Charging system and method, and electronic device
By introducing a transformer circuit into the series charging system of multiple batteries in electronic devices, the power supply path to the load is increased and low-charge batteries are recharged, thus solving the problems of voltage drop and uneven charging during series charging and ensuring stable device performance and function.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- HUAWEI TECH CO LTD
- Filing Date
- 2025-06-27
- Publication Date
- 2026-07-02
AI Technical Summary
When multiple batteries in an electronic device are connected in series for charging, voltage drops can easily occur under heavy power supply conditions, affecting the user experience and device performance during charging.
By using a transformer circuit to increase the power supply path when the load voltage demand is high, and by using the transformer circuit and the second battery to supply power together, the system reduces the pump current from the low-side battery, and when necessary, the transformer circuit can supplement the low-charge battery to ensure balanced battery charging.
It effectively reduces voltage drops, ensures the performance and functional stability of the device in series charging scenarios, and improves the problem of uneven battery charging.
Smart Images
Figure CN2025104974_02072026_PF_FP_ABST
Abstract
Description
A charging system and method, and an electronic device
[0001] This application claims priority to Chinese Patent Application No. 202411457805.9, filed on October 17, 2024, entitled “A Charging System and Method, Electronic Device”, the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of electronic devices, and more particularly to a charging system and method, and an electronic device. Background Technology
[0003] With the widespread use of mobile phones, tablets and other electronic devices, the related technologies of electronic devices have also been rapidly improved. For example, the functions of mobile phones and other electronic devices are becoming more and more abundant, and users have higher demands for the battery life of electronic devices. As a result, the field of electronic devices has also developed related technologies such as multi-battery power supply.
[0004] For example, to improve the battery life of electronic devices, multiple batteries can be set up. These batteries can be charged in series and discharged in parallel. When charging, series charging can increase the charging voltage and multiply the charging power when the charging current is limited, without the need to add an additional step-down charging chip. When discharging, parallel discharge of multiple batteries has high power supply efficiency and strong power supply capacity.
[0005] However, these products have a clear disadvantage in scenarios where they are connected in series for charging and simultaneously supplied under high load, which can easily affect the user experience in charging scenarios. Summary of the Invention
[0006] This application provides a charging system and method, and an electronic device. When charging multiple batteries in series in an electronic device, a transformer circuit is used to increase the power supply to the load in the electronic device, thereby avoiding performance problems caused by large voltage drops in the batteries or low supply voltage when charging in series and supplying a large load at the same time.
[0007] To achieve the above objectives, the technical solution adopted in this application is as follows:
[0008] In a first aspect, a charging system is provided, including an input port, an output port, a first charging switch circuit, a transformer circuit, a charging control circuit, and a switching circuit. The input port is used to connect to an external power source, and the output port is used to connect to a load. The switching circuit is connected to a first battery and a second battery and is used to switch the connection relationship between the first battery and the second battery, the connection relationship including at least one of series or parallel connection. The first charging switch circuit is electrically connected to the input port and is also electrically connected to the first battery. When the first battery and the second battery are connected in series, the first charging switch circuit is used to receive electrical energy from an external power source through the input port to charge the series-connected first battery and the second battery, wherein the potential of the first battery is higher than the potential of the second battery. The charging control circuit is electrically connected to the first battery, the second battery, and the output port. When the first battery and the second battery are charged in series, the charging control circuit is used to connect the second battery to the output port, and the second battery discharges to the load through the output port. The transformer circuit is electrically connected to the input port to receive electrical energy from an external power source and is also electrically connected to the output port. If the voltage of the first battery is lower than a first threshold, the transformer circuit is used to supply power to the load through the output port.
[0009] In the series charging scenario, the charging system provided in this application embodiment is powered solely by the second battery. If the load voltage demand is high and the load drawdown is large, the transformer circuit is controlled to operate and supply power to the load. Thus, in the scenario of series charging of the first and second batteries, the power supply from the second battery alone is transformed into a power supply from the second battery and the transformer circuit jointly supplying power to the load. There are two power supply paths: the transformer circuit supplying power to the load and the second battery supplying power to the load. When the system drawdown current is large, the transformer circuit can provide some current to reduce the system drawdown current from the lower-side battery, thereby reducing the system power supply voltage drop and ensuring that the performance and function of electronic devices are not affected in the series charging scenario.
[0010] In one possible implementation, the system current output from the output port to the load is the sum of the current output from the second battery to the output port and the current output from the transformer circuit to the output port.
