In-vehicle cutoff control device

Abstract

A vehicle-mounted cutoff control device (10) is provided with a conductive line (first conductive line (11)), a voltage generation unit (13), a short-circuit detection unit (14), and a drive unit (15). The conductive line (first conductive line (11)) is insulated from the low-voltage battery (3), and a voltage smaller than the output voltage of the high-voltage battery (5) is applied to the conductive line. A voltage generation unit (13) generates a voltage applied to a conductive line (first conductive line (11)) on the basis of an output voltage of a low-voltage battery (3) or a high-voltage battery (5). The short-circuit detection unit (14) is driven by receiving power from the conductive line (first conductive line (11)). The drive unit (15) operates by receiving power from the conductive line (first conductive line (11)), and outputs a cut-off signal for switching the cut-off unit (7) to a cut-off state. The short-circuit detection unit (14) receives a detection signal and detects a short circuit in the power line (6) on the basis of the detection signal. When the short-circuit detection unit (14) detects a short circuit in the power line (6), the drive unit (15) switches the cutoff unit (7) to the cutoff state.

Description

Technical Field

[0001] The present disclosure relates to a vehicle-mounted cutoff control device. Background Art

[0002] A driving circuit is disclosed in Patent Document 1. The driving circuit includes a power MOSFET and can turn off the power MOSFET.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 62-21322 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Among the power supply systems mounted on vehicles, there are power supply systems equipped with a low-voltage battery, a high-voltage battery, a power line that supplies power from the high-voltage battery, and a cut-off unit that can cut off the power line. For example, when a drive circuit such as that in Patent Document 1 is used to cause the cut-off unit to perform a cut-off action, a surge voltage may be generated near the cut-off unit during the cut-off action, and the voltage caused by the surge voltage may enter the low-voltage battery side. In addition, when a short circuit of the power line is detected based on the current value flowing in the power line and the drive circuit is activated, the voltage caused by the surge voltage may also enter the low-voltage battery side via the short-circuit detection unit that detects the short circuit and the drive circuit.

[0008] An object of the present disclosure is to provide a technology that can easily suppress a surge voltage generated by a cutoff operation of a cutoff unit from entering a low-voltage battery side.

[0009] Means for solving problems

[0010] As one of the present disclosures, a vehicle-mounted cut-off control device is used in a vehicle-mounted system, the vehicle-mounted system comprising: a low-voltage battery; a high-voltage battery, which is insulated from the low-voltage battery and has an output voltage greater than the output voltage of the low-voltage battery; a power line, which is supplied with power based on the high-voltage battery; a cut-off unit, which is provided on the power line and switches from a conducting state that allows current to flow through the power line to a cut-off state that cuts off the current flowing through the power line; and a current detection unit, which outputs a detection signal capable of determining the value of the current flowing through the power line. The vehicle-mounted cut-off control device comprises: a conductive line, which is insulated from the low-voltage battery and is supplied with a voltage greater than the voltage a voltage which is smaller than the output voltage of the high-voltage battery; a voltage generating unit which generates a voltage applied to the conductive path based on the output voltage of the low-voltage battery or the high-voltage battery; a short-circuit detecting unit which receives power from the conductive path and is driven; and a driving unit which receives power from the conductive path and operates and outputs a cutting signal for switching the cutting unit to the cutting state, the short-circuit detecting unit being input with the detection signal and detecting a short circuit of the power path based on the detection signal, and the driving unit switching the cutting unit to the cutting state when the short-circuit detecting unit detects a short circuit of the power path.

[0011] Effects of the Invention

[0012] The technology disclosed in the present invention can easily suppress the surge voltage generated by the cutting operation of the cutting unit from entering the low-voltage battery side. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a block diagram schematically illustrating an in-vehicle system including the in-vehicle cutoff control device according to the first embodiment.

[0014] Figure 2 This is a block diagram schematically illustrating an in-vehicle system including an in-vehicle cutoff control device according to a second embodiment.

[0015] Figure 3 This is a block diagram schematically illustrating an in-vehicle system including an in-vehicle cutoff control device according to a third embodiment. DETAILED DESCRIPTION

[0016] Hereinafter, embodiments of the present disclosure will be listed and illustrated.

[0017] [1] A vehicle-mounted cut-off control device, used in a vehicle-mounted system, the vehicle-mounted system comprising: a low-voltage battery; a high-voltage battery, insulated from the low-voltage battery, and having an output voltage greater than the output voltage of the low-voltage battery; a power line, to which power based on the high-voltage battery is supplied; a cut-off unit, provided in the power line, switching from a conductive state allowing current to flow through the power line to a cut-off state for cutting off the current flowing through the power line; and a current detection unit, outputting a detection signal capable of determining the value of the current flowing through the power line, the vehicle-mounted cut-off control device comprising: a conductive line, insulated from the low-voltage battery, to which a voltage greater than the output voltage of the low-voltage battery is applied a voltage smaller than the output voltage of the high-voltage battery; a voltage generating unit, which generates a voltage applied to the conductive line based on the output voltage of the low-voltage battery or the high-voltage battery; a short-circuit detecting unit, which receives power from the conductive line and is driven; and a driving unit, which receives power from the conductive line and operates, and outputs a cut-off signal for switching the cut-off unit to the cut-off state, the short-circuit detecting unit is input with the detection signal, and detects a short circuit of the power line based on the detection signal, and the driving unit switches the cut-off unit to the cut-off state when the short-circuit detecting unit detects a short circuit of the power line.

