Charging protection circuit and charger

Abstract

The present invention relates to a charging protection circuit and a charger. The charging protection circuit includes: a battery voltage sampling module connected to a battery, a reference voltage module, a charging control module, and a switch module; the switch module is used to connect a charging power source and the battery, and the first input end, second input end, and output end of the charging control module are respectively connected to the battery voltage sampling module, the first end of the reference voltage module, and the switch module; the charging control module is used to control the conduction and cutoff of the switch module when the battery voltage is less than a first reference voltage, so that the battery is maintained in the first charging stage for charging; and 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 conduction and cutoff of the switch module are controlled so that the battery is maintained in the second charging stage for charging. The charging protection circuit can protect the battery during the charging process.

Description

Technical Field

[0001] The present application relates to the technical field of battery charging, and in particular to a charging protection circuit and a charger. Background Art

[0002] Sealed lead-acid batteries, due to their compact structure, maintenance-free design, leak-proof design, high safety, and significant cost-effectiveness, have become core energy storage devices in uninterruptible power supplies, electric vehicles, communication base stations, and other fields. However, charge management technology for sealed lead-acid batteries has long lagged far behind the development of their widespread application.

[0003] Common charging methods have many drawbacks. On the one hand, they can lead to excessive polarization of the battery plates, shortening the battery life. On the other hand, improper voltage control can easily lead to overcharging, and in severe cases, even thermal runaway, causing premature battery failure. Summary of the Invention

[0004] Based on this, it is necessary to provide a charging protection circuit and a charger that can protect the battery charging process.

[0005] In a first aspect, a charging protection circuit is provided, the charging protection circuit comprising: a battery voltage sampling module connected to a battery, a reference voltage module, a charging control module, and a switch module;

[0006] 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, under the control of the charging control module, conducts the charging circuit between the charging power supply and the battery.

[0007] a charging control module, configured to control the switching module to be turned on and off when the battery voltage collected by the battery voltage sampling module is lower than the first reference voltage generated by the first end of the reference voltage module, so that the battery is charged in the first charging stage;

[0008] 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 on and off of the switch module is controlled 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.

[0009] In one embodiment, the charging control module includes a charging comparison unit, a charging switching unit, and a charging maintenance 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 maintenance unit is used to connect the second terminal of the charging switching unit to the switch module.

[0010] a charging comparison unit, configured to output a first comparison signal to the charging switching unit when the battery voltage is less than the first reference voltage; and output a second comparison signal to the charging switching unit when the battery voltage is greater than the first reference voltage;

[0011] a charging switching unit configured to output a first-stage charging signal to the charging maintaining unit based on the first comparison signal; and output a second-stage charging signal to the charging maintaining unit based on the second comparison signal;

[0012] The charging maintenance unit is used to control the switch module to conduct the charging power supply and the charging circuit of the battery when the charging power supply is connected; it is also used to control the conduction and cutoff of the switch module based on the first-stage charging signal to maintain the first-stage charging process of the battery; and, based on the second-stage charging signal, control the conduction and cutoff of the switch module to maintain the second-stage charging process of the battery.

[0013] In one embodiment, the charge comparison unit includes a resistor 1, a resistor 2, and a first operational amplifier;

[0014] The non-inverting input terminal of the first operational amplifier is connected to the battery voltage sampling module, and the inverting input terminal of the first operational amplifier is connected to the first terminal of the reference voltage module;

[0015] The first end of resistor 1 is connected to the power supply and the first end of the charging switching unit respectively, the second end of resistor 1 is connected to the first end of resistor 2 and the second end of the charging switching unit respectively, and the second end of resistor 2 is connected to the output end of the first operational amplifier.

[0016] In one embodiment, the charging switching unit includes a resistor 3, a resistor 4, a resistor 5, a resistor 6, a first switch tube, and a second operational amplifier;

[0017] The first end of resistor 3 and the first end of resistor 4 are both connected to the power supply, the second end of resistor 3 is connected to the first end of the first switching tube, the second end of the first switching tube is connected to the output end of the charging comparison unit, the third end of the first switching tube, the second end of resistor 4, and the first end of resistor 5 are all connected to the inverting input end of the second operational amplifier, resistor 6 is used to connect the non-inverting input end and the output end of the second operational amplifier, and the second end of resistor 5 is grounded.

[0018] In one embodiment, the charge maintenance unit includes a current limiting subunit and a switch control subunit, wherein a first end of the current limiting subunit is connected to the charge switching unit, a second end of the current limiting subunit and a battery voltage sampling module are both connected to a first input end of the switch control subunit, a second input end of the switch control subunit is connected to a second end of the reference voltage module, and an output end of the switch control subunit is connected to the switch module;

[0019] The current limiting subunit is used to increase 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;

[0020] The switch control subunit is used to control the switch module to be turned off when the input voltage is greater than the second reference voltage output by the second end of the reference voltage module, so as to cut off the connection between the charging power supply and the battery.

[0021] In one embodiment, the current limiting subunit includes a first diode and a resistor seven, and the switch control subunit includes a resistor eight, a resistor nine, a resistor ten, and a third operational amplifier;

[0022] 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 end of the third operational amplifier, and the inverting input end of the third operational amplifier is connected to the battery voltage sampling module through resistor nine, the non-inverting input end of the third operational amplifier is connected to the second end of the reference voltage module through resistor ten, the output end 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 switch module.

[0023] In one embodiment, the battery voltage sampling module includes a resistor 11, a resistor 12, and a resistor 13, and the resistance value of the resistor 13 is determined based on the threshold voltage at the start of the second charging stage;

[0024] The first end of the resistor 11 is connected to the battery, the resistor 12 is used to connect the second end of the resistor 11 and the first end of the resistor 13, the second end of the resistor 13 is grounded, and the common end of the resistor 12 and the resistor 13 is connected to the charging control module.

