Overcurrent protection circuit and communication equipment

Abstract

The utility model discloses an over-current protection circuit and communication equipment, and relates to the technical field of over-current protection circuits, and the over-current protection circuit comprises a switching circuit, a detection circuit, a comparison circuit and a reference voltage circuit. The switching circuit is arranged between the first connecting end and the second connecting end; the detection circuit is arranged between the switching circuit and the first connecting end and is used for converting working current flowing through the switching circuit into detection voltage; the comparison circuit is connected with the detection circuit and the switching circuit and is used for comparing detection voltage with reference voltage and controlling the switching circuit to be switched on or switched off according to a comparison result; the reference voltage circuit is connected with the comparison circuit and is used for setting different reference voltages according to different current thresholds and outputting the reference voltages to the comparison circuit. The overcurrent protection circuit provided by the embodiment of the utility model can dynamically adjust and turn off the current threshold of the main loop, dynamically adapt to different working states of the load, and realize overcurrent protection of the main loop.

Description

TECHNICAL FIELD

[0001] The utility model relates to overcurrent protection circuit technical field, especially overcurrent protection circuit and communication equipment. BACKGROUND

[0002] The optical module is an optoelectronic device for photoelectric and electro-optical conversion, and is widely used in communication equipment. In order to ensure the normal operation of the optical module, the communication equipment usually sets an overcurrent protection circuit to prevent the optical module from being damaged after overcurrent.

[0003] The prior art generally uses an overcurrent protection circuit of a comparator, sets a fixed reference voltage based on a current threshold using resistance voltage division, and when the working current in the main loop exceeds the current threshold, the corresponding converted voltage will exceed the reference voltage, and then the comparator outputs a flip level signal to control the main loop to be disconnected. However, this method has the following problems:

[0004] 1. The power consumption of the optical module of the communication equipment changes greatly under different environmental temperatures or working states, and theoretically different current thresholds need to be set. The use of resistance voltage division to set a fixed reference voltage can only correspond to one current threshold, and it is difficult to dynamically adapt to different working states of the optical module.

[0005] 2. When the optical module fails and overcurrent protection occurs, the main loop is disconnected, the current in the loop is zero, and the corresponding converted voltage is also zero. At this time, the comparator will output a level to make the main loop become conductive again, and at this time the optical module fault has not been processed, which will cause overcurrent protection again. Such a cycle repeats, and the main loop is frequently turned on and off, which will cause circuit damage. INVENTION CONTENTS

[0006] The utility model embodiment provides an overcurrent protection circuit and a communication equipment to solve the technical problem that the existing overcurrent protection circuit in the related art can only perform overcurrent protection for one fixed current threshold and cannot dynamically adapt to different working states of the load.

[0007] In a first aspect, an overcurrent protection circuit is provided, comprising:

[0008] A switching circuit is arranged between the first connection end and the second connection end;

[0009] A detection circuit is arranged between the switching circuit and the first connection end, and is used to convert the working current flowing through the switching circuit into a detection voltage;

[0010] A comparison circuit is connected with the detection circuit and the switching circuit, and is used to compare the detection voltage with a reference voltage, and control the switching circuit to be conductive or to be turned off according to the comparison result;

[0011] A reference voltage circuit connected with the comparison circuit, configured to set different reference voltages according to different current threshold values and output the reference voltages to the comparison circuit.

[0012] In some embodiments, the reference voltage circuit comprises a host computer, a master chip, a first resistor and a second resistor.

[0013] A first end of the first resistor and a first end of the second resistor are connected to a power supply, a second end of the first resistor and a second end of the second resistor are connected to two communication interfaces of the host computer and the master chip respectively, and the master chip is configured to convert the current threshold value issued by the host computer into a corresponding reference voltage and output the reference voltage to the comparison circuit.

