JPH10322880A - Power supplier for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supplier for a vehicle which can properly protect a power line from current abnormality with simple and efficient constitution. SOLUTION: This device has a main power line 41 which electrically connects a battery 43 with a load 50 driven by the battery 43, a power line 29 for a small current which is arranged closely or through an insulating layer around this main power line 41 and smaller in current capacity than the main power line 41, a fuse 19 which is provided on the power line 29 for a small current and breaks the connection by fusing itself when an abnormal current flows, and a power breaker 35 which is provided on the main power line 41 and is switched from the connection to disconnection when the fusion is detected in the fuse monitor 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a vehicle, which can appropriately protect a power supply line mounted on a vehicle such as an automobile from an abnormal current with a simple configuration.

[0002]

2. Description of the Related Art Recently, with the rapid computerization of vehicles, vehicles, for example, various types of passenger vehicles, have been equipped with essential equipment (hereinafter referred to as "internal combustion engines" and "automatic transmissions") essential for operation. Electronic circuits and electronic devices including a microcomputer are mounted from the viewpoints of improving fuel efficiency of the main engine, reducing exhaust gas, running smoothly, and driving safely. In addition, the instrumentation of the front panel is replaced with an electronic display device, for example, a color liquid crystal display device, so that the operation state of the vehicle can be more easily recognized and various information of the vehicle can be provided in various forms. Have also been tried. Furthermore, there is a high demand for not only a mere means of transportation but also the use of a vehicle as a living space, aiming at further improvement of ride comfort and convenience as a means of transportation. Position assessment / operation guide device used, automatic seat adjustment device, power window, wiper, door lock, various lamps,
2. Description of the Related Art Increasing mounting of auxiliary devices and devices (hereinafter, auxiliary devices) such as radios, CDs, TV devices, and entertainment facilities, and electronic control of them are progressing.

As described above, as the electrical components, the main engine, and the auxiliary equipment mounted on the vehicle are electronically controlled, the electric components, the main engine, and the auxiliary equipment themselves are electrically driven, and the main engine is increased. Various electronic devices are mounted on a vehicle for electronic control of auxiliary equipment. Therefore, for the above devices and devices mounted on the main engine, power transmission in a vehicle and signal transmission for operating an electronic control device have become important.

However, in power supply and signal transmission in a vehicle, a power supply line and a signal line (wire harness) pass through a rotating part such as a door, pass through a moving part or the like, fit into a narrow part, and are screwed. Because it may stop at a location or pass through a high-temperature and high-humidity area, there is a high possibility of short-circuiting (short-circuit) due to deterioration, breakage, or the like, compared to ordinary indoor wiring. When a power supply line or a signal line is short-circuited, an abnormal current may flow through these lines. Conventionally, as shown in FIG.
Power line 3 arranged between battery 2 and load 6
A large-capacity main fuse 4 and a small-capacity sub-fuse 5 are provided in series, and when an abnormal current flows, the current is cut off by fusing of the fuses 4, 5, and the power supply line 3 is cut off.
Is protected.

However, the fuse does not blow unless the abnormal current continues for a certain period of time. Therefore, according to the above-mentioned method, the fuse is not blown in a rare short circuit in which an abnormal current occurs intermittently as shown in FIG. Cannot be properly protected. Further, the drive circuit and control circuit of the main engine or the auxiliary machine may be damaged by the abnormal current.

In order to solve such a problem, as shown in FIG. 16, a system has been proposed in which a cutoff switch 10 and a minute resistance 8 for current measurement are inserted into a power supply line 11 connecting a battery 2 and a load 6. ing. In this system, when an abnormal current flows through the power supply line 11, this abnormality appears in the potential difference between the points a and b on both sides of the current measuring minute resistor 8. The current monitoring circuit 9 detects a potential difference between the points a and b, and when it determines that an abnormal current is flowing from the potential difference, excites the coil 10a of the cutoff switch 10 and switches the switch 10b to the open state. Figure 3? According to the system shown in FIG. The power supply line 11 can be appropriately protected by detecting the rare short circuit shown in FIG. 1 and controlling the cutoff switch 10 based on the detection result.

By the way, the system shown in FIG. 16 requires a countermeasure against heat generation of the current measuring micro-resistor 8, and has a problem that if the capacity of the power supply line 11 becomes large, the apparatus becomes large-scale and expensive. .

