Backflow prevention circuits and power supply equipment

Abstract

This application provides an anti-backflow circuit and power supply device. The anti-backflow circuit includes: a sampling module, the input terminal of which is coupled to a power supply for acquiring the real-time current value of the power supply and outputting a voltage signal; a comparison module for outputting a comparison signal based on the voltage signal; a control module for outputting a control signal based on the voltage signal; a drive module; and a switching module, the control terminal of which is coupled to the output terminal of the drive module, a first terminal of which is coupled to the second output terminal of the sampling module, and a second terminal of which is coupled to a load. The drive module outputs a drive signal to the switching module based on the comparison signal and / or the control signal to control the on / off state of the switching module. Through the above method, by utilizing the comparison module and the control module to detect backflow current in the power supply based on the real-time output current, the switching module is promptly disconnected, controlling the backflow current within a suitable range and ensuring the safe operation of the power supply.

Description

Technical Field

[0001] This application relates primarily to the field of power supply technology, and in particular to backflow prevention circuits and power supply equipment. Background Technology

[0002] In switching power supplies, backflow prevention circuits are used to prevent current from flowing back into the power supply, ensuring system stability and safety. Backflow current mainly occurs in two situations: external overvoltage and internal short circuit. External overvoltage mainly manifests as overvoltage in other power supplies during parallel operation, causing current to flow back into this power supply. Internal short circuit mainly manifests as a short circuit within the power supply during parallel operation, allowing current from other power supplies to flow back into it.

[0003] Currently, the reverse current protection circuit for MOSFETs determines whether the MOSFET is turned on by detecting the voltage drop across its drain (DS) terminals. When the forward voltage drop exceeds the turn-on threshold voltage, the MOSFET turns on; when the reverse voltage drop falls below the fault threshold voltage, the MOSFET turns off. However, Rds(on) is very small, meaning the MOSFET only turns off when a reverse current of tens of amps occurs. If the voltage drop detection across the MOSFET's DS terminals is insensitive, and the MOSFET fails to turn off in time, simultaneous overvoltage and short circuits can occur both internally and externally. The voltage drop across the MOSFET's DS terminals will then be even less likely to reach the required reverse voltage drop for turn-off. This can also drain the output power of other power supplies, affecting the operation of the powered system. Furthermore, the voltage drop detection across the MOSFET's DS terminals requires appropriate resistors and capacitors, making the debugging process time-consuming. Utility Model Content

[0004] The main purpose of this application is to provide an anti-backflow circuit and power supply equipment to solve the problem of backflow current when the power supply equipment is subjected to internal or external abnormalities. By detecting the output current of the power supply, the backflow current is controlled within a suitable range to achieve the anti-backflow function and protect the power supply safety.

[0005] To address the aforementioned issues, this application provides an anti-backflow circuit and a power supply device. The anti-backflow circuit includes: a sampling module, the input of which is coupled to a power supply for acquiring real-time current values ​​and outputting a voltage signal; a comparison module, the input of which is coupled to a first output of the sampling module for outputting a comparison signal based on the voltage signal; a control module, the input of which is coupled to the first output of the sampling module and the output of which is coupled to the output of the comparison module for outputting a control signal based on the voltage signal; a drive module, the input of which is coupled to the output of the comparison module; and a switch module, the control terminal of which is coupled to the output of the drive module, the first terminal of which is coupled to a second output of the sampling module, and the second terminal of which is coupled to a load. The drive module outputs a drive signal to the switch module based on the comparison signal and / or the control signal to control the on / off state of the switch module.

[0006] In one embodiment, the comparison module includes: an amplification unit, the input of which is coupled to a first output of the sampling module; a comparison unit, the first input of which is coupled to the output of the amplification unit, and the second input of which is grounded; and a hysteresis unit, the input of which is coupled to the output of the comparison unit, and the output of which is coupled to the first input of the comparison unit. The comparison unit is used to output a comparison signal based on a voltage signal and a preset threshold current, and the hysteresis unit sets an on threshold and an off threshold to stabilize the output of the comparison signal.

