DC short circuit protection circuit

Abstract

The present invention relates to the technical field of short-circuit protection, and in particular discloses a DC short-circuit protection circuit, which includes a sampling module for sampling a target DC signal output by a DC power supply; a comparison module connected to the sampling module for receiving a reference signal, and also for judging whether the DC power supply is short-circuited according to the comparison between the target DC signal and the reference signal, and outputting a shutdown signal in response to the comparison result of the DC power supply short-circuit; a switch control module connected to the comparison module and also connected between the DC power supply and a load, and the switch control module is used to disconnect the path between the DC power supply and the load according to the shutdown signal. The DC short-circuit protection circuit is based on voltage detection of short circuits, and can quickly shut down the power supply path for any short circuit without increasing the consumption of the main circuit.

Description

Technical Field

[0001] The invention relates to the technical field of short circuit protection, in particular to a direct current short circuit protection circuit. Background Art

[0002] The DC power supply is a common and important type of power supply in a circuit system. In circuit design, if there is no relevant protection device between the DC power supply and the load, when a short circuit occurs in the DC power supply, the circuit may be damaged, and in severe cases, the DC power supply may even be damaged. It can be seen that the short-circuit protection circuit is the key to protecting the DC power supply, and its performance directly affects the safe operation of the DC power supply. However, the solution of using a series sampling resistor to achieve short-circuit protection in the prior art has the problem of large circuit loss. Summary of the invention

[0003] Based on this, it is necessary to provide a DC short-circuit protection circuit to address the problems existing in the existing short-circuit protection circuit.

[0004] A DC short-circuit protection circuit comprises a sampling module for sampling a target DC signal output by a DC power supply; a comparison module connected to the sampling module and used to receive a reference signal and further used to judge whether the DC power supply is short-circuited according to a comparison between the target DC signal and the reference signal, and output a shutdown signal in response to a comparison result that the DC power supply is short-circuited; a switch control module connected to the comparison module and also connected between the DC power supply and a load, and the switch control module is used to disconnect the path between the DC power supply and the load according to the shutdown signal.

[0005] In one embodiment, the comparison module is further used to output an alarm signal in response to the comparison result of the DC power supply short circuit, and the DC short circuit protection circuit also includes: an alarm module, connected to the comparison module, and used to generate alarm information according to the alarm signal.

[0006] In one embodiment, the comparison module includes a switch unit connected between a reference power supply and the comparison module, and used to control the on and off of the connection between the reference power supply and the comparison module; a delay comparison unit is respectively connected to the switch unit and the sampling module, and after the switch unit controls the connection between the reference power supply and the comparison module, the reference signal is received with a delay of a preset time, and whether the DC power supply is short-circuited is determined based on the comparison between the target DC signal and the reference signal, and a shutdown signal is output in response to the comparison result that the DC power supply is short-circuited.

[0007] In one of the embodiments, the comparison module is further configured to reset the shutdown signal in response to a reset instruction.

[0008] In one embodiment, the delay comparison unit includes a first resistor, a second resistor, a first capacitor, a first transistor and a second transistor, the first end of the first resistor is connected to the switch unit, the second end of the first resistor is connected to the gate of the first transistor, the first capacitor is connected between the gate of the first transistor and the source of the first transistor, the first end of the second resistor is connected to the drain of the first transistor, the second end of the second resistor is connected to an auxiliary power supply, the gate of the second transistor is connected to the second end of the second resistor, the drain of the second transistor is connected to the sampling module and the switch control module, and the source of the first transistor and the source of the second transistor are both grounded.

[0009] In one embodiment, the DC power supply is a positive power supply, the sampling module includes a third resistor, a fourth resistor, a third transistor and a first voltage regulator diode, the first end of the third resistor is connected to the auxiliary power supply, the second end of the third resistor is respectively connected to the switch control module, the delay comparison unit and the drain of the third transistor, the gate of the third transistor is respectively connected to the first end of the fourth resistor and the first pole of the first voltage regulator diode, the source of the third transistor is respectively connected to the second pole of the first voltage regulator diode and the ground, and the second end of the fourth resistor is connected to the load.

[0010] In one embodiment, the DC power supply is a negative power supply, and the sampling module includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a third transistor, a fourth transistor, a fifth transistor, a first voltage regulator diode and a second voltage regulator diode. The first end of the third resistor is connected to the auxiliary power supply, the second end of the third resistor is respectively connected to the switch control module, the delay comparison unit and the drain of the third transistor, the gate of the third transistor is respectively connected to the first end of the fourth resistor and the drain of the fourth transistor, the source of the third transistor is respectively connected to the second end of the fourth resistor and the ground, the gate of the fourth transistor is respectively connected to the second pole of the first voltage regulator diode, the first end of the fifth resistor and the first end of the sixth resistor, the source of the fourth transistor is respectively connected to the first pole of the first voltage regulator diode, the second end of the sixth resistor and the auxiliary power supply, the second end of the fifth resistor is connected to the drain of the fifth transistor, the gate of the fifth transistor is respectively connected to the first end of the seventh resistor and the first pole of the second voltage regulator diode, and the source of the fifth transistor is respectively connected to the second pole of the second voltage regulator diode and the load.

[0011] In one embodiment, the DC power supply is a positive power supply, and the switch control module includes an eighth resistor, a ninth resistor, a tenth resistor, a sixth transistor, a seventh transistor, an eighth transistor and a third voltage-stabilizing diode. The first end of the eighth resistor is connected to the switch unit, the second end of the eighth resistor is respectively connected to the drain of the sixth transistor and the gate of the seventh transistor, the gate of the sixth transistor is respectively connected to the delay comparison unit and the sampling module, the source of the sixth transistor and the source of the seventh transistor are both grounded, the drain of the seventh transistor is connected to the first end of the ninth resistor, the second end of the ninth resistor is respectively connected to the first end of the tenth resistor, the second electrode of the third voltage-stabilizing diode and the gate of the eighth transistor, the second end of the tenth resistor and the first electrode of the third voltage-stabilizing diode are both connected to the source of the eighth transistor, the source of the eighth transistor is also connected to the DC power supply, and the drain of the eighth transistor is connected to the load.

[0012] In one embodiment, the DC power supply is a negative power supply, and the switch control module includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a sixth transistor, a seventh transistor, an eighth transistor, a ninth transistor and a third voltage stabilizing diode. The first end of the eighth resistor is connected to the switch unit, the second end of the eighth resistor is respectively connected to the drain of the sixth transistor and the gate of the seventh transistor, the gate of the sixth transistor is respectively connected to the delay comparison unit and the sampling module, the source of the sixth transistor and the source of the seventh transistor are both grounded, the drain of the seventh transistor is respectively connected to the first end of the eleventh resistor and the gate of the ninth transistor, the second end of the eleventh resistor and the source of the ninth transistor are both connected to the auxiliary power supply, the drain of the ninth transistor is connected to the first end of the ninth resistor, the second end of the ninth resistor is respectively connected to the first end of the tenth resistor, the first electrode of the third voltage stabilizing diode and the gate of the eighth transistor, the second end of the tenth resistor and the second electrode of the third voltage stabilizing diode are both connected to the source of the eighth transistor, the source of the eighth transistor is also connected to the DC power supply, and the drain of the eighth transistor is connected to the load.

