CN204558366U - A kind of control relay circuit with isolation - Google Patents

Abstract

The utility model discloses a relay control circuit with isolation, which relates to the technical field of relay control circuits. The circuit has no potential safety hazard when the relay control circuit is overhauled with power on. The base of the transistor Q1 is connected to the other end of the resistor R2, the base of the transistor Q2 is connected to the other end of the resistor R3; the base of the transistor Q4 is connected to the emitter of the transistor Q3, and the collector of the transistor Q3 is connected to the resistor On one end of R4, the base of the transistor Q3 is connected to one end of the resistor R5, the other end of the resistor R4 is connected to the 5V power terminal, and the other end of the resistor R5 is connected to the closing end of the relay; the base of the transistor Q6 is connected to On the emitter of the transistor Q5, the collector of the transistor Q5 is connected to one end of the resistor R6, the base of the transistor Q5 is connected to one end of the resistor R7, the other end of the resistor R6 is connected to the 5V power terminal, and the resistor R7 The other end is connected to the switching end of the relay.

Description

A relay control circuit with isolation

technical field

The utility model relates to the technical field of relay control circuits, in particular to a relay control circuit with isolation.

Background technique

At present, the relay control circuit directly connects the control terminal to the 12V power terminal of the relay. Since the 12V power terminal power supply not only supplies power to the drive terminal of the relay control circuit, but also supplies power to the control terminal of the relay control circuit, the stability of the power supply to the drive terminal is easily affected by the stability of the power supply to the control terminal. The power supply of the driving end is unstable, and it is easy to generate a peak voltage of about 35V on the triode, which is easy to burn out the triode, thus affecting the service life of the relay. In addition, the existing relay control circuit is directly connected to the strong current, resulting in potential safety hazards in the maintenance of the relay control circuit with strong current. Therefore, it is very necessary to design a relay control circuit with isolation that can prevent the transistor from being damaged by the peak voltage generated by the relay action, and that there is no potential safety hazard when the relay control circuit is overhauled.

Utility model content

The utility model is to solve the problem that the power supply of the drive terminal and the control terminal of the existing relay control circuit is the same power supply, the stability of the power supply of the drive terminal is easily affected by the stability of the power supply of the control terminal, and it is easy to generate a higher peak voltage on the triode Burn out the triode, thus affecting the service life of the relay, and there are safety hazards in overhauling with strong current. The stability of the power supply at the drive end will not be affected by the stability of the power supply at the control end. The power supply at the drive end is stable. It will not generate high peak voltage on the triode, and the triode is not easy to burn out, thereby prolonging the service life of the relay control circuit, and an isolated relay control circuit without safety hazards when the relay control circuit is repaired live.

The above technical problems are solved through the following technical solutions:

A relay control circuit with isolation, comprising: resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, diode D1, diode D2, transient voltage suppression diode TVS, transistor Q1, transistor Q2 , Transistor Q3, Transistor Q4, Transistor Q5, Transistor Q6, Capacitor C1, Node 1, Node 2, Node 3, Node 4, Node 5, Node 6, Node 7, Node 8, Node 9 Node, node ten, resistor R8, resistor R9, resistor R10, resistor R11, resistor R12, resistor R13, optocoupler OPT22, optocoupler OPT23, wire ground GND, relay closing terminal, relay switching terminal, 12V The power supply terminal, the 5V power supply terminal and the signal ground terminal SGND; the negative terminal of the diode D1, the 12V power supply terminal, one end of the resistor R1 and the negative terminal of the diode D2 are respectively connected to the No. 1 node; the transistor Q1 The emitter, the other end of the resistor R1 and the emitter of the transistor Q2 are respectively connected to the second node; the positive end of the diode D1, the collector of the transistor Q1, one end of the transient voltage suppression diode TVS, one end of the resistor R3, One end of the capacitor C1 and the collector of the transistor Q4 are respectively connected to the third node; the positive end of the diode D2, the collector of the transistor Q2, the other end of the transient voltage suppression diode TVS, one end of the resistor R2, and the capacitor C1 The other end and the collector of the triode Q6 are respectively connected to the No. 4 node; the emitter of the triode Q4, the signal ground terminal SGND, the emission of the triode Q6, one end of the resistor R10 and one end of the resistor R13 are respectively connected to the No. 5 node; The closing end of the relay, one end of the resistor R8, and one end of the resistor R9 are respectively connected to the No. 6 node; On the node; the switch-up end of the relay, one end of the resistor R11, and one end of the resistor R12 are respectively connected to the No. 8 node; the other end of the resistor R9, the No. 2 port of the optocoupler OPT22, the other end of the resistor R12, The No. 2 port of the optocoupler OPT23 and the wire grounding terminal GND are respectively connected to the No. 9 node; the other end of the resistor R7, the other end of the resistor R13 and the No. 3 port of the optocoupler OPT23 are respectively connected to the No. 10 node The base of the transistor Q1 is connected to the other end of the resistor R2, the base of the transistor Q2 is connected to the other end of the resistor R3; the base of the transistor Q4 is connected to the emitter of the transistor Q3, and the collector of the transistor Q3 is connected to On one end of the resistor R4, the base of the transistor Q3 is connected to one end of the resistor R5, and the other end of the resistor R4 is connected to the 5V power terminal; the base of the transistor Q6 is connected to the emitter of the transistor Q5, and the collector of the transistor Q5 The electrode is connected to one end of the resistor R6, the base of the transistor Q5 is connected to one end of the resistor R7, and the resistor R The other end of 6 is connected to the 5V power terminal; the other end of resistor R8 is connected to port 1 of optocoupler OPT22; the other end of resistor R11 is connected to port 1 of optocoupler OPT23; optocoupler OPT22 The No. 4 port of the optocoupler OPT23 is connected to the 5V power terminal, and the No. 4 port of the optocoupler OPT23 is also connected to the 5V power terminal.

R1 is a current limiting protection resistor to prevent damage to devices behind the relay control circuit caused by high current.

D1, D2, TVS, and C1 are protection devices to prevent the high peak voltage of about 35V generated by the action of the relay control circuit from causing damage to the triode.

R2 and R3 are the base current control resistors of the triode, so that the triode is in a relatively stable state when it is working.

R4, R6, Q3, Q5 provide driving current for the relay control circuit;

R8 and R11 respectively provide the set working current for the optocoupler OPT22 and the optocoupler OPT23.

Working process: When the closing terminal of the relay changes from low level to high level, the high level is limited by the resistor R8, and then the light-emitting diode of the optocoupler OPT22 is turned on, so that the light-emitting diode of the optocoupler OPT22 generates Optical signal, so that the photosensitive transistor of the optocoupler OPT22 is turned on, and then the seventh node is changed from low level to high level. At this time, the triode Q3 is turned on, and then the triode Q4 is turned on. The high level becomes low level, and the triode Q2 controlled by the resistor R3 is turned on. At this time, there is a sufficient pressure difference between the two control terminals of the relay control circuit to make the relay control circuit move towards the closing terminal of the relay. Similarly, when the switching terminal of the relay changes from low level to high level, the high level is limited by the resistor R11, and then the light-emitting diode of the optocoupler OPT23 is turned on, so that the light-emitting diode of the optocoupler OPT23 generates Optical signal, so that the photosensitive transistor of the optocoupler OPT23 is turned on, and then the tenth node is changed from low level to high level. The high level becomes low level, and the triode Q1 controlled by the resistor R2 is turned on. At this time, there is a sufficient pressure difference between the two control terminals of the relay control circuit to make the relay control circuit move towards the relay switching terminal.

