Charging protection circuit and charger

Abstract

The utility model relates to a charging protection circuit and a charger. The charging protection circuit comprises a charging switch control module and a square wave generation module, a first end of the charging switch control module is connected with an input power supply, a second end of the charging switch control module is connected with an input end of the square wave generation module, and an output end of the square wave generation module is connected with a third end of the charging switch control module. The fourth end of the charging switch control module is connected with the battery; the square wave generation module comprises a thermistor; when the charging switch control module controls the charging path to be conducted, the resistance value of the thermistor is increased along with temperature rise so as to adjust the period of a square wave signal input to the third end of the charging switch control module by the square wave generation module, and the charging switch control module is used for adjusting the switching frequency of the charging path according to the period of the square wave signal. The charging protection circuit can reduce the temperature of the battery.

Description

Technical Field

[0001] This application relates to the field of battery charging technology, and in particular to a charging protection circuit and a charger. Background Technology

[0002] In today's electronic devices and energy storage technology fields, batteries, as key energy storage components, have always been a focus of attention regarding the safety and stability of their charging process and their impact on battery life.

[0003] In related technologies, a constant DC power source is commonly used to charge batteries. This method can easily lead to high battery temperatures, which may affect the safety of battery charging.

[0004] Therefore, there is an urgent need for a charging protection circuit that can reduce battery temperature. Utility Model Content

[0005] Therefore, it is necessary to provide a charging protection circuit and charger that can reduce battery temperature to address the aforementioned technical problems.

[0006] In a first aspect, this application provides a charging protection circuit, which includes a charging switch control module and a square wave generator module. The first terminal of the charging switch control module is connected to the input power supply, the second terminal of the charging switch control module is connected to the input terminal of the square wave generator module, the output terminal of the square wave generator module is connected to the third terminal of the charging switch control module, and the fourth terminal of the charging switch control module is connected to the battery. The square wave generator module includes a thermistor.

[0007] When the charging switch control module controls the charging path to be turned on, the resistance of the thermistor increases with the temperature to adjust the period of the square wave signal input from the square wave generator to the third terminal of the charging switch control module. The charging switch control module is used to adjust the switching frequency of the charging path according to the period of the square wave signal.

[0008] In one embodiment, the square wave generating module further includes an operational amplifier unit and a capacitor. The first input terminal of the operational amplifier unit is connected to the second terminal of the charging switch control module, the first terminal of the capacitor is connected to the second input terminal of the operational amplifier unit, and a thermistor is disposed between the second input terminal and the output terminal of the operational amplifier unit. The second terminal of the capacitor is grounded.

[0009] In one embodiment, the operational amplifier unit includes a resistor one, a resistor two, and a first operational amplifier. The resistor one is disposed between the non-inverting input terminal of the first operational amplifier and the second terminal of the charging switch control module, and the resistor two is disposed between the non-inverting input terminal of the first operational amplifier and the output terminal of the first operational amplifier.

[0010] In one embodiment, the charging switch control module includes an input voltage sampling unit, a battery voltage sampling unit, a charging comparison unit, and a switching unit;

[0011] The input terminal of the input voltage sampling unit is connected to the input power supply and is used to sample the input voltage of the input power supply. The output terminal of the input voltage sampling unit is connected to the first terminal of the switching unit and the first input terminal of the charging comparison unit, respectively.

[0012] The input terminal of the battery voltage sampling unit is connected to the second terminal of the battery and the switch unit respectively, and the output terminal of the battery voltage sampling unit is connected to the second input terminal of the charging comparison unit, and is used to sample the charging mapping voltage of the battery.

[0013] The output of the charging comparator is connected to the input of the square wave generator module and is used to compare the input voltage and the charging mapped voltage, and output a level signal to the square wave generator module based on the comparison result.

[0014] The third terminal of the switching unit is connected to the output terminal of the square wave generator module. The square wave signal output by the square wave generator module is transmitted to the third terminal of the switching unit. The switching unit is used to control the switching frequency connected to the battery according to the period of the square wave signal.

[0015] In one embodiment, the input voltage sampling unit includes resistor three, resistor four, resistor five, resistor six, a Zener diode, and a first switching transistor;

[0016] The first end of resistor three, the first end of resistor five, and the first end of the first switching transistor are all connected to the input power supply. The second end of resistor three is connected to the first end of the Zener diode and the first end of resistor four, respectively.

[0017] The second terminal of the first switching transistor is connected to the first input terminal of the charging comparator unit and the first terminal of the switching unit, respectively. The third terminal of the first switching transistor is connected to the first terminal of resistor six. The second terminals of resistor six and resistor five are both connected to the second terminal of the Zener diode. The second terminal of resistor four and the third terminal of the Zener diode are grounded.

[0018] In one embodiment, the charging comparator unit includes resistor seven, resistor eight, and a second operational amplifier;

[0019] The first end of resistor 7 is connected to the output end of the input voltage sampling unit and the first end of the switching unit. The second end of resistor 7 and the first end of resistor 8 are both connected to the inverting input end of the second operational amplifier. The non-inverting input end of the second operational amplifier is connected to the output end of the battery voltage sampling unit. The output end of the second operational amplifier is connected to the input end of the square wave generating module.

