Reverse charging prevention circuit and electric equipment

Abstract

The utility model provides an anti-reverse charging circuit and electric equipment, and belongs to the technical field of temperature control. The circuit comprises a controller and a switch assembly, the switch assembly comprises at least two field effect transistors which are connected in series; one end of the switch assembly is used for being connected with one end of the battery unit, and the other end of the switch assembly is used for being connected with a power supply; the other end of the battery unit is also used for connecting a power supply; the controller is connected with the two ends of the switch assembly and further connected with the control end of the field effect transistor. The controller is also connected with the battery unit; the controller controls the switch assembly to be switched off when detecting that the voltage at the two ends of the switch assembly is smaller than or equal to a preset threshold value. According to the invention, the possibility of damage to components of electric equipment caused by the fact that a user inserts the charger reversely by mistake can be reduced.

Description

Technical Field

[0001] This application relates to the field of battery control technology, and more specifically, to an anti-reverse charging circuit and an electrical device. Background Technology

[0002] With the development of technology, rechargeable batteries have been applied to various electrical devices, such as laptops and mobile phones. However, in actual use, there are two-ended chargers. When users use this type of charger to charge their devices, the charger may be plugged in backwards, causing the positive terminal of the power supply to be connected to the negative terminal of the device's charging circuit, and vice versa. This reverse plugging may damage the components in the device's circuitry. Utility Model Content

[0003] The purpose of this application is to provide a reverse charging circuit and electrical equipment to reduce the possibility of users accidentally plugging the charger in backwards, which could damage the components of the electrical equipment.

[0004] The embodiments of this application are implemented as follows:

[0005] A first aspect of this application provides a reverse charging protection circuit.

[0006] Controller, switching assembly; the switching assembly includes: at least two field-effect transistors connected in series;

[0007] One end of the switch assembly is used to connect to one end of the battery cell, and the other end of the switch assembly is used to connect to a power source;

[0008] The other end of the battery unit is also used to connect to a power source;

[0009] The controller is connected to both ends of the switching assembly and is also connected to the control terminal of the field-effect transistor; the controller is also connected to the battery cell.

[0010] When the controller detects that the voltage across the switching assembly is less than or equal to a preset threshold, it controls the switching assembly to disconnect.

[0011] Optionally, the controller includes at least two voltage detection pins, which are respectively connected to both ends of the switching assembly.

[0012] Optionally, the first preset threshold corresponding to the end of the switch assembly near the battery cell is greater than the second preset threshold corresponding to the end of the switch assembly used to connect to the power supply.

[0013] Optionally, the at least two field-effect transistors connected in series include a charging field-effect transistor and a discharging field-effect transistor;

[0014] One end of the charging field-effect transistor is connected to the battery cell, and the other end of the charging field-effect transistor is connected to one end of the discharging field-effect transistor.

[0015] The other end of the discharge field-effect transistor is used to connect to a power supply.

[0016] Optionally, the rated voltage of the charging field-effect transistor is less than a third preset threshold.

[0017] Optionally, the at least two field-effect transistors connected in series include three or more field-effect transistors;

[0018] One end of the first field-effect transistor in each of the field-effect transistors is connected to the battery cell, and the other end of the first field-effect transistor in each of the field-effect transistors is connected to one end of the second field-effect transistor in each of the field-effect transistors.

[0019] One end of the Nth field-effect transistor in each of the field-effect transistors is connected to the (N-1)th field-effect transistor in each of the field-effect transistors, and the other end of the Nth field-effect transistor in each of the field-effect transistors is connected to one end of the (N+1)th field-effect transistor in each of the field-effect transistors; where N is greater than or equal to 2 and N is not equal to M, and M is the number of each of the field-effect transistors;

[0020] One end of the last field-effect transistor in each of the field-effect transistors is connected to the field-effect transistor preceding the last field-effect transistor, and the other end of the first field-effect transistor in each of the field-effect transistors is used to connect to a power supply.

[0021] Optionally, a current detection module;

[0022] The first end of the current detection module is connected to the battery cell, and the second end of the current detection module is also used to connect to the power supply.

[0023] The controller is also connected to the current detection module for detecting the current in the charging circuit and / or discharging circuit.

[0024] Optionally, the controller is further configured to control the switching component to turn off when the detected current is greater than a preset threshold.

[0025] Optionally, the controller includes a fuel gauge chip.