Therefore, in order to further solve the problem of the system shown in FIG. 16, as shown in FIG. 17, an interference detecting wire 21 such as a copper foil tape is provided around the inner conductor 20 via an insulating layer 22. A system for detecting interference by using the wound power supply line with the configuration shown in FIG. 18 has been proposed. In this system, when the internal conductor 20 is short-circuited to the body, prior to that, the interference detection wire 21 is short-circuited to the body, and the potential of the interference detection wire 21 is reduced to the ground and becomes lower than the reference potential Vref. The output voltage reverses from negative to positive.
The logic circuit 92 detects that the interference detection wire 21 has short-circuited (interference) with the body by monitoring the output voltage of the operational amplifier 73, and switches the cutoff switch 25 based on the detection result. However, in this system, the interference detection wire 21 is used only for interference detection, and the system is wasteful and not economical.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a vehicle power supply device capable of appropriately protecting a power supply line from abnormal current with a simple and efficient configuration.

[0010]

According to the present invention, in order to achieve the above-mentioned object, a power supply apparatus for a vehicle according to the present invention electrically connects a power supply to equipment mounted on a vehicle driven by the power supply. A main power supply line, a single power supply line or a plurality of small current power supply lines disposed near or via an insulating layer around the main power supply line and having a smaller current capacity than the main power supply line; A first connection disconnecting unit that is provided at a predetermined position on the power supply line and disconnects connection when an abnormal current flows through the small current power supply line; When the first connection cutoff means switches from the connection state to the cutoff state, the second connection cutoff means switches from the connection state to the cutoff state in conjunction therewith.

In the vehicle power distribution device of the present invention, for example, in a normal state, both the first connection breaking means and the second connection breaking means are in a connected state, and the power supply is connected via the main power supply line. Is supplied to the on-vehicle equipment, and the power for driving the electronic circuit is supplied through the power supply line for small current.
It is supplied to electronic circuits that control the drive of vehicle-mounted equipment. On the other hand, when, for example, a short-circuit to the body occurs at a certain position on the main power supply line, the small-current power supply line short-circuits to the body prior to the short-circuit, and an abnormal current flows through the small-current power supply line. Due to this abnormal current, the first connection interrupting means is switched to the interrupted state. In addition, in response to the switching, the second connection disconnecting unit also switches to the disconnection state. As a result, the connection between the power supply via the main power supply line and the on-vehicle equipment is cut off, and it is possible to prevent excess current from flowing from the power supply to the short-circuited portion via the main power supply line. At this time, the small current power supply line has a function of supplying a power supply for driving an electronic circuit, in addition to a function of detecting a short circuit of the main power supply line in advance.

In the power supply device for a vehicle according to the present invention, preferably, the first connection disconnecting means disconnects from the connection state when a current flowing through the small current power supply line exceeds a predetermined current value. Switch to state.

[0013] In the power supply device for a vehicle according to the present invention, preferably, the first connection breaking means is a fuse, and the second connection breaking means detects whether the fuse has blown. And a control means for switching the switch from the closed state to the open state when the fusing detection means detects the fusing.

Further, in the power supply device for a vehicle according to the present invention, preferably, the first connection cut-off means is an intelligent power switch constituted by using a semiconductor.

Further, in the power supply device for a vehicle according to the present invention, preferably, the second connection disconnecting means includes a relay switch.

In the power supply device for a vehicle according to the present invention, preferably, the power line for small current is a line for supplying power for driving an electronic circuit.

The power supply device for a vehicle according to the present invention may be configured such that a power supply, a main power supply line for electrically connecting a vehicle-mounted device driven by the power supply, and a transmission means and a reception means. A single or a plurality of signal transmission lines disposed near or via an insulating layer around the main power supply line and having a smaller current capacity than the main power supply line, and the receiving means via the signal transmission line; Abnormality detection means for determining whether the received signal is abnormal,
A connection disconnecting unit that is provided at a predetermined position on the main power supply line and that switches from a connected state to a disconnected state when the abnormality detecting unit detects an abnormality.

