JP5323550B2 - Vehicle power supply device - Google Patents

Description

  The present invention relates to a vehicular power supply device that supports various surge countermeasures and reverse power connection.

  2. Description of the Related Art Conventionally, a vehicle such as an automobile is supplied with power from an alternator and a battery (power source) to various electrical components and electronic components (loads) such as an ECU (Electric Control Unit). Appropriate measures are taken so that these loads are not damaged by a surge voltage generated by a load dump or the like.

  In vehicle maintenance, for example, an operator may mistakenly connect the power supply side terminal and the ground side terminal of the battery in reverse when replacing the battery. It is necessary to protect electrical components, ECUs, etc. from such reverse connection of the power supply. Even when the power supply side terminal and the ground side terminal are mistakenly connected reversely, wiring bodies such as loads and wires, and semiconductor switches, etc. Appropriate measures are taken to prevent damage.

  Specific measures against damage caused by a surge voltage generated in a load dump or the like can be realized by inserting a surge absorber such as a Zener diode (surge absorbing diode) in parallel at both ends of the load. Thereby, the surge voltage applied to both ends of the load can be clamped, and high voltage due to various surges is prevented from being applied. However, in a configuration in which a surge absorber is inserted in parallel at both ends of the load, a short circuit (short circuit) is formed via the surge absorber when the power supply is reversely connected, and a large current as in a dead short circuit is generated. There is a problem that the wiring body such as an electric wire is damaged.

  Specific measures for solving both the damage caused by the generation of a high voltage due to various surges and the damage caused by reverse connection of the power source include a protection method using a fuse and a protection method using a diode.

  FIG. 7 shows a protection method using a fuse. The power supply device 900 is connected to a power source 905 such as a battery, an IG switch, a switch 901, a fuse 902, and a load 906, and a Zener diode 903 is inserted at both ends of the load 906.

  In the protection method using the fuse in which the Zener diode 903 of FIG. 7 is inserted, even when an overvoltage occurs due to various surges, the surge voltage applied to both ends of the load 906 is clamped by the Zener diode 903. Is prevented from being applied with such a high voltage as to break. Thereby, damage to the load 906 can be prevented. Even when the power supply is reversely connected, the fuse 902 is melted by the reverse current that flows through the Zener diode 903, so that an excessive reverse current that burns the wiring body such as the wire is prevented from flowing, and the load 906 and the wire It is possible to prevent the wiring body from being damaged.

  FIG. 8 shows a protection method using a diode in which a Zener diode 912 is inserted. The power supply device 910 is arranged such that a diode 911 and a Zener diode 912 face each other between the power supply (+ B) and the ground, and power is supplied to the load 914 from between the diode 911 and the Zener diode 912 via the semiconductor switch 913. Supply.

  In the protection method using the diode of FIG. 8, even when an overvoltage occurs due to various surges, the surge voltage applied to both ends of the load 914 is clamped by the Zener diode 912, so that the load 914 can be prevented from being damaged. . Even when the power supply is reversely connected, the diode 911 prevents the current from flowing from the ground point to the power supply (+ B), so that the semiconductor switch 913, the load 914, and the wiring body such as an electric wire can be prevented from being damaged. Can do.

  In addition, as a protection method using a diode, in Patent Document 1, a diode and a surge absorbing element are connected to face each other to prevent a reverse current from flowing due to reverse connection of the power source by the diode and a reverse current flowing from the load to the power source. The current is limited to an allowable level by the load resistance component. Moreover, the structure which prevents damage to a load is described by clamping the abnormal high voltage which generate | occur | produces with various surges with a surge absorption element.

  In recent years, from the viewpoint of improving the degree of freedom in vehicle design by making maintenance-free, and reducing the size and weight, computerization of the fuse function (semiconductor) has been studied.

JP 2008-125191 A

  However, in the protection method using the fuse of FIG. 7, a large-capacity Zener diode 903 is required to protect the load 906 and the wiring body such as an electric wire by fusing the fuse 902 when the power supply is reversely connected. For this reason, a large-capacity component must be used for the Zener diode 903, and the Zener diode 903 becomes large, making it difficult to reduce the size of the device. Further, since it is necessary to use a large-capacity Zener diode 903, there is a problem that the leakage current increases, and the dark current of the vehicle increases. Furthermore, when the fuse 902 is used, the fuse blows when the power supply is reversely connected. Therefore, in consideration of maintainability, the fuse must be arranged so that it can be replaced. There is also a problem that it is difficult to improve the vehicle design freedom.