[0007] In one embodiment, the amplification unit includes: a first resistor, a first end of which is coupled to a first output terminal of the sampling module; a second resistor, a first end of which is coupled to a second output terminal of the sampling module; a third resistor, a first end of which is coupled to a second end of the first resistor, and the second end of the third resistor is grounded; a fourth resistor, a first end of which is coupled to a second end of the second resistor, and the second end of the fourth resistor is coupled to a first input terminal of the comparison unit; and an amplifier, a first input terminal of which is coupled to a second end of the first resistor, a second end of which is coupled to a second end of the second resistor, and an output terminal of which is coupled to the first input terminal of the comparison unit.

[0008] In one embodiment, the comparison unit includes a voltage divider unit and a comparator; the voltage divider unit includes: a fifth resistor, the first end of which is coupled to the output of the amplification unit; a sixth resistor, the first end of which is coupled to the second end of the fifth resistor, and the second end of the sixth resistor is grounded; and a comparator, the first input of which is coupled to the second end of the fifth resistor, the second input of which is grounded, and the output of which is coupled to the input of the driving module.

[0009] In one embodiment, the hysteresis unit includes: a seventh resistor, the first end of which is coupled to the output terminal of the comparator unit; and a first diode, the anode of which is coupled to the second end of the seventh resistor, and the cathode of which is coupled to the first input terminal of the comparator unit.

[0010] In one embodiment, the control module includes: a control chip, a first terminal of which is coupled to a first output terminal of the sampling module; a voltage source, a first terminal of which is coupled to a second terminal of the control chip, and the second terminal of the voltage source is grounded; an eighth resistor, a first terminal of which is coupled to the second terminal of the voltage source; a ninth resistor, a first terminal of which is coupled to the second terminal of the eighth resistor, and the second terminal of the ninth resistor is grounded; a first transistor, a control terminal of which is coupled to the second terminal of the eighth resistor, and the first terminal of the first transistor is grounded; and a second diode, the anode of which is coupled to the second terminal of the first transistor, and the cathode of which is coupled to the output terminal of the comparison module; wherein, the control module outputs a control signal to the drive module according to the voltage signal output by the sampling module and / or the command signal output by the control chip.

[0011] In one embodiment, the driving module includes: a second transistor, the control terminal of which is coupled to the output terminal of the comparator module; a tenth resistor, the first terminal of which is coupled to the first terminal of the second transistor, and the second terminal of which is coupled to the control terminal of the switching module; a third transistor, the control terminal of which is coupled to the output terminal of the comparator module, the first terminal of which is coupled to the second terminal of the second transistor, and the second terminal of which is coupled to the first terminal of the switching module.

[0012] In one embodiment, the backflow prevention circuit further includes: a protection module, a first end of which is coupled to a first output end of the drive module, a second end of which is coupled to a second output end of the drive module and a first end of the switch module, and a third end of which is coupled to a second end of the switch module.

[0013] In one embodiment, the protection module includes: an eleventh resistor, the first end of which is coupled to the first output terminal of the drive module, and the second end of which is coupled to the second output terminal of the drive module and the first terminal of the switch module; a third diode, the cathode of which is coupled to the first end of the eleventh resistor; and a fourth diode, the anode of which is coupled to the anode of the third diode, and the cathode of which is coupled to the second terminal of the switch module.

[0014] To address the aforementioned issues, this application also provides a power supply device comprising: a power supply; and an anti-backflow circuit coupled to the power supply, wherein the anti-backflow circuit is the anti-backflow circuit described in any of the above embodiments.

[0015] This application provides an anti-backflow circuit and power supply device. A sampling module samples the power supply output current, and based on the sampled current information, a comparison module and a control module output comparison and control signals. A drive module controls the on / off state of a switching module based on the input comparison and / or control signals. This dual-signal drive enhances the driving force and accelerates the disconnection control of the switching module. Furthermore, based on the real-time output current value of the power supply, it determines whether there is an abnormal situation of backflow current in the power supply. The switching module promptly cuts off the circuit, controlling the magnitude of the backflow current within an appropriate range to ensure the safe operation of the power supply. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0017] Figure 1This is a schematic diagram of the structure of the first embodiment of the anti-backflow circuit provided in this application;

[0018] Figure 2 This is a schematic diagram of the structure of an embodiment of the comparison module provided in this application;

