Charging protection circuit and charger

Abstract

The present invention relates to a charging protection circuit and a charger. The charging protection circuit comprises: a battery voltage sampling module connected to a battery, and a reference voltage module, a charging control module, and a switch module. The switch module is configured to connect a charging power supply and the battery. A first input terminal, a second input terminal, and an output terminal of the charging control module are respectively connected to the battery voltage sampling module, a first terminal of the reference voltage module, and the switch module. The charging control module is configured such that, when the voltage of the battery is less than a first reference voltage, the charging control module controls the switch-on and switch-off of the switch module, so that the battery is maintained in a first charging stage for charging; and when the voltage of the battery is greater than the first reference voltage, the charging control module switches the battery from the first charging stage to a second charging stage, and controls the switch-on and switch-off of the switch module, so that the battery is maintained in the second charging stage for charging. The charging protection circuit can protect a battery charging process.

Description

Charging protection circuit and charger

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on April 16, 2025, with application number 202510474706X and entitled "Charging Protection Circuit and Charger", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery charging technology, and in particular to a charging protection circuit and a charger. Background Technology

[0004] Sealed lead-acid batteries have become core energy storage devices in fields such as uninterruptible power supplies, electric vehicles, and communication base stations due to their advantages such as compact structure, maintenance-free operation, leak-proof design, high safety, and significant cost-effectiveness. However, the charging management technology for sealed lead-acid batteries has long lagged behind, falling far short of the development pace required for their widespread application.

[0005] Common charging methods have many drawbacks. On the one hand, they can lead to excessive polarization of the battery's internal plates, shortening the battery's lifespan. On the other hand, improper voltage control can easily cause overcharging, which in severe cases can even lead to thermal runaway, causing the battery to fail prematurely. Summary of the Invention

[0006] Therefore, it is necessary to provide a charging protection circuit and charger that can protect the battery during the charging process.

[0007] In a first aspect, a charging protection circuit is provided, which includes: a battery voltage sampling module connected to a battery, a reference voltage module, a charging control module, and a switching module;

[0008] The switch module is used to connect the charging power supply and the battery. The first input terminal, the second input terminal, and the output terminal of the charging control module are respectively connected to the first terminal of the battery voltage sampling module, the reference voltage module, and the switch module. When the switch module is connected to the charging power supply, the switch module conducts the charging circuit of the charging power supply and the battery based on the control of the charging control module.

[0009] The charging control module is used to control the switching module to turn on and off when the battery voltage collected by the battery voltage sampling module is less than the first reference voltage generated at the first terminal of the reference voltage module, so that the battery can maintain charging in the first charging stage.

[0010] Furthermore, when the battery voltage is greater than the first reference voltage, the battery is switched from the first charging stage to the second charging stage, and the switching module is controlled to turn on and off, so that the battery is kept charging in the second charging stage; the charging current range of the first charging stage is smaller than the charging current range of the second charging stage.

[0011] In one embodiment, the charging control module includes a charging comparison unit, a charging switching unit, and a charging sustaining unit. The first input terminal of the charging comparison unit is connected to the battery voltage sampling module, the second input terminal is connected to the first terminal of the reference voltage module, and the output terminal is connected to the first terminal of the charging switching unit. The charging sustaining unit is used to connect the second terminal of the charging switching unit to the switching module.

[0012] The charging comparison unit is used to output a first comparison signal to the charging switching unit when the battery voltage is lower than the first reference voltage, and to output a second comparison signal to the charging switching unit when the battery voltage is higher than the first reference voltage.

[0013] A charging switching unit is configured to output a first-stage charging signal to a charging sustaining unit based on a first comparison signal; and to output a second-stage charging signal to a charging sustaining unit based on a second comparison signal.

[0014] The charging sustaining unit is used to control the switching module to conduct the charging circuit between the charging power supply and the battery when the charging power supply is connected; it is also used to control the switching module to turn on and off based on the first stage charging signal to maintain the first stage charging process of the battery; and to control the switching module to turn on and off based on the second stage charging signal to maintain the second stage charging process of the battery.

[0015] In one embodiment, the charging comparator unit includes a resistor one, a resistor two, and a first operational amplifier;

[0016] The non-inverting input of the first operational amplifier is connected to the battery voltage sampling module, and the inverting input of the first operational amplifier is connected to the first terminal of the reference voltage module.

[0017] The first end of resistor one is connected to the power supply and the first end of the charging switching unit, respectively. The second end of resistor one is connected to the first end of resistor two and the second end of the charging switching unit, respectively. The second end of resistor two is connected to the output end of the first operational amplifier.

[0018] In one embodiment, the charging switching unit includes resistor three, resistor four, resistor five, resistor six, a first switching transistor, and a second operational amplifier;

[0019] The first terminals of resistor 3 and resistor 4 are connected to the power supply. The second terminal of resistor 3 is connected to the first terminal of the first switching transistor. The second terminal of the first switching transistor is connected to the output terminal of the charging comparator unit. The third terminal of the first switching transistor, the second terminal of resistor 4, and the first terminal of resistor 5 are all connected to the inverting input terminal of the second operational amplifier. Resistor 6 is used to connect the non-inverting input terminal and the output terminal of the second operational amplifier. The second terminal of resistor 5 is grounded.

[0020] In one embodiment, the charging sustaining unit includes a current limiting subunit and a switch control subunit. The first terminal of the current limiting subunit is connected to the charging switching unit. The second terminal of the current limiting subunit and the battery voltage sampling module are both connected to the first input terminal of the switch control subunit. The second input terminal of the switch control subunit is connected to the second terminal of the reference voltage module. The output terminal of the switch control subunit is connected to the switch module.

[0021] The current limiting subunit is used to pull up the input voltage of the first input terminal of the switching control subunit when the charging current is greater than the maximum current of the corresponding charging stage.

[0022] The switch control subunit is used to control the switch module to turn off when the input voltage is greater than the second reference voltage output from the second terminal of the reference voltage module, so as to disconnect the connection between the charging power supply and the battery.

[0023] In one embodiment, the current limiting subunit includes a first diode and a resistor seven, and the switch control subunit includes resistors eight, nine, and ten and a third operational amplifier.

[0024] The first end of the first diode is connected to the charging switching unit, the second end of the first diode is connected to the first end of resistor seven, the second end of resistor seven is connected to the inverting input of the third operational amplifier, and the inverting input of the third operational amplifier is connected to the battery voltage sampling module through resistor nine, the non-inverting input of the third operational amplifier is connected to the second end of the reference voltage module through resistor ten, the output of the third operational amplifier is connected to the first end of resistor eight, and the second end of resistor eight is connected to the switching module.

[0025] In one embodiment, the battery voltage sampling module includes resistor eleven, resistor twelve and resistor thirteen, the resistance value of resistor thirteen being determined based on the threshold voltage at the start of the second charging phase;

[0026] The first terminal of resistor eleven is connected to the battery. Resistor twelfth is used to connect the second terminal of resistor eleven to the first terminal of resistor thirteen. The second terminal of resistor thirteen is grounded. The common terminal of resistors twelfth and thirteenth is connected to the charging control module.