[0026] A second aspect of this application provides an electrical device including any of the reverse charging protection circuits described above.

[0027] In this embodiment, the switching component includes at least two field-effect transistors connected in series. The controller is connected to both ends of the switching component and then detects the voltage across the two ends of the switching component. In this circuit architecture, if the charger is plugged in backwards, the positive terminal P+ of the charging circuit is connected to the negative terminal of the power supply, and the negative terminal P- of the charging circuit is connected to the positive terminal of the power supply. The voltage at one end Q of the switching component is 0, and the voltage at the other end P is also very low. Therefore, the controller only needs to detect that the voltage across the two ends of the switching component is less than or equal to a preset threshold to control the switching component to disconnect, thereby disconnecting the charging circuit. This can protect the field-effect transistors in the switching component and also protect other components in the electrical equipment.

[0028] Furthermore, since the voltage across the switching assembly is detected to prevent reverse insertion of the charger, all field-effect transistors in the switching module can be turned off. This method is not limited by the rated voltage of the field-effect transistors and does not require selecting field-effect transistors with corresponding rated voltages based on the number of battery cells in series. This reduces costs, makes production more convenient, and avoids the risk of breakdown caused by field-effect transistors near the positive terminal of the battery cell not being turned off. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 A schematic diagram of a reverse charging protection circuit provided for related technologies;

[0031] Figure 2 This is a schematic diagram of a reverse charging protection circuit provided in an embodiment of this application;

[0032] Figure 3 This is a schematic diagram of another anti-reverse charging circuit provided in an embodiment of this application;

[0033] Figure 4 This is a schematic diagram of another anti-reverse charging circuit provided in an embodiment of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0037] In the description of this application, it should be noted that the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] In related technologies, there exists a reverse charging circuit, as shown in the reference... Figure 1 It includes a battery cell 101, a controller 102, a CFET (charge field effect transistor) 104, a DFET (discharge field effect transistor) 105, and a reverse insertion detection field effect transistor 103.

[0040] The positive terminal of battery cell 101 is connected to the first terminal of CFET 104, and the second terminal of CFET 104 is connected to the first terminal of DFET 105. The control terminal of CFET 104 is connected to controller 102. The second terminal of DFET 105 is used to connect to the positive terminal of the power supply. The control terminal of DFET 105 is connected to controller 102. The first and second terminals of reverse insertion detection field-effect transistor 103 are respectively connected to the control terminal of DFET 105 and ground. The control terminal of reverse insertion detection field-effect transistor 103 is connected to the second terminal of DFET 105.

[0041] Among them, the reverse insertion detection field-effect transistor 103 can be a PMOS transistor.

[0042] When the charger is plugged in reverse, with the negative terminal connected to the positive terminal of the power supply and the positive terminal connected to the negative terminal, the control terminal of the reverse insertion detection field-effect transistor 103 goes low, turning on both its first and second terminals. The control terminal of the DFET 105 is also pulled low, turning off both its first and second terminals. However, in this configuration, the CFET 104 remains on. During reverse charging, the voltage of the battery cell 101 plus the charger voltage may exceed the rated voltage of the CFET 104, potentially causing it to break down. Therefore, in related technologies, to prevent the CFET 104 from breaking down during reverse insertion, a higher rated voltage is required, resulting in higher costs.

[0043] In this embodiment, which is equivalent to related technologies, the reverse insertion detection field-effect transistor 103 is removed. The controller 102 is directly connected to both ends of the switching assembly 30. When the voltage across the two ends of the switching assembly 30 is detected to be less than or equal to a preset threshold, the controller controls the switching assembly 30 to disconnect, thereby achieving reverse charging protection. Since all field-effect transistors in the switching assembly can be disconnected, it is not necessary to consider the impact of the voltage after reverse insertion on the field-effect transistors, and no additional reverse insertion detection field-effect transistor is required. This reduces costs and also prevents the field-effect transistors in the switching assembly from being damaged.

[0044] Reference Figure 2 The diagram illustrates a reverse charging protection circuit according to an embodiment of this application. The reverse charging protection circuit includes:

[0045] Controller 20, switching assembly 30; the switching assembly includes: at least two field-effect transistors 31 and 32 connected in series;

[0046] One end of the switch assembly 30 is used to connect to one end of the battery unit 10, and the other end of the switch assembly 30 is used to connect to a power source;

[0047] The other end of the battery unit 10 is also used to connect to a power source;

[0048] The controller 20 is connected to both ends of the switching assembly 30, and is also connected to the control terminals of the field-effect transistors 31 and 32; the controller 20 is also connected to the battery unit 10.

