In-vehicle cut-off current supply device

Abstract

A vehicle-mounted cut-off current supply device (10) is provided with a voltage conversion unit (11), a drive unit (14), and a control unit (17). The voltage conversion unit (11) converts a voltage input from the power supply unit (2) side and applies an output voltage between the first conductive path (81) and the second conductive path (82). The drive unit (14) causes the current supplied from the first conductive path (81) to flow toward the current input unit (7) when the cutoff condition is satisfied. The control unit (17) executes feedback control for controlling the voltage conversion unit (11) so that the output voltage becomes a target voltage. The control unit (17) starts feedback control when the cut-off condition is not satisfied, and increases the output voltage of the voltage conversion unit (11) when the cut-off condition is satisfied.

Description

Technical Field

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

[0002] Patent Document 1 discloses an airbag ignition circuit. This circuit includes a sensing MOS connected between a power source and an initiator, which turns on in response to an ignition signal. When the sensing MOS turns on, an ignition current flows to the initiator, igniting / exploding it and deploying the airbag with this momentum.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Laid-Open No. 2005-88748 Summary of the Invention

[0004] Problems to be solved by the invention

[0005] The technology of Patent Document 1 can be applied to configurations that use circuit breakers such as pyrotechnic fuses (registered trademark) to interrupt power lines. For the circuit breaker to interrupt power, the integrated value of the current supplied to the circuit breaker must reach a certain level. However, immediately after the sense MOS is switched on, the output voltage drops, reducing the current supplied to the circuit breaker and potentially delaying the circuit breaker's interruption action.

[0006] An object of the present invention is to provide a technology for easily and quickly performing a circuit breaker disconnection operation.

[0007] Means for solving problems

[0008] The vehicle-mounted current cut-off supply device disclosed in the present invention is used in a vehicle-mounted system, which includes a power supply unit and a circuit breaker, and the circuit breaker performs a cutting-off action of cutting off the power path corresponding to the current flowing to the current input unit. The vehicle-mounted current cut-off supply device causes the current supplied from the power supply unit to flow to the current input unit side when the cutting condition is met, wherein the vehicle-mounted current cut-off supply device includes: a voltage conversion unit, which converts the voltage input from the power supply unit side and applies an output voltage between the first conductive path and the second conductive path; a driving unit, which causes the current supplied from the first conductive path to flow to the current input unit side when the cutting condition is met; and a control unit, which performs feedback control, and the feedback control controls the voltage conversion unit in such a way that the output voltage becomes a target voltage. The control unit starts the feedback control in a state where the cutting condition is not met, and causes the output voltage of the voltage conversion unit to increase when the cutting condition is met.

[0009] Effects of the Invention

[0010] The technology according to the present invention facilitates rapid disconnection of a circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a circuit diagram schematically showing an in-vehicle system including the in-vehicle cutoff current supply device according to the first embodiment. Figure 2 This is a circuit diagram schematically showing an in-vehicle system including an in-vehicle current cutoff supply device according to a second embodiment. Figure 3 This is a circuit diagram schematically showing an in-vehicle system including an in-vehicle current cutoff supply device according to a third embodiment. DETAILED DESCRIPTION

[0012] [Description of Embodiments of the Present Disclosure]

[0013] Hereinafter, embodiments of the present disclosure are listed and exemplified.

[0014] [1] A vehicle-mounted current cut-off supply device is used in a vehicle-mounted system, the vehicle-mounted system comprising a power supply unit and a circuit breaker, the circuit breaker performing a cut-off operation to cut off the power path in response to the current flowing to the current input unit, the vehicle-mounted current cut-off supply device causing the current supplied from the power supply unit to flow to the current input unit side when a cut-off condition is satisfied, wherein the vehicle-mounted current cut-off supply device comprises: a voltage conversion unit that converts the voltage input from the power supply unit side and applies an output voltage between a first conductive path and a second conductive path; a drive unit that causes the current supplied from the first conductive path to flow to the current input unit side when the cut-off condition is satisfied; and a control unit that performs feedback control, the feedback control controlling the voltage conversion unit in such a manner that the output voltage becomes a target voltage, the control unit starting the feedback control in a state where the cut-off condition is not satisfied, and causing the output voltage of the voltage conversion unit to increase when the cut-off condition is satisfied.

[0015] The vehicle-mounted cutoff current supply device performs feedback control by the control unit starting before the cutoff condition is met, causing current to flow from the first conductive path to the current input portion of the circuit breaker when the cutoff condition is met. Therefore, when the cutoff condition is met, the vehicle-mounted cutoff current supply device can immediately direct the current supplied from the voltage conversion portion to the current input portion of the circuit breaker. Furthermore, the control unit increases the output voltage when the cutoff condition is met. Therefore, the vehicle-mounted cutoff current supply device can suppress a decrease in the output voltage of the voltage conversion portion, which would otherwise cause a decrease in the current flowing to the current input portion, when the cutoff condition is met. As a result, the circuit breaker's cutoff operation is swiftly performed.

[0016] Furthermore, if the target voltage is set higher to increase the output voltage before the cutoff condition is met, components such as the driver unit will need to use components with higher withstand voltages, leading to concerns about increased costs. In contrast, the aforementioned in-vehicle cutoff current supply device increases the output voltage of the voltage conversion unit after the cutoff condition is met, thus minimizing the risk of such cost increases.

