An overcurrent protection circuit and intelligent power distribution device

Abstract

The utility model discloses a kind of overcurrent protection circuit and intelligent power distribution unit, comprising: current detection module, switch module, control module and at least one first suppression element;The output end of power supply is connected to the first end of current detection module, the first end of switch module is connected to the second end of current detection module, the input end of control module is connected to the output end of current detection module, and current detection module is used to collect the output current of power supply;The second end of switch module is connected to load, and the output end of control module is connected to the control end of switch module, control module is configured to when output current is greater than set threshold, control switch module is turned off;Wherein, first suppression element is connected to the first end and the second end of switch module, for when switch module is turned off, overvoltage pulse generated by the second end of switch module is inhibited.The utility model can solve the problem that switch module is damaged due to overvoltage pulse generated by inductive load when overcurrent is turned off.

Description

Technical Field

[0001] This utility model relates to the field of automotive power network management technology, and in particular to an overcurrent protection circuit and an intelligent power distribution device. Background Technology

[0002] In the power distribution circuit of an onboard intelligent power distribution device, the switching module, as the core component controlling the connection and disconnection between the main power network and the load, is crucial to the safety of the vehicle's power network. When an overcurrent fault occurs in the load, the control module must quickly control the switching module to shut down based on feedback from the current detection module, in order to isolate the faulty load and protect other devices in the main power network.

[0003] However, in automotive applications, the output of a switching module is often connected to an inductive load (such as electrical equipment or wiring harnesses). Due to the inherent limitation of inductor current, when the switching module is turned off, the inductive load will generate an overvoltage pulse across its terminals due to the lack of a freewheeling circuit. This is especially problematic during rapid turn-off at high currents (e.g., 200A), where the overvoltage pulse can create an extremely low negative voltage on the load side. If the switching module has limited voltage withstand capability, this negative voltage, combined with the power supply voltage, can easily cause the voltage across the switching module to exceed its maximum withstand value, damaging the module and resulting in the loss of overcurrent protection. This negatively impacts the reliability of the intelligent power distribution device and the safety of the vehicle's power network. Utility Model Content

[0004] This invention provides an overcurrent protection circuit and an intelligent power distribution device to solve the problem of damage to the switching module caused by overvoltage pulses generated by the inductive load when the switch is turned off due to overcurrent.

[0005] In a first aspect, this utility model provides an overcurrent protection circuit, comprising: a current detection module, a switching module, a control module, and at least one first suppression element; a first end of the current detection module is connected to the output end of a power supply, a second end of the current detection module is connected to the first end of the switching module, and the output end of the current detection module is connected to the input end of the control module, wherein the current detection module is used to collect the output current of the power supply; a second end of the switching module is connected to a load, and the control end of the switching module is connected to the output end of the control module, wherein the control module is configured to control the switching module to turn off when the output current is greater than a set threshold; wherein the first suppression element is connected in parallel to the first end and the second end of the switching module, and is used to suppress the overvoltage pulse generated at the second end of the switching module when the switching module is turned off.

[0006] Optionally, the first suppression element includes a first transient suppression diode, which is connected in parallel to the first and second terminals of the switching module.

[0007] Optionally, the overcurrent protection circuit further includes at least one second suppression element; the first end of the second suppression element is connected to the second end of the switching module, the second end of the second suppression element is connected to a reference ground, and the second suppression element is used to suppress the overvoltage pulse generated at the second end of the switching module when the switching module is turned off.

[0008] Optionally, the second suppression element includes a second transient suppression diode, with the first end of the second transient suppression diode serving as the first end of the second suppression element, and the second end of the second transient suppression diode serving as the second end of the second suppression element.

[0009] Optionally, the switching module includes a first switching unit and a second switching unit, both having a first terminal, a second terminal, and a control terminal; the control module includes a microcontroller chip, which has a first output pin and a second output pin, which serve as the output terminals of the control module; the control terminal of the first switching unit is connected to the first output pin, the first terminal of the first switching unit serves as the first terminal of the switching module, and the second terminal of the first switching unit is connected to the second terminal of the second switching unit; the control terminal of the second switching unit is connected to the second output pin, and the first terminal of the second switching unit serves as the second terminal of the switching module.

