Electric circuit breaker device

Abstract

An electric circuit breaker device (60) is a breaker device for driving a current breaker (20) that is provided on a current path (11) and has control terminals (23a and 23b). The breaker device comprises: a breaker control circuit (40) that, on the basis of a detection signal output from a current detection unit (50) that detects the current flowing through the current path (11), applies a current to the control terminals (23a and 23b) via two cables (44a and 44b) that are DC-connected to the control terminals (23a and 23b); and a current conduction protection unit (30) that suppresses the breakdown current flowing from the control terminals (23a and 23b) toward the breaker control circuit (40) via the two cables (44a and 44b) after a current has been applied to the control terminals (23a and 23b).

Description

Electrical Circuit Breaker

[0001] The present disclosure relates to an electrical circuit interruption device, and more particularly to an electrical circuit interruption device that drives a current interrupter having a control terminal provided on a current path.

[0002] Electrical circuit interrupters are used in electrical circuits mounted on electric vehicles and the like to prevent serious damage by interrupting the electrical circuit (i.e., interrupting the current) in the event of an abnormality such as a short circuit in the load. As an electrical circuit interrupter, technology has been proposed for current interrupters such as pyrofuses that house an igniter, a projectile (piston), a bus bar, and the like within a housing (see Patent Document 1).

[0003] JP 2019-53911 A

[0004] In the technology of Patent Document 1, metal is used for the internal and external structures of the electrical circuit breaker, and when current from a high-voltage source is interrupted, an arc generated at the cut bus bar may cause high voltage to flow into the control terminal of the igniter, potentially destroying the control circuit connected to the control terminal of the igniter (hereinafter, this control circuit may also be referred to as the "circuit breaker control circuit").

[0005] An electrical circuit interruption device according to one embodiment of the present disclosure is an electrical circuit interruption device that is arranged on a current path and drives a current interrupter having a control terminal, and includes: a circuit interruption control circuit that applies current to the control terminal via two cables connected to the control terminal in a DC manner based on a detection signal output from a current detection unit that detects the current flowing through the current path; and a current conduction protection unit that suppresses a breakdown current that flows from the control terminal via the two cables toward the circuit interrupter control circuit after applying current to the control terminal.

[0006] The present disclosure provides an electrical circuit breaker that can prevent a control circuit from being destroyed by a sneak high voltage.

[0007] Fig. 1 is a circuit diagram showing the configuration of an electrical circuit interruption device according to an embodiment. Fig. 2 is a flowchart showing the operation of the electrical circuit interruption device according to the embodiment. Fig. 3 is a diagram showing the interruption operation of a current breaker provided in the electrical circuit interruption device according to the embodiment. Fig. 4 is a circuit diagram showing the configuration of an electrical circuit interruption device according to a first modified example of the embodiment. Fig. 5A is a circuit diagram showing the configuration of an electrical circuit interruption device according to a second modified example of the embodiment. Fig. 5B is a circuit diagram showing another example configuration of the switch control circuit shown in Fig. 5A.

[0008] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that each embodiment described below represents a specific example of the present disclosure. The numerical values, shapes, materials, components, component arrangement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, each figure is not necessarily an exact illustration. In each figure, substantially identical configurations are assigned the same reference numerals, and redundant explanations are omitted or simplified. Furthermore, "connection" means electrical connection, and includes not only cases where two circuit elements are directly connected, but also cases where two circuit elements are indirectly connected with another circuit element inserted between them.

[0009] FIG. 1 is a circuit diagram showing the configuration of an electric circuit interruption device 60 according to an embodiment. The electric circuit interruption device 60 is a device for driving a current interrupter 20 having control terminals 23a and 23b provided on a current path 11. In this embodiment, the electric circuit interruption device 60 includes the current interrupter 20, a current detection unit 50, a current continuity protection unit 30, and a circuit breaker control circuit 40. In addition to the electric circuit interruption device 60, the diagram also shows a power source 10, a current path 11, and a load 12. The current interruption device 20 is also shown in a schematic cross-sectional view. The current interruption device 20 and the current detection unit 50 do not necessarily have to be components of the electric circuit interruption device 60. That is, the electric circuit interruption device 60 may be composed of only the current continuity protection unit 30 and the circuit breaker control circuit 40.

