Short circuit protection circuit and power supply system

Abstract

The utility model relates to the technical field of power supplies, and mainly provides a short circuit protection circuit and a power supply system, the circuit comprises a voltage maintaining module, a voltage dividing module and a comparison module; the comparison module is connected with the voltage maintaining module and the voltage dividing module. The voltage dividing module is used for dividing the output voltage of the working circuit and outputting a first voltage to the comparison module when the working circuit works normally or outputting a second voltage to the comparison module when the working circuit is short-circuited. When the working circuit is normal, the voltage maintaining module stores the output voltage and outputs a third voltage to the comparison module, so that the comparison module outputs a first control signal according to the first voltage and the third voltage to control the working circuit to maintain the working state. And the output of the third voltage is maintained according to the stored voltage during short circuit, so that the comparison module outputs a second control signal to control the working circuit to stop working. On the basis, quick response can be realized through a pure analog circuit when the working circuit is short-circuited, so that the reliability of the power supply is improved.

Description

Technical field

[0001] The utility model relates to the technical field of power supplies, in particular to a short-circuit protection circuit and a power supply system. [Background Technology]

[0002] The continuous development and widespread use of electronic devices have placed higher demands on the stability and safety of power supply systems. Improving power supply reliability is crucial in switching power supply applications. Output voltage short circuits are a common fault condition that switching power supplies may encounter. If protective measures are not taken promptly, a short circuit can cause serious damage to the power supply and connected loads, and even lead to safety accidents.

[0003] There are two main protection methods commonly used in related technologies. One is to sample the internal primary current or voltage for judgment. However, this method can be overly sensitive and can cause false triggering under certain special operating conditions, such as startup, load shedding, and temporary input voltage drops, thereby affecting the normal operation of the power supply. The other is to sample the output current for differential amplification. However, this method needs to be distinguished from current precision sampling. The differential signal is separately obtained from the sampling resistor, amplified, and then compared with the reference. The output of the comparator is used as the short-circuit switching signal. However, this method is more complex and has high requirements for PCB (Printed Circuit Board) routing, which increases the difficulty and cost of design and production.

[0004] Therefore, in order to improve the reliability and stability of the power supply, a short circuit protection circuit must be proposed. [Utility Model Content]

[0005] The embodiments of the present invention provide a short-circuit protection circuit and a power supply system, aiming to solve the technical problems of low power reliability and low stability in related technologies.

[0006] In order to solve the above technical problems, a technical solution adopted by the embodiment of the present utility model is: providing a short-circuit protection circuit, the short-circuit protection circuit including a voltage maintaining module, a voltage dividing module and a comparison module;

[0007] The voltage maintaining module and the voltage dividing module are respectively connected to the input end of the comparison module, the output end of the comparison module is connected to the controller, and the voltage maintaining module and the voltage dividing module are also connected to the working circuit;

[0008] The voltage dividing module is used to divide the output voltage of the working circuit to output a first voltage to the comparison module when the working circuit operates normally; and

[0009] outputting a second voltage to the comparison module when the working circuit is short-circuited;

[0010] The voltage maintaining module is used to divide the output voltage of the working circuit to output a third voltage to the comparison module when the working circuit operates normally; and

[0011] storing the output voltage of the working circuit when the working circuit operates normally, so as to continuously output a third voltage to the comparison module when the working circuit is short-circuited, wherein the third voltage is less than the first voltage and greater than the second voltage;

[0012] The comparison module is configured to output a first control signal to the controller when receiving the first voltage and the third voltage, so that the controller maintains the working state of the working circuit; and

[0013] When the second voltage and the third voltage are received, a second control signal is output to the controller, so that the controller controls the working circuit to stop working.

[0014] Optionally, the voltage maintaining module includes a maintaining unit and a voltage dividing unit;

[0015] The maintaining unit is connected to the voltage dividing unit, the voltage dividing unit is connected to the inverting input terminal of the comparison module, and the maintaining unit is also connected to the working circuit;

[0016] The maintaining unit is used to store the output voltage of the working circuit when the working circuit is operating normally, and transmit the output voltage of the working circuit to the voltage dividing unit; and

[0017] When the working circuit is short-circuited, outputting the stored voltage to the voltage dividing unit;

[0018] The voltage dividing unit is used to divide the voltage output by the maintaining unit to output a third voltage to the inverting input terminal of the comparison module.

