Direct-current voltage converter, control method therefor, chip and electronic device

Abstract

This application provides a DC-DC converter and its control method, chip, and electronic device, including a switched capacitor circuit, an equalization circuit, and a control unit. It reuses an existing switched capacitor circuit while integrating an equalization circuit. When the voltages of the first and second battery cells are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switching transistor in the switched capacitor circuit. This controls the equalization current between the first and second battery cells, achieving voltage equalization of the battery pack. Based on this, efficient active battery equalization can be achieved while reducing hardware costs and size. This not only avoids the energy dissipation losses of passive equalization but also reduces the additional losses caused by adding a separate power circuit for the equalization function, thereby significantly improving the usable capacity and overall lifespan of the battery pack.

Description

Technical Field

[0001] This application relates to the field of power supply, and more particularly to a DC voltage converter and its control method, chip, and electronic device. Background Technology

[0002] For example, in high-performance devices such as laptops and tablets, battery packs typically use a multi-cell series connection architecture to meet system power requirements. Meanwhile, some loads within these devices require a stable, lower operating voltage.

[0003] In practical applications, due to initial differences in battery cells, uneven temperature distribution during use, and different aging rates, the voltage, capacity, and internal resistance of individual cells in a series-connected battery pack will be inconsistent, resulting in an "imbalance" phenomenon. This phenomenon causes the battery with the highest or lowest voltage to reach the protection threshold first during charging and discharging, forcing the entire battery pack to stop working prematurely. This severely reduces the usable capacity of the battery pack and the device's battery life, and accelerates the overall aging of the battery pack.

[0004] Therefore, battery power balancing is necessary. Current passive balancing technology requires separate power devices such as inductors, capacitors, and switching transistors for the balancing function, which increases the system's material cost, footprint, and wiring complexity. Furthermore, the added circuitry generates significant losses. Summary of the Invention

[0005] This application provides a DC voltage converter and its control method, chip, and electronic device, which achieves efficient active battery balancing while reducing the increase in hardware cost and size.

[0006] In a first aspect, embodiments of this application provide a DC-DC voltage converter, comprising:

[0007] A switched capacitor circuit, the first terminal of which is connected to a battery pack, the battery pack including a first battery cell and a second battery cell connected in series, the switched capacitor circuit having an intermediate node.

[0008] An equalization circuit, the first end of which is connected to the connection node between the first battery cell and the second battery cell, and the second end of which is connected to the intermediate node;

[0009] The control unit is connected to the control terminals of each switching transistor in the switched capacitor circuit.

[0010] The control unit is configured to: when the absolute value of the voltage difference between the first battery cell and the second battery cell is greater than a preset threshold, modulate the voltage of the intermediate node by adjusting the duty cycle of the switching transistor in the switched capacitor circuit, so as to control the equalization current of the equalization circuit between the first battery cell and the second battery cell, thereby achieving voltage equalization of the battery pack.

[0011] Optionally, the equalization circuit includes:

[0012] A switching unit, the first terminal of which serves as the first terminal of the equalization circuit;

[0013] An energy storage unit, the first end of which serves as the second end of the equalization circuit, and the second end of which is connected to the second end of the switching unit;

[0014] The control unit is configured to control the switching unit to be in an on state during equalization to generate the equalization current in the energy storage unit.

[0015] Optionally, the energy storage unit includes: an inductor;

[0016] The switching unit includes a switching transistor.

[0017] Optionally, the switched capacitor circuit includes:

[0018] The first bridge arm unit, when its first end serves as the first end of the switched capacitor circuit, its second end serves as the second end of the switched capacitor circuit; when its first end serves as the second end of the switched capacitor circuit, its second end serves as the first end of the switched capacitor circuit; its third end is grounded.

[0019] The second bridge arm unit has a first end connected to the first end of the first bridge arm unit, a second end connected to the second end of the second bridge arm unit, and a third end grounded.

[0020] The first flying capacitor has its first end connected to the fourth end of the first bridge arm unit and its second end connected to the fifth end of the first bridge arm unit; the connection point between the second end of the first flying capacitor and the fifth end of the first bridge arm unit forms a first intermediate node.

[0021] The second flying capacitor has its first end connected to the fourth end of the second bridge arm unit and its second end connected to the fifth end of the second bridge arm unit; the connection point between the second end of the second flying capacitor and the fifth end of the second bridge arm unit forms a second intermediate node.

[0022] Optionally, the first bridge arm unit includes:

[0023] Four cascaded switching transistors are used. The first end of the first switching transistor serves as the first end of the first bridge arm unit; the connection end of the first two switching transistors serves as the fourth end of the first bridge arm unit; the connection end of the middle two switching transistors serves as the third end of the first bridge arm unit; the connection end of the last two switching transistors serves as the fifth end of the first bridge arm unit; and the second end of the last switching transistor serves as the second end of the first bridge arm unit.

[0024] The second bridge arm unit includes:

[0025] Four cascaded switching transistors are used. The first end of the first switching transistor serves as the first end of the second bridge arm unit; the connection end of the first two switching transistors serves as the fourth end of the second bridge arm unit; the connection end of the middle two switching transistors serves as the third end of the second bridge arm unit; the connection end of the last two switching transistors serves as the fifth end of the second bridge arm unit; and the second end of the last switching transistor serves as the second end of the second bridge arm unit.

[0026] Optionally, the DC-DC converter has a first operating mode and a second operating mode;

[0027] In the first operating mode, the switched capacitor circuit operates to perform step-down conversion;

[0028] In the second operating mode, the switched capacitor circuit and the equalization circuit work together to perform step-down conversion while transferring energy between different battery cells in the battery pack based on the equalization circuit, so as to achieve battery equalization.

[0029] Optionally, the second battery cell is grounded;

[0030] In the second operating mode, the DC-DC converter operates in a multi-phase interleaved manner, which includes at least a first-phase power stage and a second-phase power stage;

[0031] Each power stage's duty cycle includes at least two switching modes, where:

[0032] In the first switching mode, the switching unit in the equalization circuit is turned on, and the first set of switching transistors in the switched capacitor circuit is turned on, so that the voltage across the energy storage unit in the equalization circuit is the difference between the voltage of the second battery unit and the voltage at the output of the switched capacitor circuit, and the current in the energy storage unit changes in the positive direction.