[0025] In one embodiment, the switch module includes a resistor 14, a resistor 15, a resistor 16, a second switch tube and a third switch tube;

[0026] The first end of the second switch tube is connected to the first end of resistor 14 and the charging control module, the second end of the second switch tube is connected to the first end of resistor 15, the second end of resistor 15 is respectively connected to the first end of resistor 16 and the first end of the third switch tube, the second end of the third switch tube and the second end of resistor 16 are both connected to the charging power supply, the third end of the third switch tube is connected to the battery, and the third end of the second switch tube and the second end of resistor 14 are both grounded.

[0027] 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 end of the current acquisition unit is connected to the battery, the output end of the current acquisition unit and the third end of the reference voltage module are both connected to the input end of the current comparison unit, and the output end of the current comparison unit is connected to the light-emitting diode.

[0028] When the voltage corresponding to the current collected by the current collection unit is greater than the third reference voltage generated by 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 a light-emitting state;

[0029] When the voltage corresponding to the current collected by the current collection 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-luminous state.

[0030] In a second aspect, the present application further provides a charger, which includes an embodiment of any charging protection circuit in the first aspect.

[0031] The charging protection circuit includes: a battery voltage sampling module connected to the battery, a reference voltage module, a charging control module, and a switch module; the switch module is used to connect the charging power supply and the battery, and the first input terminal, second input terminal, and 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, under the control of the charging control module, conducts the charging circuit between the charging power supply and the battery; the charging control module is used to control the conduction and cutoff of the switch module 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 remains in the first charging stage; and 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 switch module is controlled to be conducted and cutoff so that the battery remains 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. The circuit charges with adaptive current at different stages of battery charging, which can avoid the overshoot phenomenon caused by constant voltage charging. Furthermore, by setting the reference voltage module to output a first reference voltage, 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 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 lower charging current. Charging with a lower current during this stage can reduce polarization of the battery's internal electrode materials and prevent structural damage to the electrode materials 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 a second charging stage current greater than the first charging stage current. This reduces the charging time of the battery in the second charging stage and also limits the current range during the charging process 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0033] Figure 1 is a first schematic diagram of a charging protection circuit in one embodiment;

[0034] Figure 2 is a second schematic diagram of a charging protection circuit in one embodiment;

[0035] Figure 3 FIG. 3 is a third schematic diagram of a charging protection circuit in one embodiment.

[0036] Description of reference numerals:

[0037] 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 maintenance 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 DESCRIPTION

[0038] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0040] It will be 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 a first element from another element. For example, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor without departing from the scope of this application. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0041] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0042] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0043] In one embodiment, Figure 1 As shown, a charging protection circuit 10 is provided, which includes: a battery voltage sampling module 11 connected to a battery 20, a reference voltage module 12, a charging control module 13 and a switch module 14;

[0044] 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, under the control of the charging control module 13, conducts the charging circuit between the charging power supply VCC1 and the battery 20.

[0045] The charging control module 13 is configured to control the switching module 14 to be turned on and off when the battery voltage collected by the battery voltage sampling module 11 is lower than the first reference voltage generated by the first end of the reference voltage module 12, so that the battery 20 is charged in the first charging stage;

[0046] 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 switch module 14 is controlled to be 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 smaller than the charging current range of the second charging stage, and the charging current range of the first charging stage is recorded as the first current range, and the charging current range of the second charging stage is recorded as the second current range.

[0047] For example, the charging current range of the first charging stage may be 1 ampere (A)-3A, and the charging current range of the second charging stage may be 5A-8A.

[0048] In the embodiment of the present application, 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 used to charge the battery 20, the charging protection circuit 10 can protect the charging process. It is understood that the charging protection circuit 10 can be provided in the charger or integrated with the charging power supply VCC1.

[0049] To ensure that the charging power supply VCC1 can properly charge the battery 20, the switch module 14 in the charging protection circuit 10 is used to connect the charging power supply VCC1 to the battery 20. When the switch module 14 is on, the charging power supply VCC1 can properly charge the battery 20; when the switch module 14 is off, the charging power supply VCC1 cannot charge the battery 20. The switch module 14 can be implemented using a switching transistor, such as a triode or a metal oxide semiconductor field effect transistor (MOS). Alternatively, it can be implemented using various types of switches, or even using a switching chip.

[0050] During the charging process, the battery 20 can be charged at different charging currents at different stages, which not only avoids transition polarization of the internal plates of the battery 20, but also avoids overcharge. Based on this, the charging stage of the 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 the battery 20, and this stage requires charging with a smaller charging current. The second charging stage refers to the stage where partial charging has been completed, and this stage can be charged with a larger charging current, that is, the charging power supply VCC1 is limited to maintain a charging current greater than that of the first charging stage in the second charging stage; this can reduce the charging time of the battery 20 in the second charging stage, and at the same time, the current range during the charging process can be limited to protect the rechargeable battery. In other words, the charging protection circuit 10 can reasonably plan the charging current at different stages of battery charging, maximizing the charging efficiency while ensuring battery safety. For example, the battery 20 can be a lithium-ion battery, a nickel-metal hydride battery, or the like.

[0051] In order to realize charging at different currents at different stages, the charging protection circuit 10 also needs to be provided with a battery voltage sampling module 11, a reference voltage module 12 and a charging control module 13. These three modules are introduced one by one below.