[0019] Optionally, the maintaining unit includes a diode D1 and an energy storage capacitor C1;

[0020] The anode of the diode D1 is connected to the working circuit, and the cathode of the diode D1 is connected to the energy storage capacitor C1 and the voltage dividing unit respectively. The energy storage capacitor C1 is also used for grounding.

[0021] Optionally, the voltage dividing unit includes a resistor R1 and a resistor R2;

[0022] The resistor R1 is connected in series with the resistor R2. The resistor R1 is also connected to the cathode of the diode D1 and the inverting input terminal of the comparison module respectively. The resistor R2 is also grounded.

[0023] Optionally, the voltage divider module includes a resistor R3 and a resistor R4;

[0024] The resistor R3 is connected in series with the resistor R4. The resistor R3 is also connected to the working circuit and the non-inverting input terminal of the comparison module respectively. The resistor R4 is also used for grounding.

[0025] Optionally, the comparison module includes a comparator U1 and a signal locking unit;

[0026] The non-inverting input terminal of the comparator U1 is connected to the voltage divider module, the inverting input terminal of the comparator U1 is connected to the voltage maintaining module, the output terminal of the comparator U1 is connected to the controller, and the signal locking unit is connected to the output terminal of the comparator U1 and the non-inverting input terminal of the comparator U1 respectively;

[0027] The comparator U1 is configured to output a first control signal according to the first voltage and the third voltage; and

[0028] outputting a second control signal according to the second voltage and the third voltage;

[0029] The signal locking unit is configured to adjust the voltage division ratio of the voltage division module when the comparator U1 outputs the second control signal, so that the comparator U1 continuously outputs the second control signal.

[0030] Optionally, the signal locking unit includes a resistor R5;

[0031] The resistor R5 is connected to the output terminal of the comparator U1 and the non-inverting input terminal of the comparator U1 respectively.

[0032] Optionally, the comparison module further includes a voltage providing unit;

[0033] The voltage providing unit is connected to the output terminal of the comparator U1, and the voltage providing unit is also used to connect to the battery in the working circuit;

[0034] The voltage providing unit is used to provide an operating voltage to the non-inverting input terminal of the comparator U1 through the signal locking unit when the operating circuit is not operating, so that the comparator U1 outputs a first control signal to the controller.

[0035] Optionally, the voltage providing unit includes a resistor R6;

[0036] The resistor R6 is connected to the signal locking unit and the battery of the working circuit respectively.

[0037] In order to solve the above technical problems, another technical solution adopted by the embodiment of the present invention is to provide a power supply system, which includes:

[0038] Battery;

[0039] Controller;

[0040] operating circuit; and

[0041] Short circuit protection circuit as described above.

[0042] Different from the related art, the present invention provides a short-circuit protection circuit and power supply system. The short-circuit protection circuit includes a voltage maintenance module, a voltage divider module, and a comparison module. The voltage maintenance module and the voltage divider module are respectively connected to the input of the comparison module, and the output of the comparison module is connected to a controller. The voltage maintenance module and the voltage divider module are also connected to the working circuit. The voltage divider module is used to divide the output voltage of the working circuit and output a first voltage to the comparison module when the working circuit is operating normally, and output a second voltage to the comparison module when the working circuit is short-circuited. The voltage maintenance module is mainly used to store the output voltage and output a third voltage to the comparison module when the working circuit is operating normally. In this case, the comparison module receives the first and third voltages. Since the first voltage is greater than the third voltage, the comparison module outputs a first control signal to the controller to maintain the current operating state of the working circuit. When the working circuit is short-circuited, the voltage maintenance module maintains the output of the third voltage to the comparison module based on the stored voltage, causing the comparison module to output a second control signal based on the third voltage greater than the second voltage, thereby stopping the working circuit. Based on this, a pure analog circuit can be used to achieve a fast response when the working circuit is short-circuited, thereby improving the reliability of the power supply.

Brief Description of the Drawings

[0043] One or more embodiments are exemplarily illustrated by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0044] Figure 1 This is a structural block diagram of a power supply system provided by an embodiment of the present utility model;

[0045] Figure 2 This is a structural block diagram of a short-circuit protection circuit provided by an embodiment of the present utility model;

[0046] Figure 3 This is a circuit diagram of a short-circuit protection circuit provided by an embodiment of the utility model. [Specific implementation method]

[0047] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0048] The technical features involved in the various embodiments of the present application described below do not conflict with each other and can be combined with each other.

