JP2001078350A - Layer short circuit detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a layer short circuit detector that can control a circuit to on/off conditions, depending on the operations of an external switch for the on/off control of an electrical load for the circuit, in which the layer short circuit detector is provided. SOLUTION: This layer short circuit detector is provided as an internal structure with a current sensor 13 for detecting a current flowing into an electrical circuit for automobile, a determining unit 16 for determining as to whether the current detected with a current sensor 13 is in the layer short circuit condition and a FET 14 for cutting off the electrical circuit when the determining unit 16 determines the layer short circuit condition. The determining unit 16 can be connected with an external switch 30 for turning on/off the supply of current for a load 29 of the electrical circuit to determine the ON/OFF condition of the external switch 30 and then turns on/off the FET 14, based on the result of the determination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly detects an overcurrent flowing in an electric circuit for an automobile, particularly an intermittent short circuit which cannot be protected by a conventional blade type fuse, and shuts off the circuit to protect an electric wire. It relates to a rare short detector that enables it.

[0002]

2. Description of the Related Art A conventional fuse mounted in a fuse box for an automobile is disclosed in US Pat.
There is a blade type fuse of the type disclosed in Japanese Patent No. 023264. Many of the conventional blade type fuses are used in electric systems of automobiles, and have a function of protecting a circuit by melting a fusing portion by Joule heat in a case of a dead short in which a large current flows continuously.

For this reason, the fuse is blown at the time of a dead short in which a large current continuously flows, but the fuse may not be blown in a short intermittent rare short region. If a rare short circuit occurs in the circuit, the blade type fuse may not blow and the electric wire may smoke or ignite, causing a vehicle fire.

The applicant of the present application has proposed a fuse having a rare short judging function capable of judging a rare short as described in Japanese Patent Application No. Hei 10
-90866 and Japanese Patent Application No. 10-255204.

[0005]

As described above, in the conventional fuse, the fusing portion is melted by Joule heat to protect the circuit. In the case of an intermittent short circuit, the temperature may not rise to the melting temperature, and the fuse may not be blown, and the rare short circuit may not be protected.

Further, the fuse with a rare short judging function filed by the present inventor has made it possible to reliably detect and judge a rare short. However, it opens and closes a circuit and a component for judging a rare short. Parts are separate. Therefore, to protect the circuit, a rare short is detected,
Since it is necessary to interrupt the circuit, a rare short is detected,
A circuit is needed to connect the determined component to the part that opens and closes the circuit. From the above, the circuit becomes complicated and very expensive.

An object of the present invention is to provide a rare short detector capable of simplifying a circuit configuration and reducing costs.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, an invention according to claim 1 is a rare short detector installed between a power supply and an electric load in an electric circuit for a vehicle, Detecting means for detecting the current flowing in the circuit, determining means for determining whether the current detected by the detecting means is a rare short circuit, and when the determining means determines that there is an abnormality, the electric circuit The interruption means for interrupting is internally configured, and the determination means is connectable to an external switch circuit for turning on and off the current supply to the electric load of the electric circuit, and judges whether the external switch circuit is on or off, The gist of the invention is a rare short detector that turns on and off the blocking means based on the determination result.

In a second aspect of the present invention, in the first aspect, the detecting means is a rare short detector which is a fuse. According to a third aspect of the present invention, in the first aspect, the interruption means includes a rare short detector that is a semiconductor relay.

According to a fourth aspect of the present invention, in the first aspect, the detecting means, the judging means, and the interrupting means, which are internally configured, are based on a rare short detection that is integrally packaged.

According to a fifth aspect of the present invention, in the first aspect, the detecting means is provided corresponding to a plurality of circuits provided for each of a plurality of electric loads, and the judging means comprises: A single detecting means or a plurality of determining means for determining whether or not the current detected by the circuit corresponding to the means is a rare short circuit, wherein the interrupting means corresponds to each of the circuits, or Each circuit is provided in a branched main circuit, and when the determination means corresponding to the single or each circuit determines an abnormality, the corresponding electric circuit is cut off, Alternatively, the plurality of judging means judges whether an external switch circuit for turning on / off a current supply to an electric load of an electric circuit provided for each of the plurality of circuits is turned on / off, and based on the judgment result, the main circuit of Alternatively, the corresponding short circuit detector for turning on and off the blocking means of the circuit in which the gist.