[0033] In the second switching mode, the switching unit is turned on, and the second set of switching transistors in the switched capacitor circuit is turned on, so that the voltage across the energy storage unit is the voltage of the second battery unit, and the current in the energy storage unit changes in the opposite direction.

[0034] By adjusting the duty cycle of the first switching mode and the second switching mode, the magnitude and direction of the equalization current flowing through the energy storage unit are controlled, thereby transferring energy between different battery cells in the battery pack.

[0035] Optionally, the second terminal of the switched capacitor circuit is used to connect to an external power supply or load;

[0036] When an external power source is connected to the second terminal of the switched capacitor circuit, the DC-DC converter transfers energy from the external power source to the battery pack, thereby charging and balancing the battery pack.

[0037] When a load is connected to the second terminal of the switched capacitor circuit, the DC-DC converter transfers energy from the battery pack to the load, thereby achieving battery pack balancing during the discharge process.

[0038] Secondly, this application provides a control method for a DC-DC converter, the DC-DC converter including a switched capacitor circuit and an equalization circuit, the first terminal of the switched capacitor circuit being connected to a battery pack, the battery pack including a first battery cell and a second battery cell connected in series, the switched capacitor circuit having an intermediate node; the first terminal of the equalization circuit being connected to the connection node between the first battery cell and the second battery cell, the second terminal of the equalization circuit being connected to the intermediate node;

[0039] The method includes:

[0040] When the voltages of the first battery cell and the second battery cell are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switching transistor in the switched capacitor circuit, so as to control the equalization current of the equalization circuit between the first battery cell and the second battery cell, thereby achieving voltage equalization of the battery pack.

[0041] Optionally, when the voltages of the first battery cell and the second battery cell are inconsistent, modulating the voltage of the intermediate node by adjusting the duty cycle of the switching transistor in the switched capacitor circuit to control the balancing current of the balancing circuit between the first battery cell and the second battery cell includes:

[0042] When the voltage of the first battery cell is higher than that of the second battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switch in the switched capacitor circuit is increased to raise the voltage of the intermediate node, thereby driving the equalization current to flow from the first battery cell to the second battery cell.

[0043] When the voltage of the second battery cell is higher than that of the first battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switch in the switched capacitor circuit is reduced to lower the voltage of the intermediate node, thereby driving the equalization current to flow from the second battery cell to the first battery cell.

[0044] Thirdly, this application provides a chip including the DC-DC converter described in the first aspect.

[0045] Fourthly, this application provides an electronic device including the chip described in the third aspect.

[0046] This application provides a DC-DC converter and its control method, chip, and electronic device, including a switched capacitor circuit, an equalization circuit, and a control unit. The first terminal of the switched capacitor circuit is connected to a battery pack, which includes a first battery cell and a second battery cell connected in series. The switched capacitor circuit has an intermediate node. The first terminal of the equalization circuit is connected to a connection node between the first and second battery cells, and the second terminal of the equalization circuit is connected to the intermediate node. The control unit is connected to the control terminals of each switch in the switched capacitor circuit. When the absolute value of the voltage difference between the first and second battery cells exceeds a preset threshold, the control unit modulates the voltage of the intermediate node by adjusting the duty cycle of the switch in the switched capacitor circuit, thereby controlling the equalization current of the equalization circuit between the first and second battery cells to achieve voltage equalization of the battery pack. This application's solution reuses existing switched capacitor circuits and integrates an equalization circuit. When the voltages of the first and second battery cells are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switch in the switched capacitor circuit, thereby controlling the equalization current of the equalization circuit between the first and second battery cells to achieve voltage equalization of the battery pack. Based on this, efficient active battery equalization can be achieved while reducing hardware costs and size. This not only avoids the energy dissipation loss of passive equalization, but also reduces the additional losses caused by adding a separate power circuit for the equalization function, thereby significantly improving the available capacity and overall lifespan of the battery pack. Attached Figure Description

[0047] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0048] Figure 1 This is a schematic diagram of a balanced circuit.

[0049] Figure 2 Schematic diagram of the DC-DC voltage converter provided in this application Figure 1 ;

[0050] Figures 3-6 A schematic diagram of the operation of the DC-DC voltage converter provided in this application;

[0051] Figure 7 Schematic diagram of the DC-DC voltage converter provided in this application Figure 2 ;

[0052] Figures 8-11 This is a schematic diagram of the operation of the DC-DC voltage converter provided in this application.

[0053] Figure label:

[0054] 10-Equalization circuit; 101-Energy storage unit; 102-Switching unit; Inductor-L1; Switching transistor Q5A;

[0055] 20 - Switched capacitor circuit; 201 - First bridge arm unit; 202 - Second bridge arm unit;

[0056] Q1A - First switching transistor; Q2A - Second switching transistor; Q3A - Third switching transistor; Q4A - Fourth switching transistor; Q1B - Fifth switching transistor; Q2B - Sixth switching transistor; Q3B - Seventh switching transistor; Q4B - Eighth switching transistor; CF1 - First flying capacitor; CF2 - Second flying capacitor.

[0057] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0058] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0059] With the widespread adoption of mobile computing and portable electronic devices, users are increasingly demanding higher battery life and efficiency. For example, high-performance devices such as laptops and tablets typically use a multi-cell battery architecture (e.g., 4S, meaning four cells in series) to meet system power requirements.

[0060] In practical applications, due to initial differences in battery cells, uneven temperature distribution during use, and different aging rates, the voltage, capacity, and internal resistance of individual cells in a series-connected battery pack will be inconsistent, resulting in an "imbalance" phenomenon. This phenomenon causes the battery with the highest or lowest voltage to reach the protection threshold first during charging and discharging, forcing the entire battery pack to stop working prematurely. This severely reduces the usable capacity of the battery pack and the device's battery life, and accelerates the overall aging of the battery pack.

[0061] Therefore, battery power balancing is necessary. Currently, passive balancing techniques can be used, such as... Figure 1As shown, by controlling the on and off states of switches S1 and S2, a resonant network is formed using inductors L1 and L2 and capacitor C1 to transfer energy from a battery with a higher voltage to a battery with a lower voltage.

[0062] However, separate power devices such as inductors (L1, L2), capacitors (C1), and switching transistors (S1, S2) are required for the equalization function, which increases the material cost, volume, and wiring complexity of the system, and the added circuit will generate significant losses.

