JP3644792B2 - Vehicle power supply device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply device for a vehicle that can appropriately protect a power supply line installed in a vehicle such as an automobile from an abnormal current with a simple configuration.
[0002]
[Background Art and Problems to be Solved by the Invention]
Recently, with the rapid computerization of vehicles, for vehicles, for example, various passenger cars, improvement of fuel consumption of main equipment (hereinafter referred to as main engine) essential for operation of internal combustion engine, automatic transmission, etc., reduction of exhaust gas. From the viewpoints of smooth running, safe running, etc., electronic circuits and electronic devices including a microcomputer are mounted. In addition, the front panel instruments are replaced with electronic display devices, for example, color liquid crystal display devices, to make it easier to recognize the operation state of the vehicle and to provide various types of vehicle information. There are also attempts. Furthermore, there is a high demand for using the vehicle not only as a moving means but also as a living space as well as improving the ride comfort and convenience of the vehicle as a moving means. Auxiliary equipment / equipment (hereinafter referred to as “auxiliary”) such as position evaluation / operation guidance device, automatic seat adjustment device, power window, wiper, door lock, various lamps, radio, CD, TV device, entertainment facility, etc. Increasing mounting and electronic control of them are progressing.
[0003]
As described above, as the electrical equipment, the main engine, and the auxiliary equipment mounted on the vehicle are electronically controlled, the number of parts in which the electrical equipment, the main equipment, and the auxiliary equipment are electrically driven increases, and the main equipment and the auxiliary equipment. Various electronic devices are mounted on the vehicle for electronic control. Therefore, for the devices and devices mounted on the main engine, power transmission in the vehicle and signal transmission for operating the electronic control device have become important.
[0004]
However, in power feeding and signal transmission in a vehicle, the power line and signal line (wire harness) pass through a rotating part such as a door, pass through a moving part, etc., fit into a narrow part, or stop with a screw. Since it may pass through hot and humid parts, there is a higher possibility of a short circuit due to deterioration, breakage, etc. than ordinary indoor wiring. When the power supply line or the signal line is short-circuited, an abnormal current may flow through these lines. Conventionally, as shown in FIG. 14, a large-capacity main fuse 4 and a small-capacity sub-fuse 5 are provided in series on a power supply line 3 disposed between a battery 2 and a load 6, and an abnormal current flows. When the fuses 4 and 5 are blown, the current supply is cut off to protect the power supply line 3.
[0005]
However, since the fuse does not blow unless the abnormal current continues for a certain period of time, in the above-described method, the fuse is not blown in the rare short in which the abnormal current is intermittently generated as shown in FIG. There is a problem that it cannot be protected. Further, the drive circuit and control circuit of the main machine or auxiliary machine may be damaged by the abnormal current.
[0006]
In order to solve such a problem, as shown in FIG. 16, a system has been proposed in which a cut-off switch 10 and a current measuring micro-resistor 8 are inserted in a power supply line 11 connecting a battery 2 and a load 6. . In this system, when an abnormal current flows through the power supply line 11, this abnormality appears in the potential difference between points a and b on both sides of the current measuring microresistor 8. When the current monitoring circuit 9 detects the potential difference between the points a and b and determines that an abnormal current is flowing from the potential difference, the current monitoring circuit 9 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, it is possible to detect the short circuit as shown in FIG. 15 and control the cutoff switch 10 based on the detection result to appropriately protect the power supply line 11.
[0007]
Incidentally, the system shown in FIG. 16 needs to take measures against heat generation of the current measuring micro-resistor 8, and there is a problem that when the capacity of the power supply line 11 is increased, the apparatus becomes larger and more expensive.
[0008]
Therefore, in order to further solve the problem of the system shown in FIG. 16, as shown in FIG. 17, a power source in which an interference detection electric wire 21 such as a copper foil tape is wound around the outer periphery of the inner conductor 20 via an insulating layer 22 A system for detecting interference using a 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, the interference detection wire 21 is short-circuited to the body, and the potential of the interference detection wire 21 is lowered to the ground and becomes lower than the reference potential Vref. The output voltage is inverted from minus to plus. The logic circuit 92 monitors the output voltage of the operational amplifier 73 to detect that the interference detection wire 21 is short-circuited (interfered) with the body, and switches the cutoff switch 25 based on the detection result. However, in this system, the interference detection electric wire 21 is used only for interference detection, and the system is wasteful and not economical.
[0009]
The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a vehicular power supply device that can appropriately protect a power supply line from a current abnormality with a simple and efficient configuration.
