Battery charging current limiting circuit

Abstract

The utility model provides a battery charging current limiting circuit. A current limiting working sub-circuit comprises a second MOS tube; the current limiting control sub-circuit comprises a PMW controller, a charging state switching module, a gate driver and a sampling resistor. A drain electrode of the first MOS tube is connected with an external power supply through a first current-limiting resistor, a grid electrode of the first MOS tube is connected with a pre-charging control signal through a first driving resistor, and a source electrode of the first MOS tube is connected with a sampling resistor; the source electrode of the second MOS tube is connected with the source electrode of the first MOS tube through the sampling resistor, and the drain electrode of the second MOS tube is connected to the negative electrode of the battery; the output end of the PMW controller is connected with the grid electrode of the second MOS tube through a grid electrode driver, and a feedback input pin of the PMW controller is connected with the charging state switching module; and the charging state switching module accesses a current-limiting switching signal and is connected with the sampling resistor. Transient large current impact can be effectively suppressed, accurate current amplitude limiting control is achieved, charging efficiency and safety are improved, and the service life of a battery is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery charging current limiting circuit. BACKGROUND

[0002] With the popularity of electric devices, the demand for efficient and safe battery charging management technology is increasing. In particular in applications such as lithium-ion batteries, the charging process needs to be strictly controlled to avoid battery performance degradation or safety accidents caused by overcurrent, overvoltage, etc. Therefore, designing an efficient charging circuit with constant current and constant voltage charging functions and supporting trickle float has become a research hotspot.

[0003] In the prior art, when the battery starts charging, the external power supply connection of the common battery charging management circuit can easily cause a transient large current impact, which may damage the power devices in the circuit. The current limit in the main loop is often realized by a simple current limiting resistor, which is difficult to adjust the charging current flexibly according to the battery state, resulting in low charging efficiency or being harmful to the battery life. CONTENT OF THE INVENTION

[0004] Therefore, the purpose of the present application is to provide a battery charging current limiting circuit that can effectively suppress transient large current impact and achieve precise current limiting control, thereby improving charging efficiency and safety and prolonging battery life.

[0005] In a first aspect, the embodiments of the present application provide a battery charging current limiting circuit, comprising: a pre-charging electronic circuit, a current limiting working sub-circuit and a current limiting control sub-circuit.

[0006] The pre-charging electronic circuit comprises a first current limiting resistor, a first drive resistor and a first MOS tube; the current limiting working sub-circuit comprises a second MOS tube; the current limiting control sub-circuit comprises a PMW controller, a charging state switching module, a gate driver and a sampling resistor.

[0007] The drain of the first MOS tube is connected to an external power supply through the first current limiting resistor, the gate of the first MOS tube is connected to a pre-charging control signal through the first drive resistor, and the source of the first MOS tube is connected to the sampling resistor.

[0008] The source of the second MOS tube is connected to the source of the first MOS tube through the sampling resistor, and the drain of the second MOS tube is connected to the negative electrode of the battery.

[0009] The output of the PMW controller is connected to the gate of the second MOS tube through the gate driver, and the feedback input pin of the PMW controller is connected to the charging state switching module; the charging state switching module is connected to a current limiting switching signal and the sampling resistor.

[0010] With reference to the first aspect, in a first possible implementation of the first aspect, the charging state switching module comprises an operational amplifier, a third MOS transistor, a first voltage dividing resistor and a second voltage dividing resistor;

[0011] An input terminal of the operational amplifier is connected to both ends of the sampling resistor, and an output terminal of the operational amplifier is connected to the feedback input pin of the PMW controller through the first voltage dividing resistor;

[0012] A gate of the third MOS transistor is connected to the current-limiting switching signal, a drain of the third MOS transistor is connected to the feedback input pin of the PMW controller through the second voltage dividing resistor, and a source of the third MOS transistor is grounded.

[0013] With reference to the first aspect, in a second possible implementation of the first aspect, the current-limiting control sub-circuit further comprises a second driving resistor;

[0014] The second driving resistor is connected between the gate of the second MOS transistor and the gate driver.

[0015] With reference to the first aspect, in a third possible implementation of the first aspect, the charging state switching module further comprises a third driving resistor;

[0016] The third driving resistor is connected to the gate of the third MOS transistor.

