Load short-circuit protection circuit

Abstract

The invention provides a load short-circuit protection circuit which comprises a power supply circuit and a protection circuit. One end of the power supply circuit is connected with a control power supply, and the other end of the power supply circuit is connected with the positive pole of a load for supplying power to the load; and one end of the protection circuit is connected with the power supply circuit, and the other end of the protection circuit is connected with a negative electrode of a load, so that the power supply circuit is disconnected from the load when the load is short-circuited. The short-circuit protection circuit is low in cost and high in timeliness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of short circuit protection, in particular to a load short circuit protection circuit. BACKGROUND

[0002] The intelligent switch generally integrates a short circuit protection function for protecting the intelligent switch from short circuit. The short circuit protection function of the intelligent switch is usually realized by an intelligent switch chip, that is, the intelligent switch chip detects whether there is a short circuit, and if there is a short circuit, the output is closed to realize protection. However, the short circuit protection by the intelligent switch chip is software protection, on the one hand, the chip integrating the short circuit protection function is relatively expensive, and on the other hand, the software detection needs a certain period and cannot timely protect the short circuit. SUMMARY

[0003] The present application provides a load short circuit protection circuit, aiming at solving the problems of high cost and poor timeliness of the current short circuit protection.

[0004] The present application provides a load short circuit protection circuit, which comprises a power supply circuit and a protection circuit; one end of the power supply circuit is connected with a control power supply, the other end of the power supply circuit is connected with a positive electrode of a load for supplying power to the load; one end of the protection circuit is connected with the power supply circuit, the other end of the protection circuit is connected with a negative electrode of the load for disconnecting the connection between the power supply circuit and the load when the load has a short circuit.

[0005] Further, the power supply circuit comprises a direct current power supply, a first switch tube and a second switch tube; the positive electrode of the direct current power supply is connected with the first electrode of the first switch tube, the second electrode of the first switch tube is connected with the positive electrode of the load; the controlled electrode of the second switch tube is connected with the control power supply, the first electrode of the second switch tube is grounded, and the second electrode of the second switch tube is connected with the controlled electrode of the first switch tube.

[0006] Further, the power supply circuit further comprises a first resistor, one end of the first resistor is connected with the positive electrode of the direct current power supply, and the other end of the first resistor is connected with the controlled electrode of the first switch tube.

[0007] Further, the power supply circuit further comprises a voltage stabilizing diode, the negative electrode of the voltage stabilizing diode is connected with the positive electrode of the direct current power supply, and the positive electrode of the voltage stabilizing diode is connected with the controlled electrode of the first switch tube.

[0008] Further, the power supply circuit further comprises a first switch, a second resistor, a third resistor and a fourth resistor; one end of the first switch is connected with the control power supply, the other end of the first switch is connected with one end of the second resistor, the other end of the second resistor is connected with the controlled electrode of the second switch tube and the third resistor respectively, and the other end of the third resistor is grounded; one end of the fourth resistor is connected with the controlled electrode of the first switch tube, and the other end of the fourth resistor is connected with the second electrode of the second switch tube.

[0009] Further, the protection circuit comprises a third switch tube, a fourth switch tube and a fifth switch tube; the controlled electrode of the third switch tube is connected with the negative electrode of the load, the first electrode of the third switch tube is grounded, the second electrode of the third switch tube is connected with the controlled electrode of the fourth switch tube, the first electrode of the fourth switch tube is connected with the controlled electrode of the fifth switch tube, the second electrode of the fourth switch tube is connected with the control power supply, the first electrode of the fifth switch tube is grounded, and the second electrode of the fifth switch tube is connected with the controlled electrode of the second switch tube.

[0010] Further, the protection circuit further comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a first diode; one end of the fifth resistor and one end of the sixth resistor are connected with the negative electrode of the load, the other end of the fifth resistor is grounded, the other end of the sixth resistor is connected with the positive electrode of the first diode, the negative electrode of the first diode is connected with one end of the seventh resistor, the other end of the seventh resistor is connected with one end of the eighth resistor and the controlled electrode of the third switch tube respectively, and the other end of the eighth resistor is grounded.

