Boost-buck controllable charging and discharging circuit, method, charging line and terminal device

Abstract

The present disclosure relates to a battery's boost-buck controllable charging and discharging circuit, method, charging line and terminal device. The circuit comprises a Boost circuit module, a Buck circuit module, a charge pump circuit module, an auxiliary Buck circuit module, a battery charging and discharging control module and a system power supply module; the input end of the Boost circuit module, the Buck circuit module and the charge pump circuit module is externally connected with an AC / DC adapter; the battery charging and discharging control module is connected with the controlled end of the Boost circuit module, the controlled end of the Buck circuit module, the controlled end of the charge pump circuit module, a double-cell battery and the controlled end of the auxiliary Buck circuit module; the output end of the Buck circuit module and the auxiliary Buck circuit module is connected with the system power supply module; and the output end of the Boost circuit module, the output end of the charge pump circuit module and the input end of the auxiliary Buck circuit module are connected with the double-cell battery.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of battery charging, and particularly relates to a boost-buck controllable charging and discharging circuit, method, charging line and terminal device. BACKGROUND

[0002] A charging battery is a rechargeable battery with limited charging times, which can be used with a charger. Through charging of the battery, the battery can be reused, which is conducive to meeting the needs of economic and environmental protection. The charging process of the battery is the reverse process of the discharging process, specifically, the process of converting electrical energy into chemical energy stored in the battery.

[0003] In the current terminal device, a single cell battery is mainly used for charging. However, when the single cell battery is fully charged, the voltage is about 4.5V, and when the charging current exceeds 8A, the battery end circuit board will heat up very seriously. For this, the battery connector also needs to be replaced with a battery connector with smaller impedance and larger current flow, resulting in an increase in hardware cost; at the same time, the wiring and heat dissipation treatment in the battery end circuit board will be more difficult. In order to meet the heat dissipation requirement, the charging power of the battery end of the single cell battery is usually about 36W, resulting in a low charging efficiency. SUMMARY

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a boost-buck controllable charging and discharging circuit, method, charging line and terminal device capable of improving charging efficiency.

[0005] The present disclosure provides a boost-buck controllable charging and discharging circuit for charging a double cell battery, the circuit comprising: a Boost boost circuit module, a Buck buck circuit module, a charge pump circuit module, an auxiliary buck circuit module, a battery charging and discharging control module and a system power supply module;

[0006] The input end of the Boost boost circuit module, the input end of the Buck buck circuit module and the input end of the charge pump circuit module are respectively connected with an alternating current-direct current adapter, the battery charging and discharging control module is connected with the controlled end of the Boost boost circuit module, the controlled end of the Buck buck circuit module, the controlled end of the charge pump circuit module, the double cell battery and the controlled end of the auxiliary buck circuit module, the output end of the Buck buck circuit module and the output end of the auxiliary buck circuit module are respectively connected with the system power supply module, and the output end of the Boost boost circuit module, the output end of the charge pump circuit module and the input end of the auxiliary buck circuit module are respectively connected with the double cell battery;

[0007] The battery charging and discharging control module is a control module for controlling the Boost boost circuit module, the Buck buck circuit module, the charge pump circuit module and the auxiliary buck circuit module to work in the corresponding charging and discharging phase.

[0008] The boost circuit module works in a trickle charging phase, a constant voltage charging phase and a charging cutoff phase;

[0009] The charge pump circuit module works in a constant current charging phase, so that the current output by the charge pump circuit module is greater than the input current, and the voltage output by the charge pump circuit module is less than the input voltage;

[0010] The Buck circuit module works in a constant current charging phase, a constant voltage charging phase and a charging cutoff phase, which is a circuit module for converting the charging voltage into a voltage suitable for the system power supply module;

[0011] The auxiliary Buck circuit module works in a discharging phase, which is a circuit module for converting the discharging voltage of the double-cell battery into a voltage suitable for the system power supply module.

[0012] In some embodiments, the charge pump circuit module includes N charge pump circuit sub-modules arranged in parallel; N≥1 and is an integer;

[0013] The controlled ends of the N charge pump circuit sub-modules are respectively connected to the battery charging and discharging control module.

[0014] In some embodiments, the auxiliary Buck circuit module includes a Buck circuit sub-module or a charge pump circuit sub-module.

[0015] In some embodiments, the Buck circuit module and the Buck circuit sub-module both include:

[0016] A Buck controller, a first input capacitor, a first output capacitor, an output inductor and a first charging voltage and current controller, the Buck controller including a first transistor and a second transistor;

[0017] The battery information of the system power supply module is transmitted to the first charging voltage and current controller, the first transistor and the output inductor are connected in series, the input end of the first transistor serves as the input end of the Buck circuit module or the Buck circuit sub-module, the output end of the output inductor serves as the output end of the Buck circuit module or the Buck circuit sub-module, the first input capacitor is connected in series between the input end of the first transistor and the ground, the first output capacitor is connected in series between the output end of the output inductor and the ground, one end of the second transistor is connected between the first transistor and the output inductor, and the other end is grounded;

[0018] In the charging phase of the output inductor, the first transistor is turned on, and the second transistor is turned off;

[0019] In the discharging phase of the output inductor, the first transistor is turned off, and the second transistor is turned on.

[0020] In some embodiments, the charge pump circuit sub-module comprises: a first capacitor, a second capacitor, a third capacitor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor;

[0021] The input end of the third transistor and one end of the third capacitor are connected, and serve as the input end of the charge pump circuit sub-module, the other end of the third capacitor is grounded, the output end of the third transistor and the input end of the fourth transistor are both connected to the first end of the first capacitor, the other end of the first capacitor is connected to the input end of the sixth transistor and the output end of the fifth transistor, the output end of the sixth transistor is grounded, the output end of the fourth transistor and the input end of the fifth transistor are both connected to one end of the second capacitor, and serve as the output end of the charge pump circuit sub-module, the other end of the second capacitor is grounded;

[0022] In the capacitor series connection stage, the third transistor and the fifth transistor are turned on, and the fourth transistor and the sixth transistor are turned off;

[0023] In the capacitor parallel connection stage, the fourth transistor and the sixth transistor are turned on, and the third transistor and the fifth transistor are turned off.

[0024] In some embodiments, the charge pump circuit sub-module comprises: a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, a twelfth transistor and a thirteenth transistor;

[0025] One end of the fourth capacitor and the input end of the seventh transistor are connected, and serve as the input end of the charge pump circuit sub-module, the other end of the fourth capacitor is grounded, the output end of the seventh transistor and the input end of the eighth transistor are both connected to one end of the fifth capacitor, the other end of the fifth capacitor is connected to the input end of the ninth transistor and the input end of the tenth transistor, the output end of the ninth transistor and the output end of the thirteenth transistor are both grounded, the input end of the thirteenth transistor and the output end of the twelfth transistor are both connected to one end of the sixth capacitor, the other end of the sixth capacitor is connected to the output end of the tenth transistor and the output end of the eleventh transistor, the output end of the eighth transistor, the input end of the eleventh transistor and the input end of the twelfth transistor are all connected to one end of the seventh capacitor, and serve as the output end of the charge pump sub-module, the other end of the seventh capacitor is grounded;

[0026] In the capacitor series connection stage, the seventh transistor, the tenth transistor and the twelfth transistor are turned on, and the eighth transistor, the ninth transistor, the eleventh transistor and the thirteenth transistor are turned off;

[0027] In the capacitor parallel connection stage, the eighth transistor, the ninth transistor, the eleventh transistor and the thirteenth transistor are turned on, and the seventh transistor, the tenth transistor and the twelfth transistor are turned off.