[0017] According to the vehicle-mounted cut-off current supply device described in [1], the voltage conversion unit has a switching element, the switching element performs on-off operations corresponding to the control signal provided, the larger the duty ratio of the control signal provided to the switching element, the larger the output voltage, the vehicle-mounted cut-off current supply device also has a voltage detection circuit, the voltage detection circuit detects the voltage between the first conductive circuit and the second conductive circuit, the voltage detection circuit includes: a first resistor unit, one end of which is electrically connected to the first conductive circuit; a second resistor unit, one end of which is electrically connected to the other end of the first resistor unit, and the other end of which is electrically connected to the second conductive circuit. ; and an output line, electrically connected to the connecting portion of the other end of the first resistor unit and one end of the second resistor unit, the control unit is input with the voltage of the output line, and the smaller the output voltage determined according to the voltage of the output line is relative to the target voltage, the larger the duty cycle is set, and the control signal of the set duty cycle is provided to the switching element, the vehicle-mounted cut-off current supply device further includes a parallel switch, the parallel switch is arranged in parallel with the second resistor unit, and when the cut-off condition is met, the parallel switch is switched to the on state, and the current flows from the first conductive path side to the second conductive path side via the parallel switch.

[0018] When the cutoff condition is met, the parallel switch in the vehicle-mounted cutoff current supply device switches to the on-state, allowing current to flow from the first conductive path to the second conductive path via the parallel switch. Therefore, when the cutoff condition is met, the control unit reduces the voltage input from the output line, increasing the set duty cycle. This causes the output voltage of the voltage conversion unit to increase. In other words, the vehicle-mounted cutoff current supply device can control the control unit to increase the output voltage of the voltage conversion unit when the cutoff condition is met, without incorporating into the control unit any structure for determining whether the cutoff condition has been met or any structure for performing processing corresponding to the cutoff condition being met.

[0019] [3] The vehicle-mounted cutoff current supply device according to [2], wherein when the cutoff condition is satisfied, the parallel switch is switched to an on state, and the output line and the second conductive path are short-circuited.

[0020] When the cutoff condition is met, the vehicle-mounted cutoff current supply device short-circuits the output line and the second conductive path. Therefore, when the cutoff condition is met, the control unit rapidly reduces the voltage input from the output line, causing the set duty cycle to rapidly increase. This causes the output voltage of the voltage conversion unit to rapidly increase. In other words, the vehicle-mounted cutoff current supply device can control the control unit to rapidly increase the output voltage of the voltage conversion unit when the cutoff condition is met, without incorporating into the control unit any structure for determining whether the cutoff condition has been met or any structure for performing processing corresponding to the cutoff condition being met.

[0021] [4] A vehicle-mounted cut-off current supply device according to [2] or [3], wherein the vehicle-mounted cut-off current supply device includes a signal generating unit, the signal generating unit outputs an indication signal when the cut-off condition is met, the indication signal output from the signal generating unit is provided to the driving unit and the parallel switch, the driving unit supplies the current supplied from the first conductive circuit to the current input unit side when the indication signal is provided, and the parallel switch is switched to the on state when the indication signal is provided.

[0022] If the driver and parallel switch operate based on the results of the cutoff condition determination by different determination units, there are cases where the parallel switch does not operate even if the driver operates, or the timing of the operations of the driver and parallel switch are misaligned. In contrast, the driver and parallel switch of the vehicle-mounted cutoff current supply device both operate in response to the instruction signal from the signal generator. Therefore, when the vehicle-mounted cutoff current supply device causes current to flow from the driver to the current input unit in response to the establishment of the cutoff condition, it can more reliably increase the output voltage of the voltage conversion unit.

[0023] [5] The vehicle-mounted cut-off current supply device according to [1], wherein the voltage conversion unit has a switching element, and the switching element performs on-off actions corresponding to the control signal provided, and the output voltage increases as the duty cycle of the control signal provided to the switching element increases. The control unit is a structure that outputs the control signal to control the voltage conversion unit, and when the cut-off condition is met, the output voltage of the voltage conversion unit increases by increasing the duty cycle of the output control signal.

[0024] The vehicle-mounted cutoff current supply device can increase the output voltage of the voltage converter by increasing the duty cycle of the control signal output from the control unit when the cutoff condition is met. Therefore, the vehicle-mounted cutoff current supply device can easily simplify the structure for increasing the output voltage from the voltage converter.

[0025] Furthermore, the vehicle-mounted cutoff current supply device may stop feedback control when increasing the duty cycle of the control signal output from the control unit, or may increase the duty cycle while continuing feedback control. The duty cycle may be increased, for example, by setting a predetermined increase duty cycle. As another example, the duty cycle may be increased by adding a predetermined addition duty cycle to the duty cycle determined by the predetermined calculation when the cutoff condition is not satisfied, in a configuration in which the control unit determines the duty cycle by a predetermined calculation.

[0026] [6] In the vehicle-mounted cutoff current supply device according to [1], the control unit increases the target voltage when the cutoff condition is satisfied, thereby increasing the output voltage of the voltage conversion unit.

[0027] The vehicle-mounted cutoff current supply device can increase the output voltage of the voltage converter by increasing the target voltage when the cutoff condition is met. Therefore, the vehicle-mounted cutoff current supply device can easily simplify the structure for increasing the output voltage of the voltage converter.