[0011] In one possible implementation, if the ratio of the charge level of the second battery to that of the first battery is lower than a second threshold, the transformer circuit is also used to charge the second battery through a charging control circuit. When the first and second batteries are charged in series, if the charge level of the second battery is lower and the charge level of the first battery is higher, to prevent uneven charging between the first and second batteries, the transformer circuit can be used to increase the charging of the second battery. This increases the charging current of the second battery, improves its charging speed, and alleviates the problem of uneven charging between the first and second batteries.
[0012] In one possible implementation, the charging current of the second battery is the sum of the charging current of the first battery and the current output to the first battery by the transformer circuit.
[0013] In one possible implementation, the switching circuit includes a first switching circuit, a second switching circuit, and a third switching circuit. The first switching circuit is connected between the negative terminal of the first battery and the common ground, the second switching circuit is connected between the negative terminal of the first battery and the positive terminal of the second battery, and the third switching circuit is connected between the positive terminal of the first battery and the positive terminal of the second battery. If the first and third switching circuits are turned on and the second switching circuit is turned off, the connection between the first and second batteries is switched to parallel. If the first and third switching circuits are turned off and the second switching circuit is turned on, the connection between the first and second batteries is switched to series.
[0014] In one possible implementation, the charging system further includes a control unit, which controls the conduction states of the first switching circuit, the second switching circuit, and the third switching circuit to switch the connection relationship between the first battery and the second battery.
[0015] In one possible implementation, if the switching circuit switches the connection between the first battery and the second battery to parallel connection, the charging control circuit is also used to connect the first battery to the output port and the second battery to the output port. The first battery and the second battery are connected in parallel and discharge to the load through the output port. The first battery and the second battery can discharge to the load in parallel, which can improve power supply efficiency and enhance power supply capacity.
[0016] In one possible implementation, the charging control circuit includes a fourth switch circuit and a fifth switch circuit. The first terminal of the fourth switch circuit and the first terminal of the fifth switch circuit are connected to the output port. The second terminal of the fifth switch circuit is connected to the positive terminal of the first battery, and the second terminal of the fourth switch circuit is connected to the positive terminal of the second battery. If the first terminal and the second terminal of the fifth switch circuit are connected, the first battery is connected to the output port. If the first terminal and the second terminal of the fourth switch circuit are connected, the second battery is connected to the output port.
[0017] In one possible implementation, the charging system further includes a control unit for controlling the conduction states of the fourth and fifth switching circuits to control the conduction states of the first battery, the second battery, and the output port.
[0018] In one possible implementation, the charging system further includes a second charging switch circuit, through which the transformer circuit is electrically connected to the input port; the second charging switch circuit is used to switch the conduction state of the transformer circuit and the input port, thereby controlling the operating state of the transformer circuit.
[0019] Secondly, a charging method is provided, comprising: a first charging switch circuit of a charging system, when the first battery and the second battery are connected in series, receiving electrical energy from an external power source through the input port of the charging system to charge the first battery and the second battery connected in series, wherein the potential of the first battery is higher than the potential of the second battery; a charging control circuit of the charging system connects the second battery to the output port of the charging system, and the second battery discharges to the load through the output port; if the voltage of the first battery is lower than a first threshold, the transformer circuit of the charging system supplies power to the load through the output port.
[0020] In one possible implementation, the method further includes: if the state of charge of the second battery is lower than a second threshold, the transformer circuit charges the second battery through the charging control circuit.
[0021] Thirdly, an electronic device is provided, comprising a first battery, a second battery, and a charging system as provided in the first aspect and any implementation thereof, the charging system being electrically connected to the first battery and the second battery. Attached Figure Description
[0022] Figure 1 is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;
[0023] Figure 2 is a schematic diagram of a foldable screen mobile phone provided in an embodiment of this application;
[0024] Figure 3 is a schematic diagram of a charging system provided in an embodiment of this application;
[0025] Figure 4 is a schematic diagram of a series charging scenario of the charging system provided in the embodiment of this application;
[0026] Figure 5 is a schematic diagram of a parallel power supply scenario for the charging system provided in an embodiment of this application;
[0027] Figure 6 is a schematic diagram of the power supply to the load in a series charging scenario of the charging system provided in the embodiment of this application;
[0028] Figure 7 is a schematic diagram of the current flow in a series charging scenario of the charging system provided in the embodiment of this application;
[0029] Figure 8 is a schematic diagram of another current flow direction in the series charging scenario of the charging system provided in the embodiment of this application. Detailed Implementation
[0030] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0031] Hereinafter, the terms "first," "second," etc., are used for descriptive convenience only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more. For example, multiple processing units refer to two or more processing units.