[0013] In one embodiment, when the DC power supply is a positive power supply, the first transistor, the second transistor, the third transistor, the sixth transistor and the seventh transistor are all N-type transistors, and the eighth transistor is a P-type transistor; when the DC power supply is a negative power supply, the first transistor, the second transistor, the third transistor, the fifth transistor, the sixth transistor, the seventh transistor and the eighth transistor are all N-type transistors, and the fourth transistor and the ninth transistor are all P-type transistors.

[0014] The DC short-circuit protection circuit uses a sampling module to sample the target DC signal output by the DC power supply, and uses a comparison module to receive a reference signal and compare the target DC signal with the reference signal. It is determined whether the DC power supply is short-circuited based on the comparison result. When the DC power supply is short-circuited, the comparison module outputs a shutdown signal. The switch control module disconnects the path between the DC power supply and the load according to the shutdown signal. The DC short-circuit protection circuit detects short circuits based on voltage. For any short circuit, it can quickly shut down the power supply path without increasing the consumption of the main circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the implementation methods of this specification or the technical solutions in the prior art, the drawings required for use in the implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 This is a schematic diagram of the structure of a DC short-circuit protection circuit in one of the embodiments of the present application;

[0017] Figure 2 This is a schematic structural diagram of a DC short-circuit protection circuit in another embodiment of the present application;

[0018] Figure 3 This is a structural schematic diagram of a DC short-circuit protection circuit in another embodiment of the present application;

[0019] Figure 4 This is a circuit diagram of a DC short-circuit protection circuit for a positive power supply in one embodiment of the present application;

[0020] Figure 5 FIG. 1 is a circuit diagram of a DC short-circuit protection circuit for a negative power supply in one embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to understand the disclosure of the present invention more thoroughly and comprehensively.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0023] Figure 1 This is a structural diagram of a DC short circuit protection circuit in one of the embodiments of the present application. In one of the embodiments, the DC short circuit protection circuit may include a sampling module 100, a comparison module 200 and a switch control module 300.

[0024] The sampling module 100 can be used to sample the target DC signal output by the DC power supply. In this embodiment, the DC power supply can refer to a positive power supply or a negative power supply. Further, the target DC signal output by the DC power supply can be a positive voltage signal or a negative voltage signal.

[0025] The comparison module 200 can be connected to a reference power supply to receive a reference signal. In a specific application, the type of the reference power supply can be adjusted according to the type of the DC power supply. For example, when the DC power supply is a positive power supply, the reference power supply can also be a positive power supply. The comparison module 200 can also be connected to the sampling module 100 to compare the target DC signal and the reference signal, and determine whether the DC power supply is short-circuited according to the comparison between the target DC signal and the reference signal. In a specific application, the determination condition of the DC power supply short circuit can be adaptively designed according to different applications. For example, when the level value of the target DC signal is less than the level value of the reference signal, the comparison module 200 determines that the DC power supply is short-circuited; when the level value of the target DC signal is not equal to the level value of the reference signal, the comparison module 200 determines that the DC power supply is short-circuited. When the comparison module 200 determines that the DC power supply is short-circuited according to the comparison between the target DC signal and the reference signal, the comparison module 200 can output a shutdown signal.

[0026] The switch control module 300 may be connected to the comparison module 200 to receive the shutdown signal output by the comparison module 200. The switch control module 300 may also be connected between the DC power supply and the load to control the on / off connection between the DC power supply and the load. After receiving the shutdown signal, the switch control module 300 may disconnect the connection path between the DC power supply and the load according to the shutdown signal.

[0027] The DC short-circuit protection circuit uses the sampling module 100 to sample the target DC signal output by the DC power supply, and uses the comparison module 200 to compare the target DC signal with the reference signal to achieve real-time monitoring of the DC power supply. When the DC power supply is short-circuited, the comparison module 200 can determine that the DC power supply is short-circuited according to the abnormality of the target DC signal and output a shutdown signal to the switch control module 300, so that the switch control module 300 can quickly shut down the path between the DC power supply and the load according to the shutdown signal to achieve short-circuit protection of the DC power supply. At the same time, the DC short-circuit protection circuit is a short-circuit detection based on voltage value comparison for the DC power supply. For any short-circuit situation, it can be quickly shut down without increasing the main circuit consumption, so as to improve the safety factor of the circuit system.

[0028] Figure 2 This is a schematic structural diagram of a DC short circuit protection circuit in another embodiment of the present application. In one of the embodiments, the DC short circuit protection circuit may further include an alarm module 400 .

[0029] The comparison module 200 can also output an alarm signal when judging that the DC power supply is short-circuited according to the comparison of the target DC signal and the reference signal. The alarm module 400 can be connected to the comparison module 200 to receive the alarm signal output by the comparison module 200, and the alarm module 400 can also generate an alarm message according to the alarm signal. In practical applications, short-circuit alarms can be implemented in different forms according to different application requirements. For example, the alarm message can refer to sound and light information, and the alarm module 400 sends sound / light according to the alarm signal to transmit the alarm message; the alarm message can also be text information, and the alarm module 400 generates text content according to the alarm signal to prompt the alarm message.

[0030] The above-mentioned DC short-circuit protection circuit can not only quickly cut off the path between the power supply and the load when the DC power supply is short-circuited, but also send out an alarm signal to remind the user, alerting the user to safety problems in the circuit, thereby further improving the safety of the circuit system.

[0031] Figure 3 This is a schematic structural diagram of a DC short circuit protection circuit in another embodiment of the present application. In one embodiment, the comparison module 200 may include a switch unit 210 and a delay comparison unit 220 .

[0032] The switch unit 210 can be connected between the reference power supply and the comparison module 200, and the switch unit 210 can be used to control the on and off of the connection between the reference power supply and the comparison module 200. In practical applications, the switch unit 210 can use different devices to implement the switch function according to different requirements. For example, the switch unit 210 can be designed as a transistor, or as a toggle switch, a key switch, etc.

[0033] The delay comparison unit 220 can be connected to the switch unit 210 and the sampling module 100 respectively. After the switch unit 210 controls the connection between the reference power supply and the comparison module 200, the delay comparison unit 220 can delay the preset time to receive the reference signal. The delay comparison unit 220 can also determine whether the DC power supply is short-circuited based on the comparison between the target DC signal and the reference signal, and output a shutdown signal in response to the comparison result of the DC power supply short-circuit.