[0028] [7] The vehicle-mounted cutoff current supply device according to any one of [1] to [6], wherein the vehicle-mounted cutoff current supply device includes a capacitor, one end of the capacitor is electrically connected to the first conductive path and the other end is electrically connected to the second conductive path.

[0029] The vehicle-mounted cutoff current supply device is capable of causing current to flow from the voltage conversion unit to the capacitor, thereby charging the capacitor, before the cutoff condition is satisfied. Furthermore, when the cutoff condition is satisfied, the current from the capacitor flows to the current input unit via the first conductive path and the drive unit. In other words, when the cutoff condition is satisfied, the vehicle-mounted cutoff current supply device is capable of rapidly performing a cutoff operation by the circuit breaker using the current from the capacitor and the current from the voltage conversion unit. Furthermore, when the cutoff condition is satisfied, the output voltage of the voltage conversion unit increases, enabling a more rapid cutoff operation by the circuit breaker.

[0030] [Details of the embodiments of the present disclosure]

[0031] <First embodiment>

[0032] 1. Overview of In-Vehicle System 1

[0033] exist Figure 1, an in-vehicle system 1 including a vehicle-mounted cutoff current supply device 10 according to a first embodiment is shown. In the following description, the in-vehicle cutoff current supply device 10 is also referred to as the cutoff current supply device 10. The in-vehicle system 1 is a system mounted on a vehicle and capable of supplying power to various loads. The vehicle equipped with the in-vehicle system 1 may be, for example, an electric vehicle, a plug-in hybrid vehicle, a hybrid vehicle, or an engine vehicle, but may also be other types of vehicles.

[0034] The in-vehicle system 1 includes a power supply unit 2 , a circuit breaker 3 , and a current cutoff device 10 .

[0035] The power supply unit 2 is comprised of, for example, a battery. The battery may be a secondary battery such as a lead-acid battery or a lithium-ion battery, or may be another type of battery. The high-potential terminal of the battery is electrically connected to the third conductive path 83. The low-potential terminal of the battery is electrically connected to the fourth conductive path 84. When fully charged, the battery applies a predetermined DC voltage between the third conductive path 83 and the fourth conductive path 84.

[0036] The circuit breaker 3 performs a shutoff operation to shut off the power path 9 in response to the current flowing to the current input unit 7. The power path 9 is a conductive path for transmitting electric power. The purpose of the power path 9 is not limited, and for example, it can be configured as a conductive path for supplying electric power to a vehicle-mounted load. The power path 9 has a first power path 9A connected to one side of the circuit breaker 3 and a second power path 9B connected to the other side of the circuit breaker 3. The first power path 9A and the second power path 9B are short-circuited to each other when the circuit breaker 3 is in the on state, and are insulated from each other when the circuit breaker 3 is in the off state. Figure 1 , the connection destination on the opposite side of the circuit breaker 3 in the first power path 9A and the second power path 9B is omitted. The power path 9 is a conductive path to which a voltage higher than the voltage applied between the third conductive path 83 and the fourth conductive path 84 is applied, for example.

[0037] The circuit breaker 3 is configured as a pyrotechnic circuit breaker. As a pyrotechnic circuit breaker, a well-known pyrotechnic fuse or other powder fuse can be preferably used. The circuit breaker 3 has a current input portion 7, conductor portions 8A, 8B, 8C, an igniter 3A, and a displacement portion (not shown). The current input portion 7 has a first terminal portion 7A and a second terminal portion 7B. When the drive portion 14 described later is in an allowed state, the current input portion 7 allows current to flow from the first terminal portion 7A to the second terminal portion 7B. The current input portion 7 is insulated from the power circuit 9. The conductor portion 8A is a terminal connected to the first power circuit 9A and short-circuited with the first power circuit 9A. The conductor portion 8B is a terminal connected to the second power circuit 9B and short-circuited with the second power circuit 9B. The conductor portion 8C is a conductor that short-circuits the conductor portion 8A and the conductor portion 8B.

[0038] The igniter 3A functions by generating a small explosion when current flows from the first terminal 7A to the second terminal 7B, and this explosion causes the displaceable portion to move. More specifically, the igniter 3A functions by generating a small explosion when the integrated value of the current supplied to the igniter 3A (i.e., the current supplied to the current input portion 7) reaches a certain level, causing this explosion to cause the displaceable portion to move. The displaceable portion functions by being held in a predetermined position until an explosion occurs in the igniter 3A (when the conductors 8A, 8B, and 8C are short-circuited). If an explosion occurs in the igniter 3A, the explosion causes the displaceable portion to move toward the conductor 8C, severing the conductor 8C and causing the device to disconnect.

[0039] Thus, the circuit breaker 3 performs a shutoff operation to shut off the power path 9 in response to current flowing to the current input unit 7. More specifically, the circuit breaker 3 performs a shutoff operation to shut off the power path 9 when the integrated value of the current supplied to the current input unit 7 reaches a certain level.

[0040] 2. Structure of the Cut-off Current Supply Device 10

[0041] The current supply cutoff device 10 is used in the vehicle-mounted system 1 and is a device that allows the current supplied from the power supply unit 2 to flow to the current input unit 7 when a cutoff condition is met. The cutoff condition may be, for example, the current flowing through the power path 9 exceeding a threshold current, the voltage of the power path 9 falling below a threshold voltage, or other conditions.

[0042] The cutoff current supply device 10 includes a voltage conversion unit 11 , a capacitor 12 , a signal generation unit 13 , a drive unit 14 , a voltage detection circuit 15 , a parallel switch 16 , and a control unit 17 .