[0032] In the embodiments of this application, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. In addition, the term "electrical connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium.
[0033] In this application, the term "unit" typically refers to a logically divided functional structure. This "unit" can be implemented purely in hardware, or a combination of hardware and software. In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, or both A and B existing simultaneously.
[0034] In this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being better or more advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.
[0035] The charging system provided in this application embodiment can be applied to electronic devices, such as mobile phones, tablets, personal digital assistants (PDAs), virtual reality (VR) electronic devices, augmented reality (AR) electronic devices, etc.
[0036] The following description uses a mobile phone as an example. Figure 1 shows a schematic diagram of the structure of an electronic device provided in this application. Referring to Figure 1, the electronic device may include: a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (USB) interface 130, a charging system 140, a power management module 141, a battery 142, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, a headphone jack 170D, a sensor 180, buttons 190, a motor 191, an indicator 192, a camera 193, a display module 194, and a subscriber identification module (SIM) card interface 195, etc.
[0037] The structure illustrated in this embodiment does not constitute a specific limitation on the electronic device. In other embodiments, the electronic device may include more or fewer components than illustrated, or combine some components, or split some components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.
[0038] It is understood that the interface connection relationships between the modules illustrated in this embodiment are merely illustrative and do not constitute a structural limitation on the electronic device. In other embodiments, the electronic device may also employ different interface connection methods or combinations of multiple interface connection methods as described in the above embodiments.
[0039] To avoid redundancy, this application only describes the content relevant to this solution; the functions and principles of other functional devices or structures of the electronic device are not repeated. The charging system 140 is used to receive electrical energy input from the charger. While charging the battery 142, the charging system 140 can also supply power to other loads of the electronic device, including electrical components in the electronic device, such as the processor 110, audio module 170, camera 193, display module 194, and other functional components.
[0040] As mobile phones become increasingly feature-rich and widely used, various types of mobile phones have gradually emerged, such as foldable phones. Foldable screen phones have larger screens, as shown in Figure 2. Figure 2 shows a schematic diagram of a double-folding foldable screen phone, where the display screen can fold along the bending axis. Figure 2a shows a schematic diagram of the foldable screen phone in its unfolded state, and Figure 2b shows a schematic diagram of the foldable screen phone in its partially folded state. The foldable screen phone shown in Figure 2 folds along the long side, but it can also be a foldable screen phone that folds along the short side, or it can be a triple-folding screen phone or other forms of foldable screen phones. Foldable screen phones have more body space and can also accommodate more batteries to power the load. Other electronic devices, such as tablets, can also have multiple batteries to power the load.
[0041] In this type of electronic device that uses multiple batteries for power supply / charging, the connection relationship of the multiple batteries is fixed. During charging, the multiple batteries are connected in series to charge; during discharging, the multiple batteries are connected in parallel to discharge.
[0042] For example, referring to Figure 3, Figure 3 shows a schematic diagram of a charging system provided in an embodiment of this application. The charging system includes an input port VIN, an output port VOUT, a first charging switch circuit 210, a second charging switch circuit 220, a switching circuit (not shown in the figure), a charging control circuit 240, and a transformer circuit 250. The input port VIN is used to connect to an external power source, and the output port VOUT is used to connect to a load.
[0043] The switching circuit is connected to multiple batteries and is used to switch the connection relationship of the batteries, such as series or parallel connection. In this embodiment, taking a first battery and a second battery as an example, the switching circuit includes a first switching circuit 231, a second switching circuit 232, and a third switching circuit 233. The first switching circuit 231 is located between the negative terminal of the first battery and the common ground (GND), the second switching circuit 232 is located between the negative terminal of the first battery and the positive terminal of the second battery, and the third switching circuit 233 is located between the positive terminals of the first and second batteries. By switching the conduction states of the first switching circuit 231, the second switching circuit 232, and the third switching circuit 233, the connection relationship of the first and second batteries can be switched. For example, if the first switching circuit 231 and the third switching circuit 233 are on, and the second switching circuit 232 is off, the first and second batteries are in parallel connection; if the second switching circuit 232 is on, and the first switching circuit 231 and the third switching circuit 233 are off, the first and second batteries are in series connection.
