0036] The second power storage unit 72 is electrically connected to a second supply circuit 32 (described later) via a conductive path 25, and is charged and discharged via the second supply circuit 32. The charging voltage (output voltage) of the second power storage unit 72 is the voltage applied to the conductive path 25. The high-potential terminal of the second power storage unit 72 is electrically connected to the conductive path 25 and has the same potential as the conductive path 25. The low-potential terminal of the second power storage unit 72 is electrically connected to the ground and has the same potential as the ground.

[0037] In the backup control device 1, when the vehicle in which the in-vehicle power supply system 100 is mounted is in a stopped state with the start switch in an OFF state, the charging voltage (output voltage) of the first power storage unit 71 and the second power storage unit 72 is maintained at or below the standby voltage. When the start switch of the vehicle is switched to an ON state, the backup control device 1 charges the first power storage unit 71 and the second power storage unit 72 so that the charging voltage thereof becomes equal to or above a target voltage that is higher than the standby voltage. When the start switch of the vehicle is in an ON state and no fault condition occurs, the charging voltage of the first power storage unit 71 and the second power storage unit 72 is maintained at the target voltage. When the start switch of the vehicle is switched from an ON state to an OFF state, the backup control device 1 discharges the first power storage unit 71 and the second power storage unit 72 until the charging voltage of the first power storage unit 71 and the second power storage unit 72 becomes equal to or below the standby voltage.

[0038] First supply circuit 31 functions to supply power from first power storage unit 71 to loads 91 and 92 and second supply circuit 32. Second supply circuit 32 functions to supply power to loads 94 and 95.

[0039] The first supply circuit 31 outputs power based on the first power storage unit 71 to the second supply circuit 32. The first supply circuit 31 operates under the control of a first control unit 41, which will be described later. The first supply circuit 31 is disposed between the conductive path 14 and the conductive paths 11, 12, and 13. The first supply circuit 31 has a voltage conversion circuit, such as a DC-DC converter. The voltage conversion circuit performs a charging operation and a discharging operation for the first power storage unit 71. As a charging operation, the voltage conversion circuit performs a voltage conversion operation of increasing or decreasing the voltage applied to the conductive path 14 and applying the voltage to the conductive path 15. As a discharging operation, the voltage conversion circuit performs a voltage conversion operation of increasing or decreasing the voltage applied to the conductive path 15 and applying the voltage to the conductive path 11, etc.

[0040] The second supply circuit 32 switches between a state in which it supplies power based on an input from the first supply circuit 31 to the load 93 and a state in which it supplies power based on the second power storage unit 72 to the load 93. The second supply circuit 32 operates under the control of a second control unit 42, which will be described later. The second supply circuit 32 is disposed between the conductive path 24 and the conductive paths 21, 22, and 23. The second supply circuit 32 has a voltage conversion circuit, such as a DC-DC converter. The voltage conversion circuit performs a charging operation and a discharging operation for the second power storage unit 72. The voltage conversion circuit performs a charging operation, which increases or decreases the voltage applied to the conductive path 24 and applies the resulting voltage to the conductive path 25. When the voltage conversion circuit supplies power based on the second power storage unit 72 to the load 93, the voltage conversion circuit performs a discharging operation, which increases or decreases the voltage applied to the conductive path 25 and applies the resulting voltage to the conductive path 21, etc.

[0041] The first control unit 41 controls the operation of supplying power from the first power storage unit 71 to the load 91, the load 92, and the second supply circuit 32. The first control unit 41 is an information processing device having an information processing function, an arithmetic function, a control function, etc. The first control unit 41 is mainly configured with, for example, a microcomputer, and has an arithmetic unit such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), an A / D converter, etc. The first control unit 41 has a function of controlling the first supply circuit 31.

[0042] The second control unit 42 controls the operation of supplying power from the second power storage unit 72 to the loads 93, 94, and 95. The second control unit 42 is an information processing device having an information processing function, an arithmetic function, a control function, etc. The second control unit 42 is mainly configured with, for example, a microcomputer, and has an arithmetic device such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), an A / D converter, etc. The second control unit 42 has a function of controlling the second supply circuit 32.

[0043] The first detection unit 51 is configured as, for example, a voltage detection circuit. The first detection unit 51 detects the voltage of the conductive path 14. The conductive path 14 is electrically connected to the power path 80 and is at the same potential as the power path 80. Therefore, the first detection unit 51 can detect the voltage of the power path 80.

[0044] The conductive path 11 is a conductive path between the first supply circuit 31 and the load 91. The conductive path 12 is a conductive path between the first supply circuit 31 and the load 92. The conductive path 13 is a conductive path between the first supply circuit 31 and the second supply circuit 32.

[0045] The second detection unit 52 is configured as, for example, a voltage detection circuit. The second detection unit 52 detects the voltage of the conductive path 24. The conductive path 24 is electrically connected to the power path 80 and is at the same potential as the power path 80. Therefore, the second detection unit 52 can detect the voltage of the power path 80.

[0046] The conductive path 21 is a conductive path between the second supply circuit 32 and the load 93. The conductive path 22 is a conductive path between the second supply circuit 32 and the load 94. The conductive path 23 is a conductive path between the second supply circuit 32 and the load 95.

[0047] [Detailed configuration of backup control device] 2 shows an example of a detailed configuration of the backup control device 1. The first supply circuit 31 is capable of outputting power based on the first power storage unit 71 to the load 93 via a first conductive path 111. The first conductive path 111 is a conductive path between a diode 111A and the switching element 33. The anode of the diode 111A is electrically connected to the power path 80. The cathode of the diode 111A is electrically connected to one end of the first conductive path 111. The other end of the first conductive path 111 is electrically connected to the source of the switching element 33.

[0048] The first supply circuit 31 has a first conversion unit 31A, a switching element 31B, and a first drive unit 31C. The first conversion unit 31A is configured as, for example, a DC-DC converter. The first conversion unit 31A is electrically connected to a first conduction path 111. The first conversion unit 31A performs charging and discharging operations on the first power storage unit 71 under the control of the first control unit 41. The first conversion unit 31A performs the following charging operations: Input voltage from the first conductive path 111 By increasing or decreasing the voltage First power storage unit 71 The first conversion unit 31A performs a voltage conversion operation to apply a voltage to the first conduction path 111. As a discharging operation, the first conversion unit 31A boosts or lowers an input voltage based on power from the first power storage unit 71 and applies the output voltage to the first conduction path 111. The switching element 31B is configured as, for example, an N-channel MOSFET. The drain of the switching element 31B is electrically connected to the conductive portion 111C. The conductive portion 111C is a conductive path that constitutes the portion of the first conduction path 111 that is on the power supply unit 90 side. The source of the switching element 31B is electrically connected to the conductive portion 111D. The conductive portion 111D is a conductive path that constitutes the portion of the first conduction path 111 that is on the third conduction path 113 side. The first drive unit 31C is a drive circuit that drives the switching element 31B. The first drive unit 31C outputs a control signal to the gate of the switching element 31B.