[0010] Furthermore, as shown in FIG. 1 and other figures, the current breaker 20 in this embodiment is disclosed as having two control terminals 23a and 23b. In this disclosure, the two control terminals 23a and 23b may be collectively referred to as the "control terminal (singular)."

[0011] The power supply 10 is a current source that supplies current to a load 12 via a current path 11, and is, for example, a high-voltage (for example, about 400 V) battery mounted on an EV (electric vehicle).

[0012] The load 12 is a load for the current supplied from the power supply 10, and is, for example, an inverter mounted on an EV.

[0013] The current breaker 20 is an active breaker (active fuse) that is provided on the current path 11 on the positive potential side of the power supply 10, has control terminals 23 a and 23 b, and cuts off the current flowing through the current path 11 in response to a signal from outside (drive circuit 43 in Figure 1) when a cutoff signal (specifically, a current) that satisfies predetermined conditions is input to the control terminals 23 a and 23 b. In the present embodiment, current breaker 20 is, for example, a pyrotechnic fuse (also referred to as a pyrotechnic circuit breaker or an irreversible pyrotechnic circuit breaker), and includes: housing 21 including cylinder 21a; control terminals 23a and 23b exposed from housing 21; igniter 22 that burns (i.e., ignites) a contained explosive when a current equal to or greater than a predetermined value is applied to control terminals 23a and 23b; projectile 24 that flies downward from within cylinder 21a using the thrust generated by the combustion of igniter 22; and bus bar 25 that is configured by connecting conductor pieces 25a and 25c at both ends connected to current path 11 with central cutting portion 25b that is cut by projectile 24 that has gained the thrust. Furthermore, pyrotechnic fuses can instantaneously interrupt large currents in the event of an abnormality, compared to blowout fuses. Therefore, when power source 10 is a large-capacity, high-voltage battery installed in an EV (electric vehicle), current breaker 20 according to the present embodiment is preferably a pyrotechnic fuse.

[0014] The current detection unit 50 is a sensor that detects the current flowing through the current path 11, and is, for example, a shunt-type current sensor (a conductor piece having a low resistance, a shunt resistor). Note that the current detection unit 50 can use other types besides the shunt resistor (shunt type) (for example, a type that uses a non-contact current sensor such as a Hall element). However, in terms of ease of installation in the electrical circuit breaker 60, it is preferable to use a shunt resistor (shunt type), which can be made smaller than a current sensor that uses a Hall element.

[0015] The current conduction protection unit 30 is provided on two cables 44a and 44b that connect the circuit breaker control circuit 40 and the control terminals 23a and 23b of the current breaker 20 in a DC manner, and is a circuit that suppresses the breakdown current that flows from the control terminals 23a and 23b to the circuit breaker control circuit 40 via the two cables 44a and 44b after current is applied to the control terminals 23a and 23b.

[0016] Note that "two cables 44a and 44b connecting the circuit breaker control circuit 40 and the control terminals 23a and 23b of the current circuit breaker 20 in a DC manner" means that the control terminals 23a and 23b of the current circuit breaker 20 are connected in a DC manner to the circuit breaker control circuit 40, and that they are not insulated from each other via an isolation transformer or the like. In other words, in this embodiment, the current circuit breaker 20 performs a breaking operation by applying a current due to DC current flow from the circuit breaker control circuit 40.

[0017] In this embodiment, the current conduction protection unit 30 includes a common mode filter 31 provided on the paths of the two cables 44a and 44b, a first constant-voltage diode 32a connected between one of the two cables 44a and 44b (cable 44a) and a first constant-voltage power supply V1, and a second constant-voltage diode 32b connected between the other of the two cables 44a and 44b (cable 44b) and a second constant-voltage power supply V2. The first constant-voltage power supply V1 and the second constant-voltage power supply V2 may be the same as the reference power supply GND (e.g., 0 V) ​​of the circuit breaker control circuit 40, or may be power supplies that supply different potentials.

[0018] More specifically, the common mode filter 31 is composed of coils 31a and 31b, such as choke coils, connected to the paths of the two cables 44a and 44b, respectively. The first constant-voltage diode 32a is a constant-voltage diode for overvoltage protection, having an anode connected to the first constant-voltage power supply V1 and a cathode connected to the cable 44a. For example, it is a TVS (Transient Voltage Suppressor) diode or a Zener diode with a predetermined breakdown voltage (e.g., 24 V). The second constant-voltage diode 32b is a constant-voltage diode for overvoltage protection, having an anode connected to the second constant-voltage power supply V2 and a cathode connected to the cable 44b. For example, it is a TVS (Transient Voltage Suppressor) diode or a Zener diode with a predetermined breakdown voltage (e.g., 24 V). Although Figure 1 discloses two coils 31a and 31b that constitute the common mode filter 31, in this disclosure, the two coils 31a and 31b may be collectively referred to as "coil (singular)."