[0043] The voltage converter 11 is provided between the power supply 2 and the drive unit 14. The voltage converter 11 performs a conversion operation, converting the voltage input from the power supply 2 side and applying an output voltage between the first conductive path 81 and the second conductive path 82. The voltage input from the power supply 2 side is the voltage applied between the third conductive path 83 and the fourth conductive path 84. The voltage converter 11 steps up or steps down the voltage input from the power supply 2 side and applies an output voltage between the first conductive path 81 and the second conductive path 82. The voltage converter 11 causes the current from the power supply 2 to flow to the first conductive path 81. The voltage converter 11 is a DC-DC converter. The DC-DC converter can be either a non-insulated or an isolated type.

[0044] exist Figure 1In the example shown, the voltage converter 11 is a boost circuit that performs a step-up operation, boosting the voltage input from the power supply 2 and applying an output voltage between the first conductive path 81 and the second conductive path 82. More specifically, the voltage converter 11 is a non-insulated step-up converter. It includes an inductor 11A and a switching element 11B. In this embodiment, the switching element 11B is comprised of a FET (Field Effect Transistor). However, the switching element 11B may also be comprised of a semiconductor switch other than a FET. The switching element 11B switches on and off in response to a control signal with a predetermined duty cycle supplied to its input (specifically, its gate). One end of the inductor 11A is electrically connected to the third conductive path 83. The other end of the inductor 11A is electrically connected to the first conductive path 81 and one end (specifically, its drain) of the switching element 11B. The other end (specifically, its source) of the switching element 11B is electrically connected to the fourth conductive path 84 and the second conductive path 82. The larger the duty ratio of the control signal supplied to the switching element 11B, the higher the output voltage of the voltage converter 11. The duty ratio is the ratio of the on-time to the cycle. The control signal is, for example, a PWM (Pulse Width Modulation) signal.

[0045] The capacitor 12 is provided between the voltage converter 11 and the driver 14. One end of the capacitor 12 is electrically connected to the first conductive path 81. The other end of the capacitor 12 is electrically connected to the second conductive path 82. When the voltage converter 11 performs a conversion operation, the capacitor 12 is charged by a current supplied from the voltage converter 11 via the first conductive path 81.

[0046] The signal generator 13 outputs an indication signal when the cutoff condition is met. The signal generator 13 determines whether the cutoff condition is met and outputs an indication signal if the cutoff condition is met. For example, the signal generator 13 may determine that the cutoff condition is met when the current flowing through the power path 9 exceeds a threshold current, or when the voltage of the power path 9 falls below a threshold voltage. The indication signal is an on signal that switches the drive switches 14A and 14B and the parallel switch 16 to the on state. The on signal is, for example, a high-level signal. The indication signal is provided to the drive unit 14 and the parallel switch 16.

[0047] When the disconnection condition is satisfied, the signal generator 13 applies an instruction signal to the common line 13A. The instruction signal is supplied to the driver 14 via first branch lines 13B and 13C branching from the common line 13A. The instruction signal is supplied to the parallel switch 16 via second branch line 13D branching from the common line 13A.

[0048] Furthermore, signal generator 13 outputs a standby signal when the disconnection condition is not met. The standby signal is an off signal that maintains drive switches 14A and 14B and parallel switch 16 in the off state. The off signal is, for example, a low-level signal. The standby signal is provided to drive unit 14 and parallel switch 16.

[0049] The driver 14 is provided between the power supply 2 and the current input unit 7 of the circuit breaker 3. The driver 14 is provided between the first conductive path 81 and the current input unit 7 of the circuit breaker 3. When the cutoff condition is met, the driver 14 causes the current supplied from the first conductive path 81 to flow toward the current input unit 7. When an instruction signal is provided, the driver 14 causes the current supplied from the first conductive path 81 to flow toward the current input unit 7. The driver 14 switches between an enabled state, which allows current to flow from the first conductive path 81 to the current input unit 7, and a disabled state, which blocks current from flowing from the first conductive path 81 to the current input unit 7. Before the cutoff condition is met, the driver 14 is in the disabled state and switches to the enabled state when the cutoff condition is met. The driver 14 switches to the enabled state when an instruction signal is provided. By switching to the enabled state, the driver 14 causes the current supplied from the first conductive path 81 to flow toward the current input unit 7.

[0050] The drive unit 14 has drive switches 14A and 14B. The drive switches 14A and 14B can be composed of semiconductor switches such as FETs (Field Effect Transistors) or mechanical switches with contacts. The drive switch 14A is arranged between the first conductive path 81 and the first terminal portion 7A. One end of the drive switch 14A is electrically connected to the first conductive path 81. The other end of the drive switch 14A is electrically connected to the first terminal portion 7A. The drive switch 14B is arranged between the second conductive path 82 and the second terminal portion 7B. One end of the drive switch 14B is electrically connected to the second conductive path 82. The other end of the drive switch 14B is electrically connected to the second terminal portion 7B. The drive switches 14A and 14B are switched to the on state by receiving an instruction signal. When the drive switch 14A is in the on state, the first conductive path 81 is electrically connected to the first terminal portion 7A. When the drive switch 14B is in the on state, the second conductive path 82 is electrically connected to the second terminal portion 7B. When an instruction signal is supplied to the drive switches 14A and 14B, the drive unit 14 causes the current supplied from the first conductive path 81 to flow toward the current input unit 7. Furthermore, the drive unit 14 is in a cutoff state when the drive switches 14A and 14B are in an off state, and is in an enabling state when the drive switches 14A and 14B are in an on state.