[0049] The second supply circuit 32 is capable of outputting power based on the second power storage unit 72 to the load 93 via the second conductive path 112. The second conductive path 112 is a conductive path between the diode 112A and the switching element 33. The anode of the diode 112A is electrically connected to the power path 80. The cathode of the diode 112A is electrically connected to the second conductive path 112.

[0050] The second supply circuit 32 supplies power based on the second power storage unit 72 to one or more loads (e.g., loads 94 and 95) and one or more loads (e.g., load 93). The loads 94 and 95 correspond to the "first load" in the present disclosure. The load 93 corresponds to the "second load" in the present disclosure.

[0051] The second supply circuit 32 has a second conversion unit 32A, a switching element 32B, a switching element 32C, and a second drive unit 32D. The second conversion unit 32A is configured as, for example, a DC-DC converter. The second conversion unit 32A is electrically connected to the second conduction path 112. The second conversion unit 32A performs charging and discharging operations on the second power storage unit 72 under the control of the second control unit 42. The second conversion unit 32A performs the following charging operations: Input voltage from second conductive path 112 By increasing or decreasing the voltage Second power storage unit 72 The second conversion unit 32A performs a voltage conversion operation to apply a voltage to the second conduction path 112. As a discharging operation, the second conversion unit 32A boosts or lowers an input voltage based on power from the second power storage unit 72 and applies the output voltage to the second conduction path 112. The switching element 32B is configured, for example, as an N-channel MOSFET. The drain of the switching element 32B is electrically connected to the conductive portion 112C. The conductive portion 112C is a conductive path that constitutes a portion of the second conduction path 112 on the power supply unit 90 side. The source of the switching element 32B is electrically connected to the conductive portion 112D. The conductive portion 112D is a conductive path that constitutes a portion of the second conduction path 112 on the third conduction path 113 side. The switching element 32C is configured, for example, as an N-channel MOSFET. The source of the switching element 32C is electrically connected to the conductive portion 112D. The drain of the switching element 32C is electrically connected to the third conduction path 113, which will be described later. The second drive unit 32D is a drive circuit that drives the switching element 32B. The second drive unit 32D outputs a control signal to the gate of the switching element 32B.

[0052] The backup control device 1 (more specifically, the second power storage unit 102) further includes a switching element 33, a first voltage detection unit 34, and a second voltage detection unit 35. The switching element 33 is configured as, for example, an N-channel MOSFET. The source of the switching element 33 is electrically connected to the first conduction path 111. The drain of the switching element 33 is electrically connected to the third conduction path 113. The diode 33A is a body diode (parasitic diode) of the switching element 33. The diode 33A is provided between the first conduction path 111 and the third conduction path 113. The anode of the diode 33A is electrically connected to the first conduction path 111 side. The cathode of the diode 33A is electrically connected to the third conduction path 113 side. The diode 33A (more specifically, the switching element 33) may be mounted on the substrate on which the first supply circuit 31 is provided, or may be mounted on the substrate on which the second supply circuit 32 is provided, or may be provided outside the substrate on which the first supply circuit 31 is provided and the substrate on which the second supply circuit 32 is provided.

[0053] The third conductive path 113 is a path that outputs power to the load 93. The third conductive path 113 is a path through which power is supplied from the first conductive path 111 and the second conductive path 112. The third conductive path 113 is electrically connected to the load 93.

[0054] The first voltage detection unit 34 is configured as, for example, a voltage detection circuit. The first voltage detection unit 34 detects the voltage of the first conductive path 111 (more specifically, the conductive portion 111D). The first voltage detection unit 34 can detect a value based on the output voltage from the first conversion unit 31A.

[0055] The second voltage detection unit 35 is configured as, for example, a voltage detection circuit. The second voltage detection unit 35 detects the voltage of the third conductive path 113. The second voltage detection unit 35 can detect a value based on the output voltage from the first conversion unit 31A or a value based on the output voltage from the second conversion unit 32A.

[0056] [Operation of the backup control device] FIG. 3 shows an example of backup control performed by the backup control device 1 (specifically, the first control unit 41 and the second control unit 42). The first control unit 41 and the second control unit 42 start the backup control of FIG. 2 when a predetermined start condition is met. 3 The condition for starting the backup control in FIG. 2 may be, for example, that the start switch of the vehicle equipped with the in-vehicle power supply system 100 has been switched from an off state to an on state, or may be another condition. In a typical example described below, when the start switch of the vehicle has been switched from an off state to an on state, a start signal indicating that the start switch has been switched on is provided from an external device (for example, an external ECU (Electronic Control Unit)) to the first control unit 41 and the second control unit 42. When the first control unit 41 and the second control unit 42 receive such a start signal, they start the backup control in FIG. 2.

[0057] The first control unit 41 and the second control unit 42 are shown in FIG. 3 When the backup control is started, in step S11, charging is performed so that the charging voltages of first power storage unit 71 and second power storage unit 72 become equal to or higher than a target voltage that is higher than the standby voltage. First control unit 41 and second control unit 42 maintain the charging voltages of first power storage unit 71 and second power storage unit 72 at the target voltages.

[0058] The backup standby state continues from the start of backup control until a predetermined drop in the output voltage of the power supply unit 90, which will be described later, is detected (before a Yes determination is made in step S12). In the backup standby state, the first control unit 41 and the second control unit 42 control the output voltage of the second conversion unit 32A to be higher than the output voltage of the first conversion unit 31A. In the backup standby state, the first control unit 41 controls the switching element 31B to be turned on. The second control unit 42 controls the switching element 32B to be turned on, the switching element 32C to be turned off, and the switching element 33 to be turned off.

