Overcurrent protection circuit

Abstract

The utility model discloses an overcurrent protection circuit, and the circuit comprises a switch unit which is disposed in a loop of a battery pack and a load, and a first end of the switch unit is connected with the positive electrode of the battery pack; the detection resistor is arranged between the second end of the switch unit and the load; the protective resistor is arranged in a loop formed by the first end and the third end of the switch unit and the battery pack; the input end of the protection unit is used for detecting the voltage of the detection resistor, and the output end of the protection unit is connected to a loop formed by the battery pack and the protection unit; the output end of the protection unit is connected with the first end and the third end of the switch unit, and is used for short-circuiting the first end and the third end to disconnect the switch unit when the voltage at the two ends of the detection resistor is abnormal. Therefore, protection is started when the current in the loop is abnormal, so that the load loop is disconnected, and circuit simplification and low cost are realized on the premise of ensuring the function and reliability of the circuit.

Description

Technical Field

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

[0002] The application of new energy batteries in daily life and industry is becoming increasingly widespread. With the widespread use of batteries across various industries, the changing environmental factors in different fields and the increasingly complex battery systems designed to meet demand have brought about many new challenges, with safety undoubtedly being the primary concern. Among these, overcurrent protection is one of the crucial measures to ensure battery safety.

[0003] To achieve overcurrent protection in battery systems, related technologies typically require the use of multiple transistors for feedback control. However, this results in a large number of discrete components in the circuit, making the circuit complex and costly. Utility Model Content

[0004] In view of this, the embodiments of this application provide at least one overcurrent protection circuit that activates protection when the current in the circuit is abnormal, thereby disconnecting the load circuit and simplifying the circuit and reducing its cost while ensuring circuit functionality and reliability.

[0005] The technical solution of this application embodiment is implemented as follows:

[0006] This application provides an overcurrent protection circuit, which includes: a switching unit disposed in the circuit of the battery pack and the load, with the first terminal of the switching unit connected to the positive terminal of the battery pack; a sensing resistor disposed between the second terminal of the switching unit and the load; a protection resistor disposed in the circuit formed by the first and third terminals of the switching unit and the battery pack; and a protection unit whose input terminal is used to detect the voltage of the sensing resistor, and whose output terminal is connected to the circuit formed by the battery pack and the protection unit. The output terminal of the protection unit is connected to the first and third terminals of the switching unit respectively, and is used to short-circuit the first and third terminals to disconnect the switching unit when the voltage across the sensing resistor is abnormal.

[0007] In the above embodiments, overcurrent protection of the battery circuit can be achieved using only a switching unit, a sensing resistor, a protection resistor, and a protection unit. In the event of an abnormal voltage across the sensing resistor, the protection unit short-circuits the first and third terminals of the switching unit to disconnect the battery from the load and protect the load. At the same time, different components can be selected for the switching unit and the protection unit as needed, which can reduce costs and simplify the circuit structure while still achieving overcurrent protection.

[0008] In some embodiments, the protection unit is an optocoupler, the input terminals of which include a first input terminal and a second input terminal, and the output terminals of which include a first output terminal and a second output terminal; the first input terminal and the second input terminal are respectively connected to the two ends of the detection resistor; the first output terminal is connected to the first terminal of the switching unit, and the second output terminal is respectively connected to the negative terminal of the battery pack and the third terminal of the switching unit.

[0009] In some embodiments, the protection resistor is connected to the negative terminal of the battery pack and the third terminal of the switching unit, respectively.

[0010] In the above embodiments, overcurrent protection of the battery is achieved through optocouplers. Optocouplers can avoid malfunctions and will only trigger the protection mechanism when it is truly needed, thereby improving the stability and reliability of the battery during use. At the same time, the fast response speed of optocouplers can effectively protect the battery from damage.

[0011] In some embodiments, the protection unit is an infrared pair, the input terminal of the protection unit includes the emitting anode and emitting cathode of the infrared pair emitting tube, and the output terminal of the protection unit includes the receiving anode and receiving cathode of the infrared pair receiving tube; the emitting anode and emitting cathode are respectively connected to the two ends of the detection resistor; the receiving anode is connected to the positive terminal of the battery pack, and the receiving cathode is connected to the third terminal of the switching unit.