[0052] For the battery voltage sampling module 11, the input end of the battery voltage sampling module 11 is connected to the battery 20, and the output end of the battery voltage sampling module 11 is connected to the first input end of the charging control module 13. When the switch module 14 is turned on and the charging power supply VCC1 is charging the battery 20, the battery voltage sampling module 11 can collect the voltage of the battery 20 at the current moment in real time and input the battery voltage to the first input end of the charging control module 13. The battery voltage sampling module 11 can be implemented by a resistor sampling circuit or a sampling sensor circuit. For the resistor sampling circuit, the charging voltage of the battery 20 at the current moment can be determined by collecting the voltage across the resistor.

[0053] For the reference voltage module 12, its power supply VCC2 can be the charging power supply VCC1 or a fixed power source. A first terminal of the reference voltage module 12 is connected to a 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 provided within the reference voltage module 12. This 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 appropriate for that type of battery 20.

[0054] For the charging control module 13, a first input end of the charging control module 13 is connected to the battery voltage sampling module 11 for receiving the battery voltage collected by the battery voltage sampling module 11, a second input end is connected to the first end of the reference voltage module 12 for receiving the first reference voltage output by the first end of the reference voltage module 12, and an output end of the charging control module 13 is connected to the switch module 14.

[0055] 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 switching module 14 to maintain the battery 20 in that charging stage by turning it on and off. Specifically, when the battery voltage is lower than the first reference voltage, indicating that the battery voltage is low and charging should be performed with a lower current, the charging control module 13 controls the battery 20 to enter the first charging stage. While the battery 20 is in the first charging stage, if the charging current of the battery 20 during the first charging stage exceeds the maximum current of that stage, resulting in an excessive charging current, 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 source VCC1 is disconnected. Subsequently, when the switching module 14 is turned on under the control of the charging control module 13, the charging circuit between the battery 20 and the charging power source VCC1 is restored to its conductive state. In this way, during the first charging stage, the charging control module 13 can repeatedly control the switch module 14 to be turned on and off, maintaining the charging current within a first current range. The charging current in the first charging stage is appropriately limited based on the current battery voltage to extend the battery's reusable service life. When the battery voltage is greater than the first reference voltage, indicating that the battery voltage is higher than in the first charging stage and charging should be performed at a higher current, 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 for that stage, resulting in an excessive charging current, the charging control module 13 can control the switch module 14 to be turned off to reduce the charging current of the battery 20. After the switch module 14 is turned off, the charging circuit between the battery 20 and the charging power source VCC1 is disconnected. The charging control module 13 controls the switch module 14 to be turned on, and the charging circuit between the battery 20 and the charging power source VCC1 is restored to its conductive state. Thus, during the second charging phase, the charging control module 13 can repeatedly control the on and off switching of the switch module 14 to maintain the charging current within the second current range. The charging current of the second charging phase is reasonably limited based on the current battery voltage to increase the repeated service life of the battery. In this way, the charging control module 13 can charge with different currents in different phases, and the first current range is smaller than the second current range. In this way, while limiting the charging current, the charging efficiency can also be correspondingly accelerated. The charging control module 13 can be implemented by a control chip or related circuits including a comparison circuit.

[0056] The charging protection circuit 10 includes: a battery voltage sampling module 11 connected to the battery 20, a reference voltage module 12, a charging control module 13, and a switch module 14. The switch module 14 is used to connect the charging power source 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 source VCC1, the switch module 14, under the control of the charging control module 13, connects the charging circuit between the charging power source VCC1 and the battery 20. The charging control module 13 is configured to control the on / off switching of the switch module 14 to maintain charging of the battery 20 in the first charging stage when the battery voltage sampled 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. Furthermore, when the battery voltage is greater than the first reference voltage, the charging control module 13 switches the battery 20 from the first charging stage to the second charging stage and controls the on / off switching of the switch module 14 to maintain charging of the battery 20 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. This circuit charges the battery 20 with an adaptive current at different charging stages, thereby avoiding overshoot that occurs during constant voltage charging. Furthermore, by configuring the reference voltage module 12 to output a first reference voltage, 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 switch module 14 to conduct, maintaining the battery 20 in the first charging stage with a lower charging current. Charging at a lower current during this stage can reduce polarization of the electrode material within the battery 20, preventing damage to the electrode material structure caused by high current charging, thereby significantly extending the cycle life of the battery 20. When the battery voltage collected by the battery voltage sampling module 11 is greater than the first reference voltage, the charging power supply is limited to maintaining a charging current greater than that of the first stage during the second charging stage. This can reduce the charging time of the battery 20 in the second charging stage, while also limiting the current range during the charging process to protect the rechargeable 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 the safety of the battery 20.

[0057] The charging control module 13 is an important part for achieving safe charging. In one embodiment, Figure 2As shown, the charging control module 13 includes a charging comparison unit 131, a charging switching unit 132 and a charging maintenance 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 maintenance unit 133 is used to connect the second terminal of the charging switching unit 132 to the switch module 14;

[0058] The charging comparison unit 131 is configured to output a first comparison signal to the charging switching unit 132 when the battery voltage is lower than the first reference voltage; and output a second comparison signal to the charging switching unit 132 when the battery voltage is higher than the first reference voltage;

[0059] The charging switching unit 132 is configured to output a first-stage charging signal to the charging maintaining unit 133 based on the first comparison signal; and output a second-stage charging signal to the charging maintaining unit 133 based on the second comparison signal;

[0060] The charging maintenance unit 133 is configured to control the switch module 14 to conduct the charging circuit between the charging power source VCC1 and the battery 20 when the charging power source VCC1 is connected. The charging maintenance unit 133 also controls the switch module 14 to be turned on and off based on the first-stage charging signal to maintain the first-stage charging process of the battery 20. The charging maintenance unit 133 is configured to control the switch module 14 to be turned on and off based on the second-stage charging signal to maintain the second-stage charging process of the battery 20.