[0019] Figure 3 This is a schematic diagram of the structure of an embodiment of the enlargement unit provided in this application;

[0020] Figure 4 This is a schematic diagram of the structure of an embodiment of the comparison unit provided in this application;

[0021] Figure 5 This is a schematic diagram of the structure of an embodiment of the hysteresis unit provided in this application;

[0022] Figure 6 This is a schematic diagram of the structure of an embodiment of the control module provided in this application;

[0023] Figure 7 This is a schematic diagram of the structure of an embodiment of the driver module provided in this application;

[0024] Figure 8 This is a schematic diagram of the structure of the second embodiment of the anti-backflow circuit provided in this application;

[0025] Figure 9 This is a schematic diagram of the structure of an embodiment of the protection module provided in this application;

[0026] Figure 10 This is a schematic diagram of the third embodiment of the anti-backflow circuit provided in this application;

[0027] Figure 11 This is a flowchart illustrating the steps of an embodiment of the backflow prevention control method provided in this application;

[0028] Figure 12 This is a waveform diagram of an embodiment of the anti-backflow circuit provided in this application;

[0029] Figure 13 This is a schematic diagram of an embodiment of the power supply device provided in this application.

[0030] Icon labels:

[0031] 100. Anti-backflow circuit; 10. Sampling module; 20. Comparison module; 21. Amplification unit; 210. Amplifier; 22. Comparison unit; 220. Voltage divider unit; 221. Comparator; 23. Hysteresis unit; 30. Control module; 31. Control chip; 32. Voltage source; 40. Drive module; 50. Switching module; 60. Protection module; 70. Voltage divider module; 400. Power supply equipment; 410. Power supply. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] The terms "first," "second," etc., used in this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0034] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0035] See Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of the first embodiment of the anti-backflow circuit provided in this application; the anti-backflow circuit 100 includes: a sampling module 10, a comparison module 20, a control module 30, a drive module 40, and a switch module 50.

[0036] Specifically, the input terminal of the sampling module 10 is coupled to the power supply to collect the real-time current value of the power supply and output a voltage signal; the input terminal of the comparison module 20 is coupled to the first output terminal of the sampling module 10 to output a comparison signal based on the voltage signal; the input terminal of the control module 30 is coupled to the first output terminal of the sampling module 10, and the output terminal of the control module 30 is coupled to the output terminal of the comparison module 20 to output a control signal based on the voltage signal; the input terminal of the drive module 40 is coupled to the output terminal of the comparison module 20; the control terminal of the switch module 50 is coupled to the output terminal of the drive module 40, the first terminal of the switch module 50 is coupled to the second output terminal of the sampling module 10, and the second terminal of the switch module 50 is used to couple to the load; wherein, the drive module 40 is used to output a drive signal to the switch module 50 based on the comparison signal and / or the control signal to control the on / off state of the switch module 50.

[0037] Understandably, in one embodiment, the switching module 50 is an OR-ing transistor (MOS transistor). The comparison module 20 performs hardware comparison and determination on the sampled output current value to output a hardware control signal; the control module 30 receives control commands from the device terminal or performs software comparison and determination on the sampled output current value to output a software control signal. The drive module 40 drives the switching module 50 to switch its on / off state based on the input software and hardware control signals. This dual hardware and software control improves the driving force, accelerates the disconnection of the switching module 50 when reverse current is detected, effectively reduces the voltage stress on the switching module 50, and controls the reverse current within a suitable range by detecting the power supply output current, thus achieving reverse current prevention and protecting power supply safety.

[0038] In one embodiment, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the structure of an embodiment of the comparison module provided in this application; the comparison module 20 includes: an amplification unit 21, a comparison unit 22, and a hysteresis unit 23.

[0039] Specifically, the input terminal of the amplification unit 21 is coupled to the first output terminal of the sampling module 10; the first input terminal of the comparison unit 22 is coupled to the output terminal of the amplification unit 21, and the second input terminal of the comparison unit 22 is grounded; the input terminal of the hysteresis unit 23 is coupled to the output terminal of the comparison unit 22, and the output terminal of the hysteresis unit 23 is coupled to the first input terminal of the comparison unit 22; wherein, the comparison unit 22 is used to output a comparison signal based on the voltage signal and the preset threshold current, and the hysteresis unit 23 sets the turn-on threshold and the turn-off threshold to stabilize the output of the comparison signal.