(Operation) In the first aspect of the present invention, the detecting means detects the current flowing through the circuit, and the determining means determines whether or not the current detected by the detecting means is a rare short. The interrupting unit interrupts the electric circuit when the determining unit determines that the electric circuit is abnormal.

The judging means judges whether an external switch circuit for turning on / off the current supply to the electric load of the electric circuit is turned on / off, and turns on / off the cutoff means based on the judgment result.

According to the second aspect of the present invention, the operation of the first aspect of the present invention is realized by using the fuse as the detecting means. According to the third aspect of the present invention, the function of the first aspect of the present invention is realized by using a semiconductor relay as the shutoff means.

According to the fourth aspect of the present invention, since the detecting means, the judging means, and the interrupting means which are internally configured are packaged integrally, it is possible to easily arrange them in the circuit.

In the invention of claim 5, the single judging means or the plural judging means judges whether or not the current detected by the circuit corresponding to each detecting means is a rare short. or,
The shutoff means cuts off the corresponding electric circuit when the single or corresponding judgment means judges that each circuit is abnormal.

The single or plural judging means judges on / off of an external switch circuit for turning on / off current supply to an electric load of an electric circuit provided corresponding to each of the plural circuits, and based on the judgment result. To turn on / off the shutoff means of the main circuit or the corresponding circuit.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment of a rare short detector F according to the present invention will be described below with reference to FIGS.

FIG. 1 is an electric circuit diagram for a vehicle including the rare short detector F, and FIG. 2 is a perspective view of an example of the rare short detector F. As shown in FIG. 2, the rare short detector F includes a conductive terminal 11, a signal input terminal 12, and a detecting unit 1.
3. Power MOSFET (hereinafter simply referred to as FET) 1
4. The output terminal 15, the judging unit 16, the relay electrode 18, and the like are molded and packaged with a molding material 17 such as an epoxy resin, and the whole is formed in a flat hexagonal shape.

The conductive terminal 11 is formed in a flat plate shape on one side surface of the package, and an inner surface of the conductive terminal 11 is coated with an insulating film (not shown), and a determining unit 16 as a determining means is mounted and fixed. Have been. The lower surface (in FIG. 2) of the conductive terminal 11 is exposed by peeling off the insulating film.

An L-shaped branch piece 11 is connected to the conductive terminal 11.
A thin detecting portion 13 corresponding to the current carrying capacity of the fuse is integrally connected between the branch piece 11a and the relay electrode 18 disposed opposite to the branch piece 11a.

The output terminal 15 has an outer end protruding outward in an L-shape on one side surface of the package.
A power MOSFET (hereinafter simply referred to as an FET) 14 as a shut-off means, a relay, and a semiconductor relay is mounted and fixed on the inner surface of the inner end of 5.

The drain (not shown) of the FET 14 is electrically connected to a relay electrode 18 via a conductive bar 19, and the source (not shown) is connected to the output terminal 1.
5 is electrically connected. Further, the gate of the FET 14 is electrically connected to a relay control terminal 20 (see FIG. 1) of the determination unit 16.

The pair of input terminals 22 and 23 of the judging section 16 shown in FIG. 1 are connected to the conductive terminal 11 and the relay electrode 18 connected to both ends of the detecting section 13 via lead wires 24 and 25 shown in FIG. Have been. The ground terminal 27 of the judging section 16 has an outer end protruding outward in an L-shape on one side surface of the package similarly to the output terminal 15, and the inner end is electrically connected via a lead wire 26. Have been.

