CN219937933U

CN219937933U - Output short-circuit protection circuit

Info

Publication number: CN219937933U
Application number: CN202223428201.0U
Authority: CN
Inventors: 肖俊承; 王一龙; 石从怀; 田卫红; 廖日云
Original assignee: Foshan Yigeer Electronics Co ltd; Eaglerise Electric and Electronic China Co Ltd; Foshan Shunde Eaglerise Electric Power Technology Co Ltd; Jian Eaglerise Electric Co Ltd; Jian Eaglerise Magnetic Technology Co Ltd; Jiangxi Eaglerise Digital Energy Technology Co Ltd
Current assignee: Foshan Yigeer Electronics Co ltd; Eaglerise Electric and Electronic China Co Ltd; Foshan Shunde Eaglerise Electric Power Technology Co Ltd; Jian Eaglerise Electric Co Ltd; Jian Eaglerise Magnetic Technology Co Ltd; Jiangxi Eaglerise Digital Energy Technology Co Ltd
Priority date: 2022-12-20
Filing date: 2022-12-20
Publication date: 2023-10-31
Anticipated expiration: 2032-12-20

Abstract

The utility model discloses an output short-circuit protection circuit which comprises a transformer T1, a rectifying and filtering module and a load module, wherein a primary feedback module, a current limiting module, an optical coupler isolation module, a blocking module and a switching tube Q1; the primary feedback module comprises diodes D2 and D3, a switch tube Q3, a resistor R13, a first feedback branch and a second feedback branch, the current limiting module comprises a resistor R2 and an optocoupler light emitting diode U1A, the optocoupler isolation module comprises a capacitor C2 and an optocoupler phototriode U1B, the current limiting module comprises a resistor R2 and an optocoupler light emitting diode U1A, and the optocoupler isolation module comprises a capacitor C2 and an optocoupler phototriode U1B. The output short-circuit protection circuit can avoid damage to the output short-circuit protection circuit caused by short-circuit current when playing a role in output short-circuit protection, and can be automatically put into use again after short-circuit fault repair.

Description

Output short-circuit protection circuit

Technical Field

The utility model relates to the technical field of body state detection equipment, in particular to an output short-circuit protection circuit.

Background

A short circuit refers to an operating condition in which two points in the circuit are directly connected by a conductor with negligible resistance. During operation of the power supply, there are often many uncontrollable factors that cause output shorts, which can have serious consequences for the load and the power supply. Because of the large short-circuit current generated during short-circuit, the electric power effect and the thermal effect generated by the short-circuit current can cause the damage to the fault equipment and other equipment in the short-circuit loop. Short circuits may occur at any point across the load or at any point on the line, and may also occur within the power supply or load. If a short circuit occurs at two ends of the power supply, only a small internal resistance of the power supply exists in the loop, so that a large short circuit current can be formed, and the circuit is damaged. Therefore, the power short circuit is a serious fault and should be avoided as much as possible. However, a "partial short circuit (short circuit)" employed in a circuit for achieving a specific purpose cannot be said to be a fault. To prevent the hazard of short-circuit faults from expanding, fuses or automatic circuit breakers are usually connected in the circuit for protection. However, because the generated short-circuit current is very large, the fuse which is connected into the fuse or the automatic breaker is often disconnected or a switching tube in the fuse is broken, and the fuse can be continuously used after being replaced or repaired, so that the fuse cannot be automatically put into use again after the short-circuit fault is repaired.

Disclosure of Invention

In view of the above-mentioned drawbacks, the present utility model aims to provide an output short-circuit protection circuit, which can prevent the short-circuit current from damaging itself while protecting the output short-circuit, and can be automatically put into use again after the short-circuit fault is repaired.

