JPH04174928A - Relay circuit - Google Patents

Abstract

PURPOSE:To make the subject circuit small in size by reducing the capacitor rating and the loss generated in a capacitor and a constant current circuit by providing a relay coil and a constant current circuit connected in series to a DC power source, and a capacitor for adjusting the circuit constant of the coil. CONSTITUTION:A time constant capacitor 25 is connected in parallel to a relay coil 19 instead of a conventional time constant capacitor. The rating voltage of the capacitor can be reduced thereby in comparison with the conventional one which is connected directly to a rectifying capacitor 10 which is a power source, and thus the size of the capacitor is made compact. Through operation, that is energization, of a constant current circuit 21 the voltage of the capacitor 10 is decreased appropriately to reduce the sharing voltage at the circuit 21, thereby reducing the collector loss. It is thus possible to eliminate the installation of an apparatus such as a cooling fan.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a relay circuit used, for example, in a demagnetizing device for a picture tube in a television receiver.

[Conventional technology]

FIG. 2 is a circuit diagram showing a picture tube degaussing device to which this kind of conventional relay circuit is applied. Note that the picture tube is demagnetized by, for example, passing an alternating current through a degaussing coil when the power is turned on and gradually attenuating this current to prevent color unevenness due to the influence of earth's magnetism. Further, the relay circuit is adopted here so that it can be used commonly for power supply voltages of 100V and 200V.

In the figure, (1) is the power supply, which may be 100V or 200V depending on the specifications of the receiver body. (2) is the power switch, (3) is the degaussing coil, 4) and (5)
POSISTOR 1 (6) is a degaussing switch for 100V circuit and 200V circuit, respectively, and POSISTOR (7) is a relay, and its fixed contact (8a) and fixed contact (8b) are POSISTOR (4) and POSISTOR ( 5), and the movable contact (8c) is connected to the ground part. Now that the main circuit of the degaussing device has been described above, the power supply voltage discrimination circuit and the excitation circuit for relay m will be explained.

(9) is a rectifier diode, (lO) is a rectifier capacitor,
(11) is a voltage detection circuit connected to the rectifier capacitor (10) via a resistor (+2) (13),
) When a voltage corresponding to 100V is detected, the changeover switch (14) is turned on, and when the voltage corresponds to 200V, the changeover switch (14) is turned off.

(15) is a voltage blocking diode, (16) is a time constant capacitor for adjusting the circuit time constant of relay (7), (+7) (18) is a resistor, (19) is a relay coil, (20) is a snubber (21) A constant current circuit connected in series with a coil (one), consisting of transistors (22) (23) and a resistor (24).

Next, the operation will be explained. First, a 100ν power supply (1
) is applied. Power switch (
2), the rectifying capacitor (10) is charged and the terminal voltage becomes approximately 37 times the voltage of the current R(1), that is, 100V. The voltage detection circuit (11) is connected to this rectifier capacitor (
10), turn on the selector switch (14).

As a result, the constant current circuit (21) is short-circuited and the relay coil (19) is not excited, so the movable contact (8C) remains held on the fixed contact (8a) side, and the degaussing switch ( 6) is turned on, the degaussing coil (3
) and the POSISTOR (4) will be inserted into the circuit of the power supply (1). Then, a current flows through the demagnetizing coil (3), thereby starting the demagnetizing operation of the picture tube. The temperature of the POSISTOR 4) rises due to its energization, its resistance value increases accordingly, and the current in the demagnetizing coil (3) gradually decreases to achieve a predetermined level of demagnetization.

Next, when this device is applied to the 200v power supply (1), the voltage detection circuit (11) operates when the power switch (2) is turned on, and the changeover switch (14) is turned off. .