The rare short detector F is mounted on a terminal block (not shown) provided in an electric circuit for an automobile. In the case of this circuit, the judgment unit 16 or
If any one of the FETs 14 does not operate normally, the detection unit 13 of the rare short detector F is blown and the circuit is cut off at the time of a normal short dead time in which a large current flows continuously. The load 29 includes, for example, a headlamp, a radio, and the like (not shown).

The current flowing through the rare short detector F is applied to the conductive terminal 11, the output terminal 15, and the input terminal 2.
Signals (voltages) are always input (applied) to the determination unit 16 via 2 and 23.

Here, the detecting section 13 constitutes detecting means and a resistance element. Hereinafter, the detecting section 13 is referred to as a current sensor 13. As shown in FIG.
The external terminal connecting portion protrudes from the package on one side surface of the package like the output terminal 15, and the inner end is electrically connected to the external signal input terminal 28 of the determination section 16.

The signal input terminal 12 is adapted to be connected to an external switch 30 as an external switch circuit of a vehicle. When an ON signal is input and the external switch 30 is turned off, the determining unit 16
, A switch-off signal is input.

The judgment section 16 is composed of an IC 16A and a microcomputer 16B. The IC 16A compares whether or not the voltage (potential difference) across the current sensor 13 input through the input terminals 22 and 23 is equal to or higher than a threshold voltage for performing a rare short circuit determination, and outputs a comparison result to the microcomputer 16B. The voltage (potential difference) across the current sensor 13 is
It has a proportional relationship with the value of the current flowing through the current sensor 13, and the magnitude of the flowing current can be measured by detecting the voltage between both ends.

The microcomputer 16B includes a central processing unit (not shown), a ROM for storing a "rare short overcurrent protection control program" and an "energization / cutoff control program", and a working memory (RAM). And microcomputer 1
6B, in accordance with the "rare short overcurrent protection control program", determines whether or not the comparison result of each time of the IC 16A exceeds the abnormal level stored in the ROM. For example, when the comparison result is an abnormal level, the abnormal level duration time is compared with the duration determination reference value stored in the ROM, or when the comparison result is the abnormal level, the abnormal level per predetermined time is determined. And a comparison between the number of times of passage and the reference value of the number of times of passage stored in the ROM.

For example, when the comparison result of the IC 16A is an abnormal level, the abnormal level continuation time and R
When the microcomputer 16B determines that the short circuit is a rare short as a result of the comparison determination with the continuation time determination reference value stored in the OM, the microcomputer 16B operates the relay control terminal 20 of the IC 16A.
And outputs a control signal to the gate of the FET 14 through the FE.
T14 is turned off (cut off).

Alternatively, as a result of comparing the number of passes of the abnormal level per predetermined time when the comparison result of the IC 16A is an abnormal level with the reference value of the number of passes stored in the ROM, the microcomputer 16B determines that the short circuit is a rare short. Is determined, the microcomputer 16B outputs a control signal to the gate of the FET 14 via the relay control terminal 20 of the IC 16A,
The FET 14 is turned off (cut off).

When the microcomputer 16B receives a switch-on signal when the external switch 30 is turned on, the microcomputer 16B determines "energization" in accordance with the "energization / shutoff control program", and determines whether or not the relay control terminal 20 of the IC 16A. A control signal is output to the gate of the FET 14 via the
14 is turned on (conducting).

Further, when the microcomputer 16B receives a switch-off signal when the switch is turned off, the microcomputer 16B makes a judgment of "cut-off" according to the "energization / cut-off control program".
A control signal is output to the gate of the FET 14 via the relay control terminal 20 of the IC 16A, and the FET 14 is turned off (cut off).
I do.

In this embodiment, the IC 16A and the microcomputer 1
6B constitute a determination means and an output means.
Now, the rare short detector F configured as described above has the following features. (1) In the present embodiment, the rare short detector F
Current sensor 1 for detecting the current flowing in the electric circuit for automobile
3 (detecting means), a judging unit 16 (judging means) for judging whether the current detected by the current sensor 13 is a rare short, and when the judging unit 16 judges a rare short,
An FET 14 (interrupting means) for interrupting an electric circuit is provided as an internal configuration. The determining unit 16 can be connected to an external switch 30 (external switch circuit) for turning on and off the current supply to the load 29 of the electric circuit, determines whether the external switch 30 is on or off, and determines the FET 14 based on the determination result. Was turned on and off.