[0049] When an element is referred to as being “connected to” another element, it can be directly connected to the other element, or one or more intervening elements may be present therebetween.

[0050] The terms "first," "second," and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein. Furthermore, the objects distinguished by "first," "second," and the like are generally of a class, and do not limit the number of objects. For example, the first object may be one or more.

[0051] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art in the field of the present invention. The terms used in this specification are intended only to describe specific embodiments and are not intended to limit the present invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0052] See also Figure 1 , Figure 1 This is a structural block diagram of a power supply system provided by an embodiment of the present utility model. Figure 1 As shown, the power supply system 100 includes a working circuit 10, a controller 20, and a short-circuit protection circuit 30; the short-circuit protection circuit 30 is connected to the working circuit 10 and the controller 20, respectively, and the controller 20 is also connected to the working circuit 10. The short-circuit protection circuit 30 is configured to receive the output voltage of the working circuit 10 in real time while the working circuit 10 is operating, and to determine whether the working circuit 10 is short-circuited based on the output voltage. When the working circuit 10 is short-circuited, the short-circuit protection circuit 30 outputs a short-circuit signal to the controller 20, causing the controller 20 to control the working circuit 10 to stop operating, thereby protecting the power supply system 100 and improving the safety of the power supply system 100.

[0053] In some embodiments, as Figure 1As shown, the power supply system 100 also includes a battery 40, and the battery 40 is connected to the working circuit 10. The working circuit 10 is used to receive and process the output voltage of the battery 40 to output a voltage of a preset amplitude. It should be noted that when the working circuit 10 is short-circuited, the output voltage of the working circuit 10 gradually decreases. At this time, the output voltage received by the short-circuit protection module 30 also gradually decreases, so that it can be determined based on the output voltage that the working circuit 10 has a short-circuit fault. That is, the short-circuit protection module 30 detects the output voltage of the working circuit 10 in real time. When the output voltage is less than a preset threshold, it is considered that the working circuit 10 has a short-circuit fault. At this time, the controller 20 controls the working circuit 10 to stop working, thereby protecting the working circuit 10 and improving the stability of the working circuit 10.

[0054] In some embodiments, see Figure 2 , Figure 2 This is a structural block diagram of a short-circuit protection circuit provided by an embodiment of the present utility model. Figure 2 As shown, the short-circuit protection circuit 30 includes a voltage maintaining module 31, a voltage dividing module 32 and a comparison module 33;

[0055] The voltage maintaining module 31 and the voltage dividing module 32 are both connected to the input end of the comparison module 33 , the output end of the comparison module 33 is connected to the controller 20 , and the voltage maintaining module 31 and the voltage dividing module 32 are also both connected to the working circuit 10 .

[0056] The voltage dividing module 32 is used to divide the output voltage of the working circuit 10 to output a first voltage to the comparison module 33 when the working circuit 10 works normally; and

[0057] outputting a second voltage to the comparison module 33 when the working circuit 10 is short-circuited;

[0058] The voltage maintaining module 32 is used to divide the output voltage of the working circuit 10 so as to output a third voltage to the comparing module 33 when the working circuit 10 is working normally; and

[0059] storing the output voltage of the working circuit 10 when the working circuit 10 is working normally, so as to continuously output a third voltage to the comparison module 33 when the working circuit 10 is short-circuited, wherein the third voltage is less than the first voltage and greater than the second voltage;

[0060] The comparison module 33 is configured to output a first control signal to the controller 20 upon receiving the first voltage and the third voltage, so as to enable the controller 20 to maintain the working state of the working circuit 10; and

[0061] When the second voltage and the third voltage are received, the controller 20 outputs a second control signal to the controller 20 so that the controller 20 controls the working circuit 10 to stop working.