[0049] When the controller 20 detects that the voltage across the switch assembly 30 is less than or equal to a preset threshold, it controls the switch assembly 30 to open.

[0050] In this embodiment, during positive charging, the positive terminal of the battery cell 10 is connected to the first terminal of the switch assembly 30, and the second terminal of the switch assembly 30 can be used to connect to the positive terminal of the power supply. The negative terminal of the battery cell 10 can be used to connect to the negative terminal of the power supply.

[0051] The power source can be a socket connected to the power grid, or a charging device, such as a power bank.

[0052] The switching assembly 30 contains at least two field-effect transistors 31 and 32 connected in series. The number of field-effect transistors connected in series can be 2, 3, 4, etc., and this embodiment does not limit this. It can be understood that the first terminal formed by the series connection of the field-effect transistors is connected to the battery cell 10, and the second terminal formed by the series connection of the field-effect transistors is used to connect to the positive terminal of the power supply.

[0053] The control terminal of each field-effect transistor in the switching assembly 30 is connected to the controller 20.

[0054] The first terminal of the switching assembly 30 is connected to the controller 20 at point P, and the second terminal of the switching assembly 30 is connected to the controller 20 at point Q. Thus, the controller 20 can detect the voltage at points P and Q respectively.

[0055] When the charger is plugged in reverse (i.e., the negative terminal of the charger is connected to the positive terminal of the power supply, the second terminal of the switch assembly is connected to the positive terminal, the positive terminal of the charger is connected to the negative terminal of the power supply, and the negative terminal of the battery cell is connected to the positive terminal of the power supply), the voltage at Q is 0, while the voltage at P becomes the battery cell voltage plus the charger voltage.

[0056] The controller 20 will then detect the voltage at points P and Q. If the voltage at points P and Q meets the preset conditions, it will confirm that the charger is plugged in backwards. The controller 20 will then disconnect each field-effect transistor in the switching assembly 30, thereby disconnecting the charging circuit and realizing reverse insertion protection.

[0057] This preset condition includes, for example, the voltage at points P and Q being less than or equal to a certain preset threshold. The preset thresholds at points P and Q can be different.

[0058] In this embodiment, the switching component 30 includes at least two field-effect transistors connected in series. The controller is connected to both ends of the switching component 30 and then detects the voltage across the two ends of the switching component 30. In this circuit architecture, if the charger is plugged in backwards, the positive terminal P+ of the charging circuit is connected to the negative terminal of the power supply, and the negative terminal P- of the charging circuit is connected to the positive terminal of the power supply. The voltage at one end Q of the switching component 30 is 0, and the voltage at the other end P is also very low (specifically, the voltage of P is the charger voltage + the battery cell 10 voltage). Then, as long as the controller detects that the voltage across the two ends of the switching component 30 is less than or equal to a preset threshold, it controls the switching component 30 to open, thereby disconnecting the charging circuit. This protects the field-effect transistors in the switching component 30 and also protects other components in the electrical equipment.

[0059] Furthermore, since the voltage across the switch assembly 30 is detected to prevent the charger from being plugged in reverse, all field-effect transistors in the switch module can be turned off. This method is not limited by the rated voltage of the field-effect transistors and does not require selecting field-effect transistors with corresponding rated voltages based on the number of battery cells in series. This reduces costs, makes production more convenient, and avoids the risk of breakdown caused by field-effect transistors near the positive terminal of the battery cell not being turned off.

[0060] Optionally, in one embodiment of this application, the controller 20 includes at least two voltage detection pins 21 and 22, which are respectively connected to the two ends of the switching assembly 30.

[0061] In this embodiment, the controller 20 is provided with at least two voltage detection pins 21 and 22, wherein the two voltage detection pins can be respectively connected to the two ends of the switching assembly 30, for example... Figure 2 In the controller 20, one voltage detection pin is connected to the first end of the switching assembly 30 at point P, and another voltage detection pin of the controller 20 is connected to the second end of the switching assembly 30 at point Q.

[0062] In this way, the voltage across the switching component 30 can be detected based on the internal circuitry of the controller.