[0051] The voltage detection circuit 15 detects the voltage between the first conductive path 81 and the second conductive path 82 and outputs a signal indicating the detected value. The voltage detection circuit 15 divides the voltage between the first conductive path 81 and the second conductive path 82 and outputs the divided voltage. The voltage detection circuit 15 includes a first resistor section 15A, a second resistor section 15B, and an output line 15C. One end of the first resistor section 15A is electrically connected to the first conductive path 81. The other end of the first resistor section 15A is electrically connected to one end of the second resistor section 15B. The other end of the second resistor section 15B is electrically connected to the second conductive path 82. The output line 15C is electrically connected to the connecting portion between the other end of the first resistor section 15A and one end of the second resistor section 15B. The output line 15C is electrically connected to the control unit 17. The voltage detection circuit 15 outputs the voltage divided by the first resistor section 15A and the second resistor section 15B through the output line 15C.

[0052] The parallel switch 16 is provided in parallel with the second resistor 15B. One end of the parallel switch 16 is electrically connected to the output line 15C, and the other end of the parallel switch 16 is electrically connected to the second conductive path 82. The parallel switch 16 can be formed by a semiconductor switch such as a FET (Field Effect Transistor), or a mechanical switch having contacts. When the cutoff condition is met, the parallel switch 16 is provided with an instruction signal and switches to the on state. When the parallel switch 16 is in the on state, current flows from the first conductive path 81 to the second conductive path 82 via the parallel switch 16. When the parallel switch 16 is in the on state, the output line 15C is electrically connected to the second conductive path 82, thereby short-circuiting the output line 15C with the second conductive path 82.

[0053] The control unit 17 controls the voltage converter 11 (more specifically, the switching element 11B) by providing a control signal (e.g., a PWM (Pulse Width Modulation) signal) to the voltage converter 11 (more specifically, the switching element 11B). The control unit 17 performs feedback control of the voltage converter 11 so that the output voltage reaches the target voltage. The control unit 17 is, for example, a general-purpose logic IC that performs this feedback control.

[0054] The control unit 17 starts the above-mentioned feedback control when the cut-off condition is not satisfied. The state in which the cut-off condition is not satisfied refers to the state before the cut-off condition is satisfied. The control unit 17 starts the feedback control when the start condition is satisfied. The start condition may be, for example, the satisfaction of the vehicle's start condition, or other conditions. The control unit 17 may also determine that the vehicle's start condition is satisfied when the start switch is switched to the on state. The start switch is, for example, an ignition switch, a power switch, etc. For example, when the start condition is satisfied, the control unit 17 receives an instruction from an external ECU (Electronic Control Unit) and starts the above-mentioned feedback control.

[0055] The voltage of output line 15C is input to control unit 17. In other words, a signal representing the voltage between first conductive path 81 and second conductive path 82 is input to control unit 17. Control unit 17 determines the output voltage of voltage converter 11 based on the voltage of output line 15C. In the feedback control described above, control unit 17 controls voltage converter 11 based on the output voltage determined by the voltage of output line 15C so that the output voltage reaches the target voltage. For example, control unit 17 determines a duty ratio based on the deviation between the output voltage determined by the voltage of output line 15C and the target voltage, and sets the determined duty ratio. In the feedback control described above, control unit 17 sets a larger duty ratio as the output voltage determined by the voltage of output line 15C decreases relative to the target voltage. The output voltage of voltage converter 11 is determined by the voltage of output line 15C, the resistance value of first resistor 15A, and the resistance value of second resistor 15B. The output voltage of voltage converter 11 is determined, for example, by the following equation (1).

[0056] Output voltage = voltage of output line 15C × R2 / (R1+R2)…Equation (1)

[0057] R1 is the resistance value of the first resistor section 15A, and R2 is the resistance value of the second resistor section 15B.

[0058] The control unit 17 supplies a control signal of the set duty ratio to the switching element 11B.

[0059] When the cutoff condition is met, control unit 17 increases the output voltage of voltage converter 11. When the cutoff condition is met, the instruction signal output from signal generator 13 is supplied to parallel switch 16. Parallel switch 16 switches to the on state upon receiving the instruction signal. As a result, output line 15C is short-circuited to second conductive path 82 via parallel switch 16. This causes the voltage input from output line 15C to control unit 17 to drop sharply, causing the output voltage determined by control unit 17 to drop sharply, leading to a sharp increase in the duty cycle set by control unit 17. Consequently, the output voltage of voltage converter 11 rises sharply.

[0060] 3. Operation Example of Cutting Off the Current Supply Device 10

[0061] The control unit 17 starts the above-mentioned feedback control when the above-mentioned starting condition is met. As a result, the voltage conversion unit 11 starts the above-mentioned conversion action. When the voltage conversion unit 11 performs the conversion action, the current from the power supply unit 2 is supplied to the first conductive path 81 and the capacitor 12, and the capacitor 12 is charged. The output voltage of the voltage conversion unit 11 rises in a manner close to the target voltage. Moreover, the output voltage of the voltage conversion unit 11 is maintained near the target voltage when it approaches the target voltage. A voltage corresponding to the output voltage of the voltage conversion unit 11 is applied to one end of the drive switch 14A. The state in which the capacitor 12 is fully charged and the output voltage of the voltage conversion unit 11 is close to the target voltage becomes a standby state waiting for the cut-off condition to be met. During this period, the control unit 17 continues the feedback control. In addition, from the time the starting condition is met until the cut-off condition is met, the parallel switch 16 is maintained in the disconnected state.