[0014] In some embodiments, the comparison circuit comprises a first operational amplifier, a third resistor and a fourth resistor, a first end of the third resistor is connected to a digital-to-analog conversion interface of the master chip, a second end of the third resistor is connected to a non-inverting input end of the first operational amplifier, a first end of the fourth resistor is connected to the detection circuit, a second end of the fourth resistor is connected to an inverting input end of the first operational amplifier, and an output end of the first operational amplifier is connected to the switch circuit.

[0015] In some embodiments, the detection circuit comprises a Hall sensor, a first end of the Hall sensor is connected to a first connection end, a second end of the Hall sensor is connected to the switch circuit, and a third end of the Hall sensor is connected to the inverting input end of the first operational amplifier.

[0016] In some embodiments, the switch circuit comprises a transistor, a MOS transistor, a fifth resistor, a sixth resistor and a seventh resistor.

[0017] A first end of the MOS transistor is connected to the second end of the Hall sensor, and a second end of the MOS transistor is connected to a second connection end.

[0018] A first end of the fifth resistor is connected to the first end of the MOS transistor, a second end of the fifth resistor is connected to a third end of the MOS transistor and a first end of the sixth resistor, a second end of the sixth resistor is connected to a first end of the transistor, and a second end of the transistor is grounded.

[0019] A first end of the seventh resistor is connected to the output end of the first operational amplifier, a second end of the seventh resistor is connected to a third end of the transistor, and a second end of the transistor is grounded.

[0020] In some embodiments, the overcurrent protection circuit further comprises:

[0021] An AND gate circuit arranged between the comparison circuit and the switch circuit and connected with the reference voltage circuit.

[0022] In some embodiments, the AND gate circuit comprises an AND gate chip, an eighth resistor and a ninth resistor, a first end of the eighth resistor is connected with an output end of the first operational amplifier, a second end of the eighth resistor is connected with a first input end of the AND gate chip, a second input end of the AND gate chip is connected with the master control chip and a first end of the ninth resistor, an output end of the AND gate chip is connected with a first end of the seventh resistor, and a second end of the ninth resistor is grounded.

[0023] In some embodiments, the overcurrent protection circuit further comprises:

[0024] a delay circuit arranged between the comparison circuit and the AND gate circuit.

[0025] In some embodiments, the delay circuit comprises a second operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor and a first capacitor.

[0026] a first end of the tenth resistor and a first end of the eleventh resistor are connected with a power supply, a second end of the tenth resistor is connected with a first end of the first capacitor, an output end of the first operational amplifier and a non-inverting input end of the second operational amplifier, a second end of the eleventh resistor is connected with an inverting input end of the second operational amplifier and a first end of the twelfth resistor, an output end of the second operational amplifier is connected with a first end of the eighth resistor, a second end of the twelfth resistor is grounded, and a second end of the first capacitor is grounded.

[0027] In a second aspect, a communication device is provided, comprising the overcurrent protection circuit as described above.

[0028] The beneficial effects brought by the technical solutions of the present application include:

[0029] The overcurrent protection circuit and the communication device provided by the embodiments of the present application, the overcurrent protection circuit comprises a switching circuit, a detection circuit, a comparison circuit and a reference voltage circuit, the reference voltage circuit sets different reference voltages according to different current threshold values and outputs the reference voltages to the comparison circuit, the detection circuit converts the working current flowing through the switching circuit into a detection voltage and outputs the detection voltage to the comparison circuit, if the working current of the main loop is greater than the current threshold value, at this time, the detection voltage will be greater than the reference voltage, the comparison circuit further controls the switching circuit to be turned off, so that the main loop is disconnected, and the main loop is protected. That is, the overcurrent protection circuit of the embodiments of the present application can dynamically adjust the current threshold value of the main loop to be turned off, dynamically adapt to different working states of the load, and realize overcurrent protection of the main loop. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings described below are only some of the embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 A principle block diagram of the overcurrent protection circuit provided by the embodiment of the present application is provided.