In this scheme, the two control terminals of the relay control circuit are the No. 3 node and the No. 4 node. R4, R6, Q3, and Q5 provide driving current for the relay control circuit through the 5V power supply, which is more stable and reliable than the previous pull-up to the 12V power supply (the power supply is not stable due to the fluctuation of the mains power). The stability of the power supply at the driving end of the relay control circuit will not be affected by the stability of the power supply at the control end. The power supply at the driving end is stable and will not generate high peak voltage on the triode. The triode is not easy to burn out, thereby prolonging the service life of the relay. , and there is no potential safety hazard when the relay control circuit is overhauled live. The scheme is low in cost and high in reliability. This solution uses the optocoupler OPT22 and optocoupler OPT23 to realize the function of converting the electrical signal to the optical signal and then to the electrical signal, and achieves electrical isolation, so that the relay control circuit part is separated from the strong electric terminal and becomes safer

Preferably, both the transistor Q1 and the transistor Q2 are PNP type transistors. This type of triode connection circuit is simple and easy to control, with good stability.

Preferably, the triode Q3, the triode Q4, the triode Q5 and the triode Q6 are all NPN type transistors. This type of triode connection circuit is simple and easy to control, with good stability.

The utility model can achieve the following effects:

The stability of the power supply at the driving end of the relay control circuit of the utility model will not be affected by the stability of the power supply at the control end, the power supply at the driving end is stable, and no high peak voltage will be generated on the triode, and the triode is not easy to burn out, thereby prolonging the relay life. service life, and there is no potential safety hazard when the relay control circuit is overhauled live. The utility model has low cost and high reliability.

Description of drawings

Fig. 1 is a schematic diagram of a circuit principle connection structure of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

An embodiment, a relay control circuit with isolation, as shown in Figure 1, includes: resistor R1, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R7, diode D1, diode D2, transient voltage Suppression diode TVS, PNP transistor Q1, PNP transistor Q2, NPN transistor Q3, NPN transistor Q4, NPN transistor Q5, NPN transistor Q6, capacitor C1, No. 1 node (101), No. 2 node (102), No. 3 node (103 ), No. 4 node (104), No. 5 node (105), No. 6 node (106), No. 7 node (107), No. 8 node (108), No. 9 node (109), No. 10 node (110) , Resistor R8, Resistor R9, Resistor R10, Resistor R11, Resistor R12, Resistor R13, Optocoupler OPT22, Optocoupler OPT23, Wire Ground Terminal 6ND, Relay Closing Terminal, Relay Switching Terminal, 12V Power Terminal, 5V Power terminal and signal ground terminal SGND. The negative end of the diode D1, the 12V power supply terminal, one end of the resistor R1 and the negative end of the diode D2 are respectively connected to the No. 1 node. The emitter of the PNP transistor Q1, the other end of the resistor R1 and the emitter of the PNP transistor Q2 are respectively connected to the second node. The positive end of the diode D1, the collector of the PNP transistor Q1, one end of the transient voltage suppression diode TVS, one end of the resistor R3, one end of the capacitor C1 and the collector of the NPN transistor Q4 are respectively connected to the third node. The positive end of the diode D2, the collector of the PNP transistor Q2, the other end of the transient voltage suppression diode TVS, one end of the resistor R2, the other end of the capacitor C1 and the collector of the NPN transistor Q6 are respectively connected to the fourth node. The emitter of the NPN transistor Q4, the signal ground terminal SGND, the emitter of the NPN transistor Q6, one end of the resistor R10 and one end of the resistor R13 are respectively connected to the fifth node. The closing terminal of the relay, one terminal of the resistor R8 and one terminal of the resistor R9 are respectively connected to the No. 6 node. The other end of the resistor R5, the other end of the resistor R10 and the port 3 of the optocoupler OPT22 are respectively connected to the node 7. The switching end of the relay, one end of the resistor R11 and one end of the resistor R12 are respectively connected to the No. 8 node. The other end of the resistor R9, the No. 2 port of the optocoupler OPT22, the other end of the resistor R12, the No. 2 port of the optocoupler OPT23 and the wire ground GND are respectively connected to the No. 9 node. The other end of the resistor R7, the other end of the resistor R13 and the port 3 of the optocoupler OPT23 are respectively connected to the tenth node. The base of the PNP transistor Q1 is connected to the other end of the resistor R2, and the base of the PNP transistor Q2 is connected to the other end of the resistor R3. The base of NPN transistor Q4 is connected to the emitter of NPN transistor Q3, the collector of NPN transistor Q3 is connected to one end of resistor R4, the base of NPN transistor Q3 is connected to one end of resistor R5, and the other end of resistor R4 is connected to On the 5V power terminal. The base of NPN transistor Q6 is connected to the emitter of NPN transistor Q5, the collector of NPN transistor Q5 is connected to one end of resistor R6, the base of NPN transistor Q5 is connected to one end of resistor R7, and the other end of resistor R6 is connected to On the 5V power terminal. The other end of the resistor R8 is connected to the No. 1 port of the optocoupler OPT22; the other end of the resistor R11 is connected to the No. 1 port of the optocoupler OPT23; the No. 4 port of the optocoupler OPT22 is connected to the 5V power terminal. Port No. 4 of the optocoupler OPT23 is also connected to the 5V power terminal.