  In the protection method using the diode of FIG. 8, since it is necessary to flow a current to be supplied to the load 914 in a steady state, a large-capacity diode 911 is required. For this reason, the diode 911 must be large in size, and it is difficult to reduce the size of the device. Further, by inserting the diode 911 between the power supply (+ B) and the load 914, a voltage drop of VF (about 0.7V) due to the diode occurs. For this reason, since the voltage applied to the load 914 is lowered, there is a problem that the load cannot be normally operated when the voltage of the power supply is lowered.

  Moreover, in patent document 1, the voltage of the voltage drop VF of a diode was added to the clamp voltage by a surge absorption element, and there existed a problem that the voltage applied to load became high. When the voltage applied to the load becomes high, it is necessary to use a high-voltage component, and there is a problem of increasing the size and cost of the device.

  Therefore, the present invention has been made to solve these problems. Since no fuse is used, it is not necessary to use a large-capacity Zener diode, and it is possible to reduce the size of the apparatus. In addition, dark current can be reduced, and current consumption can be kept low. Furthermore, since no fuse is used, it is possible to contribute to an improvement in the degree of freedom in vehicle design by making maintenance free.

In addition, since it is not necessary to supply a current to the diode in power supply in a steady state, it is not necessary to use a large-capacity diode, and the apparatus can be downsized. In addition, it is possible to solve the problem that the voltage applied to the load increases when a surge occurs.

An aspect of the vehicle power supply device of the present invention includes: a semiconductor switch that supplies or stops power to a load; a voltage clamp element that is connected at one end between the semiconductor switch and the load and clamps a voltage; An overcurrent protection element that is connected in series with the voltage clamp element, interrupts current due to overcurrent, and is connected to the semiconductor switch to control and drive the semiconductor switch based on an external signal, and to ground A control unit having a terminal and a control signal input terminal to which the signal is input, one end connected between the voltage clamp element and the overcurrent protection element, and the other end connected to the control signal input terminal and the outside And a rectifying element that is connected so as to prevent a current flow from the other end to the one end, and the ground terminal is an overcurrent protection element. Wherein an end different from the voltage clamping element connected to end, characterized in that connected to said overcurrent protection devices.

In another aspect of the vehicle power supply apparatus of the present invention, the load is grounded, and the control unit is connected to instruction information input means for inputting the signal through the control signal input terminal, and the instruction information input means Is grounded, and the overcurrent protection element is connected to a ground point at an end different from the end connected to the voltage clamp element .

In another aspect of the vehicle power supply device of the present invention, the control information input means is a switch for inputting a control information signal for supplying or stopping the power supply to the load to the control unit, or a dead signal. It is a detector that detects occurrence of a short circuit and inputs a control information signal for stopping power supply to the load to the control unit .

In another aspect of the vehicle power supply device of the present invention, the semiconductor switch, the voltage clamp element, the overcurrent protection element, the control unit, the rectifier element, and the control information input means are accommodated in a junction box. characterized in that was.

  In another aspect of the vehicle power supply apparatus of the present invention, the overcurrent protection element is a PTC element.

  According to the first, second, and third aspects of the invention, it is not a protection method using a fuse or a protection method using a diode. The body can be protected, and further downsizing and low power consumption of the device can be realized.

  According to the fourth aspect of the present invention, it is possible to protect the semiconductor switch and the load even when various surges are generated and when the power supply is reversely connected, and further, the control unit that controls the semiconductor switch floats from the grounding point. It is possible to avoid the malfunction of the semiconductor switch due to the malfunction of the control unit.

1 is a schematic configuration diagram of a vehicle power supply device according to a first embodiment of the present invention. It is a schematic block diagram of the vehicle power supply device which concerns on 2nd embodiment of this invention. It is a schematic block diagram of the vehicle power supply device which concerns on 3rd embodiment of this invention. It is a schematic block diagram of the vehicle power supply device which concerns on 4th embodiment of this invention. It is a schematic block diagram of the vehicle power supply device explaining the operation of the fourth embodiment of the present invention. It is a schematic block diagram of the vehicle power supply device explaining the operation of the fourth embodiment of the present invention. It is a schematic block diagram of the conventional vehicle power supply device using a fuse. It is a schematic block diagram of the conventional vehicle power supply device using a diode.