[0063] Understandably, when this anti-reverse charging circuit is connected to the charger to charge battery cell 10, Figure 2 The terminals P+ and P- shown can be used as the positive and negative terminals of the charging circuit, respectively, and when the charger is correctly inserted, terminals P+ and P- can be connected to the positive and negative terminals of the charger, respectively.

[0064] However, if the anti-reverse charging circuit is connected to the electrical load and the battery cell 10 discharges to the electrical load, Figure 2The terminals P+ and P- shown can be used as the positive and negative terminals of the discharge circuit, respectively, and when the electrical load is correctly inserted, terminals P+ and P- can be connected to the positive and negative terminals of the electrical load, respectively.

[0065] In this way, while using the anti-reverse charging circuit to prevent damage from reverse plugging of the charger, the normal charging and discharging function of the battery unit 10 will not be affected.

[0066] Optionally, in one embodiment of this application, the first preset threshold corresponding to the end of the switch assembly 30 near the battery cell 10 is greater than the second preset threshold corresponding to the end of the switch assembly 30 used to connect to the power supply.

[0067] For example, the first preset threshold value corresponding to the end of the switch assembly 30 near the battery cell 10 is 1;

[0068] The second preset threshold corresponding to the end of the switch assembly 30 used to connect to the power supply is 0.

[0069] like Figure 2 In this embodiment, when the charger is plugged in reverse for charging, the voltage at Q is 0, and the voltage at P is the battery cell voltage plus the charger voltage. Therefore, as long as the voltage at Q is detected to be 0 and the voltage at P is less than 1, reverse charging is confirmed, and the controller 20 can control the field-effect transistors 31 and 32 to disconnect. This condition determination is quick and the circuit implementation is simple.

[0070] Optionally, in one embodiment of this application, the control terminals of at least two series-connected field-effect transistors 31 and 32 are respectively connected to the control pins of the controller 20.

[0071] It is understood that each field-effect transistor of the switching assembly 30 is connected to a control pin of the controller 20, so that the controller can independently control each field-effect transistor.

[0072] In another embodiment of this application, each field-effect transistor of the switching component 30 can be connected to the same control pin of the controller 20. The field-effect transistors of the switching component 30 are of the same type. In this way, the controller 20 can control the field-effect transistors of the switching component 30 to be turned on or off by the same level signal.

[0073] Optionally, in one embodiment of this application, if the number of the at least two series-connected field-effect transistors is exactly 2, then the at least two series-connected field-effect transistors may include a charging field-effect transistor 31 and a discharging field-effect transistor 32.

[0074] One end of the charging field-effect transistor 31 is connected to the battery cell 10, and the other end of the charging field-effect transistor 31 is connected to one end of the discharging field-effect transistor 32.

[0075] The other end of the discharge field-effect transistor 32 is used to connect to a power supply.

[0076] The charging FET 31 and discharging FET 32 are important components of the battery management system (BMS), responsible for controlling the charging and discharging processes of the battery, respectively. The charging FET is a field-effect transistor connected between the external power source and the battery, used to control the opening and closing of the charging path. When the charging FET is turned on, the external power source can charge the battery; when the charging FET is turned off, the external power source cannot enter the battery, meaning the battery cannot be charged. However, the battery voltage can be output through the body diode of the FET.

[0077] A discharge FET is a field-effect transistor connected between a battery and a load, used to control the opening and closing of the discharge path. When the discharge FET is turned on, the battery can discharge; when the discharge FET is turned off, the battery's discharge path is completely cut off.

[0078] Optionally, in one embodiment of this application, the rated voltage of the charging field-effect transistor is less than a third preset threshold. If the charging field-effect transistor is a MOSFET, then the rated voltage may refer to the drain-source voltage Vds of the charging field-effect transistor, i.e., the absolute maximum voltage. When the charging field-effect transistor is working normally, the voltage difference between the drain and source of the charging field-effect transistor generally cannot exceed Vds.

[0079] In this embodiment, since each field-effect transistor 31 and 32 in the switching assembly 30 can be disconnected, the problem of the charging FET being broken down does not need to be considered in the reverse charging scenario. Therefore, the rated voltage of the charging FET does not need to take into account the additional voltage in the reverse charging scenario, and can be less than the third preset threshold and greater than or equal to the maximum voltage of the battery cell after it is fully charged.