[0020] In one embodiment, the switching unit includes resistor nine, resistor ten, diode, and second switching transistor;

[0021] The first end of resistor 9 and the first end of diode are both connected to the output end of input voltage sampling unit. The second end of resistor 9 is connected to the first end of second switch transistor. The second end of second switch transistor is connected to the input end of battery voltage sampling unit and battery, respectively. The third end of second switch transistor and the second end of diode are connected to the first end of resistor 10. The second end of resistor 10 is connected to the output end of square wave generator module.

[0022] In one embodiment, the battery voltage sampling unit includes resistor eleven and resistor twelve, wherein resistor twelve is a sliding rheostat;

[0023] The first end of resistor eleven is connected to the second end of the switching unit and the battery, the second end of resistor eleven is connected to the first end of resistor twelf, and the second end of resistor twelf is connected to the second input end of the charging comparator unit.

[0024] In one embodiment, the charging protection circuit further includes a charging display module for indicating the battery charging status based on the output result of the charging comparison unit; the charging display module is connected to the output terminal of the charging comparison unit and the input terminal of the square wave generator module, respectively.

[0025] The charging display module includes resistor thirteen, resistor fourteen, a first light-emitting diode, and a second light-emitting diode;

[0026] The first terminal of resistor 13 is connected to the output terminal of the battery voltage sampling unit and the first terminal of the switching unit, and the second terminal of resistor 13 is connected to the first terminal of the first light-emitting diode.

[0027] The second terminal of the first LED is connected to the first terminal of the resistor fourteen and the output terminal of the charging comparator unit, respectively. The second terminal of the resistor fourteen is connected to the first terminal of the second LED, and the second terminal of the second LED is grounded.

[0028] Secondly, this application also provides a charger that includes a charging protection circuit according to any one of the first aspects described above.

[0029] The aforementioned charging protection circuit and charger include a charging switch control module and a square wave generator module. The first terminal of the charging switch control module is connected to the input power supply, the second terminal is connected to the input terminal of the square wave generator module, the output terminal of the square wave generator module is connected to the third terminal of the charging switch control module, and the fourth terminal is connected to the battery. The square wave generator module includes a thermistor. When the charging switch control module controls the charging path to be turned on, the resistance of the thermistor increases with increasing temperature to adjust the period of the square wave signal input from the square wave generator module to the third terminal of the charging switch control module. The charging switch control module is used to adjust the switching frequency of the charging path according to the period of the square wave signal. In this charging protection circuit, when the charging switch control module turns on the charging path, the thermistor in the square wave generator module adjusts its resistance according to the temperature change of the battery during charging; that is, as the battery temperature increases, the resistance of the thermistor increases, thereby changing the period of the square wave signal output by the square wave generator module. The charging switch control module then adjusts the switching frequency of the charging path according to the square wave signal period. In other words, when the battery temperature is high, the square wave signal period gradually increases as the temperature rises, thereby causing the switching frequency of the charging path in the charging switch control module to gradually decrease during the charging process. This can avoid safety issues such as circuit failure or battery damage caused by overheating and improve the safety of the battery charging process. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a circuit diagram of the charging protection circuit in one embodiment;

[0032] Figure 2 This is a circuit diagram of a charging protection circuit in one embodiment.

[0033] Explanation of reference numerals in the attached figures:

[0034] 10: Charging protection circuit;

[0035] 11: Charging switch control module;

[0036] 111: Input voltage sampling unit;

[0037] 112: Battery voltage sampling unit;

[0038] 113: Charging comparator unit;

[0039] 114: Switching unit;

[0040] 12: Square wave generator module;

[0041] 121: Operational amplifier unit;

[0042] 13: Charging display module. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0044] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0045] In this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to electrical connections, direct connections, or indirect connections via an intermediate medium, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] Before providing a detailed introduction to the technical solution of this application, let me first briefly introduce the background technology of this application.

[0047] During battery charging, the battery temperature continuously rises over time. From a charging principle perspective, battery charging is a process of converting electrical energy into chemical energy. However, not all the input electrical energy is completely converted and stored as chemical energy. In fact, some electrical energy is lost as heat, which is known as energy loss during charging. Furthermore, the battery's material properties and the heat dissipation conditions during charging also contribute to the continuous temperature increase.

[0048] Increased battery temperature not only affects charging efficiency, performance, and lifespan, but may also adversely impact battery safety. Therefore, reducing battery temperature during charging has become an urgent problem to be solved.

[0049] To address the aforementioned problems, this application provides a charging protection circuit and charger. By utilizing the temperature-sensitive characteristics of a thermistor, the period of the square wave signal output by the square wave generator module is adjusted, thereby changing the switching frequency during the charging process. This reduces the battery temperature during charging, thus improving the safety of the battery charging process. Of course, the technical solutions provided in this application are not limited to solving only the above problems and also offer other technical effects, which can be found in the following embodiments. The technical solutions of this application will now be described in detail.

[0050] In one embodiment, such as Figure 1 As shown, a charging protection circuit 10 is provided. The charging protection circuit 10 includes a charging switch control module 11 and a square wave generator module 12. The first terminal of the charging switch control module 11 is connected to the input power supply Vin, the second terminal of the charging switch control module 11 is connected to the input terminal of the square wave generator module 12, the output terminal of the square wave generator module 12 is connected to the third terminal of the charging switch control module 11, and the fourth terminal of the charging switch control module 11 is connected to the battery 20. The square wave generator module 12 includes a thermistor RT.