[0044] The charging control circuit 240 is electrically connected to the first battery, the second battery, and the output port VOUT, and is used to switch the connection state of the first battery, the second battery, and the output port VOUT. For example, the charging control circuit 240 includes a fourth switch circuit 241 and a fifth switch circuit 242. The first end of the fourth switch circuit 241 is connected to the output port VOUT, and the second end of the fourth switch circuit 241 is connected to the positive terminal of the second battery. The first end of the fifth switch circuit 242 is connected to the output port VOUT, and the second end of the fifth switch circuit 242 is connected to the positive terminal of the first battery. If the first end and the second end of the fourth switch circuit 241 are connected, the second battery is connected to the output port VOUT. If the first end and the second end of the fifth switch circuit 242 are connected, the first battery is connected to the output port VOUT.
[0045] A first charging switch circuit 210 is connected between the input port VIN and the positive terminal of the first battery. When the first and second batteries are connected in series, the first charging switch circuit 210 controls the input port VIN to receive electrical energy from an external power source to charge the series-connected first and second batteries. For example, the first charging switch circuit 210 includes a third transistor Q3, with its first terminal connected to the input port VIN and its second terminal connected to the positive terminal of the first battery.
[0046] A transformer circuit 250 is connected between the input port VIN and the output port VOUT for charging the battery or load. The transformer circuit 250 can be, for example, a boost-buck converter circuit or a buck converter circuit. Typically, the external power input to the charging system cannot directly power the load or charge the battery. The transformer circuit 250 adjusts the external input voltage or current signal, converting it into a voltage or current signal that can directly power the load or meet the battery charging requirements. The transformer circuit 250 can be connected to the first or second battery via the charging control circuit 240. For example, the transformer circuit 250 can be connected to the second battery via the fourth switch circuit 241 or to the first battery via the fifth switch circuit 242 to charge the first or second battery.
[0047] In one possible implementation, the transformer circuit 250 is electrically connected to the input port VIN via the second charging switch circuit 220. By controlling the conduction state of the second charging switch circuit 220, the operating state of the transformer circuit 250 can be controlled. When the second charging switch circuit 220 is on, the transformer circuit 250 is powered on and running. When the second charging switch circuit 220 is off, the transformer circuit 250 is not working.
[0048] For example, the second charging switch circuit 220 includes a fourth transistor Q4. The first terminal of the fourth transistor Q4 is electrically connected to the input port VIN, and the second terminal of the fourth transistor Q4 is electrically connected to the transformer circuit 250. When the first terminal and the second terminal of the fourth transistor Q4 are turned on, the transformer circuit 250 is powered on and operates. When the first terminal and the second terminal of the fourth transistor Q4 are turned off, the transformer circuit 250 does not work.
[0049] For example, the charging system also includes a control unit (not shown), which controls the conduction state of various switching circuits in the charging system to control the operation of the charging system. For instance, the control unit controls the conduction state of the first switching circuit 231, the second switching circuit 232, and the third switching circuit 233 to switch the connection relationship between the first battery and the second battery. The control unit also controls the conduction state of the fourth switching circuit 241 and the fifth switching circuit 242 to control the conduction state of the first battery, the second battery, and the output port VOUT. In addition, the control unit also controls the conduction state of the first charging switching circuit 210 and the second charging switching circuit 220 to switch the operating state of the charging system.
[0050] Typically, external power supply can refer to the power provided by a charging adapter connected to the power grid. When the electronic device and the charging adapter complete the charging protocol interaction, and the charging adapter can provide a higher voltage, the first battery and the second battery can be charged through the first charging switch circuit 210. If the electronic device cannot complete the charging protocol interaction with the charging adapter, and the charging adapter can only provide a lower voltage (e.g., 5V), then the voltage needs to be transformed by the transformer circuit 250 to supply power to the load or to charge the first battery and the second battery.
[0051] Based on the above charging system, when charging the first and second batteries, series charging can increase the charging voltage, multiplying the charging power under limited charging current, without the need for additional step-down charging chips. During discharge, the first and second batteries can discharge in parallel, resulting in high power supply efficiency and strong power supply capacity.
[0052] The basic principles of series charging and parallel power supply of the charging system provided in the embodiments of this application are described below with reference to the accompanying drawings.
