Overcurrent protection circuit and power supply device

Abstract

This application discloses an overcurrent protection circuit and a power supply device. The overcurrent protection circuit includes a sampling branch, a comparison branch, a power output control branch, a self-locking branch, and a switching branch. The sampling branch samples the current flowing between a first ground and a second ground and generates a first sampling voltage based on the current. The first ground is the ground of the overcurrent protection circuit. The comparison branch outputs a first comparison signal when the first sampling voltage is greater than or equal to a first reference voltage. The power output control branch stops outputting the first power supply to the power-consuming device when it receives the first comparison signal. The second ground is the ground of the power-consuming device. The self-locking branch outputs a self-locking signal when it receives the first comparison signal. The switching branch turns on when it receives the self-locking signal and outputs a low-level signal to the comparison branch so that the comparison branch maintains the output of the first comparison signal. This method can be applied to different application scenarios to achieve overcurrent protection and has strong practicality.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to an overcurrent protection circuit and power supply equipment. Background Technology

[0002] In applications where power supply equipment provides power to electrical devices via power cables, an abnormality in the electrical device or power cable (such as a short circuit) will increase the power load on the power supply equipment and lead to an increase in current. When the current exceeds the power output capacity of the power supply equipment, voltage fluctuations will occur, causing malfunctions in the power supply equipment and potentially damaging it.

[0003] Currently, to solve the above problems, a dedicated overcurrent protection chip is typically connected between one end of the power supply output and the power-consuming equipment to provide overcurrent protection. However, this method requires replacing the overcurrent protection chip based on different application scenarios, i.e., different current limits, making it less practical. Summary of the Invention

[0004] This application aims to provide an overcurrent protection circuit and power supply device that can be applied to different application scenarios to achieve overcurrent protection and has strong practicality.

[0005] To achieve the above objectives, in a first aspect, this application provides an overcurrent protection circuit, comprising:

[0006] A sampling branch is connected between a first ground and a second ground. The sampling branch is used to sample the current flowing between the first ground and the second ground, and to generate a first sampling voltage based on the current. The first ground is the ground of the overcurrent protection circuit.

[0007] A comparison branch is provided, wherein a first reference voltage is input at its first end, and a second end of the comparison branch is connected to the sampling branch. The comparison branch is used to output a first comparison signal when the first sampling voltage is greater than or equal to the first reference voltage.

[0008] A power output control branch is provided, which is connected to the comparison branch and is connected between the first power supply and the electrical device. The power output control branch is used to stop outputting the first power supply to the electrical device when the first comparison signal is received, wherein the second ground is the ground of the electrical device.

[0009] A self-locking branch is connected to the comparison branch, and the self-locking branch is used to output a self-locking signal when the first comparison signal is received;

[0010] A switching branch is connected between the self-locking branch and the comparison branch. The switching branch is used to turn on when the self-locking signal is received and output a low-level signal to the first terminal of the comparison branch so that the comparison branch continues to output the first comparison signal.

[0011] In one alternative, the first terminal of the comparison branch is further input with a second reference voltage, and the comparison branch is further configured to output a second comparison signal when the first sampling voltage is less than the second reference voltage, wherein the second reference voltage is less than the first reference voltage;

[0012] The power output control branch is also used to output the first power supply to the electrical equipment when the second comparison signal is received;

[0013] The self-locking branch is also used to stop outputting the self-locking signal when the second comparison signal is received;

[0014] The switch branch is also used to turn off when the latching signal is not received, so as to stop outputting the low-level signal.

[0015] In one alternative embodiment, the overcurrent protection circuit further includes an amplification branch;

[0016] The amplification branch is connected between the sampling branch and the comparison branch, and the amplification branch is used to amplify the first sampling voltage and output the second sampling voltage.

[0017] The comparison branch is also used to output the first comparison signal when the second sampling voltage is greater than or equal to the first reference voltage.

[0018] In one alternative embodiment, the overcurrent protection circuit further includes a self-locking recovery branch and a controller;

[0019] The controller is connected to the comparison branch, and the controller is used to output a first control signal after delaying a first preset time after receiving the first comparison signal;

[0020] The self-locking recovery branch is connected to the controller, and the self-locking recovery branch is used to output a self-locking recovery signal when the first control signal is received;

[0021] The switch branch is connected to the self-locking recovery branch. The switch branch is also used to turn on when the self-locking signal is received but the self-locking recovery signal is not received, and to turn off when the self-locking recovery signal is received, so as to stop outputting the low-level signal.

[0022] In one alternative approach, the sampling branch includes a first resistor;

[0023] The first resistor is connected between the first ground and the second ground.

[0024] In one alternative embodiment, the comparison branch includes a second resistor, a third resistor, a fourth resistor, and a first comparator;

[0025] The second resistor and the third resistor are connected in series between the second power supply and the first ground. The connection point between the second resistor and the third resistor is connected to the first input terminal of the first comparator. The fourth resistor is connected between the output terminal and the first input terminal of the first comparator. The second input terminal of the first comparator is connected to the sampling branch.

[0026] In one alternative embodiment, the power output control branch includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a first switching transistor, and a second switching transistor.