[0019] The circuit breaker control circuit 40 is a circuit that operates using the potential on the negative potential side of the power supply 10 as a reference potential, and is a control circuit that applies current to the control terminals 23a and 23b of the current breaker 20 via two cables 44a and 44b connected to the control terminals 23a and 23b based on a detection signal output from a current detection unit 50 that detects the current flowing through the current path 11, and is composed of an amplifier 41, a controller 42, and a drive circuit 43.

[0020] The amplifier 41 is an amplifier, for example a voltage amplifier circuit, that amplifies a signal corresponding to the current detected by the current detection unit 50 (here, a minute voltage corresponding to the voltage drop in the current detection unit 50) and outputs the amplified signal to the controller 42. The controller 42 is a circuit that controls the current breaker 20 to perform a break operation by outputting a control signal to the drive circuit 43 based on the signal output from the amplifier 41 (i.e., the voltage corresponding to the current detected by the current detection unit 50), and is configured, for example, by a microcomputer or the like having a memory for storing programs and the like, a timer, input / output ports, a processor for executing programs, and the like.

[0021] The drive circuit 43 applies a current for igniting the igniter 22 to the control terminals 23a and 23b of the current interrupter 20 via two cables 44a and 44b based on a control signal output from the controller 42. The drive circuit 43 includes a first transistor 43a having a first parasitic diode 43c connected between one of the two cables 44a and 44b (cable 44a) and a circuit power supply VDD (e.g., 5 V), and a second transistor 43b having a second parasitic diode 43d connected between the other of the two cables 44a and 44b (cable 44b) and a reference power supply GND. The first transistor 43a and the second transistor 43b are, for example, N-channel MOSFETs. The first parasitic diode 43c has an anode connected to the cable 44a and a cathode connected to the circuit power supply VDD (e.g., 0 V), and the second parasitic diode 43d has an anode connected to the cable 44b and a cathode connected to the cable 44b.

[0022] In the present embodiment, it is not essential that the first transistor 43 a and the second transistor 43 b have the first parasitic diode 43 c and the second parasitic diode 43 d, respectively. Therefore, the first transistor 43 a and the second transistor 43 b may be transistors without a parasitic diode, such as bipolar transistors.

[0023] In addition, the current conduction protection unit 30 and the circuit breaker control circuit 40 may be mounted on a single circuit board, or may be mounted on separate circuit boards, or the first constant voltage diode 32a and second constant voltage diode 32b that constitute the current conduction protection unit 30 and the drive circuit 43 may be mounted on a single circuit board.

[0024] Next, the operation of the electrical circuit breaker 60 according to this embodiment configured as described above will be described.

[0025] FIG. 2 is a flowchart showing the operation of the electrical circuit breaker 60 according to the embodiment.

[0026] First, the controller 42 of the circuit breaker control circuit 40 determines whether or not a predetermined current (e.g., an abnormal current corresponding to when the load 12 is short-circuited) has been detected by the current detection unit 50 based on the signal output from the amplifier 41 (S10).

[0027] As a result, if the specified current is not detected (No in S10), the controller 42 repeats the detection of the specified current, while if the specified current is detected (Yes in S10), it outputs a control signal to the drive circuit 43 so that the current required to ignite the igniter 22 is applied to the control terminals 23a and 23b of the current breaker 20 via the drive circuit 43 and two cables 44a and 44b (S11).

[0028] As a result, as shown in Fig. 3, in current breaker 20, igniter 22 is ignited, and projectile 24, propelled by the combustion of the gunpowder, flies downward from within cylinder 21a, colliding with cutting portion 25b of bus bar 25 and separating cutting portion 25b from bus bar 25, thereby cutting bus bar 25. Fig. 3 is a diagram showing the interruption operation of current breaker 20 provided in electrical circuit interruption device 60 according to the embodiment. More specifically, Fig. 3(a) shows a schematic cross-sectional view of current breaker 20 before the interruption operation, and Fig. 3(b) shows a schematic cross-sectional view of current breaker 20 after the interruption operation.

