JPH01200531A - Malfunction prevention device for signal transmission circuits including double winding latching relays - Google Patents

Abstract

PURPOSE:To prevent the malfunction of a signal transmission circuit including a latch relay by connecting the coil of the compound wound latch relay to the first diode in parallel and connecting the series circuit of a reverse polarity second diode and the latch relay coil lo a capacitor in parallel. CONSTITUTION:When a set pulse Va is given to a set coil 2a, induced electromotive voltage generated respectively at leading and trailing ports of the pulse in a reset coil 2b is shunted by the first diode Db. The second diode D2 is also involved in the aforesaid process. Also, the other side of the induced electromotive voltage (this has reverse polarity and the upper side of the reset coil 2b is positive and the lower side thereof is negative) has reverse polarity against the second diode D2' and therefore this diode D2, comes to have high impedance. As a result, shunt effect due to a capacitor C2 connected in parallel to the series circuit of the second diode D2 and the reset coil 2b works very effectively and the induced electromotive voltage is well suppressed. According to the aforesaid construction, a signal free from induced electromotive voltage is inputted to a post-stage circuit 3 as shown in Vb and the circuit 3 is free from malfunction.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is useful when a rear stage circuit is connected to a front stage circuit together with a multi-winding latch relay to transmit a logic signal from the front stage circuit to the rear stage circuit. The present invention relates to a malfunction prevention device for a signal transmission circuit including a certain multi-winding latch relay.

BACKGROUND OF THE INVENTION A circuit device on which the present invention is based is shown in FIG. This circuit has a configuration in which a multi-winding latch relay 2 is connected to a front-stage circuit 1 and a second-stage circuit 3 is connected, and diodes D&+Db are connected in parallel to a set coil 2a and a reset coil 2b of the multi-winding latch relay 2, respectively. It is something that is true. These diodes D and Db are commonly used to prevent back electromotive force generated in the relay coil, and prevent back electromotive force generated in those coils when the drive current of set coil 2 & reset coil 2b is stopped. This shunts the back electromotive force from being applied to the transistors JQa and Qb in the front stage circuit 1 via the DC power supply TRY, thereby preventing overvoltage damage to the transistors QΔ and Qb. For example, when the transistor Qa is turned on by a cent pulse to cause a drive current to flow through the cent coil 2a, the voltage va at the connection point between the transistor Qa and the set coil 2& is as shown by the solid line in FIG. 8, and is shown by the dotted line. The back electromotive voltage generated is shunted by the diode D and does not exist. Therefore, the transistor Qa is protected from being applied with a back electromotive voltage.

Problems to be Solved by the Invention However, when using the multi-winding latch relay 2, there is another problem to be solved. That is, the double-winding latch relay 2 has a set coil 21L and a reset coil 2b magnetically coupled, and has the effect of operating relay contacts (not shown) like a flip-flop by alternately passing a pulse current through each coil. This relay contact selectively controls a load (not shown). In this case, when the set coil 2& is driven with the set pulse shown by v2L as shown by the solid line in FIG. 8, the reset coil 2b
Induced electromotive voltages of opposite polarity are generated at the falling and rising portions of the set pulse. One of these induced electromotive voltages is shunted by the diode Db, but the other appears via the DC power supply vnr as shown by the solid line in FIG. 8 vb (voltage at the connection point between the transistor Qb and the reset coil 2b) This will cause the logic of the subsequent circuit 2 to malfunction. In this case, there will be no problem if the input to the rear circuit 2 is taken from the base side of the transistors Qa and Qb in the front circuit 1 via an inverter, but since the front circuit 1 is an integrated circuit, such signal extraction is not possible. Cases where there are no terminals are highlighted as issues that must be solved.

The present invention was invented based on this background, and has an object to appropriately prevent malfunctions of a signal transmission circuit including a multi-winding latch relay.

Means for Solving the Problems The present invention is provided with a structure in which a post-stage circuit is connected to a pre-stage circuit together with a multi-winding latch relay, and a first diode is connected in parallel to a cent coil and a reset coil of the multi-winding latch relay, respectively. A second diode having a direction opposite to the first diode is connected in series to at least one of the coils that is connected to the subsequent circuit, and a capacitor is connected to the series circuit of this coil and the second diode. The present invention constitutes a malfunction prevention device for a signal transmission circuit including a multi-winding latch relay, which is characterized in that the following are connected in parallel.

According to the present invention, it is possible to appropriately shunt the induced electromotive force generated in the coil of the multi-winding latch relay from the other coil, thereby preventing malfunction of the subsequent stage circuit. That is, one side of the induced electromotive force is shunted by the first diode, and the other side is shunted by the second diode, which includes a high impedance component of the second diode, which has the opposite polarity to this induced electromotive force, and the coil of the multi-winding latch relay. It is suppressed by shunting the series circuit with a capacitor. Since the capacitor shunts high impedance components, a low capacitance capacitor is sufficient, contributing to cost reduction and space saving, and the response of the relay contact does not become dull.

Embodiment Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

Embodiment 1 (See FIGS. 1 and 2) The circuit according to this embodiment 1 differs from the prerequisite circuit of the present invention shown in FIG. 7 in the following points. That is, the set coil 2a and reset coil 2b of the double winding latch relay 2 include a diode (%+Dl) (hereinafter referred to as a first diode in order to distinguish it from another diode described later in the present invention).
The second diode D1. D2 are connected in series, and the set coil 2a and the second diode D
.