[0051] During the process of controlling the charging path to open and close by the charging switch control module 11, the resistance of the thermistor RT changes with temperature to adjust the period of the square wave signal input from the square wave generator module 12 to the third terminal of the charging switch control module 11. The charging switch control module 11 adjusts the switching frequency of the charging path according to the period of the square wave signal. Specifically, when the battery temperature is high, the period of the square wave signal gradually increases as the temperature rises, thereby gradually reducing the switching frequency of the charging path during the charging process. This avoids safety issues such as circuit failure or battery damage caused by overheating, improving the safety of the battery charging process.

[0052] In this embodiment, the charging protection circuit 10 is disposed between the input power supply Vin and the battery 20. The input power supply Vin is used to charge the battery 20, and the charging protection circuit 10 is used to suppress the temperature rise of the battery 20 during the charging process, thereby protecting the charging safety of the battery 20.

[0053] The charging protection circuit 10 includes two modules: a charging switch control module 11 for controlling the charging switching process and a square wave generator module 12 for controlling the switching frequency. These two modules will be described in detail below.

[0054] First, the details of the charging switch control module 11 will be explained. The charging switch control module 11 can be turned on when the input power supply Vin can charge the battery 20, and turned off when the input power supply Vin cannot charge the battery 20. Simply put, it controls whether the battery 20 is charged or not. The charging switch control module 11 can be an intelligent switch controller with high-precision current and voltage detection capabilities and fast switching response speed, or a switch module composed of switching transistors, etc.

[0055] The following is a detailed description of the square wave generating module 12. The square wave generating module 12 includes a thermistor RT and other electronic components. The thermistor RT is mainly used to sense the temperature change of the battery 20 when the input power supply Vin is charging the battery 20. Its resistance increases with increasing temperature. By adjusting its own resistance, the period of the output square wave is adjusted, thereby changing the switching frequency of the charging process to reduce the temperature of the battery 20 during charging. In other words, the thermistor RT and other electronic components constitute an oscillation circuit, adjusting the oscillation frequency by changing its own resistance, thus generating square wave signals of different periods. The thermistor RT can be a positive temperature coefficient thermistor.

[0056] It is understandable that the square wave signal period can be adjusted not only when the battery 20 temperature is high, but also when the battery 20 temperature is low, to improve charging efficiency. For example, when the battery 20 temperature is low and the charging demand is high, the square wave signal period will be appropriately shortened, the switching frequency will be increased, and the charging current will be increased to speed up the charging process. Conversely, when the battery 20 temperature rises or is nearing full charge, the square wave signal period will be lengthened, the switching frequency will be reduced, and the charging current will be decreased to prevent overcharging, thus further improving charging efficiency.

[0057] In summary, the charging protection circuit 10 can control whether the input power Vin charges the battery 20 through the charging switch control module 11, and during the charging process, the square wave generator module 12 can change the charging frequency to reduce the temperature of the battery 20 during the charging process and ensure the safety of charging the battery 20.

[0058] The charging protection circuit 10 includes a charging switch control module 11 and a square wave generator module 12. The first terminal of the charging switch control module 11 is connected to the input power supply Vin, the second terminal of the charging switch control module 11 is connected to the input terminal of the square wave generator module 12, the output terminal of the square wave generator module 12 is connected to the third terminal of the charging switch control module 11, and the fourth terminal of the charging switch control module 11 is connected to the battery 20. The square wave generator module 12 includes a thermistor RT. When the charging switch control module 11 controls the charging path to be turned on, the resistance of the thermistor RT increases with the temperature to adjust the period of the square wave signal input from the square wave generator module 12 to the third terminal of the charging switch control module 11. The charging switch control module 11 is used to adjust the switching frequency of the charging path according to the period of the square wave signal. In this charging protection circuit 10, when the charging switch control module 11 turns on the charging path, the thermistor RT in the square wave generator module 12 adjusts its resistance value according to the temperature change of the battery 20 during the charging process. That is, as the temperature of the battery 20 increases, the resistance value of the thermistor RT increases, thereby changing the period of the square wave signal output by the square wave generator module 12. The charging switch control module 11 then adjusts the switching frequency of the charging path according to the period of the square wave signal. In other words, when the temperature of the battery 20 is high, as the temperature continues to rise, the period of the square wave signal gradually increases, thereby causing the switching frequency of the charging path of the charging switch control module 11 to gradually decrease during the charging process. This can avoid safety problems such as circuit failure or battery 20 damage caused by overheating, and improve the safety of the battery 20 charging process.

[0059] The aforementioned square wave generating module 12 can adopt a circuit design centered on an operational amplifier circuit. Therefore, in one embodiment, such as... Figure 2 As shown, the square wave generating module 12 also includes an operational amplifier unit 121 and a capacitor C. The first input terminal of the operational amplifier unit 121 is connected to the second terminal of the charging switch control module 11. The first terminal of the capacitor C is connected to the second input terminal of the operational amplifier unit 121. The thermistor RT is disposed between the second input terminal and the output terminal of the operational amplifier unit 121. The second terminal of the capacitor C is grounded.

[0060] In this embodiment of the application, in order to effectively protect the battery 20 at a high temperature during the charging process, a circuit including an operational amplifier unit 121, a thermistor RT and a capacitor C can be used. This circuit can dynamically adjust the square wave output signal according to the temperature change of the battery 20 during charging, thereby changing the working state of the charging switch control module 11 to ensure the safety and efficiency of the charging process.

