Dual battery charging device, method and controller thereof

Abstract

A dual battery charging apparatus, method, and controller thereof, the dual battery charging apparatus comprising: a first converter having an input coupled to an input voltage bus and an output coupled to a first battery; and a second converter having an input coupled to the input voltage bus and an output coupled to a first battery and a second battery, respectively, through first and second bidirectional current blocking switches.

Description

[0001] This application is a divisional application of the invention application filed on April 19, 2022, with application number 2022104074865 and titled "Dual Battery Charging Device, Method and Controller Thereof". Technical Field

[0002] This invention relates to a dual-battery charging device, method, and controller thereof, and in a particular embodiment, to a dual-battery charging device for effectively charging a dual-battery system comprising a first battery and a second battery connected in parallel. Background Technology

[0003] With the further development of technology, various electronic devices (such as mobile phones, tablets, digital cameras, MP3 players, etc.) have become popular. Each portable device can use multiple rechargeable battery cells. Multiple rechargeable battery cells can be connected in series or in parallel to form a rechargeable battery pack for storing electrical energy.

[0004] A battery charger is used to restore the charge of a battery. The battery charger is controlled to provide voltage (e.g., constant voltage charging mode) and current (e.g., constant current charging mode) to a dual-battery system comprising a first and a second battery connected in parallel, in order to restore the charge of the dual-battery system.

[0005] There are various power conversion topologies suitable for charging batteries. Based on their differences, power conversion topologies can be divided into three categories: switching power converters, linear regulators, and switched-capacitor power converters. Compared to other topologies, switched-capacitor converters are less complex because they consist of multiple switches and flying capacitors. Therefore, switched-capacitor converters can provide a compact and efficient power supply for battery charging.

[0006] To improve battery charging performance, a dual-battery charging device may include two power stages connected in parallel between the input voltage bus and the dual-battery system. The first power stage is a charge pump. The second power stage is a switching charger. The charge pump can be implemented as a suitable switched-capacitor charger, such as a two-phase switched-capacitor converter. The first phase of the two-phase switched-capacitor converter includes four switches connected in series between the input voltage bus and ground. A first flying capacitor is connected between the common node of the two upper switches and the common node of the two lower switches. The common node of the second and third switches is connected to the output voltage bus coupled to the battery. The second phase of the two-phase switched-capacitor converter includes four switches connected in series between the input voltage bus and ground. A second flying capacitor is connected between the common node of the two upper switches and the common node of the two lower switches. The common node of the second and third switches is connected to the output voltage bus.

[0007] A switching charger can be implemented as a suitable step-down power converter, such as a buck converter. A switching charger includes two switches connected in series between the input voltage bus and ground. An inductor is connected between the common node of the two switches and the output voltage bus. The output voltage bus is coupled to the dual-battery system via an isolating switch, which provides isolation between the battery and the output voltage bus. The isolating switch includes two diodes. The first diode is located between the body terminal and the source terminal of the isolating switch. The second diode is located between the body terminal and the drain terminal of the isolating switch. These two diodes are connected back-to-back. Due to the back-to-back diode connection, the isolating switch can completely isolate the dual-battery system from the output voltage bus.

[0008] In operation, the first and second batteries are connected in parallel. The voltage of one battery may be higher than that of the other. This voltage imbalance can lead to an uneven current distribution, resulting in surge current flowing through both batteries. A simple and efficient method is desired to achieve a balanced distribution of charging current between the two batteries. Summary of the Invention

[0009] By providing a preferred embodiment of the present disclosure of a dual-battery charging device, method, and controller thereof, these and other problems are generally solved or circumvented, and overall technical advantages are achieved.

[0010] According to one embodiment, a dual-battery charging device includes: a first converter having an input coupled to an input voltage bus and an output coupled to a first battery; and a second converter having an input coupled to the input voltage bus and an output coupled to the first battery and the second battery respectively via a first bidirectional current blocking switch and a second bidirectional current blocking switch.

[0011] According to another embodiment, a dual-battery charging method includes: in a pre-charging state of a battery system comprising a first battery and a second battery connected in parallel, configuring a voltage drop converter to charge the first battery and the second battery respectively through a first battery switch and a second battery switch; in a constant-current charging state of the battery system, configuring a charge pump converter to directly charge the first battery, wherein in the constant-current charging state, at least one of the first battery switch and the second battery switch is configured to achieve charging balance between the first battery and the second battery; and in a constant-voltage charging state of the battery system, configuring a voltage drop converter to charge the first battery and the second battery, wherein at least one of the first battery switch and the second battery switch is configured to operate in an adjustment state to achieve constant-voltage charging of the first battery and the second battery.

