Charging circuit for improving charging efficiency of lithium battery

Abstract

The utility model discloses a charging circuit capable of improving the charging efficiency of a lithium battery. The circuit is composed of a voltage regulation circuit and a charging and discharging chip U1, the voltage regulation circuit is composed of a potentiometer R9, a sixth divider resistor R12, a fifth divider resistor R15, a fourth divider resistor R16, a first divider resistor R17, a second divider resistor R18, a third resistor R22 and an NMOS tube Q6, and one pin of the charging and discharging chip U1 is connected with one pin of the first divider resistor R17. According to the utility model, the charging voltage at the constant current stage can be properly improved, so that the battery rapidly reaches the constant voltage stage, and the charging efficiency of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the field of charging protection, and more specifically, to a charging circuit for improving the charging efficiency of lithium batteries. Background Art

[0002] With the improvement of lithium battery charging technology, higher requirements are put forward for the stability, charging time and charging performance of the charging circuit. According to the characteristics of lithium batteries, the charging of lithium batteries is divided into a trickle stage, a constant current stage and a constant voltage stage. When the constant current charging reaches the battery voltage, the charging current needs to be continuously reduced until the lithium battery is fully charged in the constant voltage stage. The fixed charging voltage in the charging circuit will greatly affect the charging time and reduce the charging efficiency. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is to overcome the deficiencies in the prior art and provide a charging circuit for improving the charging efficiency of lithium batteries.

[0004] A charging circuit for improving the charging efficiency of lithium batteries according to the utility model is realized through the following technical solutions. The circuit consists of a voltage adjustment circuit and a charge-discharge chip U1. A potentiometer R9, a sixth voltage-dividing resistor R12, a fifth voltage-dividing resistor R15, a fourth voltage-dividing resistor R16, a first voltage-dividing resistor R17, a second voltage-dividing resistor R18, a third resistor R22, and an NMOS transistor Q6 form the voltage adjustment circuit;

[0005] One pin of the 12th pin of the charge-discharge chip U1 of the voltage adjustment circuit is connected to one pin of the first voltage-dividing resistor R17. The other pin of the first voltage-dividing resistor R17 is connected to one pin of the second voltage-dividing resistor R18. The other pin of the second voltage-dividing resistor R18 is connected to the drain of the NMOS transistor Q6. The gate of the NMOS transistor Q6 is controlled by a single-chip microcomputer U3, and the control signal is switch. The gate of the NMOS transistor Q6 is connected to one pin of the third resistor R22. The other pin of the third resistor R22 is connected to the source of the NMOS transistor Q6 and grounded. The 12th pin of the charge-discharge chip U1 is simultaneously connected to one pin of the fourth voltage-dividing resistor R16 and the fifth voltage-dividing resistor R15. The other pin of the fourth voltage-dividing resistor R16 is grounded. The other pin of the fifth voltage-dividing resistor R15 is connected to one pin of the sixth voltage-dividing resistor R12. The other pin of the sixth voltage-dividing resistor R12 is connected to one pin of the potentiometer R9. The other pin of the potentiometer R9 is connected to the output voltage terminal Vo.

[0006] The switching transistor Q6 is an N-channel field effect transistor.

[0007] The potentiometer R9 is a variable resistor; the sixth voltage-dividing resistor R12 is a thick-film resistor; the fifth voltage-dividing resistor R15 is a thick-film resistor; the fourth voltage-dividing resistor R16 is a thick-film resistor; the first voltage-dividing resistor R17 is a thick-film resistor; the second voltage-dividing resistor R18 is a thick-film resistor; the third voltage-dividing resistor R22 is a thick-film resistor;

[0008] The model of the single-chip microcomputer U3 is FM33LC023U.

[0009] The charging and discharging chip U1 is BQ24610.

[0010] Compared with the prior art, the beneficial effects of the present utility model are:

[0011] The single-chip microcomputer serves as the control switch signal terminal. During the conduction stage of the NMOS transistor Q6, constant-current charging control is performed. Since the value of Vo is higher than the charging voltage of the battery at this time, when the charging current remains unchanged, the charging efficiency can be improved more compared to when Vo is a fixed value. When the NMOS transistor is not conducting, the constant-voltage charging stage is carried out. During this charging process, due to the dynamic adjustment of the charging voltage, while improving the charging efficiency, the battery is not damaged.

[0012] Compared with the prior art, the present utility model can appropriately increase the charging voltage during the constant-current stage, enabling the battery to quickly reach the constant-voltage stage and improving the charging efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is the circuit diagram of the present utility model;

[0014] Figure 2 is the principle block diagram of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] In order to more clearly understand the above-mentioned objects, features, and advantages of the present utility model, the present utility model will be described in detail below with reference to the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present utility model. The described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present utility model. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art belonging to the technical field of the present utility model. The terms used in the specification of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model.

[0016] Please refer to Figures 1 to 2 . It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present utility model are shown in the figure, rather than the actual quantity and accurate circuit. The actual configuration can change the quantity and layout of components according to the charging and discharging requirements, and its actual layout may also be more complex due to different requirements.