[0062] It should be noted that the voltage maintaining module 32 and the voltage dividing module 31 are both used to divide the output voltage of the working circuit 10. When the working circuit 10 is operating normally, the first voltage divided by the voltage dividing module 31 will be greater than the third voltage divided by the voltage maintaining module 32. At this time, the comparison module 33 will output a first control signal to the controller 20, thereby causing the working circuit 10 to maintain its current operating state. When the working circuit 10 is short-circuited, the output voltage of the working circuit 10 will gradually decrease, and the voltage divided by the voltage dividing module 31 and the voltage maintaining module 32 will also gradually decrease. Since the voltage maintaining module 32 stores the voltage when the working circuit 10 is operating normally, the voltage divided by the voltage maintaining module 32 will still be maintained at the third voltage after the working circuit 10 is short-circuited. At this time, the voltage input from the voltage maintaining module 32 to the comparison module 33 will be greater than the voltage output from the voltage dividing module 31 to the comparison module 33, causing the controller 20 to receive a second control signal, thereby causing the working circuit 10 to stop operating. Based on this, the working circuit 10 can be protected when the working circuit 10 is short-circuited, thereby improving the reliability of the power supply system 100.

[0063] In yet another embodiment, Figure 2 As shown, the voltage maintaining module 32 includes a maintaining unit 321 and a voltage dividing unit 322; the maintaining unit 321 is connected to the voltage dividing unit 322, the voltage dividing unit 322 is connected to the inverting input terminal of the comparison module 33, and the maintaining unit 321 is also connected to the working circuit 10;

[0064] The maintaining unit 321 is used to store the output voltage of the working circuit 10 when the working circuit 10 is working normally, and transmit the output voltage of the working circuit 10 to the voltage dividing unit 322; and

[0065] When the working circuit 10 is short-circuited, the stored voltage is output to the voltage dividing unit 322;

[0066] The voltage dividing unit 322 is used to divide the voltage output by the maintaining unit 321 to output a third voltage to the inverting input terminal of the comparison module 33 .

[0067] Specifically, when the working circuit 10 is operating normally, the maintaining unit 321 receives the output voltage of the working circuit 10 and inputs the output voltage to the voltage dividing unit 322, causing the voltage dividing unit 322 to divide the output voltage. Furthermore, after receiving the output voltage, the voltage dividing unit 322 stores the output voltage. After dividing the output voltage, the voltage dividing unit 322 inputs the divided third voltage to the inverting input terminal of the comparison module 33, causing the comparison module 33 to output a corresponding control signal based on the magnitude of the first and third voltages.

[0068] When the working circuit 10 is short-circuited, the voltage input to the maintaining unit 321 gradually decreases, and the maintaining unit 321 inputs the stored voltage to the voltage dividing unit 322, causing the voltage dividing unit 322 to divide the stored voltage. At this time, the voltage divided by the voltage dividing unit 322 is also the third voltage, and the third voltage is input to the comparison module 33, so that the comparison module 33 outputs a corresponding control signal based on the magnitude of the received voltage.

[0069] In some embodiments, see Figure 3 , Figure 3 This is a circuit diagram of a short-circuit protection circuit provided by an embodiment of the present utility model, such as Figure 3 As shown, the maintaining unit 321 includes a diode D1 and an energy storage capacitor C1; the voltage dividing unit 322 includes a resistor R1 and a resistor R2;

[0070] The anode of the diode D1 is connected to the working circuit 10 , and the cathode of the diode D1 is connected to the energy storage capacitor C1 and the voltage dividing unit 322 , respectively. The energy storage capacitor C1 is also grounded.

[0071] The resistor R1 is connected in series with the resistor R2. The resistor R1 is also connected to the cathode of the diode D1 and the inverting input terminal of the comparison module 33 respectively. The resistor R2 is also grounded.

[0072] Specifically, when the working circuit 10 is operating normally, the output voltage (V0) is input to the resistors R1 and R2 through the diode D1. Simultaneously, the output voltage charges the energy storage capacitor C1 through the diode D1. After receiving the output voltage, the resistors R1 and R2 divide the output voltage and input the divided third voltage to the inverting input of the comparison module 33.

[0073] When the working circuit 10 is short-circuited, the output voltage gradually decreases. When the output voltage is lower than the voltage stored in the energy storage capacitor C1, the output voltage of the working circuit 10 is cut off by the diode D1 due to the unidirectional conductivity of the diode. At this time, the energy storage capacitor C1 begins to discharge into the resistors R1 and R2, so that the resistors R1 and R2 maintain the output of the third voltage to the comparison module 33.

[0074] It can be known that, due to the unidirectional conductivity of the diode D1 , when the voltage stored in the energy storage capacitor C1 is greater than the output voltage, the voltage stored in the energy storage capacitor C1 will not flow back to the working circuit 10 .