[0027] The fifth resistor, the sixth resistor, and the seventh resistor are connected in series between the comparison branch and the first ground. The connection point between the sixth resistor and the seventh resistor is connected to the first terminal of the first switching transistor. The second terminal of the first switching transistor is connected to the first ground. The eighth resistor is connected between the third terminal of the first switching transistor and the first terminal of the second switching transistor. The ninth resistor is connected between the first power supply and the first terminal of the second switching transistor. The first capacitor and the ninth resistor are connected in parallel. The second terminal of the second switching transistor is connected to the first power supply. The third terminal of the second switching transistor is connected to the electrical equipment.

[0028] In one alternative embodiment, the self-locking branch includes a tenth resistor, an eleventh resistor, and a third switching transistor;

[0029] The tenth resistor is connected to the second power supply and the first terminal of the third switch transistor. The second terminal of the third switch transistor is connected to the second power supply. The third terminal of the third switch transistor is connected to the switch branch through the eleventh resistor.

[0030] In one alternative embodiment, the switching branch includes a fourth switching transistor;

[0031] The first end of the fourth switch is connected to the self-locking branch, the second end of the fourth switch is connected to the first ground, and the third end of the fourth switch is connected to the first end of the comparison branch.

[0032] In one alternative embodiment, the amplification branch includes a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a second capacitor, and a first operational amplifier;

[0033] The twelfth resistor and the sixteenth resistor are connected in series between the output terminal of the first operational amplifier and the first ground. The connection point between the twelfth resistor and the sixteenth resistor is connected to the second input terminal of the first operational amplifier. The second capacitor is connected between the output terminal of the first operational amplifier and the first ground. The output terminal of the first operational amplifier is connected to the comparator branch. The thirteenth resistor and the fourteenth resistor are connected in series between the second power supply and the second ground. The connection point between the thirteenth resistor and the fourteenth resistor is connected to the first input terminal of the first operational amplifier. The fifteenth resistor is connected between the first input terminal of the first operational amplifier and the first ground.

[0034] In one alternative embodiment, the self-locking recovery circuit includes a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, and a fifth switching transistor;

[0035] The seventeenth resistor and the eighteenth resistor are connected in series between the controller and the first ground. The connection point between the seventeenth resistor and the eighteenth resistor is connected to the first end of the fifth switch transistor. The second end of the fifth switch transistor is connected to the first ground. The third end of the fifth switch transistor is connected to the switch branch. The nineteenth resistor is connected between the second end and the third end of the fifth switch transistor.

[0036] Secondly, this application provides a power supply device, which includes the overcurrent protection circuit described above.

[0037] The beneficial effects of this application are as follows: The overcurrent protection circuit provided by this application includes a sampling branch, a comparison branch, a power output control branch, a self-locking branch, and a switching branch. First, the sampling branch samples the current flowing between a first ground and a second ground, and generates a first sampling voltage based on the current. When an abnormality occurs in the electrical equipment or power supply cable, causing an increase in the current between the first ground and the second ground, the first sampling voltage will increase to be greater than or equal to a first reference voltage. At this time, the comparison branch outputs a first comparison signal. The first comparison signal is input to the power output control branch, which immediately stops outputting the first power supply to the electrical equipment, thereby realizing the overcurrent protection function. Second, by adjusting the magnitude of the first reference voltage, the magnitude of the current triggering overcurrent protection is also adjusted, thus making it applicable to different application scenarios for overcurrent protection. Furthermore, the first comparison signal is also simultaneously input to the self-locking branch, causing the self-locking branch to output a self-locking signal to the switching branch. The switching branch is turned on and outputs a low-level signal to the first terminal of the comparison branch to pull the potential of the first terminal of the comparison branch low. Because the voltage at the first terminal of the comparison branch is pulled low, the voltage at the second terminal of the comparison branch (which is the first sampling voltage) can be kept greater than the voltage at the first terminal of the comparison branch, thereby ensuring that the comparison branch continues to output the first comparison signal. This ensures the reliable implementation of the overcurrent protection function and is beneficial for providing effective overcurrent protection for electrical equipment and power supply equipment. Attached Figure Description

[0038] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0039] Figure 1 This is a schematic diagram of the overcurrent protection circuit provided in Embodiment 1 of this application;

[0040] Figure 2 This is a schematic diagram of the overcurrent protection circuit provided in Embodiment 2 of this application;

[0041] Figure 3 This is a schematic diagram of the overcurrent protection circuit provided in Embodiment 3 of this application;

[0042] Figure 4 This is a schematic diagram of the overcurrent protection circuit provided in Embodiment 4 of this application;

[0043] Figure 5 This is a schematic diagram of the overcurrent protection circuit provided in Embodiment 1 of this application. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the overcurrent protection circuit provided in an embodiment of this application. Figure 1 As shown, the overcurrent protection circuit 100 includes a sampling branch 10, a comparison branch 20, a power output control branch 30, a self-locking branch 40, and a switching branch 50.

