CN211958802U - Lithium battery charging circuit - Google Patents
Lithium battery charging circuit Download PDFInfo
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- CN211958802U CN211958802U CN202020282686.9U CN202020282686U CN211958802U CN 211958802 U CN211958802 U CN 211958802U CN 202020282686 U CN202020282686 U CN 202020282686U CN 211958802 U CN211958802 U CN 211958802U
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Abstract
The application discloses lithium battery charging circuit, including mains voltage detection module, control module, battery voltage detection module and the regulation module that charges, wherein: one end of the power supply voltage detection module is connected with a power supply, and the other end of the power supply voltage detection module is connected with the control module; one end of the battery voltage detection module is connected with a battery to be charged, and the other end of the battery voltage detection module is connected with the control module; the control module is connected with the charging adjusting module. Above-mentioned lithium battery charging circuit detects through supply voltage and battery voltage simultaneously to adjust charging current based on the testing result, avoid supply voltage too big or battery to be full of the back and continue to charge the battery damage that leads to, it is safer.
Description
Technical Field
The application relates to the technical field of lithium batteries, in particular to a lithium battery charging circuit.
Background
A battery is an electronic component widely used in the industrial field, and among various batteries, a lithium battery is increasingly recognized by users due to its characteristics such as high cell voltage, high energy density, small size, light weight, long cycle life, no memory effect, and the like. Although the voltage of a single lithium battery can reach 4.2V, the single lithium battery can not meet the requirement in many occasions, so that a single lithium battery is required to be combined into a lithium battery pack with the voltage and the capacity meeting the use requirement in a series-parallel connection mode. The technology for charging the lithium battery pack is developed.
The characteristics of lithium battery determine that it can not be charged by using the common charging technology of battery (such as storage battery), and the charging current should be limited during the charging process (the maximum value is not more than 1C)5A) And the charging voltage (the charging limit voltage of a single lithium battery is usually 4.2V), otherwise the lithium battery is likely to be swelled and even exploded. At present, a charging technology suitable for lithium battery charging exists, but most of the traditional charging technologies are charging technologies which use alternating current mains supply as a power supply and cannot use a direct current power supply for charging, the input range of a charging circuit which uses direct current as the power supply is limited in a small part, the output parameters of the charger cannot be adjusted according to the requirements of power supply voltage and battery voltage, and the battery can only be damaged by forced electrification.
SUMMERY OF THE UTILITY MODEL
To the phenomenon that traditional charging technology can't be adapting to the wide range automatically regulated of low pressure direct current, this application provides a lithium cell charging circuit, through detecting input direct current mains voltage and battery voltage simultaneously to adjust charging current based on the testing result, avoid the battery damage that mains voltage is too big or the battery continues to charge after being full of to lead to, it is safer.
The application provides a lithium battery charging circuit, including mains voltage detection module, control module, battery voltage detection module and the regulation module that charges, wherein:
one end of the power supply voltage detection module is connected with a power supply, and the other end of the power supply voltage detection module is connected with the control module and used for detecting the output voltage value of the power supply and transmitting the output voltage value to the control module;
one end of the battery voltage detection module is connected with a battery to be charged, and the other end of the battery voltage detection module is connected with the control module and used for detecting the current voltage value of the battery to be charged and transmitting the current voltage value to the control module;
the control module is connected with the charging adjusting module and used for controlling the charging adjusting module to start or stop charging based on the output voltage value of the power supply and controlling the charging adjusting module to adjust the charging current based on the current voltage value of the battery to be charged.
Several alternatives are provided below, but not as an additional limitation to the above general solution, but merely as a further addition or preference, each alternative being combinable individually for the above general solution or among several alternatives without technical or logical contradictions.
Optionally, the control module includes a microcontroller, the microcontroller includes a pulse width modulation output interface and two voltage analog conversion interfaces, the output ends of the power supply voltage detection module and the battery voltage detection module are respectively connected to a corresponding voltage analog conversion interface, the charging adjustment module is connected to the pulse width modulation output interface, and the control module controls the charging adjustment module by outputting a pulse width modulation signal.
Optionally, the charging adjustment module includes an NPN-type triode and a PNP-type triode, a collector of the NPN-type triode is connected to a base of the PNP-type triode, an emitter of the NPN-type triode is grounded, the base of the NPN-type triode is used as a control end of the charging adjustment module and is connected to the pulse width modulation output interface, the emitter of the PNP-type triode is connected to the power supply, and a collector of the PNP-type triode is connected to the battery to be charged.