To achieve the purpose, the utility model adopts the following technical scheme:

the output short-circuit protection circuit comprises a transformer T1, a rectifying and filtering module, a load module, a primary feedback module, a current limiting module, an optical coupler isolation module, a blocking module and a switching tube Q1, wherein the input end of the rectifying and filtering module is electrically connected with a secondary winding of the transformer T1, and the output end of the rectifying and filtering module is electrically connected with the input end of the load module;

the primary feedback module comprises diodes D2 and D3, a switch tube Q3, a resistor R13, a first feedback branch and a second feedback branch, wherein the transformer T1 is provided with a first primary winding and a second primary winding, the first primary winding is used for supplying power, the positive electrode of the diode D3 is electrically connected with one end of the second primary winding of the transformer T1, the other end of the second primary winding of the transformer T1 is grounded, the negative electrode of the diode D3, the input end of the first feedback branch and the input end of the second feedback branch are electrically connected, the output end of the first feedback branch is electrically connected with the control end of the switch tube Q3, the output end of the second feedback branch is electrically connected with the input end of the switch tube Q3, the output end of the switch tube Q3 is electrically connected with the positive electrode of the diode D2, the negative electrode of the switch tube Q1 is electrically connected with one end of the resistor R13, and the other end of the resistor R13 is grounded; the input end of the switching tube Q1 is grounded, and the output end of the switching tube Q1 is electrically connected with the load module;

the current limiting module comprises a resistor R2 and a light emitting diode U1A of an optocoupler, the optocoupler isolation module comprises a capacitor C2 and a phototriode U1B of the optocoupler, one end of the resistor R2, one end of the capacitor C2, the input end of the phototriode U1B of the optocoupler and the output end of the rectifying and filtering module are electrically connected, the other end of the resistor R2 is electrically connected with an anode of the light emitting diode U1A of the optocoupler, a cathode of the light emitting diode U1A of the optocoupler and the other end of the capacitor C2 are grounded, and the output end of the phototriode U1B of the optocoupler is electrically connected with a control end of the switching tube Q1;

the blocking module comprises resistors R14 and R15 and a switch tube Q4, the resistor R14 and the resistor R15 are connected in series and then connected with a capacitor C2 in parallel, a control end of the switch tube Q4 is electrically connected with one end of the capacitor C2 through the resistor R14, an input end of the switch tube Q4 is electrically connected with a control end of the switch tube Q3 through the first feedback branch, and an output end of the switch tube Q4 is grounded.

Preferably, the device further comprises a linear voltage stabilizing module, wherein the input end of the linear voltage stabilizing module is electrically connected with the output end of the rectifying and filtering module, and the output end of the linear voltage stabilizing module, one end of the capacitor C2 and the input end of the phototriode U1B of the optocoupler are electrically connected.

Preferably, the linear voltage stabilizing module comprises a resistor R6, R7, R8, a capacitor C1, a voltage stabilizing diode DZ1 and a switching tube Q2, one end of the resistor R6 is electrically connected with the output end of the rectifying and filtering module, the other end of the resistor R6 is electrically connected with one end of the resistor R7, the other end of the resistor R7, the input end of the switching tube Q2, one end of the capacitor C1 and one end of the resistor R8 are electrically connected, the other end of the resistor R8, the control end of the switching tube Q2 and the negative electrode of the voltage stabilizing diode DZ1 are electrically connected, the output end of the switching tube Q2, one end of the capacitor C2 and the input end of the photo transistor U1B of the optocoupler are electrically connected, and the positive electrode of the voltage stabilizing diode DZ1 and the other end of the capacitor C1 are grounded.

Preferably, the circuit breaker further comprises a short circuit reminding module, wherein the short circuit reminding module is connected with the switching tube Q1 in series, and the short circuit reminding module is used for indicating the on-off of the switching tube Q1.

Preferably, the short-circuit reminding module comprises a resistor R3 and a light emitting diode LED1, one end of the resistor R3 is electrically connected with the input end of the switching tube Q1, the other end of the resistor R3 is electrically connected with the anode of the light emitting diode LED1, and the cathode of the light emitting diode LED1 is electrically connected with the output end of the switching tube Q1.

