Vehicle-mounted backup power supply control device and vehicle-mounted backup power supply device

Abstract

The present invention realizes a structure that can improve the reliability of backup operation more simply. A vehicle-mounted backup power supply control device (1) comprises: a first control unit (22) that causes a charge-discharge unit (10) (first discharge unit) to perform a first discharge operation when power supply based on a power supply unit (90) becomes in a failed state; and a second control unit (24) that causes a second discharge unit (12) to perform a second discharge operation when power supply based on a power supply unit (90) becomes in a failed state and at least the first discharge performed by the charge-discharge unit (10) is in an abnormal state.

Description

Technical Field

[0001] The invention relates to a vehicle-mounted backup power supply control device and a vehicle-mounted backup power supply device. Background Art

[0002] In the past, a backup power supply device for vehicle use is known. For example, the backup power supply device (backup power supply device 8) described in Patent Document 1 includes a power input unit 9, an output unit 10, a capacitor unit 11, a charging circuit unit 12, a boost circuit unit 13, and a control unit 21. In the backup power supply device 8, according to an instruction from the control unit 21, the charging circuit unit 12 uses the power supplied from the power input unit 9 to pre-charge the capacitor unit 11. And, based on the situation that the voltage of the power input unit 9 becomes lower than a threshold value, according to an instruction from the control unit 21, the charging voltage accumulated in the capacitor unit 11 is boosted by the boost circuit unit 13 and output from the output unit 10.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-235174 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, since the backup power supply device 8 of Patent Document 1 has only a single backup path, if a component constituting the backup path or a related component fails (breaks down, etc.), the backup operation may not be performed at a necessary time.

[0008] The present invention has been made to solve at least one of the above-mentioned problems, and an object of the present invention is to more simply realize a structure capable of improving the reliability of a backup operation.

[0009] Technical solutions to solve problems

[0010] A vehicle-mounted backup power supply control device according to a first aspect of the present invention controls the supply of power from the power storage unit in a vehicle-mounted power supply system including a power supply unit and a power storage unit, wherein power from the power supply unit is supplied to a power supply target via a power path, wherein the vehicle-mounted backup power supply control device has:

[0011] a first discharge unit that performs a first discharge operation of supplying a discharge current based on the power supplied from the power storage unit to the power path via a first discharge path;

[0012] a second discharge unit that performs a second discharge operation of supplying a discharge current based on the power supplied from the power storage unit toward the power supply destination via a second discharge path different from the first discharge path;

[0013] a first control unit that, when power supply from the power supply unit becomes a failure state, causes the first discharge unit to perform the first discharge operation; and

[0014] The second control unit controls the second discharge unit to perform the second discharge operation when the power supply from the power supply unit becomes the failed state and when at least the first discharge performed by the first discharge unit is in an abnormal state.

[0015] A vehicle-mounted backup power supply device according to a second aspect of the present invention comprises:

[0016] A vehicle-mounted backup power supply control device according to the first aspect; and

[0017] The power storage unit.

[0018] Effects of the Invention

[0019] The vehicle-mounted backup power supply control device of the first embodiment causes the first discharge unit to perform a first discharge operation when the power supply from the power supply unit fails. If the first discharge operation is performed, the power from the storage unit can be supplied to the power path, and the power supply to the power supply object can be continued.

[0020] Furthermore, in the vehicle-mounted backup power supply control device of the first embodiment, even if the first discharge operation performed by the first discharge unit becomes an abnormal state, the second discharge unit can be made to perform the second discharge operation to supply power to the power supply object through a path different from that of the first discharge unit. Therefore, the reliability of the backup operation is significantly improved. Furthermore, when the second discharge unit performs the backup operation, the power storage unit shared with the case where the first discharge unit performs the backup operation can also be used as a power supply source, so that the increase in the number of components can be suppressed and the above-mentioned effect can be obtained.

[0021] As described above, according to the vehicle-mounted backup power supply control device of the first aspect, it is possible to more simply implement a configuration capable of improving the reliability of the backup operation.

[0022] According to the vehicle-mounted backup power supply device of the second aspect, it is possible to achieve the same effects as the vehicle-mounted backup power supply control device of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is a circuit diagram schematically showing a vehicle-mounted power supply system including a backup power supply control device according to the first embodiment.

[0024] Figure 2 1 is a flowchart showing the flow of the second discharge control in the first embodiment.

[0025] Figure 3 This is a timing chart showing a flow when the backup by the charging and discharging unit in the first embodiment is performed normally.

[0026] Figure 4 This is a timing chart showing a flow when backup by the charging and discharging unit in the first embodiment is not performed normally.

[0027] Figure 5 This is a circuit diagram schematically showing a vehicle-mounted power supply system including a backup power supply control device according to a second embodiment.

[0028] Figure 6 This is a timing chart showing a flow when backup by the charging and discharging unit in the second embodiment is not performed normally.

[0029] Figure 7 This is a circuit diagram schematically showing a vehicle-mounted power supply system including a backup power supply control device according to a third embodiment. DETAILED DESCRIPTION

[0030] Preferred embodiments of the present invention will be described.

[0031] The first control unit and the second control unit may be configured to operate independently of each other.

[0032] According to this configuration, even when the first discharge operation is not normally performed due to an abnormality caused by the first control unit (eg, a failure of the first control unit), the second control unit can independently control the second discharge unit to perform the second discharge operation.

[0033] A switch unit that switches between an on state and an off state may be provided at a position in the power path that is closer to the power supply target than the connection portion of the first discharge path. Furthermore, the switch unit may be configured to allow power supply from the power supply unit to the power supply target in the on state, and to cut off power supply from the power supply unit to the power supply target in the off state. The second discharge path may be electrically connected to a position in the power path that is closer to the power supply target than the switch unit, and the second control unit may be configured to switch the switch unit to an off state when the power supply based on the power supply unit becomes a failure state, at least when the first discharge performed by the first discharge unit is an abnormal state.

[0034] According to this structure, when the first discharge operation becomes abnormal, the switch unit can be switched to the off state to electrically disconnect the power supply unit side of the switch unit in the power path from the power supply target side. Therefore, when the discharge current is supplied to the power supply target side of the switch unit in the power path through the second discharge operation, the discharge current can be stably supplied without being affected by the power supply unit side of the switch unit in the power path.

[0035] A capacitor may be provided which is electrically connected to the power path and is charged based on the power supplied from the power supply unit.

[0036] According to this structure, when an open circuit fault or the like occurs on the power supply side and the power supply is interrupted, power can be immediately supplied from the capacitor to the power supply object. Therefore, the possibility of maintaining power supply to the power supply object is increased during the period from the interruption of power supply by the power supply unit to the start of the backup operation by the first discharge unit or the second discharge unit.