[0011] Further, the protection circuit further comprises a ninth resistor and a tenth resistor; one end of the ninth resistor is connected with the second electrode of the third switch tube, the other end of the ninth resistor and one end of the tenth resistor are connected with the controlled electrode of the fourth switch tube, and the other end of the tenth resistor is connected with the control power supply.

[0012] Further, a locking circuit is further included, one end of the locking circuit is connected with the second electrode of the fourth switch tube, and the other end of the locking circuit is connected with the controlled electrode of the third switch tube, for maintaining the conduction of the third switch tube.

[0013] Further, the locking circuit comprises an eleventh resistor and a second diode; one end of the eleventh resistor is connected with the second electrode of the fourth switch tube, the other end of the eleventh resistor is connected with the positive electrode of the second diode, and the negative electrode of the second diode is connected with the controlled electrode of the third switch tube.

[0014] The disclosed load short circuit protection circuit comprises a power supply circuit and a protection circuit, the power supply circuit is connected with a control power supply and a positive pole of a load, the protection circuit is connected with the power supply circuit and a negative pole of the load, when the load is short circuited, the protection circuit can disconnect the power supply circuit and the load, thereby realizing short circuit protection without relying on software, reducing cost and improving timeliness. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 is a block schematic diagram of the load short circuit protection circuit provided by an embodiment of the present application;

[0017] Figure 2 is a circuit diagram of the load short circuit protection circuit provided by an embodiment of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0019] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of the described features, integers, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, operations, elements, components, and / or groups thereof.

[0020] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms. It should be further understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations.

[0021] In addition, the directional terms mentioned in the present application, such as "up", "down", "front", "back", "left", "right", "inner", "outer", "side" and the like, are only for reference to the attached drawings and the direction of the product in use. Therefore, the directional terms are used to illustrate and understand the present application, but not to limit the present application. In addition, in the drawings, similar or identical structures are denoted by the same reference numerals.

[0022] Referring to Figures 1 to 2 , Figure 1 is a block schematic diagram of a load short-circuit protection circuit 100 provided by an embodiment of the present application; Figure 2 is a circuit diagram of the load short-circuit protection circuit 100 provided by an embodiment of the present application. As shown in Figures 1 to 2 , the load short-circuit protection circuit 100 comprises a power supply circuit 10 and a protection circuit 20; one end of the power supply circuit 10 is connected with a control power source 200, and the other end of the power supply circuit 10 is connected with a load positive pole, for supplying power to a load 300; one end of the protection circuit 20 is connected with the power supply circuit 10, and the other end of the protection circuit 20 is connected with a load negative pole, for disconnecting the power supply circuit 10 from the load 300 when a short circuit occurs in the load 300.

[0023] Specifically, the load short-circuit protection circuit 100 can comprise the power supply circuit 10 and the protection circuit 20, the power supply circuit 10 is connected with the control power source 200 and the load positive pole of the load 300, and the protection circuit 20 is connected with the power supply circuit 10 and the load negative pole of the load 300.

[0024] The power supply circuit 10 is used for supplying power to the load 300, that is, when the circuit is normal, the power supply circuit 10 provides working power for the load 300, to ensure the normal work of the load 300. The protection circuit 20 is used for interrupting the connection between the power supply circuit 10 and the load 300 when a short circuit fault exists in the load 300, to avoid the power supply circuit 10 still supplying power to the load 300 when a short circuit occurs, and to protect the safety of the load 300.

[0025] As a further embodiment, the power supply circuit 10 comprises a direct current power source DC, a first switch SW tube Q1 and a second switch tube Q2; the positive pole of the direct current power source DC is connected with the first pole of the first switch SW tube Q1, the second pole of the first switch SW tube Q1 is connected with the load positive pole; the controlled pole of the second switch tube Q2 is connected with the control power source 200, the first pole of the second switch tube Q2 is grounded, and the second pole of the second switch tube Q2 is connected with the controlled pole of the first switch SW tube Q1.