[0059] In step S12, the first control unit 41 and the second control unit 42 determine whether the output voltage of the power supply unit 90 (main power supply) is low (in a predetermined low state). The first control unit 41 determines whether the voltage of the conductive path 14 is below a threshold (in a predetermined low state) based on, for example, the voltage detected by the first detection unit 51. This threshold is a value significantly smaller than the output voltage that the power supply unit 90 applies to the power path 80 under normal conditions and is a value greater than zero. Alternatively, the second control unit 42 may determine whether the voltage of the conductive path 24 is below a threshold (in a predetermined low state) based on the voltage detected by the second detection unit 52. If the first control unit 41 determines in step S12 that the voltage of the conductive path 14 is below the threshold (Yes in step S12), the process proceeds to step S13. In this representative example, the case where the voltage of the conductive path 14 is below the threshold, i.e., the case where the voltage of the power path 80 is below the threshold, corresponds to an example of a "predetermined external state." If the first control unit 41 determines in step S12 that the voltage of the conductive path 14 is equal to or higher than the threshold value (No in step S12), it performs the process of step S11 again.

[0060] For example, in an abnormal state in which a ground fault or disconnection occurs in power path 80 and power supply from power supply unit 90 to conductive paths 14 and 24 and power supply to power paths 81B, 81C, 81D, 81E, and 81F is interrupted, the voltage of conductive paths 14 and 24 becomes approximately 0 V. In such a case, in backup control device 1, first control unit 41 and second control unit 42 perform backup operation to supply power to multiple loads 91, 92, 93, 94, and 95 based on the power from first power storage unit 71 and second power storage unit 72. Second control unit 42 performs processing from step S13 onward for loads 93, 94, and 95. Note that, hereinafter, a description of the backup operation performed by first control unit 41 for loads 91 and 92 will be omitted, and an example in which power is supplied to loads 93, 94, and 95 by second control unit 42 will be described.

[0061] If the second control unit 42 determines in step S12 that the voltage of the conductive path 14 is less than the threshold value (Yes in step S12), it starts supplying power to the loads 93, 94, and 95 in step S13. The second control unit 42 causes the second supply circuit 32 to supply power to the conductive paths 21, 22, and 23. When the backup operation (step S13) is started, the switching element 31B is maintained in the on state. This causes the first conversion unit 31A to turn off the diode 33. A The switching element 32B is maintained in the ON state. This allows current to flow from the second conversion unit 32A to the third conduction path 113. Furthermore, the switching element 32C is maintained in the OFF state, and the switching element 33 is maintained in the OFF state.

[0062] In the subsequent step S14, second control unit 42 controls the power supply to load 93. In the power supply control to load 93, as shown in Fig. 4, second control unit 42 first determines whether the open circuit voltage (OCV) of second power storage unit 72 is equal to or lower than the cut-off voltage (step S21). The open circuit voltage Vocv of second power storage unit 72 can be calculated using, for example, the following relational expression (1). Vocv=Vccv-I×R (1) Vccv is a closed circuit voltage, which is an output voltage from second power storage unit 72. I is a current flowing through second power storage unit 72. R is an internal resistance.

[0063] The cut-off voltage is a voltage threshold set by a predetermined determination method. For example, the cut-off voltage may be determined by an arithmetic expression in which the cumulative operating time t is a variable and the cut-off voltage is set to be lower as t increases. The cut-off voltage may also be determined by an arithmetic expression that sets the cut-off voltage based on the amount of power consumed by the loads 94, 95 since the start of backup operation. As shown in FIG. 6, the cut-off voltage (load 93 cut-off voltage) may be determined as a voltage equivalent to the operating energy of the loads 94, 95 (the energy that allows the loads 94, 95 to operate for the remaining time). Alternatively, the cut-off voltage may be determined as a fixed value.

[0064] When second control unit 42 determines in step S21 that the open-circuit voltage of second power storage unit 72 is not equal to or less than the cut-off voltage (is greater than the cut-off voltage) (No in step S21), second control unit 42 performs supply control by second supply circuit 32. (Step S22) The second control unit 42 controls the second supply circuit 32 to output power based on the second power storage unit 72 to the load 93 via the second conduction path 112. Here, the first control unit 41 and the second control unit 42 control the first conversion unit 31A and the second conversion unit 32A based on the voltage detection results by the first voltage detection unit 34 and the second voltage detection unit 35 so as to maintain the voltage of the third conduction path 113 at a voltage that blocks current from flowing from the first conduction path 111 to the third conduction path 113. For example, the first control unit 41 controls the cathode voltage of the diode 33A (the voltage of the third conduction path 113) to a value greater than the anode voltage of the diode 33A (the voltage of the first conduction path 111). Then, the switching element 31B maintains an ON state. The switching element 32B maintains an ON operation. Furthermore, the switching element 32C is turned ON by the control of the second control unit 42. The switching element 33 maintains an OFF operation.

[0065] On the other hand, when the first control unit 41 and the second control unit 42 determine in step S21 that the open circuit voltage of the second power storage unit 72 is equal to or lower than the cut-off voltage (Yes in step S21), they stop the supply control by the second supply circuit 32 and perform the supply control by the first supply circuit 31. (Step S23) . 2 Control unit 4 2 The supply of power from second power storage unit 72 to load 93 is stopped. 1 Control unit 4 1 is the 1 Supply circuit 3 1 Controlling the 1 Power storage unit 7 1 The power based on the first conductive path 11 1 Specifically, the switching element 31B is maintained in an ON state. Under the control of the second control unit 42, the switching element 32B is turned off, the switching element 32C is turned off, and the switching element 33 is turned on. The first control unit 41 and the second control unit 42 perform step S2 2 ,S23 After the above process, step S15 in FIG. 3 is performed.

[0066] In the subsequent step S15, the first control unit 41 and the second control unit 42 perform power supply control for the loads 94, 95. In the power supply control for the loads 94, 95, as shown in FIG. 5, the second control unit 42 first determines whether a predetermined time for the loads 94, 95 has elapsed (step S31). The predetermined time is, for example, a time set in advance for continuously operating the loads 94, 95. The predetermined time is set, for example, based on the power consumption of each operation of the loads 94, 95 or the number of planned operations. Note that continuously operating the loads 94, 95 within the predetermined time includes both continuous operation of the loads 94, 95 and intermittent operation of the loads 94, 95. For example, as shown in FIG. 7, the predetermined time is the time from the start of backup operation until the operating energy of the loads 94, 95 (energy sufficient for the remaining operation of the loads 94, 95) falls below a predetermined lower limit voltage.

[0067] If the first control unit 41 and the second control unit 42 determine in step S31 that the specified time for the loads 94, 95 has elapsed, then in the following step S32, they stop the power supply to the loads 94, 95. Thereafter, the first control unit 41 and the second control unit 42 perform step S16 shown in Fig. 3. On the other hand, if the first control unit 41 and the second control unit 42 determine in step S31 that the specified time for the loads 94, 95 has not elapsed, they perform step S16 shown in Fig. 3.