[0061] In the embodiment of the present application, the charging control module 13 can be divided into three parts from a functional perspective, namely 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.

[0062] The charging comparison unit 131 has inputs including 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 charging comparison unit 131 compares the battery voltage with the first reference voltage and outputs different comparison signals to the charging switching unit 132 based on the comparison result. The charging comparison unit 131 can be implemented by a circuit composed of an operational amplifier and other electronic components, or by a control chip.

[0063] In one embodiment, Figure 3 As shown, the charging comparison unit 131 includes a resistor 1 R1, a resistor 2 R2 and a first operational amplifier U1;

[0064] The non-inverting input terminal of the first operational amplifier U1 is connected to the battery voltage sampling module 11, and the inverting input terminal of the first operational amplifier U1 is connected to the first terminal of the reference voltage module 12;

[0065] A first end of the resistor R1 is connected to the power supply VCC2 and a first end of the charging switching unit 132, respectively. A second end of the resistor R1 is connected to a first end of the resistor R2 and a second end of the charging switching unit 132, respectively. A second end of the resistor R2 is connected to the output end of the first operational amplifier U1.

[0066] The charging switching unit 132 has a first terminal connected to the output terminal of the charging comparison unit 131, configured to receive corresponding comparison signals at different charging stages of the battery 20. The charging comparison unit 131 may be a logic circuit composed of multiple AND gates, OR gates, and inverters. Alternatively, it may be implemented using an analog switching circuit.

[0067] In one embodiment, the charging switching unit 132 includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a first switch Q1, and a second operational amplifier U2.

[0068] A first end of resistor R3 and a first end of resistor R4 are both connected to the power supply VCC2. A second end of resistor R3 is connected to a first end of the first switch Q1. A second end of the first switch Q1 is connected to the output of the charge comparison unit 131. A third end of the first switch Q1, a second end of resistor R4, and a first end of resistor R5 are all connected to the inverting input of the second operational amplifier U2. Resistor R6 is used to connect the non-inverting input and output of the second operational amplifier U2. A second end of resistor R5 is grounded.

[0069] In the embodiment of the present application, after the first operational amplifier U1 compares the input battery voltage with the first reference voltage, the battery 20 can be determined to be in 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 selectively 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 terminal of the second operational amplifier U2, thereby controlling the battery 20 to switch from the first charging stage to the second charging stage.

[0070] 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 point, it can be determined that the battery 20 is in the first charging stage, i.e., the slow charging state. At this point, the first switch Q1 is off, and the voltage at the inverting input of the second operational amplifier U2 is determined by the power supply VCC2, the resistor R4, and the resistor R5. The corresponding formula can be expressed as:

[0071] The voltage at the inverting input terminal of the second operational amplifier U2 = VCC2 × (R5 / (R4+R5)).

[0072] At this time, the charging current of the 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.

[0073] 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, that is, the fast charging state. At this time, the first switch Q1 is in the on state, and the voltage at the inverting input of the second operational amplifier U2 is determined by the power supply VCC2, resistor three R3, resistor four R4 and resistor five R5. The corresponding formula can be expressed as:

[0074] The voltage at the inverting input terminal of the second operational amplifier U2 = VCC2×(R5 / (R4||R3+R5)), where R4||R3 represents the total resistance value of the resistor four R4 and the resistor three R3 connected in parallel.

[0075] 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.

[0076] At this time, the charging current of the 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.

[0077] The charge maintaining unit 133 includes a current limiting subunit 1331 and a switch control subunit 1332. The first end of the current limiting subunit 1331 is connected to the charge switching unit 132. The second end of the current limiting subunit 1331 and the battery voltage sampling module 11 are both connected to the first input end of the switch control subunit 1332. The second input end of the switch control subunit 1332 is connected to the second end of the reference voltage module 12. The output end of the switch control subunit 1332 is connected to the switch module 14.

[0078] The current limiting subunit 1331 is configured to increase 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;

[0079] The switch control subunit 1332 is configured to control the switch module 14 to be turned off when the input voltage is greater than the second reference voltage outputted by the second terminal of the reference voltage module 12 , so as to cut off the connection between the charging power source VCC1 and the battery 20 .

[0080] 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;

[0081] A first end of the first diode D1 is connected to the charging switching unit 132, a second end of the first diode D1 is connected to a first end of a resistor R7, a second end of the resistor R7 is connected to an inverting input of the third operational amplifier U3, and an inverting input of the third operational amplifier U3 is connected to the battery voltage sampling module 11 via a resistor R9. A non-inverting input of the third operational amplifier U3 is connected to a second end of the reference voltage module 12 via a resistor R10. An output of the third operational amplifier U3 is connected to a first end of a resistor R8, and a second end of the resistor R8 is connected to the switch module 14.

[0082] In the embodiment of the present application, whether the battery 20 is in the first or 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 the resistor R7 pull up the battery voltage at the inverting input of the third operational amplifier U3. Once the battery voltage exceeds 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. At this point, the charging current of the battery 20 gradually decreases to zero, preventing excessive current from flowing through the battery 20 during charging and improving the safety of the charging process.

