Short circuit and overcurrent fault self-locking protection circuit
By designing a short-circuit overcurrent fault self-locking protection circuit, and utilizing components such as current sensors and operational amplifiers, the circuit is automatically cut off, solving the problems of untimely response and non-adjustability of fuses. This achieves a fast and flexible protection mechanism, improving the safety and reliability of the equipment.
Patent Information
- Application Number
- CN202520218877.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-11
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2035-02-11
AI Technical Summary
In the existing technology, fuses as a short circuit or overcurrent protection method have problems such as low safety, time-consuming replacement and slow response, and the melting point cannot be adjusted.
A short-circuit overcurrent fault self-locking protection circuit was designed. It utilizes components such as a current sensor, operational amplifier, positive logic optocoupler relay, and power MOSFET to form a self-locking circuit. When the current exceeds the set value, the main circuit is automatically cut off through the feedback of the operational amplifier and the control of the optocoupler relay to protect the equipment.
It achieves a fast and flexible protection mechanism with a simple and low-cost structure. It can flexibly set the overcurrent point and protection speed to ensure the safe operation of the equipment and improve its reliability and stability.
Smart Images
Figure CN223599487U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of circuit protection, in particular to a short-circuit and over-current fault self-locking protection circuit. BACKGROUND
[0002] With the progress of science and technology, short-circuit and over-current are indispensable circuits in equipment, and short-circuit and over-current faults can cause great disasters to the equipment, so as to cause the system to be unable to work normally. In the circuit, a fuse is commonly used as a short-circuit or over-current protection mode, and this mode has three shortcomings: first, once the fuse is fused, it needs to be replaced, and in a more complex system, it takes a lot of time to disassemble and assemble; second, the fuse sometimes reacts slowly and cannot be fused in time to better protect the equipment; and third, the fusing point cannot be adjusted arbitrarily. CONTENT OF THE UTILITY MODEL
[0003] Therefore, the present application provides a short-circuit and over-current fault self-locking protection circuit, which at least partially solves the problems of low safety of the fuse and time-consuming disassembly and replacement in the prior art.
[0004] The present application provides a short-circuit and over-current fault self-locking protection circuit, which comprises a current sensor N1, an operational amplifier N2B, a positive logic optocoupler relay V2, a power MOS tube V4, a diode V1, a capacitor C1 and resistors, the resistors comprising a first resistor R1, a second resistor R2 and a third resistor R3, a VCC pin of the current sensor N1 is connected to an auxiliary source, a VOUT pin of the current sensor N1 is connected to the first resistor R1 and the second resistor R2 in sequence, an input positive terminal of the operational amplifier N2B is connected between the first resistor R1 and the second resistor R2, a VREF pin of the current sensor N1 is connected to an input negative terminal of the operational amplifier N2B, a GND terminal of the current sensor N1 is grounded, the capacitor C1 is connected in parallel across the second resistor R2 and located at the input positive terminal of the operational amplifier N2B, an output terminal of the operational amplifier N2B is fed back to the input positive terminal of the operational amplifier N2B through the third resistor R3 and the diode V1 connected in sequence, and the output terminal of the operational amplifier N2B is also connected to an input terminal of the positive logic optocoupler relay V2. The power MOS tube V4 is connected in series at a negative terminal of a loop, and an output terminal of the positive logic optocoupler relay V2 is connected to the power MOS tube V4.
[0005] According to a specific implementation manner of the present application, the resistors further comprise a fourth resistor R4, and the fourth resistor R4 is located between an output terminal of the positive logic optocoupler relay V2 and a first input terminal of the positive logic optocoupler relay V2.
[0006] According to a specific implementation manner of the present application, a second input terminal of the positive logic optocoupler relay V2 is grounded, and a first output terminal and a second output terminal of the positive logic optocoupler relay V2 are connected in parallel to a G pin and an S pin of the power MOS tube V4, respectively.
[0007] According to a specific implementation manner of the embodiment of the application, the circuit further comprises a voltage stabilizing tube V3 connected in parallel between the G pin and the S pin of the power MOS tube V4.
[0008] According to a specific implementation manner of the embodiment of the application, the circuit further comprises a fifth resistor R5, one end of the fifth resistor R5 being connected to the output positive terminal, and the other end of the fifth resistor R5 being connected to the voltage stabilizing tube V3.
[0009] Advantages:
[0010] The short-circuit overcurrent fault self-locking protection circuit in the embodiment of the application, when the current in the loop exceeds the set current, the output of the operational amplifier N2B is flipped to high level, and the high level voltage is fed back to the + terminal of the operational amplifier N2B, forming a self-locking circuit, and driving the positive logic photo-coupler relay V2 front end to conduct, and the output end is also conducted, and finally the voltage between the GS of the MOS tube V4 becomes low level, and the MOS tube V4 is turned off, so that the main loop is cut off, forming a self-locking type short-circuit overcurrent fault protection circuit, and the protection speed can be flexibly set through the capacitor C1, and the overcurrent point can be set by changing the resistance value of the second resistor R2, and whether to self-lock can be determined by adjusting the diode V1 and the voltage stabilizing tube R3. The method can be used for a protection mechanism when a large current in the device is cut off.