Further, in the vehicle power supply device of the present invention, preferably, the signal transmission line is a multiplex signal line.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a power supply device for a vehicle according to an embodiment of the present invention will be described. First Embodiment FIG. 1 is a configuration diagram of a vehicle power supply device 31 according to the present embodiment. As shown in FIG. 1, in the vehicle power supply device 31, the battery 43 and the power supply unit 32 are connected via the main power line 28, and the power supply unit 32 and the power supply unit 33 connect the main power line 41. And the power supply unit 32 and the load 50 are connected via a main power supply line 42. Here, the main power supply line 41 is
Together with the small current power supply line 29, it is incorporated in the power supply line 51.

In the power supply section 32, the positive electrode of the battery 43 is connected to the fuse 1 via the main power supply line 28.
9. Switch 35a and coil 35 of power cutoff unit 35
b are connected in parallel at one end. In addition, battery 4
The third positive electrode is further connected to the fuse blowing monitor 26 and the power supply circuit 34 for electronic components. In addition, the positive electrode of the battery 43 is connected to the alternator AL
The alternator ALT is connected to the output of T and supplies power to a load and a control unit connected to the positive electrode of the battery 43 when the engine rotates, and charges the battery 43 with the surplus power.

The other end of the fuse 19 is connected to one end of a small current power supply line 39. Power line 3 for small current
The other end of 9 is connected to a small current power line 49 via a small current power line 29. Here, the small current power supply lines 39, 29, and 49 supply a drive power supply for backing up a memory or driving the electronic circuit from the battery 43 to the electronic component power supply circuit 34, and have a current capacity of 10A. The main power supply lines 28, 41, 42
Is smaller than the current capacity of 50 to 100A. As the fuse 19, for example, a fuse having a small capacity that is blown by a current of 10 A or less is used. Both ends of the fuse 19 are also connected to a fuse blowing monitor 36. The fuse blowing monitor 36 detects whether or not the fuse 19 has blown by the potential monitoring means on the fuse downstream side, and outputs the detection result to the logic circuit 37.

The other end of the switch 35a is connected to the main power line 4
1 is connected to one end. The other end of the coil 35b is connected to the logic circuit 37 via the inverter 38.
The electronic component power supply circuit 34 is also connected to the logic circuit 37. The electronic component power supply circuit 34 is
The DC-DC conversion converts the 12V power supply voltage supplied from the PDC to a 5V electronic circuit driving voltage, and supplies this to the logic circuit 37. The logic circuit 37 is driven by the electronic circuit driving voltage. When the detection result S19 from the fuse blowing monitor 36 indicates that the fuse has blown, the logic circuit 37 outputs the coil 35b via the inverter 38.
And the switch 35a is opened. On the other hand, when the detection result S19 from the fuse blowing monitoring unit 36 indicates that the fuse has not blown,
The coil 35b is excited, and the switch 35a is closed.

In the power supplied section 33, the main power supply line 41
Are connected to one end of the switch 45a and one end of the coil 45b in the power cutoff unit 45. The other end of the switch 45a is connected to the load 50 via the main power supply line 42. The other end of the coil 45b is connected to a logic circuit 47 via an inverter 48. Further, the other end of the small current power supply line 49 is connected to the electronic component power supply circuit 44.
, And the electronic component power supply circuit 44 is connected to the logic circuit 47. The logic circuit 47 is connected to the logic circuit 37 via the signal line 55.

FIG. 2 is an internal configuration diagram of the power supply line 51. As shown in FIG. 2, a power supply line 51 includes an insulator 52 such as PVC around a main power supply line 41 which is a central conductor.
The power supply line 29 for a small current such as a power supply for an ECU is covered around the insulator 52, and the resin 5 is further surrounded therearound.
3 is coated.

In the following, when there is no abnormality in the power supply line 51 for explaining the function of the vehicle power supply device 31, as shown in FIG. 1, the logic circuits 37 and 47 are connected via inverters 38 and 48, respectively. The coils 35b and 45b are demagnetized, and the switches 35a and 45a are open. Therefore, when the coil 45b is excited by the logic circuit 47 and the switch 45a is closed,
The power supply current from the battery 43 is
The power is supplied to the load 50 via the power cutoff unit 35, the main power line 41, the power cutoff unit 45, and the main power line 42. Further, a drive current for electronic components is supplied from the main power supply line 28 to the electronic component power supply circuit 44 via the fuse 19, the small current power supply line 39, and the small current power supply line 29.