[0061] The operational amplifier unit 121 includes two input terminals and one output terminal. The two input terminals are the charging mapping voltage input from the charging switch control module 11 and the battery 20 temperature sensing voltage, respectively. The battery 20 temperature sensing voltage is input through the thermistor RT and the capacitor C.

[0062] It is understandable that different batteries 20 have different temperature change characteristics and charging parameter requirements during the charging process. By adjusting the parameters of the thermistor RT and the amplification factor of the operational amplifier unit 121, the square wave generation module 12 can provide a suitable square wave signal for different types of batteries 20, thereby achieving compatible charging of multiple batteries 20.

[0063] The operational amplifier unit 121 outputs square wave signals of different periods by comparing the charging mapped voltage and the temperature sensing voltage of the battery 20. Since the operational amplifier unit 121 needs to accurately amplify and process the input signal, it needs to have characteristics such as high gain, low offset voltage, and low noise.

[0064] It should be noted that the period T of the square wave output by the square wave output unit can be expressed as:

[0065] T=RT*C

[0066] In this equation, RT represents a thermistor, and C represents a capacitor. As can be seen from the formula above, as the resistance of the thermistor RT and the capacitance of the capacitor C change, the period T of the square wave signal also changes. For example, the capacitor C can be a ceramic capacitor, a ceramic dielectric capacitor, a polyester capacitor, an electrolytic capacitor, or a tantalum capacitor, etc.

[0067] In one embodiment, the operational amplifier unit 121 may include an operational amplifier and other electronic components. Specifically, the operational amplifier unit 121 includes a resistor R1, a resistor R2, and a first operational amplifier U1. The resistor R1 is disposed between the non-inverting input terminal of the first operational amplifier U1 and the second terminal of the charging switch control module 11. The resistor R2 is disposed between the non-inverting input terminal of the first operational amplifier U1 and the output terminal of the first operational amplifier U1. The first terminal of the capacitor C and the first terminal of the thermistor RT are both connected to the inverting input terminal of the first operational amplifier U1.

[0068] The resistance values ​​of resistors R1 and R2 in operational amplifier unit 121 can be determined based on the required amplification factor. Before circuit design, the resistance values ​​of R1 and R2 can be calculated using the amplification factor of the operational amplifier. Both R1 and R2 can be high-precision resistors with low temperature coefficients, ensuring stable resistance values ​​under different temperature conditions and guaranteeing accurate transmission of the input signal. The first operational amplifier U1 can be selected with characteristics such as high gain, low offset voltage, and low noise to meet the high-precision signal amplification and processing requirements of the charging protection circuit 10.

[0069] The aforementioned square wave generating module 12 further includes an operational amplifier unit 121 and a capacitor C. The first input terminal of the operational amplifier unit 121 is connected to the second terminal of the charging switch control module 11, the first terminal of the capacitor C is connected to the second input terminal of the operational amplifier unit 121, and a thermistor RT is disposed between the second input terminal and the output terminal of the operational amplifier unit 121. The second terminal of the capacitor C is grounded. The operational amplifier unit 121 includes a resistor R1, a resistor R2, and a first operational amplifier U1. Resistor R1 is disposed between the non-inverting input terminal of the first operational amplifier U1 and the second terminal of the charging switch control module 11, and resistor R2 is disposed between the non-inverting input terminal and the output terminal of the first operational amplifier U1. By placing the thermistor RT between the second input terminal and the output terminal of the operational amplifier unit 121, the resistance value of the thermistor RT changes as the temperature of the battery 20 rises during the charging process. Based on the change in the resistance value of the thermistor RT affecting the output of the operational amplifier unit 121, the period of the square wave signal output by the square wave generation module 12 is changed, thereby changing the charging frequency and reducing the charging temperature of the battery 20.

[0070] The following is a detailed description of the charging switch control module 11 described above, using an example. See also... Figure 2 The charging switch control module 11 mentioned above includes an input voltage sampling unit 111, a battery voltage sampling unit 112, a charging comparison unit 113, and a switching unit 114.

[0071] The input terminal of the input voltage sampling unit 111 is connected to the input power supply Vin and is used to sample the input voltage of the input power supply Vin. The output terminal of the input voltage sampling unit 111 is connected to the first terminal of the switching unit 114 and the first input terminal of the charging comparison unit 113, respectively.

[0072] The input terminal of the battery voltage sampling unit 112 is connected to the second terminal of the battery 20 and the switching unit 114 respectively. The output terminal of the battery voltage sampling unit 112 is connected to the second input terminal of the charging comparison unit 113 and is used to sample the charging mapping voltage of the battery 20.

[0073] The output terminal of the charging comparison unit 113 is connected to the input terminal of the square wave generator module 12 and is used to compare the input voltage and the charging mapping voltage, and output a level signal to the square wave generator module 12 based on the comparison result.

[0074] The third terminal of the switching unit 114 is connected to the output terminal of the square wave generating module 12. The square wave signal output by the square wave generating module 12 is transmitted to the third terminal of the switching unit 114. The switching unit 114 is used to control the switching frequency connected to the battery 20 according to the period of the square wave signal.