[0075] In another embodiment, if Figure 3 As shown, the voltage dividing unit 322 further includes a filter capacitor C2, which is connected in parallel with the resistor R2. The filter capacitor C2 is used to smooth the third voltage to improve the quality of the third voltage.

[0076] In some embodiments, see Figure 3 , the voltage dividing module 31 includes a resistor R3 and a resistor R4;

[0077] The resistor R3 is connected in series with the resistor R4. The resistor R3 is also connected to the working circuit 10 and the non-inverting input terminal of the comparison module 33 respectively. The resistor R4 is also grounded.

[0078] Specifically, when the working circuit 10 is operating normally, the resistors R3 and R4 are used to divide the output voltage, thereby outputting a first voltage to the non-inverting input terminal of the comparison module 33. When the working circuit 10 is short-circuited, the output voltage gradually decreases, and the voltage division value of the resistors R3 and R4 also gradually decreases, thereby outputting a second voltage to the non-inverting input terminal of the comparison module 33.

[0079] It should be noted that the resistance ratio of the resistor R4 to the resistor R3 is greater than the resistance ratio of the resistor R2 to the resistor R1. When the resistance ratio of the resistor R4 to the resistor R3 is greater than the resistance ratio of the resistor R2 to the resistor R1, and the working circuit 10 operates normally, the voltage divided value on the resistor R4 will be greater than the voltage divided value on the resistor R2, thereby causing the comparison module 33 to output the first control signal.

[0080] In yet another embodiment, Figure 2 As shown, the comparison module 33 includes a comparator U1 and a signal locking unit 331;

[0081] The non-inverting input terminal of the comparator U1 is connected to the voltage divider module 31, the inverting input terminal of the comparator U1 is connected to the voltage maintaining module 32, the output terminal of the comparator U1 is connected to the controller 20, and the signal locking unit 331 is connected to the output terminal of the comparator U1 and the non-inverting input terminal of the comparator U1 respectively;

[0082] The comparator U1 is configured to output a first control signal according to the first voltage and the third voltage; and

[0083] outputting a second control signal according to the second voltage and the third voltage;

[0084] The signal locking unit 331 is configured to adjust the voltage division ratio of the voltage dividing module 31 when the comparator U1 outputs the second control signal, so that the comparator U1 continuously outputs the second control signal.

[0085] When the working circuit 10 is short-circuited, the input voltage of the non-inverting input of the comparator U1 will be lower than the voltage of the inverting input of the comparator U1, causing the comparator U1 to output a low-level signal (the second control signal). When the comparator U1 outputs a low-level signal, the signal locking unit 331 also participates in the voltage division of the voltage divider module 31, thereby adjusting the voltage division ratio of the output voltage, causing the voltage input to the non-inverting input of the comparator U1 to decrease, thereby maintaining the output of the second control signal.

[0086] In yet another embodiment, Figure 3 As shown, the signal locking unit 331 includes a resistor R5;

[0087] The resistor R5 is connected to the output terminal of the comparator U1 and the non-inverting input terminal of the comparator U1 respectively.

[0088] Specifically, when the comparator U1 outputs a low-level signal (the second control signal), the second end of the resistor R5 is a low-level signal. When the second end of the resistor R5 is a low-level signal, it is equivalent to the resistor R5 being connected in parallel with the resistor R4, and the resistance of the resistors will become smaller and smaller, thereby reducing the voltage divider value of the non-inverting input of the comparator U1. At this time, even if the output voltage of the working circuit 10 fluctuates, the signal locking unit 331 will maintain the voltage of the non-inverting input of the comparator U1 lower than the voltage of the inverting input, thereby causing the comparator U1 to continue to output the second control signal. Based on this, it is possible to avoid the situation where the second voltage is greater than the third voltage when the output voltage fluctuates, thereby preventing the working circuit 10 from being mistakenly turned on, thereby improving the reliability of the working circuit 10.

[0089] In yet another embodiment, Figure 2As shown, the comparison module 33 further includes a voltage providing unit 332;

[0090] The voltage providing unit 332 is connected to the output terminal of the comparator U1, and the voltage providing unit 332 is also used to connect to the battery 40 in the working circuit 10;

[0091] The voltage providing unit 332 is configured to provide an operating voltage to the non-inverting input terminal of the comparator U1 through the signal locking unit 331 when the operating circuit 10 is not operating, so that the comparator U1 outputs a first control signal to the controller 20 .