[0029] Now, suppose that, during an interruption by such a current breaker 20, an arc occurs within the current breaker 20 due to the disconnection of the bus bar 25, causing a high voltage to flow to the control terminals 23a and 23b of the current breaker 20, resulting in a breakdown current flowing from the control terminals 23a and 23b through the two cables 44a and 44b toward the circuit breaker control circuit 40. Even in such a case, in this embodiment, the current conduction protection unit 30 is provided on the path of the two cables 44a and 44b, so that the breakdown current flowing toward the circuit breaker control circuit 40 is suppressed, and the circuit breaker control circuit 40 is prevented from being destroyed.

[0030] More specifically, the breakdown current flowing from the control terminals 23a and 23b of the current breaker 20 to the breaker control circuit 40 via the two cables 44a and 44b is likely to become common mode noise that occurs substantially simultaneously in each of the two cables 44a and 44b, and can be suppressed by the common mode filter 31. Furthermore, when a high voltage generated in one of the two cables 44a and 44b (cable 44a) exceeds a first predetermined voltage determined by the voltage of the first constant-voltage power supply V1 and the breakdown voltage of the first constant-voltage diode 32a, a current flows through the first constant-voltage diode 32a toward the first constant-voltage power supply V1, thereby suppressing the voltage to the first predetermined voltage. Similarly, if the high voltage generated in the other of the two cables 44a and 44b (cable 44b) exceeds a second predetermined voltage determined by the voltage of the second constant-voltage power supply V2 and the breakdown voltage of the second constant-voltage diode 32b, the high voltage can be suppressed to the second predetermined voltage by a current flowing toward the second constant-voltage power supply V2 via the second constant-voltage diode 32b.

[0031] This prevents the breaker control circuit 40 from being destroyed by a high voltage sneaking in when the current breaker 20 operates.

[0032] Furthermore, the electric circuit interruption device 60 according to this embodiment is a type that operates the current breaker 20 by DC current flow rather than via an isolation transformer or the like, and includes the current conduction protection unit 30, which is a protection circuit realized by independent electronic components, so compared to a type that operates the current breaker 20 via an isolation transformer or the like, it is not necessary to independently execute the control process for "ignition" of the current breaker 20, the control process for "diagnosis," and the control process for "breakdown protection" of the breaker control circuit 40. Therefore, the electric circuit interruption device 60 according to this embodiment achieves high-speed interruption of the current breaker 20 and high detection accuracy with a simple circuit configuration.

[0033] 4 is a circuit diagram showing the configuration of an electrical circuit interruption device 60a according to a first modified example of the embodiment. This diagram mainly illustrates the differences from the electrical circuit interruption device 60 according to the above-described embodiment. The electrical circuit interruption device 60a according to this modified example includes a current conduction protection unit 30a that has a different specific configuration from the current conduction protection unit 30 included in the electrical circuit interruption device 60 according to the embodiment.

[0034] That is, the current conduction protection unit 30a according to this modification has a parasitic filter included in the two cables 44a and 44b that make up the twisted pair cable, instead of the common mode filter 31 in the embodiment. The parasitic filter is a parasitic common mode filter formed by inductor components included in the two cables 44a and 44b that make up the twisted pair cable, and a parasitic attenuator formed by resistance components, etc.

[0035] Furthermore, the current conduction protection unit 30a according to this modification only has the second constant-voltage diode 32b out of the first constant-voltage diode 32a and the second constant-voltage diode 32b according to the embodiment. The current conduction protection unit 30a according to this modification does not have the first constant-voltage diode 32a because the first parasitic diode 43c of the first transistor 43a of the drive circuit 43 performs the protection function of the first constant-voltage diode 32a according to the embodiment.

[0036] Here, in this modified example, the following has been found to be an example of a specific condition that reliably prevents the circuit breaker control circuit 40 from being destroyed by a high voltage sneaking in when the current breaker 20 operates.

[0037] (1) It is assumed that the withstand voltage of the first transistor 43a and the withstand voltage of the second transistor 43b are both greater than the breakdown voltage of the second constant voltage diode 32b.

[0038] (2) The second constant voltage diode 32b is not built into the same package as the first transistor 43a and the second transistor 43b, but is mounted on the same circuit board 45 as a separate component.