[0037] It may also include a low-dropout regulator having one end electrically connected to the power storage unit and the other end electrically connected to the power path, and when the power supply based on the power supply unit becomes a failure state, the input voltage based on the charging voltage of the power storage unit is stepped down and an output voltage is applied to the power path.

[0038] According to this structure, when an open circuit fault or the like occurs on the power supply side and the power supply is interrupted, power can be immediately supplied to the power supply object through the low-dropout voltage regulator. Therefore, the possibility of maintaining power supply to the power supply object is increased from the interruption of power supply based on the power supply unit to the start of the standby operation performed by the first discharge unit or the second discharge unit. In addition, during the period when the voltage of the power path exceeds the specified voltage (the voltage that becomes the potential difference for starting the step-down operation by the low-dropout voltage regulator), the step-down operation based on the low-dropout voltage regulator is not performed, so during this period, the discharge of the storage unit based on the low-dropout voltage regulator can be suppressed.

[0039] The second control unit may operate so as to cause the second discharge unit to start the second discharge operation before the first discharge unit starts the first discharge operation under the control of the first control unit when the power supply from the power supply unit fails.

[0040] According to this configuration, after the failure state occurs, the backup operation by the second discharge unit can be started before the first discharge unit starts the first discharge operation. Therefore, compared with the configuration in which the backup operation is performed only by the first discharge unit, the time lag from the occurrence of the failure state to the start of the backup operation can be further shortened.

[0041] The first discharge unit may also be a voltage conversion unit that steps up or steps down an input voltage corresponding to the charging voltage of the power storage unit and applies a specified output voltage to the first discharge path. The second discharge unit may also be a switch that allows power to be supplied from the power storage unit to the power supply object when in the on state, and cuts off power from the power storage unit to the power supply object when in the off state. The second control unit may also operate in the following manner: when the power supply based on the power supply unit becomes a failure state, the second discharge unit starts the second discharge operation, and when the first discharge unit starts the first discharge operation during the second discharge operation, the second discharge operation is stopped.

[0042] According to this structure, when a failure state occurs, a backup operation can be performed to output a predetermined output voltage through the first discharge unit. Furthermore, if the second discharge operation performed by the second discharge unit is started before the first discharge unit starts the first discharge operation, the time lag from the occurrence of the failure state to the start of the backup operation can be further shortened, and if the second discharge operation is stopped when the first discharge operation is started after the second discharge operation is started, the subsequent backup operation can be unified with the first discharge operation.

[0043] Hereinafter, examples embodying the present invention will be described.

[0044] <Example 1>

[0045] Figure 1 The circuit diagram of a vehicle-mounted power supply system 100 having a vehicle-mounted backup power supply control device 1 (hereinafter also referred to as "backup power supply control device 1") according to the first embodiment is schematically shown. The vehicle-mounted power supply system 100 includes: a power supply unit 90 as a main power supply for supplying power to a load 94 (power supply target); a power storage unit 92 that serves as a power supply source at least when the power supply from the power supply unit 90 is interrupted; and a backup power supply control device 1 having a function of quickly discharging from the power storage unit 92 when the power supply from the power supply unit 90 is interrupted. The vehicle-mounted power supply system 100 is configured as a system that supplies power to the load 94 using the power supply unit 90 or the power storage unit 92 as a power supply source. In addition, a vehicle-mounted backup power supply device 2 is configured in a form including the backup power supply control device 1 and the power storage unit 92.

[0046] The vehicle-mounted power supply system 100 is configured such that when the power supply from the power supply unit 90 is in a normal state, power is supplied from the power supply unit 90 to the load 94 via the first conductive path 71, the second conductive path 72, and the third conductive path 73 provided in the backup power supply control device 1. In this configuration, "when the power supply from the power supply unit 90 is in a normal state" means that the output voltage of the power supply unit 90 exceeds the "prescribed value (first threshold voltage Vth1)", and specifically, the voltage applied to the first conductive path 71 based on the output voltage of the power supply unit 90 exceeds the "prescribed value (first threshold voltage Vth1)".

[0047] The backup power supply control device 1 is a device that uses the storage unit 92 charged based on the power supply from the power supply unit 90 as a backup power supply and controls the discharge operation of the storage unit 92. The backup power supply control device 1 has the following structure: it has a charging and discharging unit 10 (first discharging unit) and a second discharging unit 12, and the discharge and discharge stop of the storage unit 92 are switched by the charging and discharging unit 10 or the second discharging unit 12, and the power from the storage unit 92 can be supplied to the load 94 during the discharge.

[0048] The power supply unit 90 functions as a main power supply, and is configured as a known vehicle-mounted battery such as a lead-acid battery, for example. The high-potential side terminal of the power supply unit 90 is electrically connected to the first wiring unit 81, and the power supply unit 90 applies a predetermined output voltage to the first wiring unit 81. The output voltage of the power supply unit 90 when fully charged is set to a value greater than 0V.

[0049] The power storage unit 92 functions as an auxiliary power source, and is composed of a known power storage unit such as an electric double layer capacitor (EDLC). The power storage unit 92 is electrically connected to the charge and discharge unit 10 via the fourth conductive path 74, and is charged by the charge and discharge unit 10. In addition, the power storage unit 92 is electrically connected to the charge and discharge unit 10 and the second discharge unit 12, respectively, and is discharged by the charge and discharge unit 10 or the second discharge unit 12. In addition, in Embodiment 1, the output voltage of the power storage unit 92 when fully charged is greater than 0V and less than the output voltage of the power supply unit 90 when fully charged. However, the output voltage of the power storage unit 92 when fully charged may be the same as the output voltage of the power supply unit 90 when fully charged, or may be greater than the output voltage of the power supply unit 90 when fully charged.

[0050] The load 94 corresponds to an example of an object to which power is supplied, and is constituted as a known on-vehicle electrical component. The load 94 is electrically connected to the backup power supply control device 1 via the second wiring section 82. A preferred example of the load 94 is an electrical component that requires power supply even when the power supply from the power supply section 90 becomes a failure state, such as an ECU, an actuator, etc. in a shift-by-wire system or an advanced driver assistance system (ADAS). The load 94 operates based on the power supplied from the power supply section 90 in the above-mentioned normal state, and operates based on the power supplied from the power storage section 92 when the power supply from the power supply section 90 is a failure state.

[0051] The backup power supply control device 1 mainly includes an input cutoff section 14, an output cutoff section 16, a control section 20, and the like in addition to the above-mentioned charging and discharging section 10 and the second discharging section 12.