[0012] According to another embodiment, a charging device controller includes a plurality of gate drivers configured to generate a plurality of gate drive signals for driving a switch of a charge pump converter, a switch of a voltage drop converter, a first battery switch, and a second battery switch, wherein the charge pump converter has an input coupled to an input voltage bus and an output coupled to a first battery, and the voltage drop converter has an input coupled to an input voltage bus and an output coupled to a first battery and a second battery, respectively, via the first battery switch and the second battery switch.

[0013] The features and technical advantages of this disclosure have been summarized quite broadly above to facilitate a better understanding of the detailed description that follows. Additional features and advantages of this disclosure, which form the subject matter of the claims, will be described below. Those skilled in the art will understand that the disclosed concepts and specific embodiments can be readily used as the basis for modifying or designing other structures or processes for achieving the same purpose as this disclosure. Those skilled in the art will also recognize that such equivalent structures do not depart from the spirit and scope of this disclosure as set forth in the appended claims. Attached Figure Description

[0014] To gain a more complete understanding of the invention and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, wherein: Figure 1 Block diagrams of dual-battery charging devices according to various embodiments of the present disclosure are shown; Figure 2 Various embodiments according to this disclosure are shown as follows: Figure 1 A schematic diagram of the dual-battery charging device is shown; Figure 3 Various embodiments of the present disclosure are shown for driving Figure 1 The controller for the switch of the dual-battery charging device shown; Figure 4 Controls according to various embodiments of the present disclosure are shown. Figure 1 The flowchart of the dual-battery charging device is shown.

[0015] Unless otherwise stated, corresponding numbers and symbols in the different figures generally refer to corresponding parts. These figures are drawn to clearly illustrate relevant aspects of the various embodiments and are not necessarily drawn to scale. Detailed Implementation

[0016] The following discusses in detail the preparation and use of the present preferred embodiments. However, it should be understood that this disclosure provides many applicable inventive concepts that can be embodied in various specific contexts. The specific embodiments discussed are merely illustrative of specific ways of preparing and using the invention and do not limit the scope of the invention.

[0017] This disclosure will be described with reference to a preferred embodiment in a specific context, namely a dual-battery charging device and control method. However, this disclosure can also be applied to various power systems. Various embodiments will be described in detail below with reference to the accompanying drawings.

[0018] Figure 1 A block diagram of a dual-battery charging device according to various embodiments of the present disclosure is shown. The dual-battery charging device includes a first charging unit 102 and a second charging unit 104. The first charging unit 102 has an input coupled to an input voltage bus VIN and an output coupled to a first battery (battery I). The second charging unit 104 has one input and three outputs. The input of the second charging unit 104 is coupled to the input voltage bus VIN. A first output (BAT1) of the second charging unit 104 is coupled to the first battery. A second output (BAT2) of the second charging unit 104 is coupled to a second battery (battery II). A third output of the second charging unit 104 is coupled to a system voltage bus (VSYS). In some embodiments, VSYS can be used to directly power other system components. In another embodiment, VSYS can be used to power other system components via an additional power system such as a voltage regulator.

[0019] In some embodiments, the first charging unit 102 includes a charge pump. More specifically, the charge pump may be a two-phase switched capacitor converter configured to provide power to charge a first battery and a second battery in some charging state (e.g., a constant current charging state). Throughout the description, the charge pump may alternatively be referred to as a two-phase charge pump converter, a two-phase switched capacitor converter, or a first converter. The following description, in conjunction with... Figure 2 The structure and working principle of a two-phase switched capacitor converter are explained.

[0020] In some embodiments, the second charging unit 104 includes a voltage drop converter, a battery reverse blocking switch, a first battery switch, and a second battery switch. In some embodiments, the voltage drop converter may be a buck converter configured to provide power to charge the first and second batteries in some charging states (e.g., constant voltage charging states). Throughout the description, the voltage drop converter may alternatively be referred to as a buck converter or a second converter. The following description, in conjunction with... Figure 2 This describes the structure and working principle of the buck converter.

[0021] A first battery switch is connected between the output of the buck converter and the first battery. A second battery switch is connected between the output of the buck converter and the second battery. Both the first and second battery switches function as isolating switches. The first battery switch provides reverse blocking capability to isolate the first battery from various system components coupled to the VSYS. Specifically, the first battery switch is used to connect the first battery to the buck converter or disconnect the first battery from the buck converter. Furthermore, the first battery switch can be configured to operate in a regulating state to control the voltage across the first battery and / or the current flowing through the first battery. Throughout this description, the first battery switch may alternatively be referred to as a first bidirectional current blocking switch.

[0022] The second battery switch provides reverse blocking capability to isolate the second battery from various system components coupled to the VSYS. Specifically, the second battery switch is used to connect the second battery to or disconnect the second battery from the buck converter. Furthermore, the second battery switch can be configured to operate in a regulated state to control the voltage across the second battery and / or the current flowing through it. Throughout this description, the second battery switch may alternatively be referred to as a second bidirectional current blocking switch.

[0023] A battery reverse blocking switch is connected between the input voltage bus and the input of the buck converter. The battery reverse blocking switch is used to connect the buck converter to the input power supply coupled to VIN or to disconnect the buck converter from the input power supply.

[0024] In some embodiments, the buck converter switch, the battery reverse blocking switch, the first battery switch, and the second battery switch are integrated in a first semiconductor chip. The charge pump switch is integrated in a second semiconductor chip. In another embodiment, the charge pump switch, the buck converter switch, the battery reverse blocking switch, the first battery switch, and the second battery switch are integrated in a single semiconductor chip.

[0025] The dual-battery charging device also includes a controller (not shown, but...). Figure 3 As shown in the diagram, it is configured to generate gate drive signals for the charge pump switch, buck converter switch, battery reverse blocking switch, first battery switch, and second battery switch. Furthermore, the controller is configured to control the operation of each switch based on multiple operating parameters. Specifically, the controller is configured to generate gate drive signals for configuring the first and second battery switches during the charging process of the dual-battery system, thereby achieving a balanced distribution of charging current between the first and second batteries. The following will combine... Figure 3-4 Describe the detailed working principle of the controller.

[0026] have Figure 1An advantageous feature of the illustrated battery charging device is that it enables a simple and efficient method to achieve balanced charging current distribution between the first and second batteries without requiring additional wiring resistance compensation techniques. Eliminating additional wiring resistance significantly improves the efficiency of the dual-battery charging device and increases charging speed. Furthermore, achieving balanced charging current distribution between the first and second batteries significantly reduces inrush current.

[0027] Figure 2 Various embodiments according to this disclosure are shown. Figure 1 The diagram shows a schematic of a dual-battery charging device. The dual-battery charging device includes a two-phase switched-capacitor converter, a buck converter, a battery reverse blocking switch QB1, a first battery switch BATFET1, and a second battery switch BATFET2. Figure 2 As shown, the input of the two-phase switched-capacitor converter is connected to the input voltage bus VIN. The input of the buck converter is connected to the input voltage bus VIN via the battery reverse blocking switch QB1. The output of the two-phase switched-capacitor converter is connected to the first battery (Battery I). The output of the buck converter is connected to the system voltage bus VSYS. The output of the buck converter is connected to the first battery via the first battery switch BATFET1. The output of the buck converter is connected to the second battery (Battery II) via the second battery switch BATFET2.

[0028] In some embodiments, the first battery can be implemented as a single-cell battery. Alternatively, the first battery can be implemented as a multi-cell battery. Similarly, the second battery can be implemented as a single-cell battery. Alternatively, the second battery can be implemented as a multi-cell battery. In some embodiments, the capacity of the first battery is greater than the capacity of the second battery.

[0029] The two-phase switched capacitor converter includes two branches. The first branch includes switches Q1, Q2, Q3, and Q4 connected in series between the input voltage bus VIN and ground. A first flying capacitor CF1 is connected between the common node of Q1 and Q2 and the common node of Q3 and Q4. The second branch includes switches Q5, Q6, Q7, and Q8 connected in series between the input voltage bus VIN and ground. A second flying capacitor CF2 is connected between the common node of Q5 and Q6 and the common node of Q7 and Q8. Figure 2 As shown, the common node of Q2 and Q3 is connected to the output voltage bus Vo. The common node of Q6 and Q7 is also connected to the output voltage bus Vo.

[0030] In operation, the two-phase switched-capacitor converter can be configured to operate in either a 2:1 fixed PWM mode or a 1:2 fixed PWM mode. More specifically, when a power supply is connected to the input voltage bus VIN, the two-phase switched-capacitor converter converts the voltage on VIN to a lower voltage. Specifically, the output voltage (the voltage on Vo) is equal to half the input voltage (VIN / 2). In this configuration, the two-phase switched-capacitor converter operates in a 2:1 fixed PWM mode. On the other hand, when a battery is used as the power source, the two-phase switched-capacitor converter converts the voltage on Vo to a higher voltage. Specifically, the output voltage (the voltage on VIN) is twice the input voltage (the voltage on Vo). In this configuration, the two-phase switched-capacitor converter operates in a 1:2 fixed PWM mode. In this disclosure, when a power supply (e.g., the receiving coil of a wireless power transmission system) is connected to VIN, the two-phase switched-capacitor converter is configured to operate in a 2:1 fixed PWM mode to provide power to both the first and second batteries.