[0039] That is, the first transistor 43 a and the second transistor 43 b are contained in a first package, and the second voltage regulator diode 32 b is contained in a second package different from the first package. The first transistor 43 a, the second transistor 43 b, and the second voltage regulator diode 32 b are mounted on the same circuit board 45.

[0040] (3) The two cables 44a and 44b connecting the circuit board 45 and the control terminals 23a and 23b of the current breaker 20 are twisted pair cables with a length of 400 mm or more and 700 mm or less and a thickness of approximately 0.5 sq (AWG20) or less, and the number of twists in the twisted pair cable is 10 or more.

[0041] (4) The wiring distance A between the first transistor 43a and the second transistor 43b and the control terminals 23a and 23b of the current breaker 20 is set to be 20 times or more the wiring distance B between the first transistor 43a and the second transistor 43b and the second constant voltage diode 32b. Here, the wiring distance refers to the length of the current path (i.e., the wiring length or cable length).

[0042] In this way, in the electrical circuit breaker device 60a of this modified example, the two cables 44a and 44b are provided with a parasitic common mode filter, a first parasitic diode 43c, and a second constant voltage diode 32b, so that, as in the embodiment, when the current breaker 20 operates, the breaker control circuit 40 is prevented from being destroyed by high voltage leakage.

[0043] 5A is a circuit diagram showing the configuration of an electrical circuit interruption device 60b according to a second modified example of the embodiment. This diagram mainly illustrates the differences from the electrical circuit interruption device 60 according to the above-described embodiment. The electrical circuit interruption device 60b according to this modified example includes a current conduction protection unit 30b that has a different specific configuration from the current conduction protection unit 30 included in the electrical circuit interruption device 60 according to the embodiment.

[0044] That is, the current conduction protection unit 30b according to this modification has, instead of the common mode filter 31 according to the embodiment, two switch circuits 35a and 35b connected so as to be inserted into the paths of the two cables 44a and 44b, respectively, and a switch control circuit 36 ​​that detects a breakdown current flowing toward the circuit breaker control circuit 40 and turns off the two switch circuits 35a and 35b. The two switch circuits 35a and 35b and the switch control circuit 36 ​​may be mounted on the same circuit board as the circuit board on which the circuit breaker control circuit 40 is mounted, or may be mounted on a different circuit board.

[0045] The two switch circuits 35a and 35b are, for example, N-channel MOSFETs.

[0046] In this modification, the switch control circuit 36 ​​is a circuit for detecting a breakdown current, which turns off the two switch circuits 35a and 35b when the voltage in at least one of the two cables 44a and 44b is higher than a threshold value, and is composed of resistance elements 36a and 36c, an OR circuit 36b, a transistor 36d, and two photocouplers 36e and 36f. Note that the threshold value of the OR circuit is preferably higher than the voltage value required for diagnosis.

[0047] When a high voltage occurs in the cable 44b, the potential at the connection point between the cable 44b and the resistance element 36a exceeds the threshold value of the OR circuit 36b, causing the OR circuit 36b to output a High signal, which turns on the transistor 36d and lowers the potential at the connection point between the resistance element 36a and the transistor 36d, causing the two photocouplers 36e and 36f to output Low signals and turn off the two switch circuits 35a and 35b. In this way, when a high voltage occurs in the cable 44b, the two switch circuits 35a and 35b are turned off, and the breakdown current flowing from the control terminals 23a and 23b of the current breaker 20 to the circuit breaker control circuit 40 is interrupted.

[0048] As in the embodiment, the current conduction protection unit 30b according to this modification includes a first constant voltage diode 32a and a second constant voltage diode 32b.

[0049] In this modification, the resistor element 36a is connected to the cable 44b of the two cables 44a and 44b, but instead, the resistor element 36a may be connected to the cable 44a. Alternatively, a resistor element may be connected to each of the two cables 44a and 44b, and the higher of the voltages at their connection points may be input to the OR circuit 36b. As a result, when a high voltage is generated in the cable 44a or in either of the two cables 44a and 44b, the two switch circuits 35a and 35b are turned off.

[0050] Fig. 5B is a circuit diagram showing an example of the configuration of a current conduction protection unit 30c having another switch control circuit 37 instead of the switch control circuit 36 ​​shown in Fig. 5A. This diagram mainly illustrates the differences from the configuration of the switch control circuit 36 ​​shown in Fig. 5A.