[0011] The circuit has the advantages of simple structure, low cost, flexible setting of reaction time and overcurrent point, and the like, and after a fault, the loop is disconnected, when the fault disappears, the circuit needs to be restarted, and the circuit can restore normal work. The safety of equipment operation and use is ensured, so that the reliability and stability of the product are improved. BRIEF DESCRIPTION OF DRAWINGS
[0012] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort.
[0013] Figure 1 The short-circuit overcurrent fault self-locking protection circuit according to an embodiment of the application. DETAILED DESCRIPTION
[0014] The embodiments of the application will be described in detail below with reference to the drawings.
[0015] Following, the embodiments of the present application are described through specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0016] It should be noted that the various aspects of the embodiments described below are within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the teachings herein one skilled in the art should appreciate that an aspect described herein can be implemented independently of any other aspects and that an aspect described herein can be implemented both as any number of software and / or hardware structures and as any number of processes and / or operations. For example, an aspect can be implemented as a software application, hardware application, firmware application, or a combination of any of the above.
[0017] It should also be noted that the figures provided in the following embodiments are only to illustrate the basic concepts of the present application in a schematic manner, and only show the components related to the present application in the figures, not drawn according to the number, shape and size of the components in actual implementation, and the shape, number and proportion of each component in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complex.
[0018] In addition, in the following description, specific details are provided in order to facilitate a thorough understanding of examples. However, one skilled in the art will understand that the aspects described can be practiced without these specific details.
[0019] The embodiments of the present application provide a short-circuit over-current fault self-locking protection circuit, which is described below with reference to Figure 1Detailed description is made. The circuit comprises a current sensor N1, an operational amplifier N2B, a positive logic optocoupler relay V2, a power MOS tube V4, a diode V1, a capacitor C1 and resistors including a first resistor R1, a second resistor R2 and a third resistor R3, a VCC pin of the current sensor N1 is connected to an auxiliary source, a VOUT pin of the current sensor N1 is connected to the first resistor R1 and the second resistor R2 in sequence, an input positive terminal of the operational amplifier N2B is connected between the first resistor R1 and the second resistor R2, a VREF pin of the current sensor N1 is connected to an input negative terminal of the operational amplifier N2B, a GND terminal of the current sensor N1 is grounded, the capacitor C1 is connected in parallel between the second resistor R2 and the input positive terminal of the operational amplifier N2B, an output terminal of the operational amplifier N2B is fed back to the input positive terminal of the operational amplifier N2B through the third resistor R3 and the diode V1 connected in sequence, the output terminal of the operational amplifier N2B is also connected to an input terminal of the positive logic optocoupler relay V2, the power MOS tube V4 is connected in series at a negative terminal of the loop, and an output terminal of the positive logic optocoupler relay V2 is connected to the power MOS tube V4.
[0020] Further, the resistors further comprise a fourth resistor R4, and the fourth resistor R4 is located between an output terminal of the positive logic optocoupler relay V2 and a first input terminal of the positive logic optocoupler relay V2.
[0021] Further, a second input terminal of the positive logic optocoupler relay V2 is grounded, and a first output terminal and a second output terminal of the positive logic optocoupler relay V2 are connected in parallel to a G pin and an S pin of the power MOS tube V4, respectively.
[0022] Further, the circuit further comprises a stabilizing tube V3, and the stabilizing tube V3 is connected in parallel between the G pin and the S pin of the power MOS tube V4.
[0023] Further, the circuit further comprises a fifth resistor R5, one end of the fifth resistor R5 is connected to an output positive terminal, and the other end of the fifth resistor R5 is connected to the stabilizing tube V3.
[0024] In specific implementation, the auxiliary source is +5V, which is a circuit independent of an input source, and the auxiliary source +5V is connected to an input negative terminal, which can be realized in multiple ways according to the use environment. The circuit comprises the current sensor N1, the operational amplifier N2B, the diode V1, the stabilizing tube V3, the positive logic optocoupler relay V2, the power MOS tube V4, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the capacitor C1 and the auxiliary source +5V.
[0025] The current in the loop is sampled by the current sensor N1 into a voltage value, the voltage value after sampling is divided by the first resistor R1 and the second resistor R2, the VREF (2.5V) of the current sensor N1 is connected to the input + end of the operational amplifier N2B, the 7 pin (VREF pin) of the current sensor N1 is directly connected to the input - end of the comparator as a reference of the operational amplifier N2B, the capacitor C1 is connected to the input + end of the operational amplifier N2B, the output pin of the operational amplifier N2B is fed back to the input + end of the operational amplifier N2B through the third resistor R3 and the diode V1 in series, the output end of the operational amplifier N2B is connected to the input 1 pin of the positive logic photo-coupler relay V2 through the current limiting resistor R4, the MOS tube V4 is connected in series to the negative end of the loop, the S pin of the MOS tube V4 is connected to the input negative end, the D pin of the MOS tube V4 is connected to the output negative end, the loop is connected in series through the current limiting resistor R5 and the stabilizing tube V3, one end of the third resistor R3 is connected to the input positive end, the stabilizing tube V3 is connected in parallel between the G pin and the S pin of the MOS tube V4, the output 4 pin and the output 3 pin of the positive logic photo-coupler relay V2 are connected in parallel to the G pin and the S pin of the MOS tube V4 respectively.