[0040] Understandably, the comparison unit 22 compares the real-time current value with the preset current threshold. When the real-time current value is greater than the preset turn-on current threshold, it outputs a high level, and when the real-time current is lower than the preset turn-off current threshold, it outputs a low level. The preset turn-on current threshold is greater than the preset turn-off current threshold. The above process can be implemented by the hysteresis unit 23.

[0041] In one embodiment, such as Figure 3 As shown, Figure 3This is a schematic diagram of an embodiment of the amplification unit provided in this application; the amplification unit 21 includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and an amplifier 210; wherein, the first end of the first resistor R1 is coupled to the first output terminal of the sampling module 10; the first end of the second resistor R2 is coupled to the second output terminal of the sampling module 10; the first end of the third resistor R3 is coupled to the second end of the first resistor R1, and the second end of the third resistor R3 is grounded; the first end of the fourth resistor R4 is coupled to the second end of the second resistor R2, and the second end of the fourth resistor R4 is coupled to the first input terminal of the comparison unit 22; the first input terminal of the amplifier 210 is coupled to the second end of the first resistor R1, the second end of the amplifier 210 is coupled to the second end of the second resistor R2, and the output terminal of the amplifier 210 is coupled to the first input terminal of the comparison unit 22.

[0042] The amplification unit 21 amplifies the power output current and voltage sampled by the sampling module 10, and then transmits the amplified signal to the comparison unit 22 for subsequent comparison and judgment.

[0043] In one embodiment, such as Figure 4 As shown, Figure 4 This is a schematic diagram of an embodiment of the comparison unit provided in this application; the comparison unit 22 includes a voltage divider unit 220 and a comparator 221; wherein, the voltage divider unit 220 includes: a fifth resistor R5 and a sixth resistor R6; specifically, the first end of the fifth resistor R5 is coupled to the output end of the amplification unit 21; the first end of the sixth resistor R6 is coupled to the second end of the fifth resistor R5, and the second end of the sixth resistor R6 is grounded; the comparator 221 has its first input end coupled to the second end of the fifth resistor R5, its second input end grounded, and its output end coupled to the input end of the drive module 40.

[0044] The comparison unit 22 compares the real-time sampled output current value with a set current threshold, and outputs different control signals based on different comparison results. For example, it compares the real-time current value with a preset current threshold. When the real-time current value is greater than the preset turn-on current threshold, it outputs a high level; when the real-time current value is less than the preset turn-off current threshold, it outputs a low level. The preset turn-on current threshold is greater than the preset turn-off current threshold.

[0045] In one embodiment, such as Figure 5 As shown, Figure 5 This is a schematic diagram of an embodiment of the hysteresis unit provided in this application; the hysteresis unit 23 includes: a seventh resistor R7 and a first diode D1, the first end of the seventh resistor R7 is coupled to the output end of the comparator unit 22; the anode of the first diode D1 is coupled to the second end of the seventh resistor R7, and the cathode of the first diode D1 is coupled to the first input end of the comparator unit 22.

[0046] The hysteresis unit 23 can prevent frequent output signal jumps caused by small fluctuations in the input signal by setting two different thresholds (upper threshold and lower threshold). This characteristic allows the hysteresis circuit to effectively suppress noise and interference in the input signal, thereby improving system stability. When the input signal exceeds the upper threshold, the output signal switches to a high level; when the input signal is below the lower threshold, the output signal switches to a low level. Between the two thresholds, the output signal remains unchanged; this characteristic is called hysteresis.

[0047] In one embodiment, such as Figure 6 As shown, Figure 6 This is a schematic diagram of the structure of an embodiment of the control module provided in this application; the control module 30 includes: a control chip 31, a voltage source 32, an eighth resistor R8, a ninth resistor R9, a first transistor Q1, and a second diode D2.