As a result, the current sensor 13 detects the current flowing in the electric circuit, and the determination unit 16 determines whether the current detected by the current sensor 13 is a rare short. The FET 14 turns off (cuts off) the electric circuit. Further, the determination unit 16 determines whether the external switch 30 is on or off, and based on the determination result, determines whether the FE is
Turn T14 on and off. As a result, the electric circuit for the vehicle can be turned on and off also by operating the external switch 30.

(2) In the present embodiment, the current sensor 13
(Detection means) was formed from a detection portion which was a fuse. As a result, in the case of this circuit, if a dead short circuit occurs between the rare short detector F and the load (electric load) 29 as shown in FIG. Even if at least one of them does not operate normally, the current sensor 13 is blown and the electric circuit can be cut off at the time of a dead short circuit in which a large current continuously flows normally.

(3) In this embodiment, the cutoff means is constituted by the FET 14 as a semiconductor relay. As a result, the configuration can be simplified as the switching element, and the size can be reduced when packaged as the rare short detector F.

(4) In this embodiment, in the rare short detector F, the current sensor 13, the FET 14, and the judging unit 16 are all integrated in a mold package. As a result, it is possible to provide a compact and inexpensive circuit protector that can detect a rare short circuit by using recent electronic technology while making it easy to use in an electric circuit for a vehicle.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG.
This will be described with reference to FIGS. FIG. 3 is an electric circuit diagram for a vehicle including the rare short detector F. FIG. 4A is a plan view of the rare short detector without the molding material.
(B) is a front view, and (c) is a right side view. FIG. 5 shows the right side of the rare short detector.

In the present embodiment, as shown in FIG. 4D, the multilayer insulating substrate 41 having a square plate shape has an outer surface (FIG. 4B).
A wide conductor pattern (hereinafter, referred to as a conductive terminal pattern) 42a is provided along the longitudinal direction at the center in the lateral direction on the lower surface in FIG. The conductive terminal pattern 42 is branched at three places, and each branch conductor portion 43 is formed on the inner surface of the multilayer insulating substrate 41 through a plated through hole (not shown) provided in the multilayer insulating substrate 41 (FIG. 4B).
(The upper surface).

One end of each of thin-walled first to third detectors 45a to 45c corresponding to the current carrying capacity of the fuse is integrally connected to each land 44. The first to third detectors 45a to 45c traverse over the concave portion 46 provided on the inner surface of the multilayer insulating substrate 41, and the other ends are integrally connected to other lands 47 provided on the inner surface of the multilayer insulating substrate 41. Have been. The first to third detection units 45a to 45c constitute detection means, a resistance element, and a current sensor.

Each of the lands 47 is provided with a disconnecting means via a connection lead 48 and a power MOS as a semiconductor relay.
The drains (not shown) of the first to third relays 49a to 49c composed of FETs are connected. The connection lead 48 is connected to the first to third detectors 45a to 45c.
It has a thicker shape with a larger current-carrying capacity.

The first to third relays 49a to 49c are fixed on the upper surfaces of the inner ends of the first to third conductive terminals 50a to 50c fixed on the inner surface of the multilayer insulating substrate 41.
Sources (not shown) are connected to the inner ends of the third to third conductive terminals 50a to 50c. The first to third conductive terminals 50a to 50c are arranged along the inner surface of the multilayer insulating substrate 41, and the outer end is bent along the side edge of the multilayer insulating substrate 41 into a crank shape. From the side.

The judging section 51 is fixed on a GND connection terminal 55 fixed on the inner surface of the multilayer insulating substrate 41.
Are grounded via the GND connection terminal 55. The GND connection terminal 55 is arranged along the inner surface of the multilayer insulating substrate 41, is bent in a crank shape along the side end of the multilayer insulating substrate 41, and protrudes laterally from the side end.