[0053] First, the principle of series charging is introduced with reference to Figure 4. Figure 4 is a schematic diagram of the series charging scenario of the charging system provided in the embodiment of this application. During series charging, the first switch circuit 231 and the third switch circuit 233 are disconnected, and the second switch circuit 232 is turned on. The switching circuit switches the connection relationship of the first battery and the second battery to series. The first charging switch circuit 210 is turned on, the second charging switch circuit 220 is disconnected, the fourth switch circuit 241 is turned on, and the fifth switch circuit 242 is disconnected. The charging current loop is as follows: it passes through the input port VIN, the first charging switch circuit 210, the first battery, the second switch circuit 232, and the second battery to the common ground in sequence, thereby forming a charging loop. The electrical energy received by the input port VIN is used to charge the first battery and the second battery in series. In series charging, since the first and second batteries are connected in series, if the voltage of the second battery is Vbat, then the voltage of the first battery is higher than that of the second battery, which can be approximated as 2Vbat. The second battery with the lower voltage is usually called the low-side battery, and the first battery with the higher voltage is called the high-side battery. It can be seen that series charging can increase the charging voltage and increase the charging power when the charging current is limited.
[0054] The principle of parallel power supply is explained below with reference to Figure 5. In parallel power supply, the first switch circuit 231 and the third switch circuit 233 are turned on, while the second switch circuit 232 is turned off. The switching circuit switches the connection between the first and second batteries to parallel. The first charging switch circuit 210 and the second charging switch circuit 220 are turned off, while the fourth switch circuit 241 and the fifth switch circuit 242 are both turned on. The charging control circuit 240 connects the first battery to the output port VOUT and the second battery to the output port VOUT. At this time, the first and second batteries are connected in parallel to supply power to the load. The power supply current loop for the first battery is as follows: through the positive terminal of the first battery, sequentially through the fifth switch circuit 242, the output port VOUT, the load, and the device common ground to the negative terminal of the first battery, forming a discharge loop. The power supply current loop for the second battery is as follows: through the positive terminal of the second battery, sequentially through the fourth switch circuit 241, the output port VOUT, the load, and the device common ground to the negative terminal of the second battery, forming a discharge loop. Parallel discharge of the first and second batteries can improve power supply efficiency and enhance the power supply capability to the load in electronic equipment.
[0055] However, in series charging scenarios, since the voltage of the first battery is relatively high, such as 2Vbat, only the second battery can supply power to the load. In this case, the voltage drop during system load shedding is greater than that in the scenario of dual-battery parallel power supply when not charging. The voltage drop caused by the battery internal resistance and power supply line impedance is more severe than that in conventional parallel power supply, which can lead to performance or even functional problems caused by the low system power supply voltage, affecting the user experience.
[0056] To improve this problem, refer to Figure 6, which is a schematic diagram of the series charging scenario of the charging system provided in the embodiment of this application to supply power to the load. The charging system provided in the embodiment of this application can use the transformer circuit 250 to increase the power supply to the load, reduce the load current drawn from the second battery, thereby reducing the voltage drop of the system power supply and avoiding affecting the normal operation of electronic equipment.
[0057] For example, in a series charging scenario, the voltage supplied by the charging adapter to the input port VIN of the charging system is relatively high. The transformer circuit 250 can step down the voltage supplied by the input port VIN. For example, the transformer circuit 250 can be a BUCK step-down circuit. The transformer circuit 250 transforms the voltage obtained from the input port VIN into Bat_L + ΔV and supplies power to the load through the output port VOUT. Here, Bat_L is the output voltage of the second battery supplying power to the load, and ΔV can be set according to the load requirements. By adding the transformer circuit 250 to supply power to the load, in the scenario of series charging of the first and second batteries, the power supply from the second battery alone is changed to the power supply from the second battery and the transformer circuit 250 jointly supplying power to the load. Referring to Figure 6, in this case, there are two power supply paths in the charging system. Power supply path 1 is the power supply path for the second battery. The supply current flows from the second battery through the fourth switch circuit 241, the output port VOUT, the load, and forms a loop to the common ground. In this case, the fourth switch circuit 241 operates in a unidirectional conduction state, that is, the current can flow from the second battery to the output port VOUT.
[0058] Power supply path 2 is the power supply path for transformer circuit 250. The power supply current flows from the input port through the second charging switch circuit 220, transformer circuit 250, output port VOUT, and load to the common ground to form a loop. At this time, the system current output from output port VOUT to the load is the sum of the current output from the second battery to the output port and the current output from transformer circuit 250 to the output port. With these two power supply paths, when the system drawdown current is large, transformer circuit 250 can provide some current to reduce the system drawdown current from the low-side battery, thereby reducing the system power supply voltage drop.