[0048] In this configuration, the first terminal of the control chip 31 is coupled to the first output terminal of the sampling module 10; the first terminal of the voltage source 32 is coupled to the second terminal of the control chip 31, and the second terminal of the voltage source 32 is grounded; the first terminal of the eighth resistor R8 is coupled to the second terminal of the voltage source 32; the first terminal of the ninth resistor R9 is coupled to the second terminal of the eighth resistor R8, and the second terminal of the ninth resistor R9 is grounded; the control terminal of the first transistor Q1 is coupled to the second terminal of the eighth resistor R8, and the first terminal of the first transistor Q1 is grounded; the anode of the second diode D2 is coupled to the second terminal of the first transistor Q1, and the cathode of the second diode D2 is coupled to the output terminal of the comparison module 20; wherein, the control module 30 outputs a control signal to the drive module 40 according to the voltage signal output by the sampling module 10 and / or the command signal output by the control chip 31.

[0049] Understandably, in one embodiment, the control chip 31 can directly receive instruction signals from the device terminal and output corresponding control signals to directly control the on / off state of the switch module 50. In other embodiments, the control chip 31 can receive the real-time output current value of the sampling module 10, judge it according to the current threshold set by software, and output corresponding software control signals. Based on the above, the hardware control signal output by the comparison module 20 through hardware judgment can be combined to enhance the driving force of the drive module 40 and realize dual-threshold control. In one embodiment, the control chip 31 is a microcontroller unit (MCU).

[0050] In one embodiment, such as Figure 7 As shown, Figure 7 This is a schematic diagram of a driving module according to an embodiment of the present application; the driving module 40 includes: a second transistor Q2, a tenth resistor R10 and a third transistor Q3.

[0051] In this configuration, the control terminal of the second transistor Q2 is coupled to the output terminal of the comparator module 20; the first terminal of the tenth resistor R10 is coupled to the first terminal of the second transistor Q2, and the second terminal of the tenth resistor R10 is coupled to the control terminal of the switch module 50; the control terminal of the third transistor Q3 is coupled to the output terminal of the comparator module 20, the first terminal of the third transistor Q3 is coupled to the second terminal of the second transistor Q2, and the second terminal of the third transistor Q3 is coupled to the first terminal of the switch module 50.

[0052] The drive module 40 controls the switching of the switch module 50 through a transistor push-pull circuit.

[0053] In one embodiment, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the structure of the second embodiment of the anti-backflow circuit provided in this application; the anti-backflow circuit 100 further includes: a protection module 60, the first end of the protection module 60 is coupled to the first output end of the drive module 40, the second end of the protection module 60 is coupled to the second output end of the drive module 40 and the first end of the switch module 50, and the third end of the protection module 60 is coupled to the second end of the switch module 50.

[0054] In one embodiment, such as Figure 9 As shown, Figure 9 This is a schematic diagram of the structure of an embodiment of the protection module provided in this application; the protection module 60 includes: an eleventh resistor R11, the first end of which is coupled to the first output terminal of the drive module 40, the second end of which is coupled to the second output terminal of the drive module 40 and the first terminal of the switch module 50; a third diode D3, the cathode of which is coupled to the first end of the eleventh resistor R11; and a fourth diode D4, the anode of which is coupled to the anode of the third diode D3, and the cathode of which is coupled to the second terminal of the switch module 50.

[0055] Through the above embodiments, the switching module 50 is protected in a conventional way to prevent VGS from exceeding the specification using a Zener diode. That is, once the signal output by the control chip 31 is detected to be high, the drive signal is immediately pulled low to turn off the switching module 50.

[0056] Referring to the solutions in the above embodiments, see Figure 10 As shown, Figure 10 This is a schematic diagram of the structure of the third embodiment of the anti-backflow circuit provided in this application; specifically, as shown... Figure 10 As shown, the anti-backflow circuit 100 also includes a voltage divider module 70, which includes a twelfth resistor R12 and a thirteenth resistor R13.

[0057] Specifically, the first end of the twelfth resistor R12 is coupled to the output of the comparator module 20, and the second end of the twelfth resistor R12 is coupled to the output of the control module 30; the first end of the thirteenth resistor R13 is coupled to the second end of the twelfth resistor R12, and the second end of the thirteenth resistor R13 is coupled to the input of the drive module 40. This allows the voltage divider module 70 to adjust the different voltage requirements of the various modules.