[0018] The vehicle-mounted cut-off control device described in [1] above is used in a vehicle-mounted system in which a low-voltage battery and a high-voltage battery are insulated from each other. The vehicle-mounted cut-off control device described above has a short-circuit detection unit that detects a short circuit in a power line to which power is supplied based on the high-voltage battery. Moreover, the vehicle-mounted cut-off control device described above has a drive unit that switches the cut-off unit to a cut-off state when the short-circuit detection unit detects a short circuit in the power line. The short-circuit detection unit and the drive unit are driven by power from a conductive line insulated from the low-voltage battery. Therefore, according to the vehicle-mounted cut-off control device described above, even if a surge voltage generated by the cut-off action of the cut-off unit enters the short-circuit detection unit and the drive unit, it is easily suppressed from entering the low-voltage battery side.

[0019] [2] According to the vehicle-mounted cutoff control device described in [1], the voltage generating unit has a transformer that insulates the low-voltage battery from the high-voltage battery and the conductive path, and boosts the voltage based on the low-voltage battery and applies it to the conductive path.

[0020] According to the above-mentioned vehicle-mounted cutoff current supply device [2], the insulation between the low-voltage battery and the high-voltage battery and the conductive path can be improved by the transformer. In addition, according to the above-mentioned vehicle-mounted cutoff control device, the voltage applied to the conductive path can be generated by the low-voltage battery.

[0021] [3] According to the vehicle-mounted cut-off control device described in [2], the transformer has a first winding portion and a second winding portion that are insulated from each other, and the voltage generating portion further has: a switching portion that switches between a permitted state in which current is allowed to flow from the low-voltage battery to the first winding portion and a released state in which the permitted state is released; and a control portion that controls the switching portion, the conductive line is electrically connected to the second winding portion, the cut-off portion has a current input portion, and the current input portion is insulated from the power line, the driving portion has: a capacitor that receives power from the conductive line; and a switch that is arranged between the conductive line and the current input portion, and the vehicle-mounted cut-off control device and the switching portion alternately repeat the switching between the permitted state and the released state, and accordingly, a charging current is supplied to the capacitor via the second winding portion and the conductive line, and the vehicle-mounted cut-off control device and the switch are turned on to discharge the capacitor and cause the driving current to flow to the current input portion.

[0022] The vehicle-mounted cut-off current supply device of the above-mentioned [3] is not only capable of inputting the current directly supplied from the second winding portion into the current input portion, but also capable of inputting the discharge current from the capacitor into the current input portion. Therefore, according to the above-mentioned vehicle-mounted cut-off control device, it is possible to take into account both the structure of suppressing the size of the transformer and the structure of being able to input a certain degree of current into the current input portion, and it is easy to miniaturize the structure that can improve the insulation between the low-voltage battery and the high-voltage battery and can drive the cut-off portion.

[0023] [4] In the vehicle-mounted cutoff control device according to [1], the voltage generating unit includes a voltage step-down unit that steps down a voltage based on the high-voltage battery and applies the stepped-down voltage to the conductive path.

[0024] According to the vehicle-mounted cutoff current supply device of the above-mentioned [4], the voltage to be applied to the conductive path can be generated by the high-voltage battery.

[0025] [5] According to any one of [1] to [4], the vehicle-mounted cut-off control device, the cut-off unit has a current input unit insulated from the power line, and is switched to the cut-off state in response to the driving current supplied from the driving unit flowing to the current input unit. After switching to the cut-off state, the cut-off state is maintained even if the supply of the driving current stops.

[0026] According to the above-mentioned vehicle-mounted cut-off current supply device [5], after the cut-off portion is switched to the cut-off state, even if the voltage caused by the surge voltage enters the driving portion and the driving portion cannot operate normally, and the supply of the driving current from the driving portion is stopped, the cut-off state of the cut-off portion can be maintained more reliably.

[0027] [6] In the vehicle-mounted cutoff control device according to [5], the cutoff unit is a pyrotechnic fuse, and the pyrotechnic fuse cuts off the power line when the drive current flows to the current input unit.

[0028] According to the above-mentioned vehicle-mounted cutoff current supply device [6], a driving current can be supplied to the current input unit to cause the pyrotechnic fuse to perform a cutoff operation. Such a pyrotechnic fuse is prone to generate a surge voltage near the pyrotechnic fuse as it cuts off, but the above-mentioned vehicle-mounted cutoff control device is unlikely to affect the low-voltage battery side due to the influence of such a surge voltage.

[0029] [7] According to any one of [1] to [6], the vehicle-mounted cut-off control device comprises: a voltage detection unit for detecting the voltage of the power line; and a determination unit for outputting an abnormal signal when the voltage detected by the voltage detection unit becomes a predetermined abnormal value, and the determination unit receives power from the conductive line to operate.

[0030] According to the vehicle-mounted cutoff current supply device of the above-mentioned [7], it is possible to realize a structure that outputs an abnormality signal when the voltage of the power line reaches an abnormal value by using the power supplied from the conductive line.

[0031] <First Embodiment>

[0032] 1-1. Overview of the in-vehicle system 1

[0033] Figure 1 The vehicle-mounted system 1 having the vehicle-mounted cutoff control device 10 of the first embodiment is shown. The vehicle-mounted system 1 is a system mounted on a vehicle and is a system capable of supplying power to various loads. The vehicle equipped with the vehicle-mounted system 1 is, for example, an electric vehicle, a plug-in hybrid vehicle, a hybrid vehicle, or other types of vehicles.

[0034] like Figure 1 As shown, the vehicle-mounted system 1 includes a low-voltage battery 3 , a low-voltage power line 4 , a high-voltage battery 5 , a power line 6 , a cutoff unit 7 , a current detection unit 8 , a vehicle-mounted cutoff control device 10 , and a starter switch 90 .