[0052] The input cutoff unit 14 is interposed between the power supply unit 90 and the load 94, and switches between a permitted state in which power supply from the power supply unit 90 to the load 94 is permitted and a prohibited state in which power supply from the power supply unit 90 to the load 94 is prohibited. For example, the input cutoff unit 14 is configured as a well-known switching element such as a FET (Field Effect Transistor). The input cutoff unit 14 is electrically connected to the first conductive path 71 at the end on the power supply unit 90 side, and is electrically connected to the power supply unit 90 via the first conductive path 71. The input cutoff unit 14 is electrically connected to the third conductive path 73 at the end on the load 94 side, and is electrically connected to the load 94 via the third conductive path 73. The input cutoff unit 14 is controlled by the first control signal SG1 provided from the control unit 20, and is switched to the permitted state by the first control signal SG1 provided as the permitted signal, and is switched to the prohibited state by the first control signal SG1 provided as the prohibited signal.

[0053] The output cutoff section 16 corresponds to an example of a switch section, and is located between the power supply section 90 and the load 94 at a position closer to the load 94 side than the input cutoff section 14, and switches between a permitted state in which power supply from the power supply section 90 side to the load 94 side is permitted and a prohibited state in which power supply from the power supply section 90 side to the load 94 side is prohibited, and is constituted by a well-known switch element such as a FET (Field Effect Transistor). The output cutoff section 16 is electrically connected to the third conductive path 73 at the end on the input cutoff section 14 side (power supply section 90 side), and is electrically connected to the input cutoff section 14 via the third conductive path 73. The output cutoff section 16 is electrically connected to the second conductive path 72 at the end on the load 94 side, and is electrically connected to the load 94 via the second conductive path 72. The output cutoff section 16 is controlled by the third control signal SG3 provided from the control section 20, and is switched to the permitted state by the third control signal SG3 provided as the permitted signal, and is switched to the prohibited state by the third control signal SG3 provided as the prohibited signal. In this configuration, the first conductive path 71 , the second conductive path 72 , and the third conductive path 73 constitute the electric power path 70 .

[0054] The charge-discharge section 10 is equivalent to an example of a first discharge section, and is a circuit capable of performing a first discharge operation, the first discharge operation being an operation of supplying a discharge current based on the power supply from the power storage section 92 to the power path 70 via the first discharge path 61, and a first stop operation being an operation of stopping the discharge current via the first discharge path 61. The first discharge path 61 is a conductive path between the charge-discharge section 10 and the third conductive path 73. The charge-discharge section 10 is configured as, for example, a known charge-discharge circuit, and more specifically, as a known voltage conversion circuit such as a buck-boost type DCDC converter. The charge-discharge section 10 is interposed between the power supply section 90 and the power storage section 92, and functions as a charging section that charges the power storage section 92 using the power supplied from the power supply section 90. In addition, the charge-discharge section 10 is interposed between the power storage section 92 and the load 94, and functions as a discharge section that discharges the power storage section 92 and supplies power to the load 94 side. The end of the charging and discharging section 10 on the power storage section 92 side is electrically connected to the fourth conductive path 74, and the charging and discharging section 10 is electrically connected to the power storage section 92 via the fourth conductive path 74. The end of the charging and discharging section 10 on the load 94 side (power supply section 90 side) is electrically connected to the third conductive path 73, and the charging and discharging section 10 is electrically connected to the input cutoff section 14 and the output cutoff section 16 respectively via the third conductive path 73. That is, the input cutoff section 14 is interposed between the power supply section 90 and the charging and discharging section 10, and the output cutoff section 16 is interposed between the charging and discharging section 10 and the load 94.

[0055] The charge-discharge unit 10 can perform a charging operation for charging the power storage unit 92 based on the power from the power supply unit 90, a charge stop operation for stopping the charging of the power storage unit 92, a discharge operation for discharging the power storage unit 92 (a first discharge operation), and a discharge stop operation for stopping the discharge of the power storage unit 92 (a first stop operation). The charge-discharge unit 10 is controlled by the second control signal SG2 provided from the control unit 20, and performs a charging operation by the second control signal SG2 provided as a charging signal, performs a charge stop operation by the second control signal SG2 provided as a charging stop signal, performs a discharge operation by the second control signal SG2 provided as a discharge signal, and performs a discharge stop operation by the second control signal SG2 provided as a discharge stop signal.

[0056] When the second control signal SG2 as a charging signal is supplied, the charge-discharge unit 10 performs a voltage conversion operation of stepping up or down the power supply voltage input from the power supply unit 90 via the first conductive path 71, the input cutoff unit 14, and the third conductive path 73, and applies the stepped-up or stepped-down voltage to the power storage unit 92 via the fourth conductive path 74. When the second control signal SG2 as a charging stop signal is supplied, the charge-discharge unit 10 stops the above-mentioned charging operation and puts the third conductive path 73 and the fourth conductive path 74 into a non-conductive state.

[0057] When the second control signal SG2 serving as a discharge signal is supplied, the charge-discharge unit 10 performs a discharge operation to output a target voltage determined to the third conduction path 73 or the second conduction path 72 based on the input voltage (output voltage from the power storage unit 92) applied to the fourth conduction path 74. When the second control signal SG2 serving as a discharge stop signal is supplied, the charge-discharge unit 10 stops the above-described discharge operation and puts the third conduction path 73 and the fourth conduction path 74 into a non-conductive state.

[0058] The second discharge section 12 is a discharge section different from the charge and discharge section 10 (first discharge section), and is a circuit capable of performing a second discharge operation, the second discharge operation being an operation of supplying a discharge current based on the power supply from the power storage section 92 to a power supply target via a second discharge path 62 different from the first discharge path 61, and a second stop operation being an operation of stopping the discharge current via the second discharge path 62. The second discharge section 12 is configured, for example, as a known discharge circuit, and more specifically, as a known switch (for example, a known semiconductor switch element such as FET). The second discharge section 12 is interposed between the power storage section 92 and the load 94, and functions as a discharge section that discharges the power storage section 92 and supplies power to the load 94 side. The end of the second discharge section 12 on the power storage section 92 side is electrically connected to the fourth conductive path 74, and the second discharge section 12 is electrically connected to the power storage section 92 via the fourth conductive path 74. An end portion of the second discharge section 12 on the load 94 side is electrically connected to the second conductive path 72 , and the second discharge section 12 is electrically connected to the load 94 via the second conductive path 72 .

[0059] The second discharge unit 12 can perform a discharge operation (second discharge operation) for discharging the storage unit 92 and a discharge stop operation (second stop operation) for stopping the discharge of the storage unit 92. The second discharge unit 12 is in a permitted state for permitting the supply of power from the storage unit 92 to the load 94 during the discharge operation, and is in a prohibited state for prohibiting the supply of power from the storage unit 92 to the load 94 during the discharge stop operation. The second discharge unit 12 is controlled by the fourth control signal SG4 supplied from the control unit 20, and performs the discharge operation by being supplied with the fourth control signal SG4 as a discharge signal, and performs the discharge stop operation by being supplied with the fourth control signal SG4 as a discharge stop signal.

