JPS63170146A - Load control unit for automobile - Google Patents

Abstract

PURPOSE:To keep off any malfunction of load due to a noise, by connecting each of control units thereto at each load, giving a common signal and a separate signal to each control unit, and operating the load conformed to the control unit to which pulses of both these signal are given. CONSTITUTION:Each of control units 7 are installed at each load 22 of an automobile, and each control unit 7 is made up of unitizing a voltage regulator circuit 13, a latch circuit 14, a switch circuit 15 and a current detector 16 in a body. And, a common signal line 23 out of a microcomputer is connected to a signal terminal SIG of each control unit 7 and a separate address signal line 24 to an address terminal AD, respectively, thereby making a signal so as to be given to a data terminal D of the latch circuit 14 and an address signal to a clock terminal CL respectively. And, control takes place so as to performed current-energization to the load 22 conformed to the control unit 7 to which the signal and the address of the latch circuit 14 are given at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automobile load control device for controlling loads of an automobile such as headlamps, turn signal lamps, wiper motors, and the like.

(Prior Art) Conventionally, it has been considered to control electrical loads installed in automobiles, such as headlamps and turn signals, using signals output from a microcomputer. and,
The driver is controlled by signals from the microcomputer, and the load is controlled by this driver.

(Problems to be Solved by the Invention) By the way, in the interior of a car, there is strong noise such as ignition noise.

For this reason, conventional load control devices for automobiles using microcomputers have a problem in that noise is superimposed on signals from the microcomputer, which tends to cause malfunctions of the load. Further, since the conventional device does not have a failure diagnosis function for each load, there is a problem in that a fuse is interposed in the power supply line for each load, and the arrangement and wiring of the fuse for that purpose is complicated.

An object of the present invention has been made to solve the above-mentioned problems of the conventional load control device for automobiles, and is a load control device for automobiles that does not cause load malfunctions due to noise and has a failure diagnosis function for each load. The goal is to provide equipment.

(Means for solving the problem) In order to achieve the above object, the automobile load control device of the present invention connects control units in series for each load of the automobile, and connects these control units with a switch circuit. The control circuit is provided with a control circuit and a current detection circuit, and a microcomputer applies a common signal signal to the plurality of control units as well as individual address signals, and pulses of the signal signal and the address signal are applied simultaneously to the control circuit. only closes the switch circuit to supply power to the corresponding load, and then when a pulse of the address signal is applied, the control circuit opens the switch circuit to cut off power to the load; Further, the current detection circuit is configured to provide a fault signal to the microcomputer when the current flowing when the switch circuit is closed is outside a predetermined range.

(Function) A control unit is connected in series for each load of an automobile, and a microcomputer gives a common signal signal to these multiple control units, as well as individual address signals, so that the pulses of the signal signal and address signal are simultaneously generated. Since power is supplied to the load corresponding to a given control unit, even if noise is superimposed on either the signal signal or the address signal, it will not be superimposed on the signal signal unless it is superimposed on both signals. Noise and the address signal, or noise superimposed on the address signal and pulses of the signal signal are not applied to the control unit at the same time, and a malfunction in which power is supplied to the load due to noise does not occur. In addition, we installed a current detection circuit in the control unit to give a fault signal to the microcomputer when the current flowing through the load is outside a predetermined range, so the microcomputer can recognize a fault based on this fault signal. .

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is a block circuit diagram of an embodiment of a load control device for an automobile according to the present invention, and FIG. 2 is a time chart for explaining the operation of FIG. 1 when the load is normal. , FIG. 3 is a time chart for explaining the operation shown in FIG. 1 when a load fails, and FIG. 4 is a perspective view of an example of the control unit shown in FIG. 1 and the power supply line connecting it. FIG. 5 is a schematic diagram in which the automobile load control device of FIG. 1 is mounted on an automobile.

In FIGS. 1, 4, and 5, the structure will first be explained. A power supply line 4 is constructed by integrally molding a pair of conductive members 1.2, which are made of a band plate of a material that conducts vehicle weight such as copper and has good heat conductivity, with an insulating material 3 in an insulated state. This power supply line 4 is appropriately wired inside the vehicle 5, one conductive member 1 is electrically connected to the positive terminal of the vehicle battery 6, and the other conductive member 2 is electrically connected to the negative terminal of the vehicle battery 6. Connected. The power supply line 4 is also configured with a plurality of connection openings 8.8- to which the control unit 7.7- can be connected. The connection openings 8.8 and 8.-- are connected to the lids 9, 9, which can be opened and closed as appropriate, for example.
-, a part of the pair of conductive members 1.2 is exposed in the opening, and a fixing member 10 of the control unit 7.7-
．． 10- is provided. Further, a signal line storage duct 11 having a C-shaped cross section is integrally formed along the power line 4.
is provided, and an outlet 12 for power supply is also provided. It should be noted that if the power line 4 is connected in sequence with appropriate lengths and wired appropriately inside the vehicle 5,
It is possible to wire different automobiles 5 using common parts.

The control unit 7.7.- is the voltage regulator circuit 13.
A switch circuit including a latch circuit 14 which is a control circuit, and switching elements such as MOSFET! 5 and a current detection circuit 16 are included as a unit, and a resistor 17 is provided externally. The control unit 7.7- is fixed to the power supply line 4 with screws 18.18-, and the conductive member 1 has the switch circuit 15 and the like exposed.
．． 2. In addition, the signal line storage duct U
It is connected to an on-vehicle microcomputer 20 by a signal line bundle 19 housed in the . In addition, the control unit
7- is the load 22.22 through the joint 21.21-
connected to.

