Cutoff control device

Abstract

A cutoff control device (10) comprises: a first sensor (11A) that is a current sensor having a shunt resistor (11D) provided in a conductive path (80) and a differential amplifier (11E) for amplifying the voltage across both ends of the shunt resistor (11D) and a second sensor (11B) that is a voltage sensor for detecting the voltage of the conductive path (80); overcurrent detection units (12) that are provided corresponding to the respective two sensors and detect the overcurrent state of the conductive path (80) on the basis of detection signals (V1, V2) output from the corresponding sensors; a cutoff unit (13) that switches from an allowable state in which current is allowed to flow to the conductive path (80) to a cutoff state in which the current is cut off; and a control unit (14) that outputs an instruction signal (Sg1) that switches the cutoff unit (13) to the cutoff state when the plurality of overcurrent detection units (12) detect the overcurrent state at the same time.

Description

Shut-off control device

[0001] The present disclosure relates to a shutoff control device.

[0002] Patent Document 1 discloses an airbag ignition circuit that connects a backup capacitor to a power source and can reliably supply power to a squib even if the battery is disconnected.

[0003] Japanese Patent Application Laid-Open No. 2005-88748

[0004] For example, if a surge or noise occurs in a circuit, there is a risk that the squib may malfunction. Here, "surge" refers to voltage or current that fluctuates sharply depending on the operating conditions of the power supply or the load connected to the power supply. Furthermore, "noise" refers to so-called common mode noise, or voltage or current that occurs in a circuit due to the influence of external electromagnetic waves.

[0005] The present disclosure has been made in light of the above-mentioned circumstances, and aims to provide a cutoff control device that can prevent malfunction due to at least noise.

[0006] 1. A cutoff control device comprising: at least two of a current sensor having a shunt resistor provided in a conductive path and a differential amplifier that amplifies the voltage across the shunt resistor, a magnetic sensor that detects a magnetic field generated by a current flowing through the conductive path, and a voltage sensor that detects the voltage of the conductive path; an overcurrent detection unit provided corresponding to each of the at least two sensors and that detects an overcurrent state of the conductive path based on a detection signal output from the corresponding sensor; a cutoff unit that switches from an allowable state that allows current to flow through the conductive path to a cutoff state that cuts off the current; and a control unit that outputs an instruction signal to switch the cutoff unit to the cutoff state when a plurality of the overcurrent detection units simultaneously detect the overcurrent state.

[0007] According to the present disclosure, malfunctions due to noise can at least be prevented.

[0008] Fig. 1 is a block diagram schematically showing the configuration of an in-vehicle system according to a first embodiment. Fig. 2 is a circuit diagram showing an example of the configuration of a first sensor which is a current sensor. Fig. 3 is a circuit diagram showing an example of the configuration of a second sensor which is a voltage sensor. Fig. 4 is a flowchart showing an example of the operation of an interruption control device. Fig. 5 is a circuit diagram showing an example of the configuration of a third sensor which is a magnetic sensor.

[0009] [Description of Embodiments of the Present Disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] (1) A cutoff control device comprising: at least two of a current sensor having a shunt resistor provided in a conductive path and a differential amplifier that amplifies the voltage across the shunt resistor, a magnetic sensor that detects a magnetic field generated by a current flowing through the conductive path, and a voltage sensor that detects the voltage of the conductive path; an overcurrent detection unit provided corresponding to each of the at least two sensors and that detects an overcurrent state of the conductive path based on a detection signal output from the corresponding sensor; a cutoff unit that switches from an allowable state that allows current to flow through the conductive path to a cutoff state that cuts off the current; and a control unit that outputs an instruction signal to switch the cutoff unit to the cutoff state when a plurality of the overcurrent detection units simultaneously detect the overcurrent state.

[0011] In the circuit breaker control device (1), the current sensor, voltage sensor, and magnetic sensor respond differently when noise occurs in the conduction path. Therefore, when noise occurs in a conduction path that includes at least two of these sensors, the sensors respond differently, making it difficult for the effects of the noise to be reflected simultaneously in the detection signals output from each sensor. In contrast, when the conduction path experiences an overcurrent, the effects of the overcurrent are reflected simultaneously in the detection signals. The overcurrent detection unit 12 detects the overcurrent based on these detection signals, and the control unit switches the circuit breaker to the circuit breaker state. This allows appropriate control to switch the circuit breaker to the circuit breaker state after eliminating the effects of noise. Here, a circuit breaker in an overcurrent state refers to a state in which the magnitude of the current flowing through the conduction path remains constantly overcurrent.