[0083] The charging control module 13 includes a charging comparison unit 131, a charging switching unit 132 and a charging maintenance 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 maintenance unit 133 is used to connect the second terminal of the charging switching unit 132 to the switch module 14; 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 output a second comparison signal to the charging switching unit 133 when the battery voltage is greater than the first reference voltage. Element 132; charging switching unit 132 is configured to output a first-stage charging signal to charging maintenance unit 133 based on a first comparison signal; and to output a second-stage charging signal to charging maintenance unit 133 based on a second comparison signal; charging maintenance unit 133 is configured to control switch module 14 to connect the charging circuit between charging power source VCC1 and battery 20 when charging power source VCC1 is connected; further, based on the first-stage charging signal, control switch module 14 to turn on and off to maintain the first-stage charging process of battery 20; and based on the second-stage charging signal, control switch module 14 to turn on and off to maintain the second-stage charging process of battery 20. This circuit, through the coordinated operation of charging comparison unit 131, charging switching unit 132, and charging maintenance unit 133, implements slow charging with a low current in the first charging stage and fast charging with a high current in the second charging stage. This ensures that battery 20 remains within a safe current range throughout the charging process, preventing damage to the battery caused by excessive current, and enhancing the safety of battery 20 during charging.

[0084] Next, the specific contents of the battery voltage sampling module 11 are introduced through an embodiment. Figure 3 As shown, the battery voltage sampling module 11 includes a resistor 11 R11, a resistor 12 R12 and a resistor 13 R13, and the resistance of the resistor 13 R13 is determined based on the threshold voltage at the start of the second charging stage;

[0085] The first end of the resistor R11 is connected to the battery 20, the resistor R12 is used to connect the second end of the resistor R11 and the first end of the resistor R13, the second end of the resistor R13 is grounded, and the common end of the resistor R12 and the resistor R13 is connected to the charging control module 13.

[0086] In the embodiment of the present application, the battery voltage sampling module 11 includes three resistors. Among the three resistors, resistor 11 R11, resistor 12 R12, and resistor 13 R13 are voltage divider resistors, which mainly divide the collected battery voltage to prevent the battery voltage from being too high and causing damage to subsequent electronic components. The battery voltage collected by the battery voltage sampling module 11 can be expressed as:

[0087] Sampled battery voltage = (Vbat / (R7+R8+R9))×R9

[0088] Wherein, Vbat represents the voltage at the output end of the battery, Figure 3 Vbat+ represents the positive output terminal of the battery, and Vbat- represents the negative output terminal of the battery.

[0089] Different types of batteries 20 (e.g., nickel-metal hydride batteries, lithium-ion batteries, polymer batteries, etc.) have different charging characteristics and different threshold voltages for initiating the second charging phase. Because the resistance of resistor R13 can be flexibly adjusted based on the threshold voltage of different batteries, the battery voltage sampling module 11 is widely adaptable to various types of batteries.

[0090] The battery voltage sampling module 11 includes a resistor 11 R11, a resistor 12 R12, and a resistor 13 R13. The resistance of the resistor 13 R13 is determined based on the threshold voltage at the start of the second charging stage. The first end of the resistor 11 R11 is connected to the battery 20, and the resistor 12 R12 is used to connect the second end of the resistor 11 R11 and the first end of the resistor 13 R13. The second end of the resistor 13 R13 is grounded, and the common end of the resistor 12 R12 and the resistor 13 R13 is connected to the charging control module 13. The resistance of the resistor 13 R13 is determined based on the threshold voltage at the start of the second charging stage. This allows the battery voltage sampling module 11 to meet the sampling requirements of different types of batteries 20 and is suitable for voltage sampling of different types of batteries 20.

[0091] The above embodiments are all introductions to the charging control module 13. On this basis, in order to protect the charging process of the battery 20 even if the battery 20 is reversely connected, in one embodiment, Figure 3 As shown, the charging protection circuit 10 further includes a reverse connection protection module 15, and the reverse connection protection module 15 includes a second diode D2;

[0092] A first end of the second diode D2 is connected to a common end of the resistor eleven R11 and the resistor twelve R12, and a second end of the second diode D2 is grounded.

[0093] In an embodiment of the present application, when the positive and negative poles of the battery 20 are reversed and the battery 20 is charged by the charging power supply VCC1, the charging protection circuit 10 can limit the charging current through the reverse connection protection module 15 to ensure that the battery 20 will not be burned when the battery 20 is reversely connected. Specifically, when the 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 end to the common end of the resistor 11 R11 and the resistor 12 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 end of the reference voltage module 12. The first operational amplifier U1 outputs a low level, the first switch tube Q1 is not turned on, and the charging power supply VCC1 can continue to charge the 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, thereby cutting 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 achieving reverse connection protection for the battery 20.

[0094] The charging protection circuit 10 also includes a reverse connection protection module 15, which includes a second diode D2. The first end of the second diode D2 is connected to the common terminal of the resistor R10 and the resistor R11, and the second end of the second diode D2 is grounded. By incorporating the reverse connection protection module 15, the risk of component damage caused by reverse current is effectively avoided, ensuring that the battery 20 will not burn out in the event of reverse connection, thereby extending the service life of the battery 20.

[0095] Next, the specific contents of the switch module 14 are introduced through an embodiment. Figure 3 As shown, the switch module 14 includes a resistor 14 R14, a resistor 15 R15, a resistor 16 R16, a second switch tube Q2 and a third switch tube Q3;

[0096] A first end of the second switch tube Q2 is connected to a first end of a resistor 14 R14 and the charging control module 13. A second end of the second switch tube Q2 is connected to a first end of a resistor 15 R15. A second end of the resistor 15 R15 is respectively connected to a first end of a resistor 16 R16 and a first end of a third switch tube Q3. A second end of the third switch tube Q3 and a second end of the resistor 16 R16 are both connected to a charging power source VCC1. A third end of the third switch tube Q3 is connected to a battery 20. A third end of the second switch tube Q2 and a second end of the resistor 14 R14 are both grounded.