[0063] To address this issue, this application proposes a DC-DC voltage converter that reuses existing switched-capacitor circuits while integrating an equalization circuit. When the voltages of the first and second battery cells are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switching transistors in the switched-capacitor circuit. This controls the equalization current in the equalization circuit between the first and second battery cells, achieving voltage equalization of the battery pack. Based on this, efficient active battery equalization can be achieved while reducing hardware costs and size. This not only avoids the energy dissipation losses of passive equalization but also reduces the additional losses caused by adding a separate power circuit for the equalization function, thereby significantly improving the usable capacity and overall lifespan of the battery pack.

[0064] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0065] Figure 2 A schematic diagram of the DC-DC voltage converter provided in this application is shown below. Figure 2 As shown, the method includes: a switched capacitor circuit 20, an equalization circuit 10, and a control unit (not shown in the figure).

[0066] The first end of the switched capacitor circuit 20 is connected to the battery pack, which includes a first battery cell and a second battery cell connected in series. The switched capacitor circuit 20 has an intermediate node.

[0067] The first end of the equalization circuit 10 is connected to the connection node between the first battery cell and the second battery cell, and the second end of the equalization circuit 10 is connected to the intermediate node.

[0068] The control unit is connected to the control terminals of each switching transistor in the switched capacitor circuit 20;

[0069] The control unit is configured to: when the absolute value of the voltage difference between the first battery cell and the second battery cell is greater than a preset threshold, modulate the voltage of the intermediate node by adjusting the duty cycle of the switching transistor in the switched capacitor circuit 20, so as to control the equalization current of the equalization circuit 10 between the first battery cell and the second battery cell, thereby achieving voltage equalization of the battery pack.

[0070] In this embodiment, the existing switched capacitor circuit 20 is reused, and the equalization circuit 10 is integrated. When the absolute value of the voltage difference between the first battery cell and the second battery cell is less than or equal to a preset threshold, it indicates that the battery pack is in a good equalization state. At this time, the control unit controls the equalization circuit 10 to not work, and only the switched capacitor circuit 20 operates independently to complete its main power conversion task with high efficiency and avoid introducing any additional equalization losses.

[0071] When the absolute value of the voltage difference between the first and second battery cells exceeds a preset threshold, it indicates an imbalance in the battery pack. At this time, the control unit controls the balancing circuit 10 to enter the working state. Simultaneously, by adjusting the duty cycle of the switching transistor in the switched capacitor circuit 20, the voltage of the intermediate node inside the switched capacitor circuit 20 is dynamically modulated. A controllable voltage difference is formed between the voltage of this intermediate node and the voltage of the battery cell connection node (the connection node between the first and second battery cells). This voltage difference acts on the balancing circuit 10, driving the balancing circuit 10 to generate a balancing current whose direction and magnitude are controllable. This balancing current directly transfers energy between the battery cells, allowing the battery cell with higher voltage to replenish charge to the battery cell with lower voltage until the voltage difference returns to within the preset threshold.

[0072] This solution reuses the switched capacitor circuit of the main power conversion stage, requiring only a very small number of additional components to achieve active balancing, which significantly reduces material costs and circuit board area, perfectly meeting the high integration requirements of portable devices.

[0073] Compared to the energy dissipation of passive balancing, this solution fundamentally avoids energy waste through direct energy transfer between batteries. Compared to traditional active balancing solutions that require a separate, complete power stage, this solution reduces switching, conduction, and drive losses caused by the additional power stage.

[0074] Furthermore, this efficient balancing mechanism can quickly correct battery imbalances, maximize the usable capacity of the battery pack, and extend the device's battery life. Simultaneously, by maintaining consistent voltage between cells, it effectively prevents overcharging and over-discharging, thereby significantly improving the battery pack's cycle life and operational safety.

[0075] For example, a battery pack may be composed of multiple battery modules connected in series, and each battery module may contain multiple battery cells connected in parallel or in series. The first battery cell and the second battery cell may refer to these two battery modules. For instance, in a 4S architecture battery pack formed by two 2S battery modules connected in series, the first battery cell and the second battery cell respectively refer to these two 2S modules.

[0076] For example, the switched capacitor circuit 20 may include multiple intermediate nodes, and the equalization circuit 10 may be connected to any one of the intermediate nodes.

[0077] Optionally, the second battery cell is grounded; the control unit is configured to: when the voltage of the first battery cell is higher than the voltage of the second battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, increase the duty cycle of the target group switch in the switched capacitor circuit to increase the voltage of the target intermediate node, thereby driving the equalization current to flow from the first battery cell to the second battery cell.

[0078] When the voltage of the second battery cell is higher than that of the first battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group of switches in the switched capacitor circuit is reduced to lower the voltage of the target intermediate node, thereby driving the balancing current to flow from the second battery cell to the first battery cell. Here, the target group of switches refers to a combination of switches that can affect the voltage of the target intermediate node.

[0079] When the voltage of the first battery cell is high, the control unit increases the duty cycle of the target group switch transistor in the switched capacitor circuit. The increased duty cycle of the target group switch transistor causes the average voltage of the corresponding target intermediate node to rise, so as to modulate it to be higher than the voltage of the battery cell connection point, so as to generate a balanced current flowing from the first battery cell to the second battery cell in the equalization circuit, thereby enabling the first battery cell to charge the second battery cell and reduce the voltage of the first battery cell.

[0080] When the voltage of the second battery cell is high, the control unit reduces the duty cycle of the target group switching transistor in the switched capacitor circuit. The reduced duty cycle of the target group switching transistor causes the average voltage of the corresponding target intermediate node to decrease, so as to modulate it to be lower than the voltage of the battery cell connection point. This generates a balanced current flowing from the second battery cell to the first battery cell in the equalization circuit, thereby enabling the second battery cell to charge the first battery cell and reduce the voltage of the second battery cell.

[0081] For example, based on the step-down conversion of the switched capacitor circuit with a rated duty cycle (e.g., 50%), when the voltage of the first battery cell is detected to be higher than that of the second battery cell and the absolute value of the voltage difference exceeds a threshold, the control unit increases the average voltage of the target intermediate node by increasing the duty cycle of the switch associated with the target intermediate node (e.g., making it greater than 50%), thereby driving the equalization current to flow from the first battery cell to the second battery cell.