[0068] Through the processing of steps S14 and S15, the first control unit 41 and the second control unit 42 perform predetermined priority control that prioritizes the first backup operation over the second backup operation during an external state. The first backup operation is an operation of supplying power based on the second power storage unit 72 to the loads 94 and 95. The second backup operation is an operation of supplying power based on the second power storage unit 72 to the load 93. The priority control includes limit control (step S23) that stops the supply of power based on the second power storage unit 72 to the load 93 when the second power storage unit 72 is in a predetermined state. The first control unit 41 and the second control unit 42 perform the limit control (step S23) according to the predetermined state until the cumulative operation time of the loads 94 and 95 based on the first backup operation reaches a specified time (until step S31 returns Yes).

[0069] During priority control, the first control unit 41 and the second control unit 42 control the output by the first conversion unit 31A to the first conduction path 111 and the output by the second conversion unit 32A to the second conduction path 112 so that power based on the second power storage unit 72 is supplied to the third conduction path 113 via the second conduction path 112 and power based on the first power storage unit 71 is cut off by the diode 33A. Specifically, during priority control, the first control unit 41 and the second control unit 42 control the first conversion unit 31A so that the voltage based on the first power storage unit 71 is applied to the first conduction path 111, and control the second conversion unit 32A so that the voltage based on the second power storage unit 72 is applied to the third conduction path 113. Furthermore, based on the voltage detection results by the first voltage detection unit 34 and the second voltage detection unit 35, the first control unit 41 and the second control unit 42 control the first conversion unit 31A and the second conversion unit 32A to maintain the voltage of the third conduction path 113 at a voltage that blocks current from flowing from the first conduction path 111 to the third conduction path 113. For example, the first control unit 41 and the second control unit 42 control the cathode voltage of the diode 33A (the voltage of the third conduction path 113) to a value greater than the anode voltage of the diode 33A (the voltage of the first conduction path 111). This allows power to be selectively supplied to the load 93 only from the second power storage unit 72. When switching from a state in which power based on the second power storage unit 72 is supplied to the third conduction path 113 to a state in which power based on the first power storage unit 71 is supplied to the third conduction path 113, the power based on the first power storage unit 71 can be instantly supplied to the third conduction path 113 via the diode 33A. Therefore, when switching the power source, it is possible to prevent the power supply to the load 93 from being interrupted.

[0070] After performing power supply control to the loads 94, 95 (step S15), the first control unit 41 and the second control unit 42 determine in the subsequent step S16 whether the vehicle in which the in-vehicle power supply system 100 is installed is in a stopped state. The first control unit 41 and the second control unit 42 determine whether the start switch of the vehicle in which the in-vehicle power supply system 100 is installed has been switched from an on state to an off state. For example, when the start switch of the vehicle is switched from an on state to an off state, a start signal indicating that the start switch has been switched to an off state is provided to the first control unit 41 and the second control unit 42 from an external device (e.g., an external ECU (Electronic Control Unit)). When the first control unit 41 and the second control unit 42 receive such a start signal, they determine that the vehicle is in a stopped state. When the first control unit 41 and the second control unit 42 determine in step S16 that the vehicle is not in a stopped state (is in a running state) (No in step S16), they perform the process of step S14 again. If it is determined in step S16 that the vehicle is in a stopped state (Yes in step S16), the first control unit 41 and the second control unit 42 end the backup control in FIG.

[0071] The following description relates to an example of the effect of this configuration. The backup control device 1 can perform a backup operation using the first power storage unit 71 and the second power storage unit 72 in an external state in which the supply of power from the power supply unit 90 is cut off or reduced. The backup control device 1 can supply power from the first power storage unit 71 and the second power storage unit 72 to a predetermined common load (load 93). Therefore, during backup operation, the backup control device 1 can simultaneously use an operation of supplying power from the first power storage unit 71 and an operation of supplying power from the second power storage unit 72 to the common load. In addition, by predetermined priority control by the first control unit 41 and the second control unit 42, the first backup operation (an operation of supplying power based on the second power storage unit 72 to the loads 94, 95) can be prioritized over the second backup operation (an operation of supplying power based on the second power storage unit 72 to the load 93).

[0072] Furthermore, in the backup control device 1, when the second power storage unit 72 is in a predetermined state, the load of the power based on the second power storage unit 72 is 93 Since the supply to the load is stopped (limiting control is performed), the load after the specified state is reached 93 Therefore, by performing limit control in accordance with a predetermined state until the cumulative operation time of loads 94, 95 based on the first backup operation reaches a specified time, it is possible to ensure the power of second power storage unit 72 for operating loads 94, 95.

[0073] Furthermore, the backup control device 1 can determine whether the second storage unit 72 is in a predetermined state based on the magnitude of the open-circuit voltage of the second storage unit 72, thereby making it possible to detect the storage state of the second storage unit 72 with greater accuracy.

[0074] In the backup control device 1, during priority control by the first control unit 41 and the second control unit 42, power based on the second power storage unit 72 can be supplied to the third power conduction path 113 via the second power conduction path 112. When the first conversion unit 31A applies an output voltage to the first power conduction path 111, the power based on the first power storage unit 71 is cut off by the diode 33A, so that the backup control device 1 can be prepared for backup to the common load (load 93) while suppressing power consumption of the first power storage unit 71. When switching from a state in which power based on the second power storage unit 72 is supplied to the third power conduction path 113 to a state in which power based on the first power storage unit 71 is supplied to the third power conduction path 113, the power based on the first power storage unit 71 can be immediately supplied to the third power conduction path 113 via the diode 33A. Therefore, when switching the power source, interruption of the power supply to the common load (load 93) can be prevented.

[0075] In the backup control device 1, during priority control by the first control unit 41 and the second control unit 42, the first conversion unit 31A and the second conversion unit 32A can be controlled based on the voltage detection results by the first voltage detection unit 34 and the second voltage detection unit 35. Therefore, the voltage applied to the first conduction path 111 based on the power of the first power storage unit 71 and the voltage applied to the second conduction path 112 based on the power of the second power storage unit 72 can be directly controlled.

[0076] In the backup control device 1, the priority of the backup operation to the common load (load 93) can be lowered in the backup operation using power supplied from the second power storage unit 72. In addition, the common load (load 93) can perform power backup through the backup operation using power supplied from the first power storage unit 71. Therefore, the common load (load 93) can perform backup using power supplied from the first power storage unit 71, while the priority of backup using power supplied from the first power storage unit 71 can be lowered.