[0035] If the vehicle is a plug-in hybrid vehicle or a hybrid vehicle, the start switch 90 corresponds to, for example, an ignition switch for starting the engine. If the vehicle is an electric vehicle, the start switch 90 corresponds to a power switch for starting the EV system.

[0036] The low-voltage battery 3 is a vehicle-mounted storage battery, which can be composed of a secondary battery such as a lead-acid battery or a lithium-ion battery, or can be composed of other types of storage batteries. When the low-voltage battery 3 is fully charged, it applies a DC voltage to the low-voltage side power line 4. The output voltage of the low-voltage battery 3 when fully charged is greater than 0V, for example, 12V.

[0037] The low-voltage side power line 4 is an electrical line that transmits power based on the low-voltage battery 3. The purpose of the low-voltage side power line 4 is not limited. For example, it can be configured as an electrical line that supplies power to a power supply object (for example, an ECU (Electronic Control Unit), a low-voltage load, etc.) not shown in the figure. The low-voltage side power line 4 has a first low-voltage side power line 4A electrically connected to the positive electrode of the low-voltage battery 3 and a second low-voltage side power line 4B electrically connected to the negative electrode of the low-voltage battery 3. The output voltage of the low-voltage battery 3 is applied between the first low-voltage side power line 4A and the second low-voltage side power line 4B.

[0038] The high-voltage battery 5 is a vehicle-mounted storage battery, which may be composed of a secondary battery such as a lithium-ion battery, or may be composed of other types of storage batteries. The high-voltage battery 5 is insulated from the low-voltage battery 3. When the high-voltage battery 5 is fully charged, it applies a DC voltage to the power line 6. The output voltage of the high-voltage battery 5 when fully charged is greater than 0V, and is also greater than the output voltage of the low-voltage battery 3 when fully charged, for example, 400V.

[0039] The power line 6 is an electrical line that transmits power based on the high-voltage battery 5. The purpose of the power line 6 is not limited, for example, it can be configured as an electrical line that supplies power to a high-voltage load (such as an inverter) for vehicle use. The power line 6 has a first power line 6A and a second power line 6B. One end of the first power line 6A is electrically connected to the positive electrode of the high-voltage battery 5, and the other end is electrically connected to one side of the cut-off portion 7. One end of the second power line 6B is electrically connected to the negative electrode of the high-voltage battery 5, and the other end is electrically connected to the other side of the cut-off portion 7. The second power line 6B is electrically connected to the ground. The output voltage of the high-voltage battery 5 is applied between the first power line 6A and the second power line 6B. A voltage higher than the voltage applied to the low-voltage side power line 4 is applied to the power line 6. The first power line 6A and the second power line 6B are short-circuited to each other when the cut-off portion 7 is in the on state, and are insulated from each other when the cut-off portion 7 is in the cut-off state.

[0040] exist Figure 1In the example of , the cut-off section 7 is provided in the power line 6, and performs a cut-off operation of switching from a conduction state that allows current to flow through the power line 6 to a cut-off state that cuts off the current flow. The cut-off section 7 includes a current input section 71, conductor sections 72, 73, 74, an igniter 75, and a displacement section (not shown). The cut-off section 7 is, for example, a pyrotechnic fuse that cuts off the power line 6 when a driving current flows through the current input section 71. As the pyrotechnic fuse, a known pyrotechnic fuse (pyrofuse (registered trademark)) or other powder fuse can be preferably used.

[0041] The current input portion 71 has a first terminal portion 76 and a second terminal portion 77. The current input portion 71 is a portion through which current flows from the first terminal portion 76 toward the second terminal portion 77 when the drive portion 15 described later outputs a cutoff signal (more specifically, when the drive portion 15 described later supplies a drive current). The current input portion 71 is insulated from the power line 6.

[0042] Conductor 72 is a terminal connected to first power line 6A and short-circuited to first power line 6A. Conductor 73 is a terminal connected to second power line 6B and short-circuited to second power line 6B. Conductor 74 is a conductor that short-circuits conductors 72 and 73.

[0043] The igniter 75 is a part that functions to generate a small-scale explosion when current flows from the first terminal 76 to the second terminal 77, and to move the displacement part by the explosion. The displacement part functions in the following manner: before the explosion occurs in the igniter 75 (when the conductor parts 72, 73, 74 are short-circuited with each other), it is maintained at a predetermined position, and when the explosion occurs in the igniter 75, it is displaced to the conductor part 74 side by the explosion, and the conductor part 74 is cut off and cut off.

[0044] When the driving current supplied from the driving unit 15 described later flows to the current input unit 71 (specifically, when the driving current flows from the first terminal unit 76 to the second terminal unit 77 via the igniter 75), the cut-off unit 7 operates to cut off the power line 6. That is, the cut-off unit 7 switches from the on state to the cut-off state when the driving current flows to the current input unit 71. After switching to the cut-off state, the cut-off unit 7 maintains the cut-off state even if the supply of the driving current stops.

[0045] The current detection unit 8 is configured as, for example, a well-known current sensor. The current detection unit 8 detects the value of the current flowing through the power line 6, and outputs a detection signal that can identify the detected current value.

[0046] 1-2. Configuration of the vehicle-mounted cutoff control device 10

[0047] The vehicle-mounted cutoff control device 10 is a device used in the vehicle-mounted system 1. The vehicle-mounted cutoff control device 10 includes a first conductive path 11, a second conductive path 12, a voltage generating unit 13, a short-circuit detecting unit 14, a driving unit 15, and a resistor 16.