Preferably, the rectifying and filtering module includes a polar capacitor CE1, CE2, CE3 and a diode D1, where an anode of the diode D1 is electrically connected to a secondary winding of the transformer T1, an anode of the diode D1 is used as an input end of the rectifying and filtering module, and a cathode of the diode D1, an anode of the polar capacitor CE2 and an anode of the polar capacitor CE3 are electrically connected, and a cathode of the polar capacitor CE1, an anode of the polar capacitor CE2 and an anode of the polar capacitor CE3 are all grounded;

the cathode of the diode D1 is used as the output end of the rectifying and filtering module.

Preferably, the first feedback branch comprises resistors R9, R10, R16, and the resistors R9, R10, R16 are sequentially connected in series between the negative electrode of the diode D3 and the control end of the switching tube Q3;

the input end of the switching tube Q4 is electrically connected with the control end of the switching tube Q3 through a resistor R16.

Preferably, the second feedback branch comprises resistors R11, R12, and the resistors R11, R12 are sequentially connected in series between the cathode of the diode D3 and the input terminal of the switching tube Q3.

Preferably, the load module includes a resistor R1, a positive OUTPUT port output+ and a negative OUTPUT port OUTPUT-, one end of the resistor R1, the positive OUTPUT port output+ and the OUTPUT end of the rectifying and filtering module are electrically connected, the other end of the resistor R1 is electrically connected with the input end of the switching tube Q1, and the negative OUTPUT port OUTPUT is electrically connected with the OUTPUT end of the switching tube Q1.

Preferably, the current limiting module further comprises resistors R4 and R5, wherein two ends of the resistor R4 are electrically connected between the control end of the switching tube Q1 and the cathode of the light emitting diode LED 1;

the resistor R5 is connected in parallel with the light-emitting diode U1A of the optocoupler.

The technical scheme has the following advantages or beneficial effects:

the output short-circuit protection circuit controls the on-off of the switching tube Q1 by the optocoupler, can rapidly turn off the switching tube Q1 to play a role in output short-circuit protection when in short-circuit, and can prevent the switching tube Q1 from being broken down by short-circuit current due to the isolation effect of the optocoupler when in short-circuit, so that the damage of the short-circuit current to the switching tube Q1 is avoided, and the switching tube Q1 can be automatically put into use again after the short-circuit fault is repaired.

Drawings

Fig. 1 is a schematic block diagram of one embodiment of the present utility model.

Fig. 2 is a schematic diagram of an output short-circuit protection circuit according to one embodiment of the present utility model.

Wherein: a transformer T1; a rectifying and filtering module 1; a load module 2; a primary feedback module 3; a current limiting module 4; an optocoupler isolation module 5; a linear voltage stabilizing module 6; a blocking module 7; a short circuit alert module 8.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

As shown in fig. 1-2, the output short-circuit protection circuit of the embodiment comprises a transformer T1, a rectifying and filtering module 1 and a load module 2, wherein the input end of the rectifying and filtering module 1 is electrically connected with the secondary winding of the transformer T1, and the output end of the rectifying and filtering module 1 is electrically connected with the input end of the load module 2; the device also comprises a primary feedback module 3, a current limiting module 4, an optical coupler isolation module 5, a blocking module 7 and a switching tube Q1;

the primary feedback module 3 comprises diodes D2 and D3, a switching tube Q3, a resistor R13, a first feedback branch and a second feedback branch, the transformer T1 is provided with a first primary winding and a second primary winding, the first primary winding is used for supplying power, the anode of the diode D3 is electrically connected with one end of the second primary winding of the transformer T1, the other end of the second primary winding of the transformer T1 is grounded, the cathode of the diode D3, the input end of the first feedback branch and the input end of the second feedback branch are electrically connected, the output end of the first feedback branch is electrically connected with the control end of the switching tube Q3, the output end of the second feedback branch is electrically connected with the input end of the switching tube Q3, the output end of the switching tube Q3 is electrically connected with the anode of the diode D2, the cathode of the diode D2, the control end of the switching tube Q1 and one end of the resistor R13 are electrically connected, and the other end of the resistor R13 is grounded; the input end of the switching tube Q1 is grounded, and the output end of the switching tube Q1 is electrically connected with the load module 2;

