Reliable isolation control circuit

Abstract

The utility model relates to the technical field of power supply circuits, in particular to a reliable isolation control circuit, which comprises an isolation optocoupler U1, a high-voltage input control module, a voltage division module, a voltage stabilizing diode D2, a diode D1, a switching tube Q2, a first ground end GND and a second ground end VNC. The reliable isolation control circuit provided by the utility model has an isolation design, the negative electrode of the power supply is connected to the switch tube Q2, and the switch-on and switch-off of the switch tube Q2 are controlled through the isolation optocoupler U1 and the high-voltage input control module, so that whether the power supply is output or not is controlled. The utility model has the advantages of simple structure principle, greatly enhanced reliability and low cost, and is suitable for most switches, thereby ensuring the use safety and stability of the switches.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuits, in particular to a reliable isolation control circuit. Background Art

[0002] With the continuous development of network communication technology, POE switches, as an important network connection device, are widely used in various scenarios. POE switches can not only transmit data but also power terminal devices, simplifying the wiring process and improving the flexibility of the system. However, although there are various types of POE switches on the market, products with effective isolation control functions are rare.

[0003] The isolation control function is of great significance for preventing signal interference, protecting device safety, and ensuring the stable operation of the system. In some application scenarios, such as industrial environments, medical facilities, or data centers where high security requirements are imposed, the isolation control function is particularly crucial. Traditional isolation control schemes often rely on complex hardware designs and expensive components, which not only increase the design difficulty of the product but also raise the cost of the final product.

[0004] Currently, for the isolation design applied to POE switches, the existing isolation control circuit designs are usually complex and require professional electronic engineers for elaborate design and debugging. Moreover, due to the use of special materials and technologies, the cost of the entire switch increases significantly. At the same time, the complex circuit design may introduce more fault points, thus affecting the stability of the overall system.

[0005] Due to the high cost, in non-essential situations, switches with isolation functions are generally not used. That is, switches in ordinary situations do not have isolation designs. POE switches without isolation control have certain risks during use and may cause problems such as load damage and system instability. Summary of the Invention

[0006] The utility model provides a reliable isolation control circuit for the problems of the prior art. The circuit has a simple structure and low cost, can be applied to switches in ordinary situations, and protects the use of the switch and the load.

[0007] To solve the above technical problems, the present utility model adopts the following technical solutions: A reliable isolation control circuit includes an isolation optocoupler U1, a high-voltage input control module, a voltage division module, a zener diode D2, a diode D1, a switching transistor Q2, a first ground terminal GND, and a second ground terminal V_N_C. One input terminal of the isolation optocoupler U1 is connected to an external control terminal, the other input terminal of the isolation optocoupler U1 is connected to the first ground terminal GND, one switching terminal of the isolation optocoupler U1 is connected to the second ground terminal V_N_C, the other switching terminal of the isolation optocoupler U1 is connected to the control terminal of the high-voltage input control module, the input terminal of the high-voltage input control module is connected to a high voltage, the output terminal of the high-voltage input control module is connected to the input terminal of the voltage division module, the output terminal of the voltage division module is connected to the cathode of the zener diode D2, the anode of the zener diode D2 is connected to the second bottom end, the anode of the diode D1 is connected to the output terminal of the voltage division module, the anode of the diode D1 is connected to the control terminal of the switching transistor Q2, one switching terminal of the switching transistor Q2 is connected to the negative pole of an external power supply, and the other switching terminal of the switching transistor Q2 is connected to the second ground terminal V_N_C.

[0008] Preferably, the high-voltage input control module includes a switching transistor Q1 and a resistor R1. The control terminal of the switching transistor Q1 is connected to the other switching terminal of the isolation optocoupler U1 through one end of the resistor R1, the other end of the resistor R1 is connected to an external high voltage, one switching terminal of the switching transistor Q1 is connected to the external high voltage, and the other switching terminal of the switching transistor Q1 is connected to the input terminal of the voltage division module.

[0009] Preferably, the voltage division module includes a resistor R2 and a resistor R3. One end of the resistor R2 is connected to the other switching terminal of the switching transistor Q1, the other end of the resistor R2 is connected to the second ground terminal V_N_C through the resistor R3, and the other end of the resistor R2 is connected to the cathode of the zener diode D2.

[0010] Preferably, it further includes a current-limiting resistor R5. One input terminal of the isolation optocoupler U1 is connected to an external control signal through the current-limiting resistor R5.

[0011] Preferably, it further includes a resistor R4. One end of the resistor R4 is connected to the second ground terminal V_N_C, and the other end of the resistor R4 is connected to the control terminal of the switching transistor Q2.

[0012] Preferably, the switching transistor Q2 is an NMOS transistor.

[0013] Preferably, the switching transistor Q1 is a PNP triode.