[0027] In one embodiment, the switching module includes resistor fourteen, resistor fifteen, resistor sixteen, a second switching transistor, and a third switching transistor;

[0028] The first terminal of the second switch is connected to the first terminal of resistor fourteen and the charging control module. The second terminal of the second switch is connected to the first terminal of resistor fifteen. The second terminal of resistor fifteen is connected to the first terminal of resistor sixteen and the first terminal of the third switch. The second terminal of the third switch and the second terminal of resistor sixteen are both connected to the charging power supply. The third terminal of the third switch is connected to the battery. The third terminal of the second switch and the second terminal of resistor fourteen are both grounded.

[0029] In one embodiment, the charging protection circuit further includes a charging display module, which includes a current acquisition unit, a current comparison unit, and a light-emitting diode. The input terminal of the current acquisition unit is connected to the battery, the output terminal of the current acquisition unit and the third terminal of the reference voltage module are both connected to the input terminal of the current comparison unit, and the output terminal of the current comparison unit is connected to the light-emitting diode.

[0030] When the voltage corresponding to the current acquired by the current acquisition unit is greater than the third reference voltage generated at the third terminal of the reference voltage module, the battery is in a charging state, and the current comparison unit outputs a low-level signal; the low-level signal is used to control the light-emitting diode to be in an emitting state.

[0031] When the voltage corresponding to the current acquired by the current acquisition unit is less than the third reference voltage, the battery is fully charged, and the current comparison unit outputs a high-level signal; the high-level signal is used to control the light-emitting diode to be in a non-light-emitting state.

[0032] Secondly, this application also provides a charger that includes an embodiment of any of the charging protection circuits described in the first aspect above.

[0033] The aforementioned charging protection circuit includes: a battery voltage sampling module, a reference voltage module, a charging control module, and a switching module connected to the battery. The switching module connects the charging power supply and the battery. The first input terminal, second input terminal, and output terminal of the charging control module are respectively connected to the first terminals of the battery voltage sampling module, the reference voltage module, and the switching module. When the switching module is connected to the charging power supply, it conducts the charging circuit between the charging power supply and the battery based on the control of the charging control module. The charging control module controls the switching module to turn on and off when the battery voltage sampled by the battery voltage sampling module is less than the first reference voltage generated by the first terminal of the reference voltage module, so that the battery is charged in the first charging stage. When the battery voltage is greater than the first reference voltage, it switches the battery from the first charging stage to the second charging stage and controls the switching module to turn on and off, so that the battery is charged in the second charging stage. The charging current range of the first charging stage is less than the charging current range of the second charging stage. This circuit uses an adaptive current to charge the battery at different stages of charging, which can avoid overshooting that occurs during constant voltage charging. Furthermore, by setting a reference voltage module to output a first reference voltage, the relationship between the battery voltage and the first reference voltage is determined. When the battery voltage sampled by the battery voltage sampling module is less than the first reference voltage, the charging control module controls the switch module to conduct, maintaining the battery in the first charging stage with a smaller charging current. Charging with a lower current in this stage reduces the polarization of the internal electrode materials of the battery, avoiding damage to the electrode material structure caused by high current charging, thereby significantly extending the battery's cycle life. When the battery voltage sampled by the battery voltage sampling module is greater than the first reference voltage, the charging control module controls the switch module to limit the charging power supply to maintain a charging current greater than that of the second charging stage. This reduces the charging time of the battery in the second charging stage and limits the current range during charging to protect the rechargeable battery. In other words, this charging protection circuit can rationally plan the charging current at different stages of battery charging, maximizing charging efficiency while ensuring battery safety. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the disclosed drawings without creative effort.

[0035] Figure 1 is a first schematic diagram of a charging protection circuit in one embodiment;

[0036] Figure 2 is a second schematic diagram of a charging protection circuit in one embodiment;

[0037] Figure 3 is a third schematic diagram of a charging protection circuit in one embodiment.

[0038] Explanation of reference numerals in the attached figures: 10: Charging protection circuit; 11: Battery voltage sampling module; 12: Reference voltage module; 13: Charging control module; 131: Charging comparison unit; 132: Charging switching unit; 133: Charging sustaining unit; 1331: Current limiting subunit; 1332: Switch control subunit; 14: Switch module; 15: Reverse connection protection module; 16: Charging display module; 161: Current acquisition unit; 162: Current comparison unit; 20: Battery. Detailed Implementation

[0039] 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. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0040] 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 belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0041] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0042] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0043] When used herein, the singular forms of “a,” “an,” and “ / the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0044] In one embodiment, as shown in FIG1, a charging protection circuit 10 is provided, which includes: a battery voltage sampling module 11, a reference voltage module 12, a charging control module 13, and a switch module 14 connected to the battery 20.

[0045] The switch module 14 is used to connect the charging power supply VCC1 and the battery 20. The first input terminal, the second input terminal and the output terminal of the charging control module 13 are respectively connected to the battery voltage sampling module 11, the first terminal of the reference voltage module 12 and the switch module 14. When the switch module 14 is connected to the charging power supply VCC1, the switch module 14 conducts the charging circuit of the charging power supply VCC1 and the battery 20 based on the control of the charging control module 13.

[0046] The charging control module 13 is used to control the switching module 14 to turn on and off when the battery voltage collected by the battery voltage sampling module 11 is less than the first reference voltage generated by the first terminal of the reference voltage module 12, so that the battery 20 is kept charging in the first charging stage.

[0047] Furthermore, when the battery voltage is greater than the first reference voltage, the battery 20 is switched from the first charging stage to the second charging stage, and the switching module 14 is controlled to turn on and off, so that the battery 20 is maintained in the second charging stage for charging; the charging current range of the first charging stage is less than the charging current range of the second charging stage, the charging current range of the first charging stage is denoted as the first current range, and the charging current range of the second charging stage is denoted as the second current range.

[0048] For example, the charging current range for the first charging stage can be 1 ampere (A) to 3 A, and the charging current range for the second charging stage can be 5 A to 8 A.

[0049] In this embodiment, the charging protection circuit 10 is used to connect the battery 20 to the charging power supply VCC1. When the battery 20 is connected to the charging power supply VCC1 and the charging power supply VCC1 is charging the battery 20, the charging protection circuit 10 can protect the charging process. It is understood that the charging protection circuit 10 can be set in the charger or integrated with the charging power supply VCC1.

[0050] To ensure that the charging power supply VCC1 can properly charge the battery 20, the switching module 14 in the charging protection circuit 10 connects the charging power supply VCC1 and the battery 20. When the switching module 14 is on, the charging power supply VCC1 charges the battery 20 normally; when the switching module 14 is off, the charging power supply VCC1 cannot charge the battery 20. The switching module 14 can be implemented using a switching transistor, such as a bipolar transistor or a metal-oxide-semiconductor field-effect transistor (MOS). Alternatively, it can be implemented using various types of switches, or even using switching chips.

