Circuit break 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

Technical Field

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

Background Art

[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 when the battery is disconnected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <~ For example, when a surge or noise occurs in a circuit, there is a concern that the squib may malfunction based on the surge or noise. Here, a surge refers to a voltage or current that varies steeply so as to rise, depending on the operating conditions of a power source or a load connected to the power source. Also, noise refers to a voltage or current generated in a circuit due to so-called common-mode noise or the influence of external electromagnetic waves.

[0005] The present disclosure has been made based on the above circumstances, and an object thereof is to provide a cutoff control device that can prevent malfunction due to at least noise.

Means for Solving the Problems

[0006] [[ID=~45]] An electric current sensor having a shunt resistor provided in a conductive path and a differential amplifier that amplifies the voltage at both ends of the shunt resistor, a magnetic sensor that detects a magnetic field generated by an electric current flowing through the conductive path, and at least two of a voltage sensor that detects the voltage of the conductive path, An overcurrent detection unit is provided corresponding to each of the at least two 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: [Effects of the Invention]

[0007] According to this disclosure, at least malfunctions due to noise can be prevented. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a block diagram schematically showing the configuration of the in-vehicle system of Embodiment 1. [Figure 2] Figure 2 is a circuit diagram showing an example of the configuration of the first sensor, which is a current sensor. [Figure 3] Figure 3 is a circuit diagram showing an example of the configuration of the second sensor, which is a voltage sensor. [Figure 4] Figure 4 is a flowchart showing an example of the operation of a circuit breaker control device. [Figure 5] Figure 5 is a circuit diagram showing an example of the configuration of the third sensor, which is a magnetic sensor. [Modes for carrying out the invention]

[0009] [Description of Embodiments in this Disclosure] The embodiments of this disclosure are listed and illustrated below.

[0010] (1) A current sensor having a shunt resistor provided in the conductive path and a differential amplifier that amplifies the voltage across the shunt resistor, a magnetic sensor that detects a magnetic field generated by the current flowing through the conductive path, and at least two of the following: An overcurrent detection unit is provided corresponding to each of the at least two 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:

[0011] In the circuit breaker control device of (1), the current sensor, voltage sensor, and magnetic sensor react differently to noise in the conductive path. Therefore, when noise occurs in a conductive path equipped with at least two of these sensors, the reactions of each sensor will differ, 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 conductive path enters an overcurrent state, the effects of the overcurrent state are reflected simultaneously in the detection signals, and overcurrent detection is performed. The department Based on these detection signals, the control unit can detect an overcurrent condition and switch the circuit breaker to the off state. In this way, it becomes possible to appropriately control the switching of the circuit breaker to the off state while eliminating the influence of noise. Here, an overcurrent condition in the conductive path means a state in which the magnitude of the current flowing through the conductive path is constantly at an overcurrent level.

[0012] (2) The circuit breaker 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 cutoff control device of (2), when a voltage surge occurs in the conductive path, the voltage sensor outputs a detection signal reflecting the voltage surge, and the current sensor and the magnetic sensor output detection signals that do not reflect the voltage surge. Also, when a current surge occurs in the conductive path, the current sensor and the magnetic sensor output detection signals reflecting the current surge, and the voltage sensor outputs a detection signal that does not reflect the current surge. That is, it is difficult for the detection signals output from each sensor to simultaneously reflect the influence of the surge. Therefore, according to this configuration, malfunction due to a surge occurring in the conductive path can be prevented.

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

[0015] In the cutoff control device of (3), the current sensor is easily affected by common-mode noise and is less affected by external electromagnetic waves. In contrast, the magnetic sensor is less affected by common-mode noise and is easily affected by external electromagnetic waves. Therefore, by using the current sensor and the magnetic sensor as the two sensors, it is possible to make it difficult for the influence of noise to be simultaneously reflected in the detection signal and suppress malfunction due to noise.

[0016] (4) Each overcurrent detection unit 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 the comparators at the same time. Furthermore, the cutoff control device according to any one of (1) to (3) includes a drive circuit that switches the cutoff unit to the cutoff state when the instruction signal is input.

[0017] In the cutoff control device of (4), since the control unit outputs an instruction signal using an AND circuit, which is a logic circuit, the cutoff unit can be switched to the cutoff state earlier.

