Anti-backflow lithium battery charging circuit and equipment

Abstract

The utility model discloses an anti-backflow lithium battery charging circuit and equipment. The circuit comprises a charging module and an anti-backflow module, the anti-backflow module comprises a monitoring chip U1, an MOS tube Q2, an MOS tube Q3 and a diode D2; the input end of the monitoring chip U1 is used for being connected with a power supply, the output end of the monitoring chip U1 is connected with the grid electrode of the MOS tube Q2, the source electrode of the MOS tube Q2 is grounded, the drain electrode of the MOS tube Q2 is connected with the grid electrode of the MOS tube Q3, the drain electrode of the MOS tube Q3 is connected with the anode of the diode D2 and the charging module, and the source electrode of the MOS tube Q3 is connected with the cathode of the diode D2 and the battery; the anti-backflow module generates high and low level signals at the output end of the monitoring chip U1 according to the connection condition of the power supply so as to control the MOS transistor Q2 and the MOS transistor Q3 to be switched on or switched off at the same time. According to the anti-backflow lithium battery charging circuit, the charging efficiency can be improved during charging, the reverse current can be effectively blocked when charging is stopped, and meanwhile the anti-backflow lithium battery charging circuit has the advantages of being simple in circuit structure, low in cost and the like.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a backflow prevention lithium battery charging circuit and device. Background Technology

[0002] Lithium-ion batteries are widely used in consumer electronics, energy storage systems, and electric vehicles due to their high energy density and long cycle life. Generally, lithium-ion batteries are sensitive to charging and discharging conditions; therefore, backflow prevention circuits (preventing battery current from flowing back into the charger or external circuitry) are a critical design requirement for lithium-ion battery charging circuits.

[0003] Existing technologies generally use Schottky diodes to prevent reverse current flow. Since any diode has internal resistance, there will inevitably be a voltage drop, which will reduce the charging efficiency and increase the product temperature due to the heat generated. Therefore, the charging efficiency is generally low. Utility Model Content

[0004] The purpose of this application is to provide an anti-backflow lithium battery charging circuit and device to solve the technical problem of low charging efficiency in existing charging circuits. The various technical effects of the preferred technical solutions provided in this application are detailed below.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] In a first aspect, this application provides an anti-backflow lithium battery charging circuit, comprising a charging module and an anti-backflow module; the charging module is used to connect to a power source, and the anti-backflow module is used to connect to a battery; the anti-backflow module includes a monitoring chip U1, a MOSFET Q2, a MOSFET Q3, and a diode D2; the input terminal VIN of the monitoring chip U1 is connected to the power source, the output terminal VOUT of the monitoring chip U1 is connected to the gate of the MOSFET Q2, the source of the MOSFET Q2 is grounded, the drain of the MOSFET Q2 is connected to the gate of the MOSFET Q3, the drain of the MOSFET Q3 is connected to the anode of the diode D2 and the charging module, and the source of the MOSFET Q3 is connected to the cathode of the diode D2 and the battery; the anti-backflow module generates high and low level signals at the output terminal VOUT of the monitoring chip U1 according to the connection status of the power source, to control the simultaneous conduction or cutoff of the MOSFETs Q2 and Q3.

[0007] In some embodiments, the anti-backflow module further includes resistors R1, R2, R3, and R4, capacitors C5 and C6; one end of resistor R1 is connected to both the power supply and the charging module, the other end of resistor R1 is connected to both the input terminal VIN of the monitoring chip U1 and one end of resistor R2, and the other end of resistor R2 is connected to and grounded to the ground terminal of the monitoring chip U1; one end of resistor R3 is connected to the drain of MOSFET Q2, the other end of resistor R3 is connected to both the gate of MOSFET Q3 and one end of resistor R4, the other end of resistor R4 is connected to both the source of MOSFET Q3, the cathode of diode D2, one end of capacitor C6, and the battery, wherein one end of capacitor C6 is grounded; one end of capacitor C5 is connected to both the drain of MOSFET Q3, the anode of diode D2, and the charging module, and the other end of capacitor C5 is grounded.

[0008] In some embodiments, the charging module includes a charging chip U2 and a driving transistor Q1; the driving pin of the charging chip U2 is connected to the gate of the driving transistor Q1, the driving voltage pin of the charging chip U2 is connected to the power supply, the other end of the resistor R1 and the source of the driving transistor Q1, and the drain of the driving transistor Q1 is connected to the drain of the MOS transistor Q3 and the anode of the diode D2.

