JPS59158037A - Relay drive circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a relay drive circuit used in a vehicle flashing device, which flashes a lamp by opening and closing contacts of a relay, for example.

<Prior art and its problems> Conventional relay drive circuits perform constant voltage drive using the operating voltage during the ON time of the relay, which causes the coil section of the relay to heat up and the operating voltage to rise, resulting in rough Lacks reliability in heat resistance. It has drawbacks such as:

<Object of the Invention> Therefore, an object of the present invention is to suppress heat generation in the coil portion of a relay in a relay drive circuit, prevent an increase in operating voltage, and improve reliability with respect to heat resistance.

Structure and Effects of the Invention In order to achieve the above objects, a relay drive circuit according to the present invention connects one electrode to the other electrode of a first transistor, which has one electrode connected to one terminal of one battery. A second terminal connected to the other one of the battery terminals, respectively. Third
The bases of the transistors of the second . The other electrode of the third transistor is connected in common to the other end of a coil of a relay whose one end is connected to one of the battery terminals, and the first transistor is turned on.
By doing so, the above 2. Turning on both the third transistors and energizing the coil of the relay,
After this relay operates, after a certain period of time, the second Third
The present invention is characterized in that a delay circuit is provided that turns off one of the transistors to reduce the current flowing through the coil of the relay.

According to this invention, since a delay circuit is provided that reduces the current flowing through the coil of the relay after a certain period of time after the relay operates, heat generation in the coil of the relay is significantly suppressed, and the increase in operating voltage - b is eliminated, and reliability with respect to heat resistance is improved.

<Description of Embodiment> FIG. 1 shows an embodiment of a relay drive circuit according to the present invention, in which one battery terminal 1, 2 . First transistor3.
Second transistor4. 3rd transition 1 evening 5. Relay coil 6, capacitor 7.9°resistance 8. ．． 10.11.1
3. It is constituted by a load terminal 14. Load terminal 14
The first lamp 19 as shown in FIG. A lamp circuit having a second lamp 20 includes a turn signal switch 1
It is connected via an 8° hazard signal switch 21.

Next, the operation of this circuit will be explained.

Assuming that both the turn signal switch 18 and the hazard signal switch 21 are initially in the OFF state,
Since no base current flows through the first transistor 3, the first
Transistor 3 is OFF, so the second. Since the third transistor 4.degree. 5 is also OF, F, the relay coil 6 is not energized and the relay contact 15 is listening. Now turn the turn signal switch 18 to the first lamp 19 side.
If it is N, the base current of the first transistor 3 whose emitter is connected to the battery terminal 1 flows through the resistor 13 and the first lamp 19, so the first transistor 3 is turned on.

The second transistor 4 and the third transistor 5 each have their emitters commonly connected to the battery terminal 2, and their collectors have one end connected to the battery terminal 1 or the relay coil 6.
Since the base is connected to the collector of the first transistor 3 in common, when the first transistor 3 is turned on, the 21st transistor 4 and the third transistor 5 are turned on, and the relay is turned on at the same time. coil 6
is energized, the relay contact 15 is turned on, current flows through the lamp circuit, and the first lamp 19 lights up.

Here, a capacitor 7 whose one end is connected to the collector of the first transistor 3 is connected to the base of the second transistor 4.
Since a delay circuit consisting of a resistor 8 is connected to one end of the battery terminal 2, the charging current flowing through the capacitor 7 becomes O after a certain period of time, and the second transistor 4 is turned off. When the first transistor 3 is turned off, the current flowing through the relay coil 6 is reduced by the amount of the current flowing through the second transistor 4, as shown in the waveform diagram shown in FIG. However, since this old voltage is higher than the recovery voltage, the pull 9 relay maintains its operating state, the relay contact 15 is also in an ON state, and one lamp is lit.

The base of the first transistor 3 is connected to a 10° resistor capacitor 9. Resistance 12.11. Third transistor5. and a flashing circuit consisting of a resistor 13 are connected to the second transistor 4. When the capacitor 9 is charged by turning on the third transistor 5, the base potential of the first transistor 3 becomes @high potential after a certain period of time, and the first transistor 3 is turned off. When the first transistor 3 turns OFF, the third transistor 5 turns OFF, and the low current flowing through the relay coil 6 also stops flowing, and the relay contact 15 turns OFF.
The L lamp 19 is a treetop lamp.

The charge on capacitor 7 is discharged through resistors 16, 17, 8 to restore its function as a delay circuit, and the charge on capacitor 9 is discharged through resistors 13. It is discharged through the lamp 19, and the base potential of the first transistor 3 becomes LOW potential again after a certain period of time, and the above operation is repeated.

When the hazard signal switch 21 is turned on, the lamp 19 and the lamp 20 are connected to the load terminal 14, and the base current of the first transistor 3 is transferred to the resistor 13 and the lamp 19. Since the current flows through the lamp 20, the first transistor 3 is ONI, and thereafter performs the same operation as described above.

Note that the first transistor 3. 2nd transistor 4, 3rd transistor
Transistor 5. When the delay circuit and the like are integrated into an integrated circuit, the same operation as described above can be performed with a simple component configuration, the circuit becomes smaller, and reliability becomes higher.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a relay drive circuit according to an embodiment of the present invention, Fig. 2 is an electric circuit diagram when the invention is applied to a vehicle flashing device, and Fig. 3 is a voltage waveform diagram of a relay coil. be. 1.2... Battery one terminal, 3... First transistor, 4... Second transistor, 5... 31st ~ transistor, 6... Relay coil, 7... Capacitor,
8...1 person against. Patent applicant Tateishi Electric Co., Ltd.

Claims (2)

[Claims] (1) The first one has one electrode connected to one terminal of one battery, and the second one has one electrode connected to the other electrode of the transistor. The bases of the third transistors are connected in common, and the bases of the second . The other electrode of the third transistor is commonly connected to the other end of a coil of a relay whose one end is connected to one of the battery terminals, and when the first transistor is turned on, the second... Both third transistors are O
N, and energize the coil of the above relay,
After this relay operates, after a certain period of time, the second Third
A relay drive circuit comprising a delay circuit that turns off one of the transistors to reduce the current flowing through the coil of the relay. (2) First transistor, second transistor, third transistor
2. The relay drive circuit according to claim 1, wherein the transistor and the delay circuit are integrated into an integrated circuit.