Next, the structure of the control unit 7.7- will be specifically explained. One conductive member 1 serving as a power supply line is connected to power input terminals v and H, and this power input terminal VIN is connected to one end of a voltage regulator circuit 13 and a load 22. Further, the other conductive member 2 serving as a ground line is connected to a ground terminal GND, and this ground terminal GND is connected to a current detection circuit 16 and a switch circuit 15 via a resistor 17.
connected to one terminal of the Note that the other terminal of the switch circuit 15 is connected to the other end of the load 22. A signal line 23 from the microcomputer 20 is commonly connected to the signal terminal SIG of the plurality of control units 7.7.-, and a signal signal is applied to the data terminal of each latch circuit 14.14. Further, separate address signal lines 24.24- from the microcomputer 20 to each control unit 7.7.
7-, and an address signal is applied to the clock terminal CL of each latch circuit 14, 14-. Furthermore, the output end of the current detection circuit 16 is connected to a fault signal output terminal FAIL, which is connected to the microcomputer 20 via a fault signal line 25°25.- for each control unit 7.7-. A fault signal is given to the microcomputer 20 from the control unit 7.7-. Then, the voltage adjusted to a predetermined value by the voltage regulator circuit 13 is supplied to the latch circuit 14 as a driving voltage, and the switch circuit 15 is controlled by the output of the latch circuit 14. At some point, the current detection circuit 16 outputs a fault signal.

The operation of the control unit 7.7- with such a configuration will be explained with reference to FIGS. 2 and 3. microcomputer 2
From address signal line 24, 24, . Also,
As shown in FIG. 2(b), a common signal signal in which a plurality of pulses are arranged in series indicating the timing of supplying power to each load 22, 22, . 7- is given. When the latch circuit 14 receives pulses of the address signal and the signal signal simultaneously, it closes the switch circuit 15 as shown in FIG. 2(C) and supplies power to the corresponding load 22. If the load is normal at this time, switch circuit 1
Due to the current flowing through 5, there is a resistance as shown in Figure 2 (d)! Although there is a slight potential difference between both ends of the circuit 7, it is within a predetermined range, and the current detection circuit 16 does not output a failure signal as shown in FIG. 2(e). When the primary address signal pulse is applied, the latch circuit 14 opens the switch circuit 15 and loads the load 2.
Cut off the power to 2.

By the way, as described above, when power is supplied to the load 22, if the load 22 is short-circuited, a large current flows through the switch circuit 15, and the potential difference d across the resistor 17 increases as shown in FIG. 3(d). exceeds a predetermined range, the current detection circuit 16 detects this and outputs a failure signal to the microcomputer 20 as shown in FIG. 3(e). Furthermore, if the load 22 is in an open state when power is supplied to the load 22, no current flows through the switch circuit 15, and the potential difference d0 across the resistor 17 becomes zero as shown in FIG. 3(d). Therefore, the current detection circuit 16 detects the potential difference d across the resistor 17.

When it detects that is below a predetermined range, it outputs a failure signal as shown in FIG. 3(e).

Microcomputer 2 given these fault signals
0 indicates the failure by lighting an alarm lamp or the like as appropriate, and thereafter stops outputting the address signal to the control unit 7 to which the failed load 22 is connected.

In the above embodiment, one control unit 7 is arranged for one load 22, but in consideration of the current capacity of the switch circuit 15, a plurality of control units 7 are arranged in parallel for one load 22. You can also connect.

By connecting the control units 7 in parallel in this way, common parts can be used for loads 22 having different capacities.

(Effects of the Invention) As explained above, according to the load control device for an automobile of the present invention, there is no risk of malfunctions such as power being supplied to the load due to noise, and a failure of the load is detected by the control unit. Since the control unit can stop the power supply to the failed load, there is no need for a fuse like in the past.
This provides an excellent effect in that the trouble of arranging fuses, wiring, etc. can be saved.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment of a load control device for an automobile according to the present invention, and FIG. 2 is a time chart for explaining the operation of FIG. 1 when the load is normal. , FIG. 3 is a time chart for explaining the operation shown in FIG. 1 when a load fails, and FIG. 4 is a perspective view of an example of the control unit shown in FIG. 1 and the power supply line connecting it. FIG. 5 is a schematic diagram in which the automobile load control device of FIG. 1 is mounted on an automobile. 5: Automobile, 7: Control unit, 14: Latch circuit, 15: Switch circuit, 16: Current detection circuit, 17: Resistor, 20: Microcomputer, 22: Load, 23: Signal signal line, 24 Near address signal line, 25: Failure signal line.

Claims (2)

[Claims] (1) Connect a control unit in series for each load of the car,
Each of these control units is provided with a switch circuit, a control circuit, and a current detection circuit, and a microcomputer gives a common signal signal to the plurality of control units as well as individual address signals, and pulses of the signal signal and the address signal are provided. is applied at the same time, the control circuit closes the switch circuit to supply power to the corresponding load, and then when a pulse of the address signal is applied, the control circuit opens the switch circuit. The power supply to the load is cut off, and the current detection circuit is configured to give a failure signal to the microcomputer when the current flowing when the switch circuit is closed is outside a predetermined range. Features of automotive load control device. (2) The control circuit is configured to be a latch circuit, and the current detection circuit is configured to detect whether the current is outside a predetermined range from the voltage across a resistor connected in series with the switch circuit. A load control device for an automobile according to claim 1, characterized in that: