Direct-current switching power supply and short-circuit protection circuit thereof

Abstract

The utility model discloses a DC switching power supply and a short-circuit protection circuit thereof, the short-circuit protection circuit comprises a switch module, a protection module, a short-circuit detection module, a trigger module and a control module, and the short-circuit detection module outputs a short-circuit trigger signal when detecting that a power supply circuit is short-circuited; when receiving the short circuit trigger signal, the trigger module outputs a disconnection control signal to the protection module; the control module outputs a reset signal to the trigger module when receiving a short circuit removing signal of the power supply circuit through the protection module, so that the trigger module outputs a conduction control signal to the protection module. According to the technical scheme, when short circuit occurs, the power supply circuit can be cut off, after the short circuit is removed, the trigger module is automatically restarted, the trigger module triggers the protection module to be conducted again, power supply is restored, manual intervention is not needed in the whole process, and the safety and convenience of equipment are effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to switch power supply technical field especially relates to a direct current switch power supply and short circuit protection circuit thereof. BACKGROUND

[0002] With the wide application and development of electronic product equipment in various trades, its reliability and stability gradually become one of the important basic demands. Since the switch power supply has the advantages of high efficiency, small size, light weight, etc., it is widely used in electronic equipment, and various voltages are generally converted through the switch power supply circuit. However, during the operation of the electronic equipment, the switch power supply may be caused by various internal or external reasons to cause short circuit failure. After short circuit, the components in the circuit are often damaged and burned out, eventually leading to the unrecoverable failure of the equipment. The protection function of the power supply circuit as an important technical index in power supply design has attracted great attention. In order to avoid the burning of parts due to the short circuit of the power supply, a circuit capable of quickly responding and effectively protecting the equipment becomes urgently needed.

[0003] The prior art scheme adopts a short circuit protection circuit based on the input voltage feedback of the switch power supply. The circuit divides the input voltage Vout of the switch power supply through a resistor to obtain a feedback signal, and places the divided signal into the inverter circuit. The inverter is composed of a transistor Q1, which feeds back the divided feedback signal to control the conduction and shutdown of the transistor, thereby controlling the output of the power supply chip LM2576. When the output end Vout of the power supply and the ground (GA) are short-circuited, the inverter outputs a high level signal, the LM2576 stops working, and the output voltage Vout is turned off, realizing the short circuit protection function.

[0004] However, the prior art scheme has obvious defects: it cannot realize the automatic recovery function after the short circuit fault is eliminated, which requires manual intervention after the short circuit fault is eliminated, reducing the automation degree of the system. UTILITY MODEL CONTENTS

[0005] The utility model embodiment provides a kind of direct current switch power supply and short circuit protection circuit thereof to solve above-mentioned technical problem.

[0006] The utility model embodiment first aspect provides a kind of short circuit protection circuit of direct current switch power supply, comprising:

[0007] Switch module, its one end receives input power supply;

[0008] Protection module, one end of the other end of the switch module is connected to form power supply circuit with the switch module;

[0009] a short-circuit detection module, an output end of which is connected to an output end of the power supply circuit, so as to output a short-circuit trigger signal when the power supply circuit is short-circuited;

[0010] a trigger module, an input end of which is connected to an output end of the short-circuit detection module, and an output end of which is connected to a control end of the protection module, so as to output an open control signal to the protection module when the trigger module receives the short-circuit trigger signal;

[0011] a control module, an input end of which is connected to the other end of the protection module, and an output end of which is connected to a control end of the trigger module, so as to output a reset signal to the trigger module when the control module receives a short-circuit release signal of the power supply circuit from the protection module, and so as to make the trigger module output a conductive control signal to the protection module.

[0012] Optionally, the protection module comprises:

[0013] a relay, a normally closed contact of which is one end of the protection module, and a normally open contact of which is the other end of the protection module;

[0014] when the power supply circuit is short-circuited, the normally open contact has a voltage of 0;

[0015] when the power supply circuit is short-circuit released, the normally open contact has a voltage not equal to 0.

[0016] Optionally, the short-circuit detection module comprises:

[0017] an operational amplifier unit, an input end of which is connected to the power supply circuit, so as to collect a current in the power supply circuit and convert the collected current into a collected voltage;

[0018] a comparison unit, a first input end of which is connected to an output end of the operational amplifier unit, and a second input end of which receives a preset voltage, so as to output a short-circuit trigger signal when the collected voltage is greater than the preset voltage.

[0019] Optionally, the control module comprises a control chip and a first switch unit, an input end of the control chip is the input end of the control module, an input end of the control chip is connected to the other end of the protection module, a first output end of the control chip is connected to a control end of the first switch unit, one end of the first switch unit is connected to a control end of the trigger module, and the other end of the first switch unit is grounded.

[0020] Optionally, the control module is further connected to the output end of the trigger module, the control module further comprises a first light emitting diode and a second light emitting diode, the second output end of the control chip is connected to the anode of the first light emitting diode, the third output end of the control chip is connected to the anode of the second light emitting diode, the cathode of the first light emitting diode and the cathode of the second light emitting diode are grounded.