[0075] In this embodiment, the input voltage sampling unit 111 is mainly used to collect the input voltage of the input power supply Vin, and the battery voltage sampling unit 112 is mainly used to collect the charging mapped voltage of the battery 20 during the charging process. Both the input voltage of the input power supply Vin and the voltage of the battery 20 are input to the charging comparison unit 113. The charging comparison unit 113 determines whether the battery 20 is fully charged by comparing the two voltages. Specifically, when the output level of the charging comparison unit 113 is low, it indicates that the input voltage of the input power supply Vin is greater than the charging mapped voltage of the battery 20. At this time, the battery 20 is not fully charged and is in the charging state. When the output level of the charging comparison unit 113 is high, it indicates that the input voltage of the input power supply Vin is less than or equal to the voltage of the battery 20. At this time, the battery 20 is fully charged.

[0076] If it is determined that battery 20 is not fully charged, the charging comparator unit 113 outputs a low-level signal, and the first operational amplifier U1 outputs a square wave signal, controlling the switch unit 114 to turn on, allowing the input power supply Vin to charge battery 20. If it is determined that battery 20 is fully charged, the charging comparator unit 113 outputs a high-level signal, and the first operational amplifier U1 cannot output a square wave signal. At this time, the switch unit 114 turns off, preventing the input power supply Vin from charging battery 20.

[0077] The specific contents of the input voltage sampling unit 111, the charging comparison unit 113, the switching unit 114, and the battery voltage sampling unit 112 will be introduced in turn.

[0078] For the input voltage sampling unit 111, the input voltage sampling unit 111 includes resistor three R3, resistor four R4, resistor five R5, resistor six R6, Zener diode D1 and first switching transistor Q1;

[0079] The first terminal of resistor 3R3, the first terminal of resistor 5R5, and the first terminal of the first switching transistor Q1 are all connected to the input power supply Vin. The second terminal of resistor 3R3 is connected to the first terminal of Zener diode D1 and the first terminal of resistor 4R4, respectively.

[0080] The second terminal of the first switching transistor Q1 is connected to the first input terminal of the charging comparator unit 113 and the first terminal of the switching unit 114, respectively. The third terminal of the first switching transistor Q1 is connected to the first terminal of the resistor R6. The second terminals of the resistor R6 and the resistor R5 are both connected to the second terminal of the Zener diode D1. The second terminal of the resistor R4 and the third terminal of the Zener diode D1 are grounded.

[0081] For the charging comparator unit 113, the charging comparator unit 113 includes resistor 7 R7, resistor 8 R8 and second operational amplifier U2;

[0082] The first end of resistor 7 R7 is connected to the output end of input voltage sampling unit 111 and the first end of switch unit 114. The second end of resistor 7 R7 and the first end of resistor 8 R8 are both connected to the inverting input end of the second operational amplifier U2. The non-inverting input end of the second operational amplifier U2 is connected to the output end of battery voltage sampling unit 112. The output end of the second operational amplifier U2 is connected to the input end of square wave generation module 12.

[0083] For the switching unit, the switching unit includes resistor R9, resistor R10, diode D2, and second switching transistor Q2;

[0084] The first end of resistor R9 and the first end of diode D2 are both connected to the output end of input voltage sampling unit 111. The second end of resistor R9 is connected to the first end of second switch Q2. The second end of second switch Q2 is connected to the input end of battery voltage sampling unit 112 and battery 20, respectively. The third end of second switch Q2 and the second end of diode D2 are connected to the first end of resistor R10. The second end of resistor R10 is connected to the output end of square wave generation module 12.

[0085] For the battery voltage sampling unit 112, the battery voltage sampling unit 112 includes resistor eleven R11 and resistor twelve R12, and resistor twelve R12 is a sliding rheostat;

[0086] The first end of resistor 11R11 is connected to the second end of switch unit 114 and battery 20 respectively. The second end of resistor 11R11 is connected to the first end of resistor 12R12. The second end of resistor 12R12 is connected to the input end of charging comparator unit 113.

[0087] In this embodiment, after the input power supply Vin, the charging protection circuit 10, and the battery 20 are connected, when the input voltage of the input power supply Vin is within the charging mapping voltage range, the voltage at the common terminal of resistors R3 and R4 is greater than the reference voltage of Zener diode D1 (for example, the reference voltage of Zener diode D1 can be 2.5V). Zener diode D1 starts working, the first switch Q1 is turned on, and the input power supply Vin can charge the battery 20. At this time, resistor R5 can provide operating current for Zener diode D1.

[0088] When the input voltage of the input power supply Vin is not within the charging mapping voltage range, the Zener diode D1 does not work, the first switch Q1 is turned off, and the input power supply Vin cannot charge the battery 20. Specifically, the input voltage of the input power supply Vin can be determined by setting the resistance values ​​of resistors R3 and R4.

[0089] Resistors R7 and R8 are used to sample the input voltage of the input power supply Vin and input the sampled input voltage to the inverting input of the second operational amplifier U2. Resistors R11 and R12 are used to sample the charging mapped voltage of battery 20 and input the sampled charging mapped voltage of battery 20 to the non-inverting input of the second operational amplifier U2.

[0090] Under normal charging conditions, the charging mapping voltage at the non-inverting input of the second operational amplifier U2 is less than the input voltage at the inverting input. Therefore, the output of the second operational amplifier U2 is low, the second switch Q2 is turned on, and the battery 20 continues to charge.

[0091] As the charging mapping voltage of battery 20 gradually increases, it indicates that battery 20 is slowly being fully charged. At this time, the charging mapping voltage at the non-inverting input gradually rises. When battery 20 is fully charged, the charging mapping voltage at the non-inverting input of the second operational amplifier U2 is greater than the input voltage at the inverting input. Therefore, the output of the second operational amplifier U2 outputs a high level, the square wave generator module does not work, the first operational amplifier in the square wave generator module continuously outputs a high level, the second switching transistor Q2 is turned off, and the charging of battery 20 ends.

[0092] It should be noted that resistor R9 is the charging current sampling resistor, and resistor R9 and diode D2 constitute a constant current charging circuit.

[0093] The aforementioned charging switch control module 11 includes an input voltage sampling unit 111, a battery voltage sampling unit 112, a charging comparison unit 113, and a switching unit 114. The input terminal of the input voltage sampling unit 111 is connected to the input power supply Vin and is used to sample the input voltage of Vin. The output terminal of the input voltage sampling unit 111 is connected to the first terminal of the switching unit 114 and the first input terminal of the charging comparison unit 113, respectively. The input terminal of the battery voltage sampling unit 112 is connected to the battery 20 and the second terminal of the switching unit 114, respectively. The output of the battery voltage sampling unit 112... The input voltage sampling unit 114 is connected to the second input terminal of the charging comparison unit 113 and is used to sample the charging mapped voltage of the battery 20. The output terminal of the charging comparison unit 113 is connected to the input terminal of the square wave generator module 12 and is used to compare the input voltage and the charging mapped voltage, and input a level signal to the square wave generator module 12 based on the comparison result. The third terminal of the switching unit 114 is connected to the output terminal of the square wave generator module 12, and the square wave signal output by the square wave generator module 12 is transmitted to the third terminal of the switching unit 114. The switching unit 114 is used to control the switching frequency connected to the battery 20 according to the period of the square wave signal. The input voltage sampling unit 111 is connected to the input power supply Vin and can collect the voltage value of the input power supply Vin in real time. Based on these sampled data, the charging comparison unit 113 determines whether the input voltage is within a safe and reasonable range. If the input voltage is too high or too low, the charging comparator unit 113 can take timely measures, such as controlling the switch unit 114 to cut off the charging path, to avoid overcharging, over-discharging, or damage to the battery 20 due to abnormal input voltage, thus building the first line of defense for charging the battery 20. Furthermore, the battery voltage sampling unit 112 is connected to the battery 20 to continuously monitor the voltage state of the battery 20. During charging, when the battery 20 voltage approaches or reaches the full charge voltage, the charging comparator unit 113 can output a high-level signal to turn off the switch unit. This allows the connection between the input power supply and the battery to be cut off after the battery is fully charged, preventing performance degradation and shortened lifespan caused by overcharging.

[0094] Furthermore, to facilitate monitoring and maintenance of the charging protection circuit 10, a charging display module 13 can also be provided in the charging protection circuit 10. In one embodiment, see further... Figure 2 As shown, the charging protection circuit 10 also includes a charging display module 13 for indicating and displaying the battery charging status based on the output result of the charging comparison unit 113. The charging display module 13 is connected to the output terminal of the charging comparison unit 113 and the input terminal of the square wave generator module, respectively.

[0095] In this embodiment, the charging display module 13 is mainly used to display the charging status of the battery 20 in real time. Specifically, the charging display module 13 may include two status indicator lights. When the battery 20 is charging, the first status indicator light is lit; when the battery 20 is fully charged, the second status indicator light is lit. Alternatively, the charging display module 13 may also use different colors of a single status indicator light to represent the status of the battery 20. When the battery 20 is charging, the status indicator light is lit in the first color; when the battery 20 is fully charged, the status indicator light is lit in the second color. This embodiment does not limit the display method of the charging display module 13.

[0096] Taking the charging display module 13, which includes two status indicator lights, as an example, in one embodiment, see below. Figure 2 The charging display module 13 includes resistor thirteen R13, resistor fourteen R14, first light-emitting diode LED1 and second light-emitting diode LED2;

[0097] The first end of resistor 13R13 is connected to the output end of battery voltage sampling unit 112 and the first end of switch unit 114, respectively; the second end of resistor 13R13 is connected to the first end of first light-emitting diode LED1.

[0098] The second terminal of the first light-emitting diode LED1 is connected to the first terminal of resistor R14 and the output terminal of charging comparator 113, respectively. The second terminal of resistor R14 is connected to the first terminal of the second light-emitting diode LED2, and the second terminal of the second light-emitting diode LED2 is grounded.

[0099] In this embodiment, the second terminal of the first light-emitting diode LED1 and the first terminal of resistor R14 are connected to the output terminal of the charging comparator unit 113 in the charging switch control module 11. Specifically, the charging comparator unit 113 outputs a low-level signal, indicating that the input power supply Vin is charging the battery 20. At this time, the first light-emitting diode LED1 is lit, the second light-emitting diode LED2 remains off, and resistor R13 limits the current of the first light-emitting diode LED1. The charging comparator unit 113 outputs a high-level signal, indicating that the battery 20 is fully charged. At this time, the second light-emitting diode LED2 is lit, the first light-emitting diode LED1 remains off, and resistor R14 limits the current of the second light-emitting diode LED2. Resistors R13 and R14 limit the current of the first light-emitting diode LED1 and the second light-emitting diode LED2 respectively to prevent excessive current from burning out the first light-emitting diode LED1 and the second light-emitting diode LED2.

[0100] The aforementioned charging protection circuit 10 further includes a charging display module 13 for indicating and displaying the battery charging status based on the output of the charging comparison unit 113. The charging display module 13 is connected to the output terminal of the charging comparison unit 113 and the input terminal of the square wave generator module. The charging display module 13 includes a resistor R13, a resistor R14, a first light-emitting diode (LED1), and a second light-emitting diode (LED2). The first terminal of the resistor R13 is connected to the output terminal of the battery voltage sampling unit 112 and the first terminal of the switching unit 114. The second terminal of the resistor R13 is connected to the first terminal of the first light-emitting diode (LED1). The second terminal of the first light-emitting diode (LED1) is connected to the first terminal of the resistor R14 and the output terminal of the charging comparison unit 113. The second terminal of the resistor R14 is connected to the first terminal of the second light-emitting diode (LED2), and the second terminal of the second light-emitting diode (LED2) is grounded. The charging display module 13 is connected to the charging switch control module 11 and the square wave generator module 12, and can reflect various state changes during the charging process in real time. Furthermore, the charging display module 13 presents the charging status to the user intuitively through the illumination of the first light-emitting diode LED1 and the second light-emitting diode LED2, enabling the user to clearly understand whether the battery 20 is fully charged, thus improving the user's perception of the charging process and the convenience of use.

[0101] The battery charging process will be described in detail below with reference to the above embodiments. After the input power supply Vin, the charging protection circuit 10, and the battery 20 are connected, the resistance values ​​of resistors R3 and R4 can be used to determine whether the input voltage of the input power supply Vin is within the charging voltage range. If it is not, it means that the input power supply Vin cannot charge the battery normally, and the first switch Q1 is turned off.

[0102] If the input power supply Vin is in the specified state, it indicates that the input power supply Vin can charge the battery normally. At this time, the voltage divided by resistors R3 and R4 is greater than the reference voltage, Zener diode D1 operates, and the first switching transistor Q1 is turned on. Resistor R5 provides operating current for Zener diode D1. The battery-mapped voltage input to the non-inverting input terminal of the second operational amplifier U2 is less than the input voltage input to the inverting input terminal of the second operational amplifier U2. At this time, the second operational amplifier U2 outputs a low-level signal, and the first light-emitting diode LED1 lights up. Resistor R13 provides current limiting for the first light-emitting diode LED1. The first operational amplifier U1 outputs a square wave signal, driving the second switching transistor Q2 to turn on. Thus, the input power supply Vin can charge battery 20 normally.

[0103] As the battery gradually charges, the battery-mapped voltage at the non-inverting input of the second operational amplifier U2 gradually increases. When the battery is fully charged, the battery-mapped voltage at the non-inverting input of the second operational amplifier U2 is greater than the input voltage at the inverting input. At this point, the second operational amplifier U2 continuously outputs a high-level signal, and the second light-emitting diode LED2 lights up. Resistor R14 provides current limiting for the second light-emitting diode LED2. The second switching transistor Q2 turns off, thus stopping the input power supply Vin from charging the battery 20.

[0104] In one embodiment, a charger is also provided, which includes the contents of any one of the embodiments of the charging protection circuit 10.

[0105] When charging battery 20 is required, the charger needs to connect the battery 20 to the input power source Vin so that the input power source Vin can charge the battery 20. The charger integrates a charging protection circuit 10, which prevents circuit failures or damage to the battery 20 due to overheating during charging, thus improving the safety of the charging process.

[0106] 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.

[0107] 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 application.

[0108] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this 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 application should be determined by the appended claims.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A charge protection circuit (10), characterized by, The charging protection circuit (10) comprises a charging switch control module (11) and a square wave generation module (12), a first end of the charging switch control module (11) is connected with an input power supply (Vin), a second end of the charging switch control module (11) is connected with an input end of the square wave generation module (12), an output end of the square wave generation module (12) is connected with a third end of the charging switch control module (11), a fourth end of the charging switch control module (11) is connected with a battery (20), and the square wave generation module (12) comprises a thermistor (RT). When the charging switch control module (11) controls the charging path to be conducted, the resistance value of the thermistor (RT) increases with the temperature rise, so as to adjust the period of the square wave signal input to the third end of the charging switch control module (11) by the square wave generation module (12), and the charging switch control module (11) is used for adjusting the switching frequency of the charging path according to the period of the square wave signal.

2. The circuit of claim 1, wherein, The square wave generation module (12) further comprises an operational amplification unit (121) and a capacitor (C), a first input end of the operational amplification unit (121) is connected with the second end of the charging switch control module (11), a first end of the capacitor (C) is connected with a second input end of the operational amplification unit (121), the thermistor (RT) is arranged between the second input end of the operational amplification unit (121) and an output end of the operational amplification unit (121), and a second end of the capacitor (C) is grounded.

3. The circuit of claim 2, wherein, The operational amplification unit (121) comprises a resistor one (R1), a resistor two (R2) and a first operational amplifier (U1), the resistor one (R1) is arranged between a non-inverting input end of the first operational amplifier (U1) and the second end of the charging switch control module (11), and the resistor two (R2) is arranged between the non-inverting input end of the first operational amplifier (U1) and an output end of the first operational amplifier (U1).

4. The circuit according to any one of claims 1 to 3, characterized in that The charging switch control module (11) comprises an input voltage sampling unit (111), a battery voltage sampling unit (112), a charging comparison unit (113) and a switching unit (114); An input end of the input voltage sampling unit (111) is connected with the input power supply (Vin) and is used for sampling the input voltage of the input power supply (Vin), and output ends of the input voltage sampling unit (111) are respectively connected with a first end of the switching unit (114) and a first input end of the charging comparison unit (113); An input end of the battery voltage sampling unit (112) is respectively connected with the battery (20) and a second end of the switching unit (114), an output end of the battery voltage sampling unit (112) is connected with a second input end of the charging comparison unit (113) and is used for sampling the charging mapping voltage of the battery (20); An input end of the charging comparison unit (113) is connected with the output end of the input voltage sampling unit (111) and the output end of the battery voltage sampling unit (112), and an output end of the charging comparison unit (113) is connected with a first input end of the switching unit (114) and a second input end of the charging switch control module (11); An output end of the charging comparison unit (113) is connected with an input end of the square wave generation module (12), and is used for comparing the input voltage and the charging mapping voltage, and outputting a level signal to the square wave generation module (12) based on a comparison result; A third end of the switch unit (114) is connected with an output end of the square wave generation module (12), and a square wave signal output by the square wave generation module (12) is transmitted to the third end of the switch unit (114), and the switch unit (114) is used for controlling a switch frequency in communication with the battery (20) according to a period of the square wave signal.

5. The circuit of claim 4, wherein, The input voltage sampling unit (111) comprises a resistor three (R3), a resistor four (R4), a resistor five (R5), a resistor six (R6), a voltage stabilizing tube (D1) and a first switch tube (Q1); A first end of the resistor three (R3), a first end of the resistor five (R5) and a first end of the first switch tube (Q1) are connected with the input power supply (Vin), and a second end of the resistor three (R3) is connected with a first end of the voltage stabilizing tube (D1) and a first end of the resistor four (R4) respectively; A second end of the first switch tube (Q1) is connected with a first input end of the charging comparison unit (113) and a first end of the switch unit (114) respectively, a third end of the first switch tube (Q1) is connected with a first end of the resistor six (R6), a second end of the resistor six (R6) and a second end of the resistor five (R5) are connected with a second end of the voltage stabilizing tube (D1) respectively, and a second end of the resistor four (R4) and a third end of the voltage stabilizing tube (D1) are grounded.

6. The circuit of claim 4, wherein, The charging comparison unit (113) comprises a resistor seven (R7), a resistor eight (R8) and a second operational amplifier (U2); A first end of the resistor seven (R7) is connected with an output end of the input voltage sampling unit (111) and a first end of the switch unit (114), a second end of the resistor seven (R7) and a first end of the resistor eight (R8) are connected with an inverting input end of the second operational amplifier (U2) respectively, a non-inverting input end of the second operational amplifier (U2) is connected with an output end of the battery voltage sampling unit (112), and an output end of the second operational amplifier (U2) is connected with an input end of the square wave generation module (12).

7. The circuit of claim 4, wherein, The switch unit comprises a resistor nine (R9), a resistor ten (R10), a diode (D2) and a second switch tube (Q2). The first end of the resistor nine (R9) and the first end of the diode (D2) are connected with the output end of the input voltage sampling unit (111), the second end of the resistor nine (R9) is connected with the first end of the second switch tube (Q2), the second end of the second switch tube (Q2) is connected with the input end of the battery voltage sampling unit (112) and the battery (20) respectively, the third end of the second switch tube (Q2) and the second end of the diode (D2) are connected with the first end of the resistor ten (R10), and the second end of the resistor ten (R10) is connected with the output end of the square wave generating module (12).

8. The circuit of claim 4, wherein, The battery voltage sampling unit (112) comprises a resistor eleven (R11) and a resistor twelve (R12), and the resistor twelve (R12) is a slide rheostat; The first end of the resistor eleven (R11) is connected with the second end of the switch unit (114) and the battery (20) respectively, the second end of the resistor eleven (R11) is connected with the first end of the resistor twelve (R12), and the second end of the resistor twelve (R12) is connected with the second input end of the charging comparison unit (113).

9. The circuit of claim 4, wherein, The charging protection circuit (10) further comprises a charging display module (13) for indicating and displaying the battery charging condition according to the output result of the charging comparison unit (113), and the charging display module (13) is connected with the output end of the charging comparison unit (113) and the input end of the square wave generating module respectively; The charging display module (13) comprises a resistor thirteen (R13), a resistor fourteen (R14), a first light emitting diode (LED1) and a second light emitting diode (LED2); The first end of the resistor thirteen (R13) is connected with the output end of the battery voltage sampling unit (112) and the first end of the switch unit (114), the second end of the resistor thirteen (R13) is connected with the first end of the first light emitting diode (LED1), The second end of the first light emitting diode (LED1) is connected with the first end of the resistor fourteen (R14) and the output end of the charging comparison unit (113) respectively, the second end of the resistor fourteen (R14) is connected with the first end of the second light emitting diode (LED2), and the second end of the second light emitting diode (LED2) is grounded.

10. A charger characterized by comprising: The charger comprises the charging protection circuit (10) in any one of the preceding claims 1-9.

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