Each of the lands 44 is connected to each wiring pattern provided in the inner intermediate layer of the multilayer insulating substrate 41 through a plated through hole (not shown), and each of the wiring patterns is a plated through hole (not shown). Are connected to the respective wiring patterns on the inner surface of the multilayer insulating substrate 41 via. Each wiring pattern on the inner surface of the multilayer insulating substrate 41 is connected to one of first to third fuse detection terminals (not shown) of the determination unit 51 via a lead.

Each land 47 is connected to a wiring pattern provided in an inner intermediate layer of the multilayer insulating substrate 41 through a plated through hole (not shown), and the wiring pattern is formed of a plated through hole (not shown). ) Is connected to each wiring pattern on the inner surface of the multilayer insulating substrate 41. Each wiring pattern on the inner surface of the multilayer insulating substrate 41 is connected to the other first to third fuse detection terminals (not shown) of the determination unit 51 via leads.

The first to third output terminals of the judgment section 51 are
Via a lead extending from the determination unit 51 or
A wiring pattern connected to the lead, the wiring pattern provided on the inner surface of the multilayer insulating substrate 41, and the FET 49.
, And connected to gates (not shown) of the first to third relays 49a to 49c via leads connected to the wiring pattern. A power input terminal (not shown) for an internal circuit provided on the back surface of the determination unit 51 is connected to the conductive terminal pattern 42 via a plated through hole (not shown) provided in the multilayer insulating substrate 41. Have been.

The three external signal input terminals of the judgment section 51 are connected via leads to first to third signal input terminals 52a to 52c fixed on the inner surface of the multilayer insulating substrate 41. Outer ends of the first to third signal input terminals 52a to 52c are arranged along the inner surface of the multilayer insulating substrate 41, are bent in a crank shape along side edges of the multilayer insulating substrate 41, and From the side.

The first to third signal input terminals 52a to 52
c represents first to third external switch circuits of the vehicle.
When the first to third external switches 30a to 30c are turned on, switch-on signals are input to the determination unit 51, and the first to third external switches 30a to 30c are respectively connected to the first to third external switches 30a to 30c. ~ 3rd external switch 30a
When 30 to 30c are turned off, a switch-off signal is input to the determination unit 51.

As shown in FIG. 5, each member disposed on the multilayer insulating substrate 41 is made of a molding material 53 such as epoxy resin.
, And the entire rare short detector F is formed in a flat hexagonal shape. The outer ends of the first to third conductive terminals 50a to 50c, the first to third signal input terminals 52a to 52c, and the GND connection terminal 55 are exposed from the package.

The judgment section 51 is the judgment section 1 of the first embodiment.
As in the case of No. 6, it is composed of an IC and a microcomputer. Then, in the first embodiment, the determination unit 16 controls the FET (relay) 14 on / off based on the determination of the rare short-circuit of one current sensor (detection unit) 13 and the switch-on signal and the switch-off signal of the external switch 30. Was. On the other hand, in the present embodiment, the first to third detection units 45a
Rare short judgments and the first
Based on the switch-on signal and the switch-off signal of each of the third external switches 30a to 30c, the corresponding relays 49a to 49c are turned on and off. The rare short determination method and the on / off control of the relays 49a to 49c based on the on / off of each of the external switches 30a to 30c in the present embodiment are performed in the same manner as in the first embodiment.

In this embodiment, the judging section 51 constitutes a judging means. The rare short detector F is mounted on a terminal block (not shown) provided in an electric circuit for an automobile. In the case of this circuit, as shown in FIG. Or the relay 49a
To 49c does not operate normally, the first to third detection portions 45a to 45c of the rare short detector F are blown and the circuit is cut off during a normal short circuit in which a large current flows continuously. . The loads 54a to 54c
Include, for example, lamps such as a head lamp and a fog lamp, not shown, a radio, a car audio, and the like.