[0010]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a vehicle power supply apparatus according to the present invention, wherein a main power line for electrically connecting a power source and a vehicle-mounted equipment driven by the power source, and the main power source One or a plurality of small current power supply lines disposed near the line or via an insulating layer and having a smaller current capacity than the main power supply line, and provided at predetermined positions on the small current power supply line When an abnormal current flows through the small current power line, a first connection blocking means for cutting the connection and a predetermined position on the main power supply line are provided, and the first connection blocking means is disconnected from the connected state. And a second connection blocking means for switching from the connected state to the blocked state in conjunction with the switching to the blocked state.
[0011]
In the power distribution device for a vehicle according to the present invention, for example, at the normal time, both the first connection blocking means and the second connection blocking means are in a connected state, and the power is mounted on the vehicle via the main power line. In addition to being supplied to the equipment, the power for driving the electronic circuit is supplied to an electronic circuit for controlling the driving of the equipment mounted on the vehicle via a power supply line for small current. On the other hand, for example, when a short circuit to the body occurs at a certain point on the main power supply line, the small current power supply line is shorted 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 cutoff means is switched to the cutoff state. Further, in response to this switching, the second connection blocking means also switches to the blocking state. As a result, the connection between the power supply and the vehicle-mounted equipment via the main power supply line is cut off, and it is possible to avoid an excessive current from flowing from the power supply to the short-circuited location via the main power supply line. At this time, the power supply line for small current fulfills the function of supplying power for driving the electronic circuit in addition to the function of detecting the short circuit of the main power supply line in advance.
[0012]
In the vehicular power supply device of the present invention, it is preferable that the first connection cut-off unit switches the connection state from the connection state to the cut-off state when a current flowing through the small current power line exceeds a predetermined current value. Change.
[0013]
In the vehicle power supply device according to the present invention, preferably, the first connection cutoff means is a fuse, and the second connection cutoff means detects whether or not the fuse is blown. Means, a switch, and control means for switching the switch from the closed state to the open state when the fusing detection means detects fusing.
[0014]
In the vehicular power supply device of the present invention, it is preferable that the first connection cutoff means is an intelligent power switch configured using a semiconductor.
[0015]
In the vehicular power supply apparatus of the present invention, it is preferable that the second connection cutoff means includes a relay switch.
[0016]
In the vehicular power supply device of the present invention, it is preferable that the small current power line is a line for supplying power for driving an electronic circuit.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a vehicle power supply apparatus 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, a battery 43 and a power supply unit 32 are connected via a main power supply line 28, and the power supply unit 32 and the power supplied part 33 connect the main power supply line 41. The power supply unit 33 and the load 50 are connected via the main power line 42. Here, the main power supply line 41 is incorporated in the power supply line 51 together with the power supply line 29 for small current.
[0018]
In the power supply unit 32, one end of the fuse 19, the switch 35 a of the power cutoff unit 35, and one end of the coil 35 b are connected in parallel to the positive electrode of the battery 43 via the main power line 28. The positive electrode of the battery 43 is further connected to the fuse blow monitoring unit 36 and the electronic component power circuit 34. In addition, the positive electrode of the battery 43 is connected to the output of the alternator ALT, and the alternator ALT supplies power to the load and the control unit connected to the positive electrode of the battery 43 at the time of engine rotation. The battery 43 is configured to be charged.
[0019]
The other end of the fuse 19 is connected to one end of a power supply line 39 for small current. The other end of the small current power line 39 is connected to the small current power line 49 via the small current power line 29. Here, the small current power supply lines 39, 29, and 49 supply driving power for backing up the memory and driving the electronic circuit from the battery 43 to the electronic component power supply circuit 44, and the current capacity is 10A. The current capacity of the main power supply lines 28, 41, 42 is smaller than that of 50 to 100A. Further, as the fuse 19, for example, a small capacity fuse that blows with a current of 10 A or less is used. Both ends of the fuse 19 are also connected to the fuse blow monitoring unit 36. The fuse blow monitoring unit 36 detects whether or not the fuse 19 is blown by the potential monitoring means on the downstream side of the fuse, and outputs the detection result to the logic circuit 37.
