JP2881527B2 - Electrical component protection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a power supply device of an automobile. INDUSTRIAL APPLICABILITY The present invention is applied to a power supply device equipped with a relay switch at a battery terminal and configured to disconnect the battery from a circuit by the relay switch when the vehicle is stopped and the battery is not used.

[0002]

2. Description of the Related Art When an automobile is stopped and an engine is stopped and accessories such as a radio and a room light are not used, a battery terminal is disconnected from various circuits to prevent a slight discharge current from being generated and protect the battery. A power supply device for performing the operation is known. Such a device is often mounted on a large vehicle, and the switch is manually operated after getting out of the vehicle. However, since recent manual operations are troublesome, an open / close relay switch provided between the battery terminal and the terminal to which the electrical component and the charging circuit are connected in conjunction with the operation of the key switch in the driver's seat. The structure which is performed by opening the door has become widespread.

[0003] When the open / close type relay switch is opened due to some abnormal cause while the engine is running even while the vehicle is running or stopped, the battery is electrically disconnected from the electric components and the charging circuit of the vehicle. I will be. When the battery is disconnected, the current generated by the charging circuit flows directly into the electrical components, and the engine does not stop immediately.However, there are disadvantages such as abnormal voltage applied to the electrical components. Will happen.

In the conventional device, the open / close type relay switch is opened due to some abnormal cause during the rotation of the engine, and the battery is rotated in conjunction with the engine so as not to be disconnected from the circuit. The voltage of the neutral point of the generator is detected, and when the voltage is output, it is determined that the engine is rotating. When the voltage of the neutral point is equal to or higher than a predetermined value, the relay switch is opened. A circuit is provided for holding the exciting current of the relay switch so as not to be in a state.

[0005]

However, although this is a very rare abnormal phenomenon, when the regulator of the charging circuit is abnormal, the voltage at the neutral point of the generator is reduced despite the fact that the engine is rotating. There was sometimes. This can occur when the wire is disconnected, the connector is disconnected, or the driver accidentally turns off the relay switch. When a regulator abnormality occurs, the output terminal voltage of the charging circuit may rise abnormally. At that time, when the battery is disconnected from the circuit, the output of the charging circuit is directly applied to various electric components of the vehicle. The electrical components for current large vehicles have a power supply voltage increased by about 30% with respect to a power supply rated voltage of 24 V.
Although it is not destroyed up to about V, if it exceeds this, electrical components may be damaged, and even if the charging circuit is repaired, the failure may not be easily recovered.

The present invention has been made in such a background. When an abnormally high voltage is present at a terminal of a charging circuit or a terminal of an electrical component, a relay for disconnecting a battery terminal regardless of the cause. An object of the present invention is to provide a protection circuit connected to a relay switch so that the switch does not open. That is, according to the present invention, the relay switch for disconnecting the battery terminal from the circuit is opened due to an abnormal phenomenon of the circuit, and the high voltage generated in the charging circuit is applied to the electric component without being absorbed by the battery, and It is an object of the present invention to provide a circuit for preventing the device from being damaged.

[0007]

According to the present invention, a contact is provided in parallel with an open / close switch for controlling an open / close type relay switch provided between a battery terminal and a terminal to which electrical components and a charging circuit are connected. Connected to the relay in the closed state
An open / close type protection relay for controlling a switch to a closed state, a detection circuit for detecting that a voltage of a terminal connected to the electrical component and the charging circuit exceeds a reference value, and an output of the detection circuit, the protection relay And a relay drive circuit for controlling the switch to a closed state.

[0008]

The voltage of the terminal to which the electrical component and the charging circuit are connected is equal to the reference value (for example, 32
If the voltage exceeds V), the electrical components may be damaged due to the power supply voltage being too high. When the reference value is exceeded, this is detected and the excitation current of the relay switch for disconnecting the battery from the circuit is forcibly applied. It is controlled so that it is continuously maintained.

That is, a protection relay is connected in parallel with an on / off switch for controlling the relay switch, and when the voltage of a terminal connected to an electrical component and a charging circuit exceeds a reference value, the protection relay is forcibly turned off. To prevent the battery from being disconnected from the circuit.

Since the internal resistance of the battery is low, even if an abnormally high voltage is applied to the terminal from the charging circuit, the battery absorbs the voltage, and the influence does not spread to various electric components.

This protection relay uses a self-holding type relay. Once activated, an alarm is displayed on the driver's seat to warn the driver, and the protection relay must be reset only by manual operation. Is desirable for safety.