[0010] Optionally, the switching module includes a first MOSFET and a second MOSFET; both the first MOSFET and the second MOSFET include a gate, a source, and a drain; the control module includes a microcontroller chip, which has a first output pin and a second output pin, which serve as the output terminals of the control module; the gate of the first MOSFET is connected to the first output pin, the source of the first MOSFET serves as the first terminal of the switching module, and the drain of the first MOSFET is connected to the drain of the second MOSFET; the gate of the second MOSFET is connected to the second output pin, and the source of the second MOSFET serves as the second terminal of the switching module.

[0011] Optionally, the overcurrent protection circuit also includes a drive module. The input terminal of the drive module is connected to the output terminal of the control module, and the output terminal of the drive module is connected to the control terminal of the switch module. The drive module is used to amplify the signal output by the control module.

[0012] Optionally, the current detection module includes a sensing resistor and an operational amplifier; the operational amplifier has a first input terminal, a second input terminal, and an output terminal; the first terminal of the sensing resistor serves as the first terminal of the current detection module, and the second terminal of the sensing resistor serves as the second terminal of the current detection module; the first input terminal of the operational amplifier is connected to the first terminal of the sensing resistor, the second input terminal of the operational amplifier is connected to the second terminal of the sensing resistor, and the output terminal of the operational amplifier serves as the output terminal of the current detection module.

[0013] Optionally, the load is an inductive load.

[0014] Secondly, this utility model provides an intelligent power distribution device, including the overcurrent protection circuit provided in any embodiment of this utility model.

[0015] The overcurrent protection circuit provided in this embodiment of the utility model collects the output current of the power supply through a current detection module and converts the output current into a voltage signal. When the output current is greater than a set threshold, the control module controls the switch module to turn off. The overcurrent protection of the load is achieved through hardware structure, which is low in cost and fast in response. In addition, by connecting the first suppression element in parallel to the first and second terminals of the switch module, the overvoltage pulse generated by the inductive load when the switch module is turned off is effectively suppressed, avoiding damage to the switch module due to overvoltage. This solves the problem of easy damage to the switching device in traditional overcurrent protection circuits.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of an overcurrent protection circuit provided in an embodiment of the present invention;

[0019] Figure 2 The provided diagram is a schematic diagram of the structure of the first suppression element in one embodiment;

[0020] Figure 3 This is a schematic diagram of another overcurrent protection circuit provided in this embodiment of the utility model;

[0021] Figure 4 The provided diagram is a schematic diagram of the structure of the second suppression element in one embodiment;

[0022] Figure 5 The provided diagram is a structural schematic of a switch module in one embodiment;

[0023] Figure 6 This is a schematic diagram of the switch module in yet another embodiment;

[0024] Figure 7 This is a schematic diagram of another overcurrent protection circuit provided in this embodiment of the utility model;

[0025] Figure 8 The provided diagram is a structural schematic of a current detection module in one embodiment;

[0026] Figure 9 This is a schematic diagram of another overcurrent protection circuit provided in an embodiment of the present invention;

[0027] Figure 10 It shows the voltage waveform and output current waveform of the overcurrent protection circuit to ground when the switching module is turned off.

[0028] Figure 11 It shows the voltage difference waveform between the first and second terminals of the switching module and the output current waveform when the switching module is turned off.

[0029] Figure 12 The waveforms of the overcurrent protection circuit output to ground and the current waveform after adding the first transient suppression diode and the second transient suppression diode are shown.

[0030] Figure 13 The waveforms of the voltage difference and current at the first and second terminals of the switching module are obtained after adding the first transient suppression diode and the second transient suppression diode. Detailed Implementation

[0031] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0032] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0033] Figure 1 This is a schematic diagram of an overcurrent protection circuit provided in an embodiment of this utility model. Figure 1 As shown, the overcurrent protection circuit 1 includes a current detection module 11, a switching module 12, a control module 13, and at least one first suppression element 14.

[0034] The first end of the current detection module 11 is connected to the output end of the power supply 10, the second end of the current detection module 11 is connected to the first end of the switch module 12, and the output end of the current detection module 11 is connected to the input end of the control module 13. The current detection module 11 is used to collect the output current of the power supply 10.

[0035] The second terminal of the switch module 12 is connected to the load 20, and the control terminal of the switch module 12 is connected to the output terminal of the control module 13. The control module 13 is configured to control the switch module 12 to turn off when the output current is greater than a set threshold. The first suppression element 14 is connected in parallel to the first and second terminals of the switch module 12 and is used to suppress the overvoltage pulse generated at the second terminal of the switch module 12 when the switch module 12 is turned off.

