JP2546622Y2 - Power supply for vehicles - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a power supply device for a vehicle, which cuts off a power supply line from a power supply when a dark current exceeding an allowable standard is detected when an ignition switch of the vehicle is in an open state. It is.

[0002]

2. Description of the Related Art Conventionally, as this kind of technology, there is, for example, a technology disclosed in Japanese Utility Model Laid-Open Publication No. Sho 62-185432.
This is to shut off the connection between the battery power supply and the load when a load current exceeding the allowable standard is detected when the start switch is in the open state.

[0003]

However, in the above-mentioned prior art, all of the loads that need to be energized at all times, which must always be energized regardless of the start switch, are stopped. Therefore, for a load that needs to be constantly energized even when the load current becomes large, for example, a control unit constituted by a microcomputer, important storage contents of the memory are erased, and it becomes difficult to restart. The present invention is devised in view of the above-described problems, and keeps energizing a control unit that always needs to be energized even when the dark current becomes large, and reduces the amount of dark current to the switch means. It is an object of the present invention to provide a vehicle power supply device capable of preventing an excessive dark current and maintaining proper operation of a control unit by interrupting energization.

[0004]

According to the present invention, in order to achieve the above object, detection means for detecting a current of a signal circuit from a power supply and switch means connected via the signal circuit are connected to the power supply. A control unit for controlling a predetermined load in accordance with a voltage of the signal circuit which changes according to an operation of the switch means; and a current detected by the detection means when an ignition switch connected to a power supply is in an open state. A vehicle power supply device is provided including: a determination unit that determines that a reference has been exceeded; and a disconnection unit that disconnects the signal circuit based on the determination of the determination unit.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a power source, 2 denotes an ignition switch, and 3 denotes a constant voltage circuit which holds the voltage of the power source 1 at a constant voltage. 4 is a control unit,
For example, it is configured by a microcomputer. Switch means 5 and 6 are normally open contacts such as manual switches, responsive switches, and various sensors. Reference numeral 7 denotes a signal circuit, which is connected to the switch units 5 and 6 from the power supply 1 via the constant voltage circuit 3 and the detection unit 8 (described later). In the signal circuit 7, 7a and 7b
And 6 are resistors for controlling the current flowing through the resistors.

Reference numeral 8 denotes detection means for detecting the current of the signal circuit 7, and is constituted by, for example, a resistor. Reference numeral 9 denotes a cutoff unit that cuts off the signal circuit 7, and is composed of, for example, a transistor such as an FET. The control unit 4 has a power supply terminal Vdd connected to the power supply 1 via the constant voltage circuit 3. In addition, the control unit 4
Three input terminals IN1 to 1N5 and three output terminals OUT1
To OUT3. The first input terminal IN1 is connected to the ignition switch 2. Second input terminal IN
2 and the third input terminal IN3 are connected to a detecting means 8 composed of a resistor.
Is connected between both ends. The fourth input terminal IN4 is connected between the first switch means 5 and the resistor 7a. The fifth input terminal IN5 is connected between the second switch means 6 and the resistor 7b. The first output means OUT1 is connected to the cutoff means 9. The second output terminal OUT2 is connected to the first load 10, and the third output terminal OUT3 is connected to the second load 11.

Next, the operation of the above configuration will be described. FIG. 2 is a flowchart of a control routine when the control unit 4 is constituted by a microcomputer. When this routine is started, first, step 101 is the first input terminal IN1.
, It is determined whether the ignition switch 2 is ON. If the determination is YES, the process proceeds to step 102, where the first output OUT1 is turned ON to release the interruption of the signal circuit 7. Then, in step 103, when the first switch means 5 is in the ON operation, the voltage input from the signal circuit 7 to the fourth input terminal IN4 decreases, so that the control unit 4 controls the corresponding predetermined first load 10. I do. When the second switch 6 is ON, the second load 11 is controlled based on the voltage drop of the fifth input terminal IN5. When this step 103 is processed,
It returns to step 101.

On the other hand, if the determination in step 101 is NO, the process proceeds to step 104. Step 104 determines whether the potential difference between the signal voltage V2 input from the second input terminal IN2 and the signal voltage V3 input from the third input voltage IN3 exceeds a predetermined reference value Vx preset by the microcomputer. . If the determination is YES, the process proceeds to step 105. If the determination is NO, the process proceeds to step 10.
6 and then return to step 101. Generally, in order for the control unit 4 to reliably detect the operating state of each of the switch means 5 and 6, the signal circuit 7 has a switch ON.
Occasionally, a current of about 10 mA is flowing. When the switch means 5 or 6 is turned on, the potential difference exceeds the reference value Vx.

However, even if the switching means 5 and 6 are in the OFF state, if a trouble such as conduction between the contacts or malfunction occurs due to some factor, the operation is terminated.
A current of the order of milliamps flows, and the potential difference detected by the detecting means 8 exceeds the reference value Vx. In this case, step 104 considers that the current detected by the detecting means 8 has exceeded the preset allowable criterion,
A determination of YES is made. Accordingly, in step 105, the signal circuit 7 is cut off by the cut-off means 9 by outputting the first output terminal OUT1 OFF. However, the control unit 4 is still supplied with power from the power supply 1 in this state,
Always maintain proper operation.

If the determination in step 104 is NO,
Since an excessive dark current does not flow through the signal circuit 7, the interruption of the signal circuit 7 is released in step 106 by continuing the ON output from the first output terminal OUT1. As described above, the combination of step 101 and step 104 constitutes the determination unit 107 that determines that the current detected by the detection unit 8 has exceeded the allowable reference value when the ignition switch 2 is in the open state.

In the above embodiment, the detecting means 8 is not limited to a configuration in which the current difference is detected indirectly by detecting the potential difference, but may be a type in which the current of the signal circuit 7 is directly detected. Further, the numbers of the switch means 5 and 6 and the loads 10 and 11 are not limited to the above embodiment.

[0012]

As described in detail above, according to the configuration of the present invention, even if the dark current becomes large, the control unit which always needs to be energized maintains the current supply, and the factor of the dark current becomes large. By shutting off the power supply to the switch means, it is possible to provide a vehicle power supply device capable of preventing an excessive dark current and maintaining proper operation of the control means.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing an embodiment according to the present invention.

FIG. 2 is a flowchart illustrating a control routine of a control unit in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power supply 2 Ignition switch 4 Control part 5, 6 Switching means 7 Signal circuit 8 Detection means 9 Cutoff means 10, 11 Load 107 Judgment means

Claims (1)

(57) [Scope of request for utility model registration] A switch connected to the power supply via a detection circuit for detecting a current of the signal circuit from the power supply; and a switch connected to the power supply and corresponding to a voltage of the signal circuit changed by an operation of the switch. A control unit that controls a predetermined load; a determination unit configured to determine that a current detected by the detection unit exceeds an allowable standard when an ignition switch connected to a power supply is in an open state; And a shut-off means for shutting off the signal circuit based on the determination in (1).