[0034] The DC short-circuit protection circuit can control the opening and closing of the short-circuit protection function by using the switch unit 210. When the DC power supply needs to be monitored for short circuit in real time, the switch unit 210 can be made to conduct the connection between the reference power supply and the comparison module 200; when the DC power supply does not need to be monitored for short circuit, the switch unit 210 can be made to disconnect the connection between the reference power supply and the comparison module 200. In addition, on the one hand, the delay comparison unit 220 can be used to delay the input of the reference signal to prevent the DC short-circuit protection circuit from being falsely triggered due to overly sensitive reaction, thereby affecting the normal operation of the DC power supply; on the other hand, the switch unit 210 and the delay comparison unit 220 can cooperate to achieve self-locking after a short circuit. After the short circuit problem of the DC power supply is solved, the switch unit 210 is used to restart the DC short-circuit protection circuit to restore the path between the DC power supply and the load and eliminate the alarm signal, further improving the safety factor of the circuit system.

[0035] Figure 4 This is a circuit diagram of a DC short-circuit protection circuit for a positive power supply in one embodiment of the present application. In one embodiment, the delay comparison unit 220 may include a first resistor R1, a second resistor R2, a first capacitor C1, a first transistor Q1 and a second transistor Q2.

[0036] The first end of the first resistor R1 can be connected to the switch unit 210, and the second end of the first resistor R1 can be connected to the gate of the first transistor Q1. In this embodiment, the first resistor R1 can be used as a current limiting resistor of the first transistor Q1, and the first resistor R1 is used to limit the driving current of the first transistor Q1 to achieve current limiting protection for the first transistor Q1. The first capacitor C1 can be connected between the gate of the first transistor Q1 and the source of the first transistor Q1, and the first capacitor C1 can be used to implement the delay function of the delay comparison unit 220. The delay time t can be the time from the switch unit 210 turning on to the first transistor Q1 turning on.

[0037] Specifically, after the switch unit 210 is turned on, the comparison module 200 is connected to the reference power supply, and the reference signal EN output by the reference power supply is input into the comparison module 200 through the switch unit 210. The reference signal EN charges the first capacitor C1. After the first capacitor C1 is charged for t seconds (i.e., the delay time t), the potential of the plate connected to the gate of the first transistor Q1 of the first capacitor C1 rises to the turn-on threshold voltage of the first transistor Q1, and the first transistor Q1 is turned on. Thus, the first capacitor C1 realizes the delay of the reference signal EN input. Among them, the calculation formula of the delay time t can be: t=R*C*ln(E / (EV t )). In the formula, R can be the resistance value of the first resistor R1, C can be the capacitance value of the first capacitor C1, E can be the voltage value of the reference signal EN, V t It can be the turn-on threshold voltage of the first transistor Q1.

[0038] The first end of the second resistor R2 can be connected to the drain of the first transistor Q1, and the second end of the second resistor R2 can be connected to the auxiliary power supply. The auxiliary power supply can continuously provide a high level relative to the reference ground GND. Preferably, the high level can be a level signal of about +5V.

[0039] The gate of the second transistor Q2 can be connected to the second end of the second resistor R2, and the second resistor R2 can be used as a current limiting resistor of the second transistor Q2. The second resistor R2 is used to limit the driving current of the second transistor Q2 to achieve current limiting protection for the second transistor Q2. The drain of the second transistor Q2 can be connected to the sampling module 100 and the switch control module 300 respectively, and the source of the first transistor Q1 and the source of the second transistor Q2 are both grounded.

[0040] In one embodiment, see Figure 4 When the DC power supply is a positive power supply, the target DC signal +VOUT output by the DC power supply is a positive DC voltage. The sampling module 100 may include a third resistor R3, a fourth resistor R4, a third transistor Q3 and a first voltage regulator diode D1.

[0041] The first end of the third resistor R3 can be connected to the auxiliary power supply, and the second end of the third resistor R3 can be connected to the switch control module 300, the delay comparison unit 220 and the drain of the third transistor Q3 respectively. Among them, the second end of the third resistor R3 can be connected to the drain of the second transistor Q2 in the delay comparison unit 220. The gate of the third transistor Q3 can be connected to the first end of the fourth resistor R4 and the first electrode of the first voltage zener diode D1 respectively. The source of the third transistor Q3 can be connected to the second electrode of the first voltage zener diode D1 and the ground respectively, and the second end of the fourth resistor R4 can be connected to the load.

[0042] In this embodiment, the first electrode of the first voltage zener diode D1 may be the cathode of the first voltage zener diode D1, and the second electrode of the first voltage zener diode D1 may be the anode of the first voltage zener diode D1. The first voltage zener diode D1 is connected between the gate and the source of the third transistor Q3, and can be used to achieve voltage stabilization of the third transistor Q3, protecting the third transistor Q3 from being damaged by high voltage. Preferably, a voltage zener diode with a voltage stabilization value of about 5V can be selected as the first voltage zener diode D1.

[0043] In one embodiment, see Figure 4 When the DC power supply is a positive power supply, the target DC signal +VOUT output by the DC power supply is a positive DC voltage. The switch control module 300 may include an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8 and a third voltage stabilizing diode D3.

[0044] The first end of the eighth resistor R8 can be connected to the switch unit 210, that is, the first end of the eighth resistor R8 can also be connected to the first end of the first resistor R1. The second end of the eighth resistor R8 can be connected to the drain of the sixth transistor Q6 and the gate of the seventh transistor Q7 respectively. The eighth resistor R8 can be used as a current limiting resistor of the seventh transistor Q7, and the eighth resistor R8 is used to limit the driving current of the seventh transistor Q7 to achieve current limiting protection for the seventh transistor Q7. The gate of the sixth transistor Q6 can be connected to the delay comparison unit 220 and the sampling module 100 respectively, and the source of the sixth transistor Q6 and the source of the seventh transistor Q7 are both grounded. Among them, the gate of the sixth transistor Q6 can be connected to the drain of the second transistor Q2 in the delay comparison unit 220 and the second end of the third resistor R3 in the sampling module 100. The third resistor R3 can be used as a current limiting resistor of the sixth transistor Q6, and the third resistor R3 is used to limit the driving current of the sixth transistor Q6 to achieve current limiting protection for the sixth transistor Q6.

[0045] The drain of the seventh transistor Q7 can be connected to the first end of the ninth resistor R9, and the second end of the ninth resistor R9 can be connected to the first end of the tenth resistor R10, the second pole of the third voltage stabilizing diode D3 and the gate of the eighth transistor Q8 respectively. The ninth resistor R9 can be used as a current limiting resistor of the eighth transistor Q8, and the ninth resistor R9 is used to limit the driving current of the eighth transistor Q8 to achieve current limiting protection for the eighth transistor Q8. The second end of the tenth resistor R10 and the first pole of the third voltage stabilizing diode D3 can both be connected to the source of the eighth transistor Q8. The source of the eighth transistor Q8 can also be connected to a DC power supply, and the drain of the eighth transistor Q8 can be connected to a load. In this embodiment, the first pole of the third voltage stabilizing diode D3 can be the cathode of the third voltage stabilizing diode D3, and the second pole of the third voltage stabilizing diode D3 can be the anode of the third voltage stabilizing diode D3.