[0046] The sampling branch 10 is connected between the first ground GND1 and the second ground GND2. The comparison branch 20 is connected to the sampling branch 10, the power output control branch 30, and the self-locking branch 40. Specifically, the first terminal of the comparison branch 20 receives the first reference voltage VREF1, the second terminal of the comparison branch 20 is connected to the sampling branch 10, and the third terminal of the comparison branch 20 is connected to the first terminal of the power output control branch 30 and the first terminal of the self-locking branch 40. The power output control branch 30 is connected between the first power supply V1 and the electrical equipment 200. The switch branch 50 is connected between the second terminal of the self-locking branch 40 and the first terminal of the comparison branch 20.

[0047] Specifically, sampling branch 10 is used to sample the current flowing between the first ground GND1 and the second ground GND2, and generate a first sampling voltage based on the current. The first ground GND1 is the ground of the overcurrent protection circuit 100. Comparison branch 20 is used to output a first comparison signal when the first sampling voltage is greater than or equal to the first reference voltage VREF1. Power output control branch 30 is used to stop outputting the first power supply V1 to the electrical device 200 upon receiving the first comparison signal. The second ground GND2 is the ground of the electrical device 200. Locking branch 40 is used to output a locking signal upon receiving the first comparison signal. Switching branch 50 is used to turn on upon receiving the locking signal and output a low-level signal to the first terminal of comparison branch 20, so that comparison branch 20 maintains the output of the first comparison signal.

[0048] In practical applications, firstly, sampling branch 10 samples the current flowing between the first ground GND1 and the second ground GND2, and generates a first sampling voltage based on the current. When an abnormality occurs in the electrical device 200 or the power supply cable (the cable between the electrical device 200 and the power supply equipment including the overcurrent protection circuit 100) (e.g., a short circuit), causing an increase in the current between the first ground GND1 and the second ground GND2, the first sampling voltage increases to be greater than or equal to the first reference voltage VREF1. At this time, comparison branch 20 outputs a first comparison signal (high-level signal or low-level signal). The first comparison signal is input to the power output control branch 30, and the power output control branch 30 immediately stops outputting the first power supply V1 to the electrical device 200, thereby realizing the overcurrent protection function.

[0049] Furthermore, if the required current limiting magnitude differs in different application scenarios, the magnitude of the first sampling voltage corresponding to the output of the first comparison signal by the trigger comparison branch 20 can be adjusted by adjusting the magnitude of the first reference voltage VREF, which in turn corresponds to adjusting the current magnitude when the overcurrent protection function is triggered. Therefore, the embodiments of this application can be applied to different application scenarios to implement overcurrent protection.

[0050] Furthermore, in this embodiment, the first comparison signal is also simultaneously input to the self-locking branch 40, so that the self-locking branch 40 outputs a self-locking signal to the switching branch 50. Then, the switching branch 50 is turned on and outputs a low-level signal to the first terminal of the comparison branch 20, pulling down the potential of the first terminal of the comparison branch 20. The voltage at the first terminal of the comparison branch 20 then decreases from the first reference voltage VREF1 to 0V or near 0V. Obviously, the first sampling voltage is now necessarily greater than the voltage at the first terminal of the comparison branch 20, meaning the voltage at the second terminal of the comparison branch 20 can remain greater than the voltage at the first terminal of the comparison branch 20, thus enabling the comparison branch 20 to maintain the output of the first comparison signal. This ensures the reliable implementation of the overcurrent protection function, effectively protecting the electrical equipment 200 and the power supply equipment including the overcurrent protection circuit 100 from overcurrent.

[0051] In one embodiment, such as Figure 2 As shown, the first terminal of the comparison branch 20 receives either a first reference voltage VREF1 or a second reference voltage VREF2. The second reference voltage VREF2 is less than the first reference voltage VREF1 to achieve a hysteresis comparison process.

[0052] Specifically, the comparison branch 20 is also used to output a second comparison signal (high-level signal or low-level signal) when the first sampling voltage is less than the second reference voltage VREF2. The power output control branch 30 is also used to output a first power supply V1 to the electrical device 200 when the second comparison signal is received. The self-locking branch 40 is also used to stop outputting the self-locking signal when the second comparison signal is received. The switch branch 50 is also used to turn off when no self-locking signal is received, so as to stop outputting the low-level signal.

[0053] In practical applications, when an abnormality occurs in the electrical equipment 200 or its power supply cable (e.g., a short circuit) causing the first sampling voltage to increase to a level greater than or equal to the first reference voltage VREF1, the comparison branch 20 outputs a first comparison signal, causing the power output control branch 30 to control the first power supply V1 to supply power to the electrical equipment 200. Conversely, when the first sampling voltage decreases to a level less than the second reference voltage VREF2, the comparison branch 20 outputs a second comparison signal, causing the power output control branch 30 to control the first power supply V1 to stop supplying power to the electrical equipment 200. This process thus realizes the hysteresis comparison process.