Capacitors C4 and C2 are connected in parallel to the series circuit between the reset coil 2b and the second diode D2, respectively. Note that the first diode Da,
Db is connected in parallel to the set coil 22L and reset coil 2b via second diodes D and ID2, respectively.

In such a configuration, when a set pulse is applied to the set coil 2a as shown in Fig. 2 Va, the induced electromotive force generated in the reset coil 2b at the falling and rising parts of this set pulse is as follows. Suppressed by circuit operation. That is, one of the induced electromotive voltages is caused by the first diode Db as in the case of the prerequisite circuit of the present invention shown in FIG.
shunted by. Note that the shunt effect in this embodiment is also performed via the second diode D2.

Also, the other side of the induced electromotive force (opposite polarity to the above one,
In FIG. 1, the upper side of the reset coil 2b is opposite to the second diode D2-, so the second diode D2 has a high impedance, and the reset coil 2b and the second diode D2 have opposite polarity. The shunt effect of capacitor C2 connected in parallel to the series circuit (high impedance) with coil 2b is extremely effective, and even if capacitor C2 has a fairly low capacity, the impedance of capacitor C2 is relatively small. from,
sufficiently suppressed. By the way, the second diode D2
If the first diode Db and capacitor C2 are simply connected in parallel to the reset coil 2b by shorting both ends of the capacitor C2, a capacitance of several μF is required for the capacitor C2, and the response of the relay contact (not shown) is In the present invention, the capacitor C2 is 0.01μ, although it becomes considerably dull.
The induced electromotive voltage can be sufficiently suppressed at around F, and the response of the relay contact will not be affected by the side stage. In this way, as shown in FIG. 2vb, a signal with no induced electromotive force is input to the subsequent stage circuit 3, so that the subsequent stage circuit 3 does not malfunction. Of course, even when the reset pulse is supplied to the reset coil 2b, the center coil 2'
The first diode Da on the a side, the second diode D1 . Capacitor C1 acts to prevent malfunction from occurring in the subsequent stage circuit 3.

Embodiment 2 (See FIGS. 3 to 6) In this embodiment, the set coil 2+L and reset coil 2b of the multi-winding latte relay 2 are connected to the subsequent circuit 3, that is, the reset coil 2b. for,
As in the first embodiment, the first diode Db, the second diode D2 and the capacitor C2 are connected, and the second diode D1. Capacitor C1 is not connected, and first diode D& is connected.

In such a configuration, as shown in FIG.
Similarly, the induced electromotive force is suppressed, so the subsequent circuit 3
Do not allow it to malfunction. Also, as shown in FIG. 6vb, when a reset pulse is given to the reset coil 2b, an induced electromotive force appears in the Va constant voltage, but since the set coil 2a side is not connected to the subsequent circuit 3, this induced electromotive force There is no problem in the operation of the subsequent stage circuit 3.

As is clear from this embodiment, a first diode should be connected in parallel to each coil of the double-winding latch relay 2, but at least one of the coils connected to the subsequent circuit 3 should be connected in parallel to each coil. The object of the present invention can be achieved by connecting a second diode in series with the coil in a direction opposite to that of the first diode, and connecting a capacitor in parallel to the series circuit of this coil and the second diode.

Embodiment 3 (See Fig. 6) In this embodiment, the first diode Db is connected in parallel to the reset coil 2b without intervening the second diode D2, and the induced electromotive voltage can be suppressed as described in both embodiments. There is no difference in the action. Of course, the connections of the first diodes DiL, Di) of the first embodiment and the first diode Db of the second embodiment can be changed as in the present embodiment.

Effects of the Invention According to the present invention, when a rear-stage circuit is connected to a front-stage circuit together with a multi-winding latch relay to transmit a logic signal from the front-stage circuit to a rear-stage circuit, the induced electromotive force generated in the coil of the relay can be appropriately controlled. Because it can be suppressed accurately, it is extremely useful in preventing malfunctions in subsequent circuits, and since the additional capacitors only need to be of low capacity, it contributes to cost and space savings, and the response of relay contacts is also independent. It does not interfere with the installation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of Embodiment 1 according to the present invention, FIG. 2 is a time chart showing the operation of the same circuit, FIG. 3 is a circuit diagram of Embodiment 2 according to the present invention, and FIGS. 4 and 5 are FIG. 6 is a time chart showing the operation of the same circuit, FIG. 6 is a circuit diagram of Embodiment 3 according to the present invention, FIG. 7 is a circuit diagram that is a premise of the present invention, and FIG. 8 is a time chart showing the operation of the same circuit. . 1... Pre-stage circuit, 2... Multi-winding latch relay, 2a... Set coil, 2b...
...Reset coil, 3...Late stage circuit, Da
・Db...First diode, D,, D2...
...Second diode, C1, C2... Capacitor.゛Name of agent Patent attorney Toshio Nakao and 1 other person2-
a Winding pipe valve relay 20 - Set coil C1, Cp - Kotsunap Fig. 2 bL Fig. 3 Fig. 4 bH Fig. 5 Fig. 6

Claims (1)

[Claims] A configuration is provided in which a rear stage circuit is connected to the front stage circuit together with a multi-winding latch relay, and a first diode is connected in parallel to each of a set coil and a reset coil of the double winding latch relay, and at least one of the coils is connected to the rear stage circuit. A second diode having a direction opposite to that of the first diode is connected in series to the coil connected to the second diode, and a capacitor is connected in parallel to the series circuit of this coil and the second diode. Malfunction prevention device for signal transmission circuits including line latch relays.