[0046] The eighth transistor Q8 can be connected between the DC power supply and the load, and the on-off control of the connection between the DC power supply and the load can be achieved by changing the on-off of the eighth transistor Q8. The third voltage stabilizing diode D3 is connected between the gate and the source of the eighth transistor Q8, and can be used to achieve voltage stabilization of the eighth transistor Q8 and protect the eighth transistor Q8 from being damaged by high voltage. Preferably, a voltage stabilizing diode with a voltage stabilization value of about 5V can be selected as the third voltage stabilizing diode D3. The tenth resistor R10 is connected in parallel at both ends of the third voltage stabilizing diode D3, so that the current in the circuit can be smoothly controlled, thereby further achieving voltage stability.

[0047] In one embodiment, see Figure 4 , when the DC power supply is a positive power supply, the target DC signal +VOUT output by the DC power supply is a positive DC voltage. The first transistor Q1, the second transistor Q2, the third transistor Q3, the sixth transistor Q6 and the seventh transistor Q7 can all be N-type transistors, and the eighth transistor Q8 can be a P-type transistor. That is, the first transistor Q1, the second transistor Q2, the third transistor Q3, the sixth transistor Q6 and the seventh transistor Q7 are turned on according to a high level and turned off according to a low level, and the eighth transistor Q8 is turned on according to a low level and turned off according to a high level, so that the DC short-circuit protection circuit can use the conduction characteristics of each transistor in the circuit to achieve short-circuit protection of the DC positive power supply.

[0048] In addition, in practical applications, the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 can be adaptively designed according to different application requirements. Similarly, the capacitance value of the first capacitor C1 can also be adaptively designed according to requirements.

[0049] In this embodiment, Figure 4Taking the DC short-circuit protection circuit shown as an example, its working process is explained. The description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. Figure 4 In the figure, +5V is the high level provided by the auxiliary power supply, GND is the reference 0V of the circuit, V+_EN is the reference signal, the potential at point A is high when the switch unit 210 is turned on, and the potential at point A is low when the switch unit 210 is turned off. +VIN can be the DC input terminal of the DC short-circuit protection circuit, +VIN can be connected to a DC power supply, +VOUT can be the DC output terminal of the DC short-circuit protection circuit, and +VOUT can be connected to a load. Among them, the DC power supply can be a DC positive power supply. The low level is a level signal close to 0V, and the voltage regulation value of the first Zener diode D1 and the second Zener diode D2 is about 5V. V+_Alarm can be connected to the alarm module 400, and when V+_Alarm is high, it is regarded as an output alarm signal, and when V+_Alarm is low, there is no alarm signal.

[0050] Embodiment 1: When the switch unit 210 is turned off, the potential at point A is low, and the gate of the seventh transistor Q7 is low, so the seventh transistor Q7 is turned off. The gate of the eighth transistor Q8 is high, so the eighth transistor Q8 is turned off, and the connection between the DC input terminal of the DC short-circuit protection circuit and the DC output terminal of the DC short-circuit protection circuit is disconnected. At the same time, since the potential at point A is low, the gate of the first transistor Q1 is also low, so the first transistor Q1 is turned off, and the +5V high level provided by the auxiliary power supply is transmitted to the gate of the second transistor Q2 through the second resistor R2, so that the gate of the second transistor Q2 is high, and the second transistor Q2 is turned on. After the second transistor Q2 is turned on, it is grounded, pulling down the potential at V+_Alarm. Therefore, the DC short-circuit protection circuit does not output an alarm signal at this time.

[0051] Embodiment 2: The switch unit 210 is turned on when the DC power supply has no short-circuit problem. After the switch unit 210 is turned on, the potential at point A is high, and the gate of the seventh transistor Q7 is high, and the seventh transistor Q7 is turned on. After the seventh transistor Q7 is turned on, the potential at the gate of the eighth transistor Q8 is pulled down, so that the eighth transistor Q8 is turned on, and the connection between the DC power supply and the load is turned on. At the same time, since the potential at point A is high, after t seconds after the switch unit 210 is turned on and the first capacitor C1 is charged for t seconds, the potential at the gate of the first transistor Q1 is also high, so the first transistor Q1 is turned on. After the first transistor Q1 is turned on, it is grounded, pulling down the potential at the gate of the second transistor Q2, and the second transistor Q2 is turned off.

[0052] At the same time, since the eighth transistor Q8 is turned on, the DC input terminal of the DC short circuit protection circuit and the DC output terminal of the DC short circuit protection circuit are turned on, so the potential of the gate of the third transistor Q3 is also high, and the third transistor Q3 is turned on. After the third transistor Q3 is turned on, it is grounded, pulling down the potential at V+_Alarm. Therefore, the DC short circuit protection circuit does not output an alarm signal at this time.

[0053] Embodiment 3: The switch unit 210 is turned on when the DC power supply has no short-circuit problem, and after the switch unit 210 has been turned on for a period of time, the DC power supply suddenly short-circuits. The startup process of the switch unit 210 when the DC power supply has no short-circuit problem is the same as that of Embodiment 1, and is not described in detail here. When the power supply is turned on normally and works for a period of time, +VOUT is short-circuited to GND, that is, +VOUT is at a low level. At this time, the potential of the gate of the third transistor Q3 becomes a low level, and the third transistor Q3 is turned off, so that V+_Alarm becomes a high level, and the DC short-circuit protection circuit outputs an alarm signal.

[0054] At the same time, since V+_Alarm is at a high level, the potential at the gate of the sixth transistor Q6 is also at a high level, and the sixth transistor Q6 is turned on. After the sixth transistor Q6 is turned on, it is grounded, pulling down the potential at the gate of the seventh transistor Q7, and the seventh transistor Q7 is turned off. After the seventh transistor Q7 is turned off, the gate of the eighth transistor Q8 is at a high level, so the eighth transistor Q8 is turned off. After the eighth transistor Q8 is turned off, the connection between the DC input terminal of the DC short-circuit protection circuit and the DC output terminal of the DC short-circuit protection circuit is disconnected. Since the turn-on and turn-off time of the transistor is very short, at the nanosecond level, the above-mentioned DC short-circuit protection circuit can quickly shut down the path for a sudden short circuit of the DC power supply and send an alarm signal.

[0055] Embodiment 4: The switch unit 210 is turned on when the DC power supply has a short circuit problem. After the switch unit 210 is turned on, the potential at point A is high, and the gate of the seventh transistor Q7 is high, and the seventh transistor Q7 is turned on. After the seventh transistor Q7 is turned on, the potential of the gate of the eighth transistor Q8 is pulled down, so that the eighth transistor Q8 is turned on, and the connection between the DC power supply and the load is turned on.