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

[0019] The tripping control device in (5) can detect an overcurrent condition using other non-faulting sensors and switch the tripping unit to the tripped state even if some sensors fail. Note that the range outside the normal range includes values ​​greater than the upper limit and values ​​smaller than the lower limit of the normal range.

[0020] <Embodiment 1> [In-vehicle system configuration] The in-vehicle system 100 shown in Figure 1 is a system mounted on vehicle C. The in-vehicle system 100 comprises a battery 91, a load 70, a conductive path 80, and a circuit breaker control device 10. The in-vehicle system 100 supplies power from the battery 91 to the load 70.

[0021] The battery 91 can be, for example, a lead-acid battery or a lithium-ion battery. The load 70 is an in-vehicle electrical device, and includes electric components, various ECUs, ADAS components, etc. 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 circuit breaker control device] The circuit breaker control device 10 includes 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 circuit breaker 13.

[0023] The first sensor 11A and the second sensor 11B use different methods. For example, the first sensor 11A is a current sensor that includes 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 it as a detection signal V1, as shown in Figure 2.

[0024] As shown in Figure 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, and outputs a value obtained by dividing the detected voltage (output voltage) as a detection signal V2. Alternatively, the detection signal V2 may be configured to output the voltage of the second conductive path 80B itself.

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

[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 in correspondence with the first sensor 11A and the second sensor 11B, respectively. The first overcurrent detection unit 12A and the second overcurrent detection unit 12B have 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 threshold value, which is a first threshold value Th1. When the detection signal V1 exceeds the first threshold value Th1, the first overcurrent detection unit 12A detects that an overcurrent is flowing 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 the second threshold Th2. When the detection signal V2 falls below the second threshold Th2, the second overcurrent detection unit 12B detects that an overcurrent is flowing through the second conductive path 80B. When the second overcurrent detection unit 12B detects that the second conductive path 80B is in an overcurrent state, it outputs an overcurrent signal C2. In this way, the overcurrent detection unit 12 detects the overcurrent state of the conductive path 80 based on the detection signals V1 and V2 output from the corresponding sensors.

[0028] The determination unit 16 is composed of, for example, an MCU (Micro Controller Unit) or a hardware circuit. The determination unit 16 is configured to receive a detection signal V1 applied to the first signal line 17A and a detection signal V2 applied to the second signal line 17B. For example, the determination unit 16 is configured to determine 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 in itself, and to determine whether the first sensor 11A is malfunctioning. Furthermore, the determination unit 16 is configured to determine 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 in itself, and to determine whether the second sensor 11B is malfunctioning.

[0029] For example, a malfunction of the first sensor 11A could be a state where the shunt resistor 11D is open, resulting in an infinite resistance, or a short circuit, causing the resistance to become so small that it can be considered zero. A malfunction of the second sensor 11B could be a state where resistors 11F and 11G are open, resulting in an infinite resistance, or a short circuit, causing the resistance to become so small that it can be considered zero.

[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 the range outside the normal range includes values ​​greater than the upper limit (first upper limit Cu1) and values ​​smaller than the lower limit (first lower limit Cd1) of the normal range. If the detection signal V1 is less than or equal to the first upper limit Cu1 and greater than or equal to 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 period of 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 the range outside the normal range includes values ​​greater than the upper limit (second upper limit Cu2) and values ​​smaller than the lower limit (second lower limit Cd2) of the normal range. If the detection signal V2 is less than or equal to the second upper limit Cu2 and greater than or equal to 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 composed of, for example, 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 overcurrent signals C1 and C2 from the first overcurrent detection unit 12A and the second overcurrent detection unit 12B, respectively, and receives the first fault signal M1 and the second fault signal M2 from the determination unit 16.