[0032] Figure 2 A circuit diagram of the overcurrent protection circuit provided by the embodiment of the present application is provided.

[0033] Figure 3 A timing diagram of the overcurrent protection of the overcurrent protection circuit provided by the embodiment of the present application is provided. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0035] The embodiment of the present application provides an overcurrent protection circuit, which can solve the technical problem that the existing overcurrent protection circuit can only perform overcurrent protection on a fixed current threshold, and is difficult to adapt to different working states of the load.

[0036] Referring to Figure 1 The embodiment of the present application provides an overcurrent protection circuit, which includes a switching circuit, a detection circuit, a comparison circuit and a reference voltage circuit.

[0037] The switching circuit is arranged between the first connection end and the second connection end, and the detection circuit is arranged between the switching circuit and the first connection end. The detection circuit is used to convert the working current flowing through the switching circuit into a detection voltage. Specifically, referring to Figure 2 The main loop of the communication device includes the first connection end V1, the detection circuit, the switching circuit and the second connection end V2. The external power supply is connected to the first connection end V1 to supply power for the main loop, and the power-consuming load (such as an optical module) is connected to the second connection end V2 to take power.

[0038] The comparison circuit is connected with the detection circuit and the switch circuit, and is configured to compare the detection voltage with a reference voltage and control the switch circuit to be turned on or turned off according to a comparison result.

[0039] The reference voltage circuit is connected with the comparison circuit, and is configured to set different reference voltages according to different current threshold values and output the reference voltages to the comparison circuit.

[0040] The overcurrent protection circuit in the embodiment of the utility model, it includes switch circuit, detection circuit, comparison circuit and reference voltage circuit, reference voltage circuit sets different reference voltages according to different current threshold values and outputs to comparison circuit, detection circuit converts the working current flowing through switch circuit into detection voltage and outputs to comparison circuit, if the working current of main loop is greater than current threshold value, detection voltage will be greater than reference voltage at this time, comparison circuit further controls switch circuit to be turned off, makes main loop disconnect, protects main loop. That is, the overcurrent protection circuit of the embodiment of the utility model can dynamically adjust the current threshold value of turning off the main loop, dynamically adapt the different working states of the load, and realize the overcurrent protection of the main loop.

[0041] As an optional implementation, in one embodiment of the utility model, as shown in Figure 2 The reference voltage circuit includes a host computer, a master control chip U1, a first resistor R1 and a second resistor R2. The master control chip U1 can be a single-chip microcomputer, has a DAC and a GPIO function, and can respond to an external interrupt signal.

[0042] A first end of the first resistor R1 and a first end of the second resistor R2 are connected to a power supply V+, and a second end of the first resistor R1 and a second end of the second resistor R2 are connected to two communication interfaces of the host computer and the master control chip U1 respectively. The master control chip U1 communicates with the host computer through the communication interfaces, and the communication mode can be I2C, SPI, RS485, RS232, UART, etc. The master control chip U1 is configured to convert the current threshold value issued by the host computer into a corresponding reference voltage and output the reference voltage to the comparison circuit. Specifically, the master control chip U1 can be integrated with a digital-to-analog conversion DAC interface, and the current threshold value (digital signal) issued by the host computer is converted into a corresponding reference voltage (analog signal) and output to the comparison circuit.

[0043] As an optional implementation, in one embodiment of the utility model, as shown in Figure 2As shown, the comparison circuit includes a first operational amplifier U2, a third resistor R3 and a fourth resistor R4, the first end of the third resistor R3 is connected with the digital-analog conversion interface of the master control chip U1, the second end of the third resistor R3 is connected with the non-inverting input terminal of the first operational amplifier U2, the first end of the fourth resistor R4 is connected with the detection circuit, the second end of the fourth resistor R4 is connected with the inverting input terminal of the first operational amplifier U2, and the output terminal of the first operational amplifier U2 is connected with the switch circuit.