By the way, for example, when the point a on the main power supply line 41 shown in FIG. 1 is short-circuited to the body, the small-current power supply line 29 is short-circuited to the body, that is, the ground, and Power supply line 39,
Excess current flows through 29 and 49. Therefore, fuse 1
The fuse 9 is blown, and the blow is detected by the fuse blow monitoring unit 36. At this time, as the fuse 19, 10
Since a capacitor having a small capacity of A or less is used, an intermittent short (rare short) is sensitively detected, and the fuse 1
9 can be blown.

Then, a detection result S indicating that the fusing was performed.
19 is output from the fuse blowing monitor 36 to the logic circuit 37. When the detection result S19 is input, the logic circuit 37 demagnetizes the coil 35b via the inverter 38, and switches the switch 35a to the open state as shown in FIG. As a result, the main power supply line 28 and the main power supply line 41 become non-conductive, and even if the main power supply line 41 is short-circuited, no abnormal current flows through the main power supply line 41.
Further, since the fuse 19 is blown, the main power supply line 28 and the small current power supply line 39 are in a non-conductive state, and no abnormal current flows through the small current power supply line 29.

As described above, according to the vehicle power supply device 31, the main power supply line 41 is monitored by monitoring the fusing of the fuse 19 connected to the small current power supply line 29.
Can be detected in advance and the short-circuited portion can be separated. Further, according to the vehicle power supply device 31, the small current power supply line 29 is provided with the function of supplying the power for driving the electronic components in addition to the short-circuit monitoring function. It can be configured.

In the vehicle power supply 31,
As shown in FIG. 4, the power supply line 51 covers the main power supply line 41, which is the central conductor, with an insulator 52 such as PVC, and the small current power supply line 29 is spirally wound around the insulator 52. Alternatively, a configuration may be adopted in which the resin 53 is further coated around the periphery.

Second Embodiment FIG. 5 is a diagram showing the configuration of a vehicle power supply 81 according to this embodiment. In FIG. 5, the same components as those of the vehicle power supply device 31 are denoted by the same reference numerals as those in FIG. In the vehicle power supply device 81, an IPS (Intelligent Power S
witch) 61 and the logic circuit 67 are connected. IP
S61 and the logic circuit 77 of the power supplied section 63 are connected via a small current power supply line 71. The switch 35a of the power cutoff unit 35 and the switch 4 of the power cutoff unit 45
5a is connected via the main power supply line 72.
The logic circuit 67 and the logic circuit 77 are connected via a multiplex transmission line 73. Here, the small current power supply line 71 and the main power supply line 72 are, for example, like the power supply line 51 shown in FIG. It is wound up and incorporated in one power supply line 78.

The IPS 61 monitors the current flowing through the small-current power supply line 71, determines that the current flows through the small-current power supply line 71 even if the current flows abnormally even within the overcurrent or the rated current, and determines the current flowing through the small-current power supply line 71. It is composed of a semiconductor element to be shut off.
The IPS 61 outputs to the logic circuit 67 an IPS abnormality signal S61 that generates a pulse when it is determined that the current is abnormal. FIG. 6 is a configuration diagram of the IPS 61. As shown in FIG. 6, the IPS 61 transmits, for example,
It has an input logic 200 for inputting the S drive signal S67a, a drive circuit 201, and an output circuit 202. The output of the output circuit 202 drives or stops the power supply to the small current power supply line 71. The IPS 61 includes a protection circuit 203 and a diagnosis circuit 204. The protection circuit 203 protects electronic circuits and the like in the IPS 61 from excessive current and excessive voltage. Diagnostic circuit 20
4 diagnoses the state of the internal circuit. For the actual product of the IPS 61, see, for example, TPD1004S manufactured by Toshiba. The IPS 61 receives the IPS drive signal S67a from the logic circuit 67, enters the drive state when the IPS drive signal S67a is at a high level, and enters the stop state when the IPS drive signal S67a is at a low level. The IPS 61 may monitor the heat generation and cut off the current.