[0020]
The other end of the switch 35 a is connected to one end of the main power supply line 41. The other end of the coil 35 b is connected to the logic circuit 37 via the inverter 38. The electronic component power circuit 34 is also connected to a logic circuit 37. The electronic component power supply circuit 34 converts the 12V power supply voltage supplied from the main power supply line 28 into a 5V electronic circuit drive voltage by DC-DC conversion, 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 blow monitoring unit 36 indicates that the fuse is blown, the logic circuit 37 demagnetizes the coil 35b via the inverter 38 and opens the switch 35a. On the other hand, when the detection result S19 from the fuse blow monitoring unit 36 indicates that the fuse has not blown, the coil 35b is excited via the inverter 38 and the switch 35a is closed.
[0021]
In the power supplied part 33, the main power supply line 41 is connected to one end of the switch 45a and the coil 45b in the power cutoff part 45. The other end of the switch 45a is connected to the load 50 via the main power line 42. The other end of the coil 45 b is connected to the logic circuit 47 via the inverter 48. Further, the other end of the small current power line 49 is connected to the electronic component power circuit 44, and the electronic component power 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.
[0022]
FIG. 2 is an internal configuration diagram of the power supply line 51. As shown in FIG. 2, the power supply line 51 covers the periphery of the main power supply line 41 that is a central conductor with an insulator 52 such as PVC, and the insulator 52 surrounds the power supply line 29 for small current such as an ECU power supply. And the resin 53 is further coated on the periphery.
[0023]
Hereinafter, the function of the vehicle power supply device 31 will be described. When there is no abnormality in the power supply line 51, as shown in FIG. 1, the logic circuits 37 and 47 demagnetize the coils 35b and 45b via the inverters 38 and 48, respectively, and the switches 35a and 45a are opened. It is in a state. Therefore, when the coil 45b is excited by the logic circuit 47 and the switch 45a is in the closed state, the power supply current from the battery 43 is supplied from the main power supply line 28, the power supply cutoff unit 35, the main power supply line 41, and the power supply cutoff unit 45. And is supplied to the load 50 via the main power line 42. In addition, an electronic component driving current is supplied from the main power supply line 28 to the electronic component power supply circuit 44 through the fuse 19, the small current power supply line 39 and the small current power supply line 29.
[0024]
By the way, for example, when 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 prior to that. , 29 and 49, excessive current flows. Therefore, the fuse 19 is blown and the blow is detected by the fuse blow monitoring unit 36. At this time, since the fuse 19 having a small capacity of 10 A or less is used, it is possible to sense an intermittent short circuit (rare short) sensitively and to blow the fuse 19.
[0025]
Then, a detection result S19 indicating that the fuse has been blown is output from the fuse blow monitoring unit 36 to the logic circuit 37. When this 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 are in a non-conductive state, and no abnormal current flows through the main power supply line 41 even if the main power supply line 41 is short-circuited. 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.
[0026]
As described above, according to the vehicle power supply device 31, by monitoring the fusing of the fuse 19 connected to the small current power supply line 29, a short circuit of the main power supply line 41 is detected in advance, and the short circuit location is detected. Can be separated. In addition, according to the vehicle power supply device 31, the small current power supply line 29 has a function of supplying power for driving electronic components in addition to the short-circuit monitoring function. Can be configured.
[0027]
In the vehicle power supply device 31, as shown in FIG. 4, the power supply line 51 covers the periphery of the main power supply line 41, which is a central conductor, with an insulator 52 such as PVC. The current power supply line 29 may be wound in a spiral shape and the periphery thereof may be further covered with a resin 53.
[0028]
Second embodiment
FIG. 5 is a configuration diagram of the vehicle power supply device 81 according to the present embodiment. In FIG. 5, the same components as those in 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 Switch) 61 and a logic circuit 67 are connected to the main power supply line 28 in the power supply unit 62. The IPS 61 and the logic circuit 77 of the power supply unit 63 are connected via a power supply line 71 for small current. The switch 35 a of the power shut-off unit 35 and the switch 45 a of the power shut-off unit 45 are connected via the main power line 72. In addition, 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 connected to the outer periphery of the main power supply line 72 via an insulating layer, for example, similarly to the power supply line 51 shown in FIG. It is formed by winding and is incorporated in one power supply line 78.
[0029]
The IPS 61 monitors the current flowing through the small current power line 71 and determines that the current flows through the small current power line 71 by judging that the current flows abnormally even in the overcurrent or the rated current. It is composed of elements. 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 illustrated in FIG. 6, the IPS 61 includes an input logic 200 that inputs an IPS drive signal S67a from a logic circuit 67, a drive circuit 201, and an output circuit 202, for example. Depending on the output of the output circuit 202, the power supply to the small current power supply line 71 is driven or stopped. The IPS 61 is provided with a protection circuit 203 and a diagnostic circuit 204. The protection circuit 203 protects an electronic circuit and the like in the IPS 61 from an excessive current and an excessive voltage. The diagnostic circuit 204 diagnoses the internal circuit state. For an actual product of IPS 61, refer to TPD1004S manufactured by Toshiba, for example. The IPS 61 receives the IPS drive signal S67a from the logic circuit 67. The IPS 61 is driven when the IPS drive signal S67a is at a high level, and is stopped when the IPS drive signal S67a is at a low level. The IPS 61 may monitor heat generation and cut off the current.