[0092] It should be noted that when the working circuit 10 is not operating, the working circuit 10 does not output a voltage. In this case, the comparator U1 may output a second control signal to the controller 20, thereby restricting the activation of the working circuit 10. Therefore, in order to avoid restricting the activation of the working circuit 10 when the working circuit 10 is not activated, a voltage providing unit 332 is provided. When the working circuit 10 is not activated, the voltage providing unit 332 obtains the battery voltage of the battery 40 in the working circuit 10 and inputs the battery voltage to the non-inverting input terminal of the comparator U1 through the resistor R5, thereby making the voltage at the non-inverting input terminal of the comparator U1 greater than the voltage at the inverting input terminal. The comparator U1 then outputs a first control signal to the controller 20 to maintain the current operating state of the working circuit 10.

[0093] In some embodiments, as Figure 3 As shown, the voltage providing unit 332 includes a resistor R6;

[0094] The resistor R6 is connected to the signal locking unit 331 and the battery 40 of the working circuit 10 respectively.

[0095] Specifically, when the working circuit 10 is not working, the resistor R6 receives the battery voltage of the battery 40 and inputs the battery voltage to the non-inverting input terminal of the comparator U1 through the resistor R5, thereby preventing the working circuit 10 from being restricted from starting.

[0096] In another embodiment, the controller 20 includes a diode D2 (not shown), the cathode of which is connected to the output terminal of the comparator U1. Due to the unidirectional conductivity of the diode, the battery voltage can only be input to the non-inverting input terminal of the comparator U1 through the resistor R5 and cannot flow into the controller 20. This improves the stability of the short-circuit protection circuit 30.

[0097] In some embodiments, see Figure 3When the working circuit 10 is operating normally, the output voltage charges the energy storage capacitor C1 through the diode D1, and is also divided by the resistors R1 and R2, and by the resistors R3 and R4. Since the voltage divided by the resistor R2 is greater than the voltage divided by the resistor R4, the comparator U1 outputs a high-level signal (first control signal) to the controller 20, thereby maintaining the working circuit 10 in its current working state. When the working circuit 10 is short-circuited, the output voltage gradually decreases, and the energy storage capacitor C1 discharges the resistors R1 and R2 so that the resistors R1 and R2 still output the third voltage, while the voltage divided by the resistors R3 and R4 decreases as the output voltage decreases. When the voltage divided by the resistors R3 and R4 is less than the voltage divided by the resistors R1 and R2, the comparator U1 outputs a low-level signal, thereby stopping the working circuit 10. Based on this, the short-circuit protection of the working circuit 10 can be achieved through a purely analog circuit, thereby improving the stability and reliability of the power supply.

[0098] The utility model provides a short-circuit protection circuit, comprising a voltage maintaining module, a voltage dividing module, and a comparison module; the voltage maintaining module and the voltage dividing module are respectively connected to the input end of the comparison module, the output end of the comparison module is connected to a controller, and the voltage maintaining module and the voltage dividing module are also connected to a working circuit. The voltage dividing module is used to divide the output voltage of the working circuit and output a first voltage to the comparison module when the working circuit is operating normally, and output a second voltage to the comparison module when the working circuit is short-circuited. The voltage maintaining module is mainly used to store the output voltage and output a third voltage to the comparison module when the working circuit is operating normally. At this time, the comparison module receives the first and third voltages, and because the first voltage is greater than the third voltage, the comparison module outputs a first control signal to the controller to maintain the current operating state of the working circuit. When the working circuit is short-circuited, the voltage maintaining module maintains the output of the third voltage to the comparison module based on the stored voltage, so that the comparison module outputs a second control signal based on the third voltage greater than the second voltage, thereby stopping the working circuit. Based on this, a pure analog circuit can be used to achieve a fast response when the working circuit is short-circuited, thereby improving the reliability of the power supply.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Under the idea of ​​the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above. For the sake of simplicity, they are not provided in detail. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the above embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of this application.