[0009] In some embodiments, the charging module includes an inductor L1 and a resistor R5; the negative detection pin of the charging chip U2 is connected to one end of the resistor R5, one end of the capacitor C5, the drain of the MOSFET Q3, the anode of the diode D2, and the feedback pin of the charging chip U2; the positive detection pin of the charging chip U2 is connected to the other end of the resistor R5 and one end of the inductor L1; and the other end of the inductor L1 is connected to the drain of the driving transistor Q1.

[0010] In some embodiments, the charging module includes an indicator circuit for indicating the charging status, one end of which is connected to the power source, and the other end of which is connected to the battery charging indicator pin and the battery completion indicator pin of the charging chip U2.

[0011] In some embodiments, the indicator circuit includes a light module LED1, a resistor R6, and a resistor R7; a first end of the light module LED1 is connected to the battery completion indicator pin of the charging chip U2, a second end of the light module LED1 is connected to the battery charging indicator pin of the charging chip U2, a third end of the light module LED1 is connected to one end of the resistor R6, and a fourth end of the light module LED1 is connected to one end of the resistor R7, wherein the other ends of the resistor R6 and the other ends of the resistor R7 are both used to connect to the power supply.

[0012] In some embodiments, the charging module further includes capacitors C1, C2, C3, and C4; one end of capacitor C1 is connected to the clamping pin of the charging chip U2, and the other end of capacitor C1 is connected to one end of resistor R1, one end of capacitor C2, one end of capacitor C3, the drive voltage pin of the charging chip U2, and the power supply, wherein the other end of capacitor C2 is connected to the other end of capacitor C3 and grounded; one end of capacitor C4 is connected to both the drive voltage pin and the chip power supply pin of the charging chip U2, and the other end of capacitor C4 is grounded.

[0013] In some embodiments, the charging module further includes a capacitor C7, a resistor R8, and a diode D1; one end of the resistor R8 is connected to the stability compensation pin of the charging chip U2, the other end of the resistor R8 is connected to one end of the capacitor C7, and the other end of the capacitor C7 is grounded; the cathode of the diode D1 is connected to the drain of the driving transistor Q1 and the other end of the inductor L1, and the anode of the diode D1 is grounded.

[0014] In some embodiments, the charging chip U2 is model SLM6900.

[0015] Secondly, this application provides an anti-backflow lithium battery charging device, including the anti-backflow lithium battery charging circuit described above.

[0016] Implementing one of the above-mentioned technical solutions of this application has the following advantages or beneficial effects: In this application, when the anti-backflow lithium battery charging circuit is connected to the power supply and the battery, that is, when charging is required, the monitoring chip U1 outputs a high-level signal to control the conduction of MOSFETs Q2 and Q3, so that diode D2 is bypassed, thereby reducing the voltage drop to close to 0V and the power consumption to almost zero, thus improving the charging efficiency; when the anti-backflow lithium battery charging circuit is not connected to the power supply and the battery, the monitoring chip U1 outputs a low-level signal to control the cutoff of MOSFETs Q2 and Q3, at which time the reverse current can be blocked by diode D2. Therefore, the anti-backflow lithium battery charging circuit of this application can improve the charging efficiency during charging and effectively block the reverse current when charging stops. Furthermore, this application has the characteristics of simple circuit structure and low cost. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0018] Figure 1 This is a circuit diagram of the anti-backflow lithium battery charging circuit according to an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments and depict various exemplary embodiments that may be adopted to implement this application. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of this application disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of this application.

[0020] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0021] To illustrate the technical solutions described in this application, specific embodiments are provided below, showing only the parts related to the embodiments of this application.

[0022] like Figure 1 As shown, this application provides a reverse-current-proof lithium battery charging circuit, including: a charging module and a reverse-current-proof module;

[0023] The charging module is used to connect to the power source, and the anti-backflow module is used to connect to the battery. That is, when charging is needed, the charging module can connect to the power source to receive electrical energy and deliver it to the battery through the anti-backflow module; when charging is not needed, the charging module can be disconnected from the power source, and the anti-backflow module can block reverse current.

[0024] In some embodiments, the anti-backflow module may include a monitoring chip U1, a MOSFET Q2, a MOSFET Q3, and a diode D2. Figure 1 The Vin+ terminal shown is the power source, and the P+ terminal is the battery.