Optionally, the lithium battery charging circuit further includes a protection module, where the protection module includes a clamping diode, one end of the clamping diode is connected to the pulse width modulation output interface, and the other end of the clamping diode is connected to the base of the NPN-type triode.
Optionally, the lithium battery charging circuit further comprises a current detection module, one end of the current detection module is connected with the negative electrode of the rechargeable battery for sampling, the other end of the current detection module is connected with the control end of the charging adjustment module, the current detection module is used for detecting the size of the charging current and feeding the size back to the charging adjustment module, and the charging adjustment module adjusts the charging current based on feedback.
Optionally, the current detection module includes a comparator and a current sampling resistor, one end of the current sampling resistor is connected to the battery to be charged, the other end of the current sampling resistor is connected to the inverting input terminal of the comparator, the input of the non-inverting input terminal of the comparator is a reference voltage, and the output terminal of the comparator is connected to the base of the NPN type triode.
Optionally, the reference voltage is provided by a reference module, the reference module includes a voltage reference source and a plurality of reference voltage sampling resistors connected in parallel at two ends of the voltage reference source and connected in series, and a reference voltage sampling point is arranged between one of the two adjacent reference voltage sampling resistors and serves as an output of the reference module.
Optionally, the power supply voltage detection module includes a plurality of power supply voltage sampling resistors connected in series, a power supply voltage sampling point is disposed between two adjacent power supply voltage sampling resistors, the power supply voltage sampling point is connected to the control module, one end of each of the plurality of power supply voltage sampling resistors connected in series is connected to the power supply, and the other end of each of the plurality of power supply voltage sampling resistors is grounded.
Optionally, the battery voltage detection module includes an operational amplifier and a plurality of battery voltage sampling resistors connected in series at two ends of the battery to be charged, wherein a battery voltage sampling point is arranged between two adjacent battery voltage sampling resistors, the non-inverting input terminal of the operational amplifier is connected to the battery voltage sampling point, the inverting input terminal of the operational amplifier is grounded, and the output terminal of the operational amplifier is connected to the control module.
Optionally, the lithium battery charging circuit further includes a power supply module, where the power supply module includes a current-limiting resistor connected to the power supply, a zener diode connected in series with the current-limiting resistor, and an electrolytic capacitor connected in parallel with the zener diode.
This application lithium battery charging circuit detects through supply voltage and battery voltage simultaneously to adjust charging current based on the testing result, avoid the battery damage that supply voltage is too big or the battery continues to charge after being full of, it is safer.
Drawings
Fig. 1 is a schematic block diagram of a lithium battery charging circuit according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a lithium battery charging circuit according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, fig. 1 provides a lithium battery charging circuit.
An embodiment of the present application provides a lithium battery charging circuit, lithium battery charging circuit includes mains voltage detection module, control module, battery voltage detection module and the regulation module that charges, wherein:
one end of the power supply voltage detection module is connected with the power supply, and the other end of the power supply voltage detection module is connected with the control module and used for detecting the output voltage value of the power supply and transmitting the output voltage value to the control module;
one end of the battery voltage detection module is connected with the battery to be charged, and the other end of the battery voltage detection module is connected with the control module and used for detecting the current voltage value of the battery to be charged and transmitting the current voltage value to the control module;
the control module is connected with the charging regulation module and used for controlling the charging regulation module to start or stop charging based on the output voltage value of the power supply and the voltage value of the battery and controlling the charging regulation module to regulate charging current based on the current voltage value of the battery to be charged.
It can be understood that when the output voltage value of the power supply is detected to be within the preset normal range and the current voltage value of the battery to be charged does not exceed the charging limit voltage, the control module controls the charging adjustment module to perform normal charging; and when the output voltage value of the power supply is detected to exceed a preset normal range or the current voltage value of the battery to be charged exceeds the charging limit voltage, controlling the charging regulation module to stop charging so as to prevent the battery from being damaged.
Above-mentioned lithium battery charging circuit detects through supply voltage and battery voltage simultaneously to adjust charging current based on the testing result, avoid supply voltage too big or battery to be full of the back and continue to charge the battery damage that leads to, it is safer.
Referring to fig. 2, fig. 2 is a schematic circuit diagram of a lithium battery charging circuit according to an embodiment of the present invention.
