JPS58142723A - Drive circuit for relay - 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] The present invention relates to a relay and a drive circuit that drive and control a relay by controlling conduction of a transistor connected in series with the relay, and is unlikely to malfunction even in the event of a power outage between the blades of an AC power supply. The present invention attempts to provide a relay drive circuit.

Generally, momentary power outages of AC power often occur on product assembly and manufacturing lines. The duration of this instantaneous AC power outage is normally 0.1 seconds.31 For example, when a relay is controlled by a timer circuit, there is a problem in that this 0.1 second power outage resets the timer circuit. .

Therefore, in a normal relay drive circuit, water is sprayed to prevent malfunction even in the event of a momentary power outage of 0.2 seconds. In order to lengthen this moment, the capacitance of the smoothing capacitor could be increased, but this resulted in a fairly large capacitor, which had the disadvantage of being unsuitable for commercialization in terms of space and cost.

Since the current flowing through the relay coil is relatively large, in the event of a momentary power outage, the relay is forcibly cut off using a transistor and the relay coil is turned off before the control circuit stops operating due to a drop in power supply voltage. The current flowing through the control circuit is passed through to the control circuit in order to extend the momentary power outage resistance of the control circuit.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 is an AC power supply, which includes a resistor of 2 degrees, a diode, 3. A series circuit of capacitors 4 is connected. Note that the resistor 2 and diode 3 constitute a rectifier circuit 6 that rectifies the AC power supply voltage.

A constant voltage power supply circuit 8 having a resistor 6 and a constant voltage diode connected in series is connected in parallel to the capacitor 4, and a capacitor 9 and a control circuit 1o are connected in parallel to the constant voltage diode. Relay coil 1 is connected to capacitor 4.
2, control transistor 13, and shield 1@transistor 1
Four series circuits are connected in parallel, and the control transistor is connected to the output of the control circuit 10 via a resistor 11, and the relay is controlled by the control transistor 130 energization control.

On the other hand, as a cutoff circuit for cutting off the relay coil, a resistor 19, a diode 20, and a capacitor 17 are connected in parallel to the series circuit of the rectifier circuit and capacitor 4 to the AC power supply 1. The circuit 21 is composed of a voltage regulator diode 18 and a resistor 16, which are smoothed by a capacitor 17.
The regulated voltage is connected to the cut-off phase l.
It is supplied through a resistor 15 connected in series to the base of the transformer 14.

Next, the operation in the above configuration will be explained.

The AC power supply voltage is rectified by the rectifier circuit 6, smoothed by the capacitor 4, and made into a constant voltage by the constant voltage power supply circuit 8.
) is generated and supplied to the control circuit 10. Control circuit 10
The output is reduced in pressure by the resistor 11 and becomes an input signal to the L-transistor 13. This signal controls the conduction of the transistor 13, causing current to flow through the relay coil 9, thereby controlling the relay.

In addition, as a cutoff signal, the AC power supply 1 is rectified by a rectifier circuit 21, smoothed by a capacitor 17, and then connected by a constant voltage diode 1.
The voltage is made into a constant voltage by 8, and is supplied to the cutoff transistor 14 through a resistor 15. Resistor 16 is for discharging capacitor 17.

- In the state described above, if the electric gap L is turned off from time T1 to T4-1, the potential across the capacitor 4 (a in Figure 2) is discharged by the human slope.At the same time, the control circuit The input power supply voltage of 10 (b in Figure 2) also has a slope of D, and the voltage across the capacitor 17 (C in Figure 2) also has a slope of 1 of F.
Discharge begins at an angle.

At this time, the resistance value of the equivalent resistance 22 protruding from the capacitor 4 is R22, and the capacitance of the capacitor 4 is 04. Assuming that the resistance value of the resistor 16 is R16 and the capacitance of the capacitor 17 is 017, each is set so that the following equation holds true.

(4R22)C-+7Ra, from the discharge time constant of capacitor 4, capacitor 1
If the discharge time constant of capacitor 7 is made small, the voltage across capacitor 17 will be higher than the voltage across capacitor 4.
decrease. Then, at time T2, the capacitor 17
When the voltage across the relay coil 12 decreases to vl, the cutoff transistor 14 turns off and cuts off the current flowing through the relay coil 12.

After time T2, since the voltage kJ across the capacitor 40 is only passed to the control circuit, it is discharged at a slope B that is gentler than the slope, and the input voltage of the control circuit 10 is still discharged at a slope F that is gentler than the slope. . That is, the control circuit 10
If the input voltage that decreases by seven degrees is v2, the time required for the input terminal of the control circuit 10 to reach V2 after a power outage occurs is the instantaneous power outage resistance time, so if the control circuit 10 If the relay was not previously at 0FFL, the control circuit input voltage would be reset at one time T3 in FIG. 2, but would extend to time T4 in this embodiment.

As is clear from the following explanation, the present invention is very effective as a countermeasure against instantaneous power outages that occur on production lines, and if the capacity of the capacitor is appropriately selected,
This creates a circuit that is highly resistant to instantaneous power outages.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of a relay drive circuit showing one embodiment of the present invention, and FIG. 2 1a, b, c, and d are signal waveform diagrams of essential parts of the same electrical circuit. 1...AC power supply, 2...Resistance, 3...
...Diode, 4...Capacitor, 8...
... Constant voltage power supply circuit, 12 ... Relay coil,
13...Relay control transistor, 14...
... Cutoff transistor, 10 control circuit, 16...
...Resistor, 17...Capacitor. Name of agent: FPJ Satoshi Toshio Nakao and one other person Figure 1

Claims (1)

[Claims] A series circuit of a resistor, diode, and capacitor connected to an AC power supply, a constant voltage power supply circuit connected in parallel to the capacitor, a relay coil, a relay control transistor, and a cutoff transistor connected in parallel to the capacitor. a series circuit, a control circuit that is driven by the output of the constant voltage power supply circuit and controls conduction of the transistor for controlling the relay; and a control circuit that is driven by the output of the constant voltage power supply circuit and controls conduction of the transistor for controlling the relay; A relay 1 drive circuit comprising a cutoff circuit that cuts off the connection/disconnection transistor before entering the reset state.