[0051] During the charging process, battery 20 can be charged with different charging currents at different stages. This not only avoids excessive polarization of the internal plates of battery 20 but also prevents overcharging. Based on this, the charging stages of battery 20 can be divided into a first charging stage and a second charging stage. The first charging stage refers to the initial charging of battery 20, which requires a smaller charging current. The second charging stage refers to the stage after partial charging, where a larger charging current can be used. Specifically, the charging power supply VCC1 is kept at a charging current greater than that of the first charging stage. This reduces the charging time of battery 20 in the second charging stage and limits the current range during charging to protect the battery. In other words, the charging protection circuit 10 can rationally plan the charging current at different stages of battery charging, maximizing charging efficiency while ensuring battery safety. For example, battery 20 can be a lithium-ion battery, nickel-metal hydride battery, or similar type.

[0052] To enable charging at different currents at different stages, the charging protection circuit 10 also needs to include a battery voltage sampling module 11, a reference voltage module 12, and a charging control module 13. These three modules will be described in detail below.

[0053] For the battery voltage sampling module 11, its input terminal is connected to the battery 20, and its output terminal is connected to the first input terminal of the charging control module 13. During the charging process of the battery 20 by the charging power supply VCC1 when the switch module 14 is turned on, the battery voltage sampling module 11 can collect the voltage of the battery 20 in real time and input this battery voltage to the first input terminal of the charging control module 13. The battery voltage sampling module 11 can be implemented using a resistor sampling circuit or a sampling sensor circuit. With a resistor sampling circuit, the charging voltage of the battery 20 at the current moment can be determined by collecting the voltage across the resistor.

[0054] For the reference voltage module 12, the power supply VCC2 can be either the charging power supply VCC1 or a fixed power supply. The first terminal of the reference voltage module 12 is connected to the second input terminal of the charging control module 13. The function of the reference voltage module 12 is to generate a stable first reference voltage as a reference standard for charging control and input this first reference voltage to the second input terminal of the charging control module 13. Different types of batteries 20 require different reference voltage values. Therefore, a voltage regulation circuit can be set in the reference voltage module 12. The voltage regulation circuit can adjust the voltage of the power supply VCC2 based on the type of battery 20 to output a first reference voltage suitable for that type of battery 20.

[0055] For the charging control module 13, the first input terminal of the charging control module 13 is connected to the battery voltage sampling module 11 to receive the battery voltage collected by the battery voltage sampling module 11, the second input terminal is connected to the first terminal of the reference voltage module 12 to receive the first reference voltage output by the first terminal of the reference voltage module 12, and the output terminal of the charging control module 13 is connected to the switch module 14.

[0056] The charging control module 13 primarily compares the battery voltage with a first reference voltage. Based on the comparison result, it determines the charging stage of the battery 20 and controls the battery 20 to maintain that charging stage by controlling the switching module 14 to turn it on and off. Specifically, when the battery voltage is lower than the first reference voltage, it indicates that the battery voltage is low and should be charged with a smaller current. In this case, the charging control module 13 controls the battery 20 to be in the first charging stage. If the charging current of the battery 20 in the first charging stage exceeds the maximum current of that stage, causing the charging current to be too large, the charging control module 13 can control the switching module 14 to turn off, thereby reducing the charging current of the battery 20. After the switching module 14 is turned off, the charging circuit between the battery 20 and the charging power supply VCC1 is disconnected. Subsequently, based on the charging control module 13 controlling the switching module 14 to turn on, the charging circuit between the battery 20 and the charging power supply VCC1 is restored to the on state. Thus, during the first charging stage, the charging control module 13 can repeatedly control the switching module 14 to turn on and off, maintaining the charging current within a first current range. The charging current of the first charging stage is reasonably limited based on the current battery voltage to improve the battery's repeated charging life. When the battery voltage is greater than the first reference voltage, it indicates that the battery voltage is higher than in the first charging stage, and a larger current should be used for charging. At this time, the charging control module 13 can control the battery 20 to switch from the first charging stage to the second charging stage. If the charging current of the battery 20 during the second charging stage exceeds the maximum current of that stage, causing excessive charging current, the charging control module 13 can control the switching module 14 to turn off, reducing the charging current of the battery 20. After the switching module 14 is turned off, the charging circuit between the battery 20 and the charging power supply VCC1 is disconnected. The charging control module 13 then controls the switching module 14 to turn on, restoring the charging circuit between the battery 20 and the charging power supply VCC1 to the on state. Thus, in the second charging stage, the charging control module 13 can repeatedly control the switching module 14 to turn on and off, maintaining the charging current within the second current range. The charging current in the second charging stage is reasonably limited based on the current battery voltage to improve the battery's repeated charging life. In this way, the charging control module 13 can charge at different currents in different stages, with the first current range being smaller than the second current range. This limits the charging current while simultaneously accelerating the charging efficiency. The charging control module 13 can be implemented using a control chip or related circuitry including a comparator circuit.

[0057] The charging protection circuit 10 includes: a battery voltage sampling module 11, a reference voltage module 12, a charging control module 13, and a switch module 14 connected to the battery 20; the switch module 14 is used to connect the charging power supply VCC1 and the battery 20; the first input terminal, the second input terminal, and the output terminal of the charging control module 13 are respectively connected to the first terminal of the battery voltage sampling module 11, the reference voltage module 12, and the switch module 14; when the switch module 14 is connected to the charging power supply VCC1, the switch module 14 conducts the charging circuit between the charging power supply VCC1 and the battery 20 based on the control of the charging control module 13. The charging control module 13 is used to control the switching module 14 to turn on and off when the battery voltage sampled by the battery voltage sampling module 11 is less than the first reference voltage generated at the first terminal of the reference voltage module 12, so that the battery 20 is maintained in the first charging stage; and when the battery voltage is greater than the first reference voltage, to switch the battery 20 from the first charging stage to the second charging stage, and control the switching module 14 to turn on and off, so that the battery 20 is maintained in the second charging stage. The charging current range of the first charging stage is less than the charging current range of the second charging stage. This circuit charges the battery 20 with an adaptive current at different stages of charging, which can avoid the overshoot phenomenon that occurs in constant voltage charging. In addition, by setting the first reference voltage output by the reference voltage module 12, the relationship between the battery voltage and the first reference voltage is determined based on the first reference voltage. When the battery voltage sampled by the battery voltage sampling module 11 is less than the first reference voltage, the charging control module 13 controls the switching module 14 to turn on, so that the battery 20 is maintained in the first charging stage with a smaller charging current. Charging with a lower current in this stage reduces polarization of the internal electrode materials of battery 20, preventing damage to the electrode material structure caused by high-current charging, thereby significantly extending the cycle life of battery 20. When the battery voltage sampled by battery voltage sampling module 11 is greater than the first reference voltage, the charging power supply is limited to maintain a charging current greater than that of the first stage in the second charging stage. In this way, the charging time of battery 20 in the second charging stage can be reduced, while the current range during the charging process can be limited to protect the rechargeable battery. That is to say, the charging protection circuit 10 can rationally plan the charging current at different stages of battery charging, maximizing charging efficiency while ensuring the safety of battery 20.

[0058] The charging control module 13 is an important part of achieving safe charging. In one embodiment, as shown in FIG2, the charging control module 13 includes a charging comparison unit 131, a charging switching unit 132, and a charging sustaining unit 133. The first input terminal of the charging comparison unit 131 is connected to the battery voltage sampling module 11, the second input terminal is connected to the first terminal of the reference voltage module 12, and the output terminal is connected to the first terminal of the charging switching unit 132. The charging sustaining unit 133 is used to connect the second terminal of the charging switching unit 132 to the switching module 14.