[0062] When the disconnection condition is met in the standby state, the signal generator 13 determines that the disconnection condition has been met and outputs an instruction signal. Upon receiving the instruction signal, the driver 14 switches to the enabled state, allowing the current supplied from the first conductive path 81 to flow toward the current input unit 7. Consequently, the current from the voltage converter 11 and the current from the capacitor 12 flow toward the current input unit 7. Furthermore, the parallel switch 16 switches to the on state upon receiving the instruction signal. As described above, the output voltage of the voltage converter 11 rises sharply, suppressing any decrease in the output current from the voltage converter 11.

[0063] The current supplied to the current input unit 7 flows to the igniter 3A. When the integrated value of the current flowing to the igniter 3A reaches a certain level, the circuit breaker 3 performs the above-mentioned interruption operation.

[0064] 4. Effect Examples

[0065] The on-vehicle cutoff current supply device 10 begins feedback control by the control unit 17 before the cutoff condition is met, and when the cutoff condition is met, current flows from the first conductive path 81 to the current input unit 7 of the circuit breaker 3. Therefore, when the cutoff condition is met, the on-vehicle cutoff current supply device 10 can immediately flow the current supplied from the voltage conversion unit 11 to the current input unit 7 of the circuit breaker 3. Furthermore, the control unit 17 increases the output voltage when the cutoff condition is met. Therefore, the on-vehicle cutoff current supply device 10 can suppress a decrease in the output voltage and, consequently, a decrease in the current flowing to the current input unit 7, when the cutoff condition is met. As a result, the cutoff operation by the circuit breaker 3 is swiftly performed.

[0066] Furthermore, if the target voltage is set higher to increase the output voltage before the cutoff condition is met, high-voltage components must be used for components such as the driver 14 (e.g., the driver switches 14A and 14B), leading to concerns about increased costs. In contrast, the in-vehicle cutoff current supply device 10 increases the output voltage of the voltage converter 11 after the cutoff condition is met, thus minimizing the risk of such cost increases.

[0067] When the cutoff condition is met, the vehicle-mounted cutoff current supply device 10 short-circuits the output line 15C and the second conductive path 82. Therefore, when the cutoff condition is met, the control unit 17 rapidly reduces the voltage input from the output line 15C, rapidly increasing the set duty cycle. This causes the output voltage of the voltage converter 11 to rapidly increase. In other words, the vehicle-mounted cutoff current supply device 10 can control the control unit 17 to rapidly increase the output voltage of the voltage converter 11 when the cutoff condition is met, without incorporating the control unit 17 with a structure for determining whether the cutoff condition has been met or a structure for performing processing corresponding to the cutoff condition being met.

[0068] If the driver 14 and the parallel switch 16 operate based on the results of the cutoff condition determination by different determination units, there is a possibility that the parallel switch 16 may not operate even if the driver 14 operates, or the operation timing of the driver 14 and the parallel switch 16 may be offset. In contrast, in the vehicle-mounted cutoff current supply device 10, both the driver 14 and the parallel switch 16 operate in response to the instruction signal from the signal generator 13. Therefore, when current flows from the driver 14 to the current input unit 7 in response to the establishment of the cutoff condition, the vehicle-mounted cutoff current supply device 10 can more reliably increase the output voltage of the voltage converter 11.

[0069] The on-vehicle cutting current supply device 10 can flow current from the voltage conversion unit 11 to the capacitor 12, charging the capacitor 12, before the cutting condition is satisfied. Furthermore, when the cutting condition is satisfied, the current from the capacitor 12 flows to the current input unit 7 via the first conductive path 81 and the driver 14. In other words, when the cutting condition is satisfied, the on-vehicle cutting current supply device 10 can rapidly perform a cutting operation by the circuit breaker 3 using the current from the capacitor 12 and the current from the voltage conversion unit 11. Furthermore, when the cutting condition is satisfied, the output voltage of the voltage conversion unit 11 increases, enabling a more rapid cutting operation by the circuit breaker 3.

[0070] Furthermore, the vehicle-mounted cutoff current supply device 10 may be configured to cause the circuit breaker 3 to perform a cutoff operation solely by the current from the capacitor 12. With this configuration, the circuit breaker 3 can be more quickly cutoff by applying the current from the voltage conversion unit 11. Furthermore, with this configuration, it is also easier to cope with a decrease in the supply current caused by, for example, deterioration of the capacitor 12.

[0071] The vehicle-mounted cutoff current supply device 10 may be configured to cut off the circuit breaker 3 only by the current from the voltage converter 11. With this configuration, the circuit breaker 3 can be cut off more quickly by applying the current from the capacitor 12.

[0072] Alternatively, the in-vehicle cutoff current supply device 10 may be configured such that the circuit breaker 3 does not perform a cutoff operation using only the current from the capacitor 12 or the voltage conversion unit 11, but can perform a cutoff operation using current from both the capacitor 12 and the voltage conversion unit 11. This configuration makes it easier to reduce the capacitance of the capacitor 12 compared to a configuration in which the circuit breaker 3 performs a cutoff operation using only the current from the capacitor 12.