[0012] (2) The cutoff control device according to (1), wherein the at least two sensors include at least one of the current sensor and the magnetic sensor, and the voltage sensor.

[0013] In the interruption control device of (2), when a voltage surge occurs in the conduction path, the voltage sensor outputs a detection signal that reflects the voltage surge, while the current sensor and magnetic sensor output detection signals that do not reflect the voltage surge. Furthermore, when a current surge occurs in the conduction path, the current sensor and magnetic sensor output detection signals that reflect the current surge, while the voltage sensor outputs a detection signal that does not reflect the current surge. In other words, the effects of the surge are unlikely to be reflected simultaneously in the detection signals output by each sensor. Therefore, this configuration can prevent malfunctions caused by surges occurring in the conduction path.

[0014] (3) The cutoff control device according to (1), wherein the at least two sensors include the current sensor and the magnetic sensor.

[0015] In the interruption control device of (3), the current sensor is susceptible to common-mode noise but not to external electromagnetic waves. In contrast, the magnetic sensor is not susceptible to common-mode noise but is susceptible to external electromagnetic waves. Therefore, by using a current sensor and a magnetic sensor as the two sensors, it is possible to make it difficult for the effects of noise to be reflected in the detection signal at the same time, thereby enabling a configuration that suppresses malfunctions due to noise.

[0016] (4) A cutoff control device according to any one of (1) to (3), wherein each of the overcurrent detection units has a comparator to which the detection signal is input, the comparator outputs an overcurrent signal when the detection signal exceeds a threshold value, the control unit has an AND circuit that outputs the instruction signal when the overcurrent signals are input from all of the comparators at the same time, and further includes a drive circuit that switches the cutoff unit to the cutoff state when the instruction signal is input.

[0017] In the tripping control device of (4), the control unit is configured to output the instruction signal using an AND circuit, which is a logic circuit, so that the tripping unit can be switched to the tripping state more quickly.

[0018] (5) A cutoff control device according to any one of (1) to (3), comprising: a signal line provided corresponding to each of the at least two sensors, to which the detection signal output from the corresponding sensor is applied; and a judgment unit that judges whether the detection signal applied to each of the signal lines is within a normal range, wherein when the judgment unit judges that the detection signal of some of the signal lines is outside the normal range and the detection signal of other of the signal lines is within the normal range, the control unit switches the cutoff unit to the cutoff state based only on the detection signal applied to the other of the signal lines.

[0019] In the case of (5), even if some of the sensors fail, the tripping control device can detect an overcurrent state using the other sensors that are not failing and switch the tripping unit to the tripping state. Note that the value outside the normal range includes values ​​that are greater than the upper limit of the normal range and values ​​that are smaller than the lower limit of the normal range.

[0020] 1 is a system mounted on a vehicle C. The vehicle system 100 includes a battery 91, a load 70, a conductive path 80, and a cutoff control device 10. The vehicle system 100 supplies power from the battery 91 to the load 70.

[0021] The battery 91 may be, for example, a lead-acid battery or a lithium-ion battery. The load 70 is an in-vehicle electrical device, such as an electrically-powered component, various ECUs, or ADAS-targeted components. The conductive path 80 has a first conductive path 80A and a second conductive path 80B. The first conductive path 80A is provided between the positive terminal of the battery 91 and the load 70. The second conductive path 80B is provided between the negative terminal of the battery 91 and the load 70.

[0022] [Configuration of the shutdown control device] The shutdown control device 10 has a first sensor 11A, a second sensor 11B, a signal line 17, an overcurrent detection unit 12, a determination unit 16, a control unit 14, a drive circuit 15, and a shutdown unit 13.

[0023] The first sensor 11A and the second sensor 11B are different in type from each other. For example, as shown in Fig. 2, the first sensor 11A is a current sensor having a shunt resistor 11D provided in the second conductive path 80B and a differential amplifier 11E that amplifies the voltage across the shunt resistor 11D and outputs the amplified voltage as a detection signal V1.

[0024] 3, the second sensor 11B is a voltage sensor that detects the voltage of the second conductive path 80B using two resistors 11F and 11G connected in series, divides the detected voltage (output voltage), and outputs the divided value as the detection signal V2. Alternatively, the second sensor 11B may be configured to output the voltage of the second conductive path 80B itself as the detection signal V2.