[0097] When charging power source VCC1 is connected to charging protection circuit 10, third switch Q3 is off, the battery voltage input to the inverting input of third operational amplifier U3 is 0V, the second reference voltage input to the non-inverting input is greater than the battery voltage, and the output of third operational amplifier U3 outputs a high-level signal. At this point, second switch Q2 is closed, third switch Q3 is on, and charging power source VCC1 can charge battery 20. During normal charging of battery 20, the battery voltage is less than the second reference voltage, and third operational amplifier U3 continuously outputs a high-level signal, turning on both second and third switches Q2 and Q3. During abnormal charging of battery 20 (excessive charging current), the battery voltage is greater than the second reference voltage, and third operational amplifier U3 outputs a low-level signal, turning off both second and third switches Q2 and Q3, gradually decreasing the charging current of battery 20 to zero. When the charging current of the battery 20 is 0 and the battery voltage is lower than the second reference voltage, the second switch Q2 and the third switch Q3 can continue to be turned on. This process is repeated to enable the battery 20 to be charged at different charging currents in different charging stages.

[0098] The switch module 14 includes a resistor 14, a resistor 15, a resistor 16, a second switch Q2, and a third switch Q3. The first end of the second switch Q2 is connected to the first end of the resistor 14 and the charging control module 13. The second end of the second switch Q2 is connected to the first end of the resistor 15. The second end of the resistor 15 is connected to the first end of the resistor 16 and the first end of the third switch Q3. The second end of the third switch Q3 and the second end of the resistor 16 are both connected to the charging power source VCC1. The third end of the third switch Q3 is connected to the battery 20. The third end of the second switch Q2 and the second end of the resistor 14 are both grounded. By providing two switches, this circuit can be turned on during charging, ensuring that the charging power source VCC1 can charge the battery 20. Furthermore, the switch module 14, through its connection to the current limiting subunit 1331, prevents damage to the battery 20 caused by excessive charging current through the switching action of the two switches, thereby ensuring the safety of the charging process.

[0099] For the reference voltage module 12, Figure 3 As shown, the reference voltage module 12 includes a resistor 17 R17, a resistor 18 R18 and a resistor 19 R19. The resistor 17 R17 is a sliding rheostat, and its resistance value can be adjusted based on different battery 20 requirements;

[0100] A first end of resistor R17 is connected to the power supply VCC2, a second end of resistor R17 is respectively connected to a first end of resistor R18 and an inverting input end of the first operational amplifier U1, a second end of resistor R18 is connected to a first end of resistor R19, and a second end of resistor R19 is grounded.

[0101] The reference voltage module 12 inputs a first reference voltage to the inverting input of the first operational amplifier U1 via the common terminal of resistors R17 and R18. Resistor R10 is connected to the third terminal of resistor R17. The reference voltage module 12 inputs a second reference voltage to the non-inverting input of the third operational amplifier U3 via resistors R17 and R10. The reference voltage module 12 can also input a third reference voltage to the non-inverting input of the fourth operational amplifier U4 via the common terminal of resistors R18 and R19.

[0102] It should be noted that the power supply VCC2 can be provided directly by a power supply, or can be obtained by voltage conversion through the charging power supply VCC1. Figure 3 For the AC power supply AC, a transformer T can be connected between AC+ and AC-. Transformer T transforms the voltage of the AC power supply, dividing it into two branches. In one branch, the output of transformer T is connected to the switch module 14 in the charging protection circuit 10 via a third diode D3, a fourth diode D4, and a first capacitor C1. The third diode D3 and the fourth diode D4 form a rectifier circuit, converting the AC power provided by the AC power supply AC into DC power. The first capacitor C1 is used for filtering and is connected to the second end of resistor R16 and the second end of the third switch transistor in the figure. 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 (refer to the circuit structure of different modules). For example, the voltage required by power supply VCC2 can be 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; and port c is grounded. Port a is the input voltage port (LINEVOLTAGE), port b is the voltage regulator (Voltage Regulator, VRGE), and port c is the ground terminal (COMMON).

[0103] In one embodiment, Figure 2As shown, the charging protection circuit 10 further includes a charging display module 16, which includes a current acquisition unit 161, a current comparison unit 162, and a light-emitting diode (LED). The input end of the current acquisition unit 161 is connected to the battery 20, the output end of the current acquisition unit 161 and the third end of the reference voltage module 12 are both connected to the input end of the current comparison unit 162, and the output end of the current comparison unit 162 is connected to the light-emitting diode (LED);

[0104] When the voltage corresponding to the current collected by the current collection 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 light-emitting diode LED to be in a light-emitting state;

[0105] When the voltage corresponding to the current collected by the current collection 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-luminous state.

[0106] In the embodiment of the present application, 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 20 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 electrode 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 end of resistors R18 and R19. The output 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 the light-emitting diode LED. The second end of the light-emitting diode LED is connected to the power supply VCC2.

[0107] If the input voltage of the non-inverting input terminal of the fourth operational amplifier U4 is greater than the input voltage of the inverting input terminal, the fourth operational amplifier U4 outputs a high-level signal, and the third reference voltage generated by the third terminal of the reference voltage module 12 is greater than the voltage corresponding to the current collected by the current collection unit 161. At this time, the battery 20 is fully charged and the light-emitting diode LED is in a non-luminous state.

[0108] 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, and the third reference voltage generated by the third terminal of the reference voltage module 12 is less than the voltage corresponding to the current collected by the current collection unit 161. At this time, when the battery 20 is in a normal charging process (including the battery 20 being in the first charging stage and the second charging stage), the light-emitting diode LED is in a light-emitting state.