[0080] Specifically, the third preset threshold may refer to the sum of the voltage of the charger and the voltage of the battery cell 10 in the reverse insertion charging scenario, or it may be any other possible voltage level. This application embodiment does not limit this.

[0081] Optionally, in one embodiment of this application, if the number of the at least two series-connected field-effect transistors is greater than or equal to 3, then the at least two series-connected field-effect transistors may include: three or more field-effect transistors;

[0082] One end of the first field-effect transistor in each field-effect transistor is connected to the battery cell, and the other end of the first field-effect transistor in each field-effect transistor is connected to one end of the second field-effect transistor in each field-effect transistor.

[0083] One end of the Nth field-effect transistor in each field-effect transistor is connected to the (N-1)th field-effect transistor in each field-effect transistor, and the other end of the Nth field-effect transistor in each field-effect transistor is connected to one end of the (N+1)th field-effect transistor in each field-effect transistor;

[0084] One end of the last field-effect transistor in each field-effect transistor is connected to the field-effect transistor preceding it, and the other end of the first field-effect transistor in each field-effect transistor is used to connect to the power supply.

[0085] Where N is greater than or equal to 2 and N is not equal to M, and M is the number of each field-effect transistor.

[0086] It's important to understand that the first field-effect transistor (FET) in each group refers to the FET closest to point P, and the last FET is the FET closest to point Q. In other words, the first FET is directly connected to battery cell 10, and the last FET is connected to the charger via P+.

[0087] Optional, see Figure 3 In one embodiment of this application, it further includes: a current detection module 40;

[0088] The first end of the current detection module 40 is connected to the battery cell 10, and the second end of the current detection module 40 is also used to connect to the power supply.

[0089] The controller 20 is also connected to the current detection module 40 for detecting the current in the charging circuit and / or discharging circuit.

[0090] Optionally, the charging circuit can refer to the transmission path through which current flows when the power source charges the battery cell 10. The discharging circuit can refer to the transmission path through which current flows when the battery cell 10 discharges to the outside.

[0091] Optionally, the current detection module 40 may include any possible sampling resistor, the value of which can be selected according to actual needs, and this embodiment does not limit this.

[0092] In one possible way, see Figure 4The current detection module 40 may include a sampling resistor R. In this case, the first terminal of the sampling resistor R is connected to the negative terminal of the battery cell 10, and the second terminal of the sampling resistor R is connected to the power supply.

[0093] Furthermore, the first and second ends of the sampling resistor R can be used as the acquisition terminals of the current detection module 40, respectively. In this case, the controller 20 can also be configured with two acquisition terminals connected to the first and second ends of the sampling resistor R, respectively, so that the controller 20 can detect the voltage across the sampling resistor R, and then calculate the current flowing through the sampling resistor R based on the voltage across the sampling resistor R and the resistance value of the sampling resistor R. This application embodiment does not limit this aspect.

[0094] In one possible approach, the current sensing module 40 may also include any other components capable of current sensing, such as a current sensing chip composed of a differential input amplifier and an NPN transistor. This application embodiment does not limit this.

[0095] Optionally, in one embodiment of this application, the controller 20 can also be used to control the switch assembly 30 to turn off when the detected current is greater than a preset threshold.

[0096] For example, the controller 20 can detect the current magnitude of the entire current detection module in the current detection module 40 during the charging and discharging process. When the current exceeds the preset threshold, it disconnects the corresponding switching component to provide protection.

[0097] For example, if during the charging process of battery cell 10, the controller 20 detects that the current flowing through the current detection module 40 and / or the sampling resistor R is greater than the preset threshold, then the controller 20 can output a corresponding turn-off signal to the charging field-effect transistor so that the charging field-effect transistor is turned off.

[0098] For example, if during the discharge process of battery cell 10, the controller 20 detects that the current flowing through the current detection module 40 and / or sampling resistor R is greater than the preset threshold, then the controller 20 can output a corresponding turn-off signal to the discharge field-effect transistor so that the discharge field-effect transistor is turned off.

[0099] Alternatively, in one possible approach, if the controller 20 detects that the current flowing through the current detection module 40 and / or the sampling resistor R is greater than the preset threshold, then the controller 20 can output corresponding turn-off signals to the discharge field-effect transistor and the charging field-effect transistor respectively, so that both the discharge field-effect transistor and the charging field-effect transistor are turned off.