[0044] When the voltage (reference voltage) of the non-inverting input terminal of the first operational amplifier U2 is greater than the voltage (detection voltage) of the inverting input terminal, the first operational amplifier U2 outputs a high level to control the switch circuit to be turned on; when the voltage (reference voltage) of the non-inverting input terminal of the first operational amplifier U2 is less than the voltage (detection voltage) of the inverting input terminal, the first operational amplifier U2 outputs a low level to control the switch circuit to be turned off. In addition, the output terminal of the first operational amplifier U2 is connected with the master control chip U1 (GPIO0), and the master control chip U1 reports the over-current protection event to the upper computer after receiving the falling edge of the low level output by the first operational amplifier U2.

[0045] As an optional implementation, in one utility model embodiment, referring to Figure 2 As shown, the detection circuit includes a Hall sensor U3, the first end of the Hall sensor U3 is connected with the first connection end, the second end of the Hall sensor U3 is connected with the switch circuit, and the third end (output terminal) of the Hall sensor U3 is connected with the inverting input terminal of the first operational amplifier U2. The Hall current sensor is connected in series in the main circuit, and linearly converts the working current in the main circuit into a corresponding detection voltage output to the inverting input terminal of the second operational amplifier U2. In addition, the detection circuit can also be built by using elements such as current sensing amplifiers.

[0046] As an optional implementation, in one utility model embodiment, referring to Figure 2 As shown, the switch circuit includes a triode Q1, a MOS tube M1, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7. The triode Q1 is an NPN triode, and the MOS tube M1 is a PMOS tube. The MOS tube M1 can also be replaced by elements such as IGBT.

[0047] The first end (drain) of the MOS tube M1 is connected with the second end of the Hall sensor U3, and the second end (source) of the MOS tube M1 is connected with the second connection end V2.

[0048] The first end of the fifth resistor R5 is connected with the first end of the MOS tube M1, the second end of the fifth resistor R5 is connected with the third end (gate) of the MOS tube M1 and the first end of the sixth resistor R6. The second end of the sixth resistor R6 is connected with the first end (collector) of the triode Q1.

[0049] The first end of the seventh resistor R7 is connected with the output end of the first operational amplifier U2, the second end of the seventh resistor R7 is connected with the third end (base) of the triode Q1, and the second end (emitter) of the triode Q1 is grounded.

[0050] When the first end of the seventh resistor R7 inputs low level, the triode Q1 is cut off, the first end (drain) and the third end (gate) of the MOS tube M1 are equal in voltage, the MOS tube M1 is in the cut-off state, and the main circuit is disconnected; when the first end of the seventh resistor R7 inputs high level, the triode Q1 is turned on, the third end (gate) of the MOS tube M1 is grounded through the sixth resistor R6, so that the MOS tube M1 is in the on state, and the main circuit is turned on.

[0051] As an optional embodiment, in one utility model embodiment, referring to Figure 2 As shown in the figure, the overcurrent protection circuit further comprises an AND gate circuit arranged between the comparison circuit and the switch circuit and connected with the reference voltage circuit.

[0052] Further, the AND gate circuit comprises an AND gate chip U5, an eighth resistor R8 and a ninth resistor R9. The first end of the eighth resistor R8 is connected with the output end of the second operational amplifier U4, the second end of the eighth resistor R8 is connected with the first input end of the AND gate chip U5, the second input end of the AND gate chip U5 is connected with the main control chip U1 and the first end of the ninth resistor R9, the output end of the AND gate chip U5 is connected with the first end of the seventh resistor, and the second end of the ninth resistor R9 is grounded.

[0053] The AND gate chip U5 is a logic gate chip with two inputs, the second input end of the AND gate chip U5 is pulled down to the ground through the ninth resistor R9, and the AND gate chip U5 outputs low level by default when powered on, so that the switch circuit is in the disconnected state. Only when the main control chip U1 (GPIO1 interface) and the second operational amplifier U4 both output high level, the AND gate chip U2 outputs high level to control the switch circuit to be turned on, so that the main circuit is in the on state.