[0056] Since the potential at point A is high, after the switch unit 210 is turned on for t seconds and the first capacitor C1 is charged for t seconds, the potential at the gate of the first transistor Q1 is also high, so the first transistor Q1 is turned on. After the first transistor Q1 is turned on, it is grounded, lowering the potential at the gate of the second transistor Q2, and the second transistor Q2 is turned off.

[0057] At the same time, since the eighth transistor Q8 is turned on, the DC input terminal of the DC short circuit protection circuit and the DC output terminal of the DC short circuit protection circuit are turned on. At this time, since the DC power supply is short-circuited, +VOUT is at a low level, so the potential of the gate of the third transistor Q3 is also at a low level, and the third transistor Q3 is turned off. At this time, the potential of V+_Alarm is at a high level, that is, the DC short circuit protection circuit outputs an alarm signal.

[0058] Since V+_Alarm is at a high level, the potential at the gate of the sixth transistor Q6 is also at a high level, and the sixth transistor Q6 is turned on. After the sixth transistor Q6 is turned on, it is grounded, pulling down the potential at the gate of the seventh transistor Q7, and the seventh transistor Q7 is turned off. After the seventh transistor Q7 is turned off, the gate of the eighth transistor Q8 is at a high level, so the eighth transistor Q8 is turned off. After the eighth transistor Q8 is turned off, the connection between the DC input terminal of the DC short-circuit protection circuit and the DC output terminal of the DC short-circuit protection circuit is disconnected.

[0059] It can be seen that the above-mentioned DC short-circuit protection circuit realizes short-circuit detection for the DC power supply based on voltage. At the same time, the transistor used in the DC short-circuit protection circuit has the characteristic of low internal resistance, which can make the circuit have relatively small loss and does not increase the consumption of the main circuit. At the same time, since the above-mentioned DC short-circuit protection circuit can be built using discrete components, fewer components are used, and commonly used components such as transistors, voltage regulators, resistors, capacitors, etc. are used, it also has the advantage of low circuit cost.

[0060] In one embodiment, the comparison module 200 can also be used to respond to the reset instruction to reset the shutdown signal. In this embodiment, the comparison module 200 can close the switch unit 210 based on the reset instruction, so that the delay comparison unit 220 resets the shutdown signal. Specifically, after a short circuit problem occurs in the DC power supply, and the DC short circuit protection circuit quickly shuts off the path and sends an alarm signal. Even after the short circuit problem of the DC power supply is solved, since the first capacitor C1 completes the charging at the beginning of the circuit opening, the potential of the gate of the first transistor Q1 can be maintained, so that the first transistor Q1 is turned on, the first transistor Q1 is grounded after turning on, and the potential at the gate of the second transistor Q2 is pulled down, and the second transistor Q2 is turned off. At the same time, the third transistor Q3 is also in the off state. It can be seen that even after the short circuit problem is removed, the DC short circuit protection circuit still remains in the short circuit protection state, and V+_Alarm continues to be a high level, that is, the DC short circuit protection circuit continues to output an alarm signal.

[0061] According to the above embodiments, when a short circuit occurs in the DC power supply, the DC short circuit protection circuit can quickly shut down the path and send out an alarm signal. After the short circuit problem of the DC power supply is solved, the user needs to give a reset instruction, and the comparison module 200 can reset the shutdown signal based on the reset instruction to prevent the DC short circuit protection circuit from restoring the path due to short-term voltage fluctuations, resulting in potential safety hazards. It can be seen that the DC short circuit protection circuit uses the switch unit 210 and the delay comparison unit 220 to cooperate, not only to quickly shut down the power path for the short circuit problem, but also to self-lock after detecting the short circuit problem, and maintain in the short circuit protection state. The user needs to restore to the normal state through the reset instruction, thereby further improving the safety factor of the circuit.

[0062] Figure 5 This is a circuit diagram of a DC short circuit protection circuit for a negative power supply in one embodiment of the present application. In one embodiment, when the DC power supply is a negative power supply, the target DC signal -VOUT output by the DC power supply is a negative DC voltage. The sampling module 100 may include a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5, a first Zener diode D1, and a second Zener diode D2.

[0063] The first end of the third resistor R3 can be connected to the auxiliary power supply, and the second end of the third resistor R3 can be connected to the switch control module 300, the delay comparison unit 220 and the drain of the third transistor Q3. Among them, the second end of the third resistor R3 can be connected to the drain of the second transistor Q2 in the delay comparison unit 220. The gate of the third transistor Q3 is respectively connected to the first end of the fourth resistor R4 and the drain of the fourth transistor Q4, and the source of the third transistor Q3 is respectively connected to the second end of the fourth resistor R4 and the ground. The gate of the fourth transistor Q4 is respectively connected to the second pole of the first voltage zener diode D1, the first end of the fifth resistor R5 and the first end of the sixth resistor R6, and the source of the fourth transistor Q4 is respectively connected to the first pole of the first voltage zener diode D1, the second end of the sixth resistor R6 and the auxiliary power supply.

[0064] In this embodiment, the first electrode of the first voltage zener diode D1 can be the cathode of the first voltage zener diode D1, and the second electrode of the first voltage zener diode D1 can be the anode of the first voltage zener diode D1. The first voltage zener diode D1 is connected between the gate and the source of the fourth transistor Q4, and can be used to achieve voltage stabilization of the fourth transistor Q4, protecting the fourth transistor Q4 from being damaged by high voltage. The sixth resistor R6 can be used as a current limiting resistor of the fourth transistor Q4, and the eighth resistor R8 is used to limit the driving current of the fourth transistor Q4 to achieve current limiting protection for the fourth transistor Q4.

[0065] The second end of the fifth resistor R5 is connected to the drain of the fifth transistor Q5, the gate of the fifth transistor Q5 is respectively connected to the first end of the seventh resistor R7 and the first electrode of the second zener diode D2, and the source of the fifth transistor Q5 is respectively connected to the second electrode of the second zener diode D2 and the load.

[0066] In this embodiment, the first electrode of the second voltage stabilizing diode D2 may be the cathode of the second voltage stabilizing diode D2, and the second electrode of the second voltage stabilizing diode D2 may be the anode of the second voltage stabilizing diode D2. The second voltage stabilizing diode D2 is connected between the gate and the source of the fifth transistor Q5, and can be used to achieve voltage stabilization of the second voltage stabilizing diode D2, protecting the fifth transistor Q5 from being damaged by high voltage. Preferably, a voltage stabilizing diode with a voltage stabilization value of about 5V can be selected as the first voltage stabilizing diode D1 and / or the second voltage stabilizing diode D2.