[0025] As shown in FIG. 1 , the signal line 17 includes a first signal line 17A and a second signal line 17B. The first signal line 17A is connected to a differential amplifier 11E (see FIG. 2 ), and receives a detection signal V1 output from the differential amplifier 11E. The second signal line 17B is connected to a connection point between the second sensor 11B and two resistors 11F and 11G (see FIG. 3 ), and receives a detection signal V2 obtained by dividing the voltage of the second conductive path 80B. In this way, the signal lines 17 are provided corresponding to the first sensor 11A and the second sensor 11B, respectively, and receive the detection signals V1 and V2 output from the corresponding first sensor 11A and second sensor 11B.

[0026] The overcurrent detection unit 12 includes a first overcurrent detection unit 12A and a second overcurrent detection unit 12B. The first overcurrent detection unit 12A and the second overcurrent detection unit 12B are provided corresponding to the first sensor 11A and the second sensor 11B, respectively. The first overcurrent detection unit 12A and the second overcurrent detection unit 12B include comparators 12C and 12D to which detection signals V1 and V2 are input from the corresponding sensors. The comparator 12C of the first overcurrent detection unit 12A acquires the detection signal V1 detected by the first sensor 11A and compares the acquired detection signal V1 with a first threshold value Th1. When the detection signal V1 exceeds the first threshold value Th1, the first overcurrent detection unit 12A detects an overcurrent state in which an overcurrent flows through the second conductive path 80B. When the first overcurrent detection unit 12A detects that the second conductive path 80B is in an overcurrent state, it outputs an overcurrent signal C1.

[0027] The comparator 12D of the second overcurrent detection unit 12B acquires the detection signal V2 detected by the second sensor 11B and compares the acquired detection signal V2 with a second threshold value Th2. When the detection signal V2 falls below the second threshold value Th2, the second overcurrent detection unit 12B detects an overcurrent state in which an overcurrent flows through the second conductive path 80B. When the second overcurrent detection unit 12B detects an overcurrent state in the second conductive path 80B, it outputs an overcurrent signal C2. In this way, the overcurrent detection unit 12B detects an overcurrent state in the conductive path 80 based on the detection signals V1 and V2 output from the corresponding sensors.

[0028] The determination unit 16 is configured, for example, by an MCU (Micro Controller Unit) or a hardware circuit. The determination unit 16 receives the detection signal V1 applied to the first signal line 17A and the detection signal V2 applied to the second signal line 17B. For example, the determination unit 16 determines whether the detection signal V1 falls within a normal range defined by a first upper limit value Cu1 and a first lower limit value Cd1 stored therein, thereby determining whether the first sensor 11A is malfunctioning. Furthermore, the determination unit 16 determines whether the detection signal V2 falls within a normal range defined by a second upper limit value Cu2 and a second lower limit value Cd2 stored therein, thereby determining whether the second sensor 11B is malfunctioning.

[0029] For example, a state in which the first sensor 11A has failed may be a state in which the shunt resistor 11D is open and the resistance value becomes infinite, or a state in which the shunt resistor 11D is short-circuited and the resistance value becomes small enough to be considered 0. A state in which the second sensor 11B has failed may be a state in which the resistors 11F and 11G are open and the resistance value becomes infinite, or a state in which the resistors 11F and 11G are short-circuited and the resistance value becomes small enough to be considered 0.

[0030] For example, if the detection signal V1 remains greater than the first upper limit Cu1 or less than the first lower limit Cd1 for a predetermined period of time or longer (i.e., the detection signal V1 is outside the normal range), the determination unit 16 determines that the first sensor 11A is faulty. The determination unit 16 then outputs a first fault signal M1 indicating that the first sensor 11A is faulty. Note that "outside the normal range" includes values ​​greater than the upper limit (first upper limit Cu1) and less than the lower limit (first lower limit Cd1) of the normal range. If the detection signal V1 is equal to or less than the first upper limit Cu1 and equal to or greater than the first lower limit Cd1 (i.e., the detection signal V1 is within the normal range), the determination unit 16 determines that the first sensor 11A is not faulty and does not output the first fault signal M1.

[0031] If the detection signal V2 remains greater than the second upper limit Cu2 or less than the second lower limit Cd2 for a predetermined time or longer (i.e., the detection signal V2 is outside the normal range), the determination unit 16 determines that the second sensor 11B is faulty. The determination unit 16 then outputs a second fault signal M2 indicating that the second sensor 11B is faulty. Note that "outside the normal range" includes values ​​greater than the upper limit (second upper limit Cu2) and less than the lower limit (second lower limit Cd2) of the normal range. If the detection signal V2 is equal to or less than the second upper limit Cu2 and equal to or greater than the second lower limit Cd2 (i.e., the detection signal V2 is within the normal range), the determination unit 16 determines that the second sensor 11B is not faulty and does not output the second fault signal M2.