[0073] <Second embodiment>

[0074] In the second embodiment, an example is described in which the output voltage of the voltage converter is increased by increasing the duty ratio of the output control signal when the cutoff condition is satisfied.

[0075] The vehicle-mounted system 201 of the second embodiment includes a vehicle-mounted cutoff current supply device 210 instead of the vehicle-mounted cutoff current supply device 10 of the first embodiment. The vehicle-mounted system 201 is the same as the vehicle-mounted system 1 of the first embodiment in other respects.

[0076] The vehicle-mounted cutoff current supply device 210 includes a control unit 217 instead of the control unit 17 of the first embodiment. The vehicle-mounted cutoff current supply device 210 does not include the parallel switch 16. The vehicle-mounted cutoff current supply device 210 is the same as the vehicle-mounted cutoff current supply device 10 of the first embodiment in other respects.

[0077] The control unit 217 is mainly composed of, for example, a microcomputer, and includes an information processing unit such as a CPU, and a storage unit such as a ROM and a RAM.

[0078] The control unit 217 performs the same operations as the control unit 17 of the first embodiment. Furthermore, after initiating the aforementioned feedback control, the control unit 217 determines whether the cutoff condition has been met. If the cutoff condition has been met, the control unit 217 increases the duty cycle of the output control signal, thereby increasing the output voltage of the voltage converter 11. More specifically, the control unit 217 increases the duty cycle of the output control signal compared to the duty cycle of the control signal that causes the output voltage to reach the target voltage.

[0079] The duty cycle after the increase may be a predetermined value, a value determined based on the duty cycle when the cutoff condition is satisfied, or another value. The value determined based on the duty cycle when the cutoff condition is satisfied may be, for example, a value obtained by adding a predetermined addition value to the duty cycle when the cutoff condition is satisfied, a value obtained by multiplying the duty cycle by a predetermined multiplication value, or a value calculated using another calculation formula.

[0080] As described above, the in-vehicle cutoff current supply device 210 of the second embodiment can increase the output voltage of the voltage converter 11 by increasing the duty cycle of the control signal output from the control unit 217 when the cutoff condition is met. Therefore, the in-vehicle cutoff current supply device 210 can easily simplify the structure for increasing the output voltage from the voltage converter 11.

[0081] <Third embodiment>

[0082] In the third embodiment, an example is described in which the control unit increases the target voltage when the cutoff condition is satisfied, thereby increasing the output voltage of the voltage converter. Components identical to those in the first embodiment are denoted by the same reference numerals in the third embodiment, and detailed descriptions thereof are omitted.

[0083] The vehicle-mounted system 301 of the third embodiment includes a vehicle-mounted cutoff current supply device 310 instead of the vehicle-mounted cutoff current supply device 10 of the first embodiment. The vehicle-mounted system 301 is the same as the vehicle-mounted system 1 of the first embodiment in other respects.

[0084] The vehicle-mounted cutoff current supply device 310 includes a control unit 317 instead of the control unit 17 of the first embodiment. The vehicle-mounted cutoff current supply device 310 does not include the parallel switch 16. The vehicle-mounted cutoff current supply device 310 is the same as the vehicle-mounted cutoff current supply device 10 of the first embodiment in other respects.

[0085] The control unit 317 is mainly composed of, for example, a microcomputer, and includes an information processing unit such as a CPU, and a storage unit such as a ROM and a RAM.

[0086] The control unit 317 performs the same operations as the control unit 17 of the first embodiment. Furthermore, after starting the aforementioned feedback control, the control unit 317 determines whether the cutoff condition has been met. If the cutoff condition has been met, the control unit 317 increases the target voltage, thereby increasing the output voltage of the voltage converter 11.

[0087] The target voltage after the increase may be a predetermined value, a value determined based on the target voltage when the cutoff condition is satisfied, or another value. The value determined based on the target voltage when the cutoff condition is satisfied may be, for example, a value obtained by adding a predetermined addition value to the target voltage when the cutoff condition is satisfied, a value obtained by multiplying the target voltage by a predetermined multiplication value, or a value calculated using another calculation formula.

[0088] As described above, the vehicle-mounted cutoff current supply device 310 of the third embodiment can increase the output voltage of the voltage conversion unit 11 by increasing the target voltage when the cutoff condition is met. Therefore, the vehicle-mounted cutoff current supply device 310 of the third embodiment can easily simplify the structure for increasing the output voltage of the voltage conversion unit 11.

[0089] <Other Implementation Methods>

[0090] The present disclosure is not limited to the embodiments described above and illustrated in the accompanying drawings. For example, the features of the embodiments described above or below can be combined in any manner to the extent that they do not conflict. In addition, any feature in the embodiments described above or below can be omitted unless explicitly stated as an essential feature. Furthermore, the embodiments described above can also be modified as follows.

[0091] In the first embodiment described above, only the parallel switch 16 is provided in parallel with the second resistor 15B. However, any configuration is acceptable as long as current flows from the first conductive path 81 to the second conductive path 82 via the parallel switch 16 when the parallel switch 16 is in the on state. Alternatively, a structure in which another element is connected to the parallel switch 16 and provided in parallel with the second resistor 15B may be employed. Examples of the other element include a resistor, a diode, and the like.