[0060] The control unit 20 is configured to include, for example, a well-known microcontroller, etc. The control unit 20 can switch the input cutoff unit 14 to any state of the enabled state and the disabled state by providing the first control signal SG1 to the input cutoff unit 14. In addition, the control unit 20 can switch the output cutoff unit 16 to any state of the enabled state and the disabled state by providing the third control signal SG3 to the output cutoff unit 16.

[0061] The control unit 20 can make the charge-discharge unit 10 perform any of the charging operation, the charge stop operation, the discharge operation, and the discharge stop operation by providing the second control signal SG2 to the charge-discharge unit 10. In addition, the control unit 20 can detect the situation that the power supply from the power supply unit 90 becomes a failure state, and based on the detection of the above-mentioned failure state, can control the charge-discharge unit 10 to discharge the power storage unit 92. In addition, the control unit 20 monitors the voltage of the first conductive path 71, and determines that the above-mentioned failure state is reached when the voltage of the first conductive path 71 becomes less than the prescribed first threshold voltage Vth1. That is, in this structure, the situation that the voltage of the first conductive path 71 becomes less than the prescribed first threshold voltage Vth1 is equivalent to an example of "the situation that the power supply based on the power supply unit 90 becomes a failure state". The first threshold voltage Vth1 is a value greater than 0V and less than the output voltage of the power supply unit 90.

[0062] The control unit 20 can make the second discharge unit 12 perform any of the discharge operation and the discharge stop operation by providing the fourth control signal SG4 to the second discharge unit 12. In addition, when the control unit 20 detects the above-mentioned failure state, it can determine whether there is an abnormality that the discharge of the storage unit 92 by the charge and discharge unit 10 cannot be performed. And, when it is determined that there is such an abnormality, the control unit 20 can control the second discharge unit 12 to discharge the storage unit 92. The second discharge control.

[0063] The control unit 20 includes a first control unit 22 and a second control unit 24 that operate independently. The first control unit 22 includes a voltage detection unit that detects a voltage applied to the first conductive path 71 (the voltage of the first conductive path 71) based on the output voltage of the power supply unit 90, and a voltage detection unit that detects a charge voltage of the power storage unit 92 (the voltage of the fourth conductive path 74), and can obtain a voltage applied to the first conductive path 71 (the voltage of the first conductive path 71) and a charge voltage of the power storage unit 92 (the voltage of the fourth conductive path 74) based on the output voltage of the power supply unit 90. The first control unit 22 controls the charge and discharge unit 10 and the input cutoff unit 14, and can perform the above-mentioned first discharge control. The first control unit 22 is configured to be able to operate even when the second control unit 24 is no longer operating due to a malfunction or the like.

[0064] The second control unit 24 includes a voltage detection unit that detects a voltage applied to the first conductive path 71 (the voltage of the first conductive path 71) based on the output voltage of the power supply unit 90, and a voltage detection unit that detects a voltage of the third conductive path 73, and can obtain a voltage applied to the first conductive path 71 (the voltage of the first conductive path 71) and a voltage of the third conductive path 73 based on the output voltage of the power supply unit 90. The second control unit 24 controls the second discharge unit 12 and the output cutoff unit 16, and can perform the above-mentioned second discharge control. The second control unit 24 is configured to be able to operate even when the first control unit 22 is no longer operating due to a malfunction or the like.

[0065] The first control unit 22 and the second control unit 24 can be respectively configured as a microcontroller, or an FPGA (field programmable gate array), or can be configured by other hardware circuits. For example, the first control unit 22 and the second control unit 24 can also be respectively configured as a single chip microcomputer. In addition, in this embodiment, an example in which the first control unit 22 is configured as a microcontroller and the second control unit 24 is configured as a hardware circuit is described.

[0066] Next, the operation of the backup power supply control device 1 will be described.

[0067] When the power supply from the power supply unit 90 is in a normal state, the input cutoff unit 14 and the output cutoff unit 16 are both in the enabled state, and power is supplied to the load 94 via the first conductive path 71, the third conductive path 73, and the second conductive path 72. In addition, the second discharge unit 12 is in the disabled state.

[0068] At this time, the first control unit 22 (control unit 20) monitors the charging voltage of the power storage unit 92 (the voltage of the fourth conductive path 74), and when the charging voltage of the power storage unit 92 is less than a predetermined value that requires charging, the second control signal SG2 serving as a charging signal is output to the charge-discharge unit 10. Thus, the charge-discharge unit 10 is controlled so that the charge-discharge unit 10 performs a charging operation. Furthermore, when the charging voltage of the power storage unit 92 reaches a predetermined target voltage, the second control signal SG2 serving as a charging stop signal is output to the charge-discharge unit 10, thereby controlling the charge-discharge unit 10 so that the charge-discharge unit 10 performs a charging stop operation.

[0069] Furthermore, the first control unit 22 (control unit 20) repeatedly determines whether the power supply from the power supply unit 90 has become a failure state. More specifically, the voltage of the first conductive path 71 is monitored, and it is repeatedly determined whether the voltage of the first conductive path 71 has become a first threshold voltage Vth1 or less. When the voltage of the first conductive path 71 has become a first threshold voltage Vth1 or less, it is detected that the power supply from the power supply unit 90 has become a failure state.

[0070] When the first control unit 22 (control unit 20) detects the failure state, it outputs the first control signal SG1, which is a prohibition signal, to the input cutoff unit 14, and outputs the second control signal SG2, which is a discharge signal, to the charge-discharge unit 10. That is, the first control unit 22 (control unit 20) controls the input cutoff unit 14 to be in a prohibition state, and controls the charge-discharge unit 10 to discharge the power storage unit 92. Thus, power is supplied from the power storage unit 92 to the load 94, and backup by the charge-discharge unit 10 is performed.

[0071] However, when the power supply from the power supply unit 90 fails, the backup by the charge-discharge unit 10 may not be performed normally. The reasons for this may be, for example, that the charge-discharge unit 10 does not operate normally due to a failure, or the input cutoff unit 14 maintains the enabled state due to a failure and cannot be applied to the third conductive path 73, or that the first control unit 22 cannot operate the charge-discharge unit 10 and the input cutoff unit 14 normally due to a failure. In order to cope with such a situation, the following countermeasures are taken in the backup power supply control device 1.

[0072] The second control unit 24 (control unit 20) repeatedly executes the following steps after the start switch (for example, the ignition switch) is turned on until the start switch (for example, the ignition switch) is turned off. Figure 2 The second discharge control is shown.