[0032] The control unit 14 is configured, for example, by a hardware circuit or an MCU (Micro Controller Unit). The control unit 14 has an AND circuit 14A. The AND circuit 14A is a known logic circuit. The control unit 14 receives both the overcurrent signals C1 and C2 from the first overcurrent detection unit 12A and the second overcurrent detection unit 12B, and also receives a first fault signal M1 and a second fault signal M2 from the determination unit 16.

[0033] When neither the first fault signal M1 nor the second fault signal M2 is input from the determination unit 16, the AND circuit 14A outputs an indication signal Sg1 if both the overcurrent signals C1 and C2 are input from the first overcurrent detection unit 12A and the second overcurrent detection unit 12B at the same time. The AND circuit 14A does not output an indication signal Sg1 if only one of the overcurrent signals C1 and C2 is input from the first overcurrent detection unit 12A and the second overcurrent detection unit 12B (i.e., at different times rather than simultaneously). The AND circuit 14A does not output an indication signal Sg1 if neither the overcurrent signal C1 nor C2 is input from the first overcurrent detection unit 12A or the second overcurrent detection unit 12B.

[0034] When the first fault signal M1 is input from the determination unit 16 but the second fault signal M2 is not input, and the overcurrent signal C2 is input from the second overcurrent detection unit 12B to the control unit 14, the control unit 14 outputs the indication signal Sg1. The control unit 14 does not output the indication signal Sg1 unless the overcurrent signal C2 is input from the second overcurrent detection unit 12B. In other words, when the first fault signal M1 is input, the control unit 14 outputs the indication signal Sg1 based on the overcurrent signal C2 from the second overcurrent detection unit 12B.

[0035] When the second fault signal M2 is input from the determination unit 16 but the first fault signal M1 is not input, and the overcurrent signal C1 is input from the first overcurrent detection unit 12A to the control unit 14, the control unit 14 outputs the indication signal Sg1. The control unit 14 does not output the indication signal Sg1 unless the overcurrent signal C1 is input from the first overcurrent detection unit 12A. In other words, when the second fault signal M2 is input, the control unit 14 outputs the indication signal Sg1 based on the overcurrent signal C1 from the first overcurrent detection unit 12A. In other words, the control unit 14 does not use the overcurrent signal based on the sensor determined to be faulty by the determination unit 16, but uses the overcurrent signal based on the sensor that is not faulty to control the output of the indication signal Sg1.

[0036] The drive circuit 15 is configured as, for example, a known drive circuit, and outputs a drive signal D1 when an instruction signal Sg1 is input from the control unit 14.

[0037] The interrupter 13 may be, for example, a pyrotechnic fuse such as a known pyrofuse (registered trademark). The interrupter 13 is provided, for example, in the second conductive path 80B. The interrupter 13 physically cuts off the second conductive path 80B in response to input of the drive signal D1 from the drive circuit 15, switching from a permissive state to a blocked state. The permissive state is a state in which current is permitted to flow through the second conductive path 80B. The blocked state is a state in which current is blocked from flowing through the second conductive path 80B. After entering the blocked state, the interrupter 13 cannot return to the permissive state. The interrupter 13 may be configured to be reversible. An example of a reversible configuration is a switch. The switch may be a mechanical switch having contacts, or a semiconductor switch such as a MOSFET or an IGBT.

[0038] [Example of Operation of Shutdown Control Device] Next, an example of operation of the shutdown control device 10 will be described. For example, the conductive path 80 enters an overcurrent state (i.e., a state in which the magnitude of the current in the conductive path 80 is constantly an overcurrent). When this occurs, the first sensor 11A, which is a current sensor, detects the current flowing in the conductive path 80 and outputs a detection signal V1 reflecting the overcurrent state to the first signal line 17A. When the detection signal V1 exceeds the first threshold value Th1, the comparator 12C of the first overcurrent detection unit 12A outputs an overcurrent signal C1.

[0039] When the conductive path 80 is in an overcurrent state, the voltage applied to the conductive path 80 (i.e., the potential difference between the first conductive path 80A and the second conductive path 80B) decreases. The second sensor 11B, which is a voltage sensor, outputs a detection signal V2 reflecting the voltage applied to the conductive path 80 to the second signal line 17B. The comparator 12D of the second overcurrent detection unit 12B outputs an overcurrent signal C2 when the detection signal V2 falls below the second threshold value Th2.