[0058] To address the aforementioned problems, this application also provides an anti-backflow control method, which is applied to an anti-backflow circuit 100, as described in any of the embodiments above. Figure 11 and Figure 12 As shown, Figure 11 This is a flowchart illustrating the steps of an embodiment of the backflow prevention control method provided in this application; Figure 12 This is a waveform diagram of an embodiment of the anti-backflow circuit provided in this application; the method includes the following steps:

[0059] Step S10: Collect the output current of the power supply.

[0060] The sampling module 10 samples the output current of the power supply in real time, so that the sampled current value can be used for logical judgment in the subsequent process to control the on / off state of the switching module 50.

[0061] Step S20: Output the first control signal based on the output current and the set software threshold current.

[0062] Understandably, the output current is first determined by the control module 30, and the first control signal is output accordingly.

[0063] Step S30: In response to the first control signal indicating that the control switch module 50 is closed, a second control signal is sent to the switch module 50 to close the switch module 50.

[0064] In other embodiments, if the software control unit responds to the closing of the control switch module 50 from other control signals, it directly sends a second control signal to the switch module 50 to close the switch module 50. That is, in this case, the switch module 50 in the anti-backflow circuit 100 is directly closed and no further hardware control processing is performed.

[0065] Step S40: In response to the first control signal indicating that the control switch module 50 is turned on, a third control signal is output to the switch module 50 according to the output current and the set hardware threshold current, so as to control the switch module 50 to be in the on state, the off state, or maintain the state of the previous cycle.

[0066] Understandably, in the above scheme, the software threshold current is the threshold current threshold preset by the control module 30; the hardware threshold current is the threshold current threshold preset by the comparison module 20, so as to control the on / off state of the switch module 50 by threshold determination.

[0067] In this design, a dual-threshold shutdown mechanism is implemented by combining software and hardware control. During the software-driven process, hardware control can be triggered simultaneously to further control the shutdown process and accelerate the shutdown process.

[0068] To address the aforementioned problems, this application also provides a power supply device 400, such as... Figure 13 As shown, Figure 13 This is a schematic diagram of a power supply device 400 according to an embodiment of the present application; the power supply device 400 includes: a power supply 410; and an anti-backflow circuit 100, which is coupled to the power supply 410. The anti-backflow circuit 100 is the anti-backflow circuit 100 described in any of the above embodiments.

[0069] This application provides an anti-backflow circuit and power supply device. A sampling module samples the power supply output current, and based on the sampled current information, a comparison module and a control module output comparison and control signals. A drive module controls the on / off state of a switching module based on the input comparison and / or control signals. This dual-signal drive enhances the driving force and accelerates the disconnection control of the switching module. Furthermore, based on the real-time output current value of the power supply, it determines whether there is an abnormal situation of backflow current in the power supply. The switching module promptly cuts off the circuit, controlling the magnitude of the backflow current within an appropriate range to ensure the safe operation of the power supply.

[0070] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A backfeed prevention circuit, comprising: The backflow prevention circuit includes: A sampling module, the input of which is coupled to a power supply, is used to acquire the real-time current value of the power supply and output a voltage signal; A comparison module, wherein the input terminal of the comparison module is coupled to the first output terminal of the sampling module, and is used to output a comparison signal according to the voltage signal; A control module, wherein the input terminal of the control module is coupled to the first output terminal of the sampling module, and the output terminal of the control module is coupled to the output terminal of the comparison module, and is used to output a control signal according to the voltage signal; A driving module, wherein the input terminal of the driving module is coupled to the output terminal of the comparison module; A switching module, wherein the control terminal of the switching module is coupled to the output terminal of the drive module, the first terminal of the switching module is coupled to the second output terminal of the sampling module, and the second terminal of the switching module is used to couple to the load; The driving module is used to output a driving signal to the switching module according to the comparison signal and / or the control signal, so as to control the on / off state of the switching module.

