Charging circuit of battery

Abstract

The utility model discloses a charging circuit of a battery, and relates to the technical field of charging equipment, the charging circuit comprises a power supply circuit, the input end of the power supply circuit receives a power supply, and the output end of the power supply circuit is used for charging the battery; the control circuit is respectively connected with the power supply circuit and the detection feedback circuit, the detection feedback circuit is connected with and detects the charging voltage of the power supply circuit, and the control circuit detects the charging voltage of the power supply circuit through the detection feedback circuit; when the charging voltage exceeds a first preset threshold value, the control circuit controls the power supply circuit to reduce the output, and when the charging voltage is lower than the first preset threshold value, the control circuit controls the power supply circuit to increase the output; when the environment temperature rises, the control circuit controls the power circuit to reduce the output, and when the environment temperature drops, the control circuit controls the power circuit to increase the output. According to the invention, the charging electric quantity of the lead-acid battery in a low-temperature environment is more sufficient, and the lead-acid battery is prevented from being overcharged in a high-temperature environment.

Description

Technical Field

[0001] The utility model relates to the technical field of charging equipment, in particular to a charging circuit of a battery. Background Art

[0002] Lead-acid battery (VRLA) is a storage battery whose electrodes are mainly made of lead and its oxides, and whose electrolyte is sulfuric acid solution. When the lead-acid battery is in the discharge state, the main component of the positive electrode is lead dioxide, and the main component of the negative electrode is lead; when it is in the charging state, the main components of the positive and negative electrodes are both lead sulfate.

[0003] As the temperature decreases, the capacity of the lead-acid battery will gradually decrease. This is because the charging efficiency of the lead-acid battery will be affected in a low temperature environment. This is mainly because the low temperature reduces the fluidity of the electrolyte, slowing down the diffusion of ions during the charging process, thus affecting the charging efficiency. On the other hand, as the temperature rises, the capacity of the lead-acid battery will gradually increase, and the charging and discharging efficiency will increase, which may lead to overcharging of the battery, and overcharging of the battery may cause safety accidents. Therefore, insufficient charging in a low temperature environment and overcharging of the battery in a high temperature environment are problems that need to be solved. Utility Model Content

[0004] The purpose of the utility model is to provide a battery charging circuit, which can make the lead-acid battery charge more fully in a low temperature environment and prevent the lead-acid battery from being overcharged in a high temperature environment.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0006] One aspect of an embodiment of the utility model provides a charging circuit for a battery, the charging circuit comprising: a power supply circuit, the input end of the power supply circuit is used to receive power, and the output end of the power supply circuit is used to charge the battery; a detection feedback circuit and a control circuit, the control circuit is respectively connected to the power supply circuit and the detection feedback circuit, the detection feedback circuit is connected to detect the charging voltage of the power supply circuit, and the control circuit detects the charging voltage of the power supply circuit through the detection feedback circuit; when the charging voltage exceeds a first preset threshold value, the control circuit controls the power supply circuit to reduce the output, and when the charging voltage is lower than the first preset threshold value, the control circuit controls the power supply circuit to increase the output; the first preset threshold value changes in real time according to the ambient temperature, and the first preset threshold value is inversely proportional to the ambient temperature.

[0007] In some embodiments, the detection feedback circuit includes a thermistor, a first resistor, a second resistor, a third resistor, a fourth resistor, an optocoupler and a first voltage-regulating diode, one end of the first resistor and one end of the third resistor are connected to the power supply circuit, the other end of the first resistor is connected to one end of the thermistor, the other end of the thermistor is connected to a reference end of the first voltage-regulating diode and one end of the second resistor, the other end of the second resistor and the anode of the first voltage-regulating diode are connected to a first location, the other end of the third resistor is connected to the input end of the light-emitting end of the optocoupler, the output end of the light-emitting end of the optocoupler is connected to the cathode of the first voltage-regulating diode, the input end of the light-receiving end of the optocoupler is connected to the control circuit through the fourth resistor, and the output end of the light-receiving end of the optocoupler is connected to a second location.

[0008] In some embodiments, the detection feedback circuit also includes a first diode, a comparator, a fifth resistor, a sixth resistor, a seventh resistor and a first capacitor, the positive electrode of the first diode is connected to the output end of the optocoupler light-emitting end, the negative electrode of the first diode is connected to one end of the first capacitor and the output end of the comparator, the other end of the first capacitor is connected to the inverting input end of the comparator and one end of the sixth resistor through the fifth resistor, the other end of the sixth resistor is connected to one end of the seventh resistor and the negative electrode of the battery, the other end of the seventh resistor is connected to the first location, and the non-inverting input end of the comparator is used to receive a reference voltage signal.

[0009] In some embodiments, the detection feedback circuit also includes an eighth resistor, a ninth resistor, a tenth resistor, a second zener diode and a second capacitor, one end of the eighth resistor is connected to a power supply, the other end of the eighth resistor is connected to one end of the ninth resistor, the cathode of the second zener diode, the reference end of the second zener diode and one end of the second capacitor, the other end of the ninth resistor is connected to one end of the tenth resistor and the in-phase input terminal of the comparator, the other end of the tenth resistor, the anode of the second zener diode and the other end of the second capacitor are all connected to a first location, and the ninth resistor and the tenth resistor output a reference voltage signal to the in-phase input terminal of the comparator after voltage division.

[0010] In some embodiments, the power supply circuit includes a transformer, a rectifier and filter circuit and a second diode. The input end of the rectifier and filter circuit receives power, the positive output end of the rectifier and filter circuit is connected to the first end of the primary coil of the transformer, the second end of the primary coil of the transformer is connected to the control circuit, the first end of the secondary coil of the transformer is connected to the positive electrode of the second diode, the negative electrode of the second diode is connected to the detection feedback circuit, the negative electrode of the second diode is used to provide a charging voltage to the positive electrode of the battery after filtering, the second end of the secondary coil of the transformer is used as the first location, and the two ends of the auxiliary coil of the transformer are connected to the control circuit.

[0011] In some embodiments, the power supply circuit also includes a fourth capacitor, a fifth capacitor and an inductor, the positive electrode of the fourth capacitor is connected to the negative electrode of the second diode and one end of the inductor, the other end of the inductor is connected to the positive electrode of the fifth capacitor and the positive electrode of the battery, and the negative electrode of the fourth capacitor and the negative electrode of the fifth capacitor are connected to the first location.

[0012] In some embodiments, the power supply circuit also includes an eleventh resistor and a third capacitor, one end of the eleventh resistor is connected to the positive electrode of the second diode and the first end of the secondary coil of the transformer, the other end of the eleventh resistor is connected to one end of the third capacitor, and the other end of the third capacitor is connected to the negative electrode of the second diode.

[0013] In some embodiments, the rectification and filtering circuit includes a rectifier bridge, a sixth capacitor, a seventh capacitor, a twelfth resistor and a third diode. The input end of the rectifier bridge receives an AC power supply, the positive output end of the rectifier bridge is connected to the positive electrode of the sixth capacitor, the control circuit, one end of the seventh capacitor, one end of the twelfth resistor and the first end of the primary coil of the transformer, the negative output end of the rectifier bridge is connected to the negative electrode of the sixth capacitor, the negative output end of the rectifier bridge serves as a second location, the second end of the primary coil of the transformer is connected to the positive electrode of the third diode and the control circuit, and the negative electrode of the third diode is connected to the other end of the twelfth resistor and the other end of the seventh capacitor.

[0014] In some embodiments, the control circuit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a fourth diode, an eighth capacitor and a main control chip, one end of the thirteenth resistor is connected to the positive output end of the rectifier bridge, the other end of the thirteenth resistor is connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is connected to the power input end of the main control chip, the positive electrode of the eighth capacitor and one end of the fifteenth resistor, the other end of the fifteenth resistor is connected to the negative electrode of the fourth diode, the positive electrode of the fourth diode is connected to the first end of the auxiliary coil of the transformer, the second end of the auxiliary coil of the transformer is connected to the location input end of the main control chip, the negative electrode and the second location of the eighth capacitor, the control output end of the main control chip is connected to the second end of the primary coil of the transformer, and the feedback end of the main control chip is connected to the detection feedback circuit.

[0015] In some embodiments, the control circuit also includes a sixteenth resistor and a seventeenth resistor, one end of the sixteenth resistor is connected to the first end of the auxiliary coil of the transformer, one end of the seventeenth resistor is connected to the second end of the auxiliary coil of the transformer, and the other end of the sixteenth resistor and the other end of the seventeenth resistor are connected to the detection control input end of the main control chip; when the main control chip detects that the voltage of the auxiliary coil of the transformer exceeds a second preset threshold value, the main control chip controls the primary coil of the transformer to stop working.

[0016] A battery charging circuit according to an embodiment of the utility model has at least the following beneficial effects: when the ambient temperature rises, the control circuit controls the power supply circuit to reduce the charging voltage of the battery; when the ambient temperature decreases, the control circuit controls the power supply circuit to increase the charging voltage, so that the battery can be charged more fully in a low temperature environment, and the battery can be prevented from being overcharged in a high temperature environment.

[0017] When the charging voltage exceeds the first preset threshold, the control circuit controls the power supply circuit to reduce the charging voltage. When the charging voltage is lower than the first preset threshold, the control circuit controls the power supply circuit to increase the charging voltage, so as to make the charging voltage more stable and increase the service life of the battery.

[0018] When the main control chip detects that the voltage of the auxiliary coil of the transformer exceeds the second preset threshold, the main control chip controls the primary coil of the transformer to stop working to prevent the occurrence of safety accidents caused by excessive charging voltage.

[0019] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. 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 paying any creative work.

[0021] Figure 1 is a schematic diagram of a charging circuit according to an embodiment. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] The terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present disclosure will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0026] The technical solution of the embodiment of the present application is briefly described below:

[0027] According to some embodiments, Figure 1 As shown, the present application provides a battery charging circuit, the charging circuit comprising:

[0028] A power circuit, wherein an input end of the power circuit is used to receive power, and an output end of the power circuit is used to charge a battery;

[0029] The first preset threshold value changes in real time according to the ambient temperature, and the first preset threshold value is inversely proportional to the ambient temperature.

[0030] Based on the working principle of the above embodiment, the control circuit detects the charging voltage of the power supply circuit through the detection feedback circuit. When the charging voltage exceeds the first preset threshold, the detection feedback circuit feeds back a signal that the charging voltage exceeds the first preset threshold to the control circuit, and the control circuit controls the power supply circuit to reduce the output to prevent the charging voltage from being too high. When the charging voltage is lower than the first preset threshold, the detection feedback circuit feeds back a signal that the charging voltage is lower than the first preset threshold to the control circuit, and the control circuit controls the power supply circuit to increase the output to prevent the charging voltage from being too low. This allows the charging voltage to be stabilized within the first preset threshold, further increasing the service life of the battery.

[0031] When the ambient temperature rises, the detection feedback circuit feeds back a signal of high ambient temperature to the control circuit, and the control circuit controls the power circuit to reduce the output. When the ambient temperature drops, the detection feedback circuit feeds back a signal of low ambient temperature to the control circuit, and the control circuit controls the power circuit to increase the output. This allows the battery to have more charging power in a low temperature environment, and prevents the battery from being overcharged in a high temperature environment. The first preset threshold changes with the change of ambient temperature.

[0032] Among them, the first preset threshold can be set according to actual needs.

[0033] The following is combined with the appendix of this manual Figure 1 , the preferred implementation modes of the present disclosure are further elaborated in detail.

[0034] According to some embodiments, Figure 1 As shown, the detection feedback circuit includes a thermistor RR, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, an optical coupler OPT and a first voltage regulator diode U1, and its connection structure is as follows:

[0035] One end of the first resistor R1 and one end of the third resistor R3 are connected to the power supply circuit, the other end of the first resistor R1 is connected to one end of the thermistor RR, the other end of the thermistor RR is connected to the reference end of the first voltage zener diode U1 and one end of the second resistor R2, the other end of the second resistor R2 and the anode of the first voltage zener diode U1 are connected to a first location, the other end of the third resistor R3 is connected to the input end of the light emitting end of the optocoupler OPT, the output end of the light emitting end of the optocoupler OPT is connected to the cathode of the first voltage zener diode U1, the input end of the light receiving end of the optocoupler OPT is connected to the control circuit through the fourth resistor R4, and the output end of the light receiving end of the optocoupler OPT is connected to the second location.

[0036] Based on the working principle of the above embodiment, when the voltage of the power supply circuit increases, the reference terminal voltage of the first voltage zener diode U1 increases, the first voltage zener diode U1 is turned on, the light-emitting end of the optocoupler OPT emits light, the light-receiving end of the optocoupler OPT is turned on, the control circuit receives a low-level signal, and the control circuit controls the power supply circuit to reduce the output.

[0037] When the voltage of the power supply circuit decreases, the reference terminal voltage of the first voltage zener diode U1 decreases, the first voltage zener diode U1 is turned off, the light-emitting end of the optocoupler OPT does not emit light, the light-receiving end of the optocoupler OPT is cut off, the control circuit does not receive a low-level signal, and the control circuit controls the power supply circuit to increase the output.

[0038] When the ambient temperature rises, the resistance of the thermistor RR decreases, the reference terminal voltage of the first voltage zener diode U1 increases, the first voltage zener diode U1 is turned on, the light-emitting end of the optocoupler OPT emits light, the light-receiving end of the optocoupler OPT is turned on, the control circuit receives a low-level signal, and the control circuit controls the power supply circuit to reduce the output.

[0039] When the ambient temperature decreases, the resistance of the thermistor RR increases, the reference terminal voltage of the first voltage zener diode U1 decreases, the first voltage zener diode U1 is turned off, the light-emitting end of the optocoupler OPT does not emit light, the light-receiving end of the optocoupler OPT is cut off, the control circuit does not receive a low-level signal, and the control circuit controls the power supply circuit to increase the output.

[0040] Furthermore, in some embodiments, Figure 1 As shown, the detection feedback circuit further adds a resistor R18 and a resistor R19, the resistor R18 is connected in parallel with the thermistor RR, and the resistor R19 is connected in parallel with the light-emitting end of the optocoupler OPT, wherein the resistor R18 is used for voltage division and current shunting, and the resistor R19 is used for current shunting.

[0041] According to some embodiments, Figure 1 As shown, in addition to the above structure, the detection feedback circuit further includes a first diode D1, a comparator UA, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a first capacitor C1, and its connection structure is as follows:

[0042] The anode of the first diode D1 is connected to the output end of the light-emitting end of the optocoupler OPT, the cathode of the first diode D1 is connected to one end of the first capacitor C1 and the output end of the comparator UA, the other end of the first capacitor C1 is connected to the inverting input end of the comparator UA and one end of the sixth resistor R6 through the fifth resistor R5, the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and the negative electrode of the battery, the other end of the seventh resistor R7 is connected to the first location, and the non-inverting input end of the comparator UA is used to receive a reference voltage signal.

[0043] Based on the working principle of the above embodiment, when the charging voltage is too high, the voltage given by the negative electrode of the battery to the inverting input terminal of the comparator UA through the sixth resistor R6 is higher than the reference voltage of the non-inverting input terminal of the comparator UA, and the comparator UA outputs a low level, the light-emitting end of the optocoupler OPT is turned on through the first diode D1, the light-emitting end of the optocoupler OPT emits light, the light-receiving end of the optocoupler OPT is turned on, and the control circuit receives a low-level signal through the light-receiving end of the optocoupler OPT, and the control circuit controls the power supply circuit to reduce the output.

[0044] When the charging voltage is too low, the voltage given by the negative electrode of the battery to the inverting input terminal of the comparator UA through the sixth resistor R6 is lower than the reference voltage of the non-inverting input terminal of the comparator UA, the comparator UA outputs a high level, the light-emitting end of the optocoupler OPT does not emit light, the light-receiving end of the optocoupler OPT is cut off, the control circuit does not detect a low-level signal through the light-receiving end of the optocoupler OPT, and the control circuit controls the power supply circuit to increase the output.

[0045] According to some embodiments, Figure 1 As shown, in addition to the above structure, the detection feedback circuit also includes a reference voltage circuit for generating a reference voltage signal. The reference voltage circuit includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a second voltage stabilizing diode U2 and a second capacitor C2, and its connection structure is as follows:

[0046] One end of the eighth resistor R8 is connected to the power supply, the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9, the cathode of the second voltage zener diode U2, the reference end of the second voltage zener diode U2 and one end of the second capacitor C2, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the non-inverting input end of the comparator UA, the other end of the tenth resistor R10, the anode of the second voltage zener diode U2 and the other end of the second capacitor C2 are all connected to the first location, and the ninth resistor R9 and the tenth resistor R10 output a reference voltage signal to the non-inverting input end of the comparator UA after voltage division.

[0047] The first voltage zener diode U1 and the second voltage zener diode U2 are TL431.

[0048] According to some embodiments, Figure 1As shown, the power supply circuit includes a transformer T, a rectifier and filter circuit and a second diode D2. The input end of the rectifier and filter circuit receives power, the positive output end of the rectifier and filter circuit is connected to the first end of the primary coil of the transformer T, the second end of the primary coil of the transformer T is connected to the control circuit, the first end of the secondary coil of the transformer T is connected to the positive electrode of the second diode D2, the negative electrode of the second diode D2 is connected to the detection feedback circuit, the negative electrode of the second diode D2 is used to provide a charging voltage to the positive electrode of the battery after filtering, the second end of the secondary coil of the transformer T is used as the first location, and the two ends of the auxiliary coil of the transformer T are connected to the control circuit.

[0049] The transformer T is used for stepping down the voltage, and the auxiliary coil of the transformer T is used for controlling the circuit to detect the voltage of the power supply circuit; the second diode D2 is used for rectifying the electrical signal of the secondary coil of the transformer T.

[0050] According to some embodiments, Figure 1 As shown, the power supply circuit also includes a fourth capacitor C4, a fifth capacitor C5 and an inductor L, the positive electrode of the fourth capacitor C4 is connected to the negative electrode of the second diode D2 and one end of the inductor L, the other end of the inductor L is connected to the positive electrode of the fifth capacitor C5 and the positive electrode of the battery, and the negative electrode of the fourth capacitor C4 and the negative electrode of the fifth capacitor C5 are connected to the first location.

[0051] The fourth capacitor C4, the fifth capacitor C5 and the inductor L are used for filtering the charging voltage, so that the charging voltage of the battery is more stable.

[0052] According to some embodiments, Figure 1 As shown, in addition to the above structure, the power supply circuit also includes an eleventh resistor R11 and a third capacitor C3, one end of the eleventh resistor R11 is connected to the positive electrode of the second diode D2 and the first end of the secondary coil of the transformer T, the other end of the eleventh resistor R11 is connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is connected to the negative electrode of the second diode D2, one end of the first resistor R1 and one end of the third resistor R3.

[0053] The eleventh resistor R11 and the third capacitor C3 are used to absorb the peak current.

[0054] According to some embodiments, Figure 1 As shown, the rectifier and filter circuit includes a rectifier bridge DB, a sixth capacitor C6, a seventh capacitor C7, a twelfth resistor R12 and a third diode D3, and its connection structure is as follows:

[0055] The input end of the rectifier bridge DB receives an AC power supply, the positive output end of the rectifier bridge DB is connected to the positive electrode of the sixth capacitor C6, the control circuit, one end of the seventh capacitor C7, one end of the twelfth resistor R12 and the first end of the primary coil of the transformer T, the negative output end of the rectifier bridge DB is connected to the negative electrode of the sixth capacitor C6, the negative output end of the rectifier bridge DB serves as the second location, the second end of the primary coil of the transformer T is connected to the positive electrode of the third diode D3 and the control circuit, and the negative electrode of the third diode D3 is connected to the other end of the twelfth resistor R12 and the other end of the seventh capacitor C7.

[0056] According to some embodiments, Figure 1 As shown, the control circuit includes a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a fourth diode D4, an eighth capacitor C8 and a main control chip U3, and its connection structure is as follows:

[0057] One end of the thirteenth resistor R13 is connected to the positive output end of the rectifier bridge DB, the other end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14, the other end of the fourteenth resistor R14 is connected to the power input end VDD of the main control chip U3, the positive electrode of the eighth capacitor C8 and one end of the fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected to the cathode of the fourth diode D4, the anode of the fourth diode D4 is connected to the first end of the auxiliary coil of the transformer T, the second end of the auxiliary coil of the transformer T is connected to the location input end of the main control chip U3, the negative electrode of the eighth capacitor C8 and the second location, the control output end D of the main control chip U3 is connected to the second end of the primary coil of the transformer T, and the feedback end VFB of the main control chip U3 is connected to the light receiving end input end of the optocoupler OPT through the fourth resistor R4.

[0058] Among them, the thirteenth resistor R13 and the fourteenth resistor R14 are used for voltage division and then supplying power to the main control chip U3, the eighth capacitor C8 is used for filtering, the fifteenth resistor R15 is used for current limiting, and the fourth diode D4 is used for rectification.

[0059] According to some embodiments, Figure 1 As shown, in addition to the above structure, the control circuit also includes a sixteenth resistor R16 and a seventeenth resistor R17, one end of the sixteenth resistor R16 is connected to the first end of the auxiliary coil of the transformer T, one end of the seventeenth resistor R17 is connected to the second end of the auxiliary coil of the transformer T, and the other end of the sixteenth resistor R16 and the other end of the seventeenth resistor R17 are connected to the detection control input terminal BIO of the main control chip U3;

[0060] When the main control chip U3 detects that the voltage of the auxiliary coil of the transformer T exceeds the second preset threshold, the main control chip U3 controls the primary coil of the transformer T to stop working.

[0061] Based on the working principle of the above embodiment, the control circuit detects the voltage of the auxiliary coil of the transformer T, and the voltage of the auxiliary coil of the transformer T can reflect the voltage of the primary coil of the transformer T and the voltage of the secondary coil of the transformer T. When the voltage of the auxiliary coil of the transformer T is too high and exceeds the second preset threshold, it means that the voltage of the primary coil of the transformer T and the voltage of the secondary coil of the transformer T are too high, and the control circuit controls the primary coil of the transformer T to be powered off, and the transformer T stops working. This prevents the occurrence of safety accidents caused by excessive charging voltage.

[0062] The second preset threshold can be set according to actual needs.

[0063] Further, such as Figure 1 As shown, in addition to the above structure, the control circuit also includes a capacitor C9 and a resistor R20. One end of the capacitor C9 is connected to the light receiving input end of the optical coupler OPT through the fourth resistor R4, and one end of the capacitor C9 is also connected to the feedback end VFB of the main control chip U3. The other end of the capacitor C9 is connected to the second location for filtering; one end of the resistor R20 is connected to the CS pin of the main control chip U3, and the other end of the resistor R20 is connected to the second location for internal grounding of the main control chip U3 to form a loop.

[0064] like Figure 1 As shown, the working principle of this application is:

[0065] When the detection control input terminal BIO of the main control chip U3 detects that the auxiliary coil of the transformer T is higher than the second preset threshold through the sixteenth resistor R16 and the seventeenth resistor R17, the main control chip U3 controls the primary coil of the transformer T to be powered off through the control output terminal D, and the transformer T stops working, so as to prevent the occurrence of safety accidents caused by excessive charging voltage.

[0066] At normal temperature:

[0067] When the cathode voltage of the second diode D2 increases and exceeds the first preset threshold value, the reference terminal voltage of the first voltage zener diode U1 increases, the first voltage zener diode U1 is turned on, the light-emitting end of the optocoupler OPT emits light, the light-receiving end of the optocoupler OPT is turned on, and the feedback end VFB of the main control chip U3 receives a low-level signal. The main control chip U3 controls the primary coil of the transformer T by controlling the output end D to reduce the output, thereby further reducing the charging voltage.

[0068] When the cathode voltage of the second diode D2 drops below the first preset threshold, the reference terminal voltage of the first voltage zener diode U1 drops, the first voltage zener diode U1 is turned off, the light-emitting end of the optocoupler OPT does not emit light, the light-receiving end of the optocoupler OPT is cut off, and the feedback end VFB of the main control chip U3 does not receive a low-level signal. The main control chip U3 controls the primary coil of the transformer T by controlling the output end D to increase the output, thereby further increasing the charging voltage.

[0069] In high temperature environment:

[0070] When the ambient temperature rises, the resistance of thermistor RR decreases, the reference terminal voltage of the first voltage stabilizing diode U1 increases, the first voltage stabilizing diode U1 is turned on, the light-emitting end of the optocoupler OPT emits light, the light-receiving end of the optocoupler OPT is turned on, the feedback end VFB of the main control chip U3 receives a low-level signal, and the main control chip U3 controls the primary coil of the transformer T through the control output end D to reduce the output, thereby further reducing the charging voltage. This is equivalent to reducing the first preset threshold value when the temperature rises.

[0071] In low temperature environment:

[0072] When the ambient temperature decreases, the resistance of the thermistor RR increases, the reference terminal voltage of the first voltage zener diode U1 decreases, the first voltage zener diode U1 is turned off, the light-emitting end of the optocoupler OPT does not emit light, the light-receiving end of the optocoupler OPT is cut off, the feedback end VFB of the main control chip U3 does not receive a low-level signal, and the main control chip U3 controls the primary coil of the transformer T by controlling the output end D to increase the output, thereby further increasing the charging voltage.

[0073] When the ambient temperature decreases and the charging voltage is too high, at this time, the resistance of thermistor RR increases, so that the first preset threshold value increases, and the voltage cannot be reduced by turning on the first voltage stabilizing diode U1. Therefore, at this time, when the charging voltage is too high, the voltage given by the negative electrode of the battery to the inverting input terminal of the comparator UA through the sixth resistor R6 is higher than the reference voltage of the inverting input terminal of the comparator UA, and the comparator UA outputs a low level, the light-emitting end of the optocoupler OPT is turned on through the first diode D1, the light-emitting end of the optocoupler OPT emits light, the light-receiving end of the optocoupler OPT is turned on, and the feedback end VFB of the main control chip U3 receives a low-level signal through the light-receiving end of the optocoupler OPT. The main control chip U3 controls the primary coil of the transformer T by controlling the output end D to reduce the output, thereby further reducing the charging voltage. As the temperature decreases, the capacity of the lead-acid battery will gradually decrease. This is because the charging efficiency of the lead-acid battery will be affected in a low temperature environment. This is mainly because the low temperature reduces the fluidity of the electrolyte, slowing down the diffusion rate of ions during the charging process, thereby affecting the charging efficiency. Therefore, when the ambient temperature decreases, the first voltage regulator diode U1 is turned off to increase the charging voltage. However, if the charging voltage is too high, it is necessary to reduce the voltage by outputting a low-level signal through the comparator UA.

[0074] Furthermore, when the charging voltage is too low, the voltage provided by the negative electrode of the battery to the inverting input terminal of the comparator UA through the sixth resistor R6 is lower than the reference voltage of the non-inverting input terminal of the comparator UA, and the comparator UA outputs a high level. The light-emitting end of the optocoupler OPT does not emit light, and the light-receiving end of the optocoupler OPT is cut off. The feedback end VFB of the main control chip U3 does not detect a low-level signal through the light-receiving end of the optocoupler OPT. The main control chip U3 controls the primary coil of the transformer T through the control output end D to increase the output, thereby further increasing the charging voltage.

[0075] Therefore, in the present application, the charging voltage of the battery is adjusted by the output of the comparator UA in a low temperature environment. In a normal temperature environment and a high temperature environment, the charging voltage of the battery is adjusted by turning on and off the first voltage stabilizing diode U1. In a low temperature environment, the charging voltage of the battery can reach a relatively high voltage value, and the relatively high voltage value can be stabilized by adjusting the comparator UA.

[0076] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0077] Although the present disclosure has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present disclosure can be implemented in a variety of forms without departing from the spirit or essence of the present application, it should be understood that the above-mentioned embodiments are not limited to any of the foregoing details, but should be widely interpreted within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A battery charging circuit, characterized in that: The charging circuit comprises: A power circuit, wherein an input end of the power circuit is used to receive power, and an output end of the power circuit is used to charge a battery; a detection feedback circuit and a control circuit, wherein the control circuit is connected to the power circuit and the detection feedback circuit respectively, the detection feedback circuit is connected to detect the charging voltage of the power circuit, and the control circuit detects the charging voltage of the power circuit through the detection feedback circuit; When the charging voltage exceeds a first preset threshold, the control circuit controls the power supply circuit to reduce output, and when the charging voltage is lower than the first preset threshold, the control circuit controls the power supply circuit to increase output; The first preset threshold value changes in real time according to the ambient temperature, and the first preset threshold value is inversely proportional to the ambient temperature.

2. The charging circuit according to claim 1, characterized in that: The detection feedback circuit includes a thermistor, a first resistor, a second resistor, a third resistor, a fourth resistor, an optocoupler and a first voltage-regulating diode, one end of the first resistor and one end of the third resistor are connected to the power supply circuit, the other end of the first resistor is connected to one end of the thermistor, the other end of the thermistor is connected to the reference end of the first voltage-regulating diode and one end of the second resistor, the other end of the second resistor and the anode of the first voltage-regulating diode are connected to a first location, the other end of the third resistor is connected to the input end of the light-emitting end of the optocoupler, the output end of the light-emitting end of the optocoupler is connected to the cathode of the first voltage-regulating diode, the input end of the light-receiving end of the optocoupler is connected to the control circuit through the fourth resistor, and the output end of the light-receiving end of the optocoupler is connected to a second location.

3. The charging circuit according to claim 2, characterized in that: The detection feedback circuit also includes a first diode, a comparator, a fifth resistor, a sixth resistor, a seventh resistor and a first capacitor, the positive electrode of the first diode is connected to the output end of the optocoupler light-emitting end, the negative electrode of the first diode is connected to one end of the first capacitor and the output end of the comparator, the other end of the first capacitor is connected to the inverting input end of the comparator and one end of the sixth resistor through the fifth resistor, the other end of the sixth resistor is connected to one end of the seventh resistor and the negative electrode of the battery, the other end of the seventh resistor is connected to the first location, and the non-inverting input end of the comparator is used to receive a reference voltage signal.

4. The charging circuit according to claim 3, characterized in that: The detection feedback circuit also includes an eighth resistor, a ninth resistor, a tenth resistor, a second voltage-stabilizing diode and a second capacitor. One end of the eighth resistor is connected to a power supply, and the other end of the eighth resistor is connected to one end of the ninth resistor, the cathode of the second voltage-stabilizing diode, the reference end of the second voltage-stabilizing diode and one end of the second capacitor. The other end of the ninth resistor is connected to one end of the tenth resistor and the non-inverting input end of the comparator, and the other end of the tenth resistor, the anode of the second voltage-stabilizing diode and the other end of the second capacitor are all connected to a first location. The ninth resistor and the tenth resistor output a reference voltage signal to the non-inverting input end of the comparator after voltage division.

5. The charging circuit according to claim 1, characterized in that: The power supply circuit includes a transformer, a rectifier and filter circuit and a second diode. The input end of the rectifier and filter circuit receives power, the positive output end of the rectifier and filter circuit is connected to the first end of the primary coil of the transformer, the second end of the primary coil of the transformer is connected to the control circuit, the first end of the secondary coil of the transformer is connected to the positive electrode of the second diode, the negative electrode of the second diode is connected to the detection feedback circuit, the negative electrode of the second diode is used to provide a charging voltage to the positive electrode of the battery after filtering, the second end of the secondary coil of the transformer is used as the first location, and the two ends of the auxiliary coil of the transformer are connected to the control circuit.

6. The charging circuit according to claim 5, characterized in that: The power supply circuit also includes a fourth capacitor, a fifth capacitor and an inductor, the positive electrode of the fourth capacitor is connected to the negative electrode of the second diode and one end of the inductor, the other end of the inductor is connected to the positive electrode of the fifth capacitor and the positive electrode of the battery, and the negative electrode of the fourth capacitor and the negative electrode of the fifth capacitor are connected to the first location.

7. The charging circuit according to claim 5, characterized in that: The power supply circuit also includes an eleventh resistor and a third capacitor, one end of the eleventh resistor is connected to the positive electrode of the second diode and the first end of the secondary coil of the transformer, the other end of the eleventh resistor is connected to one end of the third capacitor, and the other end of the third capacitor is connected to the negative electrode of the second diode.

8. The charging circuit according to claim 5, characterized in that: The rectification and filtering circuit includes a rectifier bridge, a sixth capacitor, a seventh capacitor, a twelfth resistor and a third diode. The input end of the rectifier bridge receives an AC power supply. The positive output end of the rectifier bridge is connected to the positive electrode of the sixth capacitor, the control circuit, one end of the seventh capacitor, one end of the twelfth resistor and the first end of the primary coil of the transformer. The negative output end of the rectifier bridge is connected to the negative electrode of the sixth capacitor. The negative output end of the rectifier bridge serves as a second location. The second end of the primary coil of the transformer is connected to the positive electrode of the third diode and the control circuit. The negative electrode of the third diode is connected to the other end of the twelfth resistor and the other end of the seventh capacitor.

9. The charging circuit according to claim 8, characterized in that: The control circuit includes a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a fourth diode, an eighth capacitor and a main control chip, one end of the thirteenth resistor is connected to the positive output end of the rectifier bridge, the other end of the thirteenth resistor is connected to one end of the fourteenth resistor, the other end of the fourteenth resistor is connected to the power input end of the main control chip, the positive electrode of the eighth capacitor and one end of the fifteenth resistor, the other end of the fifteenth resistor is connected to the negative electrode of the fourth diode, the positive electrode of the fourth diode is connected to the first end of the auxiliary coil of the transformer, the second end of the auxiliary coil of the transformer is connected to the location input end of the main control chip, the negative electrode and the second location of the eighth capacitor, the control output end of the main control chip is connected to the second end of the primary coil of the transformer, and the feedback end of the main control chip is connected to the detection feedback circuit.

10. The charging circuit according to claim 9, characterized in that: The control circuit further includes a sixteenth resistor and a seventeenth resistor, one end of the sixteenth resistor is connected to the first end of the auxiliary coil of the transformer, one end of the seventeenth resistor is connected to the second end of the auxiliary coil of the transformer, and the other end of the sixteenth resistor and the other end of the seventeenth resistor are connected to the detection control input end of the main control chip; When the main control chip detects that the voltage of the auxiliary coil of the transformer exceeds a second preset threshold, the main control chip controls the primary coil of the transformer to stop working.

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