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

[0034] When the first fault signal M1 is input from the determination unit 16 and the second fault signal M2 is not input, and the control unit 14 receives an overcurrent signal C2 from the second overcurrent detection unit 12B, the control unit 14 outputs an instruction signal Sg1. The control unit 14 does not output an instruction signal Sg1 if the overcurrent signal C2 is not input from the second overcurrent detection unit 12B. In other words, when the first fault signal M1 is input, the control unit 14 outputs an instruction 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 and the first fault signal M1 is not input, and the control unit 14 receives an overcurrent signal C1 from the first overcurrent detection unit 12A, the control unit 14 outputs an instruction signal Sg1. The control unit 14 does not output an instruction signal Sg1 if the overcurrent signal C1 is not input from the first overcurrent detection unit 12A. In other words, when the second fault signal M2 is input, the control unit 14 outputs an instruction signal Sg1 based on the overcurrent signal C1 from the first overcurrent detection unit 12A. That is, the control unit 14 does not use the overcurrent signal based on the sensor determined to be faulty by the determination unit 16, but controls the output of the instruction signal Sg1 using the overcurrent signal based on the sensor that is not faulty.

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

[0037] The interruption unit 13 is, for example, a gunpowder-type fuse such as a well-known pyrofuse (registered trademark). The interruption unit 13 is provided, for example, in the second conductive path 80B. The interruption unit 13 physically disconnects the second conductive path 80B in response to the input of a drive signal D1 from the drive circuit 15, switching from an allowable state to an interrupted state. The allowable state is a state in which current is allowed to flow through the second conductive path 80B. The interrupted state is a state in which current is blocked from flowing through the second conductive path 80B. After entering the interrupted state, the interruption unit 13 cannot return to the allowable state. The interruption unit 13 may be configured to allow return. A configuration that allows return is, for example, a switch. The switch may be a mechanical switch with contacts, or a semiconductor switch such as a MOSFET or IGBT.

[0038] [An example of the operation of a circuit breaker control device] Next, an example of the operation of the circuit breaker control device 10 will be described. For example, the conductive path 80 enters an overcurrent state (i.e., the magnitude of the current in the conductive path 80 is constantly overcurrent). In this case, the first sensor 11A, which is a current sensor, detects the current flowing through the conductive path 80 and outputs a detection signal V1 that reflects the overcurrent state to the first signal line 17A. The comparator 12C of the first overcurrent detection unit 12A outputs an overcurrent signal C1 when the detection signal V1 exceeds the first threshold Th1.

[0039] When the conductive path 80 enters 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 that reflects 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 Th2.

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

[0041] Next, an example of the operation of the interruption 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, causing a sharp change in the voltage applied to it. The second sensor 11B, which is a voltage sensor, then outputs a detection signal V2 to the second signal line 17B that reflects the voltage surge. When a voltage surge occurs in the conductive path 80, the magnitude of the current flowing through it does not change. Therefore, the detection signal V1 output from the first sensor 11A, which is a current sensor, does not reflect the voltage surge in the conductive path 80. Consequently, the first overcurrent detection unit 12A does not output an overcurrent signal C1 because the detection signal V1 does not exceed the first threshold Th1. The second overcurrent detection unit 12B outputs an overcurrent signal C2 because the detection signal V2 falls below the second threshold Th2. Thus, only the overcurrent signal C2 is input to the control unit 14. Therefore, since the AND circuit 14A does not output the instruction signal Sg1, the drive signal D1 is not output from the drive circuit 15.

[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 a sharp fluctuation in the current flowing through it. In this case, the first sensor 11A, which is a current sensor, outputs a detection signal V1 to the first signal line 17A that reflects the current surge or common-mode noise. 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, 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 even if it occurs in the conductive path 80. Consequently, 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 Th2. The first overcurrent detection unit 12A outputs an overcurrent signal C1 because the detection signal V1 exceeds the first threshold Th1. Thus, only the overcurrent signal C1 is input to the control unit 14. Therefore, the AND circuit 14A does not output the instruction signal Sg1, and thus the drive circuit 15 does not output the drive signal D1. In other words, if 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 instruction signal Sg1 is not output.

[0044] Next, with reference to Figure 4, an example of the operation of the shut-off control device 10 used to determine whether 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 or not the first sensor 11A is malfunctioning. Specifically, the determination unit 16 determines whether or not the detection signal V1 output from the first sensor 11A 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., outside the normal range). In step S1, if the detection signal V1 is less than or equal to the first upper limit Cu1 and greater than or equal to the first lower limit Cd1 (i.e., within the normal range), the determination unit 16 determines that the first sensor 11A is not malfunctioning (No in step S1) and 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 remained 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., outside the normal range) (Yes in step S1). If so, the determination unit 16 outputs a first fault signal M1 indicating that the first sensor 11A is malfunctioning, and proceeds to step S2.