[0012] In some embodiments, the protection resistor is connected to the positive terminal of the battery pack and the third terminal of the switching unit, respectively.

[0013] In the above embodiments, using infrared photodiodes for overcurrent protection in the battery circuit can reduce overall costs and simplify system design. At the same time, wireless information transmission through infrared photodiode transmitters and receivers helps to monitor battery status in real time, detect abnormalities such as overcurrent in a timely manner, and take measures to improve the safety and reliability of battery use.

[0014] In some embodiments, the overcurrent protection circuit further includes a voltage divider resistor; the protection unit is a precision programmable reference unit, the input terminal of the protection unit is the reference terminal of the precision programmable reference unit, and the output terminal of the protection unit includes the anode output terminal and the cathode output terminal of the precision programmable reference unit; the reference terminal is connected between the load and the sensing resistor; the anode output terminal is connected to the first terminal of the switching unit, and the cathode output terminal is connected to the third terminal of the switching unit; the voltage divider resistor is connected between the positive terminal of the battery pack and the protection resistor.

[0015] In some embodiments, one end of the protection resistor is connected to the voltage divider resistor, and the other end is connected to both the cathode output terminal and the third terminal of the switching unit.

[0016] In the above embodiments, a precise programmable reference can monitor the current in the load circuit in real time and quickly cut off the power supply when the current exceeds a set threshold, thereby preventing damage to the battery and load due to abnormal current. Secondly, the precise programmable reference can improve detection accuracy and ensure battery safety under different operating conditions. Furthermore, when faced with instantaneous overload current or current surges during startup, the precise programmable reference can reduce the probability of false triggering, improving the reliability of the battery circuit.

[0017] In the above embodiments, the overcurrent protection circuit further includes a current-limiting resistor; the current-limiting resistor is connected to the negative terminal of the battery pack and the load, respectively.

[0018] In some embodiments, the magnitude of the current in the circuit can be limited by the current-limiting resistor in the load circuit, which can effectively reduce the current flowing through the load and prevent the load from being damaged due to excessive current.

[0019] In some embodiments, the overcurrent protection circuit further includes a filtering unit; the filtering unit includes a filtering resistor, a filtering inductor and a filtering capacitor, the filtering resistor and the filtering inductor are connected in series between the first terminal of the switching unit and the positive terminal of the battery pack, one end of the filtering capacitor is located between the filtering resistor and the filtering inductor, and the other end of the filtering capacitor is connected to the negative terminal of the battery pack.

[0020] In the above embodiments, the battery pack is filtered by a filter resistor, a filter inductor, and a filter capacitor to absorb and eliminate high-frequency spike noise and interference signals in the circuit, thereby obtaining a more stable DC signal.

[0021] In some embodiments, the switching unit is one of a transistor, a signal relay, and a metal-oxide-semiconductor field-effect transistor.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of this application. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with this application and, together with the specification, serve to explain the technical solutions of this application.

[0024] Figure 1 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 1 ;

[0025] Figure 2 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 2 ;

[0026] Figure 3 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 3 ;

[0027] Figure 4 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 4 ;

[0028] Figure 5 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 5 ;

[0029] Figure 6 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 6 ;

[0030] Figure 7 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 7 ;

[0031] Figure 8 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 8 ;

[0032] Figure 9 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 9 ;

[0033] Figure 10 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 10 . Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application are further described in detail below with reference to the accompanying drawings and embodiments. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0036] The terms “first / second / third” are used merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that “first / second / third” may be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application.

[0038] Currently, new energy sources are being used more and more widely in daily life and industry. They are not only applied to energy storage battery systems in hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand for them is also constantly increasing.

[0039] In this embodiment, the battery requiring overcurrent protection can be a single battery cell, also known as a battery unit. A single battery cell is a basic unit capable of converting chemical energy into electrical energy, and can be used to manufacture battery modules or battery packs to supply power to electrical devices. A single battery cell can be a rechargeable battery, which is a battery cell that can be recharged after discharge to reactivate its active materials and continue to be used. A single battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., but this embodiment is not limited to these types.