FIG. 7 is a configuration diagram of the logic circuit 47. As shown in FIG. 7, the logic circuit 47 includes a DC-DC converter 82, a microcomputer 83, and a multiplex transmission circuit 84.
And a bus interface circuit 85. DC
The -DC converter 82 converts a 12V power supply voltage input from the battery 43 via the main power supply line 28 into a 5V electronic circuit driving voltage, and supplies this to the microcomputer 83. The microcomputer 83 is a DC
-Driven by the voltage for driving the electronic circuit from the DC converter 82, and when a pulse generated in the IPS abnormality signal S61 is detected as described later, the coil 35b is demagnetized via the inverter 38 and the switch 35a is opened. .
The microcomputer 83 includes the multiplex transmission circuit 8
4. A multiplexed signal is output to the logic circuit 77 via the bus interface circuit 85 and the multiplex transmission line 73.

The operation of the vehicle power supply 81 will now be described with reference to FIGS. FIG. 8 is a timing chart of each signal and the potential of the line when the power supply line 78 shown in FIG. 5 is damaged at point a. When the power supply line 78 shown in FIG. 5 is broken at the point a, first, the small current power supply line 71 is short-circuited to the body,
As shown in FIG. 8C, at time t1, the potential of the small-current power supply line 71 decreases, and an excess current flows through the small-current power supply line 71. This excess current is caused by the IPS61
At time t2, as shown in FIG.
Then, a pulse is generated in the IPS abnormality signal S61. When detecting the pulse included in the IPS abnormality signal S61, the logic circuit 67 switches the IPS drive signal S67a and the relay drive signal S67b from high level to low level at time t3. As a result, the IPS 61 maintains a state in which the main power supply line 28 and the small current power supply line 71 are cut off, the coil 35b of the power cutoff unit 35 is demagnetized, the switch 35a is opened, and the main power supply line 72 is turned off. The potential switches from high level to low level.

As described above, according to the vehicle power supply device 81, the I power supply line 71 connected to the small current power supply line 71.
Based on the detection result from the PS 61, the main power line 71
Can be detected in advance and the short-circuited portion can be separated. Further, according to the vehicle power supply device 81, the small current power supply line 71 is provided with a function of transmitting a drive current for electronic components in addition to a short-circuit monitoring function. It can be configured.

Third Embodiment FIG. 9 is a configuration diagram of a vehicle power supply device 91 according to this embodiment. As shown in FIG.
6, a terminal 110 including a multiplex transmission circuit 92, a control circuit 93, and a bus interface 94 is provided on the left side of the figure. Also, the multiplex transmission line 9
6, 97, on the right side of the figure, the multiplex transmission circuit 102,
A terminal 111 including a control circuit 103 and a bus interface 104 is provided. Here, the multiplex transmission circuit 92 and the control circuit 93 are connected via a data transmission line 95 and an abnormal signal line 98, and the multiplex transmission circuit 92 and the bus interface 94 are connected to a transmission line Tx
And a receiving line Rx. Further, the bus interface 94 and the control circuit 93 are connected via an abnormal signal line 99.

Although not shown in FIG. 9, the terminal 110
As shown in FIG. 10, a main power supply line 112 and a circuit driving power supply line 113 are arranged between the terminal 111 and the terminal 111 in addition to the multiplex transmission lines 96 and 97. These lines connect both the main power supply line 112 and the circuit driving power supply line 113 to the multiplex transmission line 9 located in parallel.
6, 97 are wound, covered with a protective layer 114, and incorporated in a wire harness 115. Incidentally, the multiplex transmission lines 96 and 97 may be incorporated in the wire harness 115 so as to form a twisted pair line. Thus, the multiplex transmission line 96 and the multiplex transmission line 97
Using. As will be described later, by transmitting substantially the same signals whose levels are inverted from each other, it is possible to suppress the influence of common-mode noise generated during transmission, and even if one of the multiplex transmission lines is short-circuited, the other multiplex transmission line is short-circuited. A signal can be transmitted via a transmission line.

The multiplex transmission circuit 92 is connected to the data transmission line 9
5 is converted into a time-division serial signal as shown in FIG. 11A, and the serial signal is output to the bus interface 94 via the transmission line Tx. In this serial signal, the first two bits indicate the start of the data body,
The next 8 bits indicate the data body. For the modulation of the data body, one bit is divided into three phases, the first phase is always at a high level, the second phase is at a low level or a high level according to the value of data, and the third phase is (Pulse Width Modulat) that always sets the low level
ion).