[0028] In some embodiments, the Boost voltage increasing circuit module comprises a Boost controller, a second input capacitor, a second output capacitor, an input inductor and a second charging voltage and current controller, the Boost controller comprising a fourteenth transistor and a fifteenth transistor;

[0029] The battery information of the double-cell battery is transmitted to the second charging voltage and current controller, the input inductor and the fourteenth transistor are connected in series between the AC / DC adapter and the double-cell battery, the second input capacitor is connected in series between the input end of the input inductor and the ground, the second output capacitor is connected in series between the output end of the fourteenth transistor and the ground, one end of the fifteenth transistor is connected between the fourteenth transistor and the input inductor, and the other end is grounded;

[0030] In the charging stage of the input inductor, the fourteenth transistor is turned off, and the fifteenth transistor is turned on;

[0031] In the discharging stage of the input inductor, the fourteenth transistor is turned on, and the fifteenth transistor is turned off.

[0032] The present disclosure also provides a boost-buck controllable charging and discharging method, which is based on any of the above charging and discharging circuits, and the method comprises:

[0033] The battery charging and discharging control module collects the charging voltage and the charging current of the double-cell battery in real time, and determines the charging and discharging stage of the double-cell battery based on the charging voltage and the charging current;

[0034] In the trickle charging stage, the battery charging and discharging control module controls the Boost voltage increasing circuit module to be turned on to work;

[0035] In the constant current charging stage, the battery charging and discharging control module controls the charge pump circuit module and the Buck voltage decreasing circuit module to be turned on to work, so that the current output by the charge pump circuit module is greater than the input current, and the voltage output by the charge pump circuit module is less than the input voltage;

[0036] In the constant voltage charging stage and the charging cutoff stage, the battery charging and discharging control module controls the charge pump circuit module to be turned off, the Boost voltage increasing circuit module to be turned on, and the Buck voltage decreasing circuit module to be turned on;

[0037] In the discharging stage, the battery charging and discharging control module controls the auxiliary voltage decreasing circuit module to be turned on to transform the discharging voltage of the double-cell battery into a voltage suitable for the system power supply module.

[0038] The present disclosure also provides a charging line comprising any of the above charging and discharging circuits.

[0039] The terminal device comprises a double-electricity-core battery, the double-electricity-core battery is charged by using any one of the charging and discharging circuits, or is charged by using any one of the charging and discharging methods, or is charged based on any one of the charging wires.

[0040] Compared with the prior art, the technical scheme provided by the embodiments of the present disclosure has the following advantages:

[0041] The buck-controllable charging and discharging circuit provided by the embodiments of the present disclosure is a charging and discharging circuit for a double-electricity-core battery. In the charging phase, a Buck step-down circuit module is used to supply power to a system power supply module. In the discharging phase, an auxiliary step-down circuit module is used to supply power to the system power supply module. In this way, the double-electricity-core battery can be prevented from being charged and discharged at the same time, and the system can be powered, thereby effectively protecting the battery. In the trickle charging, constant voltage charging and charging cutoff phases, the current is small and the heat generation is less, so a Boost step-up circuit module can be used for charging current control, which is simpler and has higher flexibility. In the constant current charging phase, a charge pump circuit module is used for charging current control, so that the output current of the charge pump circuit module is greater than the input current. When large current charging is implemented, the current transmitted on the charging wire can be reduced. Since the charging wire has a certain impedance, based on the power calculation formula I 2 R, the power corresponds to the heat generation. When the current is reduced, the heat generation is also reduced, thereby reducing the heat generation on the charging wire. Similarly, the heat generation on the charging chip and the PCB can be reduced, that is, the heat generation of the entire charging circuit is reduced, thereby ensuring high charging efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0044] Figure 1 A structural schematic diagram of a charging and discharging circuit provided by the embodiments of the present disclosure is shown in the figure.

[0045] Figure 2 A structural schematic diagram of another charging and discharging circuit provided by the embodiments of the present disclosure is shown in the figure.

[0046] Figure 3 A structural schematic diagram of a connection relationship of a Buck step-down circuit module in a charging and discharging circuit provided by the embodiments of the present disclosure is shown in the figure.

[0047] Figure 4 A state diagram of the inductor in the Buck voltage reduction circuit module provided by the embodiment of the present disclosure in the charging stage;

[0048] Figure 5 A state diagram of the inductor in the Buck voltage reduction circuit module provided by the embodiment of the present disclosure in the discharging stage;

[0049] Figure 6 A structure diagram of a charge pump circuit submodule provided by the embodiment of the present disclosure;

[0050] Figure 7 A state diagram of the charge pump circuit submodule in the capacitor series stage; Figure 6 A state diagram of the charge pump circuit submodule in the capacitor series stage;

[0051] Figure 8 A state diagram of the charge pump circuit submodule in the capacitor parallel stage; Figure 6 A state diagram of the charge pump circuit submodule in the capacitor parallel stage;

[0052] Figure 9 A structure diagram of another charge pump circuit submodule provided by the embodiment of the present disclosure;

[0053] Figure 10 A state diagram of the charge pump circuit submodule in the capacitor series stage; Figure 9 A state diagram of the charge pump circuit submodule in the capacitor series stage;

[0054] Figure 11 A state diagram of the charge pump circuit submodule in the capacitor parallel stage; Figure 9 A state diagram of the charge pump circuit submodule in the capacitor parallel stage;

[0055] Figure 12 A structure diagram of the connection relationship of the Boost voltage increase circuit module in the charging and discharging circuit provided by the embodiment of the present disclosure;

[0056] Figure 13 A state diagram of the inductor in the Boost voltage increase circuit module provided by the embodiment of the present disclosure in the charging stage;

[0057] Figure 14 A state diagram of the inductor in the Boost voltage increase circuit module provided by the embodiment of the present disclosure in the discharging stage;

[0058] Figure 15 A flow diagram of a charging and discharging method provided by the embodiment of the present disclosure.