[0109] The above-mentioned charging protection circuit 10 also includes a charging display module 16, which includes a current acquisition unit 161, a current comparison unit 162 and a light-emitting diode LED. The input end of the current acquisition unit 161 is connected to the battery 20, and the output end of the current acquisition unit 161 and the third end of the reference voltage module 12 are both connected to the input end of the current comparison unit 162, and the output end of the current comparison unit 162 is connected to the light-emitting diode LED; when the voltage corresponding to the current collected by the current acquisition unit 161 is greater than the third reference voltage generated by the third end 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 a light-emitting state; when the voltage corresponding to the current collected 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 light-emitting diode LED to be in a non-light-emitting state. By setting up a charging display module 16, the current collection unit 161 in the charging display module 16 is used to collect the current in the battery 20, and the voltage corresponding to the collected current is compared with the third reference voltage. Based on the comparison result, it is possible to accurately determine whether the battery 20 is full, and then use the on and off status of the light-emitting diode LED in the charging display module 16 to show the user whether the battery 20 is full, so that the user can understand the charging status of the battery 20 more intuitively.

[0110] Next, the working process of the charging protection circuit 10 is described in detail through a specific embodiment.

[0111] When AC power is connected, the third switch Q3 is off, the battery voltage input to the inverting input of the third operational amplifier U3 is 0V, and the output of the third operational amplifier U3 outputs a high level. This high-level signal turns on both the second and third switches Q2 and Q3. At this point, the AC power is rectified by transformer T to form a charging power source VCC1, which charges 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, causing the light-emitting diode LED to illuminate.

[0112] When the 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 and third switches Q2 and Q3 are in the on 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, causing the first operational amplifier U1 to output a low-level signal and disable the first switch Q1. At this point, the voltage at the inverting input of the second operational amplifier U2 is VCC2 × (R5 / (R4+R5)). During the current limiting process in the first charging stage, when the charging current of the battery 20 exceeds the maximum current of 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, resulting in a high-level signal output. This high-level signal pulls up the battery voltage at the inverting input of the third operational amplifier U3. Consequently, the output of the third operational amplifier U3 outputs a low-level signal. The second and third switches Q2 and Q3 are both turned off. After the charging current of the battery 20 gradually decreases to zero, the battery voltage input to the inverting input of the third operational amplifier U3 becomes lower than the second reference voltage input to the non-inverting input, and the second and third switches Q2 and Q3 are turned on. This cycle repeats, thereby limiting the charging current of the battery 20 during the first charging stage.

[0113] When the battery voltage slowly rises to a certain voltage threshold (determined by the resistance of resistor R13), the battery voltage input to the inverting input of the third operational amplifier U3 is lower 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 lower than the battery voltage input to the non-inverting input, causing the first operational amplifier U1 to output a high-level signal, turning on the first switch Q1. At this point, the voltage at the inverting input of the second operational amplifier U2 is VCC2 × (R5 / (R4||R3+R5)). During the current limiting process in the second charging stage, when the charging current of the battery 20 exceeds the maximum current of the second charging stage, the voltage at the non-inverting input of the second operational amplifier U2 is higher than the voltage at the inverting input, resulting in a high-level signal output. This high-level signal pulls up the battery voltage at the inverting input of the third operational amplifier U3, causing the output of the third operational amplifier U3 to output a low-level signal. The second and third switches Q2 and Q3 are both turned off. After the charging current of the battery 20 gradually decreases to zero, the battery voltage input to the inverting input of the third operational amplifier U3 becomes lower than the second reference voltage input to the non-inverting input, and the second and third switches Q2 and Q3 are turned on. This cycle repeats, thereby limiting the charging current of the battery 20 during the second charging phase.

[0114] When the battery 20 completes the charging process of the first charging stage and the second charging stage and is fully charged, the light emitting diode LED switches from a light emitting state to a non-light emitting state.

[0115] It should be noted that, among the reference voltages output by the reference voltage module 12 , the third reference voltage is greater than the second reference voltage, and the second reference voltage is greater than the first reference voltage.

[0116] In addition, continue to refer 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 may also be provided between the resistor R11 in the battery voltage sampling module 11, the third terminal of the third switch Q3 in the switch module 14, and the positive output terminal of the battery.

[0117] When a short circuit occurs in the charging protection circuit 10 or the battery connected to it, the short-circuit current increases dramatically. The fuse element of fuse FU melts rapidly at the high temperature generated by the short-circuit current, severing the connection between the charging protection circuit 10 and the battery 20. This prevents the short-circuit current from causing serious damage to the battery and circuit components in the charging protection circuit 10, and avoids safety accidents such as overheating, fire, or even explosion caused by the short circuit.

[0118] In another embodiment, a charger is provided. The charger includes the charging protection circuit 10 involved in the above embodiment.

[0119] Alternatively, the charger can be fixed in a set position and connected to the charging power source VCC1. For this purpose, reference can be made to a charging station for a new energy vehicle. Alternatively, the charger can be portable, such as an electric vehicle charger, a mobile phone charger, etc.

[0120] The above content is a further detailed description of the embodiments of the present application in conjunction with specific / preferred embodiments, and it cannot be determined that the specific implementation of the embodiments of the present application is limited to these descriptions. For ordinary technicians in the technical field of the embodiments of the present application, without departing from the concept of the embodiments of the present application, they can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be considered to belong to the scope of protection of the embodiments of the present application. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in an appropriate manner. The various technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the various 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.

[0121] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, 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 application.