[0026] The positive pole of the direct current power supply DC is connected with the first pole of the first switch SW tube Q1, the second pole of the first switch SW tube Q1 is connected with the load 300, the controlled pole of the first switch SW tube Q1 is connected with the second pole of the second switch tube Q2, the controlled pole of the second switch tube Q2 is connected with the control power supply 200, and the first pole of the second switch tube Q2 is grounded.

[0027] The first switch SW tube Q1 can be a PMOS tube, and the second switch tube Q2 can be a triode. The gate of the first switch SW tube Q1 is connected with the collector of the second switch tube Q2, the source of the first switch SW tube Q1 is connected with the positive pole of the direct current power supply DC, the drain of the first switch SW tube Q1 is connected with the load 300, the base of the second switch tube Q2 is connected with the control power supply 200 (VCC), and the emitter of the second switch tube Q2 is grounded. Figure 2

[0028] The first switch SW tube Q1 serves as a main power switch tube and is responsible for providing positive pole power supply for the rear-end load 300. The on and off states of the first switch SW tube Q1 are controlled by the second switch tube Q2, that is, the first switch SW tube Q1 is turned on when the second switch tube Q2 is turned on, and the first switch SW tube Q1 is turned off when the second switch tube Q2 is turned off. The second switch tube Q2 is controlled by the control power supply 200. When the second switch tube Q2 is turned on, the driving signal of the second switch tube Q2 is turned on, and when the second switch tube Q2 is turned off, the driving signal of the second switch tube Q2 is cut off, thereby controlling the on and off of the load 300.

[0029] As a further embodiment, the power supply circuit 10 further comprises a first resistor R1, one end of the first resistor R1 is connected with the positive pole of the direct current power supply DC, and the other end of the first resistor R1 is connected with the controlled pole of the first switch SW tube Q1.

[0030] The one end of the first resistor R1 is connected with the direct current power supply DC, and the other end of the first resistor R1 is connected with the controlled pole of the first switch SW tube Q1. The first resistor R1 serves as a pull-down resistor. When the second switch tube Q2 is not turned on, the gate of the first switch SW tube Q1 is pulled down to the source, thereby avoiding the gate and the source being left hanging and causing the first switch SW tube Q1 to malfunction.

[0031] As a further embodiment, the power supply circuit 10 further comprises a voltage stabilizing diode ZD, the negative pole of the voltage stabilizing diode ZD is connected with the positive pole of the direct current power supply DC, and the positive pole of the voltage stabilizing diode ZD is connected with the controlled pole of the first switch SW tube Q1.

[0032] ​The positive electrode of the voltage stabilizing diode ZD is connected with the controlled electrode of the first switch SW tube Q1, and the negative electrode of the voltage stabilizing diode ZD is connected with the positive electrode of the direct current power supply DC. The voltage stabilizing diode ZD is a voltage stabilizing protection element, and is connected in parallel between the gate and the source of the first switch SW tube Q1, so as to limit the voltage between the gate and the source to not exceed the voltage stabilizing value, and prevent high voltage from breaking through the first switch SW tube Q1.

[0033] As a further embodiment, the power supply circuit 10 further comprises a first switch SW, a second resistance R2, a third resistance R3 and a fourth resistance R4; one end of the first switch SW is connected with the control power supply 200, the other end of the first switch SW is connected with one end of the second resistance R2, the other end of the second resistance R2 is connected with the controlled electrode of the second switch tube Q2 and one end of the third resistance R3 respectively, the other end of the third resistance R3 is grounded; one end of the fourth resistance R4 is connected with the controlled electrode of the first switch SW tube Q1, the other end of the fourth resistance R4 is connected with the second electrode of the second switch tube Q2.