[0040] In this embodiment, the battery cell requiring overcurrent protection can be any shape, such as a square cell or a round cell. The cell typically refers to a battery cell, one of the basic units constituting a battery. The cell is the core component of a battery, responsible for storing and releasing electrical energy. Cells can be lithium-ion cells (Li-ion Cell), lithium-polymer cells (Li-polymer Cell), nickel-metal hydride cells (NiMH Cell), etc. This embodiment does not limit the type of cell; it can be selected based on the actual application scenario. In this embodiment, the cell is the core component of the battery pack. A battery pack typically includes multiple cells, which are combined to provide the required energy capacity and voltage. The components of a battery pack include at least: individual battery cells, a battery management system (BMS), a casing, wiring harnesses, connectors, and interfaces. These components work together to combine the individual battery cells into a fully functional battery pack for various application scenarios. For example, battery packs can be used in electric vehicles, energy storage systems, portable electronic devices, solar energy systems, wind energy systems, emergency backup power supplies, power tools, or electric bicycles, etc. This application does not impose any limitations on these applications; specific applications can be selected based on actual usage scenarios.

[0041] In this embodiment, the battery requiring overcurrent protection can also be a single physical module comprising one or more individual battery cells to provide higher voltage and capacity. When there are multiple battery cells, they are connected in series, parallel, or mixed via a busbar assembly.

[0042] Overcurrent protection is a protection mechanism that activates a protective device in the battery circuit to disconnect the battery circuit and protect the battery when the current in the battery circuit exceeds a predetermined maximum value. When the current flowing through the protected component in the battery circuit exceeds a pre-set value, the protection device activates and disconnects the circuit. Without overcurrent protection, components are easily damaged if a short circuit or component malfunction causes excessive current. This is especially important in circuits that are highly sensitive to current changes.

[0043] Related technologies typically require the use of multiple transistors for feedback control; however, this results in a large number of discrete components in the circuit, making the circuit complex and costly.

[0044] To address the issue of overcurrent protection requiring multiple discrete components in related technologies, the applicant provides an overcurrent protection circuit comprising a switching unit, a sensing resistor, a protective resistor, and a protection unit. The switching unit is positioned in the circuit between the battery pack and the load, with its first terminal connected to the positive terminal of the battery pack. The sensing resistor is positioned between the second terminal of the switching unit and the load. The protective resistor is positioned in the circuit formed by the first and third terminals of the switching unit and the battery pack. The protection unit has an input terminal for detecting the voltage across the sensing resistor, and an output terminal connected to the circuit formed by the battery pack and the protection unit. The output terminal of the protection unit is connected to both the first and third terminals of the switching unit, and is used to short-circuit the first and third terminals to disconnect the switching unit in the event of an abnormal voltage across the sensing resistor.

[0045] First, the embodiments of this application can achieve overcurrent protection of the battery circuit using only a switching unit, a sensing resistor, a protection resistor, and a protection unit. In the event of an abnormal voltage across the sensing resistor, the protection unit short-circuits the first and third terminals of the switching unit to disconnect the battery from the load and protect the load. At the same time, different components can be selected for the switching unit and the protection unit as needed, which can reduce costs and simplify the circuit structure while still achieving overcurrent protection.

[0046] Figure 1 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 1 ,like Figure 1As shown, the overcurrent protection circuit includes a switching unit Q, a sensing resistor R1, a protection resistor R2, and a protection unit U. The switching unit Q is located in the circuit between the battery pack B and the load L, with its first terminal 1 connected to the positive terminal of the battery pack B. The sensing resistor R1 is located between the second terminal 2 of the switching unit Q and the load L. The protection resistor R2 is located in the circuit formed by the first terminal 1 and the third terminal 3 of the switching unit Q and the battery pack B. The protection unit U has an input terminal (Input) used to detect the voltage across the sensing resistor R1, and an output terminal (Output) connected to the circuit formed by the battery pack B and the protection unit U.

[0047] Here, the output terminal Output of the protection unit U is connected to the first terminal 1 and the third terminal 3 of the switching unit Q, respectively, and is used to short-circuit the first terminal 1 and the third terminal 3 to disconnect the switching unit Q when the voltage across the detection resistor R1 is abnormal.