[0059] Wherein, 010, double battery core; 020, AC adapter; 110, Boost circuit module, 120, Buck circuit module; 130, charge pump circuit module; 135, charge pump circuit sub-module; 140, auxiliary Buck circuit module; 150, battery charge and discharge control module; 160, system power module; 201, Buck controller; 202, the first input capacitor; 203, the first output capacitor; 204, output inductor; 205, the first charging voltage current controller; 301, Boost controller; 302, the second input capacitor; 303, the second output capacitor; 304, input inductor; 305, the second charging voltage current controller; C1, the first capacitor; C2, the second capacitor; C3, the third capacitor; C4, the fourth capacitor; C5, the fifth capacitor; C6, the sixth capacitor; C7, the seventh capacitor; Q1, the first transistor; Q2, the second transistor; Q3, the third transistor; Q4, the fourth transistor; Q5, the fifth transistor; Q6, the sixth transistor; Q7, the seventh transistor; Q8, the eighth transistor; Q9, the ninth transistor; Q10, the tenth transistor; Q11, the eleventh transistor; Q12, the twelfth transistor; Q13, the thirteenth transistor; Q14, the fourteenth transistor; Q15, the fifteenth transistor. DETAILED DESCRIPTION

[0060] In order to enable a more clear understanding of the above-mentioned objects, features and advantages of the present disclosure, the schemes of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0061] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present disclosure, but the present disclosure can also be implemented in other manners different from those described herein; obviously, the embodiments described in the specification are only a part of the embodiments of the present disclosure, and not all the embodiments.

[0062] The charging circuit of the battery provided by the embodiments of the present disclosure is a charging circuit for a double battery core, which includes a Boost circuit module and a charge pump circuit module. In the trickle charging, constant voltage charging and subsequent charging cutoff stage, since the current is small and the heat generation is small, the Boost circuit module is used for control, which is more simple and has higher flexibility. In the constant current charging stage, the charge pump circuit module is used for control, which has higher charging efficiency and reduces heat generation in the large current charging. Optionally, the charge pump circuit module can use a 1 / 2 times step-down charge pump (the input voltage is 2 times the output voltage, and the input current is 1 / 2 the output current), a 1 / 3 times step-down charge pump (the input voltage is 3 times the output voltage, and the input current is 1 / 3 the output current), or other types of step-down charge pumps, which are not limited herein.

[0063] In addition, in the charging stage, the system power supply module can be powered by using a Buck step-down circuit module; the double-cell battery can be prevented from being charged and discharged at the same time, system power supply can be realized, and thus the double-cell battery can be effectively protected. In the discharging stage, an auxiliary step-down circuit module, which can be a Buck step-down circuit submodule or a charge pump circuit submodule, can be used to step down the output voltage of the double-cell battery, power the system power supply module, and realize system power supply.

[0064] The embodiments of the present disclosure are described below in conjunction with Figures 1-15 The charging circuit, the charging method, the charging line, and the terminal device of the double-cell battery provided by the embodiments of the present disclosure are described exemplarily.

[0065] Figure 1 A structure diagram of a charging and discharging circuit provided by an embodiment of the present disclosure is shown. Refer to Figure 1The charging and discharging circuit is used for charging the double-cell battery 010, and can include a Boost circuit module 110, a Buck circuit module 120, a charge pump circuit module 130, an auxiliary Buck circuit module 140, a battery charging and discharging control module 150, and a system power supply module 160. The input end of the Boost circuit module 110, the input end of the Buck circuit module 120, and the input end of the charge pump circuit module 130 are respectively connected to an AC / DC adapter 020. The battery charging and discharging control module 150 is connected to the controlled end of the Boost circuit module 110, the controlled end of the Buck circuit module 120, the controlled end of the charge pump circuit module 130, the double-cell battery 010, and the controlled end of the auxiliary Buck circuit module 140. The output end of the Buck circuit module 120 and the output end of the auxiliary Buck circuit module 140 are respectively connected to the system power supply module 160. The output end of the Boost circuit module 110, the output end of the charge pump circuit module 130, and the input end of the auxiliary Buck circuit module 140 are respectively connected to the double-cell battery 010. The battery charging and discharging control module 150 is a control module for controlling the Boost circuit module 110, the Buck circuit module 120, the charge pump circuit module 130, and the auxiliary Buck circuit module 140 to work in corresponding charging and discharging stages. The Boost circuit module 110 works in a trickle charging stage, a constant voltage charging stage, and a charging cutoff stage. The charge pump circuit module 130 works in a constant current charging stage, so that the output current of the charge pump circuit module 130 is greater than the input current, and the output voltage of the charge pump circuit module 130 is less than the input voltage. The Buck circuit module 120 works in a constant current charging stage, a constant voltage charging stage, and a charging cutoff stage, so that the charging voltage is converted into a voltage suitable for the system power supply module 160. The auxiliary Buck circuit module 140 works in a discharging stage, so that the discharging voltage of the double-cell battery 010 is converted into a voltage suitable for the system power supply module 160. Hereinafter, the double-cell battery can also be referred to as a battery.

[0066] In the embodiments of the present disclosure, the charging stage of the battery can include a trickle charging stage, a constant current charging stage, a constant voltage charging stage, and a charging cutoff stage. The trickle charging stage can be understood as a "pre-charging stage", which is a small current charging stage. The constant current charging stage is a stage in which a constant current value is used for charging, and in this stage, the charging voltage gradually increases. The constant voltage charging stage is a stage in which a constant voltage value is used for charging, and in this stage, the charging current gradually decreases. In the charging cutoff stage, the charging current becomes smaller and smaller, and when it is small to a certain extent, it corresponds to the state of the battery being fully charged. For example, at this time, the user is prompted to fully charge.

[0067] Exemplarily, in the charging phase, for different phases, the circuit modules can work as follows.

[0068] In the trickle charging phase, when the voltage of the battery is lower than 6V or a voltage value around 6V, the battery can be charged with a constant current of maximum 0.1C.

[0069] Exemplarily, the battery charging and discharging control module 150 can determine the port type of the power adapter (i.e. AC / DC adapter 020), which can include, for example, a standard downstream port (SDP), a dedicated charging port (DCP) or a charging downstream port (CDP), or other port types known to those skilled in the art.

[0070] When the port type of the AC / DC adapter 020 is a standard downstream port SDP, it means that the port is a USB interface that can be plugged into a computer, with a current of 500mA and a voltage of 5V. When the port type of the AC / DC adapter 020 is a charging downstream port CDP, it is similar to a hub, which can be a hub with multiple interfaces, with a current of 1A-1.5A and a voltage of 5V. In the above two cases, the output voltage of the AC / DC adapter 020 is also 5V. The battery charging and discharging control module 150 can control the Boost circuit module 110 to be turned on and work for small current charging, and the charge pump circuit module 130 can be turned off at the same time.

[0071] When the port type of the AC / DC adapter 020 is a dedicated charging port DCP, the battery charging and discharging control module 150 can also not perform boost control protocol with the AC / DC adapter 020, and the output voltage of the AC / DC adapter 020 is also 5V. The battery charging and discharging control module 150 can control the Boost circuit module 110 to be turned on and work for small current charging, and the charge pump circuit module 130 can be turned off at the same time.