[0025] In some embodiments, the input terminal VIN of the monitoring chip U1 can be connected to a power supply, and the output terminal VOUT of the monitoring chip U1 can be connected to the gate of MOSFET Q2. The source of MOSFET Q2 is grounded, the drain of MOSFET Q2 is connected to the gate of MOSFET Q3, the drain of MOSFET Q3 is connected to the anode of diode D2 and the charging module, and the source of MOSFET Q3 is connected to the cathode of diode D2 and the battery. The reverse current protection module can generate high and low level signals at the output terminal VOUT of the monitoring chip U1 according to the power supply connection, so as to control MOSFETs Q2 and Q3 to be turned on or off simultaneously.

[0026] Specifically, when the charging module is connected to the power supply, that is, when the battery needs to be charged, the input terminal VIN of the monitoring chip U1 can receive a voltage signal from the power supply. The monitoring chip U1 generates a high-level signal at the output terminal VOUT according to the voltage signal. The high-level signal acts on the gate of MOSFET Q2, causing MOSFET Q2 to conduct. After MOSFET Q2 conducts, the gate voltage of MOSFET Q3 is less than the source voltage, which means that MOSFET Q3 is also conducted. At this time, due to the low internal resistance of MOSFET Q3, diode D2 is bypassed, thereby making the voltage drop close to 0V and the power consumption close to 0, thus achieving high-efficiency charging.

[0027] Specifically, when the charging module is not connected to the power supply, the monitoring chip U1 generates a low-level signal at the output terminal VOUT. The low-level signal acts on the gate of MOSFET Q2, causing MOSFET Q2 to turn off, which in turn causes MOSFET Q3 to turn off at the same time. At this time, diode D2 works normally and can be used to block the reverse current from the battery.

[0028] In some embodiments, the backflow prevention module may further include resistors R1, R2, R3, and R4, and capacitors C5 and C6. One end of resistor R1 can be connected to both the power supply and the charging module, and the other end of resistor R1 is connected to the input terminal VIN of monitoring chip U1 and one end of resistor R2. The other end of resistor R2 is connected to the ground terminal of monitoring chip U1 and grounded. One end of resistor R3 is connected to the drain of MOSFET Q2, and the other end of resistor R3 is connected to the gate of MOSFET Q3 and one end of resistor R4. The other end of resistor R4 is connected to the source of MOSFET Q3, the cathode of diode D2, one end of capacitor C6, and the battery, wherein one end of capacitor C6 is grounded. One end of capacitor C5 is connected to the drain of MOSFET Q3, the anode of diode D2, and the charging module, and the other end of capacitor C5 is grounded.

[0029] In some embodiments, the charging module may include a charging chip U2, a driving transistor Q1, an inductor L1, and a resistor R5. The driving pin of the charging chip U2 can be connected to the gate of the driving transistor Q1. The driving voltage pin of the charging chip U2 is connected to the power supply, the other end of the resistor R1, and the source of the driving transistor Q1. The negative detection pin of the charging chip U2 is connected to one end of the resistor R5, one end of the capacitor C5, the drain of the MOSFET Q3, the anode of the diode D2, and the feedback pin of the charging chip U2. The positive detection pin of the charging chip U2 is connected to the other end of the resistor R5 and one end of the inductor L1. The other end of the inductor L1 is connected to the drain of the driving transistor Q1.

[0030] like Figure 1As shown, pin 1 of charging chip U2 can be used as the drive pin, pin 2 as the drive voltage pin, pin 10 as the negative terminal detection pin, pin 9 as the feedback pin, and pin 11 as the positive terminal detection pin. Specifically, the drive pin of charging chip U2 can be used to control the on / off state of drive transistor Q1 to control battery charging; the drive voltage pin can be used to input drive voltage to drive transistor Q1; the negative and positive terminal detection pins of charging chip U2 can be used to detect charging current. The negative terminal detection pin of charging chip U2 can be connected to the negative terminal of resistor R5, and the positive terminal detection pin can be connected to the positive terminal of resistor R5. In this case, resistor R5 can be used as a charging current setting resistor.

[0031] In some embodiments, the charging module may include an indicator circuit for indicating the charging status. One end of the indicator circuit may be connected to a power source, and the other end of the indicator circuit may be connected to the battery charging indicator pin and the battery completion indicator pin of the charging chip U2.

[0032] like Figure 1 As shown, pin 4 of charging chip U2 can be used as the battery charging indicator pin, and pin 5 of charging chip U2 can be used as the battery completion indicator pin. When the battery is charging, the battery charging indicator pin of charging chip U2 is pulled low; when the battery is finished charging, the battery completion indicator pin of charging chip U2 is pulled low.