[0048] The voltage generating unit 13 generates a voltage to be applied to the first conductive path 11 based on the output voltage of the low voltage battery 3. The voltage generating unit 13 includes a transformer 20, a switching unit 21, and a control unit 22.

[0049] The transformer 20 insulates the low voltage battery 3 from the high voltage battery 5 and insulates the low voltage battery 3 from the first conductive path 11. The transformer 20 boosts the voltage based on the low voltage battery 3 and applies it to the first conductive path 11. The transformer 20 has a first winding portion 23 and a second winding portion 24. The first winding portion 23 and the second winding portion 24 are insulated from each other. The first winding portion 23 and the second winding portion 24 are both configured as coils. When the transformer 20 generates a current change in the first winding portion 23, the second winding portion 24 generates a voltage corresponding to the current change in the first winding portion 23.

[0050] The switching unit 21 is provided in the low-voltage side power line 4. The switching unit 21 is provided between the low-voltage battery 3 and the first winding unit 23. The switching unit 21 switches between a permitted state in which current is allowed to flow from the low-voltage battery 3 to the first winding unit 23 and a released state in which the permitted state is released. The switching unit 21 has a switching switch 21A. By turning the switching switch 21A into an on state, the switching unit 21 becomes a permitted state in which current is allowed to flow from the low-voltage battery 3 to the first winding unit 23. By turning the switching switch 21A into an off state, the switching unit 21 becomes a released state in which the permitted state is released. The switching switch 21A is composed of, for example, a switching element, and more specifically, a semiconductor switching element such as a FET (Field Effect Transistor). In addition, the switching switch 21A may also be a switching element other than a FET (for example, a bipolar transistor, etc.).

[0051] The control unit 22 includes a control device. The control device is an information processing device having a computing function and an information processing function, and includes, for example, a CPU, a storage unit, etc. The control unit 22 outputs an on signal for turning on the switch 21A and an off signal for turning off the switch 21A. One of the on signal and the off signal is, for example, a high level signal, and the other is, for example, a low level signal.

[0052] The switch 21A performs an on operation when an on signal is supplied from the control unit 22. Thus, the switch unit 21 switches to the permission state. The switch 21A performs an off operation when an off signal is supplied from the control unit 22. Thus, the switch unit 21 switches to the release state.

[0053] When the switching unit 21 is in the allowed state, an input voltage Vin equal to the output voltage of the low-voltage battery 3 is applied to both ends of the first winding unit 23. When the voltage at both ends of the second winding unit 24 is set to the output voltage Vout, Vin / Vout=N1 / N2. That is, according to the switching of the switching switch 21A from the released state to the allowed state, an output voltage of Vout=Vin×N2 / N1 is generated in the second winding unit 24. In this embodiment, the number of turns N1 of the first winding unit 23 is less than the number of turns N2 of the winding unit of the second winding unit 24. Therefore, a voltage after boosting the output voltage of the low-voltage battery 3 is generated in the second winding unit 24. The voltage generated in the second winding unit 24 is applied to the first conductive path 11.

[0054] In this way, the voltage generating unit 13 boosts the voltage of the low voltage battery 3 and applies the boosted voltage to the first conductive path 11 .

[0055] The first conductive path 11 is equivalent to an example of a "conductive path". The first conductive path 11 is insulated from the low-voltage battery 3. The first conductive path 11 is electrically connected to the second winding portion 24, and a voltage generated by the voltage generating portion 13 is applied to the first conductive path 11. A voltage lower than the output voltage of the high-voltage battery 5 is applied to the first conductive path 11. The first conductive path 11 is an electrical path provided between one end of the second winding portion 24 and the driving portion 15. The second conductive path 12 is an electrical path provided between the other end of the second winding portion 24 and the driving portion 15. The second conductive path 12 is electrically connected to the ground. The second conductive path 12 is electrically connected to the second power line 6B via the ground, and is short-circuited to the second power line 6B.

[0056] The short circuit detection unit 14 is provided between the first conductive line 11 and the second conductive line 12, and is connected to the first conductive line 11 and the second conductive line 12. The short circuit detection unit 14 is driven by receiving power from the first conductive line 11. The short circuit detection unit 14 is input with the detection signal output from the current detection unit 8. The short circuit detection unit 14 detects a short circuit of the power line 6 based on the detection signal. For example, the short circuit detection unit 14 determines whether the value of the current flowing through the power line 6 exceeds the threshold current based on the detection signal, and determines that the power line 6 is short-circuited when it is determined that it exceeds the threshold current. The short circuit detection unit 14 outputs a non-short circuit signal (off signal) at a stage before the short circuit of the power line 6 is detected, and outputs a short circuit signal (on signal) when the short circuit of the power line 6 is detected.

[0057] The driving unit 15 is provided between the first conductive line 11 and the second conductive line 12, and is connected to the first conductive line 11 and the second conductive line 12. The driving unit 15 receives power from the first conductive line 11 to operate, and outputs a cutoff signal for switching the cutoff unit 7 to a cutoff state. When the short-circuit detection unit 14 detects a short circuit of the power line 6, the driving unit 15 switches the cutoff unit 7 to a cutoff state. The driving unit 15 includes a capacitor 30 and a switch 31.

[0058] The capacitor 30 is an element electrically connected to the first conductive line 11 and the second conductive line 12 and receives power from the first conductive line 11. One electrode of the capacitor 30 is electrically connected to the first conductive line 11, and the other electrode is electrically connected to the second conductive line 12. The capacitor 30 receives power from the first conductive line 11 and is charged.