[0036] Specifically, the current detection module 11 is used to collect the output current of the power supply 10 in real time and convert the current signal into a voltage signal that can be recognized by the control module 13.

[0037] Switching module 12 refers to a switch that can be controlled to open or close via an electrical signal. Switching module 12 can be a unidirectional switch, such as a switch consisting of a bidirectional switch and a diode connected in series, capable of unidirectional conduction, or a bidirectional switch, such as a metal-oxide-semiconductor field-effect transistor (MOSFET) or an insulated-gate bipolar transistor (IGBT) with an anti-parallel freewheeling diode. It is understood that the specific type of switching module 12 can be selected and configured according to actual application scenarios, and this invention does not limit its application.

[0038] The control module 13 may include a microcontroller. Optionally, the control module 13 may include a microcontroller, or a digital signal processor (DSP) or a field-programmable gate array (FPGA).

[0039] The first suppression element 14 is an overvoltage protection device connected in parallel to the first and second terminals of the switching module 12. For example, the first suppression element 14 can be a transient voltage suppressor (TVS) diode, used to suppress the overvoltage pulse generated at its second terminal when the switching module 12 is turned off.

[0040] It should be noted that the number of first suppression elements 14 can be set according to the magnitude of the output current of the power supply 10. If the output current of the power supply 10 is large, multiple first suppression elements 14 can be connected in parallel.

[0041] Continue to refer to Figure 1 The operation of the overcurrent protection circuit 1 is as follows:

[0042] Normal operating condition: The output current of power supply 10 flows to switch module 12 via current detection module 11. Switch module 12 is in the conducting state under the control of control module 13, and the current flows to load 20 (such as vehicle inductive load, wiring harness, etc.) through switch module 12. Current detection module 11 collects the output current of power supply 10 in real time and converts it into a voltage signal, which is transmitted to control module 13. Control module 13 determines that the output current is less than a set threshold and keeps switch module 12 conducting. Under normal operating condition, the first suppression element 14 is in the cutoff state and does not affect the normal operation of the circuit.

[0043] Overcurrent protection status: When the current detection module 11 detects that the output current of the power supply 10 exceeds the set threshold, the control module 13 determines that the output current is greater than the set threshold through the amplified voltage signal, and immediately outputs a shutdown control signal to control the switch module 12 to turn off, disconnecting the power supply 10 from the load 20. At the moment the switch module 12 turns off, because the load 20 is an inductive load, the inductor current cannot change abruptly. If there is no protection, an extremely high overvoltage pulse will be generated on the load side, which, when superimposed with the power supply voltage, may exceed the maximum withstand voltage of the switch module 12, causing it to be damaged. At this time, the first suppression element 14 conducts because the voltage across its terminals exceeds its breakdown voltage, clamping the overvoltage pulse within a safe threshold, ensuring that the voltage difference between the first and second terminals of the switch module 12 does not exceed its maximum withstand voltage, and preventing the switch module 12 from being damaged due to the voltage between the first and second terminals exceeding the maximum withstand voltage.

[0044] The overcurrent protection circuit provided in this embodiment of the utility model collects the output current of the power supply through the current detection module 11 and converts the output current into a voltage signal. When the output current is greater than a set threshold, the control module 13 controls the switch module 12 to turn off. The overcurrent protection of the load is achieved through hardware structure, which is low in cost and fast in response. In addition, by connecting the first suppression element 14 in parallel to the first and second terminals of the switch module 12, the overvoltage pulse generated by the inductive load when the switch module 12 is turned off is effectively suppressed, and the switch module 12 is prevented from being damaged by overvoltage. This solves the problem of easy damage to the switching device in the traditional overcurrent protection circuit 1.

[0045] Figure 2 This provides a schematic diagram of the structure of the first suppression element in one embodiment. For example... Figure 2As shown, the first suppression element 14 includes a first transient suppression diode TVS1, which is connected in parallel to the first and second terminals of the switching module 12.

[0046] Specifically, the first transient voltage suppressor diode, TVS1, is a bidirectional TVS, which is equivalent to two avalanche diodes with opposite polarities connected in series. When a forward or reverse transient overvoltage occurs in the circuit, the corresponding avalanche diode will undergo avalanche breakdown, changing the impedance between its terminals from high to low, thereby absorbing the instantaneous large current. After avalanche breakdown, the bidirectional TVS can clamp the voltage across its terminals to a predetermined value, ensuring that the voltage across the protected circuit components does not exceed their withstand voltage limit, thus protecting the circuit components from the impact of transient high-voltage spike pulses.