[0059] In one possible implementation, the transformer circuit 250 can supply power to the load through its output port VOUT when the voltage of the first battery is lower than a first threshold. For example, when the processor of an electronic device has a large computational load, the load is large. If the load is too large and causes the voltage of the first battery to fall below the first threshold, the second charging switch circuit 220 is turned on, and the transformer circuit 250 is operated to increase the power supply of the transformer circuit 250 to the load. The first threshold can be set according to the performance of the first battery.
[0060] By adding a transformer circuit 250 to supply power to the load in scenarios with large load withdrawal, the transformer circuit 250 and the second battery can jointly bear the system load withdrawal under large load conditions, reducing the withdrawal current from the second battery and reducing the voltage drop of the load supply, thus ensuring that the performance and function of electronic devices are not affected in series charging scenarios.
[0061] In series charging scenarios, besides the problem of large voltage drops, there are also issues such as uneven charging. Please refer to Figure 7, which is a schematic diagram of the current flow in a series charging scenario of the charging system provided in this embodiment. Since the first battery has a higher potential in the series charging scenario, the load is powered only by the second battery. At this time, the charging current of the battery satisfies: i_chg_batH=i_chg_batL+i_sys
[0062] In the above formula, i_chg_batH represents the charging current of the first battery, i_chg_batL represents the charging current of the second battery, and i_sys represents the current supplied by the battery to the load. As can be seen from the formula, the charging current of the first battery is greater than that of the second battery. This leads to an imbalance in the charging of the first and second batteries, meaning the first battery charges faster and the second battery charges slower. In this situation, if the first battery is rapidly charged to a higher charge level, its charging current will gradually decrease. Since the first and second batteries are charged in series, the decrease in the charging current of the first battery will also lead to a decrease in the charging current of the second battery, further slowing down the charging speed of the second battery. This exacerbates the charging imbalance between the first and second batteries.
[0063] To improve this problem, the charging system provided in this application embodiment can increase the charging of the second battery by using a transformer circuit 250 when the first battery and the second battery are charged in series. When the second battery is charged in series with the first battery, the transformer circuit 250 also charges the second battery, thereby increasing the charging current of the second battery, improving the charging speed of the second battery, and improving the problem of uneven charging between the first battery and the second battery.
[0064] Referring to Figure 8, which is a schematic diagram of another current flow in a series charging scenario of the charging system provided in this application embodiment, there are two charging paths. One charging path is the series charging of the first battery and the second battery. The charging current passes through the input port VIN, the first charging switch circuit 210, the first battery, the second switch circuit 232, the second battery, and the common ground to form a charging loop, simultaneously charging both the first and second batteries. The other charging path is the charging of the second battery by the transformer circuit 250. The charging current passes through the input port VIN, the second charging switch circuit 220, the transformer circuit 250, the fourth switch circuit 241, the second battery, and the ground to form a charging loop, charging the second battery and increasing its charging speed.
[0065] In this case, the charging current of the second battery satisfies: i_chg_batL=i_chg_batH+i_chg_buck
[0066] In the above formula, i_chg_batL is the charging current of the second battery, i_chg_batH is the charging current of the first battery, and i_chg_buck is the charging current of the transformer circuit 250 to the second battery. In this case, the fourth switching circuit 241 operates in a bidirectional conduction state. Current can flow from the second battery through the fourth switching circuit 241 to the output port VOUT, and the second battery supplies power to the load; or the current can also flow from the transformer circuit 250 through the fourth switching circuit 241 to the second battery to replenish the second battery and improve its charging efficiency. The charging current provided by the input port is relatively stable, while the discharge current of the load fluctuates greatly. Usually, the load current is less than the charging current of the port during charging, but there will be instantaneous situations where the large load exceeds the port charging current. That is to say, the average value of the load current is less than the charging current, but the peak value is greater than the charging current. Charging is a continuous process, and the average value of i_chg_buck is larger, so it can play a role in replenishing the load.
[0067] As can be seen from the above formula, when the transformer circuit 250 is added to charge the second battery, the charging current of the second battery is greater than that of the first battery, which can improve the problem of uneven charging between the first and second batteries in the series charging scenario.
[0068] In one possible implementation, when the ratio of the charge of the second battery to the charge of the first battery is lower than a second threshold, the transformer circuit 250 charges the second battery through the charging control circuit 240. For example, the second threshold can be set according to the charging speed of the second battery. If the charge of the second battery is low and the charge of the first battery is high, the second charging switch circuit 220 is turned on to control the operation of the transformer circuit 250 and turn on the fourth switch circuit 241. The transformer circuit 250 is connected to the second battery through the fourth switch circuit 241 to charge the second battery.