[0054] By setting a hysteresis comparison process, the abnormal situation of repeatedly switching between the states of the first power supply V1 supplying power to the device 200 and the first power supply V1 not supplying power to the device 200 can be prevented when the current flowing between the first ground GND1 and the second ground GND2 fluctuates due to factors such as interference. For example, if the first sampling voltage is lower than the first reference voltage VREF1 at certain times or for certain periods due to current fluctuations, and if the second reference voltage VREF2 is not set, the first sampling voltage will fluctuate around the first reference voltage VREF1, resulting in the abnormal situation of repeatedly switching between the states of the first power supply V1 supplying power to the device 200 and the first power supply V1 not supplying power to the device 200. However, by setting the second reference voltage VREF2, the power output control branch 30 will only control the first power supply V1 to supply power to the device 200 when the first sampling voltage decreases to be lower than the second reference voltage VREF2. It is evident that by simply setting the difference between the first reference voltage VREF1 and the second reference voltage VREF2 according to different application scenarios, and preventing the first sampling voltage from being less than the second reference voltage VREF2 due to current fluctuations, the abnormal situation of repeated switching between the two states of the first power supply V1 supplying power to the electrical equipment 200 and the first power supply V1 stopping supplying power to the electrical equipment 200 can be effectively prevented, which is conducive to improving the reliability of the overcurrent protection function.

[0055] It is understandable that the first comparison signal and the second comparison signal are different. Specifically, the first comparison signal is a high-level signal and the second comparison signal is a low-level signal; or, the first comparison signal is a low-level signal and the second comparison signal is a high-level signal.

[0056] In one embodiment, such as Figure 3 As shown, the overcurrent protection circuit 100 also includes an amplification branch 60. The amplification branch 60 is connected between the sampling branch 10 and the comparison branch 20.

[0057] Specifically, the amplification branch 60 amplifies the first sampling voltage and outputs a second sampling voltage. The comparison branch 60 is also used to output a first comparison signal when the second sampling voltage is greater than or equal to the first reference voltage VREF1. Furthermore, the comparison branch 60 is also used to output a second comparison signal when the second sampling voltage is less than the second reference voltage VREF2.

[0058] In this embodiment, by setting up an amplification branch 60 to amplify the first sampling voltage, the strength and clarity of the sampled signal can be enhanced, so as to achieve effective transmission of the sampled signal and thereby improve the reliability of the subsequent overcurrent protection function.

[0059] In one embodiment, such as Figure 4 As shown, the overcurrent protection circuit 100 also includes a self-locking recovery branch 70 and a controller 80. The controller 80 is connected to both the comparison branch 20 and the self-locking recovery branch 70, and the switch branch 50 is connected to the self-locking recovery branch 70.

[0060] Specifically, the controller 80 is configured to output a first control signal (high-level signal or low-level signal) after a first preset time delay following receipt of the first comparison signal. The self-locking recovery branch 70 is configured to output a self-locking recovery signal upon receiving the first control signal. The switch branch 50 is further configured to be turned on when a self-locking signal is received but a self-locking recovery signal is not received, and to be turned off upon receiving a self-locking recovery signal, thereby stopping the output of the low-level signal.

[0061] The first preset duration is a pre-set duration that can be set according to the actual application scenario. This application embodiment does not impose specific restrictions on it.

[0062] In this embodiment, when the controller 80 receives the first comparison signal, the controller 80 determines that the overcurrent protection function has been triggered. Then, the controller 80 times a first preset duration. At the end of the first preset duration, the controller 80 assumes that the abnormality causing the overcurrent has been recovered and can restore power to the electrical equipment 200. At this time, the controller 80 outputs a first control signal to the self-locking recovery branch 70. Subsequently, the self-locking recovery branch 70 outputs a self-locking recovery signal to the switching branch 50, causing the switching branch 50 to turn off and stop outputting low-level signals. In this case, if the current flowing between the first ground GND1 and the second ground GND2 has returned to normal, the second sampling voltage output by the amplification branch 60 is less than the second reference voltage VREF2, and the comparison branch 20 outputs a second comparison signal. On one hand, when the power output control branch 30 receives the second comparison signal, it outputs the first power supply V1 to power the electrical device 200. On the other hand, when the self-locking branch 40 receives the second comparison signal, it stops outputting the self-locking signal, so that the comparison branch 20 continues to output the second comparison signal, thereby enabling the power output control branch 30 to control the first power supply V1 to continue supplying power to the electrical device 200. Thus, the process of automatically restoring power to the electrical device 200 after a first preset time following an overcurrent event is achieved, providing a better user experience.

[0063] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the circuit structure of the overcurrent protection circuit 100 provided in the embodiments of this application.

[0064] In one embodiment, such as Figure 5 As shown, sampling branch 10 includes a first resistor R1.

[0065] The first resistor R1 is connected between the first ground GND1 and the second ground GND2.

[0066] Specifically, the current between the first ground GND1 and the second ground GND2 flows through the first resistor R1 to generate a first sampling voltage across the first resistor R1.

[0067] In one embodiment, the comparison branch 20 includes a second resistor R2, a third resistor R3, a fourth resistor R4, and a first comparator U1.

[0068] The second resistor R2 and the third resistor R3 are connected in series between the second power supply V2 and the first ground GND1. The connection point between the second resistor R2 and the third resistor R3 is connected to the first input terminal of the first comparator U1. The fourth resistor R4 is connected between the output terminal and the first input terminal of the first comparator U1. The second input terminal of the first comparator U1 is connected to the sampling branch 10 through the amplification branch 60.