[0047] Based on the reverse breakdown characteristic of the bidirectional TVS, when the switching module 12 is turned off due to overcurrent, the inductive load will generate an overvoltage pulse because the inductor current cannot change abruptly. At this time, the voltage across the bidirectional TVS exceeds its breakdown voltage, and it will quickly turn on, clamping the overvoltage pulse within a safe threshold. It dissipates the overvoltage energy through its own shunt, preventing the voltage difference between the first and second terminals of the switching module 12 from exceeding its maximum withstand voltage and causing damage.

[0048] Figure 3 This is a schematic diagram of another overcurrent protection circuit provided in this embodiment of the utility model. Figure 3 As shown, the overcurrent protection circuit 1 further includes at least one second suppression element 15; the first end of the second suppression element 15 is connected to the second end of the switching module 12, and the second end of the second suppression element 15 is connected to the reference ground. The second suppression element 15 is used to suppress the overvoltage pulse generated at the second end of the switching module 12 when the switching module 12 is turned off.

[0049] Specifically, when the switch module 12 is turned off by the control module 13 due to overcurrent, if the load is inductive, an overvoltage pulse will be generated on the load side (i.e., the second terminal of the switch module 12) due to the characteristic that the inductor current cannot change abruptly. At this time, the voltage across the second suppression element 15 exceeds its breakdown voltage, and it will quickly conduct, clamping the overvoltage pulse between the second terminal of the switch module 12 and the reference ground within a safe range. It dissipates the overvoltage energy through its own shunt, directly suppressing the overvoltage surge on the load side. The overvoltage pulse design of the second suppression element 15 supplements the protection range of the first suppression element 14, forming a dual protection of "protection of the first and second terminals of the switch module + protection of the load side to ground", more accurately suppressing the negative voltage surge when the inductive load is turned off.

[0050] Figure 4 This provides a schematic diagram of the structure of the second suppression element in one embodiment. For example... Figure 4As shown, the second suppression element 15 includes a second transient suppression diode TVS2. The first terminal of the second transient suppression diode TVS2 serves as the first terminal of the second suppression element 15, and the second terminal of the second transient suppression diode TVS2 serves as the second terminal of the second suppression element 15. The second transient suppression diode TVS2 is a bidirectional TVS.

[0051] Figure 5 This provides a structural schematic diagram of a switch module in one embodiment. For example... Figure 5 As shown, the switch module 12 includes a first switch unit 121 and a second switch unit 122. Both the first switch unit 121 and the second switch unit 122 have a first terminal, a second terminal, and a control terminal. The control module 13 includes a microcontroller chip. The microcontroller chip has a first output pin and a second output pin. The first output pin and the second output pin of the microcontroller chip serve as the output terminals of the control module 13.

[0052] The control terminal of the first switch unit 121 is connected to the first output pin, and the first end of the first switch unit 121 serves as the first end of the switch module 12. The second end of the first switch unit 121 is connected to the second end of the second switch unit 122. The control terminal of the second switch unit 122 is connected to the second output pin, and the first end of the second switch unit 122 serves as the second end of the switch module 12.

[0053] Specifically, the first switching unit 121 and the second switching unit 122 can be a transistor, a triode, or a thyristor.

[0054] The control module 13 sends a conduction control signal (such as a high level) to the control terminals of the first switch unit 121 and the second switch unit 122 through the first output pin and the second output pin, and both switch units are in the conduction state; the output current of the power supply 10 flows to the load 20 through the current detection module 11, the first switch unit 121, and the second switch unit 122. The current detection module 11 collects the current in real time and transmits it to the control module 13. The control module 13 determines that the output current of the power supply 10 is less than the set threshold and keeps the first switch unit 121 and the second switch unit 122 in conduction.

[0055] When the control module 13 determines that the output current of the power supply 10 is greater than the set threshold, the control module 13 sends a shutdown control signal (such as a low level) to the control terminals of the two switching units through the first output pin and the second output pin, so that the first switching unit 121 and the second switching unit 122 are turned off at the same time, cutting off the connection between the power supply 10 and the load 20; at the moment of shutdown, the overvoltage pulse generated by the inductive load is jointly suppressed by the first suppression element 14 and the second suppression element 15, so as to avoid the first switching unit 121 and the second switching unit 122 being damaged due to overvoltage.