The rare short detector F configured as described above has the following features. (1) In the present embodiment, a plurality of loads 54a to 54c
First to third detection units 45a to 45c (detection means) are provided for a plurality of circuits including each (electric load).
The judging section 51 (judging means) includes the first to third detecting sections 45a.
A single judgment unit for judging whether or not the current detected by the circuits corresponding to .about.45c is a rare short. Then, first to third relays 49a to 49c (interrupting means) are provided for each circuit, and when the judging section 51 judges that there is an abnormality, the electric circuit including the corresponding loads 54a to 54c is interrupted. And Further, the determination unit 51 includes an external switch 30a for turning on / off the current supply to the loads 54a to 54c of the electric circuits provided corresponding to the plurality of circuits.
30c (external switch circuit) are turned on and off, and the first to third relays 49a to 49c of the corresponding circuit are turned on and off based on the judgment result.

As a result, the judging section 51 judges whether or not the current detected by the circuits corresponding to the first to third detecting sections 45a to 45c is a rare short. , The first to fifth loads 54a to 54c
The third relays 49a to 49c are turned off.

The judging section 51 judges whether the external switches 30a to 30c are turned on / off with respect to the electric loads 54a to 54c of the circuits provided corresponding to the plurality of circuits, and determines the corresponding circuit based on the judgment result. 1st to 3rd relay 49a
４９49c is turned on and off.

As a result, the electric circuit for the automobile can be turned on and off by operating the external switches 30a to 30c. (2) Also in the present embodiment, the interruption means is constituted by the first to third relays 49a to 49c as semiconductor relays. As a result, the configuration can be simplified as the switching element, and the size can be reduced when packaged as the rare short detector F.

(3) Also in the present embodiment, the rare short detector F includes first to third detectors 45a to 45c,
The third relays 49a to 49c and the determination unit 51 are all integrated by a mold package. As a result, it is possible to provide a compact and inexpensive circuit protector that can detect a rare short circuit by using recent electronic technology while making it easy to use in an electric circuit for a vehicle.

The embodiment of the present invention may be modified as follows. (1) FIGS. 6 (a) and 6 (b) and FIGS. 7 (a) and 7 (b)
This is an embodiment in which the rare short detector described in the second embodiment is modified. The electric circuit configuration of these rare short detectors F constitutes substantially the same circuit as the circuit shown in FIG. In each of the drawings, the same reference numerals are given to members having the same configuration or corresponding components as those of the first embodiment and the second embodiment. FIG.
7A and 7B, the conductive terminal 11 is arranged instead of the conductive pattern 42a.

FIG. 6 (a) is based on the assumption that a substrate is mounted in an electric junction box.
a to 50c, the first to third signal input terminals 52a to 52c, and the GND connection terminal 55 extend to the same side, are bent and formed in an L shape on the side surface of the package, and protrude to the outside.

FIG. 7A shows the configuration of FIG. 6A in which the first to third conductive terminals 50a to 50c, the first to third signal input terminals 52a to 52c and the GND connection terminal 55 are inverted L-shaped. It is formed by bending into a shape.

External batteries Ba to Bc are connected to each independent circuit. FIG. 6B shows the first
The third to fifth conductive terminals 50a to 50c, the first to third signal input terminals 52a to 52c, and the GND connection terminal 55 are linearly extended to the same side and protrude outside on the side surface of the package.

In FIG. 6B, the conductor pattern 42
Instead of a, the conductive terminal 11 has the same shape and extends in the same direction as the other conductive terminals 50a to 50c as shown in the figure.

By doing so, FIG. 6B,
In the embodiment shown in FIG. 7B, it is possible to create a compact shape. Further, the circuit shown in FIG. 10 is different from the configuration of the second embodiment in that three circuits are configured as independent circuits. That is, the function is substantially the same as the configuration in which the rare short detector F of the first embodiment is assembled into three circuits.