[0021] Optionally, the short-circuit protection circuit further comprises:

[0022] a second switch unit, a control end of the second switch unit is connected to the output end of the trigger module, one end of the second switch unit is connected to the control end of the protection module, and the other end of the second switch unit is grounded.

[0023] Optionally, the short-circuit protection circuit further comprises:

[0024] a driving module, an input end of the driving module is connected to the output end of the trigger module, and an output end of the driving module is connected to the control end of the switch module, so as to control the switch module to be turned off when the disconnection control signal is received and control the switch module to be turned on when the conduction control signal is received.

[0025] Optionally, the operational amplification unit comprises an operational amplifier U3, a resistor R31, a resistor R33, a resistor R36, a resistor R37, a resistor R38, a resistor R39 and a capacitor C34, one end of the resistor R33 is a first input end of the operational amplification unit, one end of the resistor R36 is a second input end of the operational amplification unit, the other end of the resistor R33 is connected to one end of the resistor R31, one end of the capacitor C34 and an inverting input end of the operational amplifier U3 respectively, the other end of the resistor R36 is connected to one end of the resistor R37, the other end of the capacitor C34 and a non-inverting input end of the operational amplifier U3 respectively, a voltage end of the operational amplifier U3 receives a first voltage, a ground end of the operational amplifier U3, the other end of the resistor R37 and one end of the resistor R38 are grounded, the other end of the resistor R38 is connected to one end of the resistor R39, the other end of the resistor R39 receives a first voltage, and an output end of the operational amplifier U3 and the other end of the resistor R31 are connected to each other as an output end of the operational amplification unit.

[0026] Optionally, the comparison unit comprises a comparison chip U2, a resistor R35, a resistor R34 and a capacitor C33, one end of the resistor R35 and one end of the capacitor C33 are connected to the first end of the comparison chip U2, the other end of the resistor R35 is the first input end of the comparison unit, the other end of the capacitor C33 is grounded, the second end of the comparison chip U2 is connected to the other end of the resistor R38 and one end of the resistor R39, the voltage end of the comparison chip U2 and one end of the resistor R34 are connected together to receive the first voltage, and the output end of the comparison chip U2 and the other end of the resistor R34 are connected together to be the output end of the comparison unit.

[0027] The utility model embodiment second aspect provides a kind of DC switching power supply, comprising: the short circuit protection circuit of the first aspect and input power supply, the input power supply connects one end of the switching module.

[0028] The technical effects of the utility model embodiment are: when short circuit occurs, the short circuit detection module can quickly and accurately detect the short circuit state, and sends the disconnect control signal to the protection module through the trigger module, immediately cuts off the power supply to prevent short circuit from damaging the equipment. This automatic detection and disconnection mechanism realizes the safety and reliability of the circuit. At the same time, when the short circuit is removed, the control module can receive the short circuit removal signal, automatically send the reset signal to the trigger module, so that the trigger module triggers the protection module to re-conduct, and the power supply is restored. The whole process does not need manual intervention, realizes the automatic detection, automatic disconnection and automatic recovery function of short circuit protection, greatly improves the operation efficiency of the system, and effectively improves the safety and convenience of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical scheme of the utility model embodiment, the drawings needed to be used in the description of the utility model embodiment will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0030] Figure 1 is the first kind of structure schematic view of the short circuit protection circuit of a DC switching power supply provided by the utility model embodiment one;

[0031] Figure 2 is the structure schematic view of the short circuit detection module in the short circuit protection circuit of a DC switching power supply provided by the utility model embodiment one;

[0032] Figure 3 is the first kind of structure schematic view of the control module in the short circuit protection circuit of a DC switching power supply provided by the utility model embodiment one.

[0033] Figure 4 is a second structure schematic view of a control module in a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0034] Figure 5 is a second structure schematic view of a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0035] Figure 6 is a third structure schematic view of a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0036] Figure 7 is a circuit diagram of a power supply circuit in a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0037] Figure 8 is a circuit diagram of a driving module in a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0038] Figure 9 is a circuit diagram of a second switch unit in a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0039] Figure 10 is a circuit diagram of a short-circuit detection module and a trigger module in a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0040] Figure 11 is a circuit diagram of a control module in a short-circuit protection circuit of a direct-current switching power supply provided by the embodiment one of the utility model;

[0041] Figure 12 is a structure schematic view of a direct-current switching power supply provided by the embodiment two of the utility model.

[0042] In the drawing: 101, switch module;102, protection module;103, short-circuit detection module;104, trigger module;105, control module;131, operational amplifier unit;132, comparison unit;151, control chip;152, first switch unit;153, first light-emitting diode;154, second light-emitting diode;106, second switch unit;107, driving module. DETAILED DESCRIPTION

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0044] It should be understood that this invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this invention to those skilled in the art. In the drawings, for clarity, the dimensions of layers and regions, as well as their relative dimensions, may be exaggerated. The same reference numerals denote the same elements throughout.

[0045] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this utility model, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0047] To fully understand this utility model, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this utility model. Preferred embodiments of this utility model are described in detail below; however, in addition to these detailed descriptions, this utility model may have other embodiments.