[0033] In some embodiments, the indicator circuit may include a light module LED1, resistor R6, and resistor R7. A first terminal of the light module LED1 can be connected to the battery completion indicator pin of the charging chip U2, a second terminal of the light module LED1 can be connected to the battery charging indicator pin of the charging chip U2, a third terminal of the light module LED1 can be connected to one end of resistor R6, and a fourth terminal of the light module LED1 can be connected to one end of resistor R7. The other ends of resistors R6 and R7 are both used to connect to a power source.

[0034] Specifically, the lighting module LED1 may include two photodiodes, wherein the cathodes of the two photodiodes are the first and second terminals of the lighting module LED1, respectively, and the anodes of the two photodiodes are the third and fourth terminals of the lighting module LED1, respectively.

[0035] In some embodiments, the charging module may further include capacitors C1, C2, C3, and C4.

[0036] In some embodiments, one end of capacitor C1 can be connected to the clamping pin of charging chip U2, and the other end of capacitor C1 can be connected to one end of resistor R1, one end of capacitor C2, one end of capacitor C3, the drive voltage pin of charging chip U2, and the power supply. The other end of capacitor C2 can be connected to the other end of capacitor C3 and grounded. One end of capacitor C4 is connected to both the drive voltage pin and the power supply pin of charging chip U2, and the other end of capacitor C4 is grounded.

[0037] In some embodiments, the charging module may further include a capacitor C7, a resistor R8, and a diode D1.

[0038] In some embodiments, one end of resistor R8 can be connected to the stability compensation pin of charging chip U2, and the other end of resistor R8 can be connected to one end of capacitor C7, with the other end of capacitor C7 grounded. The cathode of diode D1 is connected to the drain of driving transistor Q1 and the other end of inductor L1, while the anode of diode D1 is grounded.

[0039] like Figure 1 As shown, pin 3 of charging chip U2 can be the chip power supply pin of charging chip U2, pin 8 of charging chip U2 can be the stability compensation pin of charging chip U2, and pin 14 of charging chip U2 can be the clamping pin of charging chip U2.

[0040] In some embodiments, the charging chip U2 can be an SLM6900. The driving transistor Q1 can be an NCE40P05S. The first, second, and third terminals of the driving transistor Q1 can be the source of the driving transistor Q1, the fourth terminal of the driving transistor Q1 can be the gate of the driving transistor Q1, and the fifth, sixth, seventh, and eighth terminals of the driving transistor Q1 can be the drain of the driving transistor Q1.

[0041] In this application, when the anti-backflow lithium battery charging circuit is connected to the power supply and the battery, i.e., when charging is required, the monitoring chip U1 outputs a high-level signal to control the conduction of MOSFETs Q2 and Q3, thereby bypassing diode D2. This results in a voltage drop close to 0V and power consumption almost zero, thus improving charging efficiency. When the anti-backflow lithium battery charging circuit is not connected to the power supply and the battery, the monitoring chip U1 outputs a low-level signal to control the cutoff of MOSFETs Q2 and Q3. In this case, diode D2 blocks the reverse current. Therefore, the anti-backflow lithium battery charging circuit of this application can improve charging efficiency during charging and effectively block reverse current when charging stops. Furthermore, this application features a simple circuit structure and low cost.

[0042] This application also relates to an anti-backflow lithium battery charging device (not shown in the figure), which includes the anti-backflow lithium battery charging circuit described above.

[0043] The above description is merely a preferred embodiment of this application. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this application. Furthermore, under the teachings of this application, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this application. Therefore, this application is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this application.