(2) The embodiment shown in FIGS. 8 and 9
The electric circuit configuration of the multipolar rare short detector F is different from that of the second embodiment. Hereinafter, the differences from the electric circuit of the second embodiment will be mainly described. The second
The same or corresponding components as those of the embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The rare short detector F of the embodiment shown in FIG.
In the main circuit connected to the battery B as shown in the figure, a single relay 49 is connected, and three branch circuits connected to the relay 49 are connected to the first to third detection circuits. The parts 45a to 45c are respectively connected. In addition, a circuit configuration is provided in which three judging units 51a to 51c are separately provided for detecting the voltage between both ends of the first to third detecting units 45a to 45c.

Each of the judging sections 51a to 51c determines the load 5
A switch-on signal or a switch-off signal of an external switch 30a to 30b for turning on / off a circuit including 4a to 54c is input, and the relay 49 is controlled to be turned on / off based on the switch-on signal or the switch-off signal. ing. Each of the determination units 51a to 51c is the first
Based on the detection of the voltage (passing current) across the third detection units 45a to 45c, a rare short is determined. When the rare short is determined, the relay 49 is turned off.

The electric circuit configuration of the present embodiment is integrated with a mold package as in the second embodiment.
Therefore, in this embodiment, all the loads 54a to 54c can be turned on / off by a single relay 49.

(4) The rare short detector F of the embodiment shown in FIG. 9 has three branch circuits connected to the main circuit connected to the battery B as shown in FIG.
The third embodiment is different from the second embodiment in that a circuit configuration is provided in which three determination units 51a to 51c are separately provided for detecting voltages at both ends of the third detection units 45a to 45c.

Accordingly, each of the judging sections 51a to 51c inputs a switch-on signal or a switch-off signal of the external switch 30a to 30b for turning on or off a circuit including each of the loads 54a to 54c, and outputs the switch-on signal or the switch-on signal. On / off control of the relay 49 is performed based on the off signal. Each of the judging sections 51a to 51c judges a rare short based on the detection of the voltage (passing current) across the first to third detecting sections 45a to 45c, and turns off the relay 49 when judging the rare short. Control.

Also in this embodiment, in such an electric circuit configuration, each component is integrated by a mold package. (5) In the first embodiment, a fuse is used as the current sensor 13. However, instead of the fuse as the current sensor, a current sensor such as a commonly used shunt resistor, a thermistor, a current sensor using a Hall element, or the like is used. What is necessary is just to be able to output in proportion to the value.

(6) In the first embodiment, the judgment unit 1
6 is composed of an IC 16A and a microcomputer 16B,
The present invention is not limited to this configuration, and can be configured as an electric circuit such as a logic circuit.

(7) In each of the above embodiments, the FET 14 is used as a semiconductor relay as an example of a relay. However, if the circuit can be turned on / off by a signal, such as a normal mechanical relay, it should be used. Is possible.

Next, technical ideas other than those described in the claims which can be understood from the above-described embodiment and other examples will be described below together with their effects. (1) The detecting means is provided for each of a plurality of circuits provided for each of a plurality of electric loads, and the judging means detects a current detected by a circuit corresponding to each of the detecting means. The circuit comprises a single determining means for determining whether or not there is a short circuit. The interrupting means is provided corresponding to each of the circuits, and responds when the single determining means determines that there is an abnormality. It is configured to cut off the electric circuit,
The single judging means judges whether an external switch circuit for turning on / off a current supply to an electric load of an electric circuit provided corresponding to each of the plurality of circuits is turned on / off, and a corresponding circuit is determined based on the judgment result. 6. The rare short detector according to claim 5, wherein the shutoff means is turned on and off.

In this way, since the configuration is made only by a single judgment means, unlike the case where a plurality of diagnosis means are provided, the number of parts and the mounting space are reduced.
The size can be reduced, and the number of assembling steps is reduced, so that the cost can be reduced.

[0076]

As described in detail above, according to the first to fifth aspects of the present invention, the circuit configuration can be simplified and the cost can be reduced.

According to the second aspect of the present invention, since the detecting means is a fuse, it has the original fuse performance, so that a trouble occurs in the judging means or the relay.
Even if at least one of them does not operate normally, the fuse is blown and the electric circuit can be cut off at the time of a dead short in which a normal continuous large current flows.