[0048] Embodiment One

[0049] The embodiment one provides a short circuit protection circuit of a direct current switching power supply, as shown in the figure, comprising: Figure 1

[0050] a switch module 101, one end of which receives an input power VIN;

[0051] a protection module 102, one end of which is connected to the other end of the switch module 101 to form a power supply circuit with the switch module 101;

[0052] a short circuit detection module 103, the detection end of which is connected to the output end VOUT of the power supply circuit to detect the short circuit of the power supply circuit and output a short circuit trigger signal;

[0053] a trigger module 104, the input end of which is connected to the output end of the short circuit detection module 103, and the output end of which is connected to the control end of the protection module 102, when the trigger module 104 receives the short circuit trigger signal, the trigger module 104 outputs a disconnect control signal to the protection module 102;

[0054] a control module 105, the input end of which is connected to one end of the protection module 102, and the output end of which is connected to the control end of the trigger module 104, when the control module 105 receives the signal that the power supply circuit returns to normal through the protection module 102, the control module 105 outputs a reset signal to the trigger module 104, so that the trigger module 104 outputs a conductive control signal to the protection module 102.

[0055] The switch module 101 is used to receive the input power VIN to provide a direct current power supply input for the whole circuit. One end of the switch module 101 receives the input power, and the other end is connected to the protection module 102 to form a power supply circuit. When the power supply is normal, the switch module 101 outputs power through the power supply circuit. The protection module 102 controls the disconnection or conduction of the circuit to protect the circuit from damage caused by short circuit. In the normal power supply state, the protection module 102 maintains the conduction of the circuit. Once the short circuit detection module 103 detects the short circuit, the protection module 102 will disconnect the circuit under the control of the trigger module 104. When the short circuit fault is removed, the control module 105 sends a reset signal to the trigger module 104, and the trigger module 104 triggers the protection module 102 to re-conduct the power supply.

[0056] ​The short-circuit detection module 103 is configured to detect whether a short circuit occurs in the circuit and output a short-circuit trigger signal when the short circuit occurs. Specifically, the short-circuit detection module 103 monitors the current or voltage state of the power supply circuit. When a short-circuit signal (usually a current that is too large or a voltage that is too low) is detected, the short-circuit trigger signal is output to notify the trigger module 104 that a short circuit has occurred. When the short-circuit trigger signal is output by the short-circuit detection module 103, the trigger module 104 receives the signal and outputs a disconnection control signal to the protection module 102, so that the protection module 102 interrupts the power supply circuit. After the reset signal is output by the control module 105, the trigger module 104 sends a conduction signal to the protection module 102, so that the power supply is restarted.

[0057] The control module 105 is configured to detect the state of the protection module 102 and output a reset signal after the short circuit is removed, so as to control the trigger module 104 to restore the normal power supply state of the circuit. When the protection module 102 receives a signal that the power supply circuit has returned to normal, the control module 105 identifies that the short-circuit state of the circuit has been removed and outputs a reset signal to the trigger module 104. After receiving the reset signal, the trigger module 104 sends a conduction signal to the protection module 102 to restore the normal working state of the power supply circuit.

[0058] The working process of the embodiment is as follows: the switch module 101 connects the power supply, the protection module 102 is in a conduction state, and the power supply is normally powered. The short-circuit detection module 103 detects a short circuit and outputs a short-circuit trigger signal. The trigger module 104 receives the short-circuit trigger signal and controls the protection module 102 to disconnect the circuit and cut off the power supply. The control module 105 monitors the state of the protection module 102 and outputs a reset signal after confirming that the short circuit is removed. The trigger module 104 receives the reset signal and controls the protection module 102 to conduct again to restore the normal power supply.

[0059] The technical effect of the embodiment is that when a short circuit occurs, the short-circuit detection module can quickly and accurately detect the short-circuit state and send a disconnection control signal to the protection module through the trigger module to immediately cut off the power supply and prevent damage to the equipment caused by the short circuit. This automatic detection and disconnection mechanism realizes the safety and reliability of the circuit. At the same time, when the short circuit is removed, the control module can receive a short-circuit removal signal and automatically send a reset signal to the trigger module to trigger the protection module to conduct again to restore the power supply. The entire process does not require manual intervention, realizes the functions of automatic detection, automatic disconnection, and automatic recovery of the short-circuit protection, greatly improves the operation efficiency of the system, and effectively improves the safety and convenience of the equipment.

[0060] As an embodiment of the protection module 102, the protection module 102 comprises: a relay, the normally closed contact of the relay being one end of the protection module 102, the normally closed contact of the relay being connected to the other end of the switch module 101, the other end of the protection module 102 being the other end of the normally open contact of the relay; when the power supply circuit is short-circuited, the voltage of the normally open contact is 0; when the short circuit of the power supply circuit is removed, the voltage of the normally open contact is not 0.

[0061] In the short-circuit protection circuit, the protection module 102 mainly realizes the opening and recovery of the circuit through the relay. The relay controls the on-off of the power supply circuit through the switching of its normally closed and normally open contacts. When the power supply circuit is short-circuited, the relay switches to the off state to protect the circuit; when the short circuit is removed, the relay receives the change of the signal through its normally open contact, so that the control module 105 detects the short circuit removal signal and turns on the circuit again. When the short circuit occurs, the output end voltage of the power supply circuit drops to 0, and the normally open contact of the relay is also 0V. The control module 105 performs corresponding actions, for example, displays the short circuit state through a light-emitting diode. When the short circuit is removed, the power supply circuit returns to normal, and the output end voltage is no longer 0V. The control module 105 sends a reset signal to the trigger module 104. The trigger module 104 receives the reset signal and controls the protection module 102 to turn on again, restoring normal power supply.