[0073] In step S10, the second control unit 24 obtains the voltage of the first conductive path 71 and the voltage of the third conductive path 73. Then, it is determined whether the power supply from the power supply unit 90 has become a failure state. Specifically, in step S12, it is determined whether the voltage of the first conductive path 71 is less than the first threshold voltage Vth1. When the voltage of the first conductive path 71 is not less than the first threshold voltage Vth1 (step S12: No), it is determined that the power supply from the power supply unit 90 is normally performed. Then, in step S18, the third control signal SG3 is output to the output cutoff unit 16 as an enable signal, and the fourth control signal SG4 is output to the second discharge unit 12 as a disable signal. That is, the second control unit 24 (control unit 20) controls to maintain the output cutoff unit 16 in the enable state, and controls to maintain the second discharge unit 12 in the disable state.

[0074] After that, if the failure state is reached, the voltage of the first conductive path 71 becomes less than the first threshold voltage Vth1, so in step S12, it is determined that the voltage of the first conductive path 71 is less than the first threshold voltage Vth1 (step S12: Yes), and the failure state is determined. When the failure state is determined (when the voltage of the first conductive path 71 is less than the first threshold voltage Vth1), the second control unit 24 (control unit 20) determines whether there is an abnormality that the discharge of the storage unit 92 by the charging and discharging unit 10 cannot be performed. Specifically, the second control unit 24 determines in step S14 whether the voltage of the third conductive path 73 is less than the second threshold voltage Vth2. The second threshold voltage Vth2 is the same as the first threshold voltage Vth1 in this embodiment.

[0075] In step S14, when it is determined that the voltage of the third conductive path 73 is not lower than the second threshold voltage Vth2 (step S14: No), it is determined that the backup by the charge and discharge unit 10 is normally performed. Then, in step S18, the third control signal SG3 is output to the output cutoff unit 16 as an enable signal, and the fourth control signal SG4 is output to the second discharge unit 12 as a discharge stop signal. That is, the second control unit 24 (control unit 20) controls to maintain the output cutoff unit 16 in the enable state, and controls to maintain the second discharge unit 12 in the disable state.

[0076] On the other hand, when the second control unit 24 (control unit 20) determines in step S14 that the voltage of the third conductive path 73 is less than or equal to the second threshold voltage Vth2 (step S14: Yes), it is determined that the backup by the charge-discharge unit 10 is not normally performed. That is, it is determined that there is an abnormality that the discharge of the storage unit 92 by the charge-discharge unit 10 cannot be performed. Then, in step S16, the third control signal SG3, which is a prohibition signal, is output to the output cutoff unit 16, and the fourth control signal SG4, which is a discharge signal, is output to the second discharge unit 12. That is, the second control unit 24 (control unit 20) controls the output cutoff unit 16 to the prohibition state, and controls the second discharge unit 12 in such a manner that the second discharge unit 12 discharges the storage unit 92. As a result, power is supplied from the storage unit 92 to the load 94, and the backup by the second discharge unit 12 is performed.

[0077] Next, use Figure 3 and Figure 4 The timing diagram illustrates the backup action of the backup power supply control device 1.

[0078] Figure 3 The operation in the case where the backup by the charging and discharging unit 10 is normally performed is illustrated.

[0079] When the power supply from the power supply unit 90 is in a normal state, the voltage of the first conductive path 71 is maintained at a voltage higher than the first threshold voltage Vth1. Therefore, the first control unit 22 outputs the first control signal SG1 as an enable signal to enable the input cutoff unit 14. In addition, the first control unit 22 monitors the charging voltage of the storage unit 92 (the output voltage of the fourth conductive path 74), and when the charging voltage of the storage unit 92 is less than the value required for charging, the first control unit 22 outputs the second control signal SG2 as a charging signal to charge the storage unit 92 by the charging and discharging unit 10, and when the charging voltage of the storage unit 92 reaches the target voltage, the second control signal SG2 as a charging stop signal is output to stop the charging operation performed by the charging and discharging unit 10.

[0080] In addition, when the power supply from the power supply unit 90 is in a normal state, the voltage of the first conductive path 71 is maintained at a voltage higher than the first threshold voltage Vth1, and the voltage of the third conductive path 73 is maintained at a voltage higher than the second threshold voltage Vth2. Therefore, the second control unit 24 outputs the third control signal SG3 as an enable signal and the fourth control signal SG4 as a discharge stop signal. Therefore, the output cutoff unit 16 is in an enable state, and the second discharge unit 12 performs a discharge stop operation.

[0081] Furthermore, the output voltage of the backup power supply control device 1 (the voltage of the second conductive path 72 ) is maintained at a voltage higher than any value of the first threshold voltage Vth1 and the second threshold voltage Vth2 .

[0082] After that, if the failure state is reached, the failure state is detected by the first control unit 22 and the second control unit 24 at the timing T1. The second control unit 24 that has detected the failure state further determines that the voltage of the third conductive path 73 is less than the second threshold voltage Vth2. That is, it is determined that there is an abnormality that the discharge of the storage unit 92 by the charging and discharging unit 10 cannot be performed. In this structure, the state in which the voltage of the third conductive path 73 is less than the second threshold voltage Vth2 in the failure state corresponds to an example of "a case in which the first discharge by the first discharge unit is an abnormal state". In addition, the second control unit 24 does not wait for the time required from the failure state to the start of the discharge by the charging and discharging unit 10, and immediately outputs the third control signal SG3 that becomes the prohibition signal and the fourth control signal SG4 that becomes the discharge signal at the timing T2. As a result, the second control unit 24 controls the output cutoff unit 16 to the prohibition state, and controls the second discharge unit 12 to discharge the storage unit 92.

[0083] On the other hand, the first control unit 22 outputs the first control signal SG1 which is a prohibition signal and the second control signal SG2 which is a discharge signal at the timing T3 based on the detection of the failure state. Thus, the first control unit 22 controls the input cutoff unit 14 to the prohibition state and controls the charge-discharge unit 10 to discharge the charge-discharge unit 10. As a result, the power storage unit 92 is discharged through the charge-discharge unit 10, so that the voltage of the third conductive path 73 becomes equal to or higher than the second threshold voltage Vth2.

[0084] Afterwards, the second control unit 24 receives the fact that the voltage of the third conductive path 73 becomes greater than the second threshold voltage Vth2, determines that there is no abnormality, and outputs the third control signal SG3 as an enable signal and the fourth control signal SG4 as a discharge stop signal at timing T4. Thus, the second control unit 24 controls the output cutoff unit 16 to the enable state and stops the discharge of the second discharge unit 12.

[0085] On the other hand, if the backup is not performed normally, Figure 4 The following actions are shown. Figure 4 In the example shown, it is assumed that the first control unit 22 fails and cannot output the control signal to the input cutoff unit 14 and the charging and discharging unit 10 .

[0086] The operation when the power supply from the power supply unit 90 is in a normal state is the same as the case where the backup is normally performed, and therefore the description thereof is omitted.