[0059] The switch 31 is provided between the first conductive line 11 and the current input unit 71. The switch 31 is composed of a semiconductor switch such as a FET (Field Effect Transistor), a mechanical relay, and the like. The switch 31 allows current to flow from the capacitor 30 side to the first terminal 76 side when it is in the on state, and cuts off current from the capacitor 30 side to the first terminal 76 side when it is in the off state. Specifically, the switch 31 becomes the on state when the short-circuit detection unit 14 outputs a short-circuit signal (on signal), and becomes the off state when the short-circuit detection unit 14 outputs a non-short-circuit signal (off signal). Furthermore, when the switch 31 is in the off state, the power supply through the switch 31 is bidirectionally cut off, and when the switch 31 is in the on state, the power supply through the switch 31 is bidirectionally allowed.

[0060] In this way, when a non-short-circuit signal is input from the short-circuit detection unit 14, the drive unit 15 turns the switch 31 into an off state, and cuts off the current flowing from the capacitor 30 side to the first terminal portion 76 side. In addition, when a short-circuit signal is input from the short-circuit detection unit 14, the drive unit 15 outputs a cut-off signal for switching the cut-off unit 7 to a cut-off state. Specifically, when a short-circuit signal is input from the short-circuit detection unit 14, the drive unit 15 switches the switch 31 to an on state. The capacitor 30 is discharged according to the operation of the switch 31, and the drive current flows to the current input unit 71. That is, when the short-circuit detection unit 14 detects a short circuit in the power line 6, the drive unit 15 supplies a drive current to the current input unit 71, and switches the cut-off unit 7 to a cut-off state.

[0061] The resistor 16 has a function of discharging the capacitor 30 . The resistor 16 is connected in parallel with the capacitor 30 between the first conductive path 11 and the second conductive path 12 , and is connected in parallel with the disconnection portion 7 .

[0062] 1-3. Operation of the vehicle-mounted cutoff control device 10

[0063] The voltage generating unit 13 performs a generating operation to generate a voltage to be applied to the first conductive path 11 based on the output voltage of the low-voltage battery 3. During the generating operation, the control unit 22 provides an on / off signal that alternately repeats an on signal and an off signal to the switching switch 21A, so that the switching switch 21A is turned on and off. According to the switching of the switching switch 21A from the off state to the on state, an input voltage Vin equivalent to the output voltage of the low-voltage battery 3 is applied to both ends of the first winding unit 23, and according to the switching of the switching switch 21A from the on state to the off state, the voltage from the low-voltage battery 3 is released from the both ends of the first winding unit 23. Through such an on / off operation, the state of applying the output voltage V1 to both ends of the first winding unit 23 and the state of releasing the application of the output voltage V1 to both ends of the first winding unit 23 are alternately switched. According to such an on / off operation, an output voltage of about V1×N2 / N1 at maximum is generated in the second winding unit 24. In this way, the switching between the permission state and the release state is repeated alternately by the switching unit 21, and power is supplied from the second winding unit 24 to the first conductive path 11, and power is supplied to the short-circuit detection unit 14 and the driving unit 15 via the first conductive path 11. That is, charging current is supplied to the capacitor 30. In this state, a certain amount of current can flow through the resistor 16.

[0064] The voltage generating unit 13 may also start the above-mentioned generating action according to the start switch 90 for starting the vehicle being switched from the off state to the on state. Moreover, when the start switch 90 is in the on state, the above-mentioned generating action may be continued until it becomes the off state. Moreover, the voltage generating unit 13 may also stop the above-mentioned generating action when the start switch 90 is switched from the on state to the off state. In this example, when the start switch 90 is switched from the on state to the off state and maintained in the off state, the switching unit 21 maintains the above-mentioned release state, so if the switch 31 is in the off state, the power supply from the capacitor 30 to the current input unit 71 is cut off, and the capacitor 30 is discharged through the resistor unit 16. On the other hand, when the start switch 90 is switched from the off state to the on state and maintained in the on state, the voltage generating unit 13 performs the above-mentioned generating action, so if the switch 31 is in the off state, the charging current is supplied to the capacitor 30 from the second winding unit 24 side, and the current flows to the resistor unit 16.

[0065] The short-circuit detection unit 14 detects a short circuit of the power line 6 based on a detection signal that can determine the value of the current flowing through the power line 6. When the short-circuit detection unit 14 detects a short circuit of the power line 6, it outputs a short-circuit signal. When the short-circuit signal is input, the drive unit 15 switches the switch 31 to the on state. When the switch 31 is switched from the off state to the on state while the capacitor 30 is being charged, the capacitor 30 is discharged according to the on action of the switch 31, and the drive current flows to the current input unit 71. When the drive current is supplied from the capacitor 30 to the current input unit 71, a small-scale explosion occurs in the igniter 75, and the cut-off unit 7 cuts off the power line 6. After the cut-off unit 7 is switched to the cut-off state, the cut-off state is maintained even if the supply of the drive current stops.

[0066] In this embodiment, the maximum value of the driving current supplied to the current input unit 71 in response to the on-operation of the switch 31 is preferably greater than the maximum value of the charging current supplied to the capacitor 30 when the capacitor 30 is charged. The control unit 22 adjusts the duty ratio to achieve such a relationship and supplies a PWM signal to the switching switch 21A.