[0082] Optional, such as Figure 2 As shown, the voltage regulation circuit includes a switching unit 102 and an energy storage unit 101. The first terminal of the switching unit 102 serves as the first terminal of the equalization circuit 10, connecting the connection node of the first battery unit and the second battery unit. The first terminal of the energy storage unit 101 serves as the second terminal of the equalization circuit 10, connecting to an intermediate node of the switched capacitor circuit 20. The second terminal of the energy storage unit 101 is connected to the second terminal of the switching unit 102. The control unit is configured to control the switching unit 102 to be in a conducting state during equalization, so as to form an equalizing current in the energy storage unit 101.

[0083] The switching unit 102 serves as an electronic switch for balancing the current path. Its first terminal is connected to the connection node between the first and second battery units, and its second terminal is connected to the energy storage unit 101. The control unit controls the switching unit 102 to turn on and off. When the switching unit 102 is on, an energy transfer loop can be established between the first and second battery units. When the switching unit 102 is off, the energy transfer loop between the first and second battery units is disconnected, avoiding unnecessary losses or interference. The energy storage unit 101 serves as a temporary storage and transfer medium for balancing energy. Its first terminal is connected to at least one intermediate node of the switched capacitor circuit 20, and its second terminal is connected to the second terminal of the switching unit 101.

[0084] When the need to initiate equalization is detected, the control unit first controls the switching unit 102 to conduct, thereby establishing a physical path for energy transfer. Simultaneously, based on the equalization direction (e.g., energy needs to be transferred from the higher-voltage first battery cell to the lower-voltage second battery cell), the control unit dynamically modulates the voltage of the intermediate node by adjusting the duty cycle of the corresponding switching transistor in the switched capacitor circuit 20.

[0085] Thus, a controllable voltage difference is formed across the energy storage unit 101. Under the action of this voltage difference, a controlled equalization current will be generated in the energy storage unit 101 (e.g., an inductor). The direction of this current is determined by the polarity of the voltage difference across the energy storage unit 101, and its rate of change is determined by the magnitude of the voltage difference and the characteristic parameters of the energy storage unit 101.

[0086] During the equalization period, the control unit maintains the required voltage difference by adjusting the duty cycle in a closed loop, thereby stabilizing the equalization current at the target value and achieving precise charging or discharging of the battery cells. When the battery voltage difference returns to within the threshold, the control unit turns off the switching unit 102 to disconnect the equalization circuit, and then switches the control mode of the switched capacitor circuit 20 back to the normal power conversion mode.

[0087] For example, the control unit can be a dedicated function module integrated inside the DC-DC converter, or it can be the original central processing unit or power management unit in an electronic device (such as a mobile phone or a laptop). The control logic of this embodiment is implemented by configuring its software or firmware.

[0088] It should be noted that the structure of the equalization circuit 10 described above is only one embodiment for achieving the purpose of this application. Besides the specific embodiment described above, the equalization circuit 10 can also be implemented using other feasible circuit topologies. For example, the equalization circuit 10 can also be an H-bridge inductor circuit including a bidirectional switch, a coupling circuit based on multi-winding magnetic elements, a switched capacitor charge pump circuit, or an integrated precision current source module, etc. As long as the circuit can form a controllable equalization current between battery cells using the modulation voltage of the intermediate node under the action of the control unit, it is acceptable.

[0089] In one possible implementation, the energy storage unit 101 may include an inductor L1. Based on the inductor's characteristics V = L × di / dt, a controlled balancing current will begin to rise or fall linearly within the inductor.

[0090] It should be noted that the energy storage unit 101 can also be implemented in other ways, such as by coupling inductors or transformers, switched capacitor networks, etc.

[0091] In one possible implementation, the switching unit 102 includes a switching transistor Q5A, such as... Figure 1 As shown. Switch Q5A is responsible for turning the equalization path on or off.

[0092] For example, the switching transistor may include a MOS (Metal-Oxide-Semiconductor Field-Effect Transistor), such as an NMOS. The switching transistor may also be an IGBT (Insulated Gate Bipolar Transistor), a BJT (Bipolar Junction Transistor), etc.

[0093] Optional, such as Figure 1As shown, the switched capacitor circuit 20 includes a first bridge arm unit 201, a second bridge arm unit 202, a first flying capacitor CF1, and a second flying capacitor CF2. The first bridge arm unit 201 and the second bridge arm unit 202 each include a first terminal, a second terminal, a third terminal, a fourth terminal, and a fifth terminal.

[0094] When the first end of the first bridge arm unit 201 serves as the first end of the switched capacitor circuit 20, the second end of the first bridge arm unit 201 serves as the second end of the switched capacitor circuit 20; when the first end of the first bridge arm unit 201 serves as the second end of the switched capacitor circuit 20, the second end of the first bridge arm unit 201 serves as the first end of the switched capacitor circuit 20; the third end of the first bridge arm unit 201 is grounded.

[0095] It should be noted that the DC-DC converter provided in this application can be used between the battery pack and the load, such as... Figure 2 As shown, it can also be used between an external power source and a battery pack, such as... Figure 7 As shown. The external power source can be a power adapter, solar photovoltaic panel, fuel cell, or any other device capable of providing DC power. The load can include various functional modules in electronic devices, such as core processing units that require low-voltage, high-current power (e.g., central processing unit, graphics processor, memory controller), and peripheral functional modules that require specific operating voltages (e.g., USB interface circuits, audio codec circuits, display driver circuits, etc.).

[0096] like Figure 2 As shown, when the DC-DC converter is used between the battery pack and the load, the first terminal of the switched capacitor circuit 20 is connected to the battery pack, and the second terminal of the switched capacitor circuit 20 is connected to the load. In this case, the first terminal of the switched capacitor circuit 20 is also the input terminal, and the second terminal is also the output terminal. Correspondingly, the first terminal of the first bridge arm unit 201 serves as the first terminal of the switched capacitor circuit 20, connected to the battery pack, and the second terminal of the first bridge arm unit 201 serves as the second terminal of the switched capacitor circuit 20, connected to the load.

[0097] like Figure 7 As shown, when the DC-DC converter is used between the external power supply and the battery pack, the first terminal of the switched capacitor circuit 20 is connected to the battery pack, and the second terminal of the switched capacitor circuit 20 is connected to the external power supply. In this case, the first terminal of the switched capacitor circuit 20 is also the output terminal of the switched transistor capacitor circuit 20, and the second terminal is also the input terminal of the switched transistor capacitor circuit 20. Correspondingly, the first terminal of the first bridge arm unit 201 serves as the second terminal of the switched capacitor circuit 20, connected to the external power supply, and the second terminal of the first bridge arm unit 201 serves as the first terminal of the switched capacitor circuit 20, connected to the battery pack.