[0067] In one embodiment, see Figure 5 When the DC power supply is a negative power supply, the target DC signal -VOUT output by the DC power supply is a negative DC voltage. The switch control module 300 may include an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9 and a third voltage stabilizing diode D3.

[0068] The first end of the eighth resistor R8 can be connected to the switch unit 210, that is, the first end of the eighth resistor R8 can also be connected to the first end of the first resistor R1. The second end of the eighth resistor R8 can be connected to the drain of the sixth transistor Q6 and the gate of the seventh transistor Q7 respectively. The eighth resistor R8 can be used as a current limiting resistor of the seventh transistor Q7, and the eighth resistor R8 is used to limit the driving current of the seventh transistor Q7 to achieve current limiting protection for the seventh transistor Q7. The gate of the sixth transistor Q6 is connected to the delay comparison unit 220 and the sampling module 100 respectively, and the source of the sixth transistor Q6 and the source of the seventh transistor Q7 are both grounded. Among them, the gate of the sixth transistor Q6 can be connected to the drain of the second transistor Q2 in the delay comparison unit 220 and the second end of the third resistor R3 in the sampling module 100. The third resistor R3 can be used as a current limiting resistor of the sixth transistor Q6, and the third resistor R3 is used to limit the driving current of the sixth transistor Q6 to achieve current limiting protection for the sixth transistor Q6.

[0069] The drain of the seventh transistor Q7 can be connected to the first end of the eleventh resistor R11 and the gate of the ninth transistor Q9 respectively, and the second end of the eleventh resistor R11 and the source of the ninth transistor Q9 are both connected to the auxiliary power supply. The eleventh resistor R11 can be used as a current limiting resistor of the seventh transistor Q7, and the eleventh resistor R11 is used to limit the driving current of the seventh transistor Q7 to achieve current limiting protection for the seventh transistor Q7. The drain of the ninth transistor Q9 is connected to the first end of the ninth resistor R9, and the second end of the ninth resistor R9 is respectively connected to the first end of the tenth resistor R10, the first pole of the third voltage stabilizing diode D3 and the gate of the eighth transistor Q8. The ninth resistor R9 can be used as a current limiting resistor of the eighth transistor Q8, and the ninth resistor R9 is used to limit the driving current of the eighth transistor Q8 to achieve current limiting protection for the eighth transistor Q8. The second end of the tenth resistor R10 and the second pole of the third voltage stabilizing diode D3 are both connected to the source of the eighth transistor Q8, the source of the eighth transistor Q8 is also connected to the DC power supply, and the drain of the eighth transistor Q8 is connected to the load.

[0070] In the present embodiment, the first pole of the third voltage stabilizing diode D3 may be the cathode of the third voltage stabilizing diode D3, and the second pole of the third voltage stabilizing diode D3 may be the anode of the third voltage stabilizing diode D3. The eighth transistor Q8 may be connected between the DC power supply and the load, and the on-off control of the connection between the DC power supply and the load may be realized by changing the on-off of the eighth transistor Q8. The third voltage stabilizing diode D3 is connected between the gate and the source of the eighth transistor Q8, and may be used to realize the voltage stabilization of the eighth transistor Q8, and protect the eighth transistor Q8 from being damaged by high voltage. Preferably, a voltage stabilizing diode with a voltage stabilization value of about 5V may be selected as the third voltage stabilizing diode D3. The tenth resistor R10 is connected in parallel at both ends of the third voltage stabilizing diode D3, so that the current in the circuit can be smoothly controlled, thereby further realizing voltage stability.

[0071] In one embodiment, see Figure 4 , when the DC power supply is a negative power supply, the target DC signal -VOUT output by the DC power supply is a negative DC voltage. The first transistor Q1, the second transistor Q2, the third transistor Q3, the fifth transistor Q5, the sixth transistor Q6, the seventh transistor Q7 and the eighth transistor Q8 can all be N-type transistors, and the fourth transistor Q4 and the ninth transistor Q9 can all be P-type transistors. That is, the first transistor Q1, the second transistor Q2, the third transistor Q3, the fifth transistor Q5, the sixth transistor Q6, the seventh transistor Q7 and the eighth transistor Q8 are turned on according to a high level and turned off according to a low level, and the fourth transistor Q4 and the ninth transistor Q9 are turned on according to a low level and turned off according to a high level, so that the DC short-circuit protection circuit can use the conduction characteristics of each transistor in the circuit to achieve short-circuit protection of the DC negative power supply.

[0072] In addition, in practical applications, the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, and the eleventh resistor R11 can be adaptively designed according to different application requirements. Similarly, the capacitance value of the first capacitor C1 can also be adaptively designed according to requirements.

[0073] In this embodiment, Figure 5 Taking the DC short-circuit protection circuit shown as an example, its working process is explained. The description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. Figure 4 In the figure, +5V is the high level provided by the auxiliary power supply, GND is the reference 0V of the circuit, V-_EN is the reference signal, the potential at point A is high when the switch unit 210 is turned on, and the potential at point A is low when the switch unit 210 is turned off. -VIN can be the DC input terminal of the DC short circuit protection circuit, -VIN can be connected to a DC power supply, -VOUT can be the DC output terminal of the DC short circuit protection circuit, and -VOUT can be connected to a load. Among them, the DC power supply can be a DC positive power supply. The low level is a level signal close to 0V, and the voltage regulation value of the first Zener diode D1 and the second Zener diode D2 is about 5V. V-_Alarm can be connected to the alarm module 400, and when V-_Alarm is high, it is regarded as an output alarm signal, and when V-_Alarm is low, there is no alarm signal.

[0074] Embodiment 5: When the switch unit 210 is turned off, the potential at point A is low, and the gate of the seventh transistor Q7 is low, so the seventh transistor Q7 is turned off. Thus, the level at the gate of the ninth transistor Q9 is high, and the ninth transistor Q9 is turned off. Further, the gate of the eighth transistor Q8 is low, so the eighth transistor Q8 is also turned off, and the connection between the DC input terminal of the DC short-circuit protection circuit and the DC output terminal of the DC short-circuit protection circuit is disconnected. At the same time, since the potential at point A is low, the gate of the first transistor Q1 is also low, so the first transistor Q1 is turned off, and the +5V high level provided by the auxiliary power supply is transmitted to the gate of the second transistor Q2 through the second resistor R2, so that the gate of the second transistor Q2 is high, and the second transistor Q2 is turned on. After the second transistor Q2 is turned on, it is grounded, pulling down the potential at V-_Alarm. Therefore, the DC short-circuit protection circuit does not output an alarm signal at this time.