[0059] The charging comparison unit 131 is used to output a first comparison signal to the charging switching unit 132 when the battery voltage is less than the first reference voltage, and to output a second comparison signal to the charging switching unit 132 when the battery voltage is greater than the first reference voltage.

[0060] The charging switching unit 132 is configured to output a first-stage charging signal to the charging sustaining unit 133 based on a first comparison signal; and to output a second-stage charging signal to the charging sustaining unit 133 based on a second comparison signal.

[0061] The charging sustaining unit 133 is used to control the switch module 14 to conduct the charging circuit between the charging power supply VCC1 and the battery 20 when the charging power supply VCC1 is connected; it also controls the switching module 14 to turn on and off based on the first stage charging signal to maintain the first stage charging process of the battery 20; and it controls the switching module 14 to turn on and off based on the second stage charging signal to maintain the second stage charging process of the battery 20.

[0062] In this embodiment, the charging control module 13 can be divided into three parts from a functional perspective: a charging comparison unit 131 for comparing the battery voltage and the first reference voltage; a charging switching unit 132 for switching the battery 20 from the first charging stage to the second charging stage according to the comparison result; and a charging maintenance unit 133 for performing current limiting control in different charging stages.

[0063] For the charging comparison unit 131, its inputs include the battery voltage collected by the battery voltage sampling module 11 and the first reference voltage generated by the first terminal of the reference voltage module 12. The battery voltage is compared with the first reference voltage, and different comparison signals are output to the charging switching unit 132 according to the comparison result. The charging comparison unit 131 can be implemented by a circuit composed of operational amplifiers and other electronic components, or by a control chip.

[0064] In one embodiment, as shown in FIG3, the charging comparison unit 131 includes a resistor R1, a resistor R2 and a first operational amplifier U1;

[0065] The non-inverting input of the first operational amplifier U1 is connected to the battery voltage sampling module 11, and the inverting input of the first operational amplifier U1 is connected to the first terminal of the reference voltage module 12.

[0066] The first end of resistor R1 is connected to the power supply VCC2 and the first end of the charging switching unit 132, respectively. The second end of resistor R1 is connected to the first end of resistor R2 and the second end of the charging switching unit 132, respectively. The second end of resistor R2 is connected to the output end of the first operational amplifier U1.

[0067] For the charging switching unit 132, its first terminal is connected to the output terminal of the charging comparison unit 131, and is used to receive corresponding comparison signals at different stages of charging the battery 20. The charging comparison unit 131 can be a logic circuit composed of multiple AND gates, OR gates, and inverters. It can also be implemented using an analog switching circuit.

[0068] In one embodiment, the charging switching unit 132 includes resistors R3, R4, R5, and R6, a first switching transistor Q1, and a second operational amplifier U2.

[0069] The first terminals of resistor 3R3 and resistor 4R4 are both connected to the power supply VCC2. The second terminal of resistor 3R3 is connected to the first terminal of the first switching transistor Q1. The second terminal of the first switching transistor Q1 is connected to the output terminal of the charging comparator unit 131. The third terminal of the first switching transistor Q1, the second terminal of resistor 4R4, and the first terminal of resistor 5R5 are all connected to the inverting input terminal of the second operational amplifier U2. Resistor 6R6 is used to connect the non-inverting input terminal and the output terminal of the second operational amplifier U2. The second terminal of resistor 5R5 is grounded.

[0070] In this embodiment, after comparing the input battery voltage and the first reference voltage using the first operational amplifier U1, the battery 20 can be determined to be in either the first charging stage or the second charging stage based on the level signal output by the first operational amplifier U1. At this time, the first switch Q1 can be turned on or off based on the level signal output by the first operational amplifier U1 to adjust the voltage at the non-inverting input of the second operational amplifier U2, thereby controlling the battery 20 to switch from the first charging stage to the second charging stage.

[0071] Specifically, when the battery voltage input to the non-inverting input of the first operational amplifier U1 is less than the first reference voltage input to the inverting input, the first operational amplifier U1 outputs a low-level signal. At this time, it can be determined that the battery 20 is in the first charging stage, i.e., slow charging. At this time, the first switching transistor Q1 is in the off state. The voltage at the inverting input of the second operational amplifier U2 is determined based on the power supply VCC2, resistor R4, and resistor R5, and the corresponding formula can be expressed as:

[0072] The voltage at the inverting input of the second operational amplifier U2 is VCC2 × (R5 / (R4+R5)).

[0073] At this time, the charging current of battery 20 in the first charging stage can be expressed as: I1=V2 / Rm, where V2 represents the voltage at the non-inverting input terminal of the second operational amplifier U2, and Rm represents the current sampling resistor of the battery.

[0074] When the battery voltage input to the non-inverting input of the first operational amplifier U1 is greater than the first reference voltage input to the inverting input, the first operational amplifier U1 outputs a high-level signal. At this time, it can be determined that the battery 20 is in the second charging stage, i.e., fast charging. At this time, the first switching transistor Q1 is in the conducting state. The voltage at the inverting input of the second operational amplifier U2 is determined based on the power supply VCC2, resistors R3, R4, and R5, and the corresponding formula can be expressed as:

[0075] The voltage at the inverting input of the second operational amplifier U2 is VCC2×(R5 / (R4||R3+R5)), where R4||R3 represents the total resistance of resistors R4 and R3 connected in parallel.

[0076] It should be noted that the voltage at the non-inverting input of the second operational amplifier U2 when the battery 20 is in the second charging stage is greater than the voltage at the non-inverting input of the second operational amplifier U2 when the battery 20 is in the first charging stage.

[0077] At this time, the charging current of battery 20 in the second charging stage can be expressed as: I2=V2 / Rm. Since the voltage V2 of the non-inverting input terminal in the second charging stage is greater than the voltage of the non-inverting input terminal in the first charging stage, then I2>I1.

[0078] The charging sustaining unit 133 includes a current limiting subunit 1331 and a switch control subunit 1332. The first terminal of the current limiting subunit 1331 is connected to the charging switching unit 132. The second terminal of the current limiting subunit 1331 and the battery voltage sampling module 11 are both connected to the first input terminal of the switch control subunit 1332. The second input terminal of the switch control subunit 1332 is connected to the second terminal of the reference voltage module 12. The output terminal of the switch control subunit 1332 is connected to the switch module 14.

[0079] The current limiting subunit 1331 is used to pull up the input voltage of the first input terminal of the switch control subunit 1332 when the charging current is greater than the maximum current of the corresponding charging stage.

[0080] The switch control subunit 1332 is used to control the switch module 14 to turn off when the input voltage is greater than the second reference voltage output from the second terminal of the reference voltage module 12, so as to disconnect the charging power supply VCC1 from the battery 20.

[0081] In one embodiment, the current limiting subunit 1331 includes a first diode D1 and a resistor R7, and the switch control subunit 1332 includes a resistor R8, a resistor R9, a resistor R10 and a third operational amplifier U3.