[0017] With reference to the first aspect, in a fourth possible implementation of the first aspect, the pre-charging sub-circuit further comprises an RC filter module;

[0018] The RC filter module is connected between the first current-limiting resistor and the source of the first MOS transistor.

[0019] With reference to the first aspect, in a fifth possible implementation of the first aspect, the RC filter module comprises a second current-limiting resistor and a first filter capacitor;

[0020] The filter capacitor is connected in parallel to both ends of the first current-limiting resistor;

[0021] The second current-limiting resistor is connected in parallel between the source and the drain of the first MOS transistor.

[0022] With reference to the first aspect, in a sixth possible implementation of the first aspect, the current-limiting working sub-circuit further comprises a resonance filter module, and the resonance filter module comprises a resonance inductor and a second filter capacitor;

[0023] The resonant inductor is connected between the drain of the second MOS tube and the negative electrode of the battery.

[0024] The second filter capacitor is connected in parallel with the battery.

[0025] With reference to the first aspect, a seventh possible implementation of the first aspect is provided in embodiments of the present application, and the current-limiting working sub-circuit further comprises a protection diode.

[0026] The protection diode is connected in parallel with the second filter capacitor.

[0027] With reference to the first aspect, an eighth possible implementation of the first aspect is provided in embodiments of the present application, and the external power supply is connected to the positive electrode of the battery.

[0028] The negative electrode of the battery is grounded.

[0029] With reference to the first aspect, a ninth possible implementation of the first aspect is provided in embodiments of the present application, and a connection node between the source of the first MOS tube and the sampling resistor is grounded.

[0030] The battery charging current-limiting circuit provided in embodiments of the present application comprises a pre-charging electronic circuit, a current-limiting working sub-circuit and a current-limiting control sub-circuit. The pre-charging electronic circuit comprises a first current-limiting resistor, a first driving resistor and a first MOS tube. The current-limiting working sub-circuit comprises a second MOS tube. The current-limiting control sub-circuit comprises a PMW controller, a charging state switching module, a gate driver and a sampling resistor. The drain of the first MOS tube is connected to an external power supply through the first current-limiting resistor. The gate of the first MOS tube is connected to a pre-charging control signal through the first driving resistor. The source of the first MOS tube is connected to the sampling resistor. The source of the second MOS tube is connected to the source of the first MOS tube through the sampling resistor. The drain of the second MOS tube is connected to the negative electrode of the battery. The output of the PMW controller is connected to the gate of the second MOS tube through the gate driver. The feedback input pin of the PMW controller is connected to the charging state switching module. The charging state switching module is connected to a current-limiting switching signal and the sampling resistor. The battery charging current-limiting circuit can effectively suppress transient large current impact and realize precise current limiting control, thereby improving charging efficiency and safety and prolonging the service life of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. Other related drawings can also be obtained by those skilled in the art without creative labor.

[0032] Figure 1 A structure schematic view of a battery charging current limiting circuit provided by the utility model embodiment;

[0033] Figure 2 A structure schematic view of a battery charging current limiting circuit provided by the utility model embodiment;

[0034] Figure 3 A structure schematic view of a battery charging current limiting circuit provided by the utility model embodiment;

[0035] Figure 4 A structure schematic view of a battery charging current limiting circuit provided by the utility model embodiment.

[0036] Icon: 10-pre-charging electronic circuit; 20-current limiting working sub-circuit; 30-current limiting control sub-circuit; 11-first current limiting resistor; 12-first driving resistor; 13-first MOS tube; 21-second MOS tube; 31-PMW controller; 32-charging state switching module; 33-gate driver; 34-sampling resistor; 321-operational amplifier; 322-third MOS tube; 323-first voltage dividing resistor; 324-second voltage dividing resistor; 35-second driving resistor; 325-third driving resistor; 14-RC filtering module; 141-second current limiting resistor; 142-first filtering capacitor; 22-resonant filtering module; 23-protective diode; 221-resonant inductor; 222-second filtering capacitor. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the utility model embodiments clearer, the technical scheme in the utility model embodiments will be described clearly and completely below in combination with the drawings in the utility model embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the utility model embodiments described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model.