[0077] Second Embodiment The in-vehicle power supply system 200 of the second embodiment is different from the first embodiment in that a current detection unit 234 is provided instead of the first voltage detection unit 34 and the second voltage detection unit 35, but is otherwise the same as the first embodiment. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and detailed explanations will be omitted.

[0078] 8, in the in-vehicle power supply system 200, the second power storage unit 102 has a current detection unit 234. The current detection unit 234 is configured as a current detection circuit. The current detection unit 234 detects the current in the first conductive path 111 (more specifically, the conductive portion 111D).

[0079] The backup control of the backup control device 1 is similar to that of the first embodiment, but differs from that of the first embodiment in the following specific control content. During priority control, the first control unit 41 and the second control unit 42 control the first conversion unit 31A so that a voltage based on the first power storage unit 71 is applied to the first conduction path 111, and control the second conversion unit 32A so that a voltage based on the second power storage unit 72 is applied to the third conduction path 113. During priority control, the control unit further controls the first conversion unit 31A and the second conversion unit 32A based on the detection result of the current detection unit 234 so that the current flowing from the first conduction path 111 toward the diode 33A approaches zero or less. For example, the control unit controls the voltage of the cathode of the diode 33A (the voltage of the third conduction path 113) to a value greater than the voltage of the anode of the diode 33A (the voltage of the first conduction path 111). This allows power to be selectively supplied to the load 93 only from the second power storage unit 72.

[0080] In the backup control device 1, the first conductive path 111 is connected to the 3 Conductive path 11 3 Whether a current flows through the first and second conduction paths 111 and 112 can be directly detected. During priority control, the first control unit 41 and the second control unit 42 control the first conversion unit 31A so that a voltage based on the first power storage unit 71 is applied to the first conduction path 111, and control the second conversion unit 32A so that a voltage based on the second power storage unit 72 is applied to the third conduction path 113. This allows the voltage applied to the first conduction path 111 and the voltage applied to the second conduction path 112 to be controlled to a desired relationship. By controlling the first conversion unit 31A and the second conversion unit 32A so that the current flowing from the first conduction path 111 toward the diode 33A approaches zero or less, even if the current flowing from the first conduction path 111 toward the diode 33A increases, the increase can be suppressed, and a state in which the current flowing from the first conduction path 111 to the third conduction path 113 is blocked can be maintained. When switching the power source, an interruption in the power supply to the common load (load 93) can be prevented.

[0081] Third Embodiment The in-vehicle power supply system 300 of the third embodiment differs from the first embodiment in that the first control unit 41 and the second control unit 42 are capable of communicating with each other, but is otherwise the same as the first embodiment. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0082] Automotive Power Supply Systems 300 9, the backup control device 1 has a first control unit 41 and a second control unit 42. The first control unit 41 and the second control unit 42 can communicate with each other. For example, the communication between the first control unit 41 and the second control unit 42 may be CAN (Control Area Network) communication, LIN (Local Interconnect Network) communication, or the like, but the communication method is not limited thereto.

[0083] The backup control of the backup control device 1 is the same as in the first embodiment (FIGS. 3 to 5), and the following mainly describes the control content (priority control) that differs from the first embodiment. First, as in the first embodiment, in the backup standby state, the first control unit 41 and the second control unit 42 control the output voltage of the second conversion unit 32A to be higher than the output voltage of the first conversion unit 31A. In the backup standby state, the first control unit 41 controls the switching element 31B to be turned on. The second control unit 42 controls the switching element 32B to be turned on, the switching element 32C to be turned off, and the switching element 33 to be turned off.

[0084] In the backup control of the backup control device 1 (FIGS. 3 to 5), when the backup operation (step S13) is started, switching element 31B is maintained in the ON state. Switching element 32B is maintained in the ON state. Furthermore, switching element 32C is maintained in the OFF state, and switching element 33 is maintained in the OFF state.

[0085] During priority control, the first control unit 41 controls the first conversion unit 31A so that the voltage based on the first power storage unit 71 is applied to the first conduction path 111, and the second control unit 42 controls the second conversion unit 32A so that the voltage based on the second power storage unit 72 is applied to the third conduction path 113. Furthermore, the first control unit 41 and the second control unit 42 control the first conversion unit 31A and the second conversion unit 32A so that the voltage of the third conduction path 113 is maintained at a voltage that blocks current from flowing from the first conduction path 111 to the third conduction path 113. For example, the voltage of the cathode of the diode 33A (the voltage of the third conduction path 113) is controlled to a value greater than the voltage of the anode of the diode 33A (the voltage of the first conduction path 111). The switching elements 31B and 32B are maintained in an ON state. Furthermore, the switching element 32C is turned on by control of the second control unit 42. The switching element 33 is maintained in an OFF state. As a result, power is selectively supplied to the load 93 only from the second power storage unit 72. In this manner, by mutual communication between the first control unit 41 and the second control unit 42, it is possible to maintain a state in which current is blocked from flowing from the first conductive path 111 to the third conductive path 113.

[0086] When it is determined that the open circuit voltage of second power storage unit 72 is equal to or lower than the cut-off voltage (Yes in step S21), supply control by second supply circuit 32 is stopped, and supply control by first supply circuit 31 is performed. Specifically, switching element 31B remains in an ON state. Under the control of second control unit 42, switching element 32B is turned off, switching element 32C is turned off, and switching element 33 is turned on. When switching the power source, it is possible to prevent interruption of power supply to the common load (load 93).

[0087] <Fourth embodiment> The in-vehicle power supply system of the fourth embodiment has the same configuration as the in-vehicle power supply system of the third embodiment, and is different from the third embodiment in some respects regarding the backup control of the backup control device 1, but is otherwise the same. Note that the same components as those of the third embodiment are given the same reference numerals, and detailed explanations will be omitted.

[0088] In the backup control device 1, the first control unit 41 and the second control unit 42 can communicate with each other, similarly to the third embodiment.

[0089] In the backup control of the backup control device 1 (FIGS. 3 to 5), mainly the control (priority control) that differs from the third embodiment will be described below. First, as in the third embodiment, in the backup standby state, the first control unit 41 and the second control unit 42 control the output voltage of the second conversion unit 32A to be higher than the output voltage of the first conversion unit 31A. In the backup standby state, the first control unit 41 controls the switching element 31B to be turned on. The second control unit 42 controls the switching element 32B to be turned on, the switching element 32C to be turned off, and the switching element 33 to be turned off.