[0034] The one end of the first switch SW is connected with the control power supply 200, the other end of the first switch SW is connected with one end of the second resistance R2, the other end of the second resistance R2 is connected with the controlled electrode of the second switch tube Q2 and one end of the third resistance R3 respectively, the other end of the third resistance R3 is grounded, and the fourth resistance R4 is connected between the second electrode of the second switch tube Q2 and the controlled electrode of the first switch SW tube Q1.

[0035] The first switch SW is a total control switch, which is used for controlling the connection between the control power supply 200 and the base of the second switch tube Q2. When the first switch SW is closed, the control power supply 200 can drive the second switch tube Q2 through the second resistance R2, and when the first switch SW is opened, the driving signal of the second switch tube Q2 is cut off. The second resistance R2 is a current limiting resistance, which limits the current input to the base of the second switch tube Q2 from the control power supply 200, so as to avoid damage of the second switch tube Q2 due to overcurrent. The third resistance R3 is a pull-down resistance, which pulls down the base of the second switch tube Q2 to the negative electrode of the power supply when the first switch SW is not closed, so as to avoid that the base is floating and causes the second switch tube Q2 to be mis-conducted. The fourth resistance R4 is a current limiting resistance, which converts the conduction current of the second switch tube Q2 into the driving voltage of the gate of the first switch SW tube Q1, so as to ensure that the first switch SW tube Q1 is reliably conducted.

[0036] As a further embodiment, the protection circuit 20 comprises a third switch tube Q3, a fourth switch tube Q4 and a fifth switch tube Q5; the control electrode of the third switch tube Q3 is connected with the load negative electrode, the first electrode of the third switch tube Q3 is grounded, the second electrode of the third switch tube Q3 is connected with the control electrode of the fourth switch tube Q4, the first electrode of the fourth switch tube Q4 is connected with the control electrode of the fifth switch tube Q5, the second electrode of the fourth switch tube Q4 is connected with the control power supply 200, the first electrode of the fifth switch tube Q5 is grounded, and the second electrode of the fifth switch tube Q5 is connected with the control electrode of the second switch tube Q2.

[0037] In the protection circuit 20, the third switch tube Q3, the fourth switch tube Q4 and the fifth switch tube Q5 can be triodes, and the base of the third switch tube Q3 is connected with the load negative electrode, the emitter of the third switch tube Q3 is grounded, the collector of the third switch tube Q3 is connected with the base of the fourth switch tube Q4, the emitter of the fourth switch tube Q4 is connected with the control power supply 200, the collector of the fourth switch tube Q4 is connected with the base of the fifth switch tube Q5, the emitter of the fifth switch tube Q5 is grounded, and the collector of the fifth switch tube Q5 is connected with the base of the second switch tube Q2.

[0038] The third switch tube Q3 is a short-circuit trigger switch tube, which is turned on when a short circuit occurs, thereby triggering the subsequent protection circuit 20. The fourth switch tube Q4 is an intermediate driving tube, which is controlled by the third switch tube Q3 and is turned on when the third switch tube Q3 is turned on, thereby driving the fifth switch tube Q5 and the trigger lock circuit 30 and amplifying the short-circuit protection signal. The fifth switch tube Q5 is a pull-down switch tube, which is controlled by the fourth switch tube Q4 and is turned on when the fourth switch tube Q4 is turned on, thereby pulling down the base level of the second switch tube Q2 to the negative electrode of the power supply and forcibly turning off the second switch tube Q2.

[0039] As a further embodiment, the protection circuit 20 further comprises a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a first diode D1; one end of the fifth resistor R5 and one end of the sixth resistor R6 are both connected with the load negative electrode, the other end of the fifth resistor R5 is grounded, the other end of the sixth resistor R6 is connected with the anode of the first diode D1, the cathode of the first diode D1 is connected with one end of the seventh resistor R7, the other end of the seventh resistor R7 is respectively connected with one end of the eighth resistor R8 and the control electrode of the third switch tube Q3, and the other end of the eighth resistor R8 is grounded.