[0072] In the constant current charging phase, when the charging voltage is greater than the set voltage threshold and the charging current is greater than the set current threshold (e.g. 1A or 2A), the battery charging and discharging control module 150 can control the charge pump circuit module 130 to be turned on, and the battery charging and discharging control module 150 can also perform boost control protocol with the AC / DC adapter 020 to control the AC / DC adapter 020 to output dynamic voltage and dynamic current to the charge pump circuit module 130. At this time, the charge pump circuit module 130 can perform large current charging, and the details will be described below. Figures 6-11The working principle and process of the charge pump circuit module 130 are exemplarily illustrated; at this time, the Boost circuit module 110 is closed, the Buck circuit module 120 is continuously controlled to be opened, the system power supply module 160 is powered, and thus the system is powered during the charging process without affecting the charging process of the double-cell battery 010.

[0073] During the constant-voltage charging phase and the charging cutoff phase, the charging current is less than the set current threshold, and the battery charging and discharging control module 150 does not need to perform the boost control protocol with the AC / DC adapter 020, and controls the AC / DC adapter 020 to output a voltage value lower than the battery voltage, for example, 5V or 6V. At this time, the battery charging and discharging control module 150 controls: the Boost circuit module 110 is opened, and the charge pump circuit module 130 is closed; the Buck circuit module 120 is continuously controlled to be opened, and the system power supply module 160 is powered, and thus the system is powered during the charging process without affecting the charging process of the double-cell battery 010.

[0074] During the above charging process, the voltage threshold and the current threshold can be set based on the charging requirements of the double-cell battery, which is not limited herein.

[0075] During the discharging phase, the battery charging and discharging control module 150 controls: the auxiliary Buck circuit module 140 is opened, the output voltage of the double-cell battery 010 is stepped down, and the system power supply module 160 is powered; at this time, the Buck circuit module 120 and the charge pump circuit module 130 are closed.

[0076] The system power supply module 160 mainly provides power for the system to ensure that the system can work normally.

[0077] In the charging and discharging circuit of the double-cell battery provided by the embodiments of the present disclosure, during the trickle charging, constant-voltage charging and subsequent charging cutoff phase, the current is small, the heat generation is small, the Boost circuit module 110 can be used for control, which is more simple and has higher flexibility; during the constant-current charging phase, the charge pump circuit module 130 is used for control, and during the large-current charging, the charging efficiency is high and the heat generation is reduced. In addition, during the charging phase, the Buck circuit module 120 can be used to power the system power supply module 160; the double-cell battery can be prevented from being charged and discharged at the same time, and the system can be powered, thereby effectively protecting the double-cell battery. During the discharging phase, the auxiliary Buck circuit module 140 can be used to step down the output voltage of the double-cell battery 010 and power the system power supply module 160, thereby achieving the system power supply.

[0078] The specific composition and working principle of each circuit module are exemplarily illustrated as follows. Figures 2-14 The specific composition and working principle of each circuit module are exemplarily illustrated as follows.

[0079] In some embodiments, Figure 2 This diagram illustrates a structural schematic of another charging and discharging circuit provided in an embodiment of the present disclosure. Figure 1 Based on this, the charge pump circuit module was further refined. (Refer to...) Figure 2 The charge pump circuit module 130 includes N charge pump circuit sub-modules 135 connected in parallel; N ≥ 1 and is an integer; the controlled terminals of the N charge pump circuit sub-modules 135 are respectively connected to the battery charge and discharge control module 150.

[0080] When the charging voltage is the same, the larger the charging current, the higher the charging power, but the more heat will be generated. In order to ensure a large charging power while minimizing heat generation, the charging power and heat generation are designed to be balanced. The applicable charging current range of a single charge pump circuit submodule 135 can be 4A-6A.

[0081] Based on this, by connecting multiple charge pump circuit sub-modules 135 in parallel, a charge pump circuit module 130 capable of handling larger charging currents can be constructed. In practical applications, the number of charge pump circuit sub-modules 135 connected in parallel can be selected according to the magnitude of the charging current; the larger the charging current, the more charge pump circuit sub-modules 135 are used, thus improving the overall power conversion efficiency of the charging solution and reducing heat generation.

[0082] For example, when the charging current is 8A-10A, the number of charge pump circuit sub-modules 135 connected in parallel in the charge pump circuit module 130 can be 2, and each charge pump circuit sub-module 135 shares the charging current of 4A-5A; when the charging current is 20A, the number of charge pump circuit sub-modules 135 connected in parallel in the charge pump circuit module 130 can be 4, and each charge pump circuit sub-module 135 shares the charging current of 5A.

[0083] It is understandable that the number of charge pump circuit sub-modules 135 in charge pump circuit module 130 can also be one.

[0084] In other embodiments, the number of charge pump circuit sub-modules 135 in charge pump circuit module 130 may vary when the charging current is other current values ​​or other current ranges, and is not limited here.

[0085] In some embodiments, the auxiliary buck circuit module 140 includes a Buck buck circuit submodule (not shown) or a charge pump circuit submodule 135.

[0086] In this embodiment of the disclosure, the auxiliary step-down circuit module 140 may use a Buck step-down circuit submodule or a charge pump circuit submodule to step down the voltage in order to supply power to the system power supply module 160.

[0087] It can be understood that the Buck voltage reduction circuit sub-module can adopt the same circuit structure as the Buck voltage reduction circuit module 120, which will be described below in combination with Figures 3-5 for exemplary description.

[0088] In some embodiments, Figure 3 The structure schematic diagram of the connection relationship of the Buck voltage reduction circuit module in the charging and discharging circuit in the embodiment of the present disclosure is shown, and the specific structure of the Buck voltage reduction circuit module is shown; in combination with the above, the Buck voltage reduction circuit sub-module can also adopt the circuit structure, and the difference is only that the circuit modules connected at the input and output ends are different. On the basis of Figure 1 , referring to Figure 3 , the Buck voltage reduction circuit module 120 and the Buck voltage reduction circuit sub-module both include a Buck controller 201, a first input capacitor 202, a first output capacitor 203, an output inductor 204, and a first charging voltage and current controller 205, and the Buck controller 201 includes a first transistor Q1 and a second transistor Q2; in the Buck voltage reduction circuit module 120, the battery information of the system power supply module 160 is transmitted to the first charging voltage and current controller 205, the first transistor Q1 and the output inductor 204 are connected in series between the AC / DC adapter 020 and the system power supply module 160, the first input capacitor 202 is connected in series between the input end of the first transistor Q1 and the ground, the first output capacitor 203 is connected in series between the output end of the output inductor 204 and the ground, one end of the second transistor Q2 is connected between the first transistor Q1 and the output inductor 204, and the other end is grounded; in the charging stage of the output inductor 204, the first transistor Q1 is turned on, and the second transistor Q2 is turned off; in the discharging stage of the output inductor 204, the first transistor Q1 is turned off, and the second transistor Q2 is turned on.

[0089] It can be understood that in the Buck voltage reduction circuit sub-module, the first transistor Q1 and the output inductor 204 are connected in series between the double-cell battery 010 and the system power supply module 160, and the connection relationship between other circuit components is the same as described above, which will not be described again.