[0069] In this embodiment, the first input terminal of the first comparator U1 is the non-inverting input terminal, and the second input terminal is the inverting input terminal. Furthermore, in this embodiment, the first comparison signal is a low-level signal, and the second comparison signal is a high-level signal.

[0070] Specifically, the combination of the second resistor R2, the third resistor R3, the fourth resistor R4, and the first comparator U1 enables a hysteresis comparison process. The first reference voltage VREF1 = V2 * R3 / [(R2||R4) + R3], where R2||R4 represents the total resistance of the second resistor R2 and the third resistor R3 connected in parallel. The second reference voltage VREF2 = V2 * (R3||R4) / [(R3||R4) + R2]. R3||R4 represents the total resistance of the third resistor R3 and the fourth resistor R4 connected in parallel. Therefore, by adjusting the resistance value of at least one of the second resistor R2, the third resistor R3, and the fourth resistor R4, the first reference voltage VREF1 and / or the second reference voltage VREF2 can be adjusted to regulate the current threshold triggering overcurrent protection. This allows the overcurrent protection circuit 100 to be applicable to application scenarios with different current limiting requirements, making it highly practical.

[0071] In one embodiment, the power output control branch 30 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a first capacitor C1, a first switch Q1, and a second switch Q2.

[0072] Among them, the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 are connected in series between the output terminal of the first comparator U1 in the comparison branch 10 and the first ground GND1. The connection point between the sixth resistor R6 and the seventh resistor R7 is connected to the first terminal of the first switch Q1. The second terminal of the first switch Q1 is connected to the first ground GND1. The eighth resistor R8 is connected between the third terminal of the first switch Q1 and the first terminal of the second switch Q2. The ninth resistor R9 is connected between the first power supply V1 and the first terminal of the second switch Q2. The first capacitor C1 is connected in parallel with the ninth resistor R9. The second terminal of the second switch Q2 is connected to the first power supply V1. The third terminal of the second switch Q2 is connected to the electrical equipment 200.

[0073] Specifically, resistors R5, R6, and R8 are all used for current limiting. Resistor R7 provides the on-state voltage drop for the first switch Q1. Resistor R9 provides the on-state voltage drop for the second switch Q2. Capacitor C1 is used for filtering.

[0074] When the first comparator U1 outputs the first comparison signal (i.e., a low-level signal), the first comparison signal is input to the base of the first switching transistor Q1, causing the first switching transistor Q1 to turn off. Subsequently, the second switching transistor Q2 also turns off, the connection between the first power supply V1 and the electrical device 200 is disconnected, and the first power supply V1 stops supplying power to the electrical device 200.

[0075] When the first comparator U1 outputs the second comparison signal (i.e., a high-level signal), the second comparison signal is input to the base of the first switching transistor Q1, causing the first switching transistor Q1 to conduct. Subsequently, the second switching transistor Q2 also conducts, and the connection between the first power supply V1 and the electrical device 200 is established, with the first power supply V1 supplying power to the electrical device 200.

[0076] In this embodiment, the first switching transistor Q1 is an NPN transistor. The base of the NPN transistor is the first terminal of the first switching transistor Q1, the emitter of the NPN transistor is the second terminal of the first switching transistor Q1, and the collector of the NPN transistor is the third terminal of the first switching transistor Q1.

[0077] Meanwhile, taking the second switch Q2 as a PMOS transistor as an example, the gate of the PMOS transistor is the first terminal of the second switch Q2, the source of the PMOS transistor is the second terminal of the second switch Q2, and the drain of the PMOS transistor is the third terminal of the second switch Q2.

[0078] In addition, the first switch Q1 and the second switch Q2 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0079] In one embodiment, the self-locking branch 40 includes a tenth resistor R10, an eleventh resistor R11, and a third switch Q3.

[0080] The tenth resistor R10 is connected to the second power supply V2 and the first terminal of the third switch Q3. The second terminal of the third switch Q3 is connected to the second power supply V2, and the third terminal of the third switch Q3 is connected to the switch branch 50 through the eleventh resistor R11. The tenth resistor R10 is a pull-up resistor.

[0081] Specifically, when the first comparison signal (i.e., a low-level signal) is input to the first terminal of the third switch Q3, the third switch Q3 is turned on. The second power supply V2 acts on the switch branch 50 through the third switch Q3 and the eleventh resistor R11, corresponding to the output of the self-locking signal from the self-locking branch 40 to the switch branch 50.

[0082] When the second comparison signal (i.e., a high-level signal) is input to the first terminal of the third switch Q3, the third switch Q3 is turned off. The connection between the second power supply V2 and the switch branch 50 is disconnected, corresponding to the self-locking branch 40 stopping the output of the self-locking signal to the switch branch 50.

[0083] In this embodiment, the third switch Q3 is a PMOS transistor. The gate of the PMOS transistor is the first terminal of the third switch Q3, the source of the PMOS transistor is the second terminal of the third switch Q3, and the drain of the PMOS transistor is the third terminal of the third switch Q3.