[0056] Figure 6This is a schematic diagram of the switch module in another embodiment. For example... Figure 6 As shown, optionally, the switching module includes a first MOSFET M1 and a second MOSFET M2; both the first MOSFET M1 and the second MOSFET M2 include a gate, a source, and a drain; the control module 13 includes a microcontroller chip, which has a first output pin and a second output pin, which serve as the output terminals of the control module 13; the gate of the first MOSFET M1 is connected to the first output pin, the source of the first MOSFET M1 serves as the first terminal of the switching module 12, and the drain of the first MOSFET M1 is connected to the drain of the second MOSFET M2; the gate of the second MOSFET M2 is connected to the second output pin, and the source of the second MOSFET M2 serves as the second terminal of the switching module 12.

[0057] It should be noted that the first MOSFET M1 has a first freewheeling diode D1, and the second MOSFET M2 has a second freewheeling diode D2. The anode of the first freewheeling diode D1 is connected to the source of the first MOSFET M1, and the cathode of the first freewheeling diode D1 is connected to the drain of the first MOSFET M1. The anode of the second freewheeling diode D2 is connected to the source of the second MOSFET M2, and the cathode of the second freewheeling diode D2 is connected to the drain of the second MOSFET M2. This configuration can suppress reverse electromotive force, protect the MOSFETs, and improve the reliability and lifespan of the switching module 12.

[0058] When the control module 13 determines that the output current of the power supply 10 exceeds the set threshold, the control module 13 sends a shutdown control signal to the gates of the first MOSFET M1 and the second MOSFET M2. The first MOSFET M1 and the second MOSFET M2 are simultaneously turned off, cutting off the current path between the power supply 10 and the load 20. At this time, the load cannot generate a reverse electromotive force due to the inductor current not changing abruptly, forming a negative voltage surge. When the inductive load generates a reverse electromotive force, the first freewheeling diode D1 and the second freewheeling diode D2 conduct due to the polarity of the reverse electromotive force, providing a freewheeling circuit for the inductor current.

[0059] Figure 7 This is a schematic diagram of another overcurrent protection circuit provided in this embodiment of the utility model. Figure 7 As shown, optionally, the overcurrent protection circuit 1 also includes a drive module 16. The input terminal of the drive module 16 is connected to the output terminal of the control module 13, and the output terminal of the drive module 16 is connected to the control terminal of the switch module 12. The drive module 16 is used to amplify the signal output by the control module 13.

[0060] Specifically, the control signal output by the control module 13 has a problem of "insufficient power," such as low voltage and current, which cannot directly drive the switch module 12 to work normally. At this time, the role of the drive module 16 is to amplify the control signal to give it sufficient power, thereby effectively controlling the on / off state of the switch module 12.

[0061] For example, suppose the signal output by the control module 13 is a weak 5V, 1mA signal, while the switch module requires a 12V, 100mA signal to trigger its action. The drive module 16 converts the 5V / 1mA signal to 12V / 100mA, ensuring that the switch module 12 can accurately execute the instructions of the control module, thereby ensuring the reliability of the overcurrent protection circuit 1.

[0062] Figure 8 This provides a schematic diagram of the current detection module in one embodiment. For example... Figure 8 As shown, the current detection module 11 includes a detection resistor R1 and an operational amplifier U1; the operational amplifier U1 has a first input terminal, a second input terminal, and an output terminal.

[0063] The first end of the sensing resistor R1 serves as the first end of the current sensing module 11, and the second end of the sensing resistor R1 serves as the second end of the current sensing module 11.

[0064] The first input terminal of the operational amplifier U1 is connected to the first terminal of the detection resistor R1, the second input terminal of the operational amplifier U1 is connected to the second terminal of the detection resistor R1, and the output terminal of the operational amplifier U1 serves as the output terminal of the current detection module 11.

[0065] Specifically, when current flows through the circuit, a voltage difference is generated across the sensing resistor R1. Operational amplifier U1 captures this voltage difference through its two input terminals, amplifies it internally, and outputs a voltage signal that is directly proportional to the voltage difference (i.e., the circuit current). Control module 13 can use this voltage signal to determine the magnitude of the current in the circuit, providing a basis for overcurrent protection and other functions.