  A configuration of a vehicle power supply device according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

  A vehicle power supply device according to a first embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic configuration diagram of a vehicle power supply device 100.

  As shown in FIG. 1, power is supplied to a load 20 from a power source (+ B) such as a battery via a junction box 1 (hereinafter referred to as J / B) in which a semiconductor switch 4 and the like are accommodated. Connection connectors 1a to 1d are provided in J / B1, and the connection connectors 1a to 1d are connected to the respective electronic components. The semiconductor switch 4 can be a field effect transistor (FET) or the like.

  The load 20 is an element having a resistance component such as a lamp. The reverse current flowing from the load 20 side to the power supply (+ B) side when the power supply is reversely connected is limited by the resistance component of the load 20. Moreover, the place where the load 20 is arranged is arranged at a place away from J / B1, and the grounding point 30 and the grounding point 31 are different places.

J / B 1 is mainly composed of a semiconductor switch 4 that supplies power to the load 20 and a control unit 5 that controls and drives the semiconductor switch 4.
The controller 5 has at least four terminals: a power input terminal 5a, a semiconductor switch control terminal 5b, a ground terminal 5c, and a control signal input terminal 5d. The power input terminal 5a is connected to a power source (+ B) and supplies power to the control unit 5 via the power input terminal 5a. Further, a rectifying element 7 is inserted between the power source (+ B) and the power source input terminal 5a so that no current flows from the power source input terminal 5a to the power source (+ B). The semiconductor switch control terminal 5b is connected to the semiconductor switch 4, and controls and drives the semiconductor switch 4 based on an external signal. The ground terminal 5c is connected to a ground point, the control signal input terminal 5d is connected to the signal input terminal 6 via the signal input line 10, and the control information (signal from the outside) of the semiconductor switch 4 is input. .

  The control information (signal from the outside) of the semiconductor switch 4 may be power ON / OFF instruction information by a combination switch provided around the handle, power OFF instruction information when a dead short occurs due to disconnection or the like. . The instruction information when a dead short occurs is detected by a detector (not shown). The detector (not shown) may be arranged in J / B1, or may be arranged outside J / B1.

  When instruction information from the combination switch is input or it is detected that a dead short has occurred, control information for stopping the power supply to the load 20 is input to the signal input terminal 6. And it inputs into the control part 5 via the signal input line 10 and the control signal input terminal 5d. The control unit 5 outputs a control signal from the semiconductor switch control terminal 5 b toward the semiconductor switch 4 in order to operate the semiconductor switch 4.

  In general, when power is supplied to the load by the semiconductor switch 4, a LOW signal (for example, a ground potential) is input to the control signal input terminal 5d. The electrical condition of the LOW signal varies depending on the input condition of the control unit 5. After the LOW signal is input to the control signal input terminal 5d, a voltage higher than the power supply (+ B) is output from the semiconductor switch control terminal 5b, and the semiconductor switch 4 is controlled to be in a conductive state (ON state). Power is supplied to the load.

  Between the power source (+ B) and the ground point 32, a voltage clamp element 2 and an overcurrent protection element 3 that clamp both ends of the load 20 with a certain voltage are arranged in series. The voltage clamp element 2 can be a Zener diode or the like, and the overcurrent protection element 3 can be a PTC (Positive Temperature Coefficient) element whose resistance value increases as the temperature rises. In FIG. 1, the voltage clamp element 2 is arranged on the power supply (+ B) side and the overcurrent protection element 3 is arranged on the ground point 32 side, but the overcurrent protection element 3 is arranged on the power supply (+ B) side. It is also possible to arrange the voltage clamp element 2 on the ground point 32 side.

  Thus, by arranging the voltage clamp element 2 and the overcurrent protection element 3 in series between the power source (+ B) and the ground point 32, even when various surges occur, the voltage clamp element 2 can connect both ends of the load 20. By clamping the voltage, it is possible to prevent an excessive voltage from being applied to the load 20. Even when the power supply is reversely connected, the overcurrent protection element 3 generates heat due to the instantaneous flow of current to the voltage clamp element 2 and the resistance increases, so that the current flowing from the ground point 32 to the power supply (+ B) side is reduced. It becomes possible to suppress. Further, since the current flowing from the ground point 30 to the power supply (+ B) side is limited by the resistance component of the load, it is possible to suppress a large reverse current that occurs at the time of dead short. Thus, even when the power source is reversely connected, the protection of the wiring body such as an electric wire can be realized. The reverse current flowing from the ground point 31 to the power supply (+ B) side can be blocked by the rectifying element 7.