R1 is a current limiting protection resistor to prevent damage to devices behind the relay control circuit caused by high current.

D1, D2, TVS, and C1 are protection devices to prevent the high peak voltage of about 35V generated by the action of the relay control circuit from causing damage to the triode.

R2 and R3 are the base current control resistors of the triode, so that the triode is in a relatively stable state when it is working.

R4, R6, Q3, Q5 provide driving current for the relay control circuit.

R8 and R11 respectively provide the set working current for the optocoupler OPT22 and the optocoupler OPT23.

work process:

When the closing terminal of the relay changes from low level to high level, the high level passes through the current limit of the resistor R8, and then conducts through the light-emitting diode of the optocoupler OPT22, so that the light-emitting diode of the optocoupler OPT22 generates an optical signal. Thereby make the photosensitive transistor of optocoupler OPT22 conduction, and then make No. 7 node change from low level to high level, at this moment, NPN triode Q3 conduction, and then NPN triode Q4 conduction, No. 3 node (103) by The original high level becomes low level, and the PNP transistor Q2 controlled by the resistor R3 is turned on. At this time, there is enough pressure difference between the two control terminals of the relay control circuit to make the relay control circuit move towards the closing terminal of the relay.

Similarly, when the switching terminal of the relay changes from low level to high level, the high level is limited by the resistor R11, and then the light-emitting diode of the optocoupler OPT23 is turned on, so that the light-emitting diode of the optocoupler OPT23 generates Optical signal, so that the photosensitive transistor of the optocoupler OPT23 is turned on, and then the tenth node is changed from a low level to a high level. At this time, the NPN transistor Q5 is turned on, and then the NPN transistor Q6 is turned on. The fourth node ( 104) Change from the original high level to low level, and the PNP transistor Q1 controlled by the resistor R2 is turned on. At this time, there is a sufficient pressure difference between the two control terminals of the relay control circuit to make the relay control circuit move toward the relay switching terminal.

In this example, the two control terminals of the relay control circuit are the third node (103) and the fourth node (104). R4, R6, Q3, and Q5 provide driving current for the relay control circuit through the 5V power supply, which is more stable and reliable than the previous pull-up to the 12V power supply (the power supply is not stable due to the fluctuation of the mains power). The stability of the power supply at the driving end of the relay control circuit in this example will not be affected by the stability of the power supply at the control end. The power supply at the driving end is stable and will not generate high peak voltage on the triode, and the triode is not easy to burn out, thereby prolonging the relay. service life, and there is no potential safety hazard when the relay control circuit is overhauled live. This example has low cost and high reliability.

In this example, the function of converting electrical signal to optical signal and then to electrical signal is realized through optocoupler OPT22 and optocoupler OPT23, and electrical isolation is achieved, so that the relay control circuit part is separated from the strong electric terminal and becomes safer.