[0082] The first terminal of the first diode D1 is connected to the charging switching unit 132. The second terminal of the first diode D1 is connected to the first terminal of resistor R7. The second terminal of resistor R7 is connected to the inverting input terminal of the third operational amplifier U3. The inverting input terminal of the third operational amplifier U3 is connected to the battery voltage sampling module 11 through resistor R9. The non-inverting input terminal of the third operational amplifier U3 is connected to the second terminal of the reference voltage module 12 through resistor R10. The output terminal of the third operational amplifier U3 is connected to the first terminal of resistor R8. The second terminal of resistor R8 is connected to the switching module 14.

[0083] In this embodiment, regardless of whether the battery 20 is in the first charging stage or the second charging stage, when the second operational amplifier U2 outputs a high-level signal, it indicates that the charging voltage of the battery 20 exceeds the maximum voltage corresponding to that charging stage. At this time, the first diode D1 and resistor R7 pull up the battery voltage at the inverting input of the third operational amplifier U3. Once the battery voltage is greater than the second reference voltage, the third operational amplifier U3 outputs a low-level signal, and both the second switch Q2 and the third switch Q3 are not turned on. At this time, the charging current of the battery 20 will gradually decrease to 0, avoiding excessive current in the battery 20 during the charging process and improving the safety of the battery 20 charging process.

[0084] The aforementioned charging control module 13 includes a charging comparison unit 131, a charging switching unit 132, and a charging sustaining unit 133. The first input terminal of the charging comparison unit 131 is connected to the battery voltage sampling module 11, the second input terminal is connected to the first terminal of the reference voltage module 12, and the output terminal is connected to the first terminal of the charging switching unit 132. The charging sustaining unit 133 connects the second terminal of the charging switching unit 132 to the switching module 14. The charging comparison unit 131 outputs a first comparison signal to the charging switching unit 132 when the battery voltage is lower than the first reference voltage, and outputs a second comparison signal to the charging switching unit 132 when the battery voltage is higher than the first reference voltage. The circuit comprises: a charging comparison unit 131, a charging switching unit 132, and a charging sustaining unit 133; a charging switching unit 132 for outputting a first-stage charging signal to a charging sustaining unit 133 based on a first comparison signal; and a charging sustaining unit 133 for controlling a switching module 14 to conduct the charging circuit between the charging power supply VCC1 and the battery 20 when the charging power supply VCC1 is connected; controlling the switching module 14 to turn on and off based on the first-stage charging signal to maintain the first-stage charging process of the battery 20; and controlling the switching module 14 to turn on and off based on the second-stage charging signal to maintain the second-stage charging process of the battery 20. Through the coordinated operation of the charging comparison unit 131, the charging switching unit 132, and the charging sustaining unit 133, this circuit achieves slow charging with a small current in the first charging stage and fast charging with a large current in the second charging stage. This ensures that the battery 20 remains within a safe current range throughout the charging process, preventing damage to the battery from excessive current and enhancing the safety of the battery 20 during charging.

[0085] The following is a detailed description of the battery voltage sampling module 11 through an embodiment. As shown in Figure 3, the battery voltage sampling module 11 includes resistor eleven R11, resistor twelve R12 and resistor thirteen R13. The resistance value of resistor thirteen R13 is determined based on the threshold voltage at the start of the second charging stage.

[0086] The first terminal of resistor 11R11 is connected to battery 20. Resistor 12R12 is used to connect the second terminal of resistor 11R11 to the first terminal of resistor 13R13. The second terminal of resistor 13R13 is grounded. The common terminal of resistor 12R12 and resistor 13R13 is connected to charging control module 13.

[0087] In this embodiment, the battery voltage sampling module 11 includes three resistors. Resistors eleven (R11), twelve (R12), and thirteen (R13) are voltage divider resistors, primarily used to divide the collected battery voltage to prevent excessively high battery voltage from damaging subsequent electronic components. The battery voltage collected by the battery voltage sampling module 11 can be expressed as:

[0088] Sampling battery voltage = (Vbat / (R7+R8+R9))×R9

[0089] Where Vbat represents the voltage at the battery's output terminal, Vbat+ in Figure 3 represents the positive output terminal of the battery, and Vbat- represents the negative output terminal of the battery.

[0090] For different types of batteries 20 (e.g., nickel-metal hydride batteries, lithium-ion batteries, polymer batteries, etc.), their charging characteristics and the threshold voltage at the start of the second charging stage are different. Since the resistance value of resistor 13R13 can be flexibly adjusted according to the threshold voltage of different batteries, the battery voltage sampling module 11 can be widely adapted to various types of batteries.

[0091] The aforementioned battery voltage sampling module 11 includes resistors 11R11, 12R12, and 13R13. The resistance value of resistor 13R13 is determined based on the threshold voltage at the start of the second charging stage. The first terminal of resistor 11R11 is connected to the battery 20. Resistor 12R12 connects the second terminal of resistor 11R11 to the first terminal of resistor 13R13. The second terminal of resistor 13R13 is grounded. The common terminal of resistors 12R12 and 13R13 is connected to the charging control module 13. The resistance value of resistor 13R13 is determined based on the threshold voltage at the start of the second charging stage, which allows the battery voltage sampling module 11 to meet the sampling requirements of different types of batteries 20 and is applicable to voltage sampling of different types of batteries 20.

[0092] The above embodiments are all descriptions of the charging control module 13. Based on this, in order to protect the charging process of the battery 20 even when the battery 20 is reverse connected, in one embodiment, as shown in FIG3, the charging protection circuit 10 further includes a reverse connection protection module 15, which includes a second diode D2.

[0093] The first terminal of the second diode D2 is connected to the common terminal of resistors eleven (R11) and twelve (R12), and the second terminal of the second diode D2 is grounded.

[0094] In this embodiment, when the positive and negative terminals of battery 20 are reversed and the charging power supply VCC1 charges battery 20, the charging protection circuit 10 can limit the charging current through the reverse connection protection module 15 to ensure that battery 20 will not be burned out when it is reversed. Specifically, when battery 20 is reversed, based on the unidirectional conductivity of the second diode D2, the second diode D2 will prevent the reverse current from flowing from the ground terminal to the common terminal of resistor eleven R11 and resistor twelve R12. In this way, the battery voltage collected by the battery voltage sampling module 11 can be limited, so that the battery voltage is less than the first reference voltage generated by the first terminal of the reference voltage module 12. The first operational amplifier U1 outputs a low level, the first switch Q1 is not turned on, and the charging power supply VCC1 can continuously charge battery 20 with a small current. If the charging current exceeds the current threshold, that is, the voltage at the non-inverting input terminal of the second operational amplifier U2 is greater than the voltage at the inverting input terminal, the second operational amplifier U2 outputs a high-level signal to control the switch module 14 to turn off, that is, to cut off the path between the charging power supply VCC1 and the battery 20, so that the battery 20 will not be burned during the charging process, thereby realizing the reverse connection protection of the battery 20.