In another embodiment, the control module comprises a microcontroller, the microcontroller comprises a pulse width modulation output interface and two voltage analog conversion interfaces, the output ends of the power supply voltage detection module and the battery voltage detection module are respectively connected to a corresponding one of the voltage analog conversion interfaces, the charging regulation module is connected to the pulse width modulation output interface, and the control module controls the charging regulation module by outputting a pulse width modulation signal.
The pulse width modulation is an analog control mode, and the bias of a transistor base electrode or an MOS tube grid electrode is modulated according to the change of corresponding load to change the conduction time of the transistor or the MOS tube, so that the change of the output of the switching voltage-stabilized power supply is realized. This way the output voltage of the power supply can be kept constant when the operating conditions change, which is a very effective technique for controlling an analog circuit by means of the digital signal of the microprocessor. Pulse width modulation techniques are widely used in many areas ranging from measurement, communications to power control and conversion. This lithium battery charging circuit passes through control module output pulse width modulation signal control regulation module that charges, is convenient for adjust charging current and set for normal charging voltage scope to satisfy the needs of charging to different batteries.
Illustratively, the microcontroller is a single chip microcomputer a1, and includes eight pins, in addition to AN analog-to-digital conversion pin AN0 (i.e., one of the voltage analog conversion interfaces), AN analog-to-digital conversion pin AN1 (i.e., the other voltage analog conversion interface), and a pwm output pin P1A (i.e., a pwm output interface), the microcontroller further includes: a common connection pin VSS, a power supply pin VDD, an external frequency input pin OSC1, an external frequency input pin OSC2, and a reset pin MCLR.
Wherein: the common connection pin VSS is grounded; the power supply pin VDD is connected to a power supply for supplying power to the singlechip A1, and the power supply pin VDD is also grounded through a filter capacitor C3; a crystal oscillator X1 is connected between the external frequency input pin OSC1 and the external frequency input pin OSC2, one output pin of the crystal oscillator X1 is grounded through a fourth capacitor C4, and the other output pin is grounded through a sixth capacitor C6; and a sixteenth resistor R16 and a seventeenth resistor R17 which are connected in series are connected between the reset pin/MCLR and a power supply for supplying power to the singlechip A1, and the sixteenth resistor R16 and the seventeenth resistor R17 are grounded through a seventh capacitor C7.
In another embodiment, the lithium battery charging circuit further comprises a power supply module for supplying power to the microcontroller singlechip A1, and the singlechip A1 starts to work after being powered on. The power supply module comprises a current-limiting resistor connected with a power supply, a voltage stabilizing diode connected with the current-limiting resistor in series, and an electrolytic capacitor connected with the voltage stabilizing diode in parallel.
Illustratively, the current limiting resistor comprises a third resistor R3 and a fourth resistor R4, the zener diode is a second zener diode Z2, and the electrolytic capacitor is a first electrolytic capacitor E1.
The third resistor R3 is connected with the fourth resistor R4 in parallel, one end of the parallel connection is connected with a power supply, the other end of the parallel connection is used as a power supply output end (+5.1V) to supply power to the single chip microcomputer A1, for stable output, the power supply output end is grounded through a second zener diode Z2 which is reversely connected, namely the power supply output end is connected with the negative electrode of the second zener diode Z2, the positive electrode of the second zener diode Z2 is grounded, and the second zener diode Z2 is further connected with the first electrolytic capacitor E1 in parallel.
In another embodiment, the charging adjustment module comprises an NPN-type triode and a PNP-type triode, a collector of the NPN-type triode is connected to a base of the PNP-type triode, an emitter of the NPN-type triode is grounded, a base of the NPN-type triode is used as a control terminal of the charging adjustment module and is connected to the pulse width modulation output interface, an emitter of the PNP-type triode is connected to the power supply, and a collector of the PNP-type triode is connected to the battery to be charged.
Illustratively, the PNP transistor is a first transistor Q1 and the NPN transistor is a second transistor Q2. The first triode Q1 and the second triode Q2 are used as switching devices, wherein the first triode Q is connected between a power supply and a battery to be charged, the conducting state of the first triode Q1 is controlled by the second triode Q2, the control module directly controls the second triode Q2 through the pulse width modulation output interface, and then indirectly controls the first triode Q1.
For further refinement and optimization, the charge regulation module further includes peripheral auxiliary elements, such as a first zener diode Z1, a first diode D1, a second diode D2, a third diode D3, a fifth diode D5, a first capacitor C1, a first resistor R1, a seventh resistor R7, and an eleventh resistor R11.
Wherein the first capacitor C1 and the first resistor R1 are connected in series between the emitter and the collector of the first transistor Q1. A cathode of the first diode D1 is connected to an emitter of the first transistor Q1, and an anode of the first diode D1 is connected to a collector of the first transistor Q1. The cathode of the second diode D2 is connected to the collector of the first transistor Q1, and the anode of the second diode D2 is grounded. The cathode of the third diode D3 is connected to the emitter of the first transistor Q1, and the anode is connected to the power supply. Two ends of the seventh resistor R7 are respectively connected with the base electrode and the emitter electrode of the first triode Q1. The collector of the second triode Q2 is connected with the base of the first triode Q1 through a first zener diode Z1 and an eleventh resistor R11 in sequence, and the anode of the first zener diode Z1 is connected with the collector of the second triode Q2. The fifth diode D5 is a clamp diode, and the emitter of the second transistor Q2 is grounded via the fifth diode D5. The base of the second triode Q2 is connected to the pulse width modulation output pin P1A of the singlechip A1, and the collector of the first triode Q1 is connected with the battery to be charged. In addition, the collector of the first triode Q1 is connected to the anode of the rechargeable battery through an inductor L1.
In another embodiment, the lithium battery charging circuit further comprises a protection module, the protection module is arranged between the control module and the charging regulation module, the protection module comprises a clamping diode, one end of the clamping diode is connected with the pulse width modulation output interface, and the other end of the clamping diode is connected with the base electrode of the NPN-type triode. The protection module plays a role in clamping and protecting the pulse width modulation signal output by the microcontroller.
Illustratively, the clamping diode in the protection module is a fourth diode D4. In order to stabilize the signal output of the pwm output interface, the protection module further includes a filter capacitor and other peripheral components, and specifically includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10 and a second capacitor C2, the pwm output pin P1A of the single chip microcomputer a1 is sequentially connected to the fourth diode D4 through the tenth resistor R10 and the eighth resistor R8, the tenth resistor R10 and the eighth resistor R8 are grounded through the second capacitor C2, and the ninth resistor R9 is connected in parallel to two ends of the second capacitor C2.
In another embodiment, the lithium battery charging circuit further comprises a current detection module, one end of the current detection module is connected with the negative electrode of the battery to be charged for sampling, the other end of the current detection module is connected with the control end of the charging adjustment module, the current detection module is used for detecting the magnitude of the charging current and feeding the magnitude back to the charging adjustment module, and the charging adjustment module adjusts the charging current based on the feedback.
Specifically, the current detection module comprises a comparator and a current sampling resistor, one end of the current sampling resistor is connected with a battery to be charged, the other end of the current sampling resistor is connected with the inverting input end of the comparator, the input of the non-inverting input end of the comparator is reference voltage, and the output end of the comparator is connected with the base electrode of the NPN-type triode. In this embodiment, the current sampling resistor samples the charging current, converts the charging current into a voltage, inputs the voltage to the comparator, compares the voltage with a reference voltage, and controls the charging adjustment module to adjust the charging current based on the comparison result.
Illustratively, the comparator is a first operational amplifier U1, and the current sampling resistors include a twenty-third resistor R23 and a twenty-fourth resistor R24. The first operational amplifier U1 may be configured with a power supply alone or also be powered by the aforementioned power supply module.
The current detection module may further include peripheral elements such as a thirteenth resistor R13, a fourteenth resistor R14, a twenty-second resistor R22, and a fifth capacitor C5. The two ends of a thirteenth resistor R13 are respectively connected to the inverting input end and the output end of the first operational amplifier U1, a fourteenth resistor R14 is connected between the output end of the first operational amplifier U1 and the base of the second triode Q2, a twenty-third resistor R23 is connected between the negative electrode of the battery to be charged and the inverting input end of the first operational amplifier U1, one end of a twenty-fourth resistor R24 is connected with the negative electrode of the battery to be charged, the other end of the twenty-fourth resistor R24 is grounded, one end of a twenty-second resistor R22 is connected with a reference voltage, the other end of the twenty-second resistor R22 is connected with the non-inverting input end of the first operational amplifier U1, one end of a fifth capacitor C5 is connected with the.
In operation, the twenty-third resistor R23 samples the charging current to form a charging voltage on the twenty-fourth resistor R24, and transmits the charging voltage to the first operational amplifier U1 for comparison with the reference voltage, and the first operational amplifier U1 controls the charging adjustment module to adjust the charging current based on the comparison result.
The base of the second transistor Q2 in the charging adjustment module is connected to the fourteenth resistor R14 in the current detection module and the fourth diode D4 in the protection module at the same time, and is controlled by the current detection module and the control module at the same time, and is configured to receive the pulse signal of the control module and the signal output by the first operational amplifier U1 and adjust the charging current accordingly. The control module controls the conduction and the disconnection of the second triode Q2 through a pulse signal output by the protection module, the signal output by the first operational amplifier U1 controls the conduction amplitude of the second triode Q2, the conduction and the disconnection of the second triode Q2 control the conduction and the disconnection of the first triode Q1, and the conduction amplitude of the second triode Q2 controls the conduction amplitude of the first triode Q1, so that whether the battery to be charged is charged and the magnitude of the charging current is controlled.
In another embodiment, the reference voltage is provided by a reference module, the reference module comprises a voltage reference source and a plurality of reference voltage sampling resistors connected in series with each other in parallel at two ends of the voltage reference source, and a reference voltage sampling point is arranged between two adjacent reference voltage sampling resistors as the output of the reference module.
Illustratively, the reference voltage sampling resistor comprises an eighteenth resistor R18 and a twenty-first resistor R21, the reference module further comprises a current limiting resistor, a fifth resistor R5 and a sixth resistor R6, and a second electrolytic capacitor E2.
The voltage reference source Z3 may be a zener diode or a TL431 chip, wherein the TL431 chip may obtain a voltage output with better precision and stability, and hereinafter, the TL431 chip is taken as an example of a specific connection mode of the voltage reference source Z3 and other elements; the fifth resistor R5 and the sixth resistor R6 are mutually connected in parallel, one end of the parallel connection is connected with a power supply, the other end of the parallel connection is connected with the cathode and the reference electrode of the voltage reference source Z3, the cathode and the reference electrode of the voltage reference source Z3 are also grounded through the second electrolytic capacitor E2, and the anode of the voltage reference source Z3 is grounded; the eighteenth resistor R18 and the twenty-first resistor R21 are connected in series and in parallel with the third zener diode Z3, a reference voltage sampling point is arranged between the eighteenth resistor R18 and the twenty-first resistor R21, the reference voltage sampling point is connected with the twenty-second resistor R22 in the current detection module, and the reference voltage is transmitted to the first operational amplifier U1.
In another embodiment, the battery voltage detection module includes an operational amplifier and a plurality of battery voltage sampling resistors connected in series with each other and connected to two ends of the battery to be charged, wherein a battery voltage sampling point is disposed between two adjacent battery voltage sampling resistors, a non-inverting input terminal of the operational amplifier is connected to the battery voltage sampling point, an inverting input terminal of the operational amplifier is grounded, and an output terminal of the operational amplifier is connected to the control module.
Illustratively, the operational amplifier is a second operational amplifier U2, and the battery voltage sampling resistor is a twenty-fifth resistor R25 and a twenty-sixth resistor R26.
The twenty-fifth resistor R25 and the twenty-sixth resistor R26 are connected to two ends of the battery and used for sampling battery voltage, a battery voltage sampling point is arranged between the twenty-fifth resistor R25 and the twenty-sixth resistor R26 and is connected with the non-inverting input end of the second operational amplifier U2 through the twentieth resistor R20, the sampled battery voltage is input into the second operational amplifier U2, the output end of the second operational amplifier U2 is connected to a voltage analog conversion pin AN1 of the singlechip A1, and the amplified battery sampling voltage is input into the singlechip A1.
The battery voltage detection module further comprises a matching resistor twelfth resistor R12 and a fifteenth resistor R15 of the second operational amplifier U2 for adjusting the amplification factor of the second operational amplifier U2. The twelfth resistor R12 and the fifteenth resistor R15 are connected in series, the inverting input end of the second operational amplifier U2 is connected between the twelfth resistor R12 and the fifteenth resistor R15, the other end of the fifteenth resistor R15 is grounded, and the other end of the twelfth resistor R12 is connected with the output end of the second operational amplifier U2. The second operational amplifier U2 may also be powered by the aforementioned power supply module.
In another embodiment, the power voltage detection module includes a plurality of power voltage sampling resistors connected in series, wherein a power voltage sampling point is disposed between two adjacent power voltage sampling resistors, the power voltage sampling point is connected to the control module, and one end of each of the plurality of power voltage sampling resistors connected in series is connected to the power supply, and the other end is grounded.
Illustratively, the power supply voltage sampling resistor comprises a second resistor R2 and a nineteenth resistor R19 which are connected in series between a power supply and the ground, a power supply voltage sampling point is arranged between the second resistor R2 and the nineteenth resistor R19 and is used for sampling the output voltage of the power supply, and the power supply voltage sampling point is connected to a voltage analog conversion pin AN0 of the singlechip A1 and is used for inputting the power supply sampling voltage into the singlechip A1.
In this embodiment, the working process of the lithium battery charging circuit is as follows: the singlechip A1 begins work after getting electricity through the power supply module, detects whether the output voltage value of power is in the normal scope that singlechip A1 predetermines through supply voltage detection module earlier:
if the output voltage value of the power supply exceeds the preset normal range, the pulse width modulation output pin P1A is set to be at a low level, the second triode Q2 in the charging adjusting module is not conducted, the base voltage of the first triode Q1 is high, the first triode Q1 is cut off, and charging is stopped.
And if the output voltage value of the power supply is within a preset normal range, controlling the charging regulation module to start charging. The detection by the battery voltage detection module in the charging process can specifically include three conditions:
1. before the voltage of the battery to be charged does not reach the charging limit voltage set by the singlechip A1, the pulse width modulation output pin P1A of the singlechip A1 in the control module is set to be at a high level, the second triode Q2 in the charging regulation module is conducted, the current detection module controls the conduction amplitude of the second triode Q2 in the charging regulation module based on two signals of the reference voltage generated by the reference module and the sampled charging voltage, and further controls the conduction amplitude of the first triode Q1, so that the charging current is stabilized at the set maximum value to carry out constant current charging.
2. When the voltage of the battery to be charged reaches the charging limit voltage, the output duty ratio of a pulse width modulation output pin P1A of a singlechip A1 in the control module is gradually reduced from 100% to 0%, so that the voltage of the battery is stabilized at the set charging limit voltage, and when the duty ratio is less than or equal to 5%, the pulse width modulation output pin P1A can be set to a low level to stop charging.
3. When the voltage of the battery to be charged is lower than the set lowest voltage, the output duty ratio of a pin P1A of a singlechip A1 in the control module is set to be 10 percent, the protection module controls the charging adjustment module to charge the battery with low current pulses, and the battery is normally charged when the voltage of the battery is higher than the set lowest voltage; and stopping charging if the battery voltage cannot be recovered to be higher than the set minimum voltage.
The charging is carried out aiming at the batteries with different voltage grades, and only the threshold values such as the charging limiting voltage of the control module are required to be changed.
The lithium battery charging circuit of each embodiment detects the power supply voltage and the battery voltage simultaneously, adjusts the charging current based on the detection result, avoids the damage of the battery caused by continuous charging after the power supply voltage is too large or the battery is fully charged, and is safer. Meanwhile, the charging voltage range is wide, the charging limiting voltage in the constant-voltage charging stage is adjustable, the maximum charging current in the constant-current charging stage is adjustable, and the charging requirements of batteries with different voltage grades can be met; when the battery pack is in an undervoltage state, a narrow pulse type low-current charging mode is adopted to recover the voltage of the battery to a normal voltage and then perform constant-current and constant-voltage charging, so that the service life of the battery pack is not influenced by long-time standing.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features. When technical features in different embodiments are represented in the same drawing, it can be seen that the drawing also discloses a combination of the embodiments concerned.
The above examples only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application.
Claims (10)
1. Lithium battery charging circuit, its characterized in that, including mains voltage detection module, control module, battery voltage detection module and the regulation module that charges, wherein:
one end of the power supply voltage detection module is connected with a power supply, and the other end of the power supply voltage detection module is connected with the control module and used for detecting the output voltage value of the power supply and transmitting the output voltage value to the control module;
one end of the battery voltage detection module is connected with a battery to be charged, and the other end of the battery voltage detection module is connected with the control module and used for detecting the current voltage value of the battery to be charged and transmitting the current voltage value to the control module;
the control module is connected with the charging adjusting module and used for controlling the charging adjusting module to start or stop charging based on the output voltage value of the power supply and controlling the charging adjusting module to adjust the charging current based on the current voltage value of the battery to be charged.
2. The lithium battery charging circuit according to claim 1, wherein the control module comprises a microcontroller, the microcontroller comprises a pwm output interface and two voltage analog conversion interfaces, the output terminals of the power supply voltage detection module and the battery voltage detection module are respectively connected to a corresponding one of the voltage analog conversion interfaces, the charging regulation module is connected to the pwm output interface, and the control module controls the charging regulation module by outputting a pwm signal.
3. The lithium battery charging circuit according to claim 2, wherein the charging adjustment module comprises an NPN-type transistor and a PNP-type transistor, a collector of the NPN-type transistor is connected to a base of the PNP-type transistor, an emitter of the NPN-type transistor is grounded, a base of the NPN-type transistor serves as a control terminal of the charging adjustment module and is connected to the pwm output interface, an emitter of the PNP-type transistor is connected to the power supply, and a collector of the PNP-type transistor is connected to the battery to be charged.
4. The lithium battery charging circuit of claim 3, further comprising a protection module comprising a clamping diode, wherein one end of the clamping diode is connected to the pulse width modulation output interface and the other end of the clamping diode is connected to the base of the NPN transistor.
5. The lithium battery charging circuit of claim 3, further comprising a current detection module, wherein one end of the current detection module is connected to the negative electrode of the battery to be charged for sampling, the other end of the current detection module is connected to the control terminal of the charging adjustment module, the current detection module is configured to detect the magnitude of the charging current and feed the magnitude back to the charging adjustment module, and the charging adjustment module adjusts the charging current based on the feedback.
6. The lithium battery charging circuit according to claim 5, wherein the current detection module comprises a comparator and a current sampling resistor, one end of the current sampling resistor is connected to the battery to be charged, the other end of the current sampling resistor is connected to the inverting input terminal of the comparator, the non-inverting input terminal of the comparator has an input of a reference voltage, and the output terminal of the comparator is connected to the base of the NPN-type triode.
7. The lithium battery charging circuit according to claim 6, wherein the reference voltage is provided by a reference module, the reference module comprises a voltage reference source and a plurality of reference voltage sampling resistors connected in series with each other in parallel at two ends of the voltage reference source, and a reference voltage sampling point is provided between two adjacent reference voltage sampling resistors as an output of the reference module.
8. The lithium battery charging circuit of claim 1, wherein the power supply voltage detection module comprises a plurality of power supply voltage sampling resistors connected in series, a power supply voltage sampling point is provided between two adjacent power supply voltage sampling resistors, the power supply voltage sampling point is connected to the control module, and one end of each of the plurality of power supply voltage sampling resistors connected in series is connected to the power supply and the other end is grounded.
9. The lithium battery charging circuit according to claim 1, wherein the battery voltage detection module comprises an operational amplifier and a plurality of battery voltage sampling resistors connected in series at two ends of the battery to be charged, wherein a battery voltage sampling point is arranged between two adjacent battery voltage sampling resistors, a non-inverting input terminal of the operational amplifier is connected to the battery voltage sampling point, an inverting input terminal of the operational amplifier is grounded, and an output terminal of the operational amplifier is connected to the control module.
10. The lithium battery charging circuit of claim 1, further comprising a power supply module comprising a current limiting resistor coupled to the power source, a zener diode coupled in series with the current limiting resistor, and an electrolytic capacitor coupled in parallel with the zener diode.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020282686.9U CN211958802U (en) | 2020-03-06 | 2020-03-06 | Lithium battery charging circuit |
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| CN202020282686.9U CN211958802U (en) | 2020-03-06 | 2020-03-06 | Lithium battery charging circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113489114A (en) * | 2021-08-03 | 2021-10-08 | 广东友电新能源科技有限公司 | Charging control circuit, charging control method and charging device |
| CN113806269A (en) * | 2021-09-14 | 2021-12-17 | 深圳群芯微电子有限责任公司 | USB port constant voltage power supply circuit |
-
2020
- 2020-03-06 CN CN202020282686.9U patent/CN211958802U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113489114A (en) * | 2021-08-03 | 2021-10-08 | 广东友电新能源科技有限公司 | Charging control circuit, charging control method and charging device |
| CN113806269A (en) * | 2021-09-14 | 2021-12-17 | 深圳群芯微电子有限责任公司 | USB port constant voltage power supply circuit |
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