[0092] In the first embodiment described above, the drive unit 14 and the parallel switch 16 are configured to operate based on the result of the disconnection condition being determined by the same determination unit (signal generating unit 13 ). However, they may be configured to operate based on the result of the disconnection condition being determined by different determination units.

[0093] In each of the above-mentioned embodiments, the capacitor may not be provided.

[0094] The determination of whether the cutoff condition is satisfied may be performed inside the vehicle-mounted cutoff current supply device 10 or outside the vehicle-mounted cutoff current supply device 10. When the determination of whether the cutoff condition is satisfied is performed outside the vehicle-mounted cutoff current supply device 10, the vehicle-mounted cutoff current supply device 10 can perform an operation accompanying the satisfaction of the cutoff condition by inputting a signal from the outside when it is determined that the cutoff condition is satisfied.

[0095] 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 indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0096] Label Description 1…In-vehicle system 2…Power supply 3…Circuit Breaker 3A…igniter 7…Current input 7A…First terminal 7B…Second terminal 8A…Conductor 8B…Conductor 8C…Conductor 9…Electric Power Road 9A…First Electric Power Road 9B…Second Electric Power Road 10…In-vehicle current cutoff device 11…Voltage conversion unit 11A...Inductor 11B…Switching element 12…Capacitor 13…Signal generating unit 13A...shared line 13B…First Branch Line 13C…First branch line 13D…Second branch line 14…Drive unit 14A...driving switch 14B...Drive switch 15…Voltage detection circuit 15A...First resistor 15B...Second resistor 15C... output line 16…parallel switch 17…Control Unit 81…First conductive circuit 82…Second conductive circuit 83…Third conductive circuit 84…Fourth conductive circuit 201…In-vehicle system 210…In-vehicle current cut-off device 217…Control Department 301…In-vehicle system 310…In-vehicle current cut-off device 317…Control Department.

Claims

1. A vehicle-mounted current supply cutoff device, used in a vehicle-mounted system, the vehicle-mounted system comprising a power supply unit and a circuit breaker, the circuit breaker performing a cutoff operation to cut off a power path in response to current flowing to a current input unit, the vehicle-mounted current supply cutoff device causing current supplied from the power supply unit to flow to the current input unit when a cutoff condition is met, wherein: The vehicle-mounted current cutoff supply device comprises: a voltage conversion unit that converts a voltage input from the power supply unit and applies an output voltage between the first conductive path and the second conductive path; a driving unit configured to cause the current supplied from the first conductive path to flow toward the current input unit when the cutoff condition is satisfied; and a control unit that performs feedback control for controlling the voltage conversion unit so that the output voltage becomes a target voltage; The control unit starts the feedback control in a state where the cutoff condition is not satisfied, and increases the output voltage of the voltage conversion unit when the cutoff condition is satisfied.

2. The vehicle-mounted cutoff current supply device according to claim 1, wherein: The voltage conversion unit includes a switching element that performs on-off operations in response to a control signal provided thereto, and the output voltage increases as the duty ratio of the control signal provided to the switching element increases. The vehicle-mounted cutoff current supply device further includes a voltage detection circuit configured to detect a voltage between the first conductive path and the second conductive path. The voltage detection circuit has: a first resistor portion, one end of which is electrically connected to the first conductive circuit; a second resistor portion, one end of which is electrically connected to the other end of the first resistor portion, and the other end of which is electrically connected to the second conductive circuit; and an output line electrically connected to a connection portion between the other end of the first resistor section and one end of the second resistor section, The control unit receives the voltage of the output line as input, sets a larger duty ratio as the output voltage determined based on the voltage of the output line is smaller than the target voltage, and supplies the control signal of the set duty ratio to the switching element. The vehicle-mounted cutoff current supply device further includes a parallel switch provided in parallel with the second resistor unit. When the cutoff condition is satisfied, the parallel switch is switched to the on state, and current flows from the first conductive path side to the second conductive path side via the parallel switch.

3. The vehicle-mounted cutoff current supply device according to claim 2, wherein: When the cutoff condition is met, the parallel switch is switched to an on state, and the output line and the second conductive path are short-circuited.

4. The vehicle-mounted cutoff current supply device according to claim 2 or claim 3, wherein: The vehicle-mounted cutoff current supply device includes a signal generating unit that outputs an instruction signal when the cutoff condition is satisfied. The instruction signal output from the signal generating unit is provided to the driving unit and the parallel switch. When the instruction signal is supplied to the driving unit, the driving unit supplies the current supplied from the first conductive path to the current input unit side. The parallel switch is switched to an on state when the instruction signal is provided.

5. The vehicle-mounted cutoff current supply device according to claim 1, wherein: The voltage conversion unit includes a switching element that performs on-off operations in response to a control signal provided thereto, and the output voltage increases as the duty ratio of the control signal provided to the switching element increases. The control unit is configured to output the control signal to control the voltage conversion unit. When the cutoff condition is satisfied, the control unit increases the duty ratio of the output control signal to thereby increase the output voltage of the voltage conversion unit.

6. The vehicle-mounted cutoff current supply device according to claim 1, wherein: The control unit increases the target voltage when the cutoff condition is satisfied, thereby increasing the output voltage of the voltage conversion unit.

7. The vehicle-mounted cutoff current supply device according to any one of claims 1 to 3, wherein: The vehicle-mounted cutoff current supply device includes a capacitor having one end electrically connected to the first conductive path and the other end electrically connected to the second conductive path.

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