[0098] The first end of the second bridge arm unit 202 is connected to the first end of the first bridge arm unit 201, the second end of the second bridge arm unit 202 is connected to the second end of the first bridge arm unit 201, and the third end of the second bridge arm unit 202 is grounded.

[0099] The first end of the first flying capacitor CF1 is connected to the fourth end of the first bridge arm unit 201; the second end of the first flying capacitor CF1 is connected to the fifth end of the first bridge arm unit 201; wherein, the connection point between the second end of the first flying capacitor CF1 and the fifth end of the first bridge arm unit 201 constitutes the first intermediate node.

[0100] The first terminal of the second flying capacitor CF2 is connected to the fourth terminal of the second bridge arm unit 202, and the second terminal of the second flying capacitor CF2 is connected to the fifth terminal of the second bridge arm unit 202; wherein, the connection point between the second terminal of the second flying capacitor CF2 and the fifth terminal of the second bridge arm unit 202 constitutes a second intermediate node. The first intermediate node and the second intermediate node are two intermediate nodes in the switched capacitor circuit 20. Correspondingly, the equalization circuit 10 can be connected to either the first intermediate node or the second intermediate node.

[0101] Both the first bridge arm unit 201 and the second bridge arm unit 202 contain multiple power switching transistors. The first, second, and third ends of the first and second bridge arm units 201 and 202 constitute the main power port, which is used to connect external circuits (such as battery packs, power supplies, or loads). The fourth and fifth ends of the first and second bridge arm units 201 and 202 are internal connection ports, which are dedicated to connecting flying capacitors.

[0102] Specifically, in scenarios where DC-DC converters are used to power loads from battery packs:

[0103] For the first bridge arm unit 201: its first end serves as the high-voltage input terminal, connected to the positive terminal of the battery pack; its second end serves as the ground terminal, connected to the negative terminal of the battery pack (or system ground); its third end serves as the voltage output terminal, connected to the load. Its fourth and fifth ends are connected to the first flying capacitor CF1.

[0104] For the second bridge arm unit 202: its first end is also connected to the positive terminal of the battery pack (high voltage input terminal); its second end is grounded; its third end serves as another voltage output terminal (or is connected in parallel with the output terminal of the first bridge arm unit). Its fourth and fifth ends are connected to the second flying capacitor CF2.

[0105] During operation, the control unit precisely controls the switching transistors inside each bridge arm unit, causing its fourth and fifth terminals (i.e., the flying capacitor connection terminals) to periodically connect to different main power ports (first, second, and third terminals). This process drives the flying capacitor to switch rapidly between charging and discharging states, thereby efficiently pumping charge from the high-voltage input terminal (battery pack) to the voltage output terminal (load), achieving a step transformation of DC voltage.

[0106] In applications where the power source charges the battery pack:

[0107] For the first bridge arm unit 201: its first terminal serves as the voltage input terminal, connected to the positive terminal of the external power supply; its second terminal serves as the voltage output terminal, connected to the positive terminal of the battery pack; its third terminal serves as the ground terminal, connected to the common ground (system ground) of the power supply and the battery pack. Its fourth and fifth terminals are still connected to the first flying capacitor CF1.

[0108] For the second bridge arm unit 202: its first end is also connected to the positive terminal of the external power supply (voltage input terminal); its second end is connected to the positive terminal of the battery pack (voltage output terminal); its third end is grounded. Its fourth and fifth ends are connected to the second flying capacitor CF2.

[0109] At this time, the circuit operates in buck charging mode. The control unit drives the flying capacitors CF1 and CF2 to periodically draw charge from the voltage input terminal (external power supply) and redistribute it to the voltage output terminal (battery pack) by controlling the timing of the switching transistors, thereby converting the higher power supply voltage into a lower voltage suitable for battery charging.

[0110] The first flying capacitor CF1 and the second flying capacitor CF2 are the core energy storage and transfer components for this circuit to achieve voltage conversion. They rapidly complete charging and discharging in each switching cycle, and their function is to achieve temporary storage and spatial redistribution of charge, rather than long-term energy storage, thereby completing power transfer with extremely high efficiency.

[0111] In some embodiments, such as Figure 2 As shown, both the first bridge arm unit 201 and the second bridge arm unit 202 include four cascaded switching transistors. The first end of the first switching transistor serves as the first end of the corresponding bridge arm unit, the connection end of the first two switching transistors serves as the fourth end of the corresponding bridge arm unit, the connection end of the middle two switching transistors serves as the third end of the corresponding bridge arm unit, the connection end of the last two switching transistors serves as the fifth end of the corresponding bridge arm unit, and the second end of the last switching transistor serves as the second end of the corresponding bridge arm unit.

[0112] Specifically, such as Figure 1As shown, the first bridge arm unit 201 includes a first switch Q1A, a second switch Q2A, a third switch Q3A, and a fourth switch Q4A. The first end of the first switch Q1A serves as the first end of the first bridge arm unit 201; the second end of the second switch Q2A is connected to the first end of the third switch Q3A, serving as the fourth end of the first bridge arm unit 201; the second end of the second switch Q2A is connected to the first end of the third switch Q3A, serving as the third end of the first bridge arm unit 201; the second end of the third switch Q3A is connected to the first end of the fourth switch Q4A, serving as the fifth end of the first bridge arm unit 201; and the second end of the fourth switch Q4A serves as the second end of the first bridge arm unit 201.

[0113] The second bridge arm unit 202 includes a fifth switch Q1B, a sixth switch Q2B, a seventh switch Q3B, and an eighth switch Q4B. The first end of the fifth switch Q1B serves as the first end of the second bridge arm unit 202; the second end of the fifth switch Q1B is connected to the first end of the sixth switch Q2B, serving as the fourth end of the second bridge arm unit 202; the second end of the sixth switch Q2B is connected to the first end of the seventh switch Q3B, serving as the third end of the second bridge arm unit 202; the second end of the seventh switch Q3B is connected to the first end of the eighth switch Q4B, serving as the fifth end of the second bridge arm unit 202; and the second end of the eighth switch Q4B serves as the second end of the second bridge arm unit 202.