[0090] Among them, the Buck voltage reduction circuit module 120 and the Buck voltage reduction circuit sub-module can both include a Buck topology structure, also known as a Buck voltage reduction circuit or a Buck circuit, and the Buck circuit mainly includes a Buck controller 201, a first input capacitor 202, a first output capacitor 203, and an output inductor 204; that is, the first input capacitor 202, the first output capacitor 203, the output inductor 204, and the Buck controller 201 constitute the Buck circuit; the first charging voltage and current controller 205 is used to control the voltage and current that change in a sawtooth shape over time.

[0091] In the whole charging and discharging circuit, the Buck circuit is the main circuit of power conversion, so the charging current size, charging efficiency and heat generation will be determined by the circuit components in the Buck circuit.

[0092] The basic working principle of the Buck circuit includes two stages, as follows:

[0093] In the first stage (Phase 1), that is, the charging stage of the output inductor 204, in combination with Figure 4 , the first transistor Q1 is turned on, the second transistor Q2 is turned off, and the output inductor 204 is charged. The first transistor Q1, the output inductor 204 and the system power supply module 160 form a main circuit, and the main current of the circuit will flow through the first transistor Q1, the output inductor 204 and the system power supply module 160.

[0094] In the second stage (Phase 2), that is, the discharging stage of the output inductor 204, in combination with Figure 5 , the first transistor Q1 is turned off, the second transistor Q2 is turned on, and the output inductor 204 is discharged. The second transistor Q2, the output inductor 204 and the system power supply module 160 form a main circuit, and the main current of the circuit will flow through the second transistor Q2, the output inductor 204 and the system power supply module 160.

[0095] Among them, in the Buck circuit, the first transistor Q1 and the second transistor Q2 will have conduction loss and switching loss, and the output inductor 204 will have coil loss and core loss, so the efficiency of the whole Buck circuit cannot be very high. At present, in the Buck circuit commonly used in the step-down circuit, the conversion efficiency is below 91%. The energy loss of the main power devices including the first transistor Q1, the second transistor Q2 and the output inductor 204 is basically converted into heat energy, which causes the Buck circuit to generate more heat when applied to the charging process, thereby causing the charging current of the whole Buck circuit to be unable to be very large.

[0096] Based on this, in the charging and discharging circuit provided in the embodiments of the present disclosure, the Buck circuit can be applied to convert the voltage at its input end into a voltage suitable for the system power supply module 160, and is not used to directly convert into a current voltage for charging the double-cell battery 010, thereby facilitating avoiding excessive heat generation in the large-current charging process and avoiding affecting the charging efficiency.

[0097] In the above embodiments, the charge pump circuit sub-module can adopt a 1 / 2 step-down charge pump, which will be exemplarily described below in combination with Figures 6-8 ; or a 1 / 3 step-down charge pump, which will be exemplarily described below in combination with Figures 9-11 .

[0098] In some embodiments, Figure 6A structural schematic diagram of a charge pump circuit sub-module provided by an embodiment of the present disclosure is shown. In Figure 1 Referring to Figure 6 , the charge pump circuit sub-module 135 comprises a first capacitor C1, a second capacitor C2, a third capacitor C3, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5 and a sixth transistor Q6. In the charge pump circuit module 130, the input end of the third transistor Q3 and one end of the third capacitor C3 are connected to the AC / DC adapter 020, the other end of the third capacitor C3 is grounded, the output end of the third transistor Q3 and the input end of the fourth transistor Q4 are both connected to the first end of the first capacitor C1, the other end of the first capacitor C1 is connected to the input end of the sixth transistor Q6 and the output end of the fifth transistor Q5, the output end of the sixth transistor Q6 is grounded, the output end of the fourth transistor Q4, the input end of the fifth transistor Q5 and one end of the second capacitor C2 are all connected to the double-core battery 010, and the other end of the second capacitor C2 is grounded. In the capacitor series stage, the third transistor Q3 and the fifth transistor Q5 are turned on, and the fourth transistor Q4 and the sixth transistor Q6 are turned off. In the capacitor parallel stage, the fourth transistor Q4 and the sixth transistor Q6 are turned on, and the third transistor Q3 and the fifth transistor Q5 are turned off.

[0099] It can be understood that, in the auxiliary step-down circuit module 140, the input end of the third transistor and one end of the third capacitor constitute the input end of the step-down charge pump and are connected to the double-core battery; the output end of the fourth transistor, the input end of the fifth transistor and one end of the second capacitor constitute the output end of the step-down charge pump and are connected to the system power supply module; the connection relationship between other circuit components is the same as described above, and will not be described again.

[0100] In the embodiment of the present disclosure, since no inductive device is needed in the circuit structure of the charge pump circuit sub-module 135, the step-down is realized only by switching between the turned-on capacitors, so there is no energy loss caused by the inductor, thereby making the conversion efficiency of the entire circuit structure higher.

[0101] The charge pump circuit sub-module 135 in the embodiment of the present disclosure adopts a 1 / 2 times step-down charge pump, the input voltage of which is twice the output voltage, and the input current is half the output current. The 1 / 2 times step-down charge pump comprises four transistors and three capacitors. By controlling the opening and closing of the transistors, the series and parallel of the capacitors are realized, thereby realizing step-down, which will be described below in combination with Figure 7 and Figure 8 .

[0102] The basic working principle of the 1 / 2 times step-down charge pump includes two stages, as follows:

[0103] The first stage (Phase 1), i.e. the capacitor series stage, or the capacitor charging stage, as shown in Figure 7As shown, only the third transistor Q3 and the fifth transistor Q5 are turned on, the first capacitor C1 and the second capacitor C2 are connected in series, and both the capacitors are charged, and the charging voltage of both the capacitors is approximately equal to half of the input voltage, that is, VIN / 2.

[0104] The second phase (Phase 2), that is, the capacitor parallel phase, or the capacitor discharge phase, is as shown in FIG. 3. Figure 8 As shown, only the fourth transistor Q4 and the sixth transistor Q6 are turned on, the first capacitor C1 and the second capacitor C2 are connected in parallel, both the capacitors are discharged, and the output voltage VOUT is equal to the discharge voltage between the second capacitor C2, and also equal to the charging voltage in the first phase, that is, VIN / 2.

[0105] In this way, the voltage is reduced.

[0106] The above Figures 6-8 exemplarily illustrates the circuit structure and working principle of the 1 / 2 voltage reduction charge pump, and the following Figures 9-11 exemplarily illustrates the circuit structure and working principle of the 1 / 3 voltage reduction charge pump.