[0040] Overcurrent signals C1 and C2 are input from all comparators 12C and 12D to the AND circuit 14A of the control unit 14 at the same time. The AND circuit 14A then outputs an instruction signal Sg1. When the instruction signal Sg1 is input, the drive circuit 15 outputs a drive signal D1 to the cutoff unit 13, switching the cutoff unit 13 from a permissive state to a cutoff state. In other words, when the first overcurrent detection unit 12A and the second overcurrent detection unit 12B simultaneously detect an overcurrent state, the control unit 14 outputs the instruction signal Sg1 to switch the cutoff unit 13 to the cutoff state.

[0041] Next, an example of the operation of the cutoff control device 10 when a surge or common mode noise occurs in the conductive path 80 will be described.

[0042] [When a voltage surge occurs in the conductive path] For example, a voltage surge occurs in the conductive path 80, where the voltage applied to the conductive path 80 fluctuates rapidly. Then, the second sensor 11B, which is a voltage sensor, outputs a detection signal V2 reflecting the voltage surge to the second signal line 17B. When a voltage surge occurs in the conductive path 80, the magnitude of the current flowing through the conductive path 80 does not fluctuate. Therefore, even if a voltage surge occurs in the conductive path 80, the detection signal V1 output from the first sensor 11A, which is a current sensor, does not reflect the voltage surge. Therefore, the first overcurrent detection unit 12A does not output an overcurrent signal C1 because the detection signal V1 does not exceed the first threshold value Th1. The second overcurrent detection unit 12B outputs an overcurrent signal C2 because the detection signal V2 is below the second threshold value Th2. Thus, only the overcurrent signal C2 is input to the control unit 14. Therefore, the AND circuit 14A does not output the instruction signal Sg1, and the drive circuit 15 does not output the drive signal D1.

[0043] [When a Current Surge or Common-Mode Noise Occurs in the Conductive Path] For example, a current surge or common-mode noise occurs in the conductive path 80, causing the current flowing through the conductive path 80 to fluctuate sharply. In this case, the first sensor 11A, which is a current sensor, outputs a detection signal V1 reflecting the current surge or common-mode noise to the first signal line 17A. When a current surge or common-mode noise occurs in the conductive path 80, the voltage applied to the conductive path 80 does not fluctuate. Therefore, even if a current surge or common-mode noise occurs in the conductive path 80, the detection signal V2 output from the second sensor 11B, which is a voltage sensor, does not reflect the current surge or common-mode noise. Therefore, the second overcurrent detection unit 12B does not output an overcurrent signal C2 because the detection signal V2 does not fall below the second threshold value Th2. The first overcurrent detection unit 12A outputs an overcurrent signal C1 because the detection signal V1 exceeds the first threshold value Th1. In this way, only the overcurrent signal C1 is input to the control unit 14. Therefore, the AND circuit 14A does not output the indication signal Sg1, and therefore the drive signal D1 is not output from the drive circuit 15. In other words, when a surge or common mode noise occurs in the conductive path 80, the overcurrent signals C1 and C2 are not input to the AND circuit 14A at the same time, and therefore the indication signal Sg1 is not output.

[0044] Next, with reference to FIG. 4, an example of the operation of the cutoff control device 10 used to determine whether or not the first sensor 11A and the second sensor 11B are malfunctioning will be described.

[0045] First, in step S1, the determination unit 16 determines whether the first sensor 11A is faulty. Specifically, the determination unit 16 determines whether the detection signal V1 output from the first sensor 11A has been greater than the first upper limit Cu1 or less than the first lower limit Cd1 (i.e., outside the normal range) for a predetermined time or longer. In step S1, if the detection signal V1 is equal to or less than the first upper limit Cu1 and equal to or greater than the first lower limit Cd1 (i.e., within the normal range), the determination unit 16 determines that the first sensor 11A is not faulty (No in step S1), and the process proceeds to step S5.

[0046] In step S1, the determination unit 16 determines that the detection signal V1 output from the first sensor 11A has been greater than the first upper limit value Cu1 or less than the first lower limit value Cd1 (i.e., outside the normal range) for a predetermined time or longer (Yes in step S1). Then, the determination unit 16 outputs a first failure signal M1 indicating that the first sensor 11A has failed, and the process proceeds to step S2.