[0040] One end of the fifth resistor R5 and one end of the sixth resistor R6 are connected with the negative pole of the load, the other end of the fifth resistor R5 is grounded, the other end of the sixth resistor R6 is connected with the positive pole of the first diode D1, the negative pole of the first diode D1 is connected with one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected with one end of the eighth resistor R8 and the base of the third switch tube Q3 respectively, the other end of the eighth resistor R8 is grounded.

[0041] The fifth resistor R5 is a current sampling element, the current is small and the voltage across the two terminals is extremely low in normal operation; when the load 300 is short-circuited, the current increases suddenly and the voltage across the two terminals rises rapidly, serving as a short-circuit detection signal source. The sixth resistor R6 is a current-limiting resistor, limiting the current of the voltage signal inputted from the two terminals of the fifth resistor R5 to the base of the third switch tube Q3, protecting the third switch tube Q3 from being damaged by overcurrent. The first diode D1 is a unidirectional conduction element, ensuring that the voltage signal of the fifth resistor R5 can only be inputted to the base of the third switch tube Q3 in a forward direction, preventing reverse current from interfering with the logic. The seventh resistor R7 is a current-limiting resistor, limiting the current inputted to the base of the third switch tube Q3 on the one hand, and transmitting a maintaining current in the locked state on the other hand, ensuring that the third switch tube Q3 is continuously turned on. The eighth resistor R8 is a current-limiting resistor, stabilizing the emitter potential of the third switch tube Q3, preventing abnormal voltage from interfering with the on-off state of the third switch tube Q3.

[0042] As a further embodiment, the protection circuit 20 further comprises a ninth resistor R9 and a tenth resistor R10; one end of the ninth resistor R9 is connected with the second pole of the third switch tube Q3, the other end of the ninth resistor R9 and one end of the tenth resistor R10 are connected with the controlled pole of the fourth switch tube Q4, the other end of the tenth resistor R10 is connected with the control power supply 200.

[0043] One end of the ninth resistor R9 is connected between the collector of the third switch tube Q3 and the base of the fourth switch tube Q4, and one end of the tenth resistor R10 is connected between the emitter and the base of the fourth switch tube Q4.

[0044] The ninth resistor R9 is a current-limiting resistor, limiting the current inputted to the base of the fourth switch tube Q4 when the third switch tube Q3 is turned on, protecting the fourth switch tube Q4. The tenth resistor R10 is a pull-down resistor, used to prevent the fourth switch tube Q4 from being turned on by mistake.

[0045] As a further embodiment, a locking circuit 30 is further included, one end of the locking circuit 30 is connected with the second pole of the fourth switch tube Q4, the other end of the locking circuit 30 is connected with the controlled pole of the third switch tube Q3, used to maintain the conduction of the third switch tube Q3.

[0046] The locking circuit 30 is connected with the second electrode of the fourth switch tube Q4 and the controlled electrode of the third switch tube Q3, and is used for maintaining the protection state after the short circuit is triggered, preventing the circuit from restarting by mistake, that is, maintaining the third switch tube Q3 in the conducting state.

[0047] As a further embodiment, the locking circuit 30 comprises an eleventh resistor R11 and a second diode D2; one end of the eleventh resistor R11 is connected with the second electrode of the fourth switch tube Q4, the other end of the eleventh resistor R11 is connected with the anode of the second diode D2, and the cathode of the second diode D2 is connected with the controlled electrode of the third switch tube Q3.

[0048] The locking circuit 30 can comprise an eleventh resistor R11 and a second diode D2, the eleventh resistor R11 is connected with the collector of the fourth switch tube Q4, the other end of the eleventh resistor R11 is connected with the anode of the second diode D2, and the cathode of the second diode D2 is connected with the base of the third switch tube Q3.

[0049] The eleventh resistor R11 is a current-limiting resistor, which limits the current input from the control power supply 200 to the second diode D2 through the fourth switch tube Q4 in the locking state, avoiding overcurrent damage to the second diode D2 and the fourth switch tube Q4. The second diode D2 is a unidirectional conducting element, which forms a path of “control power supply 200→ fourth switch tube Q4→ eleventh resistor R11→ second diode D2→ seventh resistor R7→ base of third switch tube Q3” in the locking state, ensures the current to flow to the third switch tube Q3 in one direction, and maintains the third switch tube Q3 in the conducting state.