[0084] In addition, the third switch Q3 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0085] In one embodiment, the switching branch 50 includes a fourth switching transistor Q4.

[0086] The first end of the fourth switch Q4 is connected to the self-locking branch 40 and the self-locking recovery branch 70, the second end of the fourth switch Q4 is connected to the first ground GND1, and the third end of the fourth switch Q4 is connected to the first end of the comparison branch 20.

[0087] Specifically, when the first terminal of the fourth switch Q4 receives a latching signal and a latching recovery signal, the fourth switch Q4 is turned on, connecting the first terminal of the comparator branch 20 to the first ground GND1, corresponding to inputting a low-level signal to the first terminal of the comparator branch 20. When the first terminal of the fourth switch Q4 receives a latching recovery signal or no latching signal, the fourth switch Q4 is turned off, disconnecting the connection between the first terminal of the comparator branch 20 and the first ground GND1, corresponding to stopping the output of a low-level signal to the first terminal of the comparator branch 20.

[0088] In this embodiment, the fourth switch Q4 is an NMOS transistor. The gate of the NMOS transistor is the first terminal of the fourth switch Q4, the source of the NMOS transistor is the second terminal of the fourth switch Q4, and the drain of the NMOS transistor is the third terminal of the fourth switch Q4.

[0089] In addition, the fourth switch Q4 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0090] In one embodiment, the amplification branch 60 includes a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a second capacitor C2, and a first operational amplifier U2.

[0091] In this embodiment, the twelfth resistor R12 and the sixteenth resistor R16 are connected in series between the output terminal of the first operational amplifier U2 and the first ground GND1. The connection point between the twelfth resistor R12 and the sixteenth resistor R16 is connected to the second input terminal of the first operational amplifier U2. The second capacitor C2 is connected between the output terminal of the first operational amplifier U2 and the first ground GND1. The output terminal of the first operational amplifier U2 is connected to the comparator branch 20. The thirteenth resistor R13 and the fourteenth resistor R14 are connected in series between the second power supply V2 and the second ground GND2. The connection point between the thirteenth resistor R13 and the fourteenth resistor R14 is connected to the first input terminal of the first operational amplifier U2. The fifteenth resistor R15 is connected between the first input terminal of the first operational amplifier U2 and the first ground GND1. In this embodiment, the first input terminal of the first operational amplifier U2 is the non-inverting input terminal, and the second input terminal is the inverting input terminal.

[0092] Specifically, resistors R12 (twelfth) and R16 (sixteenth) are used to configure the amplification factor of amplification branch 60. Resistor R13 (thirteenth) is used to match the input impedance of the first operational amplifier U2. Resistors R14 (fourteenth) and R15 (fifteenth) are used to control the static bias voltage of the output voltage of the first operational amplifier U2. For example, when the first sampling voltage is 0, that is, when the input voltages of the non-inverting and inverting input terminals of the first operational amplifier U2 are zero, the first operational amplifier U2 will output a low voltage (e.g., 0.1V).

[0093] In practical applications, when the self-locking branch 40 has output a self-locking signal, the internal resistance of the fourth switch Q4 when it is turned on may cause the voltage at the first terminal of the comparator branch 20 to be very close to 0V but not 0V. At this time, if a static bias voltage is not set for the first operational amplifier U2, the voltage at the non-inverting input terminal of the first comparator U1 will be greater than the voltage at the inverting input terminal, which will cause the first comparator U1 to output a second comparison signal and stop the self-locking branch 40 from outputting a self-locking signal. However, in this embodiment, by setting the fourteenth resistor R14 and the fifteenth resistor R15, it is possible to keep the voltage at the non-inverting input terminal of the first comparator U1 less than the voltage at the inverting input terminal when the self-locking branch 40 has output a self-locking signal, so that the first comparator U1 continues to output the first comparison signal, thereby making the overcurrent protection circuit 100 more reliable.

[0094] In one embodiment, the self-locking recovery circuit 70 includes a seventeenth resistor R17, an eighteenth resistor R18, a nineteenth resistor R19, and a fifth switch Q5.

[0095] Among them, the seventeenth resistor R17 and the eighteenth resistor R18 are connected in series between the controller 80 and the first ground GND1. The connection point between the seventeenth resistor R17 and the eighteenth resistor R18 is connected to the first terminal of the fifth switch Q5. The second terminal of the fifth switch Q5 is connected to the first ground GND1. The third terminal of the fifth switch Q5 is connected to the switch branch 50. The nineteenth resistor R19 is connected between the second terminal and the third terminal of the fifth switch Q5.

[0096] When the controller 80 outputs a first control signal (a high-level signal in this embodiment) to the first terminal of the fifth switch Q5, the fifth switch Q5 is turned on. The first terminal of the fourth switch Q4 is connected to the first ground GND1 through the fifth switch Q5, corresponding to the output of a self-locking recovery signal to the switch branch 40. Subsequently, the fourth switch Q4 is turned off.