[0047] In step S2, the determination unit 16 determines whether the second sensor 11B is faulty. Specifically, the determination unit 16 determines whether the detection signal V2 output from the second sensor 11B has remained greater than the second upper limit Cu2 or less than the second lower limit Cd2 (i.e., outside the normal range) for a predetermined time or longer. In step S2, if the detection signal V2 is equal to or less than the second upper limit Cu2 and equal to or greater than the second lower limit Cd2 (i.e., within the normal range), the determination unit 16 determines that the second sensor 11B is not faulty (No in step S2), and the process proceeds to step S3. In step S2, if the determination unit 16 determines that the detection signal V2 has remained greater than the second upper limit Cu2 or less than the second lower limit Cd2 (i.e., outside the normal range) for a predetermined time or longer (Yes in step S2), the process in FIG. 4 ends.

[0048] In step S3, the control unit 14 determines whether or not the overcurrent signal C2 has been input from the second overcurrent detection unit 12B. If the control unit 14 determines in step S3 that the overcurrent signal C2 has not been input from the second overcurrent detection unit 12B (No in step S3), the process in FIG. 4 ends.

[0049] In step S3, the control unit 14 determines that the overcurrent signal C2 has been input from the second overcurrent detection unit 12B (Yes in step S3). Then, the process proceeds to step S4, where the control unit 14 outputs an instruction signal Sg1 and ends the process in Fig. 4. In this way, when the determination unit 16 determines that the detection signal V1 of the first signal line 17A is outside the normal range and the detection signal V2 of the second signal line 17B is within the normal range, the control unit 14 switches the cutoff unit 13 to the cutoff state based only on the detection signal V2 applied to the second signal line 17B.

[0050] In step S5, the determination unit 16 determines whether the second sensor 11B is faulty. Specifically, the determination unit 16 determines whether the detection signal V2 output from the second sensor 11B has remained greater than the second upper limit Cu2 or less than the second lower limit Cd2 (i.e., outside the normal range) for a predetermined time or longer. In step S5, if the detection signal V2 is equal to or less than the second upper limit Cu2 and equal to or greater than the second lower limit Cd2 (i.e., within the normal range), the determination unit 16 determines that the second sensor 11B is not faulty (No in step S5), and the process proceeds to step S7.

[0051] In step S5, the determination unit 16 determines that the detection signal V2 output from the second sensor 11B has remained greater than the second upper limit Cu2 or less than the second lower limit Cd2 (i.e., outside the normal range) for a predetermined time or longer (Yes in step S5). Then, the determination unit 16 outputs a second failure signal M2 indicating that the second sensor 11B is malfunctioning, and the process proceeds to step S6.

[0052] In step S6, the control unit 14 determines whether or not the overcurrent signal C1 has been input from the first overcurrent detection unit 12A. If the control unit 14 determines in step S6 that the overcurrent signal C1 has not been input from the first overcurrent detection unit 12A (No in step S6), the process in FIG. 4 ends.

[0053] In step S6, the control unit 14 determines that the overcurrent signal C1 has been input from the first overcurrent detection unit 12A (Yes in step S6). Then, the process proceeds to step S4, where the control unit 14 outputs an instruction signal Sg1 and ends the process in Fig. 4. In this way, when the determination unit 16 determines that the detection signal V2 of the second signal line 17B is outside the normal range and the detection signal V1 of the first signal line 17A is within the normal range, the control unit 14 switches the cutoff unit 13 to the cutoff state based only on the detection signal V1 applied to the first signal line 17A.

[0054] In step S7, the control unit 14 determines whether the overcurrent signal C1 has been input from the first overcurrent detection unit 12A and whether the overcurrent signal C2 has been input from the second overcurrent detection unit 12B. If the control unit 14 determines in step S7 that the overcurrent signal C1 has not been input from the first overcurrent detection unit 12A or the overcurrent signal C2 has not been input from the second overcurrent detection unit 12B (No in step S7), the process in FIG. 4 ends.

[0055] In step S7, the control unit 14 determines that the overcurrent signal C1 has been input from the first overcurrent detection unit 12A and that the overcurrent signal C2 has been input from the second overcurrent detection unit 12B (Yes in step S7). Then, the process proceeds to step S4, where the control unit 14 outputs an instruction signal Sg1, and the process in FIG. 4 ends.