[0087] If the failure state is reached, the failure state is detected by the second control unit 24 at the timing T1. The second control unit 24 that has detected the failure state further determines that the voltage of the third conductive path 73 is less than the second threshold voltage Vth2. That is, it is determined that there is an abnormality that the discharge of the storage unit 92 by the charging and discharging unit 10 cannot be performed. In addition, when the second control unit 24 determines that the above-mentioned abnormality exists, it does not wait for the time required from the failure state to the first control unit 22 discharging the storage unit 92 through the charging and discharging unit 10, and immediately outputs the third control signal SG3 that becomes the prohibition signal and the fourth control signal SG4 that becomes the discharge signal at the timing T2. As a result, the second control unit 24 controls the output cutoff unit 16 to the prohibition state, and controls the second discharge unit 12 to discharge the storage unit 92.

[0088] On the other hand, the first control unit 22 fails, etc., and cannot detect the failure state. Or, although the failure state can be detected, an appropriate control signal cannot be output. As a result, the input cutoff unit 14 maintains the allowed state, and the charge-discharge unit 10 maintains the non-discharge state. Therefore, the voltage of the third conductive path 73 is maintained at a state below the second threshold voltage Vth2. Therefore, the second control unit 24 continues the discharge of the storage unit 92 by the second discharge unit 12. That is, when the backup based on the charge-discharge unit 10 is not normally performed, the backup based on the second discharge unit 12 is performed.

[0089] Next, the effects of the backup power supply control device 1 of this configuration will be described.

[0090] The backup power supply control device 1 of this structure makes the charge-discharge unit 10 (first discharge unit) perform the first discharge action when the power supply based on the power supply unit 90 becomes a failure state. If the first discharge action is performed, the power based on the storage unit 92 can be supplied to the power path 70, thereby continuing the power supply to the load 94 (power supply object). Moreover, in this structure, even if the first discharge action performed by the charge-discharge unit 10 (first discharge unit) becomes an abnormal state, the second discharge unit 12 can be made to perform the second discharge action to supply power to the load 94 in a different path from the charge-discharge unit 10 (first discharge unit). Therefore, the reliability of the backup action is significantly improved. Moreover, when the second discharge unit 12 performs the backup action, the storage unit 92 shared with the case of the charge-discharge unit 10 (first discharge unit) performing the backup action can also be used as the power supply source, so the increase in the number of components can be suppressed, and the above-mentioned effect can be obtained. In this way, according to the vehicle-mounted backup power supply control device 1 of this structure, a structure that can improve the reliability of the backup action can be more simply realized.

[0091] In the present structure, since the first control unit 22 and the second control unit 24 operate independently of each other, even if the first discharge operation is not performed normally due to an abnormality caused by the first control unit 22 (for example, a failure of the first control unit 22, etc.), the second control unit 24 can independently control the second discharge unit 12 to cause the second discharge unit 12 to perform the second discharge operation.

[0092] In this structure, an input cut-off section 14 that switches between an on state and an off state is provided on the power path 70 at a position closer to the power source section 90 than the connection section 73A of the first discharge path 61. Also, an output cut-off section 16 (switch section) that switches between an on state and an off state is provided on the power path 70 at a position closer to the load 94 (power supply target) than the connection section 73A. Also, the power path 70 includes a first conductive path 71 provided on the power source section 90 side than the input cut-off section 14, a second conductive path 72 provided on the load 94 (power supply target) side than the output cut-off section 16 (switch section), and a third conductive path 73 provided between the input cut-off section 14 and the output cut-off section 16 (switch section). Also, the input cut-off section 14 is configured to allow power supply from the first conductive path 71 side to the third conductive path 73 side in the on state, and to cut off power supply from the first conductive path 71 side to the third conductive path 73 side in the off state. The output cut-off section 16 (switch section) is configured to allow power supply from the third conductive path 73 side to the second conductive path 72 side in the on state, and to cut off power supply from the third conductive path 73 side to the second conductive path 72 side in the off state. The second discharge section 12 is electrically connected to the second conductive path 72, and the second control section 24 operates to switch the output cut-off section 16 (switch section) to the off state when the power supply based on the power supply section 90 becomes a failure state, at least when the first discharge operation performed by the charge and discharge section 10 (first discharge section) is an abnormal state. According to this structure, when the first discharge operation becomes an abnormal state, the output cut-off section 16 (switch section) can be switched to the off state to electrically cut off the third conductive path 73 and the second conductive path 72. Therefore, when the discharge current is supplied to the second conductive path 72 by the second discharge operation, the discharge current can be stably supplied without being affected by the third conductive path 73 side.

[0093] The second control unit 24 may also operate in the following manner: when the power supply by the power supply unit 90 becomes a failure state, before the charge and discharge unit 10 (first discharge unit) starts the first discharge operation according to the control of the first control unit 22, the second discharge unit 12 starts the second discharge operation. According to this structure, after the failure state occurs, the backup operation by the second discharge unit 12 can be started before the charge and discharge unit 10 (first discharge unit) starts the first discharge operation. Therefore, compared with the structure in which the backup operation is performed only by the charge and discharge unit 10 (first discharge unit), the time lag from the occurrence of the failure state to the start of the backup operation can be further shortened.

[0094] The charge and discharge section 10 (first discharge section) may also be a voltage conversion section that steps up or steps down an input voltage corresponding to the charging voltage of the storage section 92 and applies a predetermined output voltage to the first discharge path 61. The second discharge section 12 may also be a switch that allows power to be supplied from the storage section 92 to the load 94 (power supply target) when in the on state, and cuts off power to the load 94 (power supply target) from the storage section 92 when in the off state. The second control section 24 may also operate in the following manner: when the power supply based on the power supply section 90 becomes a failure state, the second discharge section 12 starts a second discharge operation, and when the charge and discharge section 10 (first discharge section) starts a first discharge operation during the second discharge operation, the second discharge operation is stopped. According to this structure, in the event of a failure state, a backup operation can be performed to output a predetermined output voltage through the charge and discharge section 10 (first discharge section). Furthermore, if the second discharge operation performed by the second discharge unit 12 is started before the charge and discharge unit 10 (first discharge unit) starts the first discharge operation, the time lag from the occurrence of the failure state to the start of the backup operation can be further shortened. If the second discharge operation is stopped when the first discharge operation is started after the second discharge operation is started, the subsequent backup operation can be unified with the first discharge operation.

[0095] <Example 2>

[0096] The backup power supply control device 201 of the second embodiment is a structure in which a capacitor 30 is added to the backup power supply control device 1 of the first embodiment, and the other structures are the same. In addition, the backup power supply device 202 of the second embodiment is formed into a structure including the backup power supply control device 201 and the power storage unit 92, and the vehicle-mounted power supply system 200 of the second embodiment is formed into a structure including the backup power supply device 202 and the power supply unit 90. In addition, the same reference numerals are attached to the same structures as the first embodiment, and the description thereof is omitted.