[0075] Embodiment 6: The switch unit 210 is turned on when the DC power supply has no short-circuit problem. After the switch unit 210 is turned on, the potential at point A is high, and the gate of the seventh transistor Q7 is high, and the seventh transistor Q7 is turned on. After the seventh transistor Q7 is turned on, it is grounded, pulling down the potential at the gate of the ninth transistor Q9, so that the ninth transistor Q9 is turned on. After the ninth transistor Q9 is turned on, the +5V high level provided by the auxiliary power supply is transmitted to the gate of the eighth transistor Q8, so that the eighth transistor Q8 is turned on, and the connection between the DC power supply and the load is turned on. At the same time, since the potential at point A is high, after the switch unit 210 is turned on for t seconds, the first capacitor C1 is charged for t seconds, and the potential at the gate of the first transistor Q1 is also high, so the first transistor Q1 is turned on. After the first transistor Q1 is turned on, it is grounded, pulling down the potential at the gate of the second transistor Q2, and the second transistor Q2 is turned off.

[0076] At the same time, since the eighth transistor Q8 is turned on, the DC input terminal of the DC short circuit protection circuit and the DC output terminal of the DC short circuit protection circuit are turned on, therefore, at this time, there is a negative voltage at -VOUT (which may be a negative voltage less than -1.5V), so that the fifth transistor Q5 is turned on. After the fifth transistor Q5 is turned on, the potential at the gate of the fourth transistor Q4 is pulled down, and therefore, the fourth transistor Q4 is turned on. After the fourth transistor Q4 is turned on, the +5V high level provided by the auxiliary power supply is transmitted to the gate of the third transistor Q3, and the potential of the gate of the third transistor Q3 is also a high level, and the third transistor Q3 is turned on. After the third transistor Q3 is turned on, it is grounded and the potential at V-_Alarm is pulled down. Therefore, the DC short circuit protection circuit does not output an alarm signal at this time.

[0077] Embodiment 7: The switch unit 210 is turned on when the DC power supply has no short-circuit problem, and after the switch unit 210 is turned on for a period of time, the DC power supply suddenly short-circuits. The startup process of the switch unit 210 when the DC power supply has no short-circuit problem is the same as that of Embodiment 6, which is not described in detail here. When the power supply is turned on normally and works for a period of time, -VOUT is short-circuited to GND, that is, -VOUT is at a low level. At this time, the fifth transistor Q5 is turned off, so that the fourth transistor Q4 and the third transistor Q3 are also turned off, so that V-_Alarm becomes a high level, and the DC short-circuit protection circuit outputs an alarm signal.

[0078] At the same time, since V-_Alarm is at a high level, the potential at the gate of the sixth transistor Q6 is also at a high level, and the sixth transistor Q6 is turned on. After the sixth transistor Q6 is turned on, it is grounded, pulling down the potential at the gate of the seventh transistor Q7, and the seventh transistor Q7 is turned off. After the seventh transistor Q7 is turned off, the potential at the gate of the ninth transistor Q9 becomes a high level, so that the ninth transistor Q9 is turned off. After the ninth transistor Q9 is turned off, the gate of the eighth transistor Q8 becomes a low level, so the eighth transistor Q8 is turned off. After the eighth transistor Q8 is turned off, the connection between the DC input terminal of the DC short-circuit protection circuit and the DC output terminal of the DC short-circuit protection circuit is disconnected. Since the turn-on and turn-off time of the transistor is very short, at the nanosecond level, the above-mentioned DC short-circuit protection circuit can also quickly shut down the path and send an alarm signal for a sudden short circuit of the DC negative power supply.

[0079] Embodiment 8: The switch unit 210 is turned on when the DC power supply has a short circuit problem. After the switch unit 210 is turned on, the potential at point A is high, and the gate of the seventh transistor Q7 is high, and the seventh transistor Q7 is turned on. After the seventh transistor Q7 is turned on, it is grounded, pulling down the potential of the gate of the ninth transistor Q9, so that the ninth transistor Q9 is turned on. After the ninth transistor Q9 is turned on, the +5V high level provided by the auxiliary power supply is transmitted to the gate of the eighth transistor Q8, so that the eighth transistor Q8 is turned on, and the connection between the DC power supply and the load is turned on.

[0080] Since the potential at point A is high, after the switch unit 210 is turned on for t seconds and the first capacitor C1 is charged for t seconds, the potential at the gate of the first transistor Q1 is also high, so the first transistor Q1 is turned on. After the first transistor Q1 is turned on, it is grounded, lowering the potential at the gate of the second transistor Q2, and the second transistor Q2 is turned off.

[0081] At the same time, since the eighth transistor Q8 is turned on, the DC input terminal of the DC short circuit protection circuit and the DC output terminal of the DC short circuit protection circuit are turned on. At this time, since the DC power supply is short-circuited, -VOUT is at a low level, so that the fifth transistor Q5 is not turned on, and further, the fourth transistor Q4 and the third transistor Q3 are not turned on. At this time, the potential of V-_Alarm is at a high level, that is, the DC short circuit protection circuit outputs an alarm signal.

[0082] Since V-_Alarm is at a high level, the potential at the gate of the sixth transistor Q6 is also at a high level, and the sixth transistor Q6 is turned on. After the sixth transistor Q6 is turned on, it is grounded, pulling down the potential at the gate of the seventh transistor Q7, and the seventh transistor Q7 is turned off. After the seventh transistor Q7 is turned off, the potential at the gate of the ninth transistor Q9 becomes a high level, so that the ninth transistor Q9 is turned off. After the ninth transistor Q9 is turned off, the gate of the eighth transistor Q8 becomes a low level, so the eighth transistor Q8 is turned off. After the eighth transistor Q8 is turned off, the connection between the DC input terminal of the DC short-circuit protection circuit and the DC output terminal of the DC short-circuit protection circuit is disconnected.

[0083] It can be seen that the above DC short-circuit protection circuit realizes short-circuit detection for the DC negative power supply based on voltage. At the same time, the transistor used in the DC short-circuit protection circuit has the characteristic of low internal resistance, which can make the circuit have relatively small loss and does not increase the consumption of the main circuit. At the same time, since the above DC short-circuit protection circuit can be built using discrete components, fewer components are used, and commonly used components such as transistors, voltage regulators, resistors, capacitors, etc. are used, it also has the advantage of low circuit cost.

[0084] Similarly, in the present embodiment, the comparison module 200 in the DC short circuit protection circuit can also close the switch unit 210 based on the reset instruction, so that the delay comparison unit 220 resets the shutdown signal. Specifically, after a short circuit problem occurs in the DC power supply, and the DC short circuit protection circuit quickly shuts off the path and sends an alarm signal. Even after the short circuit problem of the DC power supply is solved, since the first capacitor C1 completes the charging at the initial stage of the circuit opening, the potential of the gate of the first transistor Q1 can be maintained, so that the first transistor Q1 is turned on, the first transistor Q1 is grounded after turning on, and the potential at the gate of the second transistor Q2 is pulled down, and the second transistor Q2 is turned off. At the same time, the third transistor Q3 is also in the off state, which shows that even after the short circuit problem is removed, the DC short circuit protection circuit still remains in the short circuit protection state, and V-_Alarm continues to be a high level, that is, the DC short circuit protection circuit continues to output an alarm signal.