[0056] Next, the effects of this configuration will be illustrated. The interruption control device 10 includes a first sensor 11A, a second sensor 11B, an overcurrent detection unit 12, an interruption unit 13, and a control unit 14. The first sensor 11A is a current sensor including a shunt resistor 11D provided in the conductive path 80 and a differential amplifier 11E that amplifies the voltage across the shunt resistor 11D. The second sensor 11B is a voltage sensor that detects the voltage of the conductive path 80. An overcurrent detection unit 12 is provided corresponding to each of the two sensors and detects an overcurrent state in the conductive path 80 based on detection signals V1 and V2 output from the corresponding sensor. The interruption unit 13 switches from a permissive state that allows current to flow through the conductive path 80 to a cutoff state that cuts off the current. When multiple overcurrent detection units 12 simultaneously detect an overcurrent state, the control unit 14 outputs an instruction signal Sg1 to switch the cutoff unit 13 to the cutoff state.

[0057] With this configuration, the first sensor 11A and the second sensor 11B respond differently to a surge or common-mode noise occurring in the conductive path 80. Therefore, when a surge or common-mode noise occurs in the conductive path 80 on which the first sensor 11A and the second sensor 11B are provided, the sensors respond differently. Therefore, the effects of the surge and common-mode noise are unlikely to be reflected simultaneously in the detection signals V1 and V2 output from the sensors. In contrast, when the conductive path 80 enters an overcurrent state, the effects of the overcurrent state are simultaneously reflected in the detection signals V1 and V2. The overcurrent detection unit 12 detects the overcurrent state based on these detection signals V1 and V2, and the control unit 14 can switch the interrupter 13 to the interruption state. In this way, it is possible to appropriately control the interrupter 13 to the interruption state while eliminating the effects of the surge and common-mode noise. Here, the overcurrent state in the conductive path 80 refers to a state in which the magnitude of the current flowing through the conductive path 80 is constantly and continuously an overcurrent.

[0058] The two sensors include a first sensor 11A, which is a current sensor, and a second sensor 11B, which is a voltage sensor. With this configuration, when a voltage surge occurs in the conductive path 80, the second sensor 11B outputs a detection signal V2 that reflects the voltage surge, while the first sensor 11A outputs a detection signal V1 that does not reflect the voltage surge. Furthermore, when a current surge or common-mode noise occurs in the conductive path 80, the first sensor 11A outputs a detection signal V1 that reflects the current surge or common-mode noise, while the second sensor 11B outputs a detection signal V2 that does not reflect the current surge or common-mode noise. In other words, the detection signals V1 and V2 output from each sensor are less likely to be affected by the surge and common-mode noise simultaneously. Therefore, with this configuration, malfunctions due to surges and common-mode noise occurring in the conductive path 80 can be prevented.

[0059] Each overcurrent detection unit 12 includes a comparator 12C, 12D to which detection signals V1, V2 are input. The comparator 12C outputs an overcurrent signal C1 when the detection signal V1 exceeds a first threshold Th1. The comparator 12D outputs an overcurrent signal C2 when the detection signal V2 falls below a second threshold Th2. The control unit 14 includes an AND circuit 14A that outputs an indication signal Sg1 when the overcurrent signals C1, C2 are simultaneously input from all comparators 12C, 12D. The control unit 14 further includes a drive circuit 15 that switches the cutoff unit 13 to the cutoff state when the indication signal Sg1 is input. The control unit 14 outputs the indication signal Sg1 using the AND circuit 14A, which is a logic circuit, allowing the cutoff unit 13 to be switched to the cutoff state more quickly.

[0060] The trip control device 10 includes signal lines 17 and a determination unit 16. The signal lines 17 are provided corresponding to the first and second sensors 11A and 11B, and receive detection signals V1 and V2 output from the corresponding sensors. The determination unit 16 determines whether the detection signals V1 and V2 applied to each signal line 17 are within a normal range. When the determination unit 16 determines that the detection signals V1 (V2) of some signal lines 17 are outside the normal range and the detection signals V2 (V1) of other signal lines 17 are within the normal range, the control unit 14 switches the trip unit 13 to the trip state based only on the detection signals V2 (V1) applied to the other signal lines 17. With this configuration, even if some sensors fail, the other healthy sensors can detect an overcurrent state and switch the trip unit 13 to the trip state.

[0061] <Other Embodiments> The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0062] Unlike the first embodiment, the control unit and the determination unit may be configured as a single microcomputer.