[0050] When the load 300 is short-circuited, the circuit realizes protection through three stages of “short circuit detection→ rapid shutdown→ locking protection”, and the working states of each component are as follows:

[0051] Short circuit detection stage (triggering protection signal)

[0052] When the load 300 is short-circuited, the loop current increases sharply (far more than the normal working current), according to Ohm's law (U=IR), the voltage across the fifth resistor R5 rises rapidly (the voltage is extremely low in normal times, which can be ignored). The rising voltage across the fifth resistor R5 is limited by the sixth resistor R6, and then is limited again by the seventh resistor R7 and the first diode D1 (unidirectional conduction, preventing reverse interference), and is input to the base of the third switch tube Q3. The third switch tube Q3 is turned on after the base obtains sufficient voltage, and a path is formed between the collector and the emitter.

[0053] Rapid shutdown stage (cutting off the power supply of the load 300)

[0054] When the third switch Q3 is turned on, the current flows through the ninth resistor R9 for current limiting and is input to the base of the fourth switch Q4. When the base of the fourth switch Q4 is electrified, the fourth switch Q4 is turned on, and a path is formed between the collector and the emitter. When the fourth switch Q4 is turned on, the control power supply 200 is input to the base of the fifth switch Q5 through the fourth switch Q4 and the twelfth resistor R12, so that the fifth switch Q5 is turned on. When the fifth switch Q5 is turned on, the base of the second switch Q2 is pulled down to the negative pole of the power supply (equivalent to ground). When the base of the second switch Q2 is pulled down to the low level, the second switch Q2 is turned off, and the path between the collector and the emitter is broken. When the second switch Q2 is turned off, the gate of the first switch SW Q1 loses the driving signal, is pulled down to the source through the fourth resistor R4 and the first resistor R1, and the first switch SW Q1 is turned off. At this time, the positive pole of the load is powered off, the negative pole of the load is also cut off through the path of the fifth resistor R5 because the first switch SW Q1 is turned off, and the load 300 is completely powered off. In the process of turning off the first switch SW Q1, the voltage between the two ends of the first switch SW Q1 may fluctuate. The voltage is clamped at 12V or below by the voltage stabilizing diode ZD, so as to prevent the first switch SW Q1 from being broken down by high voltage.

[0055] Locking protection phase (maintain power-off state)

[0056] When the fourth switch Q4 is turned on, the control power supply 200 is input to the base of the fifth switch Q5 through the fourth switch Q4 and the twelfth resistor R12, and is also input to the base of the third switch Q3 through the fourth switch Q4, the eleventh resistor R11, the second diode D2 and the seventh resistor R7, so as to continuously supply power to the base of the third switch Q3. Under the continuous power supply of the above-mentioned circuit, even if the voltage between the two ends of the fifth resistor R5 decreases (no longer provides a trigger signal) after the first switch SW Q1 is turned off, the third switch Q3 still remains in the turned-on state. The third switch Q3 remains in the turned-on state → the fourth switch Q4 remains in the turned-on state → the fifth switch Q5 remains in the turned-on state → the second switch Q2 remains in the turned-off state → the first switch SW Q1 remains in the turned-off state, so that the locking state of maintaining the load 300 powered off after the short circuit is removed is finally realized, and the circuit is prevented from being mistakenly started after the short circuit is recovered.

[0057] The power supply circuit of the load short circuit protection circuit disclosed by the application is connected with the control power supply and the positive pole of the load, and the protection circuit and the power supply circuit are connected with the negative pole of the load. When the load is short circuited, the protection circuit can disconnect the connection between the power supply circuit and the load, so that the short circuit protection is realized without relying on software, the cost is reduced, and the timeliness is improved.