[0014] The beneficial effects of the present utility model:

[0015] A reliable isolation control circuit provided by the utility model has two grounds and an isolation design. The negative pole of the power supply is connected to the switching transistor Q2, and then the conduction and disconnection of the switching transistor Q2 are controlled through an isolation optocoupler U1 and a high-voltage input control module, so as to control whether the power supply has an output. The structural principle of the utility model is simple, the reliability is greatly enhanced, and the cost is low. It is applicable to most switches, thus ensuring the safe and stable use of the switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is the circuit schematic diagram of the utility model.

[0017] In Figure 1 the reference numerals in the drawings include:

[0018] 1 - high-voltage input control module, 2 - voltage dividing module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] For the convenience of understanding by those skilled in the art, the utility model will be further described below in conjunction with the embodiments and the drawings. The content mentioned in the embodiments does not limit the utility model. The following describes the utility model in detail with reference to the drawings.

[0020] A reliable isolation control circuit provided by this embodiment, as Figure 1 , includes an isolation optocoupler U1, a high-voltage input control module 1, a voltage dividing module 2, a zener diode D2, a diode D1, a switching transistor Q2, a first ground terminal GND, and a second ground terminal V_N_C. One input terminal of the isolation optocoupler U1 is connected to an external control signal, the other input terminal of the isolation optocoupler U1 is connected to the first ground terminal GND, one switching terminal of the isolation optocoupler U1 is connected to the second ground terminal V_N_C, the other switching terminal of the isolation optocoupler U1 is connected to the control terminal of the high-voltage input control module 1, the input terminal of the high-voltage input control module 1 is connected to a high voltage, the output terminal of the high-voltage input control module 1 is connected to the input terminal of the voltage dividing module 2, the output terminal of the voltage dividing module 2 is connected to the cathode of the zener diode D2, the anode of the zener diode D2 is connected to the second bottom end, the anode of the diode D1 is connected to the output terminal of the voltage dividing module 2, the anode of the diode D1 is connected to the control terminal of the switching transistor Q2, one switching terminal of the switching transistor Q2 is connected to the negative pole of an external power supply, and the other switching terminal of the switching transistor Q2 is connected to the second ground terminal V_N_C.

[0021] Among them, the high-voltage input control module 1 includes a switching transistor Q1 and a resistor R1. The control terminal of the switching transistor Q1 is connected to the other switching terminal of the isolation optocoupler U1 through one end of the resistor R1. The other end of the resistor R1 is connected to an external high voltage. One switching terminal of the switching transistor Q1 is connected to the external high voltage, and the other switching terminal of the switching transistor Q1 is connected to the input terminal of the voltage dividing module 2; the voltage dividing module 2 includes a resistor R2 and a resistor R3. One end of the resistor R2 is connected to the other switching terminal of the switching transistor Q1. The other end of the resistor R2 is connected to the second ground terminal V_N_C through the resistor R3, and the other end of the resistor R2 is connected to the cathode of the zener diode D2; a current limiting resistor R5 and a resistor R4 are also provided. The circuit connection method of this embodiment is as Figure 1 shown.

[0022] As Figure 1 shown, the specific working principle of this embodiment is:

[0023] 1. When it is necessary to control the switching transistor Q2 of the NMOS to turn on so that the power supply starts to supply power, first, a high-level signal of 3.3V or 5V needs to be given from an external control terminal to the isolation optocoupler U1; among them, this high-level signal can be set by software, that is, passively triggered. For example, in the case of power redundancy, when there is a problem with the other power supply, the system automatically switches to the other power supply; it can also be sent manually in real time; when the signal reaches pin 1 of the isolation optocoupler U1, since pin 2 of the isolation optocoupler U1 is grounded, and there is an equivalent built-in light-emitting diode in series between pins 1 and 2 of the isolation optocoupler itself. After the high-level signal reaches pin 1, the built-in light-emitting diode in the isolation optocoupler starts to emit light. Immediately after the opposite end of the optocoupler receives the light source, it starts to work. Pins 3 and 4 of the isolation optocoupler U1 are equivalent to an NPN transistor, and the received light source is the base of the transistor. When the light source is received, it is similar to the situation where there is current flowing through the base and the emitter, and the emitter is forward-biased. Pins 3 and 4 of the isolation optocoupler U1 are turned on. Pin 4 of the isolation optocoupler U1 is connected in parallel with the switching transistor Q1, that is, the PNP transistor, through a resistor R1;