FIG. 12 is a configuration diagram of the bus interface 94. The bus interface 10 of the terminal 111
4 has the same configuration as the bus interface 94.
As shown in FIG. 12, in the bus interface 94,
Transmission circuit 94a, reception circuit 94b, and reception circuit 94c
Is built-in. In the transmission circuit 94a, the transmission line Tx is connected to the current source 121 and to the current source 122 via the inverter 120. Therefore, a voltage corresponding to the level of the transmission line Tx is applied to the current source 12.
1 and a voltage corresponding to the level obtained by inverting the level of the transmission line Tx is applied to the current source 122.

The current sources 121 and 122 supply currents proportional to the applied voltage to transmission lines 123 and 124, respectively.
Output to Here, the transmission line 123 is connected to the ground via the resistor 136, and the transmission line 124 is connected to the resistor 1
It is connected to the power supply voltage via 35. FIG. 11 (A)
Is input to the current source 121 via the transmission line Tx, the current output from the current source 121 to the transmission line 123 varies according to the serial signal, and the bias of the resistor 136 is changed. Depending on the function, the potentials of transmission line 123 and multiplex transmission line 96 are
1 (B). When a serial signal obtained by inverting the time-division serial signal shown in FIG. 11A is input to the current source 122 via the inverter 120, the transmission line 124 and the multiplex transmission line 97 are activated by the bias function of the resistor 135. Is as shown in FIG. 11 (C).

In the receiving circuit 94b, the transmission line 123 is connected to one input terminal of the pulse level setting circuit 129 via the capacitor 125, and the output terminal is connected to the + input terminal of the comparator 131. I have. Further, the transmission line 124 is connected to the other input terminal of the pulse level setting circuit 129 via the capacitor 126, and the output terminal is connected to the negative input terminal of the comparator 131. The comparator 131 outputs a differential voltage between the potential of the + input terminal and the potential of the − input terminal as a reception signal from the output terminal to the reception line Rx. The received signal is also output to one input terminal of the exclusive OR (XOR) circuit 133. Here, the receiving circuit 94b
Even when a failure such as a short circuit occurs in one of the multiplex transmission lines 96 and 97, the reception signal received via the other multiplex transmission line is determined and the reception line Rx
The level of the received signal is set in the pulse level setting circuit 129 so that the signal is output to the multiplex transmission circuit 92 via the. The multiplex transmission circuit 92 converts the received signal input via the reception line Rx from a serial signal to a parallel signal, and outputs the signal to the control circuit 93 via the data transmission line 95.

Further, in the receiving circuit 94c, the transmission line 123 is connected to one input terminal of the pulse level setting circuit 130 via the capacitor 127, and the output terminal thereof is connected to the + input terminal of the comparator 132. I have. The transmission line 124 is connected to the other input terminal of the pulse level setting circuit 130 via the capacitor 128, and the output terminal is connected to the-input terminal of the comparator 132. The comparator 132 outputs, as a reception signal, a difference voltage between the potential of the + input terminal and the potential of the − input terminal from the output terminal to the other input terminal of the exclusive OR circuit 133. Here, the receiving circuit 94c
The level of the received signal is set by the pulse level setting circuit 130 so that the received signal cannot be determined unless an accurate received signal is received from both the multiplex transmission lines 96 and 97.

The exclusive OR circuit 133 receives the received signal from the output terminals of both the comparator 131 and the comparator 132, calculates the exclusive OR thereof, and sets the result of the calculation as an abnormal signal to the abnormal signal line 99. The signal is output to the control circuit 93 via the control circuit 93. Specifically, the abnormal signal from the exclusive OR circuit 133 is at a high level if both of the received signals are the same, and is at a low level if they are different.

The vehicle power supply 91 shown in FIG.
The operation when the multiplex transmission line 97 interferes with the body at the point a and is short-circuited to the ground will be described. FIG.
7 is a waveform diagram of each signal of the vehicle signal transmission device 91 when the multiplex transmission line 97 is short-circuited at a point a. Note that the short circuit of the multiplex transmission lines 96 and 97 usually occurs due to the structure of the wire harness 115 shown in FIG.
This occurs prior to the short circuit of the power supply line 113 and the circuit driving power supply line 113. When the point a on the multiplex transmission line 96 is short-circuited at time t1 shown in FIG. 13, the potential waveforms of the transmission signals S96 and S97 transmitted from the terminal 110 to the terminal 111 via the multiplex transmission lines 96 and 97 are shown in FIG. 13
(A) and (B) are obtained. At this time, in the bus interface 104 of the terminal 111, based on the transmission signal S97 received via the multiplex transmission line 97, the reception circuit corresponding to the reception circuit 94b shown in FIG. A signal SRx is generated, and the received signal SRx is output to the multiplex transmission circuit 102 via the reception line Rx.