[0097] In this embodiment, the fifth switch Q5 is an NPN transistor. The base of the NPN transistor is the first terminal of the fifth switch Q5, the emitter of the NPN transistor is the second terminal of the fifth switch Q5, and the collector of the NPN transistor is the third terminal of the fifth switch Q5.

[0098] In addition, the fifth switch Q5 can be any controllable switch, such as an insulated gate bipolar transistor (IGBT) device, an integrated gate commutated thyristor (IGCT) device, a gate turn-off thyristor (GTO) device, a silicon controlled rectifier (SCR) device, a junction gate field-effect transistor (JFET) device, a MOS controlled thyristor (MCT) device, etc.

[0099] The following are Figure 5 The principle of the circuit structure shown will be explained again.

[0100] The current between the first ground GND1 and the second ground GND2 flows through the first resistor R1 to generate a first sampling voltage across the first resistor R1. The first sampling voltage is input to the first operational amplifier U2, and after being amplified, the first operational amplifier U2 outputs a second sampling voltage to the inverting input of the first comparator U1.

[0101] When no overcurrent fault occurs, the second sampling voltage is less than the second reference voltage VREF2, and the first comparator U2 outputs a second comparison signal (i.e., a high-level signal). The high-level signal is input to the gate of the third switch Q3 to keep the third switch Q3 off; the high-level signal is input to the base of the first switch Q1 to turn on the first switch Q1 and turn on the second switch Q2, and the first power supply V1 supplies power to the electrical device 200; the high-level signal is also input to the controller 80 to determine that no overcurrent has occurred at this time.

[0102] When an overcurrent fault occurs, the second sampling voltage increases to be greater than or equal to the first reference voltage VREF1. The first comparator U1 outputs a first comparison signal (i.e., a low-level signal). Firstly, the first comparison signal is input to the gate of the third switch Q3, causing the third switch Q3 to conduct. The second power supply V2, through the third switch Q3 and the eleventh resistor R11, acts on the fourth switch Q4, causing the fourth switch Q4 to conduct. The first input terminal of the first comparator U1 is connected to the first ground GND1 through the fourth switch Q4, so that the first comparator U1 maintains the output of the first comparison signal. Secondly, the first comparison signal is input to the base of the first switch Q1, causing the first switch Q1 to turn off. Subsequently, the second switch Q2 also turns off, the connection between the first power supply V1 and the electrical equipment 200 is disconnected, and the first power supply V1 stops supplying power to the electrical equipment, thereby realizing the overcurrent protection function. Thirdly, the first comparison signal is input to the controller 80, so that the controller 80 determines that an overcurrent fault has occurred. Subsequently, after a first preset delay, the controller 80 outputs a first control signal (i.e., a high-level signal) to the base of the fifth switch Q5 to turn on the fifth switch Q5. The gate of the fourth switch Q4 is connected to the first ground GND1 through the fifth switch Q5, and the fourth switch Q4 is turned off to stop the self-locking function.

[0103] In this embodiment, if the required current limiting magnitude varies depending on the application scenario, the magnitude of the first reference voltage VREF can be adjusted to adjust the magnitude of the first sampling voltage corresponding to the output of the first comparison signal by the trigger comparison branch 20, which in turn corresponds to adjusting the current magnitude when the overcurrent protection function is triggered. Therefore, the embodiments of this application can be applied to different application scenarios to implement overcurrent protection.

[0104] Secondly, by setting a self-locking branch 40, the reliable implementation of the overcurrent protection function is ensured, which is beneficial to the effective overcurrent protection of the electrical equipment 200 and the power supply equipment including the overcurrent protection circuit 100.

[0105] Furthermore, by setting the first reference voltage VREF1 and the second reference voltage VREF2 to achieve the hysteresis comparison process, it is possible to prevent the abnormal situation of repeated switching between the two states of the first power supply V1 supplying power to the electrical equipment 200 and the first power supply V1 stopping supplying power to the electrical equipment 200 when the current flowing through the first ground GND1 and the second ground GND2 is affected by factors such as interference.

[0106] In addition, after waiting for a first preset time after an overcurrent occurs, it can automatically resume power supply to the electrical equipment, thus providing a better user experience.