[0030]
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, a multiplex transmission circuit 84, and a bus interface circuit 85. The DC-DC converter 82 converts the 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 driven by the electronic circuit driving voltage from the DC-DC converter 82 and, as will be described later, when the pulse generated in the IPS abnormality signal S61 is detected, the coil 35b is demagnetized via the inverter 38, and the switch Open 35a. The microcomputer 83 outputs a multiplexed signal to the logic circuit 77 via the multiplex transmission circuit 84, the bus interface circuit 85, and the multiplex transmission line 73.
[0031]
Hereinafter, the operation of the vehicle power supply device 81 will be described with reference to FIGS. FIG. 8 is a timing chart of the potential of each signal and line when damage occurs at point a of the power supply line 78 shown in FIG. 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, and as shown in FIG. 8C, the potential of the small current power supply line 71 at time t1. Decreases, and an excessive current flows through the power supply line 71 for small current. This excess current is detected in the IPS 61, and as shown in FIG. 8D, a pulse is generated in the IPS abnormality signal S61 at time t2. 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 the high level to the low level at time t3. As a result, the IPS 61 maintains the state where the main power line 28 and the small current power line 71 are cut off, the coil 35b of the power cut-off unit 35 is demagnetized, the switch 35a is opened, and the main power line 72 is turned off. The potential switches from high level to low level.
[0032]
As described above, according to the vehicle power supply device 81, based on the detection result from the IPS 61 connected to the small current power supply line 71, the short circuit of the main power supply line 71 is detected in advance, and the short circuit location is determined. 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 driving current for electronic components in addition to the short-circuit monitoring function. Can be configured.
[0033]
Third embodiment
FIG. 9 is a configuration diagram of the vehicle power supply device 91 according to the present embodiment. As shown in FIG. 9, a terminal 110 composed of a multiplex transmission circuit 92, a control circuit 93, and a bus interface 94 is arranged on the left side of the multiplex transmission lines 96 and 97 in the drawing. In addition, a terminal 111 including a multiplex transmission circuit 102, a control circuit 103, and a bus interface 104 is disposed on the right side in the drawing with respect to the multiplex transmission lines 96 and 97. 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 via a transmission line Tx and a reception line Rx. It is connected. Further, the bus interface 94 and the control circuit 93 are connected via an abnormal signal line 99.
[0034]
Although not shown in FIG. 9, in addition to the multiplex transmission lines 96 and 97, as shown in FIG. 10, a main power supply line 112 and a circuit drive power supply line 113 are provided between the terminal 110 and the terminal 111. Arranged. These lines are incorporated in the wire harness 115 by covering both the main power supply line 112 and the circuit drive power supply line 113 with multiple transmission lines 96 and 97 positioned in parallel and covering with a protective layer 114. By the way, the multiplex transmission lines 96 and 97 may be incorporated in the wire harness 115 so as to constitute a twisted pair wire. Thus, as will be described later using the multiplex transmission line 96 and the multiplex transmission line 97, it is possible to suppress the influence of the common mode noise generated during the transmission by transmitting substantially the same signals whose levels are mutually inverted. At the same time, even if one multiplex transmission line is short-circuited, a signal can be transmitted through the other multiplex transmission line.
[0035]
The multiplex transmission circuit 92 converts the parallel signal input from the control circuit 93 through the data transmission line 95 into a time-division serial signal as shown in FIG. 11A, and the serial signal is transmitted through the transmission line Tx. To the bus interface 94. In this serial signal, the first 2 bits indicate the start of the data body, and the subsequent 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 set to the high level, the second phase is set to the low level or the high level according to the data value, and the third phase PWM (Pulse Width Modulation) is used in which is always at a low level.