[0051] The switch control circuit 37 shown in FIG. 5B is a circuit that detects a breakdown current and turns off two switch circuits 35a and 35b when the current flowing from at least one of the two cables 44a and 44b (cable 44b in this case) through at least one of the first constant-voltage diode 32a and the second constant-voltage diode 32b (the second constant-voltage diode 32b in this case) is higher than a threshold value.Instead of the resistance element 36a in FIG. 5A, the switch control circuit 37 has a resistance element 36g connected between the anode of the second constant-voltage diode 32b and the second constant-voltage power supply V2, and instead of the OR circuit 36b in FIG. 5A, an amplifier 36h.

[0052] When a high voltage occurs in the cable 44b, a current flows from the cable 44b to the second constant-voltage power supply V2 via the second constant-voltage diode 32b, and as a result, a potential difference occurs across the resistor element 36g. This potential difference is amplified by the amplifier 36h and output as a High signal to the transistor 36d. Thereafter, the two switch circuits 35a and 35b are turned off by the same operation as the switch control circuit 36 ​​in Fig. 5A. In this way, when a high voltage occurs in the cable 44b, the two switch circuits 35a and 35b are turned off, and the breakdown current flowing from the control terminals 23a and 23b of the current breaker 20 to the circuit breaker control circuit 40 is interrupted.

[0053] 5B , the resistor 36g is connected to the second regulating diode 32b of the first and second regulating diodes 32a and 32b. However, instead, the resistor 36g may be connected to the first regulating diode 32a. Alternatively, a resistor may be connected to each of the first and second regulating diodes 32a and 32b, and the higher of the potential differences across the resistors may be input to the amplifier 36h. As a result, when a high voltage is generated in the cable 44a or in either of the two cables 44a and 44b, the two switch circuits 35a and 35b are turned off.

[0054] In this way, in the electrical circuit interruption device 60b according to the second modified example shown in Figures 5A and 5B, the two cables 44a and 44b are provided with the two switch circuits 35a and 35b, the switch control circuits 36 and 37 that detect a breakdown current flowing toward the circuit breaker control circuit 40 and turn off the two switch circuits 35a and 35b, and the first constant voltage diode 32a and the second constant voltage diode 32b. Therefore, when the current interrupter 20 operates, the circuit breaker control circuit 40 is prevented from being destroyed by a high voltage leaking in.

[0055] As described above, the electrical circuit interruption device 60 etc. according to the present embodiment etc. is an interruption device that drives a current interrupter 20 having control terminals 23a and 23b that is provided on the current path 11, and is equipped with a circuit breaker control circuit 40 that applies current to the control terminals 23a and 23b via two cables 44a and 44b that are DC connected to the control terminals 23a and 23b based on a detection signal output from a current detection unit 50 that detects the current flowing through the current path 11, and a current conduction protection unit 30 that suppresses the breakdown current that flows from the control terminals 23a and 23b towards the circuit breaker control circuit 40 via the two cables 44a and 44b after applying the current to the control terminals 23a and 23b.

[0056] As a result, the current conduction protection unit 30 is provided between the current breaker 20 and the breaker control circuit 40, which prevents the breaker control circuit 40 from being destroyed by a sneak high voltage when the current breaker 20 operates. Furthermore, the electric circuit interruption device 60 or the like drives the current breaker 20 by DC current and includes the current conduction protection unit 30 independent of the breaker control circuit 40, so that high-speed interruption of the current breaker 20 can be achieved with a simpler circuit configuration than a type that operates the current breaker 20 via an isolation transformer or the like.

[0057] More specifically, the current conduction protection unit 30 includes a common mode filter 31 provided on the path of the two cables 44a and 44b, and at least one of a first constant-voltage diode 32a connected between one of the two cables 44a and 44b and the first constant-voltage power supply V1, and a second constant-voltage diode 32b connected between the other of the two cables 44a and 44b and the second constant-voltage power supply V2. As a result, the current conduction protection unit 30 is composed of two types of electronic components: the common mode filter 31, which is an electronic component independent of the circuit breaker control circuit 40, and at least one of the first constant-voltage diode 32a and the second constant-voltage diode 32b.

[0058] Here, the common mode filter 31 may be configured with coils 31a, 31b connected to the two cables 44a, 44b so as to be inserted in the paths of the two cables 44a, 44b. This makes it possible to suppress a common-phase breakdown current flowing from the current breaker 20 to the circuit breaker control circuit 40 when the current breaker 20 operates.