Claims

1. A short circuit protection circuit, characterized in that: The short-circuit protection circuit includes a voltage maintaining module, a voltage dividing module and a comparison module; The voltage maintaining module and the voltage dividing module are respectively connected to the input end of the comparison module, the output end of the comparison module is connected to the controller, and the voltage maintaining module and the voltage dividing module are also connected to the working circuit; The voltage dividing module is used to divide the output voltage of the working circuit to output a first voltage to the comparison module when the working circuit works normally; as well as outputting a second voltage to the comparison module when the working circuit is short-circuited; The voltage maintaining module is used to divide the output voltage of the working circuit to output a third voltage to the comparison module when the working circuit operates normally; as well as storing the output voltage of the working circuit when the working circuit operates normally, so as to continuously output a third voltage to the comparison module when the working circuit is short-circuited, wherein the third voltage is less than the first voltage and greater than the second voltage; The comparison module is configured to output a first control signal to the controller when receiving the first voltage and the third voltage, so as to enable the controller to maintain the working state of the working circuit; as well as When the second voltage and the third voltage are received, a second control signal is output to the controller, so that the controller controls the working circuit to stop working.

2. The short-circuit protection circuit according to claim 1, characterized in that: The voltage maintaining module includes a maintaining unit and a voltage dividing unit; The maintaining unit is connected to the voltage dividing unit, the voltage dividing unit is connected to the inverting input terminal of the comparison module, and the maintaining unit is also connected to the working circuit; The maintaining unit is used to store the output voltage of the working circuit when the working circuit is working normally, and transmit the output voltage of the working circuit to the voltage dividing unit; as well as When the working circuit is short-circuited, outputting the stored voltage to the voltage dividing unit; The voltage dividing unit is used to divide the voltage output by the maintaining unit to output a third voltage to the inverting input terminal of the comparison module.

3. The short-circuit protection circuit according to claim 2, characterized in that: The maintaining unit includes a diode D1 and an energy storage capacitor C1; The anode of the diode D1 is connected to the working circuit, and the cathode of the diode D1 is connected to the energy storage capacitor C1 and the voltage dividing unit respectively. The energy storage capacitor C1 is also used for grounding.

4. The short-circuit protection circuit according to claim 3, characterized in that: The voltage dividing unit includes a resistor R1 and a resistor R2; The resistor R1 is connected in series with the resistor R2. The resistor R1 is also connected to the cathode of the diode D1 and the inverting input terminal of the comparison module respectively. The resistor R2 is also grounded.

5. The short-circuit protection circuit according to claim 1, wherein: The voltage divider module includes a resistor R3 and a resistor R4; The resistor R3 is connected in series with the resistor R4. The resistor R3 is also connected to the working circuit and the non-inverting input terminal of the comparison module respectively. The resistor R4 is also used for grounding.

6. The short-circuit protection circuit according to claim 1, characterized in that: The comparison module includes a comparator U1 and a signal locking unit; The non-inverting input terminal of the comparator U1 is connected to the voltage divider module, the inverting input terminal of the comparator U1 is connected to the voltage maintaining module, the output terminal of the comparator U1 is connected to the controller, and the signal locking unit is connected to the output terminal of the comparator U1 and the non-inverting input terminal of the comparator U1 respectively; The comparator U1 is used to output a first control signal according to the first voltage and the third voltage; as well as outputting a second control signal according to the second voltage and the third voltage; The signal locking unit is configured to adjust the voltage division ratio of the voltage division module when the comparator U1 outputs the second control signal, so that the comparator U1 continuously outputs the second control signal.

7. The short-circuit protection circuit according to claim 6, characterized in that: The signal locking unit includes a resistor R5; The resistor R5 is connected to the output terminal of the comparator U1 and the non-inverting input terminal of the comparator U1 respectively.

8. The short-circuit protection circuit according to claim 6, characterized in that: The comparison module also includes a voltage providing unit; The voltage providing unit is connected to the output terminal of the comparator U1, and the voltage providing unit is also used to connect to a battery; The voltage providing unit is used to provide an operating voltage to the non-inverting input terminal of the comparator U1 through the signal locking unit when the operating circuit is not operating, so that the comparator U1 outputs a first control signal to the controller.

9. The short-circuit protection circuit according to claim 8, characterized in that: The voltage providing unit includes a resistor R6; The resistor R6 is connected to the signal locking unit and the battery of the working circuit respectively.

10. A power supply system, characterized in that: The power supply system comprises: Battery; Controller; operating circuit; and The short-circuit protection circuit according to any one of claims 1 to 9.

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