[0039] It should be noted that: similar labels and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0040] In the description of the utility model, it is understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the utility model product is used, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the utility model and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0041] In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0042] In the description of the utility model, it is also necessary to point out that, unless otherwise explicitly specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0043] It is considered that in the prior art, when the battery charging management circuit starts charging, the external power supply is easy to cause transient large current impact, which may damage the power device in the circuit, and the current limit in the main circuit is often realized by a simple current limiting resistor, which is difficult to flexibly adjust the charging current according to the battery state, resulting in low charging efficiency or being harmful to the battery life.

[0044] The embodiment of the application provides a battery charging current limiting circuit, which comprises a pre-charging electronic circuit, a current limiting working sub-circuit and a current limiting control sub-circuit; the pre-charging electronic circuit comprises a first current limiting resistor, a first driving resistor and a first MOS tube; the current limiting working sub-circuit comprises a second MOS tube; the current limiting control sub-circuit comprises a PMW controller, a charging state switching module, a gate driver and a sampling resistor; the drain of the first MOS tube is connected with an external power supply through the first current limiting resistor, the gate of the first MOS tube is connected with a pre-charging control signal through the first driving resistor, and the source of the first MOS tube is connected with the sampling resistor; the source of the second MOS tube is connected with the source of the first MOS tube through the sampling resistor, and the drain of the second MOS tube is connected with a negative electrode of a battery; the output end of the PMW controller is connected with the gate of the second MOS tube through the gate driver, and the feedback input pin of the PMW controller is connected with the charging state switching module; the charging state switching module is connected with the sampling resistor and inputs a current limiting switching signal. The transient large current impact can be effectively inhibited, the precise current limiting control is realized, the charging efficiency and safety are improved, and the service life of the battery is prolonged.

[0045] Please refer to Figure 1 , Figure 1 The embodiment provides a structure schematic diagram of a battery charging current limiting circuit.

[0046] As shown in Figure 1 , the battery charging current limiting circuit comprises a pre-charging electronic circuit 10, a current limiting working sub-circuit 20 and a current limiting control sub-circuit 30.

[0047] Specifically, the pre-charging electronic circuit 10 comprises a first current limiting resistor 11, a first driving resistor 12 and a first MOS tube 13; the current limiting working sub-circuit 20 comprises a second MOS tube 21; and the current limiting control sub-circuit 30 comprises a PMW controller 31, a charging state switching module 32, a gate driver 33 and a sampling resistor 34.

[0048] Here, the drain of the first MOS tube 13 is connected with an external power supply through the first current limiting resistor 11, the gate of the first MOS tube 13 is connected with a pre-charging control signal through the first driving resistor 12, and the source of the first MOS tube 13 is connected with the sampling resistor 34; the source of the second MOS tube 21 is connected with the source of the first MOS tube 13 through the sampling resistor 34, and the drain of the second MOS tube 21 is connected with a negative electrode of a battery; the output end of the PMW controller 31 is connected with the gate of the second MOS tube 21 through the gate driver 33, and the feedback input pin of the PMW controller 31 is connected with the charging state switching module 32; the charging state switching module 32 is connected with the sampling resistor 34 and inputs a current limiting switching signal.

[0049] The external power source is connected to the positive pole of the battery, the negative pole of the battery is grounded, and the connection node between the source of the first MOS tube 13 and the sampling resistor 34 is grounded.

[0050] In the specific implementation, the pre-charging electronic circuit 10 is used to protect the main circuit from the impact of a large instantaneous current on the circuit components when the external power source is just turned on. The main function is to slowly charge the circuit through the first current-limiting resistor 11 before the second MOS tube 21 is turned on. After the external power source is turned on, the pre-charging control signal drives the first MOS tube 13 to conduct through the first driving resistor 12. After the first MOS tube 13 is turned on, the main circuit is slowly pre-charged through the first current-limiting resistor 11 to prevent a large current impact.