[0107] This application also provides a power supply device, which includes the overcurrent protection circuit found in any embodiment of this application. The power supply device supplies power to the electrical device via a power cable.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above, which are not provided in detail for the sake of brevity; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An overcurrent protection circuit, characterized in that, include: A sampling branch is connected between a first ground and a second ground. The sampling branch is used to sample the current flowing between the first ground and the second ground, and to generate a first sampling voltage based on the current. The first ground is the ground of the overcurrent protection circuit. A comparison branch is provided, wherein a first reference voltage is input at the first end of the comparison branch, and a second end of the comparison branch is connected to the sampling branch. The comparison branch is used to output a first comparison signal when the first sampling voltage is greater than or equal to the first reference voltage. A power output control branch is provided, which is connected to the comparison branch and is connected between the first power supply and the electrical device. The power output control branch is used to stop outputting the first power supply to the electrical device when the first comparison signal is received, wherein the second ground is the ground of the electrical device. A self-locking branch is connected to the comparison branch, and the self-locking branch is used to output a self-locking signal when the first comparison signal is received; A switching branch is connected between the self-locking branch and the comparison branch. The switching branch is used to turn on when the self-locking signal is received and output a low-level signal to the first terminal of the comparison branch so that the comparison branch continues to output the first comparison signal. The first terminal of the comparison branch is also input with a second reference voltage, and the comparison branch is also used to output a second comparison signal when the first sampling voltage is less than the second reference voltage, wherein the second reference voltage is less than the first reference voltage; The power output control branch is also used to output the first power supply to the electrical equipment when the second comparison signal is received; The self-locking branch is also used to stop outputting the self-locking signal when the second comparison signal is received; The switch branch is also used to turn off when the self-locking signal is not received, so as to stop outputting the low-level signal; The overcurrent protection circuit also includes a self-locking recovery branch and a controller; The controller is connected to the comparison branch, and the controller is used to output a first control signal after delaying a first preset time after receiving the first comparison signal; The self-locking recovery branch is connected to the controller, and the self-locking recovery branch is used to output a self-locking recovery signal when the first control signal is received; The switch branch is connected to the self-locking recovery branch. The switch branch is also used to turn on when the self-locking signal is received but the self-locking recovery signal is not received, and to turn off when the self-locking recovery signal is received, so as to stop outputting the low-level signal.

2. The overcurrent protection circuit according to claim 1, characterized in that, The overcurrent protection circuit also includes an amplification branch; The amplification branch is connected between the sampling branch and the comparison branch, and the amplification branch is used to amplify the first sampling voltage and output the second sampling voltage. The comparison branch is also used to output the first comparison signal when the second sampling voltage is greater than or equal to the first reference voltage.

3. The overcurrent protection circuit according to claim 1, characterized in that, The sampling branch includes a first resistor; The first resistor is connected between the first ground and the second ground.

4. The overcurrent protection circuit according to claim 1, characterized in that, The comparison branch includes a second resistor, a third resistor, a fourth resistor, and a first comparator; The second resistor and the third resistor are connected in series between the second power supply and the first ground. The connection point between the second resistor and the third resistor is connected to the first input terminal of the first comparator. The fourth resistor is connected between the output terminal and the first input terminal of the first comparator. The second input terminal of the first comparator is connected to the sampling branch.

5. The overcurrent protection circuit according to claim 1, characterized in that, The power output control branch includes a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a first capacitor, a first switching transistor, and a second switching transistor. The fifth resistor, the sixth resistor, and the seventh resistor are connected in series between the comparison branch and the first ground. The connection point between the sixth resistor and the seventh resistor is connected to the first terminal of the first switching transistor. The second terminal of the first switching transistor is connected to the first ground. The eighth resistor is connected between the third terminal of the first switching transistor and the first terminal of the second switching transistor. The ninth resistor is connected between the first power supply and the first terminal of the second switching transistor. The first capacitor and the ninth resistor are connected in parallel. The second terminal of the second switching transistor is connected to the first power supply. The third terminal of the second switching transistor is connected to the electrical equipment.

6. The overcurrent protection circuit according to claim 1, characterized in that, The self-locking branch includes a tenth resistor, an eleventh resistor, and a third switching transistor; The tenth resistor is connected between the second power supply and the first terminal of the third switch transistor. The second terminal of the third switch transistor is connected to the second power supply, and the third terminal of the third switch transistor is connected to the switch branch through the eleventh resistor.

7. The overcurrent protection circuit according to claim 1, characterized in that, The switch branch includes a fourth switch transistor; The first end of the fourth switch is connected to the self-locking branch, the second end of the fourth switch is connected to the first ground, and the third end of the fourth switch is connected to the first end of the comparison branch.

8. The overcurrent protection circuit according to claim 2, characterized in that, The amplification branch includes a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a second capacitor, and a first operational amplifier; The twelfth resistor and the sixteenth resistor are connected in series between the output terminal of the first operational amplifier and the first ground. The connection point between the twelfth resistor and the sixteenth resistor is connected to the second input terminal of the first operational amplifier. The second capacitor is connected between the output terminal of the first operational amplifier and the first ground. The output terminal of the first operational amplifier is connected to the comparator branch. The thirteenth resistor and the fourteenth resistor are connected in series between the second power supply and the second ground. The connection point between the thirteenth resistor and the fourteenth resistor is connected to the first input terminal of the first operational amplifier. The fifteenth resistor is connected between the first input terminal of the first operational amplifier and the first ground.

9. The overcurrent protection circuit according to claim 1, characterized in that, The self-locking recovery branch includes the seventeenth resistor, the eighteenth resistor, the nineteenth resistor, and the fifth switch. The seventeenth resistor and the eighteenth resistor are connected in series between the controller and the first ground. The connection point between the seventeenth resistor and the eighteenth resistor is connected to the first end of the fifth switch transistor. The second end of the fifth switch transistor is connected to the first ground. The third end of the fifth switch transistor is connected to the switch branch. The nineteenth resistor is connected between the second end and the third end of the fifth switch transistor.

10. A power supply device, characterized in that, Includes the overcurrent protection circuit as described in any one of claims 1-9.

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