[0095] The aforementioned charging protection circuit 10 also includes a reverse connection protection module 15, which includes a second diode D2. The first terminal of the second diode D2 is connected to the common terminal of resistors R10 and R11, and the second terminal of the second diode D2 is grounded. By incorporating the reverse connection protection module 15, which includes a diode, the risk of component damage caused by reverse current can be effectively avoided, ensuring that the battery 20 will not be burned out under reverse connection conditions, thus extending the service life of the battery 20.

[0096] The following is a detailed description of the switching module 14 through an embodiment. As shown in Figure 3, the switching module 14 includes resistor fourteen R14, resistor fifteen R15, resistor sixteen R16, second switch Q2, and third switch Q3.

[0097] The first terminal of the second switch Q2 is connected to the first terminal of resistor fourteen R14 and the charging control module 13. The second terminal of the second switch Q2 is connected to the first terminal of resistor fifteen R15. The second terminal of resistor fifteen R15 is connected to the first terminal of resistor sixteen R16 and the first terminal of the third switch Q3. The second terminal of the third switch Q3 and the second terminal of resistor sixteen R16 are both connected to the charging power supply VCC1. The third terminal of the third switch Q3 is connected to the battery 20. The third terminal of the second switch Q2 and the second terminal of resistor fourteen R14 are both grounded.

[0098] When the charging power supply VCC1 is connected to the charging protection circuit 10, the third switch Q3 is not turned on, the battery voltage input to the inverting input of the third operational amplifier U3 is 0V, and the second reference voltage input to the non-inverting input is greater than the battery voltage. Therefore, the output of the third operational amplifier U3 outputs a high-level signal. At this time, the second switch Q2 is closed, and the third switch Q3 is turned on, allowing the charging power supply VCC1 to charge the battery 20. During normal charging of the battery 20, the battery voltage is less than the second reference voltage, and the third operational amplifier U3 continuously outputs a high-level signal, while both the second and third switches Q2 and Q3 are turned on. When the battery 20 is abnormally charged (excessive charging current), the battery voltage is greater than the second reference voltage, the third operational amplifier U3 outputs a low-level signal, and both the second and third switches Q2 and Q3 are turned off. The charging current of the battery 20 gradually decreases to 0. When the charging current of battery 20 is 0, the battery voltage is less than the second reference voltage. At this time, the second switch Q2 and the third switch Q3 can continue to be turned on. This process is repeated so that battery 20 can be charged with different charging currents at different charging stages.

[0099] The aforementioned switch module 14 includes resistors R14, R15, and R16, a second switch Q2, and a third switch Q3. The first terminal of the second switch Q2 is connected to the first terminal of resistor R14 and the charging control module 13. The second terminal of the second switch Q2 is connected to the first terminal of resistor R15. The second terminal of resistor R15 is connected to the first terminal of resistor R16 and the first terminal of the third switch Q3. The second terminals of the third switch Q3 and resistor R16 are both connected to the charging power supply VCC1. The third terminal of the third switch Q3 is connected to the battery 20. The third terminals of the second switch Q2 and resistor R14 are both grounded. This circuit, by using two switches, can conduct during charging, ensuring that the charging power supply VCC1 can charge the battery 20. Furthermore, the switch module 14, through its connection with the current-limiting subunit 1331, uses the switching action of the two switches to prevent excessive charging current from damaging the battery 20, thus ensuring the safety of the charging process.

[0100] As shown in Figure 3, the reference voltage module 12 includes resistor 17R17, resistor 18R18 and resistor 19R19. Resistor 17R17 is a sliding rheostat, and its resistance value can be adjusted according to different battery 20 requirements.

[0101] The first terminal of resistor 17R17 is connected to the power supply VCC2. The second terminal of resistor 17R17 is connected to the first terminal of resistor 18R18 and the inverting input terminal of the first operational amplifier U1. The second terminal of resistor 18R18 is connected to the first terminal of resistor 19R19. The second terminal of resistor 19R19 is grounded.

[0102] For the reference voltage module 12, the reference voltage module 12 inputs a first reference voltage to the inverting input terminal of the first operational amplifier U1 through the common terminal of resistors 17R17 and 18R18. Resistor 10 is connected to the third terminal of resistor 17R17, and the reference voltage module 12 inputs a second reference voltage to the non-inverting input terminal of the third operational amplifier U3 through resistors 17R17 and 10R10. The reference voltage module 12 can also input a third reference voltage to the non-inverting input terminal of the fourth operational amplifier U4 through the common terminal of resistors 18R18 and 19R19.

[0103] It should be noted that the power supply VCC2 can be provided directly by the power source or obtained by voltage conversion from the charging power supply VCC1. Referring to Figure 3, for AC power, a transformer T can be connected between AC+ and AC-. The transformer T transforms the AC power supply voltage, resulting in two branches. In one branch, the output of transformer T is connected to the switching module 14 in the charging protection circuit 10 via the third diode D3, the fourth diode D4, and the first capacitor C1. The third diode D3 and the fourth diode D4 form a rectifier circuit, converting the AC power supplied by AC power into DC power. The first capacitor C1 is used for filtering; in the figure, it is connected to the second terminal of resistor R16 and the second terminal of the third switching transistor. In the other branch, the fifth diode D5, the second capacitor C2, the third capacitor C3, and the voltage regulator chip U5 form a reference voltage circuit to provide power supply VCC2 for different modules (different modules refer to the circuit structure). For example, the required voltage for power supply VCC2 is 5V, 8V, etc. It should be noted that the voltage regulator chip U5 includes three ports: a, b, and c. Port a is connected to the fifth diode D5 and the second capacitor C2, respectively. Port b is connected to the power supply VCC2 and the third capacitor C3, respectively. Port c is grounded. Port a is the input voltage port (LINEVOLTAGE), port b is the voltage regulator (VRGE), and port c is the ground terminal (COMMON).

[0104] In one embodiment, as shown in FIG2, the charging protection circuit 10 further includes a charging display module 16. The charging display module 16 includes a current acquisition unit 161, a current comparison unit 162, and a light-emitting diode (LED). The input terminal of the current acquisition unit 161 is connected to the battery 20. The output terminal of the current acquisition unit 161 and the third terminal of the reference voltage module 12 are both connected to the input terminal of the current comparison unit 162. The output terminal of the current comparison unit 162 is connected to the light-emitting diode (LED).

[0105] When the voltage corresponding to the current acquired by the current acquisition unit 161 is greater than the third reference voltage generated at the third terminal of the reference voltage module 12, the battery 20 is in a charging state, and the current comparison unit 162 outputs a low-level signal; the low-level signal is used to control the light-emitting diode (LED) to be in an emitting state.

[0106] When the voltage corresponding to the current acquired by the current acquisition unit 161 is less than the third reference voltage, the battery 20 is fully charged, and the current comparison unit 162 outputs a high-level signal; the high-level signal is used to control the light-emitting diode (LED) to be in a non-light-emitting state.

[0107] In this embodiment, the current acquisition unit 161 includes a current sampling resistor Rm, and the current comparison unit 162 includes a fourth operational amplifier U4 and a resistor R20. The first end of the current sampling resistor Rm is connected to the non-inverting input of the second operational amplifier U2 and the negative terminal of the battery 20. The second end of the current sampling resistor Rm is connected to the inverting input of the fourth operational amplifier U4. The non-inverting input of the fourth operational amplifier U4 is connected to the common terminal of resistors R18 and R19. The output terminal of the fourth operational amplifier U4 is connected to the first end of resistor R20. The second end of resistor R20 is connected to the first end of a light-emitting diode (LED), and the second end of the LED is connected to the power supply VCC2.