Thus, even if an abnormality occurs in the regulator of the charging circuit and the output voltage of the charging circuit rises,
The influence can be prevented from spreading to the electrical components.

[0013]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing the overall configuration according to the embodiment of the present invention, and FIG. 2 is a circuit diagram showing the configuration of the embodiment of the present invention.

In the embodiment of the present invention, an open / close switch 5 for controlling an open / close relay switch 4 provided between a terminal of a battery 1 and a terminal to which an electric component 2 and a charging circuit 3 are connected is provided with a contact thereof. An open / close protection relay 6 connected in parallel, a detection circuit 7 for detecting that the voltage of the terminal to which the electrical component 2 and the charging circuit 3 are connected exceeds a reference value,
A relay drive circuit for controlling the protection relay to be closed by the output of the detection circuit;

The charging circuit 3 includes a generator and a regulator, and the protection relay 6 is provided with an alarm switch 9 for displaying an alarm on an alarm indicator 10 provided in the driver's seat so as to be linked and closed. .

Next, the operation of the embodiment of the present invention configured as described above will be described.

In a normal operation state, when the open / close switch 5 is operated and closed, a current is supplied from the battery 1 to the coil of the relay switch 4 to close the contact, and the battery 1 is closed.
Are electrically connected to the electrical component 2 and the charging circuit 3. As a result, a charging current is supplied from the charging circuit 3 to the battery 1, and a load current is supplied from the battery 1 to the electrical component 2.

When the vehicle stops and the engine is stopped and the open / close switch 5 is opened, the current supply to the coil of the relay switch 4 is stopped, the contacts are opened, and the connection between the battery 1 and the electrical components 2 and the charging circuit 3 is established. The electrical connection is open. Although the electrical component 2 and the charging circuit 3 remain electrically connected, the engine is stopped.
No current is supplied from the charging circuit 3 to the electrical component 2.

However, as a very rare abnormal phenomenon, an abnormality occurs in the regulator of the charging circuit and the output terminal voltage rises abnormally, or the generator in the charging circuit 3 despite the rotation of the engine. When the voltage at the neutral point decreases, the relay switch 4 is opened, the connection between the battery 1 and the charging circuit 3 is disconnected, and the output from the charging circuit 3 is directly applied to the electrical component 2. is there.

When such a state occurs, the charging circuit 3
Is applied to the detection circuit 7. Detection circuit 7
Compares the output voltage and the reference voltage V _CC applied, and sends the detection output to the relay driving circuit 8 when it detects a that exceeds the value of the reference voltage. Upon receiving this detection output, the relay drive circuit 8 forms a circuit in which a current is supplied from the battery 1 to the coil of the protection relay 6 and closes the contact.

When the contact of the protection relay 6 is closed, the current from the battery 1 excites the coil of the relay switch 4 to close the contact, and the battery 1 and the charging circuit 3 are electrically connected. The high voltage generated by the charging circuit 3 is absorbed by the battery 1 via the contact point of the relay switch 4 and reliably prevents the electrical component 2 from being damaged by directly applying the high voltage. At this time, the alarm switch 9 is closed in conjunction with the operation of the protection relay 6, and an alarm is displayed on an alarm display 10 provided in the driver's seat to notify the occurrence of an abnormality.

As the protection relay 6, a self-holding type relay is used, and when activated once, an alarm is displayed as described above, and the closed state of the contact is maintained until the contact is manually reset to maintain safety. .

[0023]

As described above, according to the present invention, the battery terminal and the electric component and the charging circuit are connected between the battery terminal and the terminal to which the electric component is connected for some reason while the engine is operating. When the relay switch is opened, the abnormal voltage from the charging circuit is detected and an alarm is automatically displayed, and the relay switch is closed to prevent the abnormal voltage from being applied to the electrical components and damage them. There is an effect that can be prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an overall configuration according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery 2 Electrical component 3 Charging circuit 4 Relay switch 5 Open / close switch 6 Protection relay 7 Detection circuit 8 Relay drive circuit 9 Alarm switch 10 Alarm display

Claims (1)

(57) [Claims] An open / close switch for controlling an open / close type relay switch provided between a battery terminal and a terminal to which an electrical component and a charging circuit are connected has its contact connected in parallel and the relay is closed. Control the switch to the closed state
An open / close type protection relay, a detection circuit for detecting that a voltage of a terminal connected to the electrical component and the charging circuit exceeds a reference value, and controlling the protection relay to a closed state by an output of the detection circuit. An electrical component protection circuit comprising a relay drive circuit.