[0048] Here, the switching unit Q can be one of a transistor, a signal relay, or a metal-oxide-semiconductor field-effect transistor (MOSFET). When the switching unit is a MOSFET, the first terminal of the switching unit Q is the gate of the MOSFET, and the second and third terminals are the source and drain, respectively.

[0049] In this embodiment, when the circuit is in normal operating condition, the gate of the switching unit Q is connected to the negative terminal of the battery pack B, making the gate-source voltage of the switching unit Q higher than the threshold voltage of the MOSFET. The switching unit Q is then turned on, and the battery pack B supplies power to the load L, forming a loop back to the negative terminal of the battery pack B through the sensing resistor R1. At this time, the current in the load circuit is normal, and the voltage across the sensing resistor R1 is relatively low. Therefore, the protection unit U is in an inactive state, and the circuit is in normal operating condition.

[0050] In some embodiments, the protection unit U may be an optocoupler, an optoMOS, or other optoelectronic devices.

[0051] When an abnormal overcurrent occurs in the circuit, the voltage across the detection resistor R1 becomes abnormal, causing the output terminal of the protection unit U to connect. The battery pack B forms a loop through the protection resistor R2. At this time, the first and third terminals of the switching unit Q are short-circuited, causing the switching unit Q to disconnect. That is, the loop between the battery pack B and the load L is disconnected, thus realizing the protection function of the overcurrent protection circuit.

[0052] Here, when the protection unit U is an optocoupler, if the voltage across the detection resistor R1 is abnormal, the receiving end (i.e., the light-emitting diode) of the optocoupler U operates. Upon receiving the signal, the output end of the optocoupler U responds quickly, turning on the transistor or MOSFET at the output end. This short-circuits the first and third terminals of the switching unit Q, causing the switching unit Q to disconnect, thus breaking the circuit between the battery pack B and the load, achieving the overcurrent protection function. After the circuit current returns to normal, the overcurrent protection circuit resumes normal operation.

[0053] In the embodiments of this application, when the gate and source of the MOSFET are shorted, the voltage difference (Vgs) between the gate and source becomes zero, thereby causing the MOSFET to be turned off or disconnected.

[0054] Thus, the embodiments of this application can achieve overcurrent protection of the battery circuit using only a switching unit, a sensing resistor, a protection resistor, and a protection unit. In the event of an abnormal voltage across the sensing resistor, the protection unit short-circuits the first and third terminals of the switching unit to disconnect the battery from the load and protect the load. At the same time, different components can be selected for the switching unit and the protection unit as needed, which can reduce costs and simplify the circuit structure while still achieving overcurrent protection.

[0055] Figure 2 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 2 ,like Figure 2 As shown, the protection unit U can be an optocoupler. The input terminals of the optocoupler include a first input terminal Input1 and a second input terminal Input2. The output terminals of the optocoupler include a first output terminal Output1 and a second output terminal Output2. The first input terminal Input1 and the second input terminal Input1 are respectively connected to the light-emitting diode in the optocoupler. The first output terminal Output1 and the second output terminal Output2 are respectively connected to the photosensitive element (such as a phototransistor or a photodiode) in the optocoupler.

[0056] Here, the first input terminal Input1 and the second input terminal Input2 are connected to the two ends of the detection resistor R1, respectively. The first output terminal Output1 is connected to the first terminal 1 of the switching unit Q, and the second output terminal Output2 is connected to the negative terminal of the battery pack B and the third terminal 3 of the switching unit Q, respectively. The protection resistor R2 is connected to the negative terminal of the battery pack B and the third terminal 3 of the switching unit Q, respectively. Figure 2 Q in the equation stands for PMOS.

[0057] Here, when an abnormal voltage is detected across resistor R1, the electrical signals at the first input terminal Input1 and the second input terminal Input2 drive the LED of the optocoupler to emit light. The light signal is transmitted through the isolation layer to the photosensitive element at the output terminal. Upon receiving the light signal, the photosensitive element generates a photocurrent, connecting the first output terminal Output1 and the second output terminal Output2. This short-circuits the first and third terminals of the switching unit Q, causing the switching unit Q to disconnect. This disconnects the circuit between battery pack B and the load, thus achieving the overcurrent protection function. After the circuit current returns to normal, the overcurrent protection circuit resumes normal operation.