On the other hand, the abnormal signal S150 generated in the receiving circuit corresponding to the receiving circuit 94c shown in FIG.
As shown in FIG. 13D, at time t1, the level switches from the high level to the low level. When the control circuit 103 detects that the abnormal signal S150 input from the receiving circuit 94c has been switched from high level to low level, the control circuit 103 shown in FIG.
As shown in (E), the relay drive signal is switched from high level to low level. This relay drive signal is output from control circuit 103 to a relay switch (not shown) provided on main power supply line 112 shown in FIG. This relay switch switches from the connected state to the cutoff state when the relay drive signal switches from the high level to the low level. Accordingly, the potential of the main power supply line 112 falls from 12 V to 0 V as shown in FIG. Note that a relay switch may be provided on the circuit driving power supply line 113 shown in FIG. 10 and the relay switch may be turned off based on a relay driving signal from the control circuit 103.

By the way, at the point a shown in FIG. 9, when both the multiplex transmission lines 96 and 97 are simultaneously short-circuited,
The bus interface 104 does not receive any transmission signal. The control circuit 103 includes a bus interface 104
Switches the relay drive signal from high level to low level and shuts off the main power supply line 112 when no transmission signal is received for a certain period of time. For example, when the communication cycle is 50 ms and the transmission signal is not received for 100 ms, the control circuit 103 switches the relay drive signal from the high level to the low level.

As described above, according to the vehicle power supply device 91, the main power supply line 112 and the circuit drive circuit shown in FIG. 10 are used based on the reception result received by the terminal 111 via the multiplex transmission lines 96 and 97. A short circuit of the power supply line 113 can be detected in advance, and the short circuit portion can be separated. Further, according to the vehicle power supply device 91, the multiplex transmission lines 96 and 97 have a multiplex signal transmission function in addition to the short-circuit monitoring function, and can have a simple system configuration without waste.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the power supply unit and the power supply unit and the data communication between the two terminals have been exemplified. However, a single power supply unit and a plurality of power supply units are connected. The present invention can also be applied to a case where three or more terminals are connected in a many-to-many or one-to-many manner.

In the above-described embodiment, the fuse and the IPS are exemplified as the first connection breaking means. However, if the abnormality is detected in the small current power supply line and the connection is broken, the other connection breaking means is used. Blocking means may be used.

[0049]

As described above, according to the power supply apparatus for a vehicle, the connection between the power supply via the main power supply line and the equipment mounted on the vehicle is cut off before the main power supply line fails. It is possible to prevent an excess current from flowing from the power supply to the fault location via the line. Further, according to the vehicle power supply device of the present invention, the power supply line for small current and the signal transmission line have a function of supplying a power supply for driving an electronic circuit in addition to a function of detecting a short circuit of the main power supply line in advance. And a signal transmission function, so that a simple and lean system configuration can be achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram in a normal state of a vehicle power supply device according to a first embodiment of the present invention.

FIG. 2 is an internal configuration diagram of a power supply line shown in FIG. 1;

FIG. 3 is a configuration diagram when the vehicle power supply device shown in FIG. 1 is in an abnormal state.

FIG. 4 is another internal configuration diagram of the power supply line shown in FIG. 1;

FIG. 5 is a configuration diagram of a vehicle power supply device according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of an IPS.

FIG. 7 is a configuration diagram of the logic circuit shown in FIG. 5;

FIG. 8 is a timing chart of each signal and the potential of the line when a break occurs at a point a of the power supply line shown in FIG. 5;

FIG. 9 is a configuration diagram of a vehicle power supply device according to a third embodiment of the present invention.