2. The backflow prevention circuit of claim 1, wherein, The comparison module includes: An amplification unit, wherein the input terminal of the amplification unit is coupled to the first output terminal of the sampling module; The comparison unit has a first input terminal coupled to the output terminal of the amplification unit, and a second input terminal grounded. A hysteresis unit, wherein the input terminal of the hysteresis unit is coupled to the output terminal of the comparison unit, and the output terminal of the hysteresis unit is coupled to the first input terminal of the comparison unit; The comparison unit is used to output the comparison signal based on the voltage signal and the preset threshold current, and the hysteresis unit sets the turn-on threshold and the turn-off threshold to stabilize the output of the comparison signal.

3. The anti-backflow circuit according to claim 2, characterized in that, The amplification unit includes: A first resistor, the first end of which is coupled to the first output terminal of the sampling module; The second resistor has its first end coupled to the second output terminal of the sampling module. A third resistor, wherein the first end of the third resistor is coupled to the second end of the first resistor, and the second end of the third resistor is grounded; A fourth resistor, the first end of which is coupled to the second end of the second resistor, and the second end of the fourth resistor is coupled to the first input terminal of the comparison unit; An amplifier, wherein the first input terminal of the amplifier is coupled to the second terminal of the first resistor, the second terminal of the amplifier is coupled to the second terminal of the second resistor, and the output terminal of the amplifier is coupled to the first input terminal of the comparator unit.

4. The anti-backflow circuit according to claim 2, characterized in that, The comparison unit includes a voltage divider unit and a comparator; The voltage divider unit includes: The fifth resistor, the first end of which is coupled to the output terminal of the amplification unit; A sixth resistor, the first end of which is coupled to the second end of the fifth resistor, and the second end of the sixth resistor is grounded; The comparator has its first input terminal coupled to the second terminal of the fifth resistor, its second input terminal grounded, and its output terminal coupled to the input terminal of the drive module.

5. The anti-backflow circuit according to claim 2, characterized in that, The hysteresis unit includes: The seventh resistor, the first end of which is coupled to the output terminal of the comparator unit; A first diode, the anode of which is coupled to the second terminal of the seventh resistor, and the cathode of which is coupled to the first input terminal of the comparator unit.

6. The anti-backflow circuit according to claim 1, characterized in that, The control module includes: A control chip, wherein a first terminal of the control chip is coupled to a first output terminal of the sampling module; A voltage source, wherein a first terminal of the voltage source is coupled to a second terminal of the control chip, and the second terminal of the voltage source is grounded; The eighth resistor, the first end of which is coupled to the second end of the voltage source; A ninth resistor, the first end of which is coupled to the second end of the eighth resistor, and the second end of the ninth resistor is grounded; The first transistor has its control terminal coupled to the second terminal of the eighth resistor, and its first terminal is grounded. The second diode has its anode coupled to the second terminal of the first transistor and its cathode coupled to the output terminal of the comparator module. The control module outputs the control signal to the drive module based on the voltage signal output by the sampling module and / or the command signal output by the control chip.

7. The anti-backflow circuit according to claim 1, characterized in that, The driving module includes: The control terminal of the second transistor is coupled to the output terminal of the comparator module; The tenth resistor has its first end coupled to the first end of the second transistor, and its second end coupled to the control terminal of the switching module. The third transistor has its control terminal coupled to the output terminal of the comparator module, its first terminal coupled to the second terminal of the second transistor, and its second terminal coupled to the first terminal of the switch module.

8. The anti-backflow circuit according to claim 1, characterized in that, The backflow prevention circuit also includes: A protection module, wherein a first end of the protection module is coupled to a first output end of the drive module, a second end of the protection module is coupled to a second output end of the drive module and a first end of the switch module, and a third end of the protection module is coupled to a second end of the switch module.

9. The anti-backflow circuit according to claim 8, characterized in that, The protection module includes: The eleventh resistor has its first end coupled to the first output terminal of the drive module, and its second end coupled to the second output terminal of the drive module and the first terminal of the switch module. The third diode, the cathode of which is coupled to the first terminal of the eleventh resistor; A fourth diode, the anode of which is coupled to the anode of the third diode, and the cathode of which is coupled to the second terminal of the switching module.

10. A power supply device, characterized in that, The power supply device includes: power supply; An anti-backflow circuit is coupled to the power supply, and the anti-backflow circuit is the anti-backflow circuit as described in any one of claims 1-9.

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