According to the third aspect of the present invention, since the interrupting means is constituted by a semiconductor relay, the structure of the interrupting means can be simplified and the package can be downsized.
According to the invention as set forth in claim 4, a detecting unit, a determining unit,
To provide a circuit protector that is easy to use in electric circuits for automobiles, and that uses recent electronic technology to enable more compact and inexpensive rare short-circuit detection, because all the shut-off means are integrated. Can be.

According to the fifth aspect of the present invention, a single or a plurality of judging means for turning on / off an external switch circuit for turning on / off a current supply to an electric load of an electric circuit provided for each of a plurality of circuits. Can be turned on and off based on the result of the judgment.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of an automobile including a rare short detector according to an embodiment.

FIG. 2 is a perspective view showing a schematic configuration of a rare short detector.

FIG. 3 is an electric circuit diagram of an automobile including a rare short detector according to another embodiment.

4 (a) is a plan view of the rare short detector of the embodiment of FIG. 3 without a molding material, FIG. 4 (b) is a front view, FIG. 4 (c) is a right side view, and FIG. 4 (d) is a bottom view. .

FIG. 5 is a right side view of a rare short detector provided with the molding material of the embodiment of FIG. 3;

FIGS. 6A and 6B are perspective views of a rare short detector showing a different layout of the embodiment of FIG. 3;

FIGS. 7A and 7B are perspective views of a rare short detector showing a different layout of the embodiment of FIG. 3;

FIG. 8 is an electric circuit diagram of an automobile including a rare short detector according to another embodiment.

FIG. 9 is an electric circuit diagram of an automobile including a rare short detector according to another embodiment.

FIG. 10 is an electric circuit diagram of an automobile including a rare short detector according to another embodiment.

[Explanation of symbols]

13 ... current sensor (constituting detection means), 14 ... F
ET (constituting interrupting means) 16 ... determining unit (constituting determining means) 29 ... load (electric load), 30 ... external switch (constituting external switch circuit), 30a-30c ... external switch (external) A switch circuit is constituted.), 45a to 45c ... first to third detecting units (constituting detecting means), 49 ... relays (constituting interrupting means), 49a to 49c ... first to third relays. (Construction means), 51 ... determination section (composition of decision means), 51a-51c ... (composition of decision means).

Continued on the front page F-term (reference) 2G014 AA03 AB24 AC19 5G004 AA04 AB03 BA03 BA04 DA02 DC14 EA01 EA03 5G502 AA01 EE04 KK02

Claims (5)

[Claims] 1. A rare short detector installed between a power supply and an electric load in an electric circuit for a vehicle, wherein the detecting means detects a current flowing in the circuit, and the detecting means detects the current flowing in the circuit. A judging means for judging whether or not the current is a rare short circuit, and a shutoff means for shutting off the electric circuit when the judging means judges an abnormality, are internally configured, and the judging means is A rare short circuit which is connectable to an external switch circuit for turning on / off a current supply to an electric load of the circuit, judges whether the external switch circuit is on / off, and turns on / off the cutoff means based on the judgment result. Detector. 2. The apparatus according to claim 1, wherein said detecting means is a fuse.
5. The rare short detector according to 4. 3. The rare short detector according to claim 1, wherein the cutoff means is a semiconductor relay. 4. The apparatus according to claim 1, wherein the detecting means, the judging means, and the shut-off means are integrally packaged.
5. The rare short detector according to 4. 5. The detecting means is provided for each of a plurality of circuits provided for each of a plurality of electric loads, and the judging means is configured to detect a current detected by a circuit corresponding to each of the detecting means. Consists of a single judging means or a plurality of judging means for judging whether or not the circuit is a rare short circuit. When the single or the corresponding judgment means for each circuit judges an abnormality, the corresponding electric circuit is cut off. On / off of an external switch circuit for turning on / off a current supply to an electric load of an electric circuit provided corresponding to each circuit is determined, and based on the determination result, the main circuit or a corresponding circuit shutoff unit is determined. Short circuit detector according to claim 1, characterized in that the on-off.