[0108] If the input voltage at the non-inverting input terminal of the fourth operational amplifier U4 is greater than the input voltage at the inverting input terminal, the fourth operational amplifier U4 outputs a high-level signal. The third reference voltage generated at the third terminal of the reference voltage module 12 is greater than the voltage corresponding to the current collected by the current acquisition unit 161. At this time, the battery 20 is fully charged, and the light-emitting diode LED is in a non-light-emitting state.

[0109] If the input voltage at the non-inverting input terminal of the fourth operational amplifier U4 is less than the input voltage at the inverting input terminal, the fourth operational amplifier U4 outputs a low-level signal. The third reference voltage generated at the third terminal of the reference voltage module 12 is less than the voltage corresponding to the current collected by the current acquisition unit 161. At this time, when the battery 20 is in the normal charging process (including when the battery 20 is in the first charging stage and the second charging stage), the light-emitting diode LED is in the light-emitting state.

[0110] The charging protection circuit 10 also includes a charging display module 16. The charging display module 16 includes a current acquisition unit 161, a current comparison unit 162, and a light-emitting diode (LED). The input terminal of the current acquisition unit 161 is connected to the battery 20. The output terminal of the current acquisition unit 161 and the third terminal of the reference voltage module 12 are both connected to the input terminal of the current comparison unit 162. The output terminal of the current comparison unit 162 is connected to the LED. When the voltage corresponding to the current acquired by the current acquisition unit 161 is greater than the third reference voltage generated by the third terminal of the reference voltage module 12, the battery 20 is in a charging state, and the current comparison unit 162 outputs a low-level signal. The low-level signal is used to control the LED to be in an emitting state. When the voltage corresponding to the current acquired by the current acquisition unit 161 is less than the third reference voltage, the battery 20 is in a fully charged state, and the current comparison unit 162 outputs a high-level signal. The high-level signal is used to control the LED to be in an off-light state. By setting up a charging display module 16, the current in the battery 20 is collected by the current acquisition unit 161 in the charging display module 16, and the voltage corresponding to the collected current is compared with the third reference voltage. Based on the comparison result, it can be accurately determined whether the battery 20 is fully charged. Then, the on / off state of the light-emitting diode (LED) in the charging display module 16 is used to show the user whether the battery 20 is fully charged, so that the user can understand the charging status of the battery 20 more intuitively.

[0111] The working process of the charging protection circuit 10 will be described in detail below through a specific embodiment.

[0112] When AC power is connected, the third switch Q3 is not turned on, and the battery voltage input to the inverting input of the third operational amplifier U3 is 0V. The output of the third operational amplifier U3 outputs a high level, which turns on both the second and third switches Q2 and Q3. At this time, the AC power is rectified by the transformer T to form a charging power supply VCC1 to charge battery 20. The charging voltage of battery 20 is relatively low, and battery 20 is in the first charging stage. Simultaneously, the fourth operational amplifier U4 outputs a low level signal, and the light-emitting diode (LED) is in an illuminated state.

[0113] When battery 20 is in the first charging stage, the battery voltage input to the inverting input of the third operational amplifier U3 is less than the second reference voltage input to the non-inverting input, and the second switch Q2 and the third switch Q3 are in the conducting state. The first reference voltage input to the inverting input of the first operational amplifier U1 is greater than the battery voltage input to the non-inverting input, so the first operational amplifier U1 outputs a low-level signal, and the first switch Q1 is not working. At this time, the voltage at the inverting input of the second operational amplifier U2 is VCC2×(R5 / (R4+R5)). For the current limiting process in the first charging stage, when the charging current of battery 20 is higher than the maximum current in the first charging stage, the voltage at the non-inverting input of the second operational amplifier U2 is greater than the voltage at the inverting input, and a high-level signal is output. This high-level signal will pull up the battery voltage at the inverting input of the third operational amplifier U3. Thus, the output of the third operational amplifier U3 outputs a low-level signal. When both the second switch Q2 and the third switch Q3 are turned off, and the charging current of battery 20 gradually decreases to 0, the battery voltage input to the inverting input of the third operational amplifier U3 is less than the second reference voltage input to the non-inverting input, and the second switch Q2 and the third switch Q3 are turned on. This process repeats, thus limiting the charging current of battery 20 during the first charging stage.

[0114] When the battery voltage gradually rises to a certain voltage threshold (determined by the resistance value of resistor R13), the battery voltage input to the inverting input of the third operational amplifier U3 is less than the second reference voltage input to the non-inverting input, and the second and third switches Q2 and Q3 are turned on. The first reference voltage input to the inverting input of the first operational amplifier U1 is less than the battery voltage input to the non-inverting input, so the first operational amplifier U1 outputs a high-level signal, and the first switch Q1 is turned on. At this time, the voltage at the inverting input of the second operational amplifier U2 is VCC2 × (R5 / (R4||R3+R5)). For the current-limiting process in the second charging stage, when the charging current of battery 20 is higher than the maximum current in the second charging stage, the voltage at the non-inverting input of the second operational amplifier U2 is greater than the voltage at the inverting input, resulting in a high-level output signal. This high-level signal will pull up the battery voltage at the inverting input of the third operational amplifier U3, thus causing the output of the third operational amplifier U3 to be a low-level signal. Both the second switch Q2 and the third switch Q3 are turned off. After the charging current of battery 20 gradually decreases to 0, the battery voltage input to the inverting input of the third operational amplifier U3 is less than the second reference voltage input to the non-inverting input, and the second switch Q2 and the third switch Q3 are turned on. By repeating this process, the charging current of battery 20 in the second charging stage can be limited.

[0115] After the battery 20 completes the first and second charging stages, and is fully charged, the light-emitting diode (LED) switches from the emitting state to the non-emitting state.

[0116] It should be noted that the third reference voltage output by the reference voltage module 12 is greater than the second reference voltage, and the second reference voltage is greater than the first reference voltage.

[0117] Additionally, referring to Figure 3, Vbat represents the positive output terminal of the battery, and Vbat- represents the negative output terminal of the battery. A fuse FU and a sixth diode D6 can also be installed between the resistor R11 in the battery voltage sampling module 11, the third terminal of the third switch Q3 in the switching module 14, and the positive output terminal of the battery.

[0118] When a short circuit occurs in the charging protection circuit 10 or the battery connected to it, the short circuit current will increase rapidly and instantaneously. The fuse FU will melt rapidly under the high temperature generated by the short circuit current, thereby cutting off the connection between the charging protection circuit 10 and the battery 20, preventing the short circuit current from causing serious damage to the battery and the circuit components in the charging protection circuit 10, and avoiding safety accidents such as overheating, fire or even explosion caused by the short circuit.

[0119] In another embodiment, a charger is also provided, which includes the charging protection circuit 10 involved in the above embodiments.

[0120] Optionally, the charger can be fixed in a designated location and kept connected to the charging power source VCC1. This is similar to the charging stations for new energy vehicles. Alternatively, the charger can also be a portable charger, similar to chargers for electric vehicles, mobile phones, etc.