  In addition, when a reverse current whose current is limited flows from the ground point 30 to the power source (+ B) side, the semiconductor switch 4 is in a conductive state (ON state) related to control information (signal from the outside) from the signal input terminal 6. ) This is because the semiconductor switch 4 is generally composed of an N-channel FET, and the operation of the N-channel FET is determined by the relationship between the voltage of the semiconductor switch control terminal 5b and the voltage of the connection connector 1b. is there. This is because the voltage of the semiconductor switch control terminal 5b is larger than the voltage of the connection connector 1b by the voltage drop of the load 20 when the power supply is reversely connected. Even when the current semiconductor switch 4 is in a conductive state, the current of the reverse current is limited, so that the heat generation of the current semiconductor switch 4 is suppressed and is not broken.

  As described above, since the present invention is a protection method that does not use a fuse, it is possible to suppress an increase in the size of a device and an increase in power consumption that are problematic when a fuse is used. Furthermore, since there is no fuse, maintenance-free operation is possible, and it is not necessary to design the vehicle in consideration of replacement work. Therefore, simplification of harness routing work and reduction of harness weight can be realized. In addition, when the diode is used, it is possible to suppress an increase in the size of the device due to the current flowing through the diode in a steady state, and the clamp voltage increases by using a PTC element for the overcurrent protection element 3. This problem can also be solved.

  Note that the ground point 32 where the voltage clamp element 2 and the overcurrent protection element 3 are grounded and the ground point 31 where J / B1 is grounded are in different locations, but there is a voltage in J / B1. It is also possible to mount the clamp element 2 and the overcurrent protection element 3 and share the ground points 31 and 32. In this way, vehicle design such as arrangement of electronic parts such as J / B1 and securing of a grounding point is facilitated, and harness wiring work can be simplified and harnesses can be reduced.

  Next, a vehicle power supply device according to a second embodiment of the present invention will be described below with reference to FIG. FIG. 2 is a schematic configuration diagram of the vehicle power supply device 200.

  2 is mainly for the purpose of protecting the inductive surge. The difference from FIG. 1 is that the voltage clamp element 2 and the overcurrent protection element 3 are connected to the semiconductor switch 4 and the L load 21. It is connected to the ground line 30 and the ground point 30, and is arranged in parallel with the L load 21. Normally, the voltage clamp element 2 is arranged in parallel with the L load 21 for the inductive surge in the L load 21 such as a motor, but the overcurrent protection element 3 is connected to the voltage clamp element 2 in addition to the voltage clamp element 2. They are arranged in series. In FIG. 2, the voltage clamp element 2 is disposed on the semiconductor switch 4 side and the overcurrent protection element 3 is disposed on the ground point 30 side. However, the overcurrent protection element 3 is disposed on the semiconductor switch 4 side. It is also possible to arrange the voltage clamp element 2 on the ground point 30 side.

  Thus, by connecting the voltage clamp element 2 and the overcurrent protection element 3 to the wiring connecting the semiconductor switch 4 and the L load 21 and the ground point 30, both ends of the L load 21 are connected by the voltage clamp element 2. It is possible to prevent an excessive voltage due to an inductive surge applied to the L load 21 from being applied. Even when the power supply is reversely connected, the overcurrent protection element 3 generates heat and increases resistance due to the instantaneous flow of current, so that the current flowing from the ground point 30 to the power supply (+ B) side can be suppressed. Thus, protection of the wiring body such as an electric wire connecting the voltage clamp element 2 and the overcurrent protection element 3 can be realized. As in FIG. 1, the current flowing from the ground point 30 to the power source (+ B) via the L load 21 is limited by the L load 21, so that a large reverse current generated at the time of a dead short can be suppressed. Thus, the semiconductor switch 4 and the wiring body such as an electric wire can be protected.

  Next, a vehicle power supply device according to a third embodiment of the present invention will be described below with reference to FIG. FIG. 3 is a schematic configuration diagram of the vehicle power supply device 300.