[0066] Figure 9 This is a schematic diagram of another overcurrent protection circuit provided in this embodiment of the utility model. Figure 9 As shown, the overcurrent protection circuit 1 includes a current detection module 11, a switching module 12, a control module 13, and at least one first suppression element 14.

[0067] Optionally, the current detection module 11 includes a detection resistor R1 and an operational amplifier U1; the switching module 12 includes a first MOSFET M1 and a second MOSFET M2; the first suppression element 14 includes a first transient suppression diode TVS1. The overcurrent protection circuit 1 further includes at least one second suppression element 15, which includes a second transient suppression diode TVS2. Optionally, the overcurrent protection circuit 1 further includes a drive module 16.

[0068] Specifically, the detection resistor R1 converts the current signal into a voltage signal, which is then amplified and output by the operational amplifier U1. The control module 13 determines whether the output current of the power supply 10 is greater than a set threshold based on the voltage signal. If the output current of the power supply 10 is less than the set threshold, it outputs a turn-on control signal to turn on the first MOSFET M1 and the second MOSFET M2. At this time, the first transient suppression diode TVS1 and the second transient suppression diode TVS2 are inactive.

[0069] When the control module 13 determines that the output current of the power supply 10 is greater than the set threshold based on the voltage signal, it outputs a shutdown control signal to control the first MOSFET M1 and the second MOSFET M2 to turn off, disconnecting the power supply 10 from the load 20. At the moment of shutdown, because the load 20 is an inductive load, the inductor current cannot change abruptly. Without protection, an extremely high overvoltage pulse will be generated on the load side, which, when superimposed with the power supply voltage, may exceed the maximum withstand voltage of the switching module 12, causing damage. At this time, the first transient voltage suppressor diode TVS1 and the second transient voltage suppressor diode TVS2 conduct because the voltage across them exceeds their breakdown voltage, clamping the overvoltage pulse within a safe threshold. This ensures that the voltage difference between the first and second terminals of the switching module 12 does not exceed its maximum withstand voltage, preventing damage to the switching module 12 due to the voltage exceeding its maximum withstand voltage.

[0070] The first end of the current detection module 11 serves as the input end of the overcurrent protection circuit 1, and the second end of the switch module 12 serves as the output end of the overcurrent protection circuit 1.

[0071] Because the output of overcurrent protection circuit 1 is typically connected to an inductive load, and the wiring harness at the back end of the intelligent power distribution device is also an inductive load, the thinner and longer the wire, the greater the inductance. When the inductive load is disconnected, because the inductor current cannot change abruptly, without a freewheeling circuit, the output voltage will be pulled down to a very low negative voltage. The larger the inductance, the greater the negative voltage formed. The negative voltage formed at the output port is directly proportional to the inductance and the rate of decrease in current.

[0072] Figure 10 It shows the voltage waveform and output current waveform of the overcurrent protection circuit output terminal to ground when the switching module is turned off. Figure 11This refers to the voltage difference waveform between the first and second terminals of the switching module and the output current waveform when the switching module is turned off. (Reference) Figure 10 and Figure 11 The green curve represents the current waveform, and the red curve represents the voltage waveform.

[0073] Assuming that when the output current of power supply 10 is greater than 200A, control module 13 turns off switch module 12. The inductive load will pull the voltage at the output of the overcurrent protection circuit to a very low negative voltage. If there is no first suppression element 14, this negative voltage can reach -50V at most. The maximum withstand voltage of switch module 12 in the 12V circuit system is 40V. The voltage between the first and second terminals of switch module 12 is 14V + |-50V| = 64V, which far exceeds the maximum voltage value of switch module 12 of 40V. Under this situation, there is a high probability of damaging switch module 12.

[0074] To address the damage to the switching module 12 caused by the negative voltage generated at the output of the overcurrent protection circuit due to a sudden drop in current from 200A to 0A on the inductor, this embodiment adds a first transient suppression diode (TVS1) and a second transient suppression diode (TVS2) to ground at the output of the switching module 12. When the switching module 12 is turned off, the reverse breakdown characteristic of the transient suppression diodes effectively limits the negative voltage at the output of the overcurrent protection circuit to below |-26V|, thereby keeping the voltage at the first and second terminals of the switching module 12 below 40V and preventing damage to the switching module 12 due to overvoltage.