[0036]
FIG. 12 is a configuration diagram of the bus interface 94. Note that the bus interface 104 of the terminal 111 has the same configuration as the bus interface 94. As shown in FIG. 12, the bus interface 94 includes a transmission circuit 94a, a reception circuit 94b, and a reception circuit 94c. In the transmission circuit 94 a, the transmission line Tx is connected to the current source 121 and is also connected to the current source 122 via the inverter 120. Accordingly, a voltage corresponding to the level of the transmission line Tx is applied to the current source 121, and a voltage corresponding to a level obtained by inverting the level of the transmission line Tx is applied to the current source 122.
[0037]
The current sources 121 and 122 output currents proportional to the applied voltage to the transmission lines 123 and 124, respectively. Here, the transmission line 123 is connected to the ground via a resistor 136, and the transmission line 124 is connected to a power supply voltage via a resistor 135. When the time-division serial signal shown in FIG. 11A 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. Due to the bias function of the resistor 136, the potentials of the transmission line 123 and the multiple transmission line 96 become as shown in FIG. 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 biased by the bias function of the resistor 135. Is as shown in FIG.
[0038]
In the receiving circuit 94 b, the transmission line 123 is connected to one input terminal of the pulse level setting circuit 129 via the capacitor 125, and its output terminal is connected to the + input terminal of the comparator 131. The transmission line 124 is connected to the other input terminal of the pulse level setting circuit 129 via the capacitor 126, and its 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 an exclusive OR (XOR) circuit 133. Here, even if a failure such as a short circuit occurs in one of the multiplex transmission lines 96 and 97, the receiving circuit 94b discriminates the received signal received through the other multiplex transmission line and receives the received signal. The level of the received signal is set in the pulse level setting circuit 129 so as to be output to the multiplex transmission circuit 92 via the line Rx. 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 it to the control circuit 93 via the data transmission line 95.
[0039]
Further, in the receiving circuit 94 c, the transmission line 123 is connected to one input terminal of the pulse level setting circuit 130 via the capacitor 127, and its output terminal is connected to the + input terminal of the comparator 132. Further, the transmission line 124 is connected to the other input terminal of the pulse level setting circuit 130 via the capacitor 128, and its output terminal is connected to the negative input terminal of the comparator 132. The comparator 132 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 other input terminal of the exclusive OR circuit 133. Here, the receiving circuit 94c sets the level of the received signal in the pulse level setting circuit 130 so that the received signal cannot be discriminated unless an accurate received signal is received from both of the multiplex transmission lines 96 and 97.
[0040]
The exclusive OR circuit 133 inputs the received signal from the output terminals of both the comparator 131 and the comparator 132, calculates the exclusive OR, and controls the operation result as an abnormal signal via the abnormal signal line 99. Output to the 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.
[0041]
The operation when the multiplex transmission line 97 interferes with the body at the point a and is short-circuited to the ground in the vehicle power supply device 91 shown in FIG. 9 will be described below. FIG. 13 is a waveform diagram of each signal of the vehicle signal transmission device 91 when the multiplex transmission line 97 is short-circuited at the point a. Note that the short circuit of the multiplex transmission lines 96 and 97 usually occurs prior to the short circuit of the main power supply line 112 and the circuit drive power supply line 113 due to the structure of the wire harness 115 shown in FIG. When the point a on the multiplex transmission line 96 is short-circuited at time t1 shown in FIG. 13, the waveforms of the potentials 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 as shown in FIG. 13 (A) and (B). At this time, in the reception circuit corresponding to the reception circuit 94b shown in FIG. 12 based on the transmission signal S97 received via the multiplex transmission line 97 in the bus interface 104 of the terminal 111, the reception shown in FIG. A signal SRx is generated, and this reception signal SRx is output to the multiplex transmission circuit 102 via the reception line Rx.
[0042]
On the other hand, the abnormal signal S150 generated in the receiving circuit corresponding to the receiving circuit 94c shown in FIG. 12 is switched from the high level to the low level at time t1, as shown in FIG. When the control circuit 103 detects that the abnormal signal S150 input from the receiving circuit 94c is switched from the high level to the low level, the control circuit 103 switches the relay drive signal from the high level to the low level as shown in FIG. . This relay drive signal is output from the control circuit 103 to a relay switch (not shown) provided on the main power supply line 112 shown in FIG. This relay switch is switched from the connected state to the cut-off state when the relay drive signal is switched from the high level to the low level. As a result, the potential of the main power supply line 112 drops from 12V to 0V as shown in FIG. A relay switch may also be provided on the circuit drive power supply line 113 shown in FIG. 10, and this relay switch may be cut off based on a relay drive signal from the control circuit 103.