[0067] 1-4. Examples of effects

[0068] The vehicle-mounted cut-off control device 10 is used in a vehicle-mounted system 1 having a structure in which a low-voltage battery 3 and a high-voltage battery 5 are insulated from each other. The vehicle-mounted cut-off control device 10 has a short-circuit detection unit 14 that detects a short circuit of a power line 6 to which power based on the high-voltage battery 5 is supplied. In addition, the vehicle-mounted cut-off control device 10 has a drive unit 15 that switches the cut-off unit 7 to a cut-off state when the short-circuit detection unit 14 detects a short circuit of the power line 6. The short-circuit detection unit 14 and the drive unit 15 are driven by receiving power from a first conductive line 11 insulated from the low-voltage battery 3. Therefore, according to the vehicle-mounted cut-off control device 10, even if a surge voltage generated by the cut-off action of the cut-off unit 7 enters the short-circuit detection unit 14 and the drive unit 15, it is easy to suppress the surge voltage from entering the low-voltage battery 3 side.

[0069] Furthermore, the voltage generating unit 13 includes a transformer 20, which insulates the low voltage battery 3 from the high voltage battery 5 and the first conductive path 11, and boosts the voltage based on the low voltage battery 3 and applies it to the first conductive path 11. According to this structure, the insulation between the low voltage battery 3 and the high voltage battery 5 and the first conductive path 11 can be improved by the transformer 20. Furthermore, according to this structure, the voltage applied to the first conductive path 11 can be generated by the low voltage battery 3.

[0070] Furthermore, the vehicle-mounted cutoff control device 10 can input the discharge current from the capacitor 30 to the current input unit 71 instead of only inputting the current directly supplied from the second winding unit 24. Therefore, according to the vehicle-mounted cutoff control device 10, it is possible to achieve both a structure that suppresses the size of the transformer 20 and a structure that can input a certain amount of current to the current input unit 71, and it is easy to miniaturize the structure that can drive the cutoff unit 7 while improving the insulation between the low-voltage battery 3 and the high-voltage battery 5.

[0071] Furthermore, the cut-off portion 7 is switched to the cut-off state according to the flow of the driving current supplied from the driving portion 15 to the current input portion 71, and the cut-off state is maintained even if the supply of the driving current is stopped after switching to the cut-off state. According to this structure, after the cut-off portion 7 is switched to the cut-off state, even if the voltage caused by the surge voltage enters the driving portion 15 and the driving portion 15 does not operate normally, the supply of the driving current from the driving portion 15 is stopped, and the cut-off state of the cut-off portion 7 can be maintained more reliably.

[0072] Furthermore, the cut-off unit 7 is a pyrotechnic fuse that cuts off the power line 6 when the driving current flows to the current input unit 71. According to this structure, the driving current can be supplied to the current input unit 71 to make the pyrotechnic fuse perform a cut-off operation. Such a pyrotechnic fuse is prone to generate a surge voltage near the pyrotechnic fuse as the cut-off operation occurs, but the vehicle-mounted cut-off control device 10 is unlikely to affect the influence of such a surge voltage to the low-voltage battery 3 side.

[0073] <Second Embodiment>

[0074] In the first embodiment, the voltage generating unit is a structure that boosts the voltage based on the low voltage battery 3 and applies it to the first conductive path 11, but is not limited to this structure. In the second embodiment, an example of a structure in which the voltage generating unit steps down the voltage based on the high voltage battery 5 and applies it to the first conductive path 11 is described. In addition, in the description of the second embodiment, the same reference numerals are attached to the same structures as those in the first embodiment, and detailed descriptions are omitted.

[0075] 2-1. Structure of the vehicle-mounted system 201

[0076] Figure 2 The vehicle-mounted system 201 having the vehicle-mounted cutoff control device 210 of the second embodiment is shown. The vehicle-mounted system 201 is a system mounted on a vehicle and is a system capable of supplying power to various loads. The vehicle equipped with the vehicle-mounted system 201 is, for example, an electric vehicle, a plug-in hybrid vehicle, a hybrid vehicle, or other types of vehicles.

[0077] like Figure 2As shown, the vehicle-mounted system 201 includes a low-voltage battery 3, a low-voltage side power line 4, a high-voltage battery 5, a power line 6, a cutoff unit 7, a current detection unit 8, a vehicle-mounted cutoff control device 210, a starter switch 90, and a power supply target 91.

[0078] The power supply object 91 is, for example, an ECU (Electronic Control Unit), a low-voltage load, etc. The power supply object 91 is provided between the first low-voltage side power line 4A and the second low-voltage side power line 4B. The power supply object 91 is supplied with power from the low-voltage battery 3 via the low-voltage side power line 4.

[0079] The vehicle-mounted cutoff control device 210 is a device used in the vehicle-mounted system 201. The vehicle-mounted cutoff control device 210 includes a first conductive path 11, a second conductive path 12, a voltage step-down unit 213, a short-circuit detection unit 14, a drive unit 15, and a resistor unit 16.

[0080] The step-down unit 213 is equivalent to an example of a "voltage generating unit". The step-down unit 213 is configured as a step-down regulator, for example. The step-down unit 213 performs a generating operation of stepping down the voltage based on the high-voltage battery 5 and applying it to the first conductive path 11. The step-down unit 213 is connected to the first power line 6A, the second power line 6B, the first conductive path 11, and the second conductive path 12. The step-down unit 213 steps down the voltage between the first power line 6A and the second power line 6B, and applies it between the first conductive path 11 and the second conductive path 12.