[0107] In some embodiments, Figure 9 A structure diagram of another charge pump circuit sub-module provided by the embodiment of the present disclosure is shown. Refer to Figure 9The charge pump circuit sub-module 135 includes a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9, a tenth transistor Q10, an eleventh transistor Q11, a twelfth transistor Q12, and a thirteenth transistor Q13. In the charge pump circuit module 130, one end of the fourth capacitor C4 and an input end of the seventh transistor Q7 are connected to the AC / DC adapter 020, the other end of the fourth capacitor C4 is grounded, the output end of the seventh transistor Q7 and the input end of the eighth transistor Q8 are connected to one end of the fifth capacitor C5, the other end of the fifth capacitor C5 is connected to the input end of the ninth transistor Q9 and the input end of the tenth transistor Q10, the output end of the ninth transistor Q9 and the output end of the thirteenth transistor Q13 are grounded, the input end of the thirteenth transistor Q13 and the output end of the twelfth transistor Q12 are connected to one end of the sixth capacitor C6, the other end of the sixth capacitor C6 is connected to the output end of the tenth transistor Q10 and the output end of the eleventh transistor Q11, the output end of the eighth transistor Q8, the input end of the eleventh transistor Q11, the input end of the twelfth transistor Q12, and one end of the seventh capacitor C7 are connected to the double-cell battery 010, and the other end of the seventh capacitor C7 is grounded. In the capacitor series connection stage, the seventh transistor Q7, the tenth transistor Q10, and the twelfth transistor Q12 are turned on, and the eighth transistor Q8, the ninth transistor Q9, the eleventh transistor Q11, and the thirteenth transistor Q13 are turned off. In the capacitor parallel connection stage, the eighth transistor Q8, the ninth transistor Q9, the eleventh transistor Q11, and the thirteenth transistor Q13 are turned on, and the seventh transistor Q7, the tenth transistor Q10, and the twelfth transistor Q12 are turned off.

[0108] It can be understood that, in the auxiliary voltage reduction circuit module 140, one end of the fourth capacitor and the input end of the seventh transistor constitute the input end of the voltage reduction charge pump and are connected to the double-cell battery; the output end of the eighth transistor, the input end of the eleventh transistor, the input end of the twelfth transistor, and one end of the seventh capacitor constitute the output end of the voltage reduction charge pump and are connected to the system power supply module; the connection relationship between other circuit components is the same as described above, and will not be described again.

[0109] The charge pump circuit sub-module 135 in the embodiment of the present disclosure adopts a 1 / 3 times voltage reduction charge pump, the input voltage of which is 3 times the output voltage, and the input current is 1 / 3 of the output current. The 1 / 3 times voltage reduction charge pump includes seven transistors and four capacitors. By controlling the turn-on and turn-off of the transistors, the series and parallel connection of the capacitors are realized, so that the voltage is reduced. The following will be exemplarily described in combination with Figure 10 and Figure 11 .

[0110] The circuit working principle of the 1 / 3 times voltage reduction charge pump includes two stages, as follows:

[0111] The first phase (Phase 1), i.e. the capacitor series phase or the capacitor charging phase, as shown in FIG. 1, the seventh transistor Q7, the tenth transistor Q10 and the twelfth transistor Q12 are all closed, i.e. turned on; other transistors are open, i.e. turned off; at this time, the fifth capacitor C5, the sixth capacitor C6 and the seventh capacitor C7 are in series, and the three capacitors are all charged, and the charging voltage of each capacitor is about 1 / 3 of the input voltage, i.e. 1 / 3VIN. Figure 10

[0112] The second phase (Phase 2), i.e. the capacitor parallel phase or the capacitor discharging phase, as shown in FIG. 2, the eighth transistor Q8, the ninth transistor Q9, the eleventh transistor Q11 and the thirteenth transistor Q13 are all closed, i.e. turned on; other transistors are open, i.e. turned off; at this time, the fifth capacitor C5, the sixth capacitor C6 and the seventh capacitor C7 are in parallel, and the three capacitors are all discharged, and the output voltage VOUT is equal to the discharging voltage between the seventh capacitor C7, which is also equal to the charging voltage in the first phase, i.e. 1 / 3VIN. Figure 11

[0113] In this way, the voltage is reduced.

[0114] It can be understood that, since the input current of the 1 / 3 voltage reduction charge pump is 1 / 3 of the output current, and the input current of the 1 / 2 voltage reduction charge pump is 1 / 2 of the output current, under the condition that the output currents are the same, the input current corresponding to the 1 / 3 voltage reduction charge pump is reduced by 1 / 3 compared with the input current of the 1 / 2 voltage reduction charge pump, thereby greatly reducing the current at the input end, and further reducing the heat on the charging wire, the heat on the charging chip and the heat on the PCB, so as to ensure a high charging efficiency. In addition, under the condition that the input currents are the same, the output current of the 1 / 3 voltage reduction charge pump will be larger than that of the 1 / 2 voltage reduction charge pump, i.e. a larger charging current can be achieved, the charging efficiency is improved, and the charging time is shortened.

[0115] The circuit structure and working principle of the 1 / 2 voltage reduction charge pump are exemplarily described above, and the circuit structure and working principle of the 1 / 3 voltage reduction charge pump are exemplarily described below. Figures 6-8 Figures 9-11 In other embodiments, the charge pump circuit sub-module can also adopt a voltage reduction charge pump with other multiples, which is not limited herein.

[0116] The Boost voltage increasing circuit module is exemplarily described below. Figures 12-14

[0117] In some embodiments, Figure 12 FIG. 3 shows the connection relationship and circuit structure of a Boost voltage increasing circuit module provided by an embodiment of the present disclosure in a charging and discharging circuit. On the basis of FIG. 3, refer to FIG. 4. Figure 1 FIG. 4 shows the connection relationship and circuit structure of a Boost voltage increasing circuit module provided by an embodiment of the present disclosure in a charging and discharging circuit.​​​​Figure 12 The Boost voltage circuit module 110 comprises a Boost controller 301, a second input capacitor 302, a second output capacitor 303, an input inductor 304, and a second charging voltage and current controller 305, the Boost controller 301 comprising a fourteenth transistor Q14 and a fifteenth transistor Q15; the battery information of the double-core battery 010 is transmitted to the second charging voltage and current controller 305, the input inductor 304 and the fourteenth transistor Q14 are connected in series between the AC / DC adapter 020 and the double-core battery 010, the second input capacitor 302 is connected in series between the input end of the input inductor 304 and the ground, the second output capacitor 303 is connected in series between the output end of the fourteenth transistor Q14 and the ground, one end of the fifteenth transistor Q15 is connected between the fourteenth transistor Q14 and the input inductor 304, and the other end is grounded; in the charging stage of the input inductor 304, the fourteenth transistor Q14 is cut off, and the fifteenth transistor Q15 is turned on; in the discharging stage of the input inductor 304, the fourteenth transistor Q14 is turned on, and the fifteenth transistor Q15 is cut off.

[0118] In the embodiments of the present disclosure, the Boost voltage circuit module 110 can comprise a Boost topology, also known as a Boost voltage circuit or a Boost circuit, which mainly comprises a Boost controller 301, a second input capacitor 302, a second output capacitor 303, and an input inductor 304; that is, the Boost controller 301, the second input capacitor 302, the second output capacitor 303, and the input inductor 304 constitute a Boost circuit; and the second charging voltage and current controller 305 is used to control the voltage and current that change in a sawtooth shape over time.