[0058] In this embodiment, the switching unit Q can be a PMOS transistor or an NMOS transistor. Figure 3 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 3 ,like Figure 3 The diagram shows the circuit structure when the switching unit Q is an NMOS transistor.

[0059] In this embodiment, overcurrent protection of the battery is achieved through optocouplers. Optocouplers can avoid malfunctions and will only trigger the protection mechanism when it is truly needed, thereby improving the stability and reliability of the battery during use. At the same time, the fast response speed of optocouplers can effectively protect the battery from damage.

[0060] Figure 4 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 4 ,like Figure 4 As shown, the protection unit U can be an infrared diode pair, which consists of an infrared diode emitter and an infrared diode receiver. The infrared diode emitter can be an infrared light-emitting diode, capable of converting electrical energy into infrared light and emitting it. The infrared diode receiver can be a photodiode, whose core component can be a PN junction, operating under reverse voltage.

[0061] like Figure 4 As shown, the input terminal of the protection unit includes the anode a and cathode b of the infrared LED1 transmitter, and the output terminal includes the anode c and cathode d of the infrared LED2 receiver. The anode a and cathode b are connected to the two ends of the detection resistor R1, respectively. The anode c is connected to the positive terminal of the battery pack B, and the cathode d is connected to the third terminal 3 of the switching unit Q. Here, the protection resistor R2 is connected to both the positive terminal of the battery pack B and the third terminal 3 of the switching unit Q.

[0062] Here, the switching unit Q can be an NMOS transistor. The gate of the switching unit Q is connected to the positive terminal of the battery pack through the protection resistor R2, so that the switching unit Q is turned on to supply power to the load circuit. At this time, the current of the load circuit is normal, and the voltage of the sensing resistor R1 is small, so that the infrared light-emitting diode pair (i.e., LED1 / LED2) is in the non-working state, and the circuit is in the normal working state.

[0063] When an abnormal overcurrent occurs in the circuit, the voltage across the detection resistor R1 becomes abnormal, causing the infrared LED pair (LED1 / LED2) to activate. LED1 illuminates, and LED2 responds quickly upon receiving the signal. Battery pack B forms a circuit through the protection resistor R2 and LED2. LED2 short-circuits the gate and source of the switching unit Q, causing Q to disconnect, thus achieving overcurrent protection. Once the circuit current returns to normal, it resumes normal operation.

[0064] In the embodiments of this application, Figure 4 The switching unit Q in the diagram is a PMOS transistor. Figure 5 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 5 ,like Figure 5 The diagram shows the circuit structure when the switching unit Q is an NMOS transistor.

[0065] In this embodiment, using infrared photodiodes for overcurrent protection in the battery circuit can reduce overall cost and simplify system design. At the same time, wireless information transmission through infrared photodiode transmitters and receivers helps to monitor battery status in real time, detect abnormalities such as overcurrent in a timely manner, and take measures to improve the safety and reliability of battery use.

[0066] Figure 6 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 6 ,like Figure 6 As shown, the overcurrent protection circuit also includes a voltage divider resistor R3. The protection unit U can be a precision programmable reference unit. The input terminal of the protection unit U is the reference terminal x of the precision programmable reference unit, and the output terminals of the protection unit include the anode output terminal y and the cathode output terminal z of the precision programmable reference unit. The reference terminal x is connected between the load L and the sensing resistor R1. The anode output terminal y is connected to the first terminal 1 of the switching unit Q, and the cathode output terminal z is connected to the third terminal 3 of the switching unit Q. One end of the protection resistor R2 is connected to the positive terminal of the battery pack B, and the other end is connected to both the cathode output terminal z and the third terminal 3 of the switching unit Q.

[0067] In some embodiments, the voltage divider resistor R3 is connected between the positive terminal of battery pack B and the protection resistor R2 to prevent the battery pack from short-circuiting.