[0075] Figure 12 The waveforms of the overcurrent protection circuit output to ground and the current waveform after adding the first transient suppression diode and the second transient suppression diode are shown. Figure 13 The waveforms of the voltage difference and current at the first and second terminals of the switching module are obtained after adding the first transient suppression diode and the second transient suppression diode.

[0076] refer to Figures 10 to 13 When the output current of power supply 10 is greater than 200A, the voltage at the output terminal of the overcurrent protection circuit drops from -26V to -12V, and the voltage difference between the first and second terminals of switch module 12 drops from 64V to 26V.

[0077] Based on the same inventive concept, this utility model also provides an intelligent power distribution device, including the overcurrent protection circuit provided in any embodiment of this utility model, which has the same functional modules and beneficial effects as the overcurrent protection circuit. The similarities can be referred to the explanation of the overcurrent protection circuit, and will not be repeated here.

[0078] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An overcurrent protection circuit, characterized in that, include: The system comprises a current detection module, a switching module, a control module, and at least one first suppression element; The first end of the current detection module is connected to the output end of the power supply, the second end of the current detection module is connected to the first end of the switch module, and the output end of the current detection module is connected to the input end of the control module. The current detection module is used to collect the output current of the power supply. The second end of the switch module is connected to the load, the control end of the switch module is connected to the output end of the control module, and the control module is configured to control the switch module to turn off when the output current is greater than a set threshold. The first suppression element is connected in parallel to the first and second terminals of the switching module, and is used to suppress the overvoltage pulse generated at the second terminal of the switching module when the switching module is turned off.

2. The overcurrent protection circuit according to claim 1, characterized in that, The first suppression element includes a first transient suppression diode, which is connected in parallel to the first and second terminals of the switching module.

3. The overcurrent protection circuit according to claim 1, characterized in that, It also includes at least one second suppression element; The first end of the second suppression element is connected to the second end of the switch module, and the second end of the second suppression element is connected to a reference ground. The second suppression element is used to suppress the overvoltage pulse generated at the second end of the switch module when the switch module is turned off.

4. The overcurrent protection circuit according to claim 3, characterized in that, The second suppression element includes a second transient suppression diode, with the first end of the second transient suppression diode serving as the first end of the second suppression element, and the second end of the second transient suppression diode serving as the second end of the second suppression element.

5. The overcurrent protection circuit according to claim 1, characterized in that, The switching module includes a first switching unit and a second switching unit, both of which have a first terminal, a second terminal, and a control terminal; the control module includes a microcontroller chip, which has a first output pin and a second output pin, and the first and second output pins of the microcontroller chip serve as the output terminals of the control module. The control terminal of the first switch unit is connected to the first output pin, the first terminal of the first switch unit serves as the first terminal of the switch module, and the second terminal of the first switch unit is connected to the second terminal of the second switch unit. The control terminal of the second switching unit is connected to the second output pin, and the first terminal of the second switching unit serves as the second terminal of the switching module.

6. The overcurrent protection circuit according to claim 1, characterized in that, The switching module includes a first MOSFET and a second MOSFET; both the first MOSFET and the second MOSFET include a gate, a source, and a drain; the control module includes a microcontroller chip, which has a first output pin and a second output pin, and the first and second output pins of the microcontroller chip serve as the output terminals of the control module. The gate of the first MOSFET is connected to the first output pin, the source of the first MOSFET serves as the first terminal of the switching module, and the drain of the first MOSFET is connected to the drain of the second MOSFET. The gate of the second MOSFET is connected to the second output pin, and the source of the second MOSFET serves as the second terminal of the switching module.

7. The overcurrent protection circuit according to claim 1, characterized in that, It also includes a drive module, the input of which is connected to the output of the control module, and the output of which is connected to the control of the switch module. The drive module is used to amplify the signal output by the control module.

8. The overcurrent protection circuit according to claim 1, characterized in that, The current detection module includes a detection resistor and an operational amplifier; the operational amplifier has a first input terminal, a second input terminal, and an output terminal. The first end of the detection resistor serves as the first end of the current detection module, and the second end of the detection resistor serves as the second end of the current detection module. The first input terminal of the operational amplifier is connected to the first terminal of the detection resistor, the second input terminal of the operational amplifier is connected to the second terminal of the detection resistor, and the output terminal of the operational amplifier serves as the output terminal of the current detection module.

9. The overcurrent protection circuit according to claim 1, characterized in that, The load is an inductive load.

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

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