The embodiments of the utility model are described above with reference to the accompanying drawings, but the implementation is not limited by the above embodiments, and those skilled in the art can make various changes or modifications within the scope of the appended claims.

Claims (3)

1. the control relay circuit with isolation, it is characterized in that, comprise: resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, diode D1, diode D2, transient voltage suppressor TVS, triode Q1, triode Q2, triode Q3, triode Q4, triode Q5, triode Q6, electric capacity C1, a node (101), No. two nodes (102), No. three nodes (103), No. four nodes (104), No. five nodes (105), No. six nodes (106), No. seven nodes (107), No. eight nodes (108), No. nine nodes (109), No. ten nodes (110), resistance R8, resistance R9, resistance R10, resistance R11, resistance R12, resistance R13, photoelectrical coupler OPT22, photoelectrical coupler OPT23, electric wire earth terminal GND, relay closes a floodgate and holds, relay is operated a switch end, 12V supply terminals, 5V supply terminals and signal ground end SGND, the negative pole end of described diode D1,12V supply terminals, one end of resistance R1 and the negative pole end of diode D2 are connected on a node, the emitter of the emitter of described triode Q1, the other end of resistance R1 and triode Q2 is connected on No. two nodes, the collector electrode of one end of the positive terminal of described diode D1, the collector electrode of triode Q1, transient voltage suppressor TVS, one end of resistance R3, one end of electric capacity C1 and triode Q4 is connected on No. three nodes, the collector electrode of the other end of the positive terminal of described diode D2, the collector electrode of triode Q2, transient voltage suppressor TVS, one end of resistance R2, the other end of electric capacity C1 and triode Q6 is connected on No. four nodes, one end of the emitter of triode Q4, signal ground end SGND, the transmitting of triode Q6, one end of resistance R10 and resistance R13 is connected on No. five nodes, described relay combined floodgate end, one end of resistance R8, one end of resistance R9 are connected on No. six nodes, No. 3 ports of the other end of described resistance R5, the other end of resistance R10 and photoelectrical coupler OPT22 are connected on No. seven nodes, operate a switch end, one end of resistance R11, one end of resistance R12 of described relay is connected on No. eight nodes, the other end of described resistance R9, No. 2 ports of photoelectrical coupler OPT22, the other end of resistance R12, No. 2 ports of photoelectrical coupler OPT23 and electric wire earth terminal GND are connected on No. nine nodes, No. 3 ports of the other end of described resistance R7, the other end of resistance R13 and photoelectrical coupler OPT23 are connected on No. ten nodes, the base stage of triode Q1 is connected on the other end of resistance R2, and the base stage of triode Q2 is connected on the other end of resistance R3, the base stage of triode Q4 is connected on the emitter of triode Q3, and the collector electrode of triode Q3 is connected on one end of resistance R4, and the base stage of triode Q3 is connected on one end of resistance R5, and the other end of resistance R4 is connected on 5V supply terminals, the base stage of triode Q6 is connected on the emitter of triode Q5, and the collector electrode of triode Q5 is connected on one end of resistance R6, and the base stage of triode Q5 is connected on one end of resistance R7, and the other end of resistance R6 is connected on 5V supply terminals, the other end of resistance R8 is connected on No. 1 port of photoelectrical coupler OPT22, the other end of resistance R11 is connected on No. 1 port of photoelectrical coupler OPT23, No. 4 ports of photoelectrical coupler OPT22 are connected on 5V supply terminals, and No. 4 ports of photoelectrical coupler OPT23 are also connected on 5V supply terminals.

2. a kind of control relay circuit with isolation according to claim 1, is characterized in that, described triode Q1 and described triode Q2 is the triode of positive-negative-positive.

3. a kind of control relay circuit with isolation according to claim 1, is characterized in that, described triode Q3, described triode Q4, described triode Q5 and described triode Q6 are the triode of NPN type.