[0054] When the load fails to cause the working current to be greater than the current threshold, the comparison circuit outputs a low level signal to trigger the reference voltage circuit and the delay circuit at the same time, the delay circuit outputs a low level to the first input end of the AND gate chip U5, the AND gate chip U5 outputs a control low level to turn off the switch circuit, the main circuit is disconnected, and the load is protected; after the main control chip of the reference voltage circuit receives the low level signal of the comparison circuit, the main control chip outputs a low level to the second input end of the AND gate chip U5, so that the AND gate chip U5 keeps low level output, and the switch circuit keeps in the disconnected state. After the load fails, the switch circuit of the main circuit is in the off state, so as to avoid the case that the circuit is damaged due to the frequent switching of the main circuit while the load failure is not processed. In addition, the AND gate circuit can also be built with a triode or a diode.

[0055] As an optional implementation, in one utility model embodiment, referring to Figure 2 As shown in the figure, the overcurrent protection circuit further comprises: a delay circuit, which is arranged between the comparison circuit and the switch circuit. The main function of the delay circuit is to output a stable state (high level) in normal state, and when a trigger signal is input at the input end, the output end outputs an unstable state (low level), and after a certain time, the output end returns to the output in normal state. The delay circuit can provide sufficient time for the main control chip of the reference voltage circuit to output a low level to the second input end of the AND gate chip U5 after receiving the low level signal from the comparison circuit.

[0056] Further, the delay circuit comprises a second operational amplifier U4, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12 and a first capacitor C1. The first end of the tenth resistor R10 and the first end of the eleventh resistor R11 are connected to the power supply V+, the second end of the tenth resistor R10 is connected to the first end of the first capacitor C1, the output end of the first operational amplifier U2 and the non-inverting input end of the second operational amplifier U4, the second end of the eleventh resistor R11 is connected to the inverting input end of the second operational amplifier U4 and the first end of the twelfth resistor R12, the output end of the second operational amplifier U4 is connected to the first end of the eighth resistor R8, and the second end of the twelfth resistor R12 is grounded.

[0057] The eleventh resistor R11 and the twelfth resistor R12 constitute a voltage divider circuit to provide a bias voltage for the inverting negative input end of the second operational amplifier U4. In normal state, the first capacitor C1 is fully charged, the voltage at the non-inverting input end of the second operational amplifier U4 is equal to the voltage of the power supply V+, and the second operational amplifier U4 outputs a high level. When the non-inverting input voltage becomes low (the output end of the first operational amplifier U2), the first capacitor C1 is quickly discharged, so that the non-inverting input level of the second operational amplifier U4 is reduced to low level, and the inverting input level of the second operational amplifier U4 is greater than the non-inverting input level, so that the second operational amplifier U4 outputs a low level. When the non-inverting input voltage becomes high, the power supply V+ charges the first capacitor C1 through the tenth resistor R10, and when the charging voltage on the first capacitor C1 is greater than the inverting input voltage of the second operational amplifier U4, the second operational amplifier U4 outputs a high level again, thereby ending a single-shot trigger. By changing the voltage division of the eleventh resistor R11 and the twelfth resistor R12 or adjusting the values of the tenth resistor R10 and the first capacitor C1, the delay time of the delay circuit can be adjusted. In addition, the delay circuit can also be built with a time relay or a 555 chip.

[0058] The overcurrent protection circuit in the utility model embodiment has the following specific working modes:

[0059] When power is on, the host computer of the reference voltage circuit sets an overcurrent protection current threshold, and sends it to the main control chip of the reference voltage circuit through a communication interface, and the main control chip of the reference voltage circuit outputs a reference voltage to the comparison circuit according to a conversion formula, and the main control chip of the reference voltage circuit outputs a high level to the AND gate circuit, so that the main loop is turned on to supply power to the load.