[0024] 2. After pins 3 and 4 of the isolation optocoupler U1 are turned on, the resistor connected in series with pin 4 of the isolation optocoupler U1 is connected to the high voltage and is connected in parallel with the base of the switching transistor Q1. The resistor R1 is used to provide a bias voltage for the switching transistor Q1. By default, the switching transistor Q1 is in a cut-off state. At this time, after pins 3 and 4 of the isolation optocoupler U1 are turned on, the base of the switching transistor Q1 is pulled down to a low level, and the switching transistor Q1 is in an amplification state. The switching transistor Q1 is turned on, and the high voltage is applied to the resistor R2 connected in series with the collector of the switching transistor Q1;

[0025] 3. Resistor R2 and resistor R3 are connected in series and connected to the ground, and are connected to the MOS gate controlling the negative pole of the power supply through a diode D1. When there is a high voltage on resistor R2, by selecting appropriate resistance values for resistor R2 and resistor R3, the voltage division between them is 10 - 12V (the fully - on voltage of the MOS transistor). Resistor R3 is connected in parallel with the zener diode D2 to protect the gate of the switching transistor Q2. At this time, a stable driving voltage of 12V is applied to the gate of the switching transistor Q2 to turn it on, and the power supply starts to supply power. Among them, resistor R4 is used to connect a resistor in parallel to the ground at the gate when the switching transistor Q2 is not turned on to keep the gate at a low level.

[0026] Therefore, the isolation control circuit of this embodiment has a simple structural principle and an isolation design. Electrical isolation is achieved through the first ground terminal GND and the second ground terminal V_N_C. The negative pole of the power supply is connected to the switching transistor Q2, and the on - off of the switching transistor Q2 is controlled through the isolation optocoupler U1 and the high - voltage input control module 1, that is, the power supply output is controlled by controlling the switch of the switching transistor Q2. The structural principle of the present invention is simple, the reliability is greatly enhanced, the cost is low, and it is applicable to most switches. That is, without sacrificing functionality and safety, a more economical and efficient POE switch product design is realized, thereby reducing the use risk and protecting the load from damage, thus ensuring the safe and stable use of the switch.

[0027] The above are only preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention is disclosed above in preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, when making some changes or modifications using the above - disclosed technical content as equivalent change equivalent embodiments, but as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical meaning of the present invention shall fall within the scope of the technical solution of the present invention.

Claims

1. A reliable isolation control circuit, characterized in that: It includes an isolation optocoupler U1, a high-voltage input control module, a voltage divider module, a voltage regulator diode D2, a diode D1, a switch tube Q2, a first ground terminal GND and a second ground terminal V_N_C, wherein one input terminal of the isolation optocoupler U1 is connected to an external control terminal, the other input terminal of the isolation optocoupler U1 is connected to the first ground terminal GND, one switch terminal of the isolation optocoupler U1 is connected to the second ground terminal V_N_C, the other switch terminal of the isolation optocoupler U1 is connected to the control terminal of the high-voltage input control module, the input terminal of the high-voltage input control module is connected to a high voltage, the output terminal of the high-voltage input control module is connected to the input terminal of the voltage divider module, the output terminal of the voltage divider module is connected to the cathode of the voltage regulator diode D2, the anode of the voltage regulator diode D2 is linked to the second bottom terminal, the anode of the diode D1 is connected to the output terminal of the voltage divider module, the anode of the diode D1 is connected to the control terminal of the switch tube Q2, one switch terminal of the switch tube Q2 is connected to the negative electrode of the external power supply, and the other switch terminal of the switch tube Q2 is connected to the second ground terminal V_N_C.

2. A reliable isolation control circuit according to claim 1, characterized in that: The high-voltage input control module includes a switch tube Q1 and a resistor R1. The control end of the switch tube Q1 is connected to the other switch end of the isolation optocoupler U1 through one end of the resistor R1. The other end of the resistor R1 is connected to an external high voltage. One switch end of the switch tube Q1 is connected to the external high voltage, and the other switch end of the switch tube Q1 is connected to the input end of the voltage divider module.

3. A reliable isolation control circuit according to claim 2, characterized in that: The voltage divider module includes a resistor R2 and a resistor R3, one end of the resistor R2 is connected to the other switch end of the switch tube Q1, the other end of the resistor R2 is connected to the second ground end V_N_C through the resistor R3, and the other end of the resistor R2 is connected to the cathode of the voltage regulator diode D2.

4. A reliable isolation control circuit according to claim 1, characterized in that: A current limiting resistor R5 is also included, and an input end of the isolation optical coupler U1 is connected to an external control signal through the current limiting resistor R5.

5. A reliable isolation control circuit according to claim 1, characterized in that: A resistor R4 is also included. One end of the resistor R4 is connected to the second ground end V_N_C, and the other end of the resistor R4 is connected to the control end of the switch tube Q2.

6. A reliable isolation control circuit according to claim 1, characterized in that: The switch tube Q2 is an NMOS tube.

7. A reliable isolation control circuit according to claim 2, characterized in that: The switch tube Q1 is a PNP transistor.

Images