[0062] The technical effect of the embodiment is that when the short circuit is removed, the output end voltage of the power supply circuit returns to normal, and the voltage of the normally open contact of the relay is no longer 0V. The control module detects the short circuit removal trigger reset signal, and the trigger module receives the reset signal, and then controls the protection module to turn on the circuit again, restoring normal power supply. This automatic recovery mechanism can restore normal power supply without manual intervention after the short circuit is removed, improving the intelligence and self-recovery ability of the circuit. Compared with the traditional protection design relying on manual or single-chip microcomputer, the circuit has a closed-loop mechanism of automatic opening, indication and recovery, making the system have higher reliability and intelligent level.

[0063] As an embodiment of the short circuit detection module 103, as shown in Figure 2 the short circuit detection module 103 comprises:

[0064] an operational amplification unit 131, the input end of which is connected to the power supply circuit to collect the current in the power supply circuit and convert the collected current into a collected voltage;

[0065] a comparison unit 132, the first input end of which is connected to the output end of the operational amplification unit 131, and the second input end of which receives a preset voltage to output a short circuit trigger signal when the collected voltage is greater than the preset voltage.

[0066] The main function of the operational amplification unit 131 is to detect the current signal in the power supply circuit and convert it into a voltage signal, thereby providing an effective voltage input signal for short circuit detection. The input end of the operational amplification unit 131 is connected to the power supply circuit and senses the current through a current sampling resistor or the like. The operational amplification unit 131 amplifies the collected current signal and converts it into a proportional voltage signal output to the comparison unit 132. The larger the current, the higher the converted voltage. The function of the comparison unit 132 is to monitor the voltage signal output by the operational amplification unit 131 in real time and determine whether a short circuit occurs in the circuit. The first input end of the comparison unit 132 is connected to the output end of the operational amplification unit 131 to receive the amplified voltage signal. The second input end of the comparison unit 132 is connected to the reference voltage value V0. The comparison unit 132 compares the voltage signal with the preset voltage threshold value. When the voltage signal exceeds the threshold value (i.e., the current is too large, indicating that a short circuit may exist), the comparison unit 132 immediately outputs a short circuit trigger signal to notify the subsequent protection module 102 to perform a protection operation.

[0067] The technical effect of the embodiment is that the operational amplification unit amplifies and converts the current signal, improving the accuracy of short circuit detection. The comparison unit can quickly respond to short circuit conditions through threshold comparison, ensuring that protection measures can be triggered immediately when a short circuit occurs, thereby ensuring system safety. Through current-voltage conversion and threshold comparison, a high-efficiency and simple short circuit detection module is formed, which has better sensitivity compared to direct current detection.

[0068] As an embodiment of the control module 105, as shown in Figure 3 The control module 105 includes a control chip 151 and a first switch unit 152. The input end of the control chip 151 is the input end of the control module 105. The input end of the control chip 151 is connected to the other end of the protection module 102. The first output end of the control chip 151 is connected to the control end of the first switch unit 152. One end of the first switch unit 152 is connected to the control end of the trigger module 104, and the other end of the first switch unit 152 is grounded. When the control chip 151 receives the short circuit removal signal, the first switch module 101 is turned on, and the control end of the trigger module 104 is grounded. After the trigger module 104 receives the low-level signal, it is reset and starts working again.

[0069] The control chip 151 receives the short-circuit removal signal and outputs a control signal to the first switch unit 152 to control the circuit reset. When the control chip 151 receives the short-circuit removal signal, it is identified that the power supply circuit has returned to normal. The first output end of the control chip 151 outputs the control signal to the first switch unit 152, so that the first switch unit 152 is turned on. The main function of the first switch unit 152 is to receive the control signal from the control chip 151, and to turn on when the short circuit is removed, so as to ground the control end of the trigger module 104, thereby resetting the trigger module 104 and restoring the normal working state. The trigger module 104 is used to receive the reset signal from the first switch unit 152, to turn on the protection module 102 again after the short circuit is removed, and to restore the normal power supply.

[0070] The technical effect of the embodiment is that the control chip can automatically identify the short-circuit removal signal and issue a reset instruction, the first switch unit quickly responds to the control chip signal, and the trigger module quickly recovers work through the reset instruction, thereby ensuring that the circuit quickly recovers normal power supply after the short circuit is removed. The modular design ensures that the circuit state is automatically switched when the short circuit occurs and is removed, without manual intervention, thereby effectively improving the stability and continuity of the circuit.

[0071] As an embodiment, as shown in Figure 4 The control module 105 further includes a first light-emitting diode 153 and a second light-emitting diode 154. The second output end of the control chip 151 is connected to the anode of the first light-emitting diode 153, the third output end of the control chip 151 is connected to the anode of the second light-emitting diode 154, and the cathode of the first light-emitting diode 153 and the cathode of the second light-emitting diode 154 are grounded. When the control chip 151 detects the disconnection control signal, the first light-emitting diode 153 is controlled to emit light, and the second light-emitting diode 154 is controlled to be extinguished; when the control chip 151 detects the short-circuit removal signal, the second light-emitting diode 154 is controlled to emit light, and the first light-emitting diode 153 is controlled to be extinguished.