[0060] During power supply, the detection circuit converts the working current in the main loop into a corresponding detection voltage, and the detection voltage is output to the inverting input terminal of the first operational amplifier of the comparison circuit. When the load fails and the working current is greater than the current threshold, the corresponding detection voltage will be greater than the reference voltage, resulting in that the comparison circuit outputs a low level, so that the delay circuit outputs a low level to the AND gate circuit, and the AND gate circuit outputs a low level to control the switch circuit to disconnect the main loop, so that the main loop stops supplying power to the load, thereby protecting the load. Meanwhile, the falling edge formed by the low level output by the comparison circuit triggers the overcurrent response function of the main control chip, and the main control chip of the reference voltage circuit outputs a low level to the AND gate circuit. After the main loop is disconnected, the current in the main loop is zero, the comparison circuit outputs a high level again, and the delay circuit also outputs a high level after the delay time ends. The overcurrent response function of the main control chip outputs a low level to the second input terminal of the AND gate chip of the AND gate circuit before this time, so that the AND gate circuit maintains a low level state, and the switch circuit is in a disconnected state, thereby avoiding that the main loop enters a cycle state of turning on-disconnecting-turning on before the fault is processed, and further protecting the load.

[0061] Further, Figure 3 The timing diagram for overcurrent protection of the overcurrent protection circuit in the embodiment of the utility model is shown as follows: Figure 3

[0062] At t0, the load fails, the working current is greater than the current threshold, the inverting input terminal of the first operational amplifier of the comparison circuit is greater than the same-phase input terminal, the comparison circuit outputs a low level, the delay circuit also outputs a low level, and the AND gate circuit also outputs a low level at this time, so that the switch circuit becomes a disconnected state, the main loop is disconnected, and the load is protected.

[0063] At t1, after the main loop is disconnected, the current in the main loop is zero, the comparison circuit outputs a high level again, but the output of the delay circuit is still a low level, the AND gate circuit also outputs a low level at this time, the switch circuit remains in a disconnected state, and the main loop remains in a disconnected state.

[0064] ​At t2, the main control chip of the reference voltage circuit receives the falling edge trigger event of the low level output by the comparison circuit at t0, and outputs a low level to the second input end of the AND gate chip of the AND gate circuit.

[0065] At t3, the delay time of the delay circuit ends, and the delay circuit returns to a high level, but at this time, the main control chip has output a low level to the second input end of the AND gate chip, so the AND gate chip still outputs a low level, and the switch circuit remains in an open state, and the main circuit remains in an open state.

[0066] As can be seen from the above timing, the overcurrent protection circuit in the embodiment of the utility model can immediately disconnect the main circuit when the load fails, plays a role in protecting the load, and triggers the overcurrent response function of the main control chip of the reference voltage circuit, actively outputs a low level, avoids the main circuit from entering a cycle state of conduction-disconnection-conduction before the fault is cleared, and further protects the load.

[0067] In addition, the embodiment of the utility model also provides the second capacitor C2 to the seventh capacitor C7, which can play a role in voltage stabilization and filtering at the corresponding positions.

[0068] The embodiment of the utility model also provides a communication device comprising the overcurrent protection circuit.

[0069] In the description of the utility model, it should be pointed out that the position or location relationship indicated by the terms "upper", "lower" and the like is based on the position or location relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element indicated must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. Unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated connection, it can be mechanical connection, or electrical connection, it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0070] It should be noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one from another entity or action, without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0071] The above description is merely that of the specific embodiments of the present application, and enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An overcurrent protection circuit, characterized by comprising: The overcurrent protection circuit comprises: a switch circuit arranged between the first connection end and the second connection end; a detection circuit arranged between the switch circuit and the first connection end, configured to convert working current flowing through the switch circuit into a detection voltage; a comparison circuit connected with the detection circuit and the switch circuit, configured to compare the detection voltage with a reference voltage and control the switch circuit to be turned on or turned off according to a comparison result; a reference voltage circuit connected with the comparison circuit, configured to set different reference voltages according to different current threshold values and output the reference voltages to the comparison circuit.