[0081] 2-2. Operation of the vehicle-mounted cutoff control device 210

[0082] The step-down unit 213 performs the above-mentioned generating action. The step-down unit 213 may also start the above-mentioned generating action according to the start switch 90 for starting the vehicle being switched from the off state to the on state. Moreover, when the start switch 90 is in the on state, the above-mentioned generating action may be continued until it becomes the off state. Moreover, the step-down unit 213 may also stop the above-mentioned generating action when the start switch 90 is switched from the on state to the off state. In this example, when the start switch 90 is switched from the on state to the off state and maintained in the off state, if the switch 31 is in the off state, the energization from the capacitor 30 to the current input unit 71 is cut off, and the capacitor 30 is discharged through the resistor unit 16. On the other hand, when the start switch 90 is switched from the off state to the on state and maintained in the on state, the step-down unit 213 performs the above-mentioned generating action, so if the switch 31 is in the off state, the charging current is supplied to the capacitor 30 from the second winding unit 24 side, and the current flows to the resistor unit 16.

[0083] The short-circuit detection unit 14 detects a short circuit of the power line 6 based on a detection signal that can determine the value of the current flowing through the power line 6. When the short-circuit detection unit 14 detects a short circuit of the power line 6, it outputs a short-circuit signal. When the short-circuit signal is input, the drive unit 15 switches the switch 31 to the on state. When the switch 31 is switched from the off state to the on state while the capacitor 30 is being charged, the capacitor 30 is discharged according to the on action of the switch 31, and the drive current flows to the current input unit 71. When the drive current is supplied from the capacitor 30 to the current input unit 71, a small-scale explosion occurs in the igniter 75, and the cut-off unit 7 cuts off the power line 6. After the cut-off unit 7 is switched to the cut-off state, the cut-off state is maintained even if the supply of the drive current stops.

[0084] 2-3. Examples of effects

[0085] According to the vehicle-mounted cutoff control device 210, the voltage applied to the first conductive path 11 can be generated by the high-voltage battery 5. In addition, according to the vehicle-mounted cutoff control device 210, the low-voltage battery 3 side and the high-voltage battery 5 side can be configured as different circuits, so that the low-voltage battery 3 side and the high-voltage battery 5 side can be insulated without providing a component for insulation.

[0086] <Third Embodiment>

[0087] In the first embodiment or the second embodiment, a structure for monitoring whether the voltage of the high-voltage battery 5 becomes an abnormal value by using the power supplied from the first conductive path 11 may be added. In the third embodiment, an example of a structure for monitoring whether the voltage of the high-voltage battery 5 becomes an abnormal value by using the power supplied from the first conductive path 11 is added based on the structure of the first embodiment. In addition, in the description of the third embodiment, the same reference numerals are attached to the same structures as the first embodiment, and detailed descriptions are omitted.

[0088] 3-1. Structure of the vehicle-mounted system 301

[0089] Figure 3 The vehicle-mounted system 301 having the vehicle-mounted cutoff control device 310 of the third embodiment is shown. The vehicle-mounted system 301 is a system mounted on a vehicle and is a system capable of supplying power to various loads. The vehicle equipped with the vehicle-mounted system 301 is, for example, an electric vehicle, a plug-in hybrid vehicle, a hybrid vehicle, or other types of vehicles.

[0090] like Figure 3 As shown, the vehicle-mounted system 301 includes a low-voltage battery 3 , a low-voltage power line 4 , a high-voltage battery 5 , a power line 6 , a cutoff unit 7 , a current detection unit 8 , a vehicle-mounted cutoff control device 310 , and a starter switch 90 .

[0091] The vehicle-mounted cutoff control device 310 is used in the vehicle-mounted system 301 and includes a first conductive path 11 , a second conductive path 12 , a voltage generator 13 , a short-circuit detector 14 , a driver 15 , a resistor 16 , a voltage detector 40 , and a determination unit 50 .

[0092] The voltage detection unit 40 detects the voltage of the power line 6 (more specifically, the voltage between the first power line 6A and the second power line 6B). The voltage detection unit 40 is configured, for example, as a well-known voltage detection circuit (more specifically, a voltage divider circuit). The voltage detection unit 40 has a first voltage divider resistor 41 and a second voltage divider resistor 42. One end of the first voltage divider resistor 41 is electrically connected to the power line 6 (specifically, the first power line 6A). The other end of the first voltage divider resistor 41 is connected to one end of the second voltage divider resistor 42. The other end of the second voltage divider resistor 42 is connected to the second conductive line 12. The voltage detection unit 40 outputs a voltage signal that can determine the voltage of the power line 6. Specifically, the voltage detection unit 40 outputs a voltage obtained by dividing the voltage of the power line 6 using the first voltage divider resistor 41 and the second voltage divider resistor 42.

[0093] The determination unit 50 outputs an abnormal signal when the voltage detected by the voltage detection unit 40 becomes a predetermined abnormal value. The abnormal value may be a fixed value or a value set according to the SOC of the high-voltage battery 5 or the like. The determination unit 50 is electrically connected to the first conductive line 11 and the second conductive line 12, and operates by receiving power from the first conductive line 11. The determination unit 50 is configured as a comparator, for example. A voltage signal capable of determining the voltage of the power line 6 is input to the determination unit 50. The determination unit 50 determines whether the voltage of the power line 6 is an abnormal value based on the voltage signal. The determination unit 50 outputs an abnormal signal when it is determined that the voltage of the power line 6 is an abnormal value. Thus, the vehicle-mounted cutoff control device 310 can report to a device external to the vehicle-mounted cutoff control device 310 that the voltage of the power line 6 is abnormal.

[0094] 3-2. Examples of effects

[0095] According to the vehicle-mounted cutoff control device 310 , it is possible to realize a configuration in which an abnormality signal is output when the voltage of the power line 6 reaches an abnormal value, using the power supplied from the first conductive line 11 .