[0051] Further, the second MOS tube 21 in the current-limiting working sub-circuit 20 serves as a current-limiting MOS tube of the main circuit, controls the current size of the main circuit, and realizes the limitation of the current of the main circuit by controlling the on-off of the second MOS tube 21, thereby controlling the current size of the main circuit. The second MOS tube 21 on the main circuit is controlled by the PMW controller 31, and the on-off is adjusted by the duty cycle. The current-limiting value is determined by the feedback signal input by the feedback input pin of the PMW controller 31.

[0052] Further, in the current-limiting control sub-circuit 30, the sampling resistor 34 is used to detect the current size in the main circuit. The voltage signal between the two ends of the sampling resistor 34 is sent to the charging state switching module 32 through the input pin. The output of the charging state switching module 32 is connected to the feedback input pin ISENSE of the PMW controller 31. The output end of the PMW controller 31 drives the gate of the second MOS tube 21 through the gate driver 33.

[0053] The PWM controller 31 is used to accurately control the switching state of the second MOS tube 21 to realize current limiting and constant voltage charging. It monitors the current through the sampling resistor 34 and adjusts the duty cycle of the output PWM signal according to the feedback signal. When the current in the main circuit passes through the sampling resistor 34, a voltage difference is generated between the two ends. After amplification by the charging state switching module 32, the voltage difference is provided to the PWM controller 31 as a feedback signal. When the feedback signal is greater than the reference voltage (such as 1V), the PWM controller 31 controls the second MOS tube 21 to close, and the battery stops charging. When the feedback signal is less than the reference voltage (such as 1V), the PWM controller 31 controls the second MOS tube 21 to open, allowing the charging current to pass through.

[0054] Please refer to Figure 2 , Figure 2 A structure diagram of a battery charging current-limiting circuit provided by the embodiment.

[0055] As Figure 2As shown in the embodiment, the battery charging current limiting circuit comprises a pre-charging electronic circuit 10, a current limiting working sub-circuit 20 and a current limiting control sub-circuit 30.

[0056] Specifically, the pre-charging electronic circuit 10 comprises a first current limiting resistor 11, a first driving resistor 12 and a first MOS tube 13; the current limiting working sub-circuit 20 comprises a second MOS tube 21; the current limiting control sub-circuit 30 comprises a PMW controller 31, a charging state switching module 32, a gate driver 33 and a sampling resistor 34. The charging state switching module 32 comprises an operational amplifier 321, a third MOS tube 322, a first voltage dividing resistor 323 and a second voltage dividing resistor 324.

[0057] Here, the input end of the operational amplifier 321 is connected to the two ends of the sampling resistor 34, and the output end of the operational amplifier 321 is connected to the feedback input pin ISENSE of the PMW controller 31 through the first voltage dividing resistor 323; the gate of the third MOS tube 322 is connected to a current limiting switching signal, the drain of the third MOS tube 322 is connected to the feedback input pin ISENSE of the PMW controller 31 through the second voltage dividing resistor 324, and the source of the third MOS tube 322 is grounded.

[0058] In a specific implementation, the PMW controller 31 collects the main loop current signal through the sampling resistor 34 and amplifies it through the operational amplifier 321. When the current in the main loop passes through the sampling resistor 34, a small voltage difference is generated at the two ends. The micro voltage difference is amplified by the operational amplifier 321 to the feedback input pin ISENSE of the PMW controller 31.

[0059] Further, the current limiting switching signal is connected to the gate of the third MOS tube 322. When the current limiting switching signal is at a high level, the third MOS tube 322 is turned on, and the first voltage dividing resistor 323 and the second voltage dividing resistor 324 divide the voltage. The input voltage threshold of the operational amplifier 321 is increased after voltage division, thereby increasing the current trigger threshold at the two ends of the sampling resistor 34. Therefore, a larger current is required to trigger the shutdown of the PMW controller 31, thereby realizing larger constant current charging. When the current limiting switching signal is at a low level, the third MOS tube 322 is turned off, and the first voltage dividing resistor 323 alone functions as a current limiting resistor. At this time, the current trigger threshold at the two ends of the sampling resistor 34 is low, and the PMW controller 31 is more likely to be turned off. The charging current is limited to a smaller value, thereby realizing trickle charging.

[0060] Please refer to Figure 3 , Figure 3 for a structure schematic diagram of the battery charging current limiting circuit provided by the embodiment.