2. The overcurrent protection circuit according to claim 1, wherein: the reference voltage circuit comprises a host computer, a master control chip, a first resistor and a second resistor; a first end of the first resistor and a first end of the second resistor are connected with a power supply, a second end of the first resistor and a second end of the second resistor are respectively connected with two communication interfaces of the host computer and the master control chip, and the master control chip is configured to convert a current threshold value issued by the host computer into a corresponding reference voltage and output the reference voltage to the comparison circuit.

3. The overcurrent protection circuit according to claim 2, wherein: the comparison circuit comprises a first operational amplifier, a third resistor and a fourth resistor, a first end of the third resistor is connected with a digital-to-analog conversion interface of the master control chip, a second end of the third resistor is connected with a non-inverting input end of the first operational amplifier, a first end of the fourth resistor is connected with the detection circuit, a second end of the fourth resistor is connected with an inverting input end of the first operational amplifier, and an output end of the first operational amplifier is connected with the switch circuit.

4. The overcurrent protection circuit according to claim 3, wherein: the detection circuit comprises a Hall sensor, a first end of the Hall sensor is connected with the first connection end, a second end of the Hall sensor is connected with the switch circuit, and a third end of the Hall sensor is connected with the inverting input end of the first operational amplifier.

5. The overcurrent protection circuit according to claim 4, wherein: the switch circuit comprises a triode, a MOS tube, a fifth resistor, a sixth resistor and a seventh resistor; a first end of the MOS tube is connected with the second end of the Hall sensor, and a second end of the MOS tube is connected with the second connection end; a first end of the fifth resistor is connected with the first end of the MOS tube, a second end of the fifth resistor is connected with a third end of the MOS tube and a first end of the sixth resistor, a second end of the sixth resistor is connected with a first end of the triode; a first end of the seventh resistor is connected with the output end of the first operational amplifier, a second end of the seventh resistor is connected with a third end of the triode, and a second end of the triode is grounded.

6. The overcurrent protection circuit of claim 5, wherein, The overcurrent protection circuit further comprises: an AND gate circuit arranged between the comparison circuit and the switch circuit and connected with the reference voltage circuit.

7. The overcurrent protection circuit according to claim 6, wherein: The AND gate circuit comprises an AND gate chip, an eighth resistor and a ninth resistor, a first end of the eighth resistor is connected with an output end of the first operational amplifier, a second end of the eighth resistor is connected with a first input end of the AND gate chip, a second input end of the AND gate chip is connected with the master control chip and a first end of the ninth resistor, an output end of the AND gate chip is connected with a first end of the seventh resistor, and a second end of the ninth resistor is grounded.

8. The overcurrent protection circuit of claim 7, wherein, Further comprising: a delay circuit arranged between the comparison circuit and the AND gate circuit.

9. The overcurrent protection circuit according to claim 8, characterized in that: the delay circuit comprises a second operational amplifier, a tenth resistor, an eleventh resistor, a twelfth resistor and a first capacitor; a first end of the tenth resistor and a first end of the eleventh resistor are connected with a power supply, a second end of the tenth resistor is connected with a first end of the first capacitor, an output end of the first operational amplifier and a non-inverting input end of the second operational amplifier, a second end of the eleventh resistor is connected with an inverting input end of the second operational amplifier and a first end of the twelfth resistor, an output end of the second operational amplifier is connected with a first end of the eighth resistor, a second end of the twelfth resistor is grounded, and a second end of the first capacitor is grounded.

10. A communication device, characterized by comprise the overcurrent protection circuit according to any one of claims 1-9.

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