[0121] The above description provides a further detailed explanation of the embodiments of this application in conjunction with specific / preferred implementation methods. It should not be construed that the specific implementation of the embodiments of this application is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the embodiments of this application, and such substitutions or modifications should be considered within the protection scope of the embodiments of this application. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the described specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; however, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A charging protection circuit, wherein, The charging protection circuit includes: a battery voltage sampling module, a reference voltage module, a charging control module, and a switch module connected to the battery; The switch module is used to connect the charging power supply and the battery. The first input terminal, the second input terminal and the output terminal of the charging control module are respectively connected to the battery voltage sampling module, the first terminal of the reference voltage module and the switch module. When the switch module is connected to the charging power supply, the switch module conducts the charging circuit of the charging power supply and the battery based on the control of the charging control module. The charging control module is used to control the switching module to turn on and off when the battery voltage collected by the battery voltage sampling module is less than the first reference voltage generated at the first terminal of the reference voltage module, so that the battery maintains charging in the first charging stage. Furthermore, when the battery voltage is greater than the first reference voltage, the battery is switched from the first charging stage to the second charging stage, and the switching module is controlled to turn on and off, so that the battery is maintained in the second charging stage for charging; the charging current range of the first charging stage is smaller than the charging current range of the second charging stage.

2. The circuit according to claim 1, wherein, The charging control module includes a charging comparison unit, a charging switching unit, and a charging sustaining unit. The first input terminal of the charging comparison unit is connected to the battery voltage sampling module, the second input terminal is connected to the first terminal of the reference voltage module, and the output terminal is connected to the first terminal of the charging switching unit. The charging sustaining unit is used to connect the second terminal of the charging switching unit to the switching module. The charging comparison unit is configured to output a first comparison signal to the charging switching unit when the battery voltage is less than the first reference voltage, and to output a second comparison signal to the charging switching unit when the battery voltage is greater than the first reference voltage. The charging switching unit is configured to output a first-stage charging signal to the charging sustaining unit based on the first comparison signal; and to output a second-stage charging signal to the charging sustaining unit based on the second comparison signal. The charging sustaining unit is used to control the switching module to conduct the charging circuit of the charging power supply and the battery when the charging power supply is connected; it is also used to control the switching module to conduct and turn off based on the first stage charging signal, so as to maintain the first stage charging process of the battery. Furthermore, based on the second-stage charging signal, the switching module is controlled to turn on and off in order to maintain the second-stage charging process of the battery.

3. The circuit according to claim 2, wherein, The charging comparison unit includes resistor one, resistor two, and a first operational amplifier; The non-inverting input of the first operational amplifier is connected to the battery voltage sampling module, and the inverting input of the first operational amplifier is connected to the first terminal of the reference voltage module. The first end of resistor one is connected to the power supply and the first end of the charging switching unit, the second end of resistor one is connected to the first end of resistor two and the second end of the charging switching unit, and the second end of resistor two is connected to the output end of the first operational amplifier.

4. The circuit according to claim 2, wherein, The charging switching unit includes resistor three, resistor four, resistor five, resistor six, a first switching transistor, and a second operational amplifier; The first end of resistor three and the first end of resistor four are both connected to the power supply. The second end of resistor three is connected to the first end of the first switching transistor. The second end of the first switching transistor is connected to the output end of the charging comparator unit. The third end of the first switching transistor, the second end of resistor four, and the first end of resistor five are all connected to the inverting input end of the second operational amplifier. Resistor six is ​​used to connect the non-inverting input end and the output end of the second operational amplifier. The second end of resistor five is grounded.

5. The circuit according to any one of claims 2-4, wherein, The charging sustaining unit includes a current limiting subunit and a switch control subunit. The first terminal of the current limiting subunit is connected to the charging switching unit. The second terminal of the current limiting subunit and the battery voltage sampling module are both connected to the first input terminal of the switch control subunit. The second input terminal of the switch control subunit is connected to the second terminal of the reference voltage module. The output terminal of the switch control subunit is connected to the switch module. The current limiting subunit is used to pull up the input voltage of the first input terminal of the switch control subunit when the charging current is greater than the maximum current of the corresponding charging stage. The switch control subunit is used to control the switch module to turn off when the input voltage is greater than the second reference voltage output from the second terminal of the reference voltage module, so as to disconnect the connection between the charging power supply and the battery.

6. The circuit according to claim 5, wherein, The current limiting subunit includes a first diode and a resistor seven, and the switch control subunit includes resistors eight, nine, and ten and a third operational amplifier; The first end of the first diode is connected to the charging switching unit, the second end of the first diode is connected to the first end of the resistor seven, the second end of the resistor seven is connected to the inverting input of the third operational amplifier, and the inverting input of the third operational amplifier is connected to the battery voltage sampling module through the resistor nine, the non-inverting input of the third operational amplifier is connected to the second end of the reference voltage module through the resistor ten, the output of the third operational amplifier is connected to the first end of the resistor eight, and the second end of the resistor eight is connected to the switching module.

7. The circuit according to any one of claims 1-4, wherein, The battery voltage sampling module includes resistor eleven, resistor twelve and resistor thirteen, and the resistance value of resistor thirteen is determined based on the threshold voltage at the start of the second charging stage; The first end of resistor eleven is connected to the battery, resistor twelf is used to connect the second end of resistor eleven to the first end of resistor thirteen, the second end of resistor thirteen is grounded, and the common end of resistor twelf and resistor thirteen is connected to the charging control module.

8. The circuit according to any one of claims 1-4, wherein, The switching module includes resistor fourteen, resistor fifteen, resistor sixteen, a second switching transistor, and a third switching transistor; The first end of the second switch is connected to the first end of the resistor fourteen and the charging control module. The second end of the second switch is connected to the first end of the resistor fifteen. The second end of the resistor fifteen is connected to the first end of the resistor sixteen and the first end of the third switch. The second end of the third switch and the second end of the resistor sixteen are both connected to the charging power supply. The third end of the third switch is connected to the battery. The third end of the second switch and the second end of the resistor fourteen are both grounded.

9. The circuit according to any one of claims 1-4, wherein, The charging protection circuit also includes a charging display module, which includes a current acquisition unit, a current comparison unit, and a light-emitting diode. The input terminal of the current acquisition unit is connected to the battery, the output terminal of the current acquisition unit and the third terminal of the reference voltage module are both connected to the input terminal of the current comparison unit, and the output terminal of the current comparison unit is connected to the light-emitting diode. When the voltage corresponding to the current acquired by the current acquisition unit is greater than the third reference voltage generated at the third terminal of the reference voltage module, the battery is in a charging state, and the current comparison unit outputs a low-level signal; the low-level signal is used to control the light-emitting diode to be in an emitting state. When the voltage corresponding to the current acquired by the current acquisition unit is less than the third reference voltage, the battery is fully charged, and the current comparison unit outputs a high-level signal; the high-level signal is used to control the light-emitting diode to be in a non-light-emitting state.

10. A charger, wherein, The charger includes the charging protection circuit described in any one of claims 1-9.

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