[0119] In the entire charging and discharging circuit, the Boost circuit is the main loop of the power supply conversion, so the charging current size, the charging efficiency, and the heat generation amount are determined by the circuit components in the Boost circuit.

[0120] The basic working principle of the Boost circuit comprises two stages, as follows:

[0121] The first stage (Phase 1), that is, the charging stage of the input inductor 304, in combination with Figure 13 The fourteenth transistor Q14 is cut off, the fifteenth transistor Q15 is turned on, and the input inductor 304 is charged. The fifteenth transistor Q15 and the input inductor 304 form the main loop, and the main current of the circuit flows through the fifteenth transistor Q15 and the input inductor 304.

[0122] The second stage (Phase 2), that is, the discharging stage of the input inductor 304, in combination with Figure 14When the fourteenth transistor Q14 is turned on and the fifteenth transistor Q15 is turned off, the input inductor 304 is discharged. The input inductor 304, the fourteenth transistor, and the double-cell battery 010 form a main circuit, and the main current of the circuit flows through the input inductor 304, the fourteenth transistor, and the double-cell battery 010.

[0123] In this way, the boost circuit module 110 can be used to control the charging current in the trickle charging stage, the constant voltage charging stage, and the subsequent charging cutoff stage. Since the charging current is small, the heat generated is less, the control is simpler, and the flexibility is higher.

[0124] In the above embodiments, the transistors in each circuit module or sub-module can be metal-oxide-semiconductor field-effect transistors (MOSFETs) or other switch tubes known to those skilled in the art, or other types of switches, which are not limited herein.

[0125] The boost and buck controllable charging and discharging circuit for a double-cell battery provided by the embodiments of the present disclosure can improve the problem that the charging power of a single-cell battery cannot be increased. Specifically, the double-cell battery is charged, and the charging voltage is twice the charging voltage when the single-cell battery is charged. In the case of the same charging circuit, a larger charging power can be achieved. For example, a charging power of 50W, 60W, 100W, or higher can be achieved.

[0126] At the same time, since the battery charging voltage is twice the voltage of the original single-cell battery, the battery charging current is half the current of the single-cell battery at the same battery end charging power. The heat generated by the double-cell battery end circuit board is significantly reduced compared to the single-cell battery, thereby greatly reducing the heat generated. In the case of the same output power, the current is reduced, and the impedance requirement of the battery connector is reduced, which is conducive to reducing the cost. Since the heat generated is reduced, safety is improved. At the same time, the wiring and heat dissipation treatment of the battery end circuit board PCB are relatively easy.

[0127] The embodiments of the present disclosure also provide a boost and buck controllable charging and discharging method, which is executed based on any of the above charging and discharging circuits and has corresponding beneficial effects.

[0128] In some embodiments, Figure 15 A flowchart of a charging and discharging method provided by an embodiment of the present disclosure is shown. Referring to Figure 15 The method comprises the following steps.

[0129] S410, the battery charging and discharging control module collects the charging voltage and the charging current of the double-cell battery in real time, and determines the charging and discharging stage of the double-cell battery based on the charging voltage and the charging current.

[0130] S420, in the trickle charging stage, the battery charging and discharging control module controls the Boost circuit module to open to work.

[0131] S430, in the constant current charging stage, the battery charging and discharging control module controls the charge pump circuit module and the Buck circuit module to open to work, so that the current output by the charge pump circuit module is greater than the input current, and the voltage output by the charge pump circuit module is less than the input voltage.

[0132] S440, in the constant voltage charging stage and the charging cutoff stage, the battery charging and discharging control module controls the charge pump circuit module to close, the Boost circuit module to open, and the Buck circuit module to open.

[0133] S450, in the discharging stage, the battery charging and discharging control module controls the auxiliary Buck circuit module to open to transform the discharging voltage of the double-core battery into a voltage suitable for the system power supply module.

[0134] In the embodiments of the present disclosure, the battery charging and discharging control module controls other circuit modules to work or not to work to achieve charging and discharging control. Specifically, the battery charging and discharging control module can determine the port type of the AC / DC adapter to assist in determining the current threshold and the voltage threshold in the subsequent steps, and switch the charging and discharging stages; the battery charging and discharging control module collects the charging voltage and the charging current of the double-core battery in real time to determine whether the charging voltage is greater than the set voltage threshold and whether the charging current is greater than the set current threshold; if both are greater, the charge pump circuit module is controlled to open, large current charging can be performed, and the charging efficiency is higher and the heat is less; the battery charging and discharging control module also performs boost control protocol with the AC / DC adapter, and controls the AC / DC adapter to output dynamic voltage and dynamic current to the charge pump circuit module to charge the double-core battery; in the discharging stage, the battery charging and discharging control module controls the auxiliary Buck circuit module to step down the output voltage of the double-core battery to supply power to the system power supply module.

[0135] The embodiments of the present disclosure also provide a charging line comprising any of the above charging and discharging circuits.

[0136] Exemplarily, the above charging and discharging circuit can be arranged at one end of the charging line for connecting the double-core battery. In this way, a small current can flow through most of the wire of the charging line to reduce the heat on the wire and slow down the wear of the wire.

[0137] The embodiments of the present disclosure also provide a terminal device comprising a double-core battery, which is charged by any of the above charging and discharging circuits, or by any of the above charging and discharging methods, or based on any of the above charging lines to achieve the corresponding beneficial effects.

[0138] Exemplarily, the charge-discharge circuit can also be arranged in the terminal device, and the AC-DC adapter is connected through the charging line. At this time, the charging line is not provided with the charge-discharge circuit, and the structure of the charging line is simplified.

[0139] Exemplarily, the terminal device can be a mobile phone, a tablet, a mobile computer or other chargeable terminal device known to those skilled in the art, which is not limited herein.

[0140] It should be noted that, in this document, the terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0141] The above description is only a specific embodiment of the present disclosure, enabling those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A charge / discharge circuit with controllable step-up and step-down voltage, characterized in that, The application relates to a circuit for charging a double-cell battery, which comprises a Boost circuit module, a Buck circuit module, a charge pump circuit module, an auxiliary Buck circuit module, a battery charging and discharging control module and a system power supply module. The input end of the Boost circuit module, the input end of the Buck circuit module and the input end of the charge pump circuit module are respectively connected with an AC / DC adapter; the battery charging and discharging control module is connected with the controlled end of the Boost circuit module, the controlled end of the Buck circuit module, the controlled end of the charge pump circuit module, the double-cell battery and the controlled end of the auxiliary Buck circuit module; the output end of the Buck circuit module and the output end of the auxiliary Buck circuit module are respectively connected with the system power supply module; the output end of the Boost circuit module, the output end of the charge pump circuit module and the input end of the auxiliary Buck circuit module are respectively connected with the double-cell battery. The battery charging and discharging control module is a control module for controlling the Boost circuit module, the Buck circuit module, the charge pump circuit module and the auxiliary Buck circuit module to work in corresponding charging and discharging stages. The Boost circuit module works in a trickle charging stage, a constant voltage charging stage and a charging cutoff stage. The charge pump circuit module works in a constant current charging stage, and is a circuit module for making the output current of the charge pump circuit module greater than the input current and making the output voltage of the charge pump circuit module smaller than the input voltage. The Buck circuit module works in a constant current charging stage, a constant voltage charging stage and a charging cutoff stage, and is a circuit module for transforming the charging voltage into a voltage suitable for the system power supply module. The auxiliary Buck circuit module works in a discharging stage, and is a circuit module for transforming the discharging voltage of the double-cell battery into a voltage suitable for the system power supply module.