[0122] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A charging protection circuit, characterized in that: The charging protection circuit includes: a battery voltage sampling module connected to the battery, a reference voltage module, a charging control module, and a switch module for connecting a charging power source and the battery; The charging control module includes a charging comparison unit, a charging switching unit, and a charging maintenance unit. The first input terminal, the second input terminal, and the output terminal of the charging comparison unit are respectively connected to the battery voltage sampling module, the first terminal of the reference voltage module, and the first terminal of the charging switching unit. The charging maintenance unit is used to connect the second terminal of the charging switching unit to the switch module. The charging comparison unit is configured to output a first comparison signal to the charging switching unit when the battery voltage is lower than a first reference voltage; and output a second comparison signal to the charging switching unit when the battery voltage is higher than the first reference voltage; The charging switching unit is configured to output a first-stage charging signal to the charging maintaining unit based on the first comparison signal; and output a second-stage charging signal to the charging maintaining unit based on the second comparison signal; The charging maintenance unit is configured to control the switch module to conduct a charging circuit between the charging power source and the battery when the charging power source is connected; and is further configured to control the switching module to be turned 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 be turned on and off based on the second-stage charging signal to maintain the second-stage charging process of the battery; The charge maintenance unit includes a current limiting subunit and a switch control subunit, wherein a first end of the current limiting subunit is connected to the charge switching unit, a second end of the current limiting subunit and the battery voltage sampling module are both connected to a first input end of the switch control subunit, a second input end of the switch control subunit is connected to a second end of the reference voltage module, and an output end of the switch control subunit is connected to the switch module; The current limiting subunit is configured to increase 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 configured to control the switch module to turn off when the input voltage is greater than the second reference voltage output by the second end of the reference voltage module, so as to cut off the connection between the charging power supply and the battery.

2. The circuit according to claim 1, wherein: The charging comparison unit includes a resistor 1, a resistor 2 and a first operational amplifier; The non-inverting input terminal of the first operational amplifier is connected to the battery voltage sampling module, and the inverting input terminal of the first operational amplifier is connected to the first terminal of the reference voltage module; The first end of the resistor 1 is connected to the power supply and the first end of the charging switching unit respectively, the second end of the resistor 1 is connected to the first end of the resistor 2 and the second end of the charging switching unit respectively, and the second end of the resistor 2 is connected to the output end of the first operational amplifier.

3. The circuit according to claim 1, wherein: The charging switching unit includes a resistor three, a resistor four, a resistor five, a resistor six, a first switch tube and a second operational amplifier; The first end of the resistor three and the first end of the resistor four are both connected to the power supply, the second end of the resistor three is connected to the collector of the first switching tube, the base of the first switching tube is connected to the output end of the charging comparison unit, the emitter of the first switching tube, the second end of the resistor four, and the first end of the resistor five are all connected to the inverting input end of the second operational amplifier, the resistor six is ​​used to connect the non-inverting input end and the output end of the second operational amplifier, and the second end of the resistor five is grounded.

4. The circuit according to claim 1, wherein: The current limiting subunit includes a first diode and a resistor seven, and the switch control subunit includes a resistor eight, a resistor nine, a resistor ten and a third operational amplifier; The anode of the first diode is connected to the charging switching unit, the cathode 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 end of the third operational amplifier, and the inverting input end of the third operational amplifier is connected to the battery voltage sampling module through the resistor nine, the non-inverting input end of the third operational amplifier is connected to the second end of the reference voltage module through the resistor ten, the output end 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 switch module.

5. The circuit according to any one of claims 1 to 4, characterized in that: The battery voltage sampling module includes a resistor 11, a resistor 12, and a resistor 13, wherein the resistance value of the resistor 13 is determined based on the threshold voltage at the start of the second charging stage; The first end of the resistor 11 is connected to the battery, the resistor 12 is used to connect the second end of the resistor 11 and the first end of the resistor 13, the second end of the resistor 13 is grounded, and the common end of the resistor 12 and the resistor 13 is connected to the charging control module.

6. The circuit according to claim 5, characterized in that The charging protection circuit further includes a reverse connection protection module, and the reverse connection protection module includes a second diode; A first end of the second diode is connected to a common end of the resistor 11 and the resistor 12, and a second end of the second diode is grounded.

7. The circuit according to any one of claims 1 to 4, characterized in that: The switch module includes a resistor 14, a resistor 15, a resistor 16, a second switch tube and a third switch tube; The base of the second switching tube is connected to the first end of the resistor 14 and the charging control module, the collector of the second switching tube is connected to the first end of the resistor 15, the second end of the resistor 15 is respectively connected to the first end of the resistor 16 and the gate of the third switching tube, the source of the third switching tube and the second end of the resistor 16 are both connected to the charging power supply, the drain of the third switching tube is connected to the battery, and the emitter of the second switching tube and the second end of the resistor 14 are both grounded.

8. The circuit according to any one of claims 1 to 4, characterized in that: 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 end of the current acquisition unit is connected to the battery, the output end of the current acquisition unit and the third end of the reference voltage module are both connected to the input end of the current comparison unit, and the output end of the current comparison unit is connected to the light-emitting diode. When the voltage corresponding to the current collected by the current collection unit is greater than the third reference voltage generated by 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 a light-emitting state; When the voltage corresponding to the current collected by the current collection unit is less than the third reference voltage, the battery is in a fully charged state, 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-luminous state.

9. The circuit according to any one of claims 1 to 4, characterized in that: The reference voltage module includes a resistor 17, a resistor 18 and a resistor 19, wherein the resistor 17 is a sliding rheostat; The first end of the resistor 17 is connected to the power supply, the second end of the resistor 17 is respectively connected to the first end of the resistor 18 and the inverting input end of the first operational amplifier, the second end of the resistor 18 is connected to the first end of the resistor 19, and the second end of the resistor 19 is grounded.

10. A charger, characterized in that: The charger includes the charging protection circuit according to any one of claims 1 to 9.

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