[0017] A charging circuit for improving the charging efficiency of a lithium battery consists of a voltage adjustment circuit and a charge-discharge chip U1. A potentiometer R9, a sixth voltage-dividing resistor R12, a fifth voltage-dividing resistor R15, a fourth voltage-dividing resistor R16, a first voltage-dividing resistor R17, a second voltage-dividing resistor R18, a third resistor R22, and an NMOS transistor Q6 form the voltage adjustment circuit;

[0018] One pin of the first voltage-dividing resistor R17 is connected to pin 12 of the charge-discharge chip U1 in the voltage adjustment circuit. The other pin of the first voltage-dividing resistor R17 is connected to one pin of the second voltage-dividing resistor R18. The other pin of the second voltage-dividing resistor R18 is connected to the drain of the NMOS transistor Q6. The gate of the NMOS transistor Q6 is controlled by a single-chip microcomputer U3, and the control signal is switch. The gate of the NMOS transistor Q6 is connected to one pin of the third resistor R22. The other pin of the third resistor R22 is connected to the source of the NMOS transistor Q6 and grounded. Pin 12 of the charge-discharge chip U1 is simultaneously connected to one pin of the fourth voltage-dividing resistor R16 and the fifth voltage-dividing resistor R15. The other pin of the fourth voltage-dividing resistor R16 is grounded. The other pin of the fifth voltage-dividing resistor R15 is connected to one pin of the sixth voltage-dividing resistor R12. The other pin of the sixth voltage-dividing resistor R12 is connected to one pin of the potentiometer R9. The other pin of the potentiometer R9 is connected to the output voltage terminal Vo.

[0019] After the NMOS is turned on in the voltage adjustment circuit, after the first voltage-dividing resistor R17, the second voltage-dividing resistor R18, and the fourth voltage-dividing resistor R16 are connected in parallel, since the FB voltage value remains unchanged, it is inversely deduced that the Vo voltage increases after being divided by the potentiometer R9, the sixth voltage-dividing resistor R12, and the fifth voltage-dividing resistor R15.

[0020] When switch is at a high level, the NMOS transistor Q6 is turned on, and the first voltage-dividing resistor R17, the second voltage-dividing resistor R18, and the fourth voltage-dividing resistor R16 are connected in parallel. Since the FB signal voltage remains unchanged, Vo increases.

[0021] During the on - stage of the NMOS, the single - chip microcomputer outputs a constant - current value. Since the charging voltage is higher than the battery charging voltage at this time, the battery can quickly reach the constant - voltage stage, improving the charging efficiency. After reaching the constant - voltage stage, the switch becomes low - level, and the NMOS transistor Q6 is not conducting. The fourth voltage - dividing resistor R16, the potentiometer R9, the sixth voltage - dividing resistor R12, and the fifth voltage - dividing resistor R15 are used for voltage division, and the value of Vo decreases. At this time, the single - chip microcomputer conducts charging in the constant - voltage stage, reducing the charging current until the battery is fully charged.

[0022] The switching transistor Q6 is an N - channel field - effect transistor.

[0023] The potentiometer R9 is an adjustable resistor; the sixth voltage - dividing resistor R12 is a thick - film resistor; the fifth voltage - dividing resistor R15 is a thick - film resistor; the fourth voltage - dividing resistor R16 is a thick - film resistor; the first voltage - dividing resistor R17 is a thick - film resistor; the second voltage - dividing resistor R18 is a thick - film resistor; the third voltage - dividing resistor R22 is a thick - film resistor;

[0024] The model of the single - chip microcomputer U3 is FM33LC023U.

[0025] The charge - discharge chip U1 is BQ24610.

[0026] The above - mentioned is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A charging circuit for improving the charging efficiency of a lithium battery, characterized in that, The circuit consists of a voltage regulation circuit and a charge and discharge chip U1. The voltage regulation circuit is composed of a potentiometer R9, a sixth voltage-dividing resistor R12, a fifth voltage-dividing resistor R15, a fourth voltage-dividing resistor R16, a first voltage-dividing resistor R17, a second voltage-dividing resistor R18, a third resistor R22, and a switching transistor NMOS transistor Q6. For the voltage regulation circuit, the 12th pin of the charge and discharge chip U1 is connected to one pin of the first voltage-dividing resistor R17. The other pin of the first voltage-dividing resistor R17 is connected to one pin of the second voltage-dividing resistor R18. The other pin of the second voltage-dividing resistor R18 is connected to the drain of the NMOS transistor Q6. The gate of the NMOS transistor Q6 is controlled by the microcontroller U3, and the control signal is switch. The gate of the NMOS transistor Q6 is connected to one pin of the third resistor R22. The other pin of the third resistor R22 is connected to the source of the NMOS transistor Q6 and grounded. The 12th pin of the charge and discharge chip U1 is simultaneously connected to one pin of the fourth voltage-dividing resistor R16 and the fifth voltage-dividing resistor R15. The other pin of the fourth voltage-dividing resistor R16 is grounded. The other pin of the fifth voltage-dividing resistor R15 is connected to one pin of the sixth voltage-dividing resistor R12. The other pin of the sixth voltage-dividing resistor R12 is connected to one pin of the potentiometer R9. The other pin of the potentiometer R9 is connected to the output voltage terminal Vo.

2. The charging circuit for improving the charging efficiency of a lithium battery according to claim 1, characterized in that, The switching transistor NMOS Q6 is an N-channel field effect transistor.

3. The charging circuit for improving the charging efficiency of a lithium battery according to claim 1, characterized in that, The potentiometer R9 is an adjustable resistor; the sixth voltage-dividing resistor R12 is a thick film resistor; the fifth voltage-dividing resistor R15 is a thick film resistor; the fourth voltage-dividing resistor R16 is a thick film resistor; the first voltage-dividing resistor R17 is a thick film resistor; the second voltage-dividing resistor R18 is a thick film resistor; the third voltage-dividing resistor R22 is a thick film resistor.

4. The charging circuit for improving the charging efficiency of a lithium battery according to claim 1, characterized in that, The model of the microcontroller U3 is FM33LC023U.

5. The charging circuit for improving the charging efficiency of a lithium battery according to claim 1, characterized in that, The model of the charge and discharge chip U1 is BQ24610.

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