[0114] Correspondingly, voltage conversion can be achieved by alternating the conduction of each switch in the first bridge arm unit 201 and the second bridge arm unit 202.

[0115] For example, the control unit can provide drive signals with specific timing and phase relationships to each switch in the first bridge arm unit 201 and the second bridge arm unit 202, so that they can be turned on and off alternately and complementaryly, and the connection relationship between the flying capacitor and the input terminal, output terminal and ground of the switching circuit can be periodically reconstructed.

[0116] For example, each switch in the first bridge arm unit 201 and the second bridge arm unit 202 is a MOS, with the drain of the MOS serving as the first terminal of the switch and the source of the MOS serving as the second terminal of the switch.

[0117] It should be noted that the specific implementation of the switched capacitor circuit 20 described above is only an example. The switched capacitor circuit 20 may include three or more bridge arm units to form a multiphase interleaved structure, further reducing input and output ripple and improving power level.

[0118] For example, the DC-DC converter may also include a control switch QB connected between the input of the switched capacitor circuit 20 and the battery pack, for controlling whether the switched capacitor circuit 20 performs voltage conversion.

[0119] Optionally, the DC-DC converter has a first operating mode and a second operating mode. The first operating mode is a pure buck conversion mode, and the second operating mode is an equalized buck conversion mode. In the first operating mode, the equalization circuit does not operate; only the switched capacitor circuit operates to perform efficient buck conversion on the input voltage. In the second operating mode, the equalization circuit and the switched capacitor circuit work together. While the switched capacitor circuit completes the buck conversion, the voltage of at least one intermediate node is actively modulated to drive the equalization circuit to transfer energy between different battery cells in the battery pack, achieving battery equalization.

[0120] The control unit is configured to: monitor the voltage of each battery cell in the battery pack; control the DC-DC converter to operate in a first operating mode when the absolute value of the difference between the voltage of the first battery cell and the voltage of the second battery cell is less than or equal to a preset threshold; and control the DC-DC converter to operate in a second operating mode when the absolute value of the difference between the voltage of the first battery cell and the voltage of the second battery cell is greater than the preset threshold.

[0121] For example, taking a two-phase interleaved 4:2 buck converter circuit with switched capacitors as an example, its working principle in the first operating mode is explained. The first phase power stage consists of the first bridge arm unit 201 and its associated first flying capacitor CF1; the second phase power stage consists of the second bridge arm unit 202 and its associated second flying capacitor CF2. The control signals of the two phases have a 180° phase difference, causing them to conduct alternately.

[0122] (1) In the scenario where the battery pack supplies power to the load

[0123] like Figure 3 As shown, the first switch Q1A, the third switch Q3A, the sixth switch Q2B, and the eighth switch Q4B are turned on, while the remaining switches are turned off. This results in:

[0124] Main power path: The battery pack voltage charges the first flying capacitor CF1 through the first conducting switch Q1A, while the first flying capacitor CF1 discharges to the load through the third conducting switch Q3A.

[0125] Auxiliary path: The second flying capacitor CF2 is connected in parallel to the output of the switched capacitor circuit 20 through the conducting sixth switch Q2B and eighth switch Q4B to provide current to the load.

[0126] like Figure 4As shown, the second switch Q2A, the fourth switch Q4A, the fifth switch Q1B, and the seventh switch Q3B are turned on, while the remaining switches are turned off. This results in:

[0127] Main power path: The battery pack voltage charges the second flying capacitor CF2 through the conducting non-switching transistor Q1B, while the second flying capacitor CF2 discharges to the load.

[0128] Auxiliary path: The first flying capacitor CF1 is connected in parallel to the output of the switched capacitor circuit 20 through the conducting second switch Q2A and fourth switch Q4A to provide current to the load.

[0129] (2) In the scenario where an external power source charges the battery pack

[0130] The DC-DC converter operates in reverse buck mode, and its switching timing is similar to that of the scenario described above where the battery pack supplies power to the load.

[0131] like Figure 8 As shown, the first switch Q1A, the third switch Q3A, the sixth switch Q2B, and the eighth switch Q4B are turned on, while the remaining switches are turned off. This results in:

[0132] Main power path: The external power supply charges the first flying capacitor CF1 through the first conducting switch Q1A, while the first flying capacitor CF1 discharges to the battery pack through the third conducting switch Q3A.

[0133] Auxiliary path: The second flying capacitor CF2 is connected in parallel to the output of the switched capacitor circuit 20 through the conducting sixth switch Q2B and eighth switch Q4B to provide current to the battery pack.

[0134] like Figure 9 As shown, the second switch Q2A, the fourth switch Q4A, the third switch Q1B, and the seventh switch Q3B are turned on, while the remaining switches are turned off. This results in:

[0135] Main power path: The external power supply charges the second flying capacitor CF2 through the fifth switch Q1B, while the second flying capacitor CF2 discharges to the battery pack.

[0136] Auxiliary path: The first flying capacitor CF1 is connected in parallel to the output of the switched capacitor circuit 20 through the conducting second switch Q2A and fourth switch Q4A to provide current to the battery pack.

[0137] The first and second phases can operate alternately with a 50% duty cycle, ensuring that at any given time, at least one flying capacitor is charging from the input and discharging from the output, thereby achieving continuous, smooth, and low-ripple power transmission.

[0138] In some embodiments, the second battery cell is grounded; in the second operating mode, the DC-DC converter operates in a multiphase interleaved manner, including at least a first phase power stage and a second phase power stage; the duty cycle of each power stage includes at least two switching modes.

[0139] In the first switching mode, the switching unit is turned on, the first set of switching transistors in the switched capacitor circuit is turned on, so that the voltage across the energy storage unit is the difference between the voltage of the second battery unit and the voltage at the output of the switched capacitor circuit, and the current in the energy storage unit changes in the positive direction.

[0140] In the second switching mode, the switching unit remains on, and the second set of switching transistors in the switched capacitor circuit is turned on, so that the voltage across the energy storage unit is the voltage of the second battery unit, and the current in the energy storage unit changes in the opposite direction; by adjusting the duty cycle of the first switching mode and the second switching mode, the magnitude and direction of the balanced current flowing through the energy storage unit are controlled, thereby transferring energy between different battery units in the battery pack.

[0141] For example, in the second operating mode, such as Figure 5 , Figure 6 , Figure 10 and Figure 11 As shown, the switch Q5A is turned on, and works with the first bridge arm unit and the second bridge arm unit to achieve voltage balance of the battery pack.