[0090] The backup operation (step S13) is started, and the switching element 31B is turned off under the control of the first control unit 41. As a result, the first conversion unit 31A is switched off and the diode 33 A The power supply to the anode of the second conversion unit 32A is cut off. The switching element 32B is maintained in the ON state. This allows power to be supplied from the second conversion unit 32A to the third conduction path 113. Furthermore, the switching element 32C is maintained in the ON state, and the switching element 33 is maintained in the OFF state. By selectively turning on the switching element 32B in this manner, the backup control device 1 applies a voltage based on the second power storage unit 72 to the third conduction path 113 via the second conduction path 112 (step S22).

[0091] When the open-circuit voltage of second power storage unit 72 becomes equal to or lower than the cut-off voltage (Yes in step S21), first control unit 41 and second control unit 42 communicate with each other to cause first control unit 41 to turn on switching element 31B. AThe switching element 32B is maintained in an ON state. Furthermore, the switching element 32C is turned off under the control of the second control unit 42. The switching element 33 is maintained in an OFF state. 3 or switching element 31B The larger of the voltage applied to the second power storage unit 72 and the voltage applied to the switching element 32C is applied to the third conductive path 113. A Alternatively, a current flows to the third conductive path 113 via the body diode of the switching element 32C.

[0092] When the power source is completely switched from second power storage unit 72 to first power storage unit 71 (step S23), switching element 31B is turned on under the control of first control unit 41. As a result, power is transferred from first conversion unit 31A to diode 33. A The second control unit 42 controls the switching element 32B to be turned off, thereby cutting off current from the second conversion unit 32A to the third conduction path 113. The second control unit 42 controls the switching element 33 to be turned on, thereby enabling current to flow from the first conversion unit 31A to the third conduction path 113. By selectively turning on the switching element 31B in this way, the backup control device 1 applies a voltage based on the first power storage unit 71 to the third conduction path 113 via the first conduction path 111. When switching the power source, it is possible to prevent interruption of the power supply to the common load (load 93).

[0093] Fifth Embodiment The in-vehicle power supply system 400 of the fifth embodiment is different from the fourth embodiment in that a switching element 433 is provided instead of the switching element 33, but is otherwise the same as the fourth embodiment. Note that the same components as those of the fourth embodiment are denoted by the same reference numerals, and detailed explanations thereof will be omitted.

[0094] 10 , in the in-vehicle power supply system 400, the backup control device 1 (more specifically, the first power storage unit 101) has a switching element 433. The switching element 433 is provided between the first conductive path 111 and the third conductive path 113. The first conductive path 111 is provided between the diode 111A and the switching element 433. The third conductive path 113 is provided between the switching element 433, the switching element 32C, and the load 93.

[0095] The switching element 433 is configured as, for example, an N-channel MOSFET. The source of the switching element 433 is electrically connected to one end (the end on the load 93 side) of the first conduction path 111. The drain of the switching element 433 is electrically connected to the third conduction path 113. The diode 433A is a body diode (parasitic diode) of the switching element 433. The diode 433A is provided between the first conduction path 111 and the third conduction path 113. The anode of the diode 433A is electrically connected to the first conduction path 111 side. The cathode of the diode 433A is electrically connected to the third conduction path 113 side. The diode 433A (more specifically, the switching element 433) may be mounted on the substrate on which the first supply circuit 31 is provided, or may be mounted on the substrate on which the second supply circuit 32 is provided, or may be provided outside the substrate on which the first supply circuit 31 is provided and the substrate on which the second supply circuit 32 is provided.

[0096] The backup control of the backup control device 1 (FIGS. 3 to 5) is the same as that in the third embodiment. Specifically, the switching element 433 performs on / off operation at the same timing as the switching element 33 in the third embodiment. That is, the switching element 433 performs on operation at the same timing as the switching element 33 in the third embodiment performs on operation, and performs off operation at the same timing as the switching element 33 in the third embodiment performs off operation.

[0097] The in-vehicle power supply system 400 of the fifth embodiment can achieve the same effects as the in-vehicle power supply system of the fourth embodiment. In particular, when the backup operation of the backup control device 1 (step S13) is started, the diode 4 The cathode voltage of 33A (the voltage of the third conductive path 113) is applied to the diode 4 The voltage is controlled to a value greater than the anode voltage (voltage of first conductive path 111) of 33 A. This allows power to be selectively supplied to load 93 from second power storage unit 72 alone.

[0098] Sixth Embodiment The in-vehicle power supply system 500 of the sixth embodiment has a switching unit 533, and differs from the first embodiment mainly in that the power supplied to the load 93 is switched by the switching unit 533, but is otherwise the same as the first embodiment. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0099] 11 , in the in-vehicle power supply system 500, the supply circuit 530 of the backup control device 1 has a first supply circuit 31, a second supply circuit 32, and a switching unit 533. The first supply circuit 31 functions to supply power to the switching unit 533. The first supply circuit 31 outputs power based on the first power storage unit 71 to the switching unit 533 via a first conductive path 511. The first conductive path 511 is a conductive path between the first supply circuit 31 and the switching unit 533.

[0100] The second supply circuit 32 functions to supply power to the switching unit 533. The second supply circuit 32 outputs power based on the second power storage unit 72 to the switching unit 533 via the second conductive path 512. The second conductive path 512 is a conductive path between the second supply circuit 32 and the switching unit 533. The conductive path 534 is a conductive path between the switching unit 533 and the load 93.

[0101] The switching unit 533 switches between a state in which power based on the output from the first supply circuit 31 is supplied to the load 93 and a state in which power based on the output from the second supply circuit 32 is supplied to the load 93. The switching unit 533 has, for example, a switch. The switching unit 533 operates under the control of, for example, the first control unit 41 and the second control unit 42.

[0102] FIG. 12 shows an example of a detailed configuration of the backup control device 1. This embodiment differs from the first embodiment in that the first control unit 41 and the second control unit 42 are capable of communicating with each other. For example, the communication between the first control unit 41 and the second control unit 42 may be performed using a control area network (CAN) communication, a local interconnect network (LIN) communication, or any other communication method. The switching unit 533 has a diode 535 and a diode 536. The first conductive path 511 is provided between the diode 111A and the diode 535. The second conductive path 512 is provided between the diode 112A and the diode 536. The third conductive path 513 is provided between the diode 535, the diode 536, and the load 93.

[0103] The anode of the diode 535 is electrically connected to the other end (the end on the load 93 side) of the first conductive path 511. The cathode of the diode 535 is electrically connected to the cathode of the diode 536 and one end (the end on the power supply unit 90 side) of the third conductive path 513. The anode of the diode 536 is electrically connected to the other end (the end on the load 93 side) of the second conductive path 512. The load 93 is electrically connected to the other end of the third conductive path 513.