Claims

1. A reverse current preventing lithium battery charging circuit, characterized by, The application relates to a charging module and an anti-backflow module. The charging module is used for connecting a power supply, and the anti-backflow module is used for connecting a battery. The anti-backflow module comprises a monitoring chip U1, MOS tubes Q2 and Q3 and a diode D2; an input end VIN of the monitoring chip U1 is used for being connected with the power supply, an output end VOUT of the monitoring chip U1 is connected with a gate of the MOS tube Q2, a source of the MOS tube Q2 is grounded, a drain of the MOS tube Q2 is connected with a gate of the MOS tube Q3, a drain of the MOS tube Q3 is connected with an anode of the diode D2 and the charging module, and a source of the MOS tube Q3 is connected with a cathode of the diode D2 and the battery. The anti-backflow module generates high and low level signals at the output end VOUT of the monitoring chip U1 according to the connection state of the power supply, so as to control the MOS tube Q2 and the MOS tube Q3 to be simultaneously turned on or turned off. The anti-backflow module further comprises resistors R1, R2, R3, R4, capacitors C5 and C6; one end of the resistor R1 is connected with the power supply and the charging module, the other end of the resistor R1 is connected with the input end VIN of the monitoring chip U1 and one end of the resistor R2, the other end of the resistor R2 is connected with a grounding end of the monitoring chip U1 and grounded; one end of the resistor R3 is connected with the drain of the MOS tube Q2, the other end of the resistor R3 is connected with the gate of the MOS tube Q3 and one end of the resistor R4, the other end of the resistor R4 is connected with the source of the MOS tube Q3, the cathode of the diode D2, one end of the capacitor C6 and the battery, wherein one end of the capacitor C6 is grounded; one end of the capacitor C5 is connected with the drain of the MOS tube Q3, the anode of the diode D2 and the charging module, and the other end of the capacitor C5 is grounded.

2. The reverse current preventing lithium battery charging circuit according to claim 1, wherein, The charging module comprises a charging chip U2 and a driving tube Q1; a driving pin of the charging chip U2 is connected with the gate of the driving tube Q1, a driving voltage pin of the charging chip U2 is connected with the power supply, the other end of the resistor R1 and the source of the driving tube Q1, and the drain of the driving tube Q1 is connected with the drain of the MOS tube Q3 and the anode of the diode D2.

3. The reverse current blocking lithium battery charging circuit of claim 2, wherein, The charging module comprises an inductor L1 and a resistor R5; a negative end detection pin of the charging chip U2 is connected with one end of the resistor R5, one end of the capacitor C5, the drain of the MOS tube Q3, the anode of the diode D2 and a feedback pin of the charging chip U2, a positive end detection pin of the charging chip U2 is connected with the other end of the resistor R5 and one end of the inductor L1, and the other end of the inductor L1 is connected with the drain of the driving tube Q1.

4. The reverse current preventing lithium battery charging circuit according to claim 3, wherein, ​ 5. The reverse current preventing lithium battery charging circuit according to claim 3, wherein, The charging module comprises an indicating circuit for indicating the charging state, one end of the indicating circuit is connected to the power supply, and the other end of the indicating circuit is connected to the battery charging indication pin and the battery completion indication pin of the charging chip U2.

6. The reverse current blocking lithium battery charging circuit of claim 5, wherein, The indicating circuit comprises a light module LED1, a resistor R6 and a resistor R7; the first end of the light module LED1 is connected to the battery completion indication pin of the charging chip U2, the second end of the light module LED1 is connected to the battery charging indication pin of the charging chip U2, the third end of the light module LED1 is connected to one end of the resistor R6, and the fourth end of the light module LED1 is connected to one end of the resistor R7, wherein the other end of the resistor R6 and the other end of the resistor R7 are both connected to the power supply.

7. The reverse current blocking lithium battery charging circuit of claim 3, wherein, The charging module further comprises a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4; one end of the capacitor C1 is connected to the clamping pin of the charging chip U2, and the other end of the capacitor C1 is connected to one end of the resistor R1, one end of the capacitor C2, one end of the capacitor C3, the driving voltage pin of the charging chip U2 and the power supply, wherein the other end of the capacitor C2 and the other end of the capacitor C3 are connected and grounded; one end of the capacitor C4 is connected to the driving voltage pin and the chip power supply pin of the charging chip U2, and the other end of the capacitor C4 is grounded.

8. The reverse current blocking lithium battery charging circuit of claim 4, wherein, The charging module further comprises a capacitor C7, a resistor R8 and a diode D1; one end of the resistor R8 is connected to the stable compensation pin of the charging chip U2, the other end of the resistor R8 is connected to one end of the capacitor C7, and the other end of the capacitor C7 is grounded; the cathode of the diode D1 is connected to the drain of the driving tube Q1 and the other end of the inductor L1, and the anode of the diode D1 is grounded.

9. The reverse current blocking lithium battery charging circuit of claim 3, wherein, The model of the charging chip U2 is SLM6900.

10. A reverse flow prevention lithium battery charging device, characterized by, The anti-inverted lithium battery charging circuit comprises the anti-inverted lithium battery charging circuit according to any one of claims 1 to 9.

Images