  In FIG. 3, the voltage clamp element 2 and the overcurrent protection element 3 are arranged in series between the power source (+ B) and the ground point 31 as shown in FIG. 1, and further the voltage clamp for the inductive surge protection of FIG. The element 2 and the overcurrent protection element 3 are connected to the ground point 30 and the wiring connecting the semiconductor switch 4 and the L load 21 so as to be in parallel with the L load 21. 1 and 2, the arrangement of the voltage clamp element 2 and the overcurrent holding element 3 can be reversed.

  With such a configuration, even when various surges occur in the semiconductor switch 4, the load 20, and the L load 21, the voltage is clamped by the voltage clamp element 2, so that the load 20 and the L load 21 are excessively large. In addition to preventing voltage from being applied, and even when the power supply is reversely connected, the overcurrent protection element 3 generates heat and increases resistance due to instantaneous current flow, so that the power supply (+ B) side from the ground points 30 and 31 increases. It is possible to suppress the current flowing through the semiconductor switch 4 and protect the semiconductor switch 4 and the wiring body such as an electric wire.

  In FIG. 3, a plurality of semiconductor switches 4 are controlled and driven by a single control unit 5, but it is also possible to prepare a control unit 5 for each of the plurality of semiconductor switches 4 and drive them separately. Also, by mounting all the voltage clamp elements 2 and the overcurrent protection elements 3 in J / B1, it is possible to have only one ground point.

Next, a vehicle power supply device according to a fourth embodiment of the present invention will be described below with reference to FIGS.
FIG. 4 is a schematic configuration diagram of the vehicle power supply device 400. 5 is a schematic configuration diagram when the grounding point 31 connected to J / B1 of the vehicle power supply device 400 is removed, and FIG. 6 is connected to J / B1 of the vehicle power supply device 400. FIG. 6 is a schematic configuration diagram when the grounding point 31 that has been disconnected is removed and the switch 22 is turned on (ON state).

  In FIG. 4, the ground line 11, the bypass line 12, and the rectifying element 7 inserted into the bypass line 12 are mainly added to the power supply apparatus 200 of FIG. 2, and the signal input terminal 6 in the signal input line 10 is added. Is connected to the ground point 40 via the switch 22. The voltage clamp element 2 and the overcurrent protection element 3 are mounted on J / B 1, and the overcurrent protection element 3 is connected to the ground point 31.

  By setting the switch 22 to the conductive state (ON state) / non-conductive state (OFF state), the operation of the semiconductor switch 4 is instructed. When the switch 22 is turned on, a LOW signal is input to the control signal input terminal 5d, and power is supplied to the L load 21 by the semiconductor switch 4. Further, when the switch 22 is turned off, the power supply to the L load 21 by the semiconductor switch 4 is stopped. This switch 22 is controlled by the above-described combination switch or instruction information from a detector that detects a dead short or the like. Note that when the electrical condition is set so that the power is supplied to the load when the High signal is input to the signal input terminal 6 when the input condition of the control unit 5 is input to the control unit 5. In either case, it is possible to cope with this problem by inserting an inverter that inverts the signal.

  The ground line 11 is connected to a wiring between the ground terminal 5 c of the control unit 5, the overcurrent protection element 3, and the ground point 31. The bypass line 12 is connected to a wiring (connection point 8) for connecting the voltage clamp element 2 and the overcurrent protection element 3 and the signal input line 10. The rectifying element 7 is inserted into the bypass line 12 so as to prevent the flow of current from the signal input line 10 to the connection point 8.

  With the configuration of FIG. 4, it is possible to prevent damage to the semiconductor switch 4, the load 21, and the wiring body such as electric wires even when various surges occur or when the power supply is reversely connected, and the grounding point 31 is J / B 1. Even when the control unit 5 that controls and drives the semiconductor switch 4 is lifted from the ground point 31, it is possible to prevent malfunction of the semiconductor switch 4 due to malfunction of the control unit 5.

  A method for preventing malfunction of the semiconductor switch 4 due to malfunction of the control unit 5 even when the control unit 5 floats from the ground point 31 will be described in detail below with reference to FIGS.

  Usually, J / B1 is connected to the ground point 31 via the connection connector 1d. The connection connector 1d may come off due to vibration or the like, and J / B1 may be in an electrically floating state. In this case, there is a problem that the control state of the control unit 5 becomes very unstable. Therefore, in addition to the ground point 31, J / B 1 is provided with another ground point (not shown) as a spare, so that even when the ground point 31 is disconnected, the ground state is secured by another ground point. It was like that.