[0104] The backup control of the backup control device 1 is the same as in the first embodiment (FIGS. 3 to 5), and the control content (priority control) that differs from the first embodiment will be mainly described below. First, as in the first embodiment, in the backup standby state, the first control unit 41 and the second control unit 42 control the output voltage of the second conversion unit 32A to be higher than the output voltage of the first conversion unit 31A. In the backup standby state, the first control unit 41 controls the switching element 31B to be turned off. The second control unit 42 controls the switching element 32B to be turned off.

[0105] In the backup control of the backup control device 1 (FIGS. 3 to 5), when the backup operation (step S13) is started, the switching element 31B is turned on under the control of the first control unit 41. The switching element 32B is turned on under the control of the second control unit .

[0106] During priority control, the first control unit 41 and the second control unit 42 perform control so that the output voltage of the second conversion unit 32A is greater than the output voltage of the first conversion unit 31A. More specifically, the first conversion unit 31A and the second conversion unit 32A are connected to the diode 53 6 The voltage applied to 2 Conductive path 51 2 voltage) to diode 53 5 The voltage applied to 1 Conductive path 51 1 The on state of switching element 31B and switching element 32B is maintained. This allows power to be selectively supplied to load 93 only from second power storage unit 72. In this way, the mutual communication between first control unit 41 and second control unit 42 can maintain a state in which current is blocked from flowing from first conductive path 511 to third conductive path 513.

[0107] When it is determined that the open circuit voltage of second power storage unit 72 is equal to or lower than the cut-off voltage (Yes in step S21), the supply control by second supply circuit 32 is stopped, and supply control by first supply circuit 31 is performed. Specifically, switching element 31B remains in an on state. Switching element 32B is turned off under the control of second control unit 42. When switching the power source, it is possible to prevent interruption of the power supply to the common load (load 93).

[0108] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiment may be modified as follows.

[0109] In the first to third embodiments, the diode 33A is configured as a body diode (parasitic diode) of the switching element 33, but it may be configured as a general forward diode. 5 The same applies to the diode 433A of the embodiment.

[0110] In the above embodiment, in the backup control of the backup control device 1, a state in which the voltage of the conductive path 14 is less than the threshold value is exemplified as the predetermined external state in step S12, but other states may also be used. For example, the predetermined external state may be a state in which a backup operation is requested from the load (specifically, a state in which at least one of the first control unit 41 and the second control unit 42 receives a signal requesting a backup operation from the load).

[0111] In the above embodiment, during backup control (priority control) of the backup control device 1, the output voltage of the second conversion unit 32A is set to be higher than the output voltage of the first conversion unit 31A, but control of either the first conversion unit 31A or the second conversion unit 32A may be stopped. In the present disclosure, "controlling the first conversion unit and the second conversion unit" also includes stopping the operation of either the first conversion unit 31A or the second conversion unit 32A by stopping control by either the first control unit 41 or the second control unit 42.

[0112] Above No. 1 to No. 5 In the embodiment, the load 93 is electrically connected to the second power storage unit 102, but may be electrically connected to the first power storage unit 101. In this case, the first power storage unit 101 is supplied with power from the second power storage unit 102 and switches the power source for the load 93 (the first to second power storage units 102 and 101 are the same as those described above). 5 The second power storage unit 102 has the same configuration as the second power storage unit 102 in the embodiment.

[0113] In the above embodiment, limiting control (step S23) was performed according to a predetermined state until the cumulative operation time reached the specified time (until step S31 turned out to be Yes), but control may also be performed so that power is not supplied to the load 93 until the cumulative operation time reaches the specified time.

[0114] In the above embodiment, the limiting control (step S23) was performed depending on the predetermined state until the cumulative operation time reached the specified time (until the answer in step S31 was Yes), but priority control may be performed such that the limiting control is performed until a certain time has elapsed since the occurrence of the external state (or the start of the backup operation), or control may be performed such that power is not supplied to the load 93 until a certain time has elapsed since the occurrence of the external state (or the start of the backup operation).

[0115] In the above embodiment, the operations of the loads 94 and 95 may not be restricted, and priority control may be performed on the load 93 so as to keep the total power consumption within a predetermined range.

[0116] In the above embodiment, a start switch for a vehicle is described, but the start switch may be an ignition switch, or in the case of an electric vehicle, it may be a power switch for controlling an EV system.

[0117] In the above embodiment, the power supply unit is a lead battery, but is not limited to a lead battery. The power supply unit may be, for example, another type of battery such as a lithium ion battery, or may be a power supply such as an alternator or a converter.

[0118] In the above embodiment, the power storage unit is an electric double layer capacitor, but the power storage unit is not limited to an electric double layer capacitor and may be other types of power storage unit such as a lithium ion capacitor or a lithium ion battery.

[0119] In the above embodiment, the backup control device performs backup operation when the power supply from the power supply unit is cut off, but the backup control device may also perform backup operation to supply power from the storage unit in a specified state where the power supply is not completely cut off.

[0120] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims. [Explanation of symbols]

[0121] 1: Backup control unit 11, 12, 13, 14, 15, 21, 22, 23, 24, 25: Conductive path 30: Supply circuit 31: 1st supply circuit 31A: First conversion unit 31B: Switching element 31C: First drive unit 32: 2nd supply circuit 32A: Second conversion unit 32B: Switching element 32C: Switching element 32D: Second drive unit 33: Switching element 33A: Dio Do 3 4: First voltage detection unit 35: Second voltage detection unit 41: First control section (control section) 42: Second control section (control section) 51: First detection unit 52: Second detection unit 71: First storage unit 72: Second storage unit 80: Power line 81A,81B,81C,81D,81E,81F: Power line 90: Power supply section 91,92: Load 93: Load (common load, 2nd load) 94: Load (1st load) 95: Load (1st load) 100: Automotive power supply systems 101: First storage unit (base unit) 102: Second storage unit (extension unit) 111: First conductive path 111A: Diode 111C: Conductive part 111D: Conductive part 112: Second conductive path 112A: Diode 112C: Conductive part 112D: Conductive part 113: Third Conduction Path 200: Automotive power supply systems 234: Current detection section 300: Automotive power supply system 400: Automotive power supply system 433: Switching element 433A: Diode 500: Automotive power supply system 511: First Conductive Path 512: Second conductive path 513: Third Conduction Path 530: Supply circuit 533: Switching section 534: Conductive Path 535: Diode 536: Diode