[0069] The charging system provided in this application addresses the issue that the charging current of the low-side battery is less than that of the high-side battery in a series charging scenario by adding a low-side battery charging path, which can achieve balanced charging of multiple battery groups in a series charging scenario.
[0070] In the embodiments of this application, the switching circuit, etc., may include circuits composed of transistors or transistors. The transistors may be metal-oxide-semiconductor field-effect transistors (MOSFETs) or other types of transistors, and the embodiments of this application are not limited thereto. For example, the fourth switching circuit 241 and the fifth switching circuit 242 may be battery field-effect transistors (BATFETs) that control the battery charging path. Taking the fourth switching circuit 241 as an example, based on the different voltages applied to the BATFET, the BATFET can be controlled to operate in different states, such as the off state, the unidirectional conduction state, or the bidirectional conduction state.
[0071] This application also provides a charging method, including:
[0072] S10: When the first battery and the second battery are connected in series, the first charging switch circuit of the charging system receives electrical energy from an external power source through the input port of the charging system to charge the first battery and the second battery connected in series, wherein the potential of the first battery is higher than that of the second battery.
[0073] S20: The charging control circuit of the charging system connects the second battery to the output port of the charging system, and the second battery discharges to the load through the output port.
[0074] Under normal circumstances, during series charging, since the first and second batteries are connected in series, the voltage of the first battery is higher than that of the second battery, and only the second battery supplies power to the load.
[0075] S30: The transformer circuit of the charging system supplies power to the load through the output port.
[0076] In series charging scenarios, because the voltage of the first battery is relatively high, for example, 2Vbat, only the second battery can supply power to the load. In this case, the voltage drop during system load shedding is greater than in the parallel power supply scenario of dual batteries when not charging. The voltage drop caused by the battery's internal resistance and the power supply line impedance is more severe than in conventional parallel power supply, resulting in performance and even functional problems due to excessively low system supply voltage, affecting the user experience. The charging system provided in this application embodiment supplies power to the load through the output port VOUT using a transformer circuit when the voltage of the second battery is lower than a first threshold. For example, when the processor of an electronic device has a large computational load, the voltage requirement is large, and the load shedding is also large. If the load shedding is too large, causing the voltage of the second battery to fall below the first threshold, the second charging switch circuit is activated, and the transformer circuit is controlled to operate, increasing the power supply of the transformer circuit to the load. The first threshold can be set according to the performance of the first battery. By adding a transformer circuit to supply power to the load in scenarios with large load drawdown, the transformer circuit and the second battery can jointly bear the system drawdown when the load demand voltage is large and the drawdown is large. This reduces the drawdown current from the second battery and reduces the voltage drop of the load supply, ensuring that the performance and function of electronic devices are not affected in series charging scenarios.
[0077] In one possible implementation, the method further includes:
[0078] S40: The transformer circuit charges the second battery through the charging control circuit.
[0079] In a series charging scenario, the charging current of the first battery is greater than that of the second battery. This leads to an imbalance in the charging speed between the two batteries, meaning the first battery charges faster and the second battery charges slower. In this situation, if the first battery is rapidly charged to a higher level, its charging current will gradually decrease. Since the first and second batteries are charged in series, this decrease in the first battery's charging current will also lead to a decrease in the second battery's charging current, further slowing down its charging speed and exacerbating the charging imbalance between the two batteries.
[0080] To improve this problem, the charging system provided in this application embodiment can increase the charging of the second battery by using a transformer circuit when the first battery and the second battery are charged in series. When the second battery is charged in series with the first battery, the transformer circuit also charges the second battery. This increases the charging current of the second battery, improves the charging speed of the second battery, and improves the problem of uneven charging between the first battery and the second battery.
[0081] For example, if the ratio of the charge of the second battery to the charge of the first battery is lower than a second threshold, when the first and second batteries are charged in series, a transformer circuit can be used to increase the charging of the second battery, improve the charging speed of the second battery, and improve the problem of uneven charging between the first and second batteries.
[0082] This application also provides an electronic device, such as the electronic device shown in Figures 1 and 2 above. The electronic device includes a charging system as provided in the above embodiments and multiple batteries, such as a first battery and a second battery. The charging system is electrically connected to the first battery and the second battery and is used to control the charging and discharging of the first battery and the second battery.