2. The circuit of claim 1, wherein, The charge pump circuit module comprises N charge pump circuit sub-modules which are arranged in parallel; N is an integer greater than or equal to 1. The controlled ends of the N charge pump circuit sub-modules are respectively connected with the battery charging and discharging control module.

3. The circuit of claim 1, wherein, The auxiliary Buck circuit module comprises a Buck circuit sub-module or a charge pump circuit sub-module.

4. The circuit of claim 3, wherein, The Buck circuit module and the Buck circuit sub-module both comprise a Buck controller, a first input capacitor, a first output capacitor, an output inductor and a first charging voltage and current controller, wherein the Buck controller comprises a first transistor and a second transistor. The first transistor and the second transistor are connected in series, the first input capacitor is connected with the first transistor, the first output capacitor is connected with the second transistor, the output inductor is connected with the second transistor and the first charging voltage and current controller, and the first charging voltage and current controller is connected with the first transistor. The battery information of the system power supply module is transmitted to the first charging voltage current controller, the first transistor and the output inductor are connected in series, the input end of the first transistor is used as the input end of the Buck step-down circuit module or the Buck step-down circuit submodule, the output end of the output inductor is used as the output end of the Buck step-down circuit module or the Buck step-down circuit submodule, the first input capacitor is connected in series between the input end of the first transistor and the ground, the first output capacitor is connected in series between the output end of the output inductor and the ground, one end of the second transistor is connected between the first transistor and the output inductor, and the other end is grounded; In the charging stage of the output inductor, the first transistor is turned on, and the second transistor is turned off; In the discharging stage of the output inductor, the first transistor is turned off, and the second transistor is turned on.

5. The circuit of claim 2 or 3, wherein, The charge pump circuit submodule comprises a first capacitor, a second capacitor, a third capacitor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor; The input end of the third transistor and one end of the third capacitor are connected and used as the input end of the charge pump circuit submodule, the other end of the third capacitor is grounded, the output end of the third transistor and the input end of the fourth transistor are connected to the first end of the first capacitor, the other end of the first capacitor is connected to the input end of the sixth transistor and the output end of the fifth transistor, the output end of the sixth transistor is grounded, the output end of the fourth transistor and the input end of the fifth transistor are connected to one end of the second capacitor and used as the output end of the charge pump circuit submodule, and the other end of the second capacitor is grounded; In the capacitor series connection stage, the third transistor and the fifth transistor are turned on, and the fourth transistor and the sixth transistor are turned off; In the capacitor parallel connection stage, the fourth transistor and the sixth transistor are turned on, and the third transistor and the fifth transistor are turned off.

6. The circuit of claim 2 or 3, wherein, The charge pump circuit submodule comprises a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, a seventh transistor, an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, a twelfth transistor and a thirteenth transistor; One end of the fourth capacitor and an input end of the seventh transistor are connected, and serve as an input end of the charge pump circuit sub-module, the other end of the fourth capacitor is grounded, an output end of the seventh transistor and an input end of the eighth transistor are connected with one end of the fifth capacitor, the other end of the fifth capacitor is connected with an input end of the ninth transistor and an input end of the tenth transistor, an output end of the ninth transistor and an output end of the thirteenth transistor are grounded, an input end of the thirteenth transistor and an output end of the twelfth transistor are connected with one end of the sixth capacitor, the other end of the sixth capacitor is connected with an output end of the tenth transistor and an output end of the eleventh transistor, an output end of the eighth transistor, an input end of the eleventh transistor and an input end of the twelfth transistor are connected with one end of the seventh capacitor, and serve as an output end of the charge pump circuit sub-module, the other end of the seventh capacitor is grounded; In the capacitor series connection stage, the seventh transistor, the tenth transistor and the twelfth transistor are turned on, and the eighth transistor, the ninth transistor, the eleventh transistor and the thirteenth transistor are turned off; In the capacitor parallel connection stage, the eighth transistor, the ninth transistor, the eleventh transistor and the thirteenth transistor are turned on, and the seventh transistor, the tenth transistor and the twelfth transistor are turned off.

7. The circuit of claim 1, wherein, The Boost circuit module comprises a Boost controller, a second input capacitor, a second output capacitor, an input inductor and a second charging voltage and current controller, and the Boost controller comprises a fourteenth transistor and a fifteenth transistor; The battery information of the double-cell battery is transmitted to the second charging voltage and current controller, the input inductor and the fourteenth transistor are connected in series between the AC / DC adapter and the double-cell battery, the second input capacitor is connected in series between an input end of the input inductor and the ground, the second output capacitor is connected in series between an output end of the fourteenth transistor and the ground, one end of the fifteenth transistor is connected between the fourteenth transistor and the input inductor, and the other end is grounded; In the input inductor charging stage, the fourteenth transistor is turned off, and the fifteenth transistor is turned on; In the input inductor discharging stage, the fourteenth transistor is turned on, and the fifteenth transistor is turned off.

8. A charge and discharge method capable of step-up and step-down control, characterized by, The charging and discharging circuit based on any one of claims 1-7 is executed, and the method comprises: The battery charging and discharging control module collects the charging voltage and the charging current of the double-cell battery in real time, and judges the charging and discharging stage of the double-cell battery based on the charging voltage and the charging current; In the trickle charging stage, the battery charging and discharging control module controls the Boost circuit module to be turned on to work; In the constant current charging phase, the battery charge and discharge control module controls the charge pump circuit module and the Buck step-down circuit module to be opened to work, so that the current output by the charge pump circuit module is greater than the input current, and the voltage output by the charge pump circuit module is less than the input voltage; In the constant voltage charging phase and the charging cutoff phase, the battery charge and discharge control module controls the charge pump circuit module to be closed, the Boost step-up circuit module to be opened, and the Buck step-down circuit module to be opened; In the discharging phase, the battery charge and discharge control module controls the auxiliary step-down circuit module to be opened to transform the discharging voltage of the double-cell battery into a voltage suitable for the system power supply module.

9. A charging cord, characterized in that The charge and discharge circuit comprises the charge and discharge circuit according to any one of claims 1-7.

10. A terminal device, comprising: The terminal device comprises a double-cell battery, which is charged by using the charge and discharge circuit according to any one of claims 1-7, or by using the charge and discharge method according to claim 8, or by using the charging line according to claim 9.

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