[0072] The first light emitting diode 153 is used to indicate the short circuit state of the circuit. When the circuit detects a short circuit and cuts off the power supply, the first light emitting diode 153 is lit to remind the user that the circuit is in a short circuit protection state. When the control chip 151 detects a disconnection control signal (i.e. a short circuit occurs in the circuit), the control chip 151 provides current to the anode of the first light emitting diode 153 through its second output end, so that the first light emitting diode 153 emits light, and the cathode of the first light emitting diode 153 is grounded, completing the current loop. The second light emitting diode 154 is used to indicate the normal working state of the circuit. After the short circuit is removed and the power supply is restored, the second light emitting diode 154 is lit to indicate that the circuit has returned to normal. When the control chip 151 detects a short circuit removal signal, it provides current to the anode of the second light emitting diode 154 through its third output end, the cathode of the second light emitting diode 154 is grounded, completing the current loop, the second light emitting diode 154 emits light, and at the same time the current output of the first light emitting diode 153 is turned off, the first light emitting diode 153 is extinguished. The control chip 151 is responsible for controlling the lighting and extinguishing of the first light emitting diode 153 and the second light emitting diode 154 to display the short circuit and recovery state of the circuit.

[0073] The technical effect of the embodiment is that through the display of the first light emitting diode and the second light emitting diode, the user can intuitively understand the short circuit and normal state of the circuit, which facilitates fault diagnosis and processing, improves the maintenance efficiency, the control chip automatically controls the state of the LED (the first light emitting diode and the second light emitting diode), further enhances the intelligent monitoring function of the circuit, and effectively improves the operability and safety of the system.

[0074] As an embodiment, as shown in Figure 5 The short circuit protection circuit further comprises:

[0075] The second switch unit 106 has a control end connected to the output end of the trigger module 104, one end of the second switch unit 106 connected to the control end of the protection module 102, and the other end of the second switch unit 106 grounded.

[0076] The second switch unit 106 is used to receive the output signal of the trigger module 104 and control the working state of the protection module 102 when a short circuit occurs, so that the circuit quickly enters the protection state and recovers after the short circuit is removed. When the trigger module 104 detects a short circuit and outputs a disconnection control signal, the control end of the second switch unit 106 receives the signal to turn on, so that the control end of the protection module 102 is grounded and the protection module 102 is turned off. In addition, after the short circuit is removed, the trigger module 104 outputs a conduction control signal, and the second switch unit 106 is turned off, so that the protection module 102 returns to the normal working state.

[0077] The technical effect of the embodiment is that the second switch unit controls the state of the protection module, realizes automatic disconnection and recovery of the circuit, ensures quick protection when a short circuit occurs, and recovers immediately after the short circuit is removed.

[0078] As an embodiment, as shown in Figure 6 The short circuit protection circuit further includes a driving module 107, an input end of which is connected to an output end of the triggering module 104, and an output end of which is connected to a control end of the switch module 101, so as to control the switch module 101 to be disconnected when a disconnection control signal is received, and control the switch module 101 to be turned on when a turn-on control signal is received.

[0079] The driving module 107 is configured to receive the control signal output by the triggering module 104, control the on-off of the switch module 101, so as to cut off the circuit when a short circuit occurs, and restore the power supply of the circuit after the short circuit is removed. When the triggering module 104 outputs the disconnection control signal, the driving module 107 is activated, outputs the disconnection signal to the control end of the switch module 101, and cuts off the power supply; when the triggering module 104 outputs the turn-on control signal, the driving module 107 makes the switch module 101 turn on again. The triggering module 104 generates and outputs the disconnection control signal or the turn-on control signal, so as to control the driving module 107 to cut off the circuit when a short circuit occurs, and restore the circuit after the short circuit is removed. When the short circuit detection module 103 detects the short circuit signal, the triggering module 104 generates the disconnection control signal and transmits it to the driving module 107. After receiving the signal, the driving module 107 cuts off the circuit. After the short circuit is removed, the triggering module 104 generates the turn-on control signal, and the driving module 107 restores the power supply of the circuit. The switch module 101 is configured to control the on-off of the power supply circuit, and functions to cut off the short circuit current or restore the power supply.

[0080] The technical effect of the embodiment is that through the coordinated work of the driving module, the triggering module and the switch module, the circuit can quickly cut off the power supply when a short circuit occurs, and automatically recover after the short circuit is removed, without manual intervention. The power supply is cut off when a short circuit occurs, which avoids damage to the circuit elements caused by current impact and prolongs the service life of the equipment. The entire circuit automatically controls the disconnection and recovery of the power supply through signals, realizes the self-protection and self-repair functions of the circuit, and improves the intelligence and stability of the system.