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

[0048] When the process moves to step S3, the control unit 14 determines whether or not an overcurrent signal C2 is input from the second overcurrent detection unit 12B. If the control unit 14 determines in step S3 that no overcurrent signal C2 is input from the second overcurrent detection unit 12B (No in step S3), the process shown in Figure 4 is terminated.

[0049] In step S3, the control unit 14 determines that an overcurrent signal C2 has been input from the second overcurrent detection unit 12B (Yes in step S3). Then, the process moves to step S4, where the control unit 14 outputs an instruction signal Sg1, and the process shown in Figure 4 ends. 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] When the process moves to step S5, the determination unit 16 determines whether or not the second sensor 11B is malfunctioning. Specifically, the determination unit 16 determines whether or not the detection signal V2 output from the second sensor 11B has remained above the second upper limit Cu2 or below the second lower limit Cd2 for a predetermined period of time or longer (i.e., outside the normal range). In step S5, if the detection signal V2 is below the second upper limit Cu2 and above the second lower limit Cd2 (i.e., within the normal range), the determination unit 16 determines that the second sensor 11B is not malfunctioning (No in step S5) and 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 for a predetermined period of time or longer (i.e., outside the normal range) (Yes in step S5). The determination unit 16 then outputs a second fault signal M2 indicating that the second sensor 11B is malfunctioning, and proceeds to step S6.

[0052] When the process moves to step S6, the control unit 14 determines whether or not an overcurrent signal C1 is input from the first overcurrent detection unit 12A. If the control unit 14 determines in step S6 that no overcurrent signal C1 is input from the first overcurrent detection unit 12A (No in step S6), the process shown in Figure 4 is terminated.

[0053] In step S6, the control unit 14 determines that an 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 the process shown in Figure 4 ends. 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] When the process moves to step S7, the control unit 14 determines whether an overcurrent signal C1 is input from the first overcurrent detection unit 12A and an overcurrent signal C2 is input from the second overcurrent detection unit 12B. If the control unit 14 determines in step S7 that no overcurrent signal C1 is input from the first overcurrent detection unit 12A, or no overcurrent signal C2 is input from the second overcurrent detection unit 12B (No in step S7), the process shown in Figure 4 is terminated.

[0055] In step S7, the control unit 14 determines that an overcurrent signal C1 is input from the first overcurrent detection unit 12A and an overcurrent signal C2 is 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 terminates the process shown in Figure 4.

[0056] Next, we will illustrate the effects of this configuration. The circuit breaker control device 10 comprises a first sensor 11A and a second sensor 11B, an overcurrent detection unit 12, a circuit breaker unit 13, and a control unit 14. The first sensor 11A is a current sensor having 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. The overcurrent detection unit 12 is provided in correspondence with each of the two sensors and detects the overcurrent state of the conductive path 80 based on detection signals V1 and V2 output from the corresponding sensors. The circuit breaker unit 13 switches from an allowable state, which permits current to flow through the conductive path 80, to a circuit breaker state, which blocks the flow of current. When multiple overcurrent detection units 12 detect an overcurrent state at the same time, the control unit 14 outputs an instruction signal Sg1 to switch the circuit breaker unit 13 to the circuit breaker state.

[0057] In this configuration, the first sensor 11A and the second sensor 11B react differently when a surge or common-mode noise occurs in the conductive path 80. Therefore, when a surge or common-mode noise occurs in the conductive path 80 where the first sensor 11A and the second sensor 11B are installed, the reactions of each sensor differ, making it difficult for the effects of the surge and common-mode noise to be reflected simultaneously in the detection signals V1 and V2 output from each sensor. In contrast, when the conductive path 80 enters an overcurrent state, the effects of the overcurrent state are reflected simultaneously 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 cutoff unit 13 to the cutoff state. In this way, it becomes possible to appropriately control the cutoff unit 13 to the cutoff state while eliminating the effects of the surge and common-mode noise. Here, the statement that the conductive path 80 is in an overcurrent state means that the magnitude of the current flowing through the conductive path 80 is constantly in an overcurrent state.

[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, and the first sensor 11A outputs a detection signal V1 that does not reflect the voltage surge. Also, 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, and 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 reflect the effects of surges and common-mode noise at the same time. Therefore, with this configuration, malfunctions caused by surges and common-mode noise occurring in the conductive path 80 can be prevented.