  However, in this case, a spare grounding point must be provided separately, and there are problems of securing a mounting location, increasing the number of harnesses for connection, and labor during manufacturing.

  FIG. 5 shows a state in which the ground point 31 has deviated from J / B1 in the power supply apparatus 400 of FIG. Further, the switch 22 that controls the semiconductor switch 4 is in a non-conductive state, and the supply of power to the L load 21 is stopped.

  Normally, when the ground point is removed, the ground terminal 5c of the control unit 5 is in a state of being electrically floated and the semiconductor switch 4 may malfunction, but in FIG. 5, the ground terminal 5c is an overcurrent protection element. 3. Since it is connected to the ground point 30 via the voltage clamp element 2 and the L load 21, the ground terminal 5c is close to a state where it is connected to the ground terminal. For this reason, the control unit 5 does not float electrically. In the present embodiment, the case where the load is the L load 21 has been described. However, the control unit 5 does not float electrically even in the load 20.

  Next, FIG. 6 shows a state where the ground contact point 31 has deviated from J / B1, as in FIG. The switch 22 that controls the semiconductor switch 4 is in a conductive state, and power is supplied to the L load 21.

  In this case, since the ground terminal 5c is connected to the ground point 40 via the rectifying element 7 and the switch 22 via the overcurrent protection element 3 and the connection point 8, the ground terminal 5c is connected to the ground terminal. It becomes close to the state. For this reason, the control unit 5 does not float electrically.

  With the configuration shown in FIG. 4, the semiconductor switch and the load can be protected even when various surges occur and when the power supply is reversely connected, and further, another grounding point through a new harnel is increased. Therefore, it is possible to avoid the problem that the control unit 5 is electrically floated regardless of the supply state of power to the load, and it is possible to prevent malfunction of the semiconductor switch 4 due to malfunction of the control unit 5. It becomes. Although not shown in FIGS. 4 to 6, the control unit 5 can be controlled by the switch 22 related to the state of the ground point 31 by pulling up the signal input line 10.

100, 200, 300, 400 Vehicle power supply device 1 Junction box (J / B)
2 Voltage clamp element 3 Overcurrent protection element 4 Semiconductor switch 5 Control unit 6 Signal input terminal 7 Rectifier element 8 Connection point 10 Signal input line 11 Ground line 12 Bypass line 20 Load 21 L load 22 Switch 30, 31, 32, 40 connection Point 900, 910 Power supply device 901 Switch 902 Fuse 903, 912 Zener diode 905 Power source 906, 914 Load 911 Diode 913 Semiconductor switch

Claims (5)

A semiconductor switch for supplying or stopping power supply to the load;
A voltage clamping element, one end of which is connected between the semiconductor switch and the load, and clamps a voltage;
An overcurrent protection element connected in series with the voltage clamp element to cut off a current due to an overcurrent;
A control unit connected to the semiconductor switch to control and drive the semiconductor switch based on an external signal; and a control terminal having a ground terminal and a control signal input terminal to which the signal is input;
One end is connected between the voltage clamp element and the overcurrent protection element, the other end is connected between the control signal input terminal and the outside, and the current from the other end to the one end A rectifying element connected to prevent the flow of
With
The ground power terminal is connected to the overcurrent protection element at an end different from an end connected to the voltage clamp element of the overcurrent protection element . The load is grounded, the control unit is connected to instruction information input means for inputting the signal by the control signal input terminal, the instruction information input means is grounded, and the overcurrent protection element is the voltage The vehicle power supply device according to claim 1, wherein the vehicle power supply device is connected to a ground point at an end different from the end connected to the clamp element . The control information input means is a switch that inputs a control information signal for supplying or stopping the power supply to the load to the control unit, or a power supply to the load by detecting the occurrence of a dead short The vehicle power supply device according to claim 2 , wherein the vehicle power supply device is a detector that inputs a control information signal for stopping the operation to the control unit. The vehicle switch according to claim 2 , wherein the semiconductor switch, the voltage clamp element, the overcurrent protection element, the control unit, the rectifier element, and the control information input means are accommodated in a junction box. Power supply device.   The vehicular power supply device according to any one of claims 1 to 4, wherein the overcurrent protection element is a PTC element.

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