[0097] like Figure 5 As shown, the capacitor 30 is electrically connected to the power path 70 (second conductive path 72) between the power supply unit 90 and the load 94. When the power supply from the power supply unit 90 is in a normal state, the capacitor 30 is charged by the current supplied from the power supply unit 90 through the power path 70. On the other hand, when the above-mentioned failure state is reached, the capacitor 30 is discharged and the discharge current is supplied to the power path 70.

[0098] Next, the operation of the backup power supply control device 201 will be described. Figure 6 The timing chart of the operation when the discharge by the charge / discharge unit 10 is not performed in the failed state is illustrated.

[0099] The capacitor 30 is in a fully charged state before it becomes a failed state. The operation other than the capacitor 30 when the power supply from the power supply unit 90 is in a normal state is the same as that of the first embodiment, and thus the description thereof is omitted.

[0100] If the failure state is reached, power is not supplied from the power supply unit 90, and the voltage of the power supply path (the second conductive path 72) decreases, so the capacitor 30 discharges. Therefore, the voltage of the second conductive path 72 electrically connected to the capacitor 30 (the output voltage of the backup power supply control device 201) can be suppressed from decreasing. In addition, the second control unit 24 detects the failure state mentioned above during the period when power is supplied from the capacitor 30 to the load 94, and determines that there is an abnormality that the discharge of the storage unit 92 by the charging and discharging unit 10 cannot be performed, and outputs the third control signal SG3 that is a prohibition signal and the fourth control signal SG4 that is a discharge signal. That is, the second control unit 24 controls the output cutoff unit 16 to the prohibition state, and controls the second discharge unit 12 to discharge the storage unit 92.

[0101] Next, the effects of the backup power supply control device 201 of the second embodiment will be described.

[0102] In this structure, a capacitor 30 is provided which is electrically connected to the second conductive path 72 and is charged based on the power supplied from the power supply unit 90. According to this structure, when an open circuit fault or the like occurs on the power supply unit 90 side and the power supply from the power supply unit 90 is interrupted, power can be immediately supplied from the capacitor 30 to the load 94 (power supply target). Therefore, during the period from the interruption of the power supply based on the power supply unit 90 to the start of the standby operation by the charging and discharging unit 10 (first discharge unit) or the second discharge unit 12, the possibility of maintaining the power supply to the load 94 (power supply target) is increased. In addition, in the above structure, an example in which the capacitor 30 is connected to the second conductive path 72 is shown, but the capacitor 30 may also be connected to the third conductive path 73.

[0103] <Example 3>

[0104] The backup power supply control device 301 of the third embodiment is a structure in which a low-dropout regulator 32 (hereinafter also referred to as LDO32) is added to the backup power supply control device 1 of the first embodiment, and the other structures are the same. In addition, the backup power supply device 302 of the third embodiment is formed into a structure including the backup power supply control device 301 and the power storage unit 92, and the vehicle-mounted power supply system 300 of the third embodiment is formed into a structure including the backup power supply device 302 and the power supply unit 90. In addition, the same reference numerals are attached to the same structures as those of the first embodiment, and the description thereof is omitted.

[0105] LDO32 outputs a voltage that is reduced by reducing the input voltage to a specified voltage. Figure 7As shown, LDO 32 is interposed between the power storage unit 92 and the load 94. The end of the LDO 32 on the power storage unit 92 side is electrically connected to the fourth conductive path 74, and the LDO 32 is electrically connected to the power storage unit 92 via the fourth conductive path 74. The end of the LDO 32 on the load 94 side is electrically connected to the second conductive path 72 (power path 70), and the LDO 32 is electrically connected to the load 94 via the second conductive path 72 (power path 70). LDO 32 reduces the voltage applied to the fourth conductive path 74 to a voltage lower than the voltage of the second conductive path 72 when the power supply from the power supply unit 90 is in a normal state, and applies it to the second conductive path 72. Here, the voltage reduced by LDO 32 is set to a voltage greater than 0V and less than or equal to the first threshold voltage Vth1.

[0106] The operation of the backup power supply control device 301 provided with the LDO 32 will be described. Here, an example in which the discharge by the charge and discharge unit 10 is not performed when the failure state is reached will be described.

[0107] When the power supply from the power supply unit 90 is in a normal state, the voltage stepped down by the LDO 32 is lower than the voltage applied to the second conductive path 72 based on the output voltage of the power supply unit 90 . Therefore, the voltage stepped down by the LDO 32 is not applied to the second conductive path 72 .

[0108] After that, if the failure state is reached, power is not supplied from the power supply unit 90, the voltage of the second conductive path 72 decreases, and if it is lower than the voltage decreased by the LDO 32, the voltage decreased by the LDO 32 is output to the second conductive path 72. Thus, power is supplied from the LDO 32 to the load 94. After that, when the second discharge unit 12 discharges, the voltage of the second conductive path 72 exceeds the voltage decreased by the LDO 32, and the output of the LDO 32 stops.

[0109] Next, the effects of the backup power supply control device 301 of the third embodiment will be described.

[0110] The backup power supply control device 301 of the third embodiment includes an LDO 32 (low dropout regulator), one end of which is electrically connected to the power storage unit 92, and the other end of which is electrically connected to the second conductive path 72. When the power supply based on the power supply unit 90 becomes a failure state, the input voltage based on the charging voltage of the power storage unit 92 is stepped down and an output voltage is applied to the second conductive path 72. According to this structure, when the power supply is interrupted due to an open circuit fault or the like on the power supply unit 90 side, power can be immediately supplied to the load 94 (power supply target) through the LDO 32 (low dropout regulator). Therefore, the possibility of maintaining power supply to the load 94 (power supply target) is improved during the period from the interruption of power supply based on the power supply unit 90 to the start of the backup operation by the charging and discharging unit 10 (first discharge unit) or the second discharge unit 12. In addition, during the period when the voltage of the second conductive path 72 exceeds the predetermined voltage (the voltage that becomes the potential difference at which the voltage step-down operation is started by the low-dropout regulator), the voltage step-down operation by the LDO 32 (low-dropout regulator) is not performed, so during this period, the discharge of the power storage unit 92 by the LDO 32 (low-dropout regulator) can be suppressed. In addition, in the above structure, an example is shown in which the other end of the LDO 32 is connected to the second conductive path 72, but the other end of the LDO 32 may be connected to the third conductive path 73.

[0111] <Other embodiments>

[0112] The present invention is not limited to the embodiments illustrated in the above description and drawings, and for example, the following embodiments are also included in the technical scope of the present invention.

[0113] In the above-mentioned embodiment, the power supply unit 90 uses a lead storage battery, but the structure is not limited to this. In any example of this specification, other power supply units (power sources such as lithium ion batteries, AC generators, and converters) can be used for the power supply unit 90 instead of or in combination with the lead storage battery. The number of power supply units constituting the power supply unit 90 is not limited to one, and it can also be composed of multiple power supply units.