[0059] Each overcurrent detection unit 12 has comparators 12C and 12D to which detection signals V1 and V2 are input. Comparator 12C outputs an overcurrent signal C1 when detection signal V1 exceeds a first threshold Th1. Comparator 12D outputs an overcurrent signal C2 when detection signal V2 falls below a second threshold Th2. The control unit 14 has an AND circuit 14A that outputs an instruction signal Sg1 when overcurrent signals C1 and C2 are input from all comparators 12C and 12D at the same time. Furthermore, it includes a drive circuit 15 that switches the cutoff unit 13 to the cutoff state when the instruction signal Sg1 is input. Since the control unit 14 is configured to output the instruction signal Sg1 using the AND circuit 14A, which is a logic circuit, it can switch the cutoff unit 13 to the cutoff state at an earlier stage.

[0060] The circuit breaker control device 10 includes signal lines 17 and a determination unit 16. The signal lines 17 are provided corresponding to the first sensor 11A and the second sensor 11B, and detection signals V1 and V2 output from the corresponding sensors are applied to them. The determination unit 16 determines whether the detection signals V1 and V2 applied to each signal line 17 are within the 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 circuit breaker 13 to the circuit breaker 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 overcurrent condition can be detected by the other non-faulting sensors, and the circuit breaker 13 can be switched to the circuit breaker state.

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

[0062] Unlike Embodiment 1, the control unit and the determination unit may be configured as a single microcomputer.

[0063] Unlike Embodiment 1, a configuration may be provided in the conductive path in addition to the current sensor and voltage sensor, including a magnetic sensor. In this case, the control unit may output an instruction signal when overcurrent signals are input from these sensors at the same time. For example, the third sensor 11H, which is a magnetic sensor, is a known Hall element that is provided non-contact with respect to the second conductive path 80B, positioned near the second conductive path 80B, as shown in Figure 5, and detects the magnetic field generated by the current flowing through the second conductive path 80B. The third sensor 11H outputs a detection signal V3 to the third signal line 17C, which is part of the signal line 17, and 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 has a comparator 12F. When the detection signal V3 exceeds the third threshold Th3, which is a threshold, the comparator 12F outputs an overcurrent signal C3 to the AND circuit of the control unit. When overcurrent signals are input to the AND circuit from all sensors, an instruction signal is output from the AND circuit.

[0064] Unlike Embodiment 1, the configuration may use a third sensor 11H (magnetic sensor) as shown in Figure 5 instead of a current sensor. In other words, the configuration may include two sensors: a third sensor 11H which is a magnetic sensor and a second sensor 11B which is a voltage sensor.

[0065] Unlike Embodiment 1, the configuration may use a third sensor 11H (magnetic sensor) as shown in Figure 5 instead of a voltage sensor. In other words, 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 reflected in the detection signals V1 and V3 at the same time, thereby suppressing malfunctions due to noise. In this configuration, the determination unit outputs a first fault signal when it determines that the first sensor 11A is faulty, and outputs a third fault signal when it determines that the third sensor 11H is faulty. The control unit controls the output of the instruction signal using an overcurrent signal from a sensor that is not faulty, rather than using an overcurrent signal from a sensor that has been determined to be faulty by the determination unit.

[0066] Operational amplifiers may be used as the first overcurrent detection unit and the second overcurrent detection unit.

[0067] Unlike Embodiment 1, the interruption section may be provided in the first conductive path. Furthermore, the first sensor and the second sensor may also be provided in the first conductive path. [Explanation of symbols]

[0068] 10 ... Interruption 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... Comparators 12E ...Third overcurrent detection unit 13 ... Blocking section 14 ... Control Unit 14A ... AND circuit 15 ... Drive circuit 16...judgment section 17 ... Signal line 17A…1st signal line 17B…Second signal line 17C...Third signal line 70 ... load 80 ... Conductive circuit 80A ... First conductive path 80B…Second conductive path 91... Battery 100 ... In-vehicle systems 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…1st failure signal M2…Second failure signal Sg1…Instruction signal Th1…First threshold (threshold) Th2…Second threshold (threshold) Th3…Third threshold (threshold) V1, V2, V3... Detection signals

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. 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.

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