[0063] Unlike the first embodiment, a magnetic sensor may be provided in addition to the current sensor and voltage sensor in the conductive path. In this case, the control unit may output an instruction signal when overcurrent signals are simultaneously input from these sensors. For example, as shown in FIG. 5 , the third sensor 11H, which is a magnetic sensor, is provided in a non-contact manner with respect to the second conductive path 80B and is a known Hall element disposed near the second conductive path 80B to detect a magnetic field generated by a current flowing through the second conductive path 80B. The third sensor 11H outputs a detection signal V3 to a third signal line 17C, which is part of the signal line 17. Furthermore, a third overcurrent detection unit 12E, which is an overcurrent detection unit 12 to which the detection signal V3 is input, is provided. The third overcurrent detection unit 12E includes a comparator 12F. When the detection signal V3 exceeds a third threshold value Th3, the comparator 12F outputs an overcurrent signal C3 to an AND circuit in the control unit. When the overcurrent signals are input to the AND circuit from all the sensors, the AND circuit outputs an instruction signal.

[0064] Unlike the first embodiment, a configuration may be adopted in which a third sensor 11H (magnetic sensor) shown in Fig. 5 is used instead of the current sensor. In other words, a configuration may be adopted in which two sensors are included: the third sensor 11H, which is a magnetic sensor, and the second sensor 11B, which is a voltage sensor.

[0065] Unlike the first embodiment, a third sensor 11H (magnetic sensor) shown in FIG. 5 may be used instead of the voltage sensor. That is, the two sensors may include a first sensor 11A, which is a current sensor, and a third sensor 11H, which is a magnetic sensor. The first sensor 11A (current sensor) is susceptible to common-mode noise and less susceptible to electromagnetic noise. In contrast, the third sensor 11H (magnetic sensor) is less susceptible to common-mode noise and more susceptible to electromagnetic noise. Therefore, by using the first sensor 11A (current sensor) and the third sensor 11H (magnetic sensor), the influence of noise is less likely to be simultaneously reflected in the detection signals V1 and V3, thereby suppressing malfunctions due to noise. In this configuration, the determination unit outputs a first fault signal if it determines that the first sensor 11A is faulty, and outputs a third fault signal if it determines that the third sensor 11H is faulty. The control unit controls the output of the instruction signal using the overcurrent signal based on the sensor that has not failed, without using the overcurrent signal based on the sensor that has failed determined by the determination unit.

[0066] An operational amplifier may be used as the first overcurrent detection unit and the second overcurrent detection unit.

[0067] Unlike the first embodiment, the interrupter may be provided in the first conduction path. Also, the first sensor and the second sensor may be provided in the first conduction path.

[0068] DESCRIPTION OF SYMBOLS 10...Shutoff control device 11A...First sensor 11B...Second sensor 11D...Shunt resistor 11E...Differential amplifier 11F, 11G...Resistor 11H...Third sensor 12...Overcurrent detection unit 12A...First overcurrent detection unit 12B...Second overcurrent detection unit 12C, 12D, 12F...Comparator 12E...Third overcurrent detection unit 13...Shutoff unit 14...Control unit 14A...AND circuit 15...Drive circuit 16...Determination unit 17...Signal line 17A...First signal line 17B...Second signal line 17C...Third signal line 70...Load 80...Conductive path 80A...First conductive path 80B...Second conductive path 91...Battery 100...In-vehicle system C...Vehicle C1, C2, C3...Overcurrent signal Cd1 ...First lower limit Cd2 ...Second lower limit Cu1 ...First upper limit Cu2 ...Second upper limit D1 ...Drive signal M1 ...First fault signal M2 ...Second fault signal Sg1 ...Indication signal Th1 ...First threshold value (threshold value) Th2 ...Second threshold value (threshold value) Th3 ...Third threshold value (threshold value) V1, V2, V3 ...Detection signal

Claims

1. A current sensor having a shunt resistor provided in a conductive path and a differential amplifier that amplifies the voltage across the shunt resistor, a magnetic sensor that detects the magnetic field generated by the current flowing through the conductive path, and a voltage sensor that detects the voltage of the conductive path, An overcurrent detection unit is provided corresponding to each of the three sensors and detects the overcurrent state of the conductive path based on the detection signal output from the corresponding sensor. A blocking unit that switches from an allowable state in which current is permitted to flow through the conductive path to a blocking state in which current is blocked, A control unit that outputs an instruction signal to switch the cutoff unit to the cutoff state when multiple overcurrent detection units detect the overcurrent state at the same time, A circuit break control device equipped with the following:

2. (delete)

3. (delete)

4. Each of the overcurrent detection units has a comparator to which the detection signal is input. The comparator outputs an overcurrent signal when the detection signal exceeds a threshold. The control unit has an AND circuit that outputs the instruction signal when the overcurrent signal is input from all of the comparators at the same time. Furthermore, the circuit breaker control device according to claim 1, comprising a drive circuit that switches the circuit breaker to the circuit breaker state when the instruction signal is input.