[0142] (1) In the scenario where the battery pack supplies power to the load

[0143] In the first switching mode, such as Figure 5 As shown, control switches Q5A, Q1A, Q3A, Q2B, and Q4B are turned on, while the remaining switches are turned off. At this time, the voltage V across the inductor is... L =V 2S -V OUT The inductor current decreases; the voltage V across the first flying capacitor CF1 decreases. CF1 =V 4S -V OUT Among them, V 4S V is the voltage of the battery pack. 2S V represents the voltage at the connection node between the first and second battery cells, assuming the second battery cell is grounded, i.e., the voltage of the second battery cell itself. OUT This is the output voltage of the switched capacitor circuit.

[0144] In the second switching mode, such as Figure 6 As shown, control switches Q5A, Q2A, Q4A, Q1B, and Q3B are turned on, while the remaining switches are turned off. At this time, the voltage V across the inductor... L=V 2S The inductor current increases; the voltage across the first flying capacitor CF1 remains at V due to its large capacitance. 4S -V OUT Basically unchanged.

[0145] By adjusting the duty cycle D between the first and second switching modes, the voltage transformation ratio of the switched capacitor circuit 20 satisfies: V 2S / V OUT =1 / (1-D), realizing voltage transformation and equalization control.

[0146] (2) In the scenario where an external power source powers the battery pack

[0147] In the first switching mode, such as Figure 10 As shown, control switches Q5A, Q1A, Q3A, Q2B, and Q4B are turned on, while the remaining switches are turned off. At this time, the voltage V across the inductor is... L =V 2S -V OUT The inductor current decreases; the voltage V across the first flying capacitor CF1 decreases. CF1 =V BUS -V 2S Among them, V BUS The supply voltage for an external power source.

[0148] In the second switching mode, such as Figure 11 As shown, control switches Q5A, Q2A, Q4A, Q1B, and Q3B are turned on, while the remaining switches are turned off. At this time, the voltage V across the inductor... L =V 2S The inductor current increases; the voltage across the first flying capacitor CF1 remains at V due to its large capacitance. 4S -V OUT Basically unchanged.

[0149] By adjusting the duty cycle D between the first and second switching modes, the voltage transformation ratio of the switched capacitor circuit 20 satisfies: V 2S / V OUT =1 / (1-D), realizing voltage transformation and equalization control.

[0150] For example, since the DC-DC converter of this embodiment can be used between an external power source and a battery pack, or between a battery pack and a load, when the first terminal of the switched capacitor circuit 20 is connected to the battery pack, the second terminal of the switched capacitor circuit 20 is connected to an external power source or a load. When the second terminal of the switched capacitor circuit 20 is connected to an external power source, the DC-DC converter transfers energy from the external power source to the battery pack, achieving charging and balancing of the battery pack. When the second terminal of the switched capacitor circuit is connected to a load, the external power converter transfers energy from the battery pack to the load, achieving battery pack balancing during the discharge process.

[0151] The DC-DC converter provided in this application has been described in detail above. This application also provides a control method for the DC-DC converter. The DC-DC converter includes a switched capacitor circuit and an equalization circuit. The first terminal of the switched capacitor circuit is connected to a battery pack, which includes a first battery cell and a second battery cell connected in series. The switched capacitor circuit has an intermediate node. The first terminal of the equalization circuit is connected to the connection node between the first battery cell and the second battery cell, and the second terminal of the equalization circuit is connected to the intermediate node.

[0152] The control methods for DC-DC converters include:

[0153] When the voltages of the first and second battery cells are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switching transistor in the switched capacitor circuit to control the equalization current between the first and second battery cells, thereby achieving voltage equalization of the battery pack.

[0154] Optionally, when the voltage of the first battery cell is higher than that of the second battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switch in the switched capacitor circuit is increased to raise the voltage of the intermediate node, thereby driving the equalization current to flow from the first battery cell to the second battery cell.

[0155] When the voltage of the second battery cell is higher than that of the first battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switch in the switched capacitor circuit is reduced to lower the voltage of the intermediate node, thereby driving the equalization current to flow from the second battery cell to the first battery cell.

[0156] For example, in the case where the second battery cell is grounded and the equalization circuit is connected to the first intermediate node:

[0157] If the voltage of the first battery cell is higher than the voltage of the second battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switches (first switch Q1A and third switch Q3A) is increased to increase the voltage of the first intermediate node, thereby driving the balancing current to flow from the first battery cell to the second battery cell; if the voltage of the second battery cell is higher than the voltage of the first battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switches (first switch Q1A and third switch Q3A) is decreased to decrease the voltage of the first intermediate node, thereby driving the balancing current to flow from the second battery cell to the first battery cell.

[0158] With the second battery cell grounded and the equalization circuit connected to the second intermediate node:

[0159] If the voltage of the first battery cell is higher than the voltage of the second battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switches (the fifth switch Q1B and the seventh switch Q3B) is increased to increase the voltage of the second intermediate node, thereby driving the balancing current from the first battery cell to the second battery cell; if the voltage of the second battery cell is higher than the voltage of the first battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switches (the fifth switch Q1B and the seventh switch Q3B) is decreased to decrease the voltage of the second intermediate node, thereby driving the balancing current from the second battery cell to the first battery cell.

[0160] This application also provides a chip including the aforementioned DC-DC voltage converter.

[0161] This application also provides an electronic device including the chip described above.

[0162] For example, electronic devices may include portable devices such as laptops and tablets.

[0163] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A DC-DC voltage converter, characterized in that, include: A switched capacitor circuit (20) has its first end connected to a battery pack, the battery pack including a first battery cell and a second battery cell connected in series, and the switched capacitor circuit (20) has an intermediate node. An equalization circuit (10) has a first end connected to the connection node between the first battery cell and the second battery cell, and a second end connected to the intermediate node. The control unit is connected to the control terminals of each switching transistor in the switched capacitor circuit (20); The control unit is configured to: when the absolute value of the voltage difference between the first battery cell and the second battery cell is greater than a preset threshold, modulate the voltage of the intermediate node by adjusting the duty cycle of the switching transistor in the switched capacitor circuit (20) to control the equalization current of the equalization circuit (20) between the first battery cell and the second battery cell, thereby achieving voltage equalization of the battery pack.