[0059] In the first modification of the embodiment, the two cables 44a and 44b are twisted pair cables, and the common mode filter 31 is realized by a parasitic filter formed by the twisted pair cables, thereby realizing the common mode filter 31 with a simpler configuration.

[0060] In the first modification of the embodiment, the breaker control circuit 40 includes a drive circuit 43 including a first transistor 43a having a first parasitic diode 43c connected between one of the two cables 44a and 44b and the circuit power supply VDD, and a second transistor 43b having a second parasitic diode 43d connected between the other of the two cables 44a and 44b and the reference power supply GND, and the current conduction protection unit 30 includes only the second constant-voltage diode 32b out of the first and second constant-voltage diodes 32a and 32b. Thus, a protection circuit that suppresses high voltages occurring in the two cables 44a and 44b is formed using a simple configuration including the first parasitic diode 43c of the first transistor 43a and the second constant-voltage diode 32b.

[0061] More specifically, the second constant voltage diode 32b is not built into the same package as the first transistor 43a and the second transistor 43b, but is mounted as a separate component on the same circuit board 45, and the wiring distance between the first transistor 43a and the second transistor 43b and the control terminals 23a and 23b may be 20 times or more the wiring distance between the first transistor 43a and the second transistor 43b and the second constant voltage diode 32b. This realizes an electrical circuit interruption device 60a with a simple configuration that can prevent the circuit breaker control circuit 40 from being destroyed by a sneak high voltage when the current interrupter 20 operates.

[0062] In the second modified example of the embodiment, the current conduction protection unit 30 includes two switch circuits 35a and 35b connected to the two cables 44a and 44b, respectively, so as to be inserted into the paths of the two cables 44a and 44b, a switch control circuit 36 ​​that detects a breakdown current flowing toward the circuit breaker control circuit 40 and turns off the two switch circuits 35a and 35b, and at least one of a first constant-voltage diode 32a connected between one of the two cables 44a and 44b and the first constant-voltage power supply V1 and a second constant-voltage diode 32b connected between the other of the two cables 44a and 44b and the second constant-voltage power supply V2. As a result, when the current breaker 20 operates, the current breaker 20 and the circuit breaker control circuit 40 are reliably interrupted by the two switch circuits 35a and 35b, and the breakdown current flowing from the current breaker 20 to the circuit breaker control circuit 40 can be reliably suppressed.

[0063] Here, the switch control circuit 36 ​​may include, as a circuit for detecting a breakdown current, a circuit that turns off the two switch circuits 35a and 35b when the voltage in at least one of the two cables 44a and 44b is higher than a threshold, or a circuit that turns off the two switch circuits 35a and 35b when the current flowing from at least one of the two cables 44a and 44b to at least one of the first voltage regulator diode 32a and the second voltage regulator diode 32b is higher than a threshold. In this way, the breakdown current flowing from the current breaker 20 to the breaker control circuit 40 can be suppressed by voltage detection or current detection, and the breaker control circuit 40 can be protected.

[0064] Furthermore, the current breaker 20 may be a pyro-fuse, which allows instantaneous interruption of a large current in the event of an abnormality, even if the power source 10 is a large-capacity, high-voltage battery mounted on an EV (electric vehicle).

[0065] While the electrical circuit interruption device according to the present disclosure has been described above based on the embodiments and modifications, the present disclosure is not limited to these embodiments and modifications. As long as they do not deviate from the gist of the present disclosure, various modifications that a person skilled in the art could conceive of to the present embodiments and modifications, and other forms constructed by combining some of the components of the embodiments and modifications, are also included within the scope of the present disclosure.

[0066] For example, a common mode filter formed of a coil such as a choke coil according to the embodiment may be provided as the common mode filter 31 provided on the path of the two cables 44a and 44b, and in addition, the two cables 44a and 44b may be configured as a twisted pair cable, as in the first modified example of the embodiment.

[0067] Furthermore, the embodiment, the first modification, and the second modification may be combined. For example, the current conduction protection unit may include the common mode filter 31 according to the embodiment, the two cables 44a and 44b constituting the twisted pair cable according to the first modification, and the switch circuits 35a and 35b according to the second modification. This realizes an electrical circuit interruption device that combines the features of the embodiment, the first modification, and the second modification and has an extremely high resistance to destruction of the control circuit against sneak high voltages.