[0081] The embodiment will be described in detail below through a specific circuit structure:

[0082] As shown in Figure 7As shown, the power supply circuit includes a switching module 101 and a protection module 102, the switching module 101 is a MOS tube Q1, the protection module 102 is a relay K1, the power supply circuit further includes a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a diode D1, a diode D2 and an inductor L1, one end of the capacitor C1, one end of the capacitor C4 and the drain of the MOS tube Q1 are commonly connected as an input terminal P1, the source of the MOS tube Q1 is connected to one end of the resistor R2, the cathode of the diode D1, the cathode of the diode D2 and one end of the inductor L1 respectively, the gate of the MOS tube Q1 and the other end of the resistor R2 are commonly connected to receive a PWM signal, the other end of the inductor L1 is connected to one end of the resistor R1, the other end of the resistor R1 is connected to one end of the capacitor C2, one end of the capacitor C3, one end of the capacitor C5 and the common terminal of the relay K1 respectively, the normally closed terminal of the relay K1 is connected to an output terminal P2, the control terminal of the relay K1 receives a JDQ signal, the normally open terminal of the relay K1 is connected to the output terminal P2 in the switching state, the other end of the capacitor C1, the other end of the capacitor C2, the other end of the capacitor C3, the other end of the capacitor C4, the other end of the capacitor C5, the anode of the diode D1, the anode of the diode D2 and one end of the resistor R3 are commonly connected as an input terminal P3, and the other end of the resistor R3 is an output terminal P4.

[0083] As shown in Figure 8 , the driving module 107 includes a chip U4, a resistor R6, a capacitor C6, a diode D3 and a diode D4, the model of the chip U4 can be IR2110, the pin 11 of the chip U4 is used to receive an SD signal, the pin 7 of the chip U4 is connected to one end of the resistor R6 and the cathode of the diode D3 respectively, the other end of the resistor R6 and the anode of the diode D3 are commonly connected to output a PWM signal, the pin 3 of the chip U4 is connected to the anode of the diode D4, the pin 5 of the chip U4 is connected to one end of the capacitor C6, and the pin 6 of the chip U4 is connected to the other end of the capacitor C6 and the cathode of the diode D4 respectively.

[0084] As shown in Figure 9 , the second switching unit 106 includes a triode Q2 and a resistor R7, one end of the resistor R7 is used to receive an SD signal, the other end of the resistor R7 is connected to the base of the triode Q2, the collector of the triode Q2 is used to output a JDQ signal, and the emitter of the triode Q2 is grounded.

[0085] As shown in Figure 10As shown in the figure, the operational amplification unit 131 includes an operational amplifier U3, a resistor R31, a resistor R33, a resistor R36, a resistor R37, a resistor R38, a resistor R39, and a capacitor C34. One end of the resistor R33 is a first input end, one end of the resistor R36 is a second input end, the other end of the resistor R33 is connected to one end of the resistor R31, one end of the capacitor C34, and the inverting input end of the operational amplifier U3, respectively, the other end of the resistor R36 is connected to one end of the resistor R37, the other end of the capacitor C34, and the non-inverting input end of the operational amplifier U3, respectively, the voltage end of the operational amplifier U3 receives a 5V voltage, the ground end of the operational amplifier U3, the other end of the resistor R37, and one end of the resistor R38 are connected to ground, the other end of the resistor R38 is connected to one end of the resistor R39, the other end of the resistor R39 receives a 5V voltage, and the output end of the operational amplifier U3 is connected to the other end of the resistor R31.

[0086] As shown in the figure, Figure 10 the comparison unit 132 includes a comparison chip U2, a resistor R35, a resistor R34, and a capacitor C33. The model of the comparison chip U2 is LM311. One end of the resistor R35 and one end of the capacitor C33 are connected to the first end of the comparison chip U2, respectively. The other end of the resistor R35 is connected to the output end of the operational amplification chip U3. The other end of the capacitor C33 is grounded. The other end of the resistor R38 and one end of the resistor R39 are connected to the second end of the comparison chip U2, respectively. The voltage end of the comparison chip U2 and one end of the resistor R34 are connected together and receive a 5V voltage. The output end of the comparison chip U2 is connected to the other end of the resistor R34.

[0087] As shown in the figure, Figure 10 the trigger module 104 includes a trigger chip U1, a resistor R32, a capacitor C31, and a capacitor C32. The model of the trigger chip U1 can be 74LS74. One end of the resistor R32 is connected to pin 1 of the trigger chip U1. The other end of the resistor R32, one end of the capacitor C31, one end of the capacitor C32, and pin 4 of the trigger chip U1 are connected together and receive a 5V voltage. The other end of the capacitor C31 is grounded. The other end of the capacitor C32 is grounded. Pin 2 of the trigger chip U1 is connected to the output end of the comparison chip U2. Pin 3 of the trigger chip U1 outputs an SD signal.