FIG. 10 is a view for explaining a structure of a wire harness incorporating the multiplex transmission line shown in FIG. 9;

11A is a waveform diagram of a transmission signal transmitted through a transmission line Tx, FIG. 11B is a waveform diagram of a current flowing through a first transmission line, and FIG. 11C is a waveform diagram of a current flowing through a second transmission line. It is a waveform diagram of a current.

FIG. 12 is a configuration diagram of a bus interface shown in FIG. 9;

FIG. 13 is a waveform diagram of each signal and line when the first multiplex transmission line is short-circuited at point a shown in FIG. 9;

FIG. 14 is a diagram for explaining a conventional vehicle power supply device.

FIG. 15 is a diagram for explaining a rare short circuit that occurs in a power supply line.

FIG. 16 is a diagram for explaining another conventional vehicle power supply device.

FIG. 17 is a diagram for explaining the structure of an interference detection wire used in a conventional vehicle power supply device.

FIG. 18 is a diagram for explaining a vehicle power supply device using the interference detection wire shown in FIG. 17;

[Explanation of symbols]

 31, 81, 91 Vehicle power supply device 29, 71 Power line for small current 32, 62 Power supply unit 33, 63 Power supply unit 41, 72 Main power line 43 Battery 35, 45 Power supply Breaking unit 50 Load 51 Power line 73 Multiple transmission line 96, 97 Multiple transmission line 110, 111 Terminal

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 10, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

In order to solve such a problem, as shown in FIG. 16, a system has been proposed in which a cutoff switch 10 and a minute resistance 8 for current measurement are inserted into a power supply line 11 connecting a battery 2 and a load 6. ing. In this system, when an abnormal current flows through the power supply line 11, this abnormality appears in the potential difference between the points a and b on both sides of the current measuring minute resistor 8. The current monitoring circuit 9 detects a potential difference between the points a and b, and when it determines that an abnormal current is flowing from the potential difference, excites the coil 10a of the cutoff switch 10 and switches the switch 10b to the open state. According to the system shown in FIG. 16, a rare short as shown in FIG. 15 is detected, and the power supply line 11 can be appropriately protected by controlling the cutoff switch 10 based on the detection result.

Claims (8)

[Claims] A main power supply line for electrically connecting a power supply to on-vehicle equipment driven by the power supply; and a main power supply arranged near or via an insulating layer around the main power supply line. One or more small-current power lines having a smaller current capacity than the line, and provided at a predetermined position on the small-current power line, and when an abnormal current flows through the small-current power line, the connection is cut off. A first connection disconnecting means that is provided at a predetermined position on the main power supply line, and when the first connection disconnecting means switches from a connected state to a disconnected state,
The second that switches from the connected state to the cutoff state in conjunction with it
Power supply device for a vehicle, comprising: 2. The method according to claim 1, wherein the first disconnection means is configured to: when a current flowing through the small current power supply line exceeds a predetermined current value,
The power supply device for a vehicle according to claim 1, wherein the power supply device switches from a connected state to a cutoff state. 3. The first connection cutoff means is a fuse. The second connection cutoff means is a blowout detection means for detecting whether the fuse is blown, a switch, and the blowout detection means. 3. The power supply device for a vehicle according to claim 2, further comprising control means for switching the switch from the closed state to the open state when the switch detects the fusing. 4. The power supply device for a vehicle according to claim 1, wherein said first connection disconnecting means is an intelligent power switch formed using a semiconductor. 5. The power supply device for a vehicle according to claim 1, wherein said second connection disconnecting means comprises a relay switch. 6. The vehicle power supply device according to claim 1, wherein said small current power supply line is a line for supplying a power supply for driving an electronic circuit. 7. A power supply, a main power supply line for electrically connecting a vehicle-mounted device driven by the power supply, and a power supply line adjacent to or around the main power supply line for connecting transmission means and reception means. One or more signal transmission lines arranged with an insulating layer therebetween and having a smaller current capacity than the main power supply line; and whether or not the signal received by the receiving means via the signal transmission line is abnormal. A power supply device for a vehicle, comprising: an abnormality detecting means for determining whether an abnormality has occurred; and a connection interrupting means which is provided at a predetermined position on the main power supply line and switches from a connected state to a disconnected state when the abnormality detecting means detects an abnormality. 8. The vehicle power supply according to claim 7, wherein said signal transmission line is a multiplex signal line.