[0058] The above merely describes the 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 various equivalent modifications or replacements within the technical range disclosed by the application, and these modifications or replacements 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 load short-circuit protection circuit, characterized in that, include: A power supply circuit, one end of which is connected to a control power supply and the other end of which is connected to the positive terminal of the load, for supplying power to the load; A protection circuit is provided, one end of which is connected to the power supply circuit and the other end of which is connected to the negative terminal of the load. The protection circuit is used to disconnect the power supply circuit from the load when a short circuit occurs in the load.

2. The load short-circuit protection circuit as described in claim 1, characterized in that, The power supply circuit includes a DC power supply, a first switching transistor, and a second switching transistor. The positive terminal of the DC power supply is connected to the first terminal of the first switching transistor, and the second terminal of the first switching transistor is connected to the positive terminal of the load. The controlled terminal of the second switching transistor is connected to the control power supply, the first terminal of the second switching transistor is grounded, and the second terminal of the second switching transistor is connected to the controlled terminal of the first switching transistor.

3. The load short-circuit protection circuit as described in claim 2, characterized in that, The power supply circuit further includes a first resistor, one end of which is connected to the positive terminal of the DC power supply, and the other end of which is connected to the controlled terminal of the first switching transistor.

4. The load short-circuit protection circuit as described in claim 3, characterized in that, The power supply circuit also includes a Zener diode, the negative terminal of which is connected to the positive terminal of the DC power supply, and the positive terminal of which is connected to the controlled terminal of the first switching transistor.

5. The load short-circuit protection circuit as described in claim 2, characterized in that, The power supply circuit also includes a first switch, a second resistor, a third resistor, and a fourth resistor; One end of the first switch is connected to the control power supply, the other end of the first switch is connected to one end of the second resistor, the other end of the second resistor is connected to the third resistor and the controlled electrode of the second switching transistor, and the other end of the third resistor is grounded. One end of the fourth resistor is connected to the controlled terminal of the first switching transistor, and the other end of the fourth resistor is connected to the second terminal of the second switching transistor.

6. The load short-circuit protection circuit as described in claim 2, characterized in that, The protection circuit includes a third switch, a fourth switch, and a fifth switch; The controlled terminal of the third switch is connected to the negative terminal of the load, the first terminal of the third switch is grounded, the second terminal of the third switch is connected to the controlled terminal of the fourth switch, the first terminal of the fourth switch is connected to the controlled terminal of the fifth switch, the second terminal of the fourth switch is connected to the control power supply, the first terminal of the fifth switch is grounded, and the second terminal of the fifth switch is connected to the controlled terminal of the second switch.

7. The load short-circuit protection circuit as described in claim 6, characterized in that, The protection circuit also includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a first diode; One end of the fifth resistor and one end of the sixth resistor are both connected to the negative terminal of the load. The other end of the fifth resistor is grounded. The other end of the sixth resistor is connected to the positive terminal of the first diode. The negative terminal of the first diode is connected to one end of the seventh resistor. The other end of the seventh resistor is connected to one end of the eighth resistor and the controlled terminal of the third switching transistor. The other end of the eighth resistor is grounded.

8. The load short-circuit protection circuit as described in claim 6, characterized in that, The protection circuit also includes a ninth resistor and a tenth resistor; One end of the ninth resistor is connected to the second terminal of the third switch transistor, the other end of the ninth resistor and one end of the tenth resistor are both connected to the controlled terminal of the fourth switch transistor, and the other end of the tenth resistor is connected to the control power supply.

9. The load short-circuit protection circuit as described in claim 6, characterized in that, It also includes a latching circuit, one end of which is connected to the second terminal of the fourth switching transistor, and the other end of which is connected to the controlled terminal of the third switching transistor, for maintaining the conduction of the third switching transistor.

10. The load short-circuit protection circuit as described in claim 9, characterized in that, The locking circuit includes an eleventh resistor and a second diode; One end of the eleventh resistor is connected to the second terminal of the fourth switching transistor, and the other end of the eleventh resistor is connected to the positive terminal of the second diode. The negative terminal of the second diode is connected to the controlled terminal of the third switching transistor.

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