[0068] Here, the switching unit Q can be an NMOS transistor. The gate of the switching unit Q is connected to the positive terminal of the power supply through the protection resistor R2, which turns on the MOS transistor Q to supply power to the load circuit. At this time, the current of the load circuit is normal, and the voltage of the sensing resistor R1 is small, so that the precision programmable reference (such as TL431) is in a non-working state, and the circuit is in a normal working state.

[0069] When an abnormal overcurrent occurs in the circuit, the voltage across the sensing resistor R1 rises. When this voltage exceeds the built-in reference voltage Vref of the precision programmable reference (typically 2.5V), the anode output terminal y and cathode output terminal z of the precision programmable reference conduct. Battery pack B forms a circuit through the protection resistor R2 and the precision programmable reference, short-circuiting the gate and source of the switching unit Q, causing the switching unit Q to disconnect and achieving overcurrent protection. After the circuit current returns to normal, it resumes normal operation.

[0070] In some embodiments, the precision programmable reference can be composed of an operational amplifier and a transistor (or diode). When the voltage at the reference terminal x is greater than 2.5V, the operational amplifier outputs a low level "1", the base voltage of the transistor is high, and the collector junction and emitter junction of the transistor are turned on, which is equivalent to the anode output terminal y and the cathode output terminal z being turned on.

[0071] In the embodiments of this application, Figure 6 The switching unit Q in the diagram is a PMOS transistor. Figure 7 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 7 ,like Figure 7 The diagram shows the circuit structure when the switching unit Q is an NMOS transistor.

[0072] In this embodiment, a precise programmable reference can monitor the current in the load circuit in real time and quickly cut off the power supply when the current exceeds a set threshold, thereby preventing damage to the battery and load due to abnormal current. Secondly, the precise programmable reference can improve detection accuracy and ensure battery safety under different operating conditions. Furthermore, when faced with instantaneous overload current or current surges during startup, the precise programmable reference can reduce the probability of false triggering, improving the reliability of the battery circuit.

[0073] In some embodiments, based on Figure 1 , Figure 8 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 8 ,like Figure 8 As shown, the overcurrent protection circuit also includes a current-limiting resistor R4, which is connected to the negative terminal of battery pack B and the load L, respectively.

[0074] In this embodiment, the current in the load circuit can be limited by the current-limiting resistor, which can effectively reduce the current flowing through the load and prevent the load from being damaged due to excessive current.

[0075] based on Figure 8 , Figure 9 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 9 ,like Figure 9 As shown, the overcurrent protection circuit also includes a filtering unit, which includes a filtering resistor R5, a filtering inductor L1, and a filtering capacitor C. The filtering resistor R5 and the filtering inductor L1 are connected in series between the first terminal 1 of the switching unit Q and the positive terminal of the battery pack B. One end of the filtering capacitor C is located between the filtering resistor R5 and the filtering inductor L1, and the other end of the filtering capacitor C is connected to the negative terminal of the battery pack B.

[0076] In this embodiment, battery pack B is filtered by filter resistor R5, filter inductor L1 and filter capacitor C to absorb and eliminate high-frequency spike noise and interference signals in the circuit, thereby obtaining a more stable DC signal.

[0077] Figure 10 This is a schematic diagram of the overcurrent protection circuit provided in the embodiments of this application. Figure 10 Overcurrent circuit structure as follows Figure 10 As shown in the embodiment of this application, another overcurrent protection circuit is provided. In the initial normal working state, the battery pack B is filtered by the filter resistor R5, the filter inductor L1 and the filter capacitor C to absorb and eliminate high-frequency spike noise and interference signals in the circuit, so as to obtain a more stable DC signal, which then returns to the negative terminal of the battery pack B through the first voltage divider resistor R6 and the second voltage divider resistor R7.

[0078] In this embodiment, the MOSFET Q is turned on to supply power to the load circuit by voltage division through the first voltage divider resistor R6 and the second voltage divider resistor R7. At this time, the current of the load circuit is normal, and the voltage of the detection resistor R1 is small, so that the protection unit (i.e., optoMOS / optocoupler) U is in an inactive state, and the circuit is in a normal operating state.