[0114] In the above-mentioned embodiment, the electric storage unit 92 uses an electric double layer capacitor (EDLC), but the present invention is not limited to this structure, and in any example of this specification, other electric storage units such as lithium ion capacitors, capacitors, lead storage batteries, lithium ion batteries, etc. may be used for the electric storage unit 92. In addition, the number of electric storage units constituting the electric storage unit 92 is not limited to one, and it may be composed of a plurality of electric storage units.

[0115] In the above-described embodiment, FET is illustrated as an example of the input cutoff unit 14 , but other electrical components such as semiconductor switches or relays may be used.

[0116] In the above embodiment, the input cutoff unit 14 switches between the permitted state and the prohibited state according to the instruction from the control unit 20, but the input cutoff unit 14 itself may determine whether to be in the permitted state or the prohibited state. For example, the input cutoff unit 14 may monitor the voltage of the first conductive path 71 and determine whether it is in the failed state, and switch between the permitted state and the prohibited state based on the determination result.

[0117] In the above-described embodiment, FET is illustrated as an example of the output cutoff unit 16 , but other electrical components such as semiconductor switches or relays may be used.

[0118] In the above-mentioned embodiment, the output cutoff section 16 switches between the permitted state and the prohibited state according to the instruction from the control section 20, but the output cutoff section 16 itself may determine whether to enter the permitted state or the prohibited state. For example, the output cutoff section 16 may monitor the voltage of the first conductive path 71 and the voltage of the third conductive path 73, and thus, when a failure state is detected, determine whether there is an abnormality that the discharge of the power storage section 92 by the charging and discharging section 10 cannot be performed, and switch between the permitted state and the prohibited state based on the determination result.

[0119] In the above embodiment, the charging and discharging unit 10 is illustrated as an example of the first discharging unit, but the charging circuit and the discharging circuit may be separately configured as long as the configuration can discharge the power storage unit 92. In addition, the first discharging unit is not limited to a voltage conversion circuit, and may be configured by a switch, for example.

[0120] In the above embodiment, the example in which the second discharge unit 12 is constituted by a switch is shown, but any configuration may be used as long as it can discharge the power storage unit 92, and may be constituted by a DCDC converter, for example.

[0121] In the above embodiment, the second threshold voltage Vth2 is the same as the first threshold voltage Vth1, but as long as it is a voltage greater than 0V, less than the output voltage of the power supply unit 90 and less than the output voltage of the storage unit 92, it can be greater than the first threshold voltage Vth1 or less than the first threshold voltage Vth1.

[0122] In the above embodiment, the time lag from detection of the failure state to output of the control signal by the second control unit 24 is shorter than that of the first control unit 22 , but the time lag may be the same or longer.

[0123] Description of symbols

[0124] 1. 201, 301… Vehicle-mounted backup power supply control device

[0125] 2. 202, 302… Vehicle-mounted backup power supply device

[0126] 10 ...Charging and discharging section (first discharging section)

[0127] 12…Second discharge section

[0128] 14…Input cut-off section

[0129] 16…Output cut-off section (switch section)

[0130] 22…First control unit

[0131] 24…Second control unit

[0132] 30…Capacitor

[0133] 32…Low Dropout Regulator

[0134] 61…First discharge path

[0135] 62…Second discharge path

[0136] 70…Power Path

[0137] 71 ... first conductive path

[0138] 72 ... second conductive path

[0139] 73…third conductive path

[0140] 90…Power supply

[0141] 92…Electricity storage unit

[0142] 94…Load (power supply object)

[0143] 100, 200, 300...In-vehicle power supply system

Claims

1. A vehicle-mounted backup power supply control device, in a vehicle-mounted power supply system including a power supply unit and a power storage unit as a vehicle-mounted storage battery, wherein power from the power supply unit is supplied to a power supply target via a power path, and controls the power supply from the power storage unit, wherein: The vehicle-mounted backup power supply control device comprises: a first discharge unit that performs a first discharge operation of supplying a discharge current based on the power supplied from the power storage unit to the power path via a first discharge path; a second discharge unit that performs a second discharge operation of supplying a discharge current based on the power supplied from the power storage unit toward the power supply destination via a second discharge path different from the first discharge path; a first control unit configured to cause the first discharge unit to perform the first discharge operation only when the power supply from the power supply unit fails; and a second control unit causing the second discharge unit to perform the second discharge operation when the power supply from the power supply unit becomes the failed state and when at least the first discharge performed by the first discharge unit is in an abnormal state; A switch section for switching between an on state and an off state is provided at a position closer to the power supply destination than a connection portion of the first discharge path in the power path, The switch section allows power supply from the power supply section to the power supply target side when in an on state, and cuts off power supply from the power supply section to the power supply target side when in an off state. The second discharge path is electrically connected to a portion of the power path that is closer to the power supply destination than the switch portion. When the power supply from the power supply unit becomes the failed state, the second control unit switches the switch unit to the OFF state when at least the first discharge power by the first discharge unit is the abnormal state.

2. The vehicle-mounted backup power supply control device according to claim 1, wherein: The first control unit and the second control unit operate independently of each other.

3. The vehicle-mounted backup power supply control device according to claim 1 or 2, wherein: A capacitor is provided, the capacitor being electrically connected to the power path and being charged based on the power supplied from the power supply unit.

4. The vehicle-mounted backup power supply control device according to claim 1 or 2, wherein: A low-dropout regulator is provided, one end of which is electrically connected to the power storage unit and the other end is electrically connected to the power path. When the power supply based on the power supply unit becomes the failed state, the input voltage based on the charging voltage of the power storage unit is stepped down and an output voltage is applied to the power path.

5. The vehicle-mounted backup power supply control device according to claim 1 or 2, wherein: When the power supply from the power supply unit enters the failure state, the second control unit causes the second discharge unit to start the second discharge operation before the first discharge unit starts the first discharge operation under the control of the first control unit.

6. The vehicle-mounted backup power supply control device according to claim 1 or 2, wherein: The first discharge unit is a voltage conversion unit that steps up or steps down an input voltage corresponding to a charge voltage of the power storage unit to apply a predetermined output voltage to the first discharge path. The second discharge unit is a switch that allows power to be supplied from the power storage unit to the power supply target when in an on state, and cuts off power to be supplied from the power storage unit to the power supply target when in an off state. The second control unit causes the second discharge unit to start the second discharge operation when power supply from the power supply unit enters the failure state, and stops the second discharge operation when the first discharge unit starts the first discharge operation during the second discharge operation.

7. A vehicle-mounted backup power supply device, comprising: The vehicle-mounted backup power supply control device according to any one of claims 1 to 6; and The power storage unit.

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