[0085] It can be seen that the above-mentioned DC short-circuit protection circuit can not only quickly shut down the power supply path for short-circuit problems, but also self-lock after detecting the short-circuit problem and maintain it in the short-circuit protection state. The user needs to restore it to the normal state through a reset instruction, thereby further improving the safety factor of the circuit.

[0086] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0087] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. The above-mentioned embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A DC short-circuit protection circuit, characterized in that: include: A sampling module, used for sampling a target DC signal output by the DC power supply; a comparison module, connected to the sampling module, for receiving a reference signal, and for determining whether the DC power supply is short-circuited according to a comparison between the target DC signal and the reference signal, and outputting a shutdown signal in response to a comparison result that the DC power supply is short-circuited; a switch control module, connected to the comparison module and also connected between the DC power supply and the load, the switch control module being used to disconnect the path between the DC power supply and the load according to the shutdown signal; The comparison module comprises: A switch unit, connected between the reference power supply and the comparison module, and used to control the on / off connection between the reference power supply and the comparison module; a delay comparison unit, connected to the switch unit and the sampling module respectively, and receiving the reference signal after a preset time delay after the switch unit controls the connection between the reference power supply and the comparison module, judging whether the DC power supply is short-circuited according to the comparison between the target DC signal and the reference signal, and outputting a shutdown signal in response to the comparison result that the DC power supply is short-circuited; The delay comparison unit includes a first resistor, a second resistor, a first capacitor, a first transistor and a second transistor. A first end of the first resistor is connected to the switch unit, a second end of the first resistor is connected to the gate of the first transistor, the first capacitor is connected between the gate of the first transistor and the source of the first transistor, a first end of the second resistor is connected to the drain of the first transistor, and a second end of the second resistor is connected to an auxiliary power supply. The gate of the second transistor is connected to the second end of the second resistor, the drain of the second transistor is connected to the sampling module and the switch control module, and the source of the first transistor and the source of the second transistor are both grounded; The DC power supply is a positive power supply, and the sampling module includes a third resistor, a fourth resistor, a third transistor and a first voltage regulator diode. The first end of the third resistor is connected to the auxiliary power supply, the second end of the third resistor is respectively connected to the switch control module, the delay comparison unit and the drain of the third transistor, the gate of the third transistor is respectively connected to the first end of the fourth resistor and the first electrode of the first voltage zener diode, the source of the third transistor is respectively connected to the second electrode of the first voltage zener diode and the ground, and the second end of the fourth resistor is connected to the load; The DC power supply is a positive power supply, and the switch control module includes an eighth resistor, a ninth resistor, a tenth resistor, a sixth transistor, a seventh transistor, an eighth transistor, and a third voltage-stabilizing diode. The first end of the eighth resistor is connected to the switch unit, the second end of the eighth resistor is respectively connected to the drain of the sixth transistor and the gate of the seventh transistor, the gate of the sixth transistor is respectively connected to the delay comparison unit and the sampling module, the source of the sixth transistor and the source of the seventh transistor are both grounded, The drain of the seventh transistor is connected to the first end of the ninth resistor, the second end of the ninth resistor is respectively connected to the first end of the tenth resistor, the second electrode of the third voltage-regulating diode and the gate of the eighth transistor, the second end of the tenth resistor and the first electrode of the third voltage-regulating diode are both connected to the source of the eighth transistor, the source of the eighth transistor is also connected to the DC power supply, and the drain of the eighth transistor is connected to the load.

2. The DC short-circuit protection circuit according to claim 1, characterized in that: The comparison module is further configured to output an alarm signal in response to the comparison result of the DC power supply short circuit, and the DC short circuit protection circuit further comprises: An alarm module is connected to the comparison module and is used to generate alarm information according to the alarm signal.

3. The DC short-circuit protection circuit according to claim 1, characterized in that: The comparison module is further configured to reset the shutdown signal in response to a reset instruction.

4. The DC short-circuit protection circuit according to claim 1, characterized in that: The DC power supply is a negative power supply, and the sampling module includes a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a third transistor, a fourth transistor, a fifth transistor, a first voltage regulator diode and a second voltage regulator diode. The first end of the third resistor is connected to the auxiliary power supply, the second end of the third resistor is respectively connected to the switch control module, the delay comparison unit and the drain of the third transistor, the gate of the third transistor is respectively connected to the first end of the fourth resistor and the drain of the fourth transistor, the source of the third transistor is respectively connected to the second end of the fourth resistor and the ground, the gate of the fourth transistor is respectively connected to the second electrode of the first voltage zener diode, the first end of the fifth resistor and the first end of the sixth resistor, the source of the fourth transistor is respectively connected to the first electrode of the first voltage zener diode, the second end of the sixth resistor and the auxiliary power supply, The second end of the fifth resistor is connected to the drain of the fifth transistor, the gate of the fifth transistor is respectively connected to the first end of the seventh resistor and the first electrode of the second zener diode, and the source of the fifth transistor is respectively connected to the second electrode of the second zener diode and the load.

5. The DC short-circuit protection circuit according to claim 1, characterized in that: The DC power supply is a negative power supply, and the switch control module includes an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a sixth transistor, a seventh transistor, an eighth transistor, a ninth transistor, and a third voltage stabilizing diode. The first end of the eighth resistor is connected to the switch unit, the second end of the eighth resistor is respectively connected to the drain of the sixth transistor and the gate of the seventh transistor, the gate of the sixth transistor is respectively connected to the delay comparison unit and the sampling module, the source of the sixth transistor and the source of the seventh transistor are both grounded, The drain of the seventh transistor is respectively connected to the first end of the eleventh resistor and the gate of the ninth transistor, the second end of the eleventh resistor and the source of the ninth transistor are both connected to the auxiliary power supply, the drain of the ninth transistor is connected to the first end of the ninth resistor, the second end of the ninth resistor is respectively connected to the first end of the tenth resistor, the first electrode of the third voltage-regulating diode and the gate of the eighth transistor, the second end of the tenth resistor and the second electrode of the third voltage-regulating diode are both connected to the source of the eighth transistor, the source of the eighth transistor is also connected to the DC power supply, and the drain of the eighth transistor is connected to the load.

6. The DC short-circuit protection circuit according to any one of claims 4 to 5, characterized in that: When the DC power supply is a positive power supply, the first transistor, the second transistor, the third transistor, the sixth transistor and the seventh transistor are all N-type transistors, and the eighth transistor is a P-type transistor; when the DC power supply is a negative power supply, the first transistor, the second transistor, the third transistor, the fifth transistor, the sixth transistor, the seventh transistor and the eighth transistor are all N-type transistors, and the fourth transistor and the ninth transistor are all P-type transistors.

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