the current limiting module 4 comprises a resistor R2 and a light emitting diode U1A of the optocoupler, the optocoupler isolation module 5 comprises a capacitor C2 and a phototriode U1B of the optocoupler, one end of the resistor R2, one end of the capacitor C2, the input end of the phototriode U1B of the optocoupler and the output end of the rectifying and filtering module 1 are electrically connected, the other end of the resistor R2 is electrically connected with the anode of the light emitting diode U1A of the optocoupler, the cathode of the light emitting diode U1A of the optocoupler and the other end of the capacitor C2 are grounded, and the output end of the phototriode U1B of the optocoupler is electrically connected with the control end of the switching tube Q1;

the blocking module 7 comprises resistors R14 and R15 and a switching tube Q4, the resistor R14 and the resistor R15 are connected in series and then connected with a capacitor C2 in parallel, the control end of the switching tube Q4 is electrically connected with one end of the capacitor C2 through the resistor R14, the input end of the switching tube Q4 is electrically connected with the control end of the switching tube Q3 through a first feedback branch, and the output end of the switching tube Q4 is grounded.

The output short-circuit protection circuit inputs power through the transformer T1, the output voltage becomes smoother after rectifying and filtering by the rectifying and filtering module 1, and the output voltage can be more stable by the load module 2, and the voltage can be output outwards only by starting the switching tube Q1. The primary feedback module 3 is required to drive the switching tube Q1, specifically: the method comprises the steps that voltage is output to a diode D3 through a second primary winding of a transformer T1, and the voltage is rectified through the diode D3 and then is conducted through a first feedback branch circuit driving a switching tube Q3; after the switching tube Q3 is conducted, the output voltage is divided to the control end of the switching tube Q1 through the second feedback branch and the resistor R13, so that the switching tube Q1 is conducted, and the whole circuit has an output voltage load and starts to work.

At the moment when the switching tube Q1 is conducted, a part of current is limited by the R2 resistor of the current limiting module 4 to supply power to the light emitting diode U1A of the optocoupler, so that the light emitting diode U1A of the optocoupler works, the phototriode U1B of the optocoupler is conducted, and the voltage at two ends of the capacitor C2 is transmitted to the control end of the switching tube Q1. When the output short-circuit protection circuit works normally, under the control action of the light emitting diode U1A of the optocoupler, the phototriode U1B of the optocoupler is continuously conducted, the capacitor C2 can continuously provide driving voltage for the control end of the switching tube Q1, and at the moment, the diode D2 can play a role in preventing reverse, so that the voltage of the control end of the switching tube Q1 can be prevented from being pulled off by the switching tube Q3.

Meanwhile, the voltage at two ends of the capacitor C2 starts the switching tube Q4 through the voltage division of the resistors R14 and R15, the voltage at the control end of the switching tube Q3 is pulled to 0 through the first feedback branch circuit at this time, so that the switching tube Q3 is promoted to be turned off, the switching tube Q3 at this time is not turned on any more, and the driving voltage at the control end of the switching tube Q1 is provided by the voltage at two ends of the capacitor C2, so that the effect of controlling the on-off of the switching tube Q1 by the optocoupler is achieved.

Therefore, when the load is short-circuited, i.e. the two points A, B in fig. 1 or 2 are short-circuited, the voltage at the two points A, B is close to 0 at the moment of the short-circuit, the light emitting diode U1A of the optocoupler is connected to the two points ab, if the light emitting diode U1A of the optocoupler has no voltage, the optocoupler stops working, and the phototransistor U1B of the optocoupler is also cut off. After the phototriode U1B of the optocoupler is cut off, the control end of the switching tube Q1 loses the driving voltage, the parasitic capacitance of the control end of the switching tube Q1 can be discharged due to the load module 2, the switching tube Q1 is cut off immediately, namely, a circuit is disconnected, so that the whole circuit enters a protection state, and short-circuit protection is realized.