[0061] As Figure 3As shown in the figure, the battery charging current limiting circuit provided in this embodiment includes: a pre-charging sub-circuit 10, a current limiting working sub-circuit 20, and a current limiting control sub-circuit 30.

[0062] Specifically, the pre-charge sub-circuit 10 includes a first current-limiting resistor 11, a first driving resistor 12, and a first MOSFET 13; the current-limiting sub-circuit 20 includes a second MOSFET 21; and the current-limiting control sub-circuit 30 includes a PWM controller 31, a charging state switching module 32, a gate driver 33, and a sampling resistor 34. The charging state switching module 32 includes an operational amplifier 321, a third MOSFET 322, a first voltage divider resistor 323, and a second voltage divider resistor 324. The current-limiting control sub-circuit 30 also includes a second driving resistor 35; and the charging state switching module 32 also includes a third driving resistor 325.

[0063] Here, the second driving resistor 35 is connected between the gate of the second MOSFET 21 and the gate driver 33. The third driving resistor 325 is connected to the gate of the third MOSFET 322.

[0064] In a specific implementation, the output of the PWM controller 31 drives the gate of the second MOSFET 21 through the second driving resistor 35; the current limiting switching signal drives the gate of the third MOSFET 322 through the third driving resistor 325.

[0065] Please see Figure 4 , Figure 4 This is the fourth schematic diagram of a battery charging current limiting circuit provided in this embodiment.

[0066] like Figure 4 As shown in the figure, the battery charging current limiting circuit provided in this embodiment includes: a pre-charging sub-circuit 10, a current limiting working sub-circuit 20, and a current limiting control sub-circuit 30.

[0067] Specifically, the pre-charge sub-circuit 10 includes a first current-limiting resistor 11, a first driving resistor 12, and a first MOSFET 13; the current-limiting sub-circuit 20 includes a second MOSFET 21; the current-limiting control sub-circuit 30 includes a PWM controller 31, a charging state switching module 32, a gate driver 33, and a sampling resistor 34. The charging state switching module 32 includes an operational amplifier 321, a third MOSFET 322, a first voltage divider resistor 323, and a second voltage divider resistor 324. The current-limiting control sub-circuit 30 also includes a second driving resistor 35; the charging state switching module 32 also includes a third driving resistor 325. The pre-charge sub-circuit 10 also includes an RC filter module 14, which includes a second current-limiting resistor 141 and a first filter capacitor 142; the current-limiting sub-circuit 20 also includes a resonant filter module 22 and a protection diode 23, which includes a resonant inductor 221 and a second filter capacitor 222.

[0068] Here, the RC filter module 14 is connected between the first current-limiting resistor 11 and the source of the first MOS tube 13. The first filter capacitor 142 is connected in parallel to the two ends of the first current-limiting resistor 11; the second current-limiting resistor 141 is connected in parallel between the source and the drain of the first MOS tube 13. The resonant inductor 221 is connected between the drain of the second MOS tube 21 and the negative pole of the battery; the second filter capacitor 222 is connected in parallel to the battery. The protection diode 23 is connected in parallel to the second filter capacitor 222.

[0069] In a specific implementation, after the external power supply is turned on, the external power supply charges the first filter capacitor 142 through the first current-limiting resistor 11 to form a loop, and accesses the circuit through the first filter capacitor 142 and the second current-limiting resistor 141, which is used to filter the transient high voltage input by the power supply. The RC filter module 14 absorbs the transient high voltage input by the external power supply, thereby protecting the circuit.

[0070] Further, the resonant inductor 221 and the second filter capacitor 222 form a resonant filter, which is used to smooth the voltage and current in the main loop. The protection diode 23 is used to discharge the reverse voltage generated when the MOS tube is turned off, thereby protecting the safety of the circuit.