As a result, the constant current circuit (21) operates, current is supplied to the relay coil (19), and the movable contact (8c) is driven to come into contact with the fixed contact (8b). Here, use the degaussing switch.
When Sochi (6) is turned on, the degaussing coil (3), POSISTOR (5), and 200V power supply (1) will be inserted into the circuit, and the prescribed demagnetizing effect will be performed as in the case of the 100V circuit. be exposed.

Here, the time constant capacitor (16) is the relay coil (1
The time constant of the current flowing through 9) is adjusted and coordinated with the operation timing of the degaussing switch (6) to prevent the +00ν circuit POSISTOR 4) from being accidentally inserted into the 200V power supply circuit. .

[Problem to be solved by the invention]

Conventional relay circuits are configured as described above, so
In particular, since a value obtained by rectifying the voltage of the power supply (1) is directly applied to the time constant capacitor (16), the capacitor becomes a large capacitor with a correspondingly high withstand voltage. In addition, the same capacitor has a considerably large capacitance value in order to obtain a predetermined time constant, and from this point of view as well, it becomes large in size.As a result of the large capacitance, the current of the constant current circuit (21) (The voltage of the time constant capacitor (16) does not decrease much, and as a result, the voltage of the transistor (221 (2) constituting the constant current circuit (21)
The voltage borne between the collector and emitter of 31 becomes large, and the collector loss increases. Therefore, it may be necessary to increase the cooling capacity by providing a cooling fan or the like.

This invention was made to solve the above-mentioned problems, and aims to reduce the rating of the capacitor and reduce the loss generated in the constant current circuit, thereby making the device smaller and less expensive. be.

[Means to solve the problem]

A relay circuit according to the present invention includes a relay coil and a constant current circuit that are connected in series with each other to a DC power source, and a capacitor that is connected in parallel with the relay coil and adjusts a circuit time constant of the relay coil. It's ours.

``Function〕 The tensa operates with the voltage of the relay coil, so
The applied voltage will be lower than the voltage of the DC power supply. Furthermore, by appropriately setting the regulation of the DC power supply, it is possible to reduce the voltage borne by the constant current circuit.

〔Example〕

FIG. 1 is a circuit diagram showing a degaussing device to which a relay circuit according to an embodiment of the present invention is applied.
What is different from the circuit shown in the figure is the conventional time constant capacitor (16
) instead of the time constant capacitor (25) and the relay coil (
1) in parallel.

The basic operation when the voltage of the power supply (1) is 100v or 200v is the same as before, so the explanation will be omitted to avoid duplication, but in this case, the time constant of the current of the relay coil (19) is the time constant. It will be adjusted by a capacitor (25).

Therefore, compared to the case of a conventional time constant capacitor (16) directly connected to a rectifying capacitor (10) which is a DC power source, the rated voltage of the capacitor can be reduced, and the capacitor can be made smaller accordingly.

In addition, the voltage of the rectifying capacitor (10) decreases appropriately due to the operation of the constant current circuit (21), that is, energization, and the voltage shared by the constant current circuit (21) decreases accordingly, reducing its collector loss. Therefore, equipment such as cooling fans can be reduced.

Although the above embodiments have been described with reference to the case of application to a picture tube degaussing device, the present invention can be similarly applied to various relay circuits in which a relay coil and a constant current circuit are connected in series to a DC power source. It has the same effect.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to reduce the rated voltage of the capacitor and downsize it, and it is also possible to reduce the loss generated in the constant voltage circuit.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a picture tube degaussing device to which a relay circuit according to an embodiment of the present invention is applied, and FIG. 2 is a similar circuit diagram of a conventional circuit. In the figure, (7) beam-1 (10) is (a rectifier capacitor as a σ current power source, (19) beam-coil, (2
1) is a constant current circuit, and (25) is a time constant capacitor as a capacitor. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent: Masuo Oiwa, patent attorney

Claims (1)

[Claims] A relay circuit comprising a relay coil and a constant current circuit that are connected in series to a DC power source, and a capacitor that is connected in parallel with the relay coil and adjusts a circuit time constant of the relay coil.