[0088] As shown in the figure, Figure 11As shown, the control module 105 includes a control chip LM324, a resistor R10, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor R21, a resistor R22, a resistor R23, a resistor R25, a resistor R27, a capacitor C7, a capacitor C8, a triode Q3, one end of the resistor R14 and one end of the resistor R16 are respectively connected to pin 1 of the control chip LM324, the other end of the resistor R16 and one end of the resistor R18 are commonly connected to receive the SW signal, one end of the resistor R15 and one end of the resistor R19 are respectively connected to pin 2 of the control chip LM324, the other end of the resistor R15 is connected to a 5V voltage, the other end of the resistor R19 and one end of the resistor R20 are commonly connected to ground, pin 3 of the control chip receives the SD signal, pin 4 of the control chip LM324 receives a 5V voltage, the other end of the resistor R14 and the other end of the resistor R20 are respectively connected to pin 5 of the control chip LM324, one end of the resistor R23 is connected to pin 6 of the control chip LM324, the other end of the resistor R23 is connected to one end of the resistor R22, one end of the resistor R25 is connected to pin 7 of the control chip LM324, the other end of the resistor R25 is connected to the anode of the light emitting diode G1, the cathode of the light emitting diode G1 is grounded, one end of the resistor R27 is connected to pin 8 of the control chip LM324, the other end of the resistor R27 is connected to the anode of the light emitting diode G2, the cathode of the light emitting diode G2 is grounded, the other end of the resistor R22 and one end of the resistor R21 are respectively connected to pin 9 of the control chip LM324, the other end of the resistor R18 and one end of the capacitor C8 are respectively connected to pin 10 of the control chip LM324, pin 11 of the control chip LM324 is commonly connected to ground with the other end of the resistor R21, the other end of the capacitor C8, the other end of the resistor R11 and one end of the capacitor C7, pin 12 of the control chip LM324 is respectively connected to one end of the resistor R17, one end of the capacitor C7 and the anode of the diode D5, one end of the resistor R12 is connected to the cathode of the diode D5, the other end of the resistor R12 is connected to the other end of the resistor R17, pin 13 of the control chip LM324 is respectively connected to one end of the resistor R10 and one end of the resistor R11, the other end of the resistor R10 receives a 5V voltage, pin 14 of the control chip LM324 is connected to one end of the resistor R13, the other end of the resistor R13 is connected to the base of the triode Q3, the collector of the triode Q3 outputs the MCU signal, and the emitter of the triode Q3 is grounded.

[0089] The working process of the circuit structure provided by the embodiment is as follows:

[0090] As Figure 10As shown, the current output from the power supply circuit is converted into a voltage signal after passing through the operational amplifier U3 differential amplifier circuit. The latter is connected to the input terminal of the comparator LM311. The comparator LM311 determines whether there is a short circuit. If the input voltage signal is greater than the comparator threshold, the comparator LM311 outputs a high-level short-circuit trigger signal, which is connected to the clock input terminal of the CP1 pin of the subsequent flip-flop chip 74LS74.

[0091] When the S1 pin of the 74LS74 flip-flop chip is set low, the SD signal at the non-inverting output of the Q1 pin will be set high, and the D1 pin of the 74LS74 flip-flop chip will...

[0092] —The input terminal, the S1 pin set terminal, and the Q1 inverted output terminal are all at low level.

[0093] like Figure 8 As shown, the SD signal output from pin Q1 of the 74LS74 trigger chip is connected to pin 11 of the IR2110 driver chip. When a short circuit is triggered, the high level of the SD signal will trigger the IR2110 driver chip's PWM control enable, that is, the PWM signal output from pin 7 of the IR2110 driver chip will become low, thereby turning off the MOSFET Q1. Figure 9 As shown, the SD signal is also connected to resistor R7 to control the on / off state of transistor Q2; when the SD signal is high, transistor Q2 will conduct, and the JDQ control signal of normally closed relay K1 will be low after being grounded. The normally closed contact of relay K1 will switch to its normally open contact, thus cutting off the current to the entire circuit. Figure 10 The operational amplifier U3 in the circuit did not receive an overcurrent signal, but because the 74LS74 flip-flop chip did not have a high-level clock and clear terminal valid signal input, the high-level state of the SD signal at the non-inverting output terminal of the Q1 pin of the 74LS74 flip-flop chip would not change, and it would perform continuous protection function when the short circuit continued.

[0094] like Figure 7 and Figure 11As shown, after short circuit, the normally open contact SW of relay K1 is connected to GND through output terminal P2, thus, the normally open contact SW of relay K1 connected to the non-inverting input terminal of Pin10 of control chip LM324 is at low level 0V, the non-inverting amplifier circuit composed of Pin8, Pin9 and Pin10 of control chip LM324 and the peripheral circuit, the output of Pin8 is at low level 0V, the output of the inverter composed of Pin5, Pin6 and Pin7 is at high level 5V. Thus, the green LED lamp G2 is off, and the red LED lamp G1 is on. Pin12 of control chip LM324 is clamped to low level 0V through diode D1, thus, the output Pin14 of the comparator composed of Pin12, Pin13 and Pin14 of control chip LM324 is at low level 0V, causing triode Q3 to be cut off, and the collector signal of triode Q3 is at high level pulled up by resistor R2. When the short circuit is removed, the normally open contact SW of relay K1 is not at 0V, thus, the above logic is reversed, the green LED lamp G2 is on, the red LED lamp G1 is off, and triode Q3 is turned on, and the MCU control signal output from the collector of triode Q3 is at low level 0V. At this time, the clear end Pin1 of flip-flop chip 74LS74 is at active level 0V, and the SD signal output from the non-inverting output end Pin3 of flip-flop chip 74LS74 is at low level 0V, so that the circuit returns to the normal working state.