[0071] The battery charging current-limiting circuit provided by the embodiment of the present application comprises a pre-charging electronic circuit, a current-limiting working sub-circuit, and a current-limiting control sub-circuit. The pre-charging electronic circuit comprises a first current-limiting resistor, a first driving resistor, and a first MOS tube. The current-limiting working sub-circuit comprises a second MOS tube. The current-limiting control sub-circuit comprises a PMW controller, a charging state switching module, a gate driver, and a sampling resistor. The drain of the first MOS tube is connected to an external power supply through the first current-limiting resistor. The gate of the first MOS tube is connected to a pre-charging control signal through the first driving resistor. The source of the first MOS tube is connected to the sampling resistor. The source of the second MOS tube is connected to the source of the first MOS tube through the sampling resistor. The drain of the second MOS tube is connected to the negative pole of a battery. The output of the PMW controller is connected to the gate of the second MOS tube through the gate driver. The feedback input pin of the PMW controller is connected to the charging state switching module. The charging state switching module is connected to a current-limiting switching signal and the sampling resistor. The transient large current impact can be effectively suppressed, the precise current limiting control is realized, the charging efficiency and safety are improved, and the service life of the battery is prolonged.

[0072] The above merely provides preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery charging current limiting circuit, characterized in that, include: Precharge sub-circuit, current limiting sub-circuit, and current limiting control sub-circuit; The pre-charge sub-circuit includes a first current-limiting resistor, a first driving resistor, and a first MOSFET; the current-limiting operating sub-circuit includes a second MOSFET; the current-limiting control sub-circuit includes a PWM controller, a charging state switching module, a gate driver, and a sampling resistor. The drain of the first MOS transistor is connected to an external power supply through the first current-limiting resistor, the gate of the first MOS transistor is connected to a pre-charge control signal through the first driving resistor, and the source of the first MOS transistor is connected to the sampling resistor. The source of the second MOS transistor is connected to the source of the first MOS transistor through the sampling resistor, and the drain of the second MOS transistor is connected to the negative terminal of the battery. The output of the PWM controller is connected to the gate of the second MOS transistor through the gate driver, and the feedback input pin of the PWM controller is connected to the charging state switching module; the charging state switching module receives a current limiting switching signal and is connected to the sampling resistor.

2. The battery charging current limiting circuit according to claim 1, characterized in that, The charging state switching module includes an operational amplifier, a third MOSFET, a first voltage divider resistor, and a second voltage divider resistor. The input terminal of the operational amplifier is connected to both ends of the sampling resistor, and the output terminal of the operational amplifier is connected to the feedback input pin of the PMW controller through the first voltage divider resistor; The gate of the third MOS transistor is connected to the current limiting switching signal, the drain of the third MOS transistor is connected to the feedback input pin of the PMW controller through the second voltage divider resistor, and the source of the third MOS transistor is grounded.

3. The battery charging current limiting circuit according to claim 1, characterized in that, The current limiting control sub-circuit also includes a second driving resistor; The second driving resistor is connected between the gate of the second MOS transistor and the gate driver.

4. The battery charging current limiting circuit according to claim 2, characterized in that, The charging state switching module also includes a third driving resistor; The third driving resistor is connected to the gate of the third MOS transistor.

5. The battery charging current limiting circuit according to claim 1, characterized in that, The precharge electronic circuit also includes an RC filter module; The RC filter module is connected between the first current-limiting resistor and the source of the first MOSFET.

6. The battery charging current limiting circuit according to claim 5, characterized in that, The RC filter module includes a second current-limiting resistor and a first filter capacitor; The first filter capacitor is connected in parallel across the first current-limiting resistor; The second current-limiting resistor is connected in parallel between the source and drain of the first MOS transistor.

7. The battery charging current limiting circuit according to claim 1, characterized in that, The current limiting sub-circuit also includes a resonant filtering module, which includes a resonant inductor and a second filtering capacitor. The resonant inductor is connected between the drain of the second MOS transistor and the negative terminal of the battery; The second filter capacitor is connected in parallel with the battery.

8. The battery charging current limiting circuit according to claim 7, characterized in that, The current-limiting sub-circuit also includes a protection diode; The protection diode is connected in parallel with the second filter capacitor.

9. The battery charging current limiting circuit according to claim 1, characterized in that: The external power source is connected to the positive terminal of the battery. The negative terminal of the battery is grounded.

10. The battery charging current limiting circuit according to claim 1, characterized in that: The connection node between the source of the first MOS transistor and the sampling resistor is grounded.

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