[0083] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A charging system, characterized in that, It includes an input port, an output port, a first charging switch circuit, a transformer circuit, a charging control circuit, and a switching circuit. The input port is used to connect to an external power source, and the output port is used to connect to a load. The switching circuit is connected to the first battery and the second battery and is used to switch the connection relationship between the first battery and the second battery. The connection relationship includes at least one of series or parallel connection. The first charging switch circuit is electrically connected to the input port and is also electrically connected to the first battery. The first charging switch circuit is used to receive electrical energy from an external power source through the input port to charge the first battery and the second battery connected in series when the first battery and the second battery are connected in series, wherein the potential of the first battery is higher than the potential of the second battery. The charging control circuit is electrically connected to the first battery, the second battery and the output port. The charging control circuit is used to connect the second battery to the output port when the first battery and the second battery are charged in series. The second battery discharges to the load through the output port. The transformer circuit is electrically connected to the input port to receive electrical energy from an external power source, and is also electrically connected to the output port for supplying power to the load through the output port.
2. The charging system according to claim 1, characterized in that, The system current output from the output port to the load is the sum of the current output from the second battery to the output port and the current output from the transformer circuit to the output port.
3. The charging system according to claim 1 or 2, characterized in that, The transformer circuit is also used to charge the second battery via the charging control circuit.
4. The charging system according to claim 3, characterized in that, The charging current of the second battery is the sum of the charging current of the first battery and the current output by the transformer circuit to the first battery.
5. The charging system according to any one of claims 1 to 4, characterized in that, If the switching circuit switches the connection relationship of the first battery and the second battery to parallel connection, the charging control circuit is also used to connect the first battery to the output port and the second battery to the output port, so that the first battery and the second battery are connected in parallel and the load is discharged through the output port.
6. The charging system according to any one of claims 1 to 5, characterized in that, The switching circuit includes a first switching circuit, a second switching circuit, and a third switching circuit. The first switching circuit is connected between the negative terminal of the first battery and the common ground. The second switching circuit is connected between the negative terminal of the first battery and the positive terminal of the second battery. The third switching circuit is connected between the positive terminal of the first battery and the positive terminal of the second battery. If the first switching circuit and the third switching circuit are turned on and the second switching circuit is turned off, the connection relationship between the first battery and the second battery is switched to parallel connection. If the first switch circuit and the third switch circuit are disconnected and the second switch circuit is turned on, the connection relationship between the first battery and the second battery is switched to series connection.
7. The charging system according to claim 6, characterized in that, The charging system also includes a control unit, which is used to control the conduction state of the first switching circuit, the second switching circuit and the third switching circuit, so as to switch the connection relationship between the first battery and the second battery.
8. The charging system according to any one of claims 1 to 5, characterized in that, The charging control circuit includes a fourth switch circuit and a fifth switch circuit. The first terminal of the fourth switch circuit and the first terminal of the fifth switch circuit are connected to the output port. The second terminal of the fifth switch circuit is connected to the positive terminal of the first battery, and the second terminal of the fourth switch circuit is connected to the positive terminal of the second battery. If the first and second terminals of the fifth switching circuit are connected, the first battery is connected to the output port. If the first and second terminals of the fourth switching circuit are connected, the second battery is connected to the output port.
9. The charging system according to claim 8, characterized in that, The charging system also includes a control unit, which controls the conduction state of the fourth switch circuit and the fifth switch circuit to control the conduction state of the first battery, the second battery and the output port.
10. The charging system according to any one of claims 1 to 9, characterized in that, The charging system further includes a second charging switch circuit, and the transformer circuit is electrically connected to the input port through the second charging switch circuit. The second charging switch circuit is used to switch the conduction state between the transformer circuit and the input port.
11. An electronic device, characterized in that, It includes a first battery, a second battery, and a charging system as described in any one of claims 1 to 10, wherein the charging system is electrically connected to the first battery and the second battery.
12. A charging method, characterized in that, The method includes: When the first battery and the second battery are connected in series, the first charging switch circuit of the charging system receives electrical energy from an external power source through the input port of the charging system to charge the first battery and the second battery connected in series, wherein the potential of the first battery is higher than that of the second battery. The charging control circuit of the charging system connects the second battery to the output port of the charging system, and the second battery discharges to the load through the output port. The transformer circuit of the charging system supplies power to the load through the output port.
13. The method according to claim 12, characterized in that, The method further includes: The transformer circuit charges the second battery through the charging control circuit.