2. The DC-DC converter according to claim 1, characterized in that, The equalization circuit (10) includes: The first terminal of the switching unit (102) serves as the first terminal of the equalization circuit (10); The energy storage unit (101) has its first end serving as the second end of the equalization circuit (10), and its second end is connected to the second end of the switching unit (102). The control unit is configured to control the switching unit (102) to be in an on state during balancing to form the balancing current in the energy storage unit (101).

3. The DC-DC voltage converter according to claim 2, characterized in that, The energy storage unit (101) includes: an inductor (L1); The switching unit (102) includes a switching transistor (Q5A).

4. The DC-DC converter according to claim 1, characterized in that, The switched capacitor circuit (20) includes: The first bridge arm unit (201) has its first end serving as the first end of the switched capacitor circuit (20), and its second end serving as the second end of the switched capacitor circuit (20); when its first end serves as the second end of the switched capacitor circuit (20), its second end serves as the first end of the switched capacitor circuit (20); and its third end is grounded. The second bridge arm unit (202) has its first end connected to the first end of the first bridge arm unit (201), its second end connected to the second end of the second bridge arm unit (202), and its third end grounded. The first flying capacitor (CF1) has its first end connected to the fourth end of the first bridge arm unit (201) and its second end connected to the fifth end of the first bridge arm unit (201); the connection point between the second end of the first flying capacitor (CF1) and the fifth end of the first bridge arm unit (201) forms a first intermediate node. The second flying capacitor (CF2) has its first end connected to the fourth end of the second bridge arm unit (202) and its second end connected to the fifth end of the second bridge arm unit (202); the connection point between the second end of the second flying capacitor (CF2) and the fifth end of the second bridge arm unit (202) forms a second intermediate node.

5. The DC-DC converter according to claim 4, characterized in that, The first bridge arm unit (201) includes: Four cascaded switching transistors are used. The first end of the first switching transistor serves as the first end of the first bridge arm unit (201). The connection end of the first two switching transistors serves as the fourth end of the first bridge arm unit (201). The connection end of the middle two switching transistors serves as the third end of the first bridge arm unit (201). The connection end of the last two switching transistors serves as the fifth end of the first bridge arm unit (201). The second end of the last switching transistor serves as the second end of the first bridge arm unit (201). The second bridge arm unit (202) includes: Four cascaded switching transistors are used. The first end of the first switching transistor serves as the first end of the second bridge arm unit (202). The connection end of the first two switching transistors serves as the fourth end of the second bridge arm unit (202). The connection end of the middle two switching transistors serves as the third end of the second bridge arm unit (202). The connection end of the last two switching transistors serves as the fifth end of the second bridge arm unit (202). The second end of the last switching transistor serves as the second end of the second bridge arm unit (202).

6. The DC-DC converter according to any one of claims 1-5, characterized in that, The DC-DC voltage converter has a first operating mode and a second operating mode; In the first operating mode, the switched capacitor circuit (20) operates to perform step-down conversion; In the second working mode, the switched capacitor circuit (20) and the equalization circuit (10) work together to perform step-down conversion and transfer energy between different battery cells of the battery pack based on the equalization circuit (10) to achieve battery equalization.

7. The DC-DC converter according to claim 6, characterized in that, The second battery cell is grounded; In the second operating mode, the DC-DC converter operates in a multi-phase interleaved manner, which includes at least a first phase power stage and a second phase power stage; Each power stage's duty cycle includes at least two switching modes, where: In the first switching mode, the switching unit (102) in the equalization circuit (10) is turned on, and the first set of switching tubes in the switched capacitor circuit (20) is turned on, so that the voltage across the energy storage unit (101) in the equalization circuit (10) is the difference between the voltage of the second battery unit and the voltage at the output terminal of the switched capacitor circuit, and the current in the energy storage unit (101) changes in the positive direction. In the second switching mode, the switching unit (102) is turned on, and the second set of switching transistors in the switched capacitor circuit (20) is turned on, so that the voltage across the energy storage unit (101) is the voltage of the second battery unit, and the current in the energy storage unit (101) changes in the opposite direction. By adjusting the duty cycle of the first switching mode and the second switching mode, the magnitude and direction of the equalization current flowing through the energy storage unit (101) are controlled, thereby transferring energy between different battery cells of the battery pack.

8. The DC-DC converter according to any one of claims 1-5, characterized in that, The second end of the switched capacitor circuit (20) is used to connect to an external power source or load; When an external power source is connected to the second terminal of the switched capacitor circuit (20), the DC voltage converter transfers energy from the external power source to the battery pack, thereby charging and balancing the battery pack. When a load is connected to the second terminal of the switched capacitor circuit (20), the DC voltage converter transfers energy from the battery pack to the load, thereby achieving battery pack balancing during the discharge process.

9. A control method for a DC-DC voltage converter, characterized in that, The DC-DC converter includes a switched capacitor circuit and an equalization circuit. The first end of the switched capacitor circuit is connected to a battery pack, which includes a first battery cell and a second battery cell connected in series. The switched capacitor circuit has an intermediate node. The first end of the equalization circuit is connected to the connection node between the first battery cell and the second battery cell, and the second end of the equalization circuit is connected to the intermediate node. The method includes: When the voltages of the first battery cell and the second battery cell are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switching transistor in the switched capacitor circuit, so as to control the equalization current of the equalization circuit between the first battery cell and the second battery cell, thereby achieving voltage equalization of the battery pack.

10. The method according to claim 9, characterized in that, When the voltages of the first battery cell and the second battery cell are inconsistent, the voltage of the intermediate node is modulated by adjusting the duty cycle of the switching transistor in the switched capacitor circuit to control the balancing current of the balancing circuit between the first battery cell and the second battery cell, including: When the voltage of the first battery cell is higher than that of the second battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switch in the switched capacitor circuit is increased to raise the voltage of the intermediate node, thereby driving the equalization current to flow from the first battery cell to the second battery cell. When the voltage of the second battery cell is higher than that of the first battery cell, and the absolute value of the voltage difference between the two is greater than a preset threshold, the duty cycle of the target group switch in the switched capacitor circuit is reduced to lower the voltage of the intermediate node, thereby driving the equalization current to flow from the second battery cell to the first battery cell.

11. A chip, characterized in that, Includes the DC voltage converter according to any one of claims 1-8.

12. An electronic device, characterized in that, Includes the chip described in claim 11.

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