[0079] When an abnormal overcurrent occurs in the circuit, the abnormal voltage across the detection resistor R1 activates the LED of the switching unit (e.g., opto-MOS / optocoupler) U. Upon receiving the signal, the opto-MOS / optocoupler U responds quickly, turning on its transistor or MOS. The battery pack B forms a circuit through the switching unit U and the first voltage divider resistor R6, pulling up the gate voltage of the MOS transistor Q. This reliably ensures that the gate of the MOS transistor Q is connected to the battery pack, causing the MOS transistor Q to disconnect and achieving overcurrent protection. Once the circuit current returns to normal, it resumes normal operation.

[0080] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0081] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0082] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An overcurrent protection circuit, characterized by comprising: The overcurrent protection circuit comprises: a switch unit arranged in a loop of a battery pack and a load, a first end of the switch unit being connected with a positive electrode of the battery pack; a detection resistor arranged between a second end of the switch unit and the load; a protection resistor arranged in a loop of the first end and a third end of the switch unit and the battery pack; a protection unit, an input end of the protection unit being used for detecting a voltage of the detection resistor, an output end of the protection unit being connected to a loop of the battery pack and the protection unit; the output end of the protection unit being connected with the first end and the third end of the switch unit respectively, and being used for short-circuiting the first end and the third end to disconnect the switch unit in a case that a voltage between the two ends of the detection resistor is abnormal.

2. The overcurrent protection circuit of claim 1, wherein, The protection unit is an optical coupler, an input end of the optical coupler comprising a first input end and a second input end, an output end of the optical coupler comprising a first output end and a second output end; the first input end and the second input end being connected with the two ends of the detection resistor respectively; the first output end being connected with the first end of the switch unit, and the second output end being connected with a negative electrode of the battery pack and the third end of the switch unit respectively.

3. The overcurrent protection circuit of claim 2, wherein, The protection resistor is connected with the negative electrode of the battery pack and the third end of the switch unit respectively.

4. The overcurrent protection circuit of claim 1, wherein, The protection unit is an infrared pair tube, an input end of the protection unit comprising an anode of an emission tube of an emission tube of the infrared pair tube and a cathode of the emission tube, an output end of the protection unit comprising an anode of a receiving tube of a receiving tube of the infrared pair tube and a cathode of the receiving tube; the anode of the emission tube and the cathode of the emission tube being connected with the two ends of the detection resistor respectively; the anode of the receiving tube being connected with the positive electrode of the battery pack, and the cathode of the receiving tube being connected with the third end of the switch unit.

5. The overcurrent protection circuit of claim 4, wherein, The protection resistor is connected with the positive electrode of the battery pack and the third end of the switch unit respectively.

6. The overcurrent protection circuit of claim 1, wherein, The overcurrent protection circuit further comprises a voltage dividing resistor; the protection unit is a precision programmable reference unit, an input end of the protection unit being a reference end of the precision programmable reference unit, an output end of the protection unit comprising an anode output end and a cathode output end of the precision programmable reference unit; the reference end being connected between the load and the detection resistor; the anode output end being connected with the first end of the switch unit, and the cathode output end being connected with the third end of the switch unit; the voltage dividing resistor being connected between the positive electrode of the battery pack and the protection resistor.

7. The overcurrent protection circuit of claim 6, wherein, One end of the protection resistor is connected with the voltage dividing resistor, and the other end is connected with the cathode output end and the third end of the switch unit respectively.

8. The overcurrent protection circuit according to any one of claims 1 to 7, characterized in that The overcurrent protection circuit further comprises a current limiting resistor; the current limiting resistor being connected with the negative electrode of the battery pack and the load respectively.

9. The overcurrent protection circuit according to any one of claims 1 to 7, characterized in that The overcurrent protection circuit further comprises a filter unit; the filter unit comprising a filter resistor, a filter inductor and a filter capacitor, the filter resistor and the filter inductor being arranged in series between the first end of the switch unit and the positive electrode of the battery pack, one end of the filter capacitor being arranged between the filter resistor and the filter inductor, and the other end of the filter capacitor being connected with the negative electrode of the battery pack.

10. The overcurrent protection circuit according to any one of claims 1 to 7, characterized in that, The switch unit is one of a triode, a signal relay and a metal oxide semiconductor field effect transistor. The switch unit is one of a triode, a signal relay and a metal oxide semiconductor field effect transistor.

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