[0026] The working principle of the circuit of the application is as follows: after the input IN and IN_GND are powered by 5V, the input can be directly referenced as an auxiliary source in the circuit, when the current in the loop exceeds the set current, that is, the input + of the operational amplifier N2B exceeds 2.5V, the OUTB end of the operational amplifier N2B flips to high level 3.5V, the INB+ end of the operational amplifier N2B is continuously greater than 2.5V through the feedback resistor R3 and the diode V1, a self-locking loop of the OUTB end of the operational amplifier N2B continuously outputting 3.5V is formed, the input end of the positive logic photo-coupler relay V2 is turned on through the current limiting resistor R4, the output end of the positive logic photo-coupler relay V2 is turned on, the G and S ends of the MOS tube V4 are driven to turn off the voltage, and the D and S ends of the MOS tube V4 in the ground loop are disconnected, so as to achieve a protection method of disconnecting the main loop to prevent the fault in the equipment from further expanding. After the fault disappears, the equipment must be powered again to work normally again.
[0027] In one embodiment, if the self-locking function is not required in actual application, the diode V1 and the third resistor R3 can be removed to realize the corresponding function.
[0028] The embodiment of the application, when the current in the loop exceeds the set current, the operational amplifier N2B outputs a flip to high level, and feeds back the high level voltage to the + end of the operational amplifier N2B, forms a self-locking circuit, and drives the front end of the optocoupler V2 to turn on, the optocoupler V2 is a positive logic optocoupler, the output end thereof is also turned on, finally makes the voltage between the G and S pins of the MOS tube V4 become low level, turns off the MOS tube V4, thereby cutting off the main loop, forms a self-locking type short circuit overcurrent fault protection circuit, and the protection speed can be flexibly set through the capacitor C1, the overcurrent point can be set through changing the resistance value of the second resistor R2, and whether to self-lock can be determined through adjusting the diode V1 and the third resistor R3. The method can be used for cutting off a protection mechanism when a large current in equipment. The circuit has the advantages of simple structure, low cost, and flexible setting of the reaction time and the overcurrent point.
[0029] The above is merely a specific implementation of the application, but the protection scope of the application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered in the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.
Claims
1. A short-circuit overcurrent fault self-locking protection circuit, characterized in that, The circuit includes a current sensor N1, an operational amplifier N2B, a positive logic optocoupler relay V2, a power MOSFET V4, a diode V1, a capacitor C1, and resistors, including a first resistor R1, a second resistor R2, and a third resistor R3. The VCC pin of the current sensor N1 is connected to an auxiliary source, and the VOUT pin of the current sensor N1 is connected to the first resistor R1 and the second resistor R2 in sequence. The positive input terminal of the operational amplifier N2B is connected between the first resistor R1 and the second resistor R2. The VREF pin of the current sensor N1 is connected to the negative input terminal of the operational amplifier N2B. The GND terminal of the current sensor N1 is grounded. The capacitor C1 is connected in parallel across the second resistor R2 and is located at the positive input terminal of the operational amplifier N2B. The output terminal of the operational amplifier N2B is fed back to the positive input terminal of the operational amplifier N2B through the third resistor R3 and the diode V1 connected in series in sequence. The output terminal of the operational amplifier N2B is also connected to the input terminal of the positive logic optocoupler relay V2. The power MOSFET V4 is connected in series at the negative terminal of the circuit, and the output terminal of the positive logic optocoupler relay V2 is connected to the power MOSFET V4.
2. The short-circuit overcurrent fault self-locking protection circuit according to claim 1, characterized in that, The resistor also includes a fourth resistor R4, which is located between the output terminal of the positive logic optocoupler relay V2 and the first input terminal of the positive logic optocoupler relay V2.
3. The short-circuit overcurrent fault self-locking protection circuit according to claim 2, characterized in that, The second input terminal of the positive logic optocoupler relay V2 is grounded, and the first and second output terminals of the positive logic optocoupler relay V2 are connected in parallel to the G and S pins of the power MOSFET V4, respectively.
4. The short-circuit overcurrent fault self-locking protection circuit according to claim 1, characterized in that, The circuit also includes a Zener diode V3, which is connected in parallel between the gate (G) and source (S) pins of the power MOSFET V4.
5. The short-circuit overcurrent fault self-locking protection circuit according to claim 4, characterized in that, The circuit also includes a fifth resistor R5, one end of which is connected to the positive output terminal, and the other end of which is connected to the Zener diode V3.