The optocoupler can realize the effect of controlling isolation, and when short circuit occurs, short circuit current cannot break through the switching tube Q1 due to the isolation effect of the optocoupler. Therefore, after the short circuit is relieved, the switching tube Q1 can be put into use again, namely the working process is repeated, the voltage for starting the switching tube Q1 is provided by the second primary winding of the transformer T1 again, the optical coupler is used for controlling the switching tube Q1 to be conducted, the output is carried out again, the effect that the circuit is automatically put into use again after the short circuit fault is relieved is achieved, and other operations are not needed. The output short-circuit protection circuit can rapidly turn off the switching tube Q1 to well protect an external load when in short circuit, and can be automatically put into use again after the short-circuit fault is relieved, so that the circuit cost is low and the service life is long.

Further, the device further comprises a linear voltage stabilizing module 6, wherein the input end of the linear voltage stabilizing module 6 is electrically connected with the output end of the rectifying and filtering module 1, and the output end of the linear voltage stabilizing module 6, one end of the capacitor C2 and the input end of the phototriode U1B of the optocoupler are electrically connected. The linear voltage stabilizing module 6 can provide a stable voltage to two ends of the capacitor C2.

The method comprises the following steps: the linear voltage stabilizing module 6 comprises a resistor R6, R7, R8, a capacitor C1, a voltage stabilizing diode DZ1 and a switch tube Q2, one end of the resistor R6 is electrically connected with the output end of the rectifying and filtering module 1, the other end of the resistor R6 is electrically connected with one end of the resistor R7, the other end of the resistor R7, the input end of the switch tube Q2, one end of the capacitor C1 and one end of the resistor R8 are electrically connected, the other end of the resistor R8, the control end of the switch tube Q2 and the negative electrode of the voltage stabilizing diode DZ1 are electrically connected, the output end of the switch tube Q2, one end of the capacitor C2 and the input end of the phototriode U1B of the optocoupler are electrically connected, and the positive electrode of the voltage stabilizing diode DZ1 and the other end of the capacitor C1 are grounded.

Therefore, under the linear voltage stabilizing effect of the voltage stabilizing diode DZ1 and the switching tube Q2, the two ends of the capacitor C2 stabilize the output voltage, and the switching tube Q1 is continuously and stably driven to be conducted when the circuit works normally. The linear voltage stabilizing module 6 consists of resistors R6, R7 and R8, a capacitor C1, a voltage stabilizing diode DZ1 and a switching tube Q2, and has low price and high cost performance.

Optionally, the circuit breaker further comprises a short circuit reminding module 8, the short circuit reminding module 8 is connected with the switching tube Q1 in series, and the short circuit reminding module 8 is used for indicating the on-off state of the switching tube Q1. Therefore, the circuit is automatically protected, and the user is reminded of short circuit, so that the user can solve the short circuit problem as soon as possible.

In some embodiments, the short-circuit reminding module 8 includes a resistor R3 and a light emitting diode LED1, one end of the resistor R3 is electrically connected to the input end of the switching tube Q1, the other end of the resistor R3 is electrically connected to the anode of the light emitting diode LED1, and the cathode of the light emitting diode LED1 is electrically connected to the output end of the switching tube Q1. When a short circuit occurs, the switching tube Q1 is disconnected, and the parasitic capacitance at the control end of the switching tube Q1 discharges, so that the light-emitting diode LED1 emits light to remind a user of the short circuit; when the normal work or the short circuit problem is solved, the switching tube Q1 is turned on, the light emitting diode LED1 is turned off, and the short circuit fault is indicated to be removed by a user; so that it can be simply judged whether the short-circuit problem is eliminated by the light emitting diode LED 1.

In some embodiments, the rectifying and filtering module 1 includes a polar capacitor CE1, CE2, CE3 and a diode D1, where an anode of the diode D1 is electrically connected to a secondary winding of the transformer T1, and an anode of the diode D1 is used as an input terminal of the rectifying and filtering module 1, and a cathode of the diode D1, an anode of the polar capacitor CE2 and an anode of the polar capacitor CE3 are electrically connected, and a cathode of the polar capacitor CE1, an anode of the polar capacitor CE2 and an anode of the polar capacitor CE3 are all grounded; the cathode of the diode D1 is used as the output end of the rectifying and filtering module 1. The diode D1 performs a rectifying function, and the polar capacitors CE1, CE2, CE3 perform a filtering function, so that the output voltage is smoother. The polar capacitors CE1, CE2, CE3 may be aluminum electrolytic capacitors.