[0043]
By the way, when both of the multiple transmission lines 96 and 97 are simultaneously short-circuited at the point a shown in FIG. 9, the bus interface 104 does not receive any transmission signal. The control circuit 103 switches the relay drive signal from the high level to the low level and shuts off the main power supply line 112 when the bus interface 104 does not receive the transmission signal for a certain period of time. For example, when the communication cycle is 50 ms and the control circuit 103 does not receive a transmission signal for 100 ms, the control circuit 103 switches the relay drive signal from a high level to a low level.
[0044]
As described above, according to the vehicle power supply device 91, based on the reception result received by the terminal 111 via the multiple transmission lines 96 and 97, the main power supply line 112 and the circuit drive power supply line shown in FIG. It is possible to detect the short circuit 113 in advance and to disconnect the short circuit portion. 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, so that a simple system configuration without waste can be achieved.
[0045]
The present invention is not limited to the embodiment described above. For example, in the above-described embodiment, the power supply unit and the power supply unit and the data communication between two terminals are illustrated, but a single power supply unit and a plurality of power supply units are connected. The present invention can also be applied when there are three or more terminals connected in a many-to-many or one-to-many manner.
[0046]
Further, in the above-described embodiment, the fuse and the IPS are exemplified as the first connection cutoff unit. However, if the abnormality is detected in the power supply line for small current and the connection is cut off, other connection cutoff units are used. It may be used.
[0047]
【The invention's effect】
As described above, according to the vehicle power supply device, the connection between the power supply via the main power supply line and the equipment mounted on the vehicle is interrupted before the main power supply line fails, and the power supply via the main power supply line is interrupted. Therefore, it is possible to avoid an excessive current from flowing to the fault location. Moreover, according to the vehicle power supply device of the present invention,The power line for small current is a short circuit of the main power lineIn addition to the function of detecting the power in advance, the function of supplying power for driving the electronic circuit and the function of signal transmission are fulfilled, and a simple and lean system configuration can be achieved.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a vehicle power supply device according to a first embodiment of the present invention in a normal state.
FIG. 2 is an internal configuration diagram of a power supply line shown in FIG. 1;
FIG. 3 is a configuration diagram when the vehicular power supply device shown in FIG. 1 enters 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 block diagram of an IPS.
FIG. 7 is a configuration diagram of the logic circuit shown in FIG. 5;
8 is a timing chart of signals and line potentials when damage occurs at point a of the power supply line shown in FIG. 5; FIG.
FIG. 9 is a configuration diagram of a vehicle power supply device according to a third embodiment of the present invention.
10 is a view for explaining the 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 the transmission line Tx, FIG. 11B is a waveform diagram of a current flowing through the first transmission line, and FIG. 11C is a waveform flowing through the second transmission line. It is a waveform diagram of current.
FIG. 12 is a block diagram of the bus interface shown in FIG. 9;
13 is a waveform diagram of each signal and line when the first multiplex transmission line is short-circuited at a 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 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 electric 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 electric 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 section
33, 63 ... Power supply section
41, 72 ... main power line
43 ... Battery
35, 45 ... Power shut-off section
50 ... load
51 ... Power line
73. Multiple transmission lines
96, 97 ... Multiple transmission lines
110, 111 ... terminal

Claims (6)

Power supply,
A main power line for electrically connecting the on-vehicle equipment driven by the power source;
One or a plurality of power supply lines for small current, which are arranged near the main power supply line or via an insulating layer, and have a smaller current capacity than the main power supply line,
A first connection disconnecting means which is provided at a predetermined position on the small current power line, and disconnects the connection when an abnormal current flows through the small current power line;
A second connection blocking means provided at a predetermined position on the main power supply line, wherein the first connection blocking means switches from the connected state to the blocked state in conjunction with the switching from the connected state to the blocked state; A power supply device for a vehicle. 2. The vehicle power supply device according to claim 1, wherein the first connection cut-off unit switches from a connected state to a cut-off state when a current flowing through the small current power line exceeds a predetermined current value. The first connection blocking means is a fuse;
The second connection cut-off means includes a fusing detection means for detecting whether or not the fuse is blown, a switch, and a control for switching the switch from a closed state to an open state when the fusing detection means detects a fusing. The vehicle power supply device according to claim 2, further comprising: means. The vehicle power supply device according to claim 1, wherein the first connection cutoff means is an intelligent power switch configured using a semiconductor. The vehicular power supply device according to any one of claims 1 to 4, wherein the second connection blocking means includes a relay switch. The vehicle power supply device according to claim 1, wherein the small current power supply line is a line that supplies power for driving an electronic circuit.

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