[0068] Furthermore, when the reference potential of the circuit breaker control circuit 40 is set to the potential on the negative potential side of the power supply 10 , it may be the same as the negative potential of the power supply 10 or the negative potential of the load 12 .

[0069] The present disclosure can be used as an electrical circuit interruption device that drives a current breaker having a control terminal that is provided on a current path, for example, as an electrical circuit interruption device that drives a pyro-fuse that is provided on a current path that supplies current from a high-voltage battery to an inverter in an EV.

[0070] 10 Power supply 11 Current path 12 Load 20 Current breaker 21 Housing 21a Cylinder 22 Igniter 23a, 23b Control terminal 24 Projectile 25 Bus bar 25a, 25c Conductor piece 25b Cutting portion 30, 30a to 30c Current conduction protection portion 31 Common mode filter 31a, 31b Coil 32a First constant voltage diode 32b Second constant voltage diode 35a, 35b Switch circuit 36, 37 Switch control circuit 36a, 36c, 36g Resistance element 36b OR circuit 36d Transistor 36e, 36f Photocoupler 36h, 41 Amplifier 40 Breaker control circuit 42 Controller 43 Drive circuit 43a First transistor 43b Second transistor 43c First parasitic diode 43d Second parasitic diode 44a, 44b Cable 45 Circuit board 50 Current detection unit 60, 60a, 60b Electric circuit breaker VDD Circuit power supply GND Reference power supply V1 First constant voltage power supply V2 Second constant voltage power supply

Claims

1. An electric circuit interrupting device that is provided on a current path and drives a current breaker having a control terminal, comprising: a circuit breaker control circuit that applies current to the control terminal via two cables connected to the control terminal in a DC manner based on a detection signal output from a current detection unit that detects the current flowing through the current path; and a current conduction protection unit that suppresses a breakdown current that flows from the control terminal via the two cables toward the circuit breaker control circuit after applying current to the control terminal.

2. The electrical circuit interruption device according to claim 1, wherein the current conduction protection unit includes: a common mode filter provided on the path of the two cables; and at least one of a first constant-voltage diode connected between one of the two cables and a first constant-voltage power supply; and a second constant-voltage diode connected between the other of the two cables and a second constant-voltage power supply.

3. The electrical circuit interruption device according to claim 2, wherein the common mode filter is composed of a coil connected to the two cables so as to be inserted in the paths of the two cables.

4. The electrical circuit interruption device according to claim 2, wherein the two cables are twisted pair cables, and the common mode filter is a parasitic filter formed by the twisted pair cables.

5. The electrical circuit interrupting device according to claim 4, wherein the breaker control circuit has a drive circuit including a first transistor having a first parasitic diode connected between one of the two cables and a circuit power supply, and a second transistor having a second parasitic diode connected between the other of the two cables and a reference power supply, and the current conduction protection unit includes only the second constant voltage diode out of the first and second constant voltage diodes.

6. The electrical circuit interruption device according to claim 5, wherein the first transistor and the second transistor are housed in a first package, the second voltage regulating diode is housed in a second package different from the first package, the first transistor, the second transistor and the second voltage regulating diode are mounted on the same circuit board, and the wiring distance between the first transistor and the second transistor and the control terminal is 20 times or more the wiring distance between the first transistor and the second transistor and the second voltage regulating diode.

7. An electric circuit breaker according to any one of claims 1 to 6, wherein the current conduction protection unit includes: two switch circuits connected to each of the two cables so as to be inserted into the paths of the two cables; a switch control circuit that detects the breakdown current flowing toward the circuit breaker control circuit and turns off the two switch circuits; and at least one of a first constant-voltage diode connected between one of the two cables and a first constant-voltage power supply, and a second constant-voltage diode connected between the other of the two cables and a second constant-voltage power supply.

8. The electrical circuit interruption device according to claim 7, wherein the switch control circuit includes a circuit for detecting the breakdown current, the circuit turning off the two switch circuits when the voltage in at least one of the two cables is higher than a threshold value.

9. The electrical circuit interruption device according to claim 7, wherein the switch control circuit includes a circuit for detecting the breakdown current, the circuit turning off the two switch circuits when the current flowing from at least one of the two cables through at least one of the first constant voltage diode and the second constant voltage diode is higher than a threshold value.

10. An electrical circuit interrupting device according to any one of claims 1 to 9, wherein the current interrupter is a pyro-fuse.

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