[0031] In operation, the working principle of the first branch is similar to that of the second branch, except that the drive signals of the first branch (e.g., Q1) and the second branch (e.g., Q5) are 180 degrees out of phase. For simplicity, the working principle of the first branch will be explained in detail below.

[0032] In operation, the first branch of the two-phase switched capacitor converter is configured to operate in two different phases. In the first phase, switches Q1 and Q3 are turned on, and switches Q2 and Q4 are turned off. Due to the conduction of switches Q1 and Q3, a first conductive path is established between VIN and Vo. This first conductive path consists of switch Q1, the first flying capacitor CF1, and switch Q3. Current flows from VIN to Vo through this first conductive path. In the first phase, the first flying capacitor CF1 is charged, and energy is stored accordingly in it.

[0033] During the second phase, switches Q1 and Q3 are off, and switches Q2 and Q4 are on. Because switches Q2 and Q4 are on, a second conductive path is established. This second conductive path consists of switch Q4, the first flying capacitor CF1, and switch Q2. In the second phase, the current discharges the first flying capacitor CF1, and the energy stored in it decreases accordingly.

[0034] The buck converter includes a high-side switch Q11 and a low-side switch Q12 connected in series between the input voltage bus VIN and ground. The buck converter also includes an inductor L1 connected between the common node of the high-side switch Q11 and the low-side switch Q12 and the output bus of the buck converter.

[0035] It should be noted that Figure 2The illustrations shown are merely examples and should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, substitutions, and modifications. For example, the first converter can be implemented as a multiphase charge pump converter. The second converter can be implemented as any suitable power regulator, such as a linear regulator.

[0036] According to one embodiment, Figure 2 The switches (e.g., switches Q1-Q8, Q11-Q12, QB1, BATFET1, and BATFET2) can be metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar junction transistors (BJTs), superjunction transistors (SJTs), insulated gate bipolar transistors (IGBTs), gallium nitride (GaN)-based power devices, etc.

[0037] It should be noted that, although Figure 2 Display switches Q1-Q8 and Q11-Q12 are implemented as single n-type transistors, but those skilled in the art will recognize that many variations, modifications, and substitutions are possible. For example, depending on different applications and design requirements, at least some switches (e.g., Q11) can be implemented as p-type transistors. BATFET1 and BATFET2 can be implemented as two back-to-back connected transistors. Furthermore, Figure 2 Each switch shown can be implemented as multiple switches connected in parallel. Furthermore, a capacitor can be connected in parallel with a switch to implement zero-voltage switching (ZVS) / zero-current switching (ZCS).

[0038] Figure 2 Further illustration shows that switches Q1-Q8 are integrated in the first semiconductor chip 103. Switches Q11, Q12, QB1, BATFET1, and BATFET2 are integrated in the second semiconductor chip 105. It should be noted that... Figure 2 The semiconductor chips shown are merely examples and should not be used to unduly limit the scope of the claims. Those skilled in the art will recognize many variations, substitutions, and modifications. For example, depending on design requirements and different applications, Q1-Q8, Q11, Q12, QB1, BATFET1, and BATFET2 can be integrated into a single semiconductor chip.

[0039] In operation, during the pre-charge state of the dual-battery system comprising a first battery and a second battery, the dropout converter is configured to charge the first battery and the second battery respectively via a first battery switch BATFET1 and a second battery switch BATFET2. The first battery switch BATFET1 can be configured to operate in a first regulation state to control the voltage across the first battery and / or the current flowing through the first battery. The second battery switch BATFET2 can be configured to operate in a second regulation state to control the voltage across the second battery and / or the current flowing through the second battery.

[0040] In the constant-current charging state of the dual-battery system, the charge pump converter is configured to directly charge the first battery. In the constant-current charging state, at least one of the first battery switch BATFET1 and the second battery switch BATFET2 is configured to achieve charging balance between the first and second batteries.

[0041] In the constant-current charging state of the dual-battery system, the dual-battery charging device can operate in four different system configurations. In the first system configuration under constant-current charging, the first battery switch BATFET1 is configured to be fully turned on. The second battery switch BATFET2 is configured to operate in a regulating state to achieve a balanced distribution of charging current between the first and second batteries.

[0042] In the second system configuration under constant current charging, the second battery switch BATFET2 is configured to be fully turned on. The first battery switch BATFET1 is configured to operate in a regulating state to achieve a balanced distribution of charging current between the first and second batteries.