[0100] In this way, overvoltage and / or overcurrent protection can be achieved for the reverse charging circuit and / or battery cell 10.

[0101] The preset threshold can be set by relevant technical personnel according to actual needs. Generally, the current value indicated by the preset threshold is less than the rated current of each component in the anti-reverse charging circuit.

[0102] Furthermore, the controller 20 can use the detected current to perform coulombic calculations to determine the capacity of the battery cell 10. It can also transmit the detected current to the charger for charging adjustment.

[0103] Optionally, in one embodiment of this application, the controller 20 includes a fuel gauge chip.

[0104] The fuel gauge chip may have certain functions such as identification, processing, calculation, detection, and control, but this application does not limit these functions.

[0105] Optionally, in one embodiment of this application, an electrical device includes any of the aforementioned reverse charging protection circuits.

[0106] Optionally, the electrical equipment may also include any other possible devices or components, such as display devices, input devices, audio devices, communication devices, and any other possible devices.

[0107] Optionally, the electrical device can be any possible electrical device, such as a laptop, mobile phone, tablet, drone, unmanned boat, power bank, or any device with a battery unit that can discharge to the outside and be charged by a charger. This application embodiment does not limit this.

[0108] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations 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. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0109] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A reverse charging protection circuit, characterized in that, include: Controllers and switching components; The switching assembly includes at least two field-effect transistors connected in series; One end of the switch assembly is used to connect to one end of the battery cell, and the other end of the switch assembly is used to connect to a power source; The other end of the battery unit is also used to connect to a power source; The controller is connected to both ends of the switching assembly and is also connected to the control terminal of the field-effect transistor; the controller is also connected to the battery cell. The controller controls the switching component to open when it detects that the voltages at both ends of the switching component are less than or equal to preset thresholds.

2. The anti-reverse charging circuit according to claim 1, characterized in that, The controller includes at least two voltage detection pins, which are respectively connected to the two ends of the switching assembly.

3. The anti-reverse charging circuit according to claim 1, characterized in that, The first preset threshold corresponding to the end of the switch assembly near the battery cell is greater than the second preset threshold corresponding to the end of the switch assembly used to connect to the power supply.

4. The anti-reverse charging circuit according to claim 1, characterized in that, The at least two field-effect transistors connected in series include a charging field-effect transistor and a discharging field-effect transistor; One end of the charging field-effect transistor is connected to the battery cell, and the other end of the charging field-effect transistor is connected to one end of the discharging field-effect transistor. The other end of the discharge field-effect transistor is used to connect to a power supply.

5. The anti-reverse charging circuit according to claim 4, characterized in that, The rated voltage of the charging field-effect transistor is less than a third preset threshold.

6. The anti-reverse charging circuit according to claim 1, characterized in that, The at least two field-effect transistors connected in series include three or more field-effect transistors; One end of the first field-effect transistor in each of the field-effect transistors is connected to the battery cell, and the other end of the first field-effect transistor in each of the field-effect transistors is connected to one end of the second field-effect transistor in each of the field-effect transistors. One end of the Nth field-effect transistor in each of the field-effect transistors is connected to the (N-1)th field-effect transistor in each of the field-effect transistors, and the other end of the Nth field-effect transistor in each of the field-effect transistors is connected to one end of the (N+1)th field-effect transistor in each of the field-effect transistors; where N is greater than or equal to 2 and N is not equal to M, and M is the number of each of the field-effect transistors; One end of the last field-effect transistor in each of the field-effect transistors is connected to the field-effect transistor preceding the last field-effect transistor, and the other end of the first field-effect transistor in each of the field-effect transistors is used to connect to a power supply.

7. The anti-reverse charging circuit according to claim 1, characterized in that, Also includes: Current detection module; The first end of the current detection module is connected to the battery cell, and the second end of the current detection module is also used to connect to the power supply. The controller is also connected to the current detection module for detecting the current in the charging circuit and / or discharging circuit.

8. The anti-reverse charging circuit according to claim 7, characterized in that, The controller is also used to control the switching component to turn off when the detected current is greater than a preset threshold.

9. The anti-reverse charging circuit according to claim 1, characterized in that, The controller includes a fuel gauge chip.

10. An electrical appliance, characterized in that, Includes the reverse charging protection circuit as described in any one of claims 1-9.

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