[0096] <Other Implementation Methods>

[0097] The present disclosure is not limited to the embodiments described in the above description and the accompanying drawings. For example, the features of the above or later embodiments can be combined in all combinations within the scope of non-contradiction. In addition, any feature of the above or later embodiments can be omitted as long as it is not explicitly stated as a necessary feature. In addition, the above embodiments can also be changed as follows.

[0098] In the above-mentioned embodiments, the cutoff unit and the current detection unit are not included in the vehicle-mounted cutoff control device. However, the cutoff unit and the current detection unit may be partially or entirely included in the vehicle-mounted cutoff control device.

[0099] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope of the claims or within the scope equivalent to the claims.

[0100] Description of Reference Numerals

[0101] 1: In-vehicle system

[0102] 3: Low voltage battery

[0103] 4: Low voltage side power line

[0104] 4A: First low-voltage side power line

[0105] 4B: Second low voltage side power line

[0106] 5: High voltage battery

[0107] 6: Power lines

[0108] 6A: First Power Line

[0109] 6B: Second power line

[0110] 7: Cutting part

[0111] 8: Current detection unit

[0112] 10: Vehicle-mounted cut-off control device

[0113] 11: First conductive circuit (conductive circuit)

[0114] 12: Second conductive circuit

[0115] 13: Voltage generation unit

[0116] 14: Short circuit detection unit

[0117] 15: Driving unit

[0118] 16: Resistor

[0119] 20: Transformer

[0120] 21: Switching Department

[0121] 21A: Toggle switch

[0122] 22: Control Department

[0123] 23: First winding section

[0124] 24: Second winding section

[0125] 30: Capacitor

[0126] 31: Switch

[0127] 40: Voltage detection unit

[0128] 41: The first voltage divider resistor

[0129] 42: Second voltage divider resistor

[0130] 50: Judgment Department

[0131] 71: Current input unit

[0132] 72: Conductor

[0133] 73: Conductor

[0134] 74: Conductor

[0135] 75: Ignition

[0136] 76: First terminal

[0137] 77: Second terminal portion

[0138] 90: Start switch

[0139] 91: Electricity supply recipients

[0140] 201: In-vehicle systems

[0141] 210: Vehicle-mounted cut-off control device

[0142] 213: Step-down unit

[0143] 301: In-vehicle systems

[0144] 310: Vehicle-mounted cut-off control device

Claims

1. A vehicle-mounted cutoff control device, used in a vehicle-mounted system, the vehicle-mounted system comprising: a low-voltage battery; a high-voltage battery insulated from the low-voltage battery and having an output voltage greater than the output voltage of the low-voltage battery; and a power line supplied with power based on the high-voltage battery; a cut-off unit provided in the power line and switching from a conduction state allowing current to flow through the power line to a cut-off state cutting off the current flowing through the power line; and a current detection unit that outputs a detection signal capable of determining a value of a current flowing through the power line, wherein The vehicle-mounted cutoff control device comprises: A conductive circuit, insulated from the low-voltage battery, to which a voltage smaller than an output voltage of the high-voltage battery is applied; a voltage generating unit, which generates a voltage applied to the conductive line based on an output voltage of the low-voltage battery or the high-voltage battery; a short circuit detection unit driven by receiving power from the conductive line; and a driving unit that receives power from the conductive line to operate and outputs a cutoff signal for switching the cutoff unit to the cutoff state; The short-circuit detection unit receives the detection signal and detects a short circuit of the power line based on the detection signal. The driving unit switches the cutoff unit to the cutoff state when the short-circuit detecting unit detects a short circuit of the power line.

2. The vehicle-mounted cutoff control device according to claim 1, wherein: The voltage generating unit includes a transformer that insulates the low voltage battery from the high voltage battery and the conductive path, and boosts a voltage generated by the low voltage battery and applies the boosted voltage to the conductive path.

3. The vehicle-mounted cutoff control device according to claim 2, wherein: The transformer has a first winding portion and a second winding portion insulated from each other. The voltage generating unit further includes: a switching unit that switches between a permitted state in which current is allowed to flow from the low voltage battery to the first winding unit and a released state in which the permitted state is released; and a control unit that controls the switching unit. The conductive circuit is electrically connected to the second winding portion, The cut-off section has a current input section, and the current input section is insulated from the power line. The driving unit includes: a capacitor receiving power from the conductive line; and a switch provided between the conductive line and the current input unit. The vehicle-mounted cutoff control device supplies a charging current to the capacitor via the second winding portion and the conductive path in response to the switching unit alternately repeating the switching between the permission state and the release state. The vehicle-mounted cutoff control device discharges the capacitor in response to the switch being turned on, thereby causing a drive current to flow to the current input unit.

4. The vehicle-mounted cutoff control device according to claim 1, wherein: The voltage generating unit includes a voltage step-down unit configured to step down a voltage of the high voltage battery and apply the stepped-down voltage to the conductive line.

5. The vehicle-mounted cutoff control device according to claim 1 or 2, wherein: The cut-off portion has a current input portion insulated from the power line, and is switched to the cut-off state in response to a driving current supplied from the driving portion flowing to the current input portion. After switching to the cut-off state, the cut-off state is maintained even if the supply of the driving current stops.

6. The vehicle-mounted cutoff control device according to claim 5, wherein: The cutoff section is a pyrotechnic fuse that cuts off the power line when the drive current flows to the current input section.

7. The vehicle-mounted cutoff control device according to claim 1 or 2, wherein: The vehicle-mounted cutoff control device comprises: a voltage detection unit, detecting the voltage of the power line; and a determination unit that outputs an abnormality signal when the voltage detected by the voltage detection unit reaches a predetermined abnormal value, The determination unit operates by receiving power from the conductive line.

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