[0095] Embodiment Two

[0096] The embodiment two provides a DC switching power supply, which comprises the short circuit protection circuit provided in the embodiment one and an input power supply 20. Figure 12 As shown, the input power supply 20 is connected to one end of the switching module 101, and the input power supply 20 inputs DC power to the switching module 101.

[0097] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A short-circuit protection circuit for a direct current switching power supply, characterized by comprising: The short-circuit protection circuit comprises: a switch module, one end of which is connected to an input power supply; a protection module, one end of which is connected to the other end of the switch module to form a power supply circuit with the switch module; a short-circuit detection module, the detection end of which is connected to the output end of the power supply circuit to output a short-circuit trigger signal when the power supply circuit is short-circuited; a trigger module, the input end of which is connected to the output end of the short-circuit detection module, and the output end of which is connected to the control end of the protection module, and the trigger module outputs an open control signal to the protection module when the trigger module receives the short-circuit trigger signal; a control module, the input end of which is connected to the other end of the protection module, and the output end of which is connected to the control end of the trigger module, and the control module outputs a reset signal to the trigger module when the control module receives a short-circuit removal signal of the power supply circuit from the protection module, so that the trigger module outputs a conductive control signal to the protection module.

2. The short circuit protection circuit of claim 1, wherein The protection module comprises: a relay, the normally closed contact of which is one end of the protection module, the normally closed contact of the relay is connected to the other end of the switch module, and the normally open contact of the relay is the other end of the protection module; when the power supply circuit is short-circuited, the voltage of the normally open contact is 0; when the short circuit of the power supply circuit is removed, the voltage of the normally open contact is not 0.

3. The short circuit protection circuit of claim 1, wherein The short-circuit detection module comprises: an operational amplifier unit, the input end of which is connected to the power supply circuit to collect the current in the power supply circuit and convert the collected current into a collected voltage; a comparison unit, the first input end of which is connected to the output end of the operational amplifier unit, and the second input end of which receives a preset voltage to output a short-circuit trigger signal when the collected voltage is greater than the preset voltage.

4. The short circuit protection circuit of claim 1, wherein The control module comprises a control chip and a first switch unit, the input end of the control chip is the input end of the control module, the input end of the control chip is connected to the other end of the protection module, the first output end of the control chip is connected to the control end of the first switch unit, one end of the first switch unit is connected to the control end of the trigger module, and the other end of the first switch unit is grounded.

5. The short circuit protection circuit of claim 4, wherein, The control module is also connected to the output end of the trigger module, and the control module further comprises a first light-emitting diode and a second light-emitting diode, the second output end of the control chip is connected to the anode of the first light-emitting diode, the third output end of the control chip is connected to the anode of the second light-emitting diode, and the cathode of the first light-emitting diode and the cathode of the second light-emitting diode are both grounded.

6. The short circuit protection circuit of claim 1, wherein, The short-circuit protection circuit further comprises: a second switch unit, the control end of the second switch unit is connected to the output end of the trigger module, one end of the second switch unit is connected to the control end of the protection module, and the other end of the second switch unit is grounded.

7. The short circuit protection circuit of claim 1, wherein, The short-circuit protection circuit further comprises: a driving module, the input end of which is connected to the output end of the trigger module, and the output end of which is connected to the control end of the switch module to control the switch module to be open when the open control signal is received and to be conductive when the conductive control signal is received.

8. The short circuit protection circuit of claim 3, wherein, The operation amplification unit comprises an operation amplifier U3, a resistor R31, a resistor R33, a resistor R36, a resistor R37, a resistor R38, a resistor R39 and a capacitor C34, one end of the resistor R33 is a first input end of the operation amplification unit, one end of the resistor R36 is a second input end of the operation amplification unit, the other end of the resistor R33 is connected with one end of the resistor R31, one end of the capacitor C34 and the inverting input end of the operation amplifier U3 respectively, the other end of the resistor R36 is connected with one end of the resistor R37, the other end of the capacitor C34 and the non-inverting input end of the operation amplifier U3 respectively, the voltage end of the operation amplifier U3 receives a first voltage, the ground end of the operation amplifier U3, the other end of the resistor R37 and one end of the resistor R38 are connected with ground, the other end of the resistor R38 is connected with one end of the resistor R39, the other end of the resistor R39 receives a first voltage, the output end of the operation amplifier U3 and the other end of the resistor R31 are connected as an output end of the operation amplification unit.

9. The short circuit protection circuit of claim 3, wherein, The comparison unit comprises a comparison chip U2, a resistor R35, a resistor R34 and a capacitor C33, one end of the resistor R35 and one end of the capacitor C33 are connected with the first end of the comparison chip U2 respectively, the other end of the resistor R35 is a first input end of the comparison unit, the other end of the capacitor C33 is grounded, the other end of the resistor R38 and one end of the resistor R39 are connected with the second end of the comparison chip U2 respectively, the voltage end of the comparison chip U2 and one end of the resistor R34 are connected and then receive a first voltage, the output end of the comparison chip U2 and the other end of the resistor R34 are connected as an output end of the comparison unit.

10. A direct current switching power supply, characterized by The short-circuit protection circuit and the input power source are connected with one end of the switch module. The short-circuit protection circuit and the input power source are connected with one end of the switch module.

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