Claims

1. An in-vehicle backup control device is used in an in-vehicle power supply system including a power supply unit and a power storage unit, and performs a backup operation of outputting power to the load based on power from the power storage unit when a predetermined external condition occurs in which power supply from the power supply unit to the load is cut off or reduced, a first supply circuit capable of outputting power generated by a first power storage unit, which is one of the power storage units, to a common load via a first conduction path; a second supply circuit capable of outputting power generated by a second power storage unit that is one of the power storage units to the common load via a second conduction path; a control unit that causes the first supply circuit and the second supply circuit to perform the backup operation when the external state is in the abnormal state; and the second supply circuit supplies power based on the second power storage unit to one or more first loads and one or more second loads; the control unit performs predetermined priority control in the external state to prioritize a first backup operation in which power based on the second power storage unit is supplied to the first load over a second backup operation in which power based on the second power storage unit is supplied to the second load; a third conductive path which is a path for outputting power to the common load and through which power is supplied from the first conductive path and the second conductive path; the first supply circuit includes a first switching element that is provided in the first conductive path, enables current to flow from the first power storage unit to the third conductive path when in an ON state, and blocks current to flow from the first power storage unit to the third conductive path when in an OFF state; the second supply circuit includes a second switching element that is provided in the second conductive path, that enables current to flow from the second power storage unit to the third conductive path when in an ON state, and that cuts off current flow from the second power storage unit to the third conductive path when in an OFF state; the control unit includes a first control unit that controls the first supply circuit and a second control unit that controls the second supply circuit; the first control unit and the second control unit are capable of communicating with each other, a backup control device for an automobile, wherein, during the second backup operation, the first control unit turns the first switching element off, while the second control unit turns the second switching element on, thereby applying a voltage based on the second storage unit to the third conductive path via the second conductive path; and, during the first backup operation, the first control unit turns the first switching element on, while the second control unit turns the second switching element off, thereby applying a voltage based on the first storage unit to the third conductive path via the first conductive path.

2. An in-vehicle backup control device is used in an in-vehicle power supply system including a power supply unit and a power storage unit, and performs a backup operation of outputting power to the load based on power from the power storage unit when a predetermined external condition occurs in which power supply from the power supply unit to the load is cut off or reduced, a first supply circuit capable of outputting power generated by a first power storage unit, which is one of the power storage units, to a common load via a first conduction path; a second supply circuit capable of outputting power generated by a second power storage unit that is one of the power storage units to the common load via a second conduction path; a control unit that causes the first supply circuit and the second supply circuit to perform the backup operation when the external state is in the abnormal state; and the second supply circuit supplies power based on the second power storage unit to one or more first loads and one or more second loads; the control unit performs predetermined priority control in the external state to prioritize a first backup operation in which power based on the second power storage unit is supplied to the first load over a second backup operation in which power based on the second power storage unit is supplied to the second load; a third conductive path that is a path for outputting power to the common load and through which power is supplied from the second conductive path; a diode provided between the first conductive path and the third conductive path, the anode of which is electrically connected to the first conductive path side and the cathode of which is electrically connected to the third conductive path side; and the first supply circuit includes a first conversion unit that increases or decreases an input voltage based on power from the first power storage unit and applies an output voltage to the first conduction path; the second supply circuit includes a second conversion unit that increases or decreases an input voltage based on power from the second power storage unit and applies an output voltage to the second conduction path; The control unit controls the output from the first conversion unit to the first conductive path and the output from the second conversion unit to the second conductive path so that, during the priority control, power based on the second storage unit is supplied to the third conductive path via the second conductive path and power based on the first storage unit is cut off by the diode.

3. a first voltage detection unit that detects a voltage of the first conductive path; a second voltage detection unit that detects a voltage of the third conductive path; and 3. The vehicle-mounted backup control device according to claim 2, wherein, during the priority control, the control unit controls the first conversion unit so that a voltage based on the first storage unit is applied to the first conduction path, controls the second conversion unit so that a voltage based on the second storage unit is applied to the third conduction path, and controls the first conversion unit and the second conversion unit based on voltage detection results by the first voltage detection unit and the second voltage detection unit so that the voltage of the third conduction path is maintained at a voltage that blocks current from flowing from the first conduction path to the third conduction path.

4. a current detection unit that detects a current in the first conductive path; 3. The vehicle backup control device according to claim 2, wherein, during the priority control, the control unit controls the first conversion unit so that a voltage based on the first storage unit is applied to the first conduction path, controls the second conversion unit so that a voltage based on the second storage unit is applied to the third conduction path, and controls the first conversion unit and the second conversion unit based on a detection result by the current detection unit so that a current flowing from the first conduction path toward the diode approaches zero or less.

5. the control unit includes a first control unit that controls the first supply circuit and a second control unit that controls the second supply circuit; the first control unit and the second control unit are capable of communicating with each other, 3. The vehicle backup control device according to claim 2, wherein, during the priority control, the first control unit controls the first conversion unit so that a voltage based on the first storage unit is applied to the first conduction path, the second control unit controls the second conversion unit so that a voltage based on the second storage unit is applied to the third conduction path, and the first control unit and the second control unit control the first conversion unit and the second conversion unit so that the voltage of the third conduction path is maintained at a voltage that blocks current from flowing from the first conduction path to the third conduction path.

6. An in-vehicle backup control device is used in an in-vehicle power supply system including a power supply unit and a power storage unit, and performs a backup operation of outputting power to the load based on power from the power storage unit when a predetermined external condition occurs in which power supply from the power supply unit to the load is cut off or reduced, a first supply circuit capable of outputting power generated by a first power storage unit, which is one of the power storage units, to a common load via a first conduction path; a second supply circuit capable of outputting power generated by a second power storage unit that is one of the power storage units to the common load via a second conduction path; a control unit that causes the first supply circuit and the second supply circuit to perform the backup operation when the external state is in the abnormal state; and the second supply circuit supplies power based on the second power storage unit to one or more first loads and one or more second loads; the control unit performs predetermined priority control in the external state to prioritize a first backup operation in which power based on the second power storage unit is supplied to the first load over a second backup operation in which power based on the second power storage unit is supplied to the second load; the priority control includes limiting control that stops supply of power based on the second power storage unit to the second load when the second power storage unit is in a predetermined state; The control unit performs the limit control in accordance with the predetermined state until a cumulative operation time of the first load based on the first backup operation reaches a specified time.

7. 7. The vehicle backup control device according to claim 6, wherein the predetermined state is a state in which an open-circuit voltage of the second power storage unit reaches or exceeds a cut-off voltage set by a predetermined determination method.

8. The vehicle backup control device according to claim 1 , wherein the common load is the second load.

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