Further, the first feedback branch includes resistors R9, R10, R16, where the resistors R9, R10, R16 are sequentially connected in series between the negative electrode of the diode D3 and the control end of the switching tube Q3; the input end of the switching tube Q4 is electrically connected with the control end of the switching tube Q3 through a resistor R16.

Therefore, when the primary feedback module 3 drives the switching tube Q1 to start, the voltage rectified by the diode D3 drives the switching tube Q3 to be conducted through the resistors R9, R10 and R16.

After the switching tube Q4 is turned on, the voltage at the control end of the switching tube Q3 is pulled to 0 through the resistor R16, so that the GS voltage of the switching tube Q3 is a negative voltage, and the switching tube Q3 is turned off.

More specifically, the second feedback branch includes resistors R11, R12, and the resistors R11, R12 are sequentially connected in series between the cathode of the diode D3 and the input terminal of the switching tube Q3. Thus, after the switching tube Q3 is turned on, the output voltage is divided to the control end of the switching tube Q1 through the resistors R11, R12, the diode D3 and the resistor R13, so that the switching tube Q1 is turned on.

Optionally, the load module 2 includes a resistor R1, a positive OUTPUT port output+ and a negative OUTPUT port OUTPUT-, where one end of the resistor R1, the positive OUTPUT port output+ and the OUTPUT end of the rectifying and filtering module 1 are electrically connected, the other end of the resistor R1 is electrically connected to the input end of the switching tube Q1, and the negative OUTPUT port OUTPUT-is electrically connected to the OUTPUT end of the switching tube Q1. The resistor R1 can make the output voltage more stable, and when the switching tube Q1 loses the driving voltage, the parasitic capacitance of the control end of the switching tube Q1 will also discharge due to the resistor R1, so that the switching tube Q1 is turned off immediately.

More optionally, the current limiting module 4 further includes resistors R4 and R5, and two ends of the resistor R4 are electrically connected between the control end of the switching tube Q1 and the cathode of the light emitting diode LED 1; the resistor R5 is connected in parallel with the light emitting diode U1A of the optocoupler. The resistors R4 and R5 can play roles of voltage division and current limitation, and protect the light emitting diode LED1 and the light emitting diode U1A of the optocoupler.

Note that the switching transistor may be a triode, a MOS transistor, or other switching transistors, which is not limited. In this embodiment, it is preferable that: the switching tube Q1 is a MOS tube, and a control end, an input end and an output end of the switching tube Q1 are respectively a grid electrode, a drain electrode and a source electrode in sequence; the switching tube Q3 is a MOS tube, and a control end, an input end and an output end of the switching tube Q3 are respectively a grid electrode, a drain electrode and a source electrode in sequence; the switching tube Q2 is a triode, and the control end, the input end and the output end of the switching tube Q2 are respectively provided with a base electrode, a collector electrode and an emitter electrode in sequence; the switching tube Q4 is a triode, and the control end, the input end and the output end of the switching tube Q4 are respectively a base electrode, a collector electrode and an emitter electrode in sequence.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present utility model have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the utility model, the scope of which is defined by the claims and their equivalents.

Claims

1. The output short-circuit protection circuit comprises a transformer T1, a rectifying and filtering module and a load module, wherein the input end of the rectifying and filtering module is electrically connected with a secondary winding of the transformer T1, and the output end of the rectifying and filtering module is electrically connected with the input end of the load module;

the current limiting module comprises a resistor R2 and an optical coupler light emitting diode U1A, the optical coupler isolation module 5 comprises a capacitor C2 and an optical coupler phototriode U1B, one end of the resistor R2, one end of the capacitor C2, the input end of the optical coupler phototriode U1B and the output end of the rectifying and filtering module are electrically connected, the other end of the resistor R2 is electrically connected with an anode of the optical coupler light emitting diode U1A, a cathode of the optical coupler light emitting diode U1A and the other end of the capacitor C2 are both grounded, and the output end of the optical coupler phototriode U1B is electrically connected with a control end of the switching tube Q1;

2. The output short-circuit protection circuit according to claim 1, further comprising a linear voltage stabilizing module, wherein an input end of the linear voltage stabilizing module is electrically connected with an output end of the rectifying and filtering module, and an output end of the linear voltage stabilizing module, one end of the capacitor C2 and an input end of the phototransistor U1B of the optocoupler are electrically connected.

3. The output short-circuit protection circuit according to claim 2, wherein the linear voltage stabilizing module comprises resistors R6, R7, R8, a capacitor C1, a voltage stabilizing diode DZ1 and a switching tube Q2, one end of the resistor R6 is electrically connected with the output end of the rectifying and filtering module, the other end of the resistor R6 is electrically connected with one end of the resistor R7, the other end of the resistor R7, the input end of the switching tube Q2, one end of the capacitor C1 and one end of the resistor R8 are electrically connected, the other end of the resistor R8, the control end of the switching tube Q2 and the negative electrode of the voltage stabilizing diode DZ1 are electrically connected, the output end of the switching tube Q2, one end of the capacitor C2 and the input end of the photo transistor U1B of the photo coupler are electrically connected, and the positive electrode of the voltage stabilizing diode DZ1 and the other end of the capacitor C1 are grounded.

4. The output short-circuit protection circuit according to claim 1, further comprising a short-circuit reminding module, wherein the short-circuit reminding module is connected in series with the switching tube Q1, and the short-circuit reminding module is used for indicating on-off of the switching tube Q1.

5. The output short-circuit protection circuit according to claim 4, wherein the short-circuit reminding module comprises a resistor R3 and a light emitting diode LED1, one end of the resistor R3 is electrically connected with the input end of the switching tube Q1, the other end of the resistor R3 is electrically connected with the anode of the light emitting diode LED1, and the cathode of the light emitting diode LED1 is electrically connected with the output end of the switching tube Q1.

6. The output short-circuit protection circuit according to claim 1, wherein the rectifying and filtering module comprises a polar capacitor CE1, a polar capacitor CE2, a polar capacitor CE3 and a diode D1, wherein the anode of the diode D1 is electrically connected with the secondary winding of the transformer T1, the anode of the diode D1 is used as an input end of the rectifying and filtering module, the cathode of the diode D1, the anode of the polar capacitor CE2 and the anode of the polar capacitor CE3 are electrically connected, and the cathode of the polar capacitor CE1, the cathode of the polar capacitor CE2 and the cathode of the polar capacitor CE3 are all grounded;

7. The output short-circuit protection circuit according to claim 1, wherein the first feedback branch circuit comprises resistors R9, R10, R16, and the resistors R9, R10, R16 are sequentially connected in series between the cathode of the diode D3 and the control end of the switching tube Q3;

8. The output short-circuit protection circuit according to claim 1, wherein the second feedback branch comprises resistors R11, R12, and the resistors R11, R12 are sequentially connected in series between the cathode of the diode D3 and the input terminal of the switching tube Q3.

9. The OUTPUT short-circuit protection circuit according to claim 1, wherein the load module comprises a resistor R1, a positive OUTPUT port output+ and a negative OUTPUT port OUTPUT-, one end of the resistor R1, the positive OUTPUT port output+ and the OUTPUT end of the rectifying and filtering module are electrically connected, the other end of the resistor R1 is electrically connected to the input end of the switching tube Q1, and the negative OUTPUT port OUTPUT is electrically connected to the OUTPUT end of the switching tube Q1.

10. The output short-circuit protection circuit according to claim 5, wherein the current limiting module further comprises resistors R4 and R5, and two ends of the resistor R4 are electrically connected between the control end of the switching tube Q1 and the cathode of the light emitting diode LED 1;