[0043] In the third system configuration under constant current charging, the first battery switch BATFET1 and the second battery switch BATFET2 are configured to operate in a first regulation state and a second regulation state, respectively, to achieve a balanced distribution of charging current between the first and second batteries. Furthermore, the ratio of the voltage drop across the first battery switch BATFET1 to the voltage drop across the second battery switch BATFET2 is dynamically adjusted based on the temperatures of the first and second battery switches BATFET1 and BATFET2.

[0044] In the fourth system configuration under constant current charging, the first battery switch BATFET1 and the second battery switch BATFET2 are configured to operate in two different modes. In the first mode, the first battery switch BATFET1 is fully turned on, and the second battery switch BATFET2 is configured to operate in a second adjustment state to achieve a balanced distribution of charging current between the first and second batteries. In the second mode, the second battery switch BATFET2 is fully turned on, and the first battery switch BATFET1 is configured to operate in a first adjustment state to achieve a balanced distribution of charging current between the first and second batteries. Under constant current charging conditions in the dual-battery system, the first and second operating modes alternate to achieve better performance of the dual-battery charging device.

[0045] In the constant-voltage charging state of the dual-battery system, the dropout converter is configured to charge the first and second batteries. At least one of the first battery switch BATFET1 and the second battery switch BATFET2 is configured to operate in a regulating state to achieve constant-voltage charging of the first and second batteries.

[0046] In the constant-voltage charging state of the dual-battery system, the dual-battery charging device can operate in four different system configurations. In the first system configuration of constant-voltage charging, the dropout converter is configured to provide a stable voltage. The first battery switch BATFET1 is configured to operate in a first regulation state to achieve constant-voltage charging of the first battery. The second battery switch BATFET2 is configured to operate in a second regulation state to achieve constant-voltage charging of the second battery.

[0047] In the second system configuration under constant-voltage charging, the dropout converter is configured to provide a stable voltage applied to the first battery by fully turning on the first battery switch BATFET1. The second battery switch BATFET2 is used to operate in a second regulation state to achieve constant-voltage charging of the second battery.

[0048] In the third system configuration with constant voltage charging, the dropout converter is configured to provide a stable voltage applied to the second battery by fully turning on the second battery switch BATFET2. The first battery switch BATFET1 is configured to operate in a first regulation state to achieve constant voltage charging of the first battery.

[0049] In the fourth system configuration under constant-voltage charging conditions, the first battery switch BATFET1 and the second battery switch BATFET2 are configured to operate in two different modes. In the first mode, the first battery switch BATFET1 is configured to operate in a first regulation state to achieve constant-voltage charging of the first battery. The second battery switch BATFET2 is configured to operate in a second regulation state to achieve constant-voltage charging of the second battery. In the second mode, one of the first and second battery switches BATFET1 and BATFET2 is configured to be fully on, and the other switch is configured to operate in a regulation state. During the constant-voltage charging state of the battery system, the first and second operating modes alternate to achieve better performance of the dual-battery charging device.

[0050] During operation, when no power is available at the input voltage bus VIN and the voltage of the second battery is higher than that of the first battery, the second battery is configured to provide power to the system bus and charge the first battery.

[0051] In the constant-current charging state of the dual-battery system, the first battery switch BATFET1 is off, and the second battery switch BATFET2 is on. In response to this configuration, a charge pump can be used to charge the first battery. A buck converter charges the second battery.

[0052] It should be noted that, although Figure 2 The dual-battery charging device shown is used to charge a dual-battery system, but it can also be used to charge a multi-cell battery system. For example, in a three-battery system, an additional battery switch can be added to achieve the aforementioned functionality. Figure 2 The function.

[0053] Figure 3 Various embodiments of the present disclosure are shown for driving Figure 1 The controller 110 of the dual-battery charging device shown includes 13 gate drivers and multiple signal processing units for processing various operating parameters, such as the voltages of the first and second batteries.

[0054] by Figure 2 In a specific embodiment, the first gate driver is configured to generate a first gate drive signal applied to the gate of Q1. The second gate driver is configured to generate a second gate drive signal applied to the gate of Q2. The third gate driver is configured to generate a third gate drive signal applied to the gate of Q3. The fourth gate driver is configured to generate a fourth gate drive signal applied to the gate of Q4. The fifth gate driver is configured to generate a fifth gate drive signal applied to the gate of Q5. The sixth gate driver is configured to generate a sixth gate drive signal applied to the gate of Q6. The seventh gate driver is configured to generate a seventh gate drive signal applied to the gate of Q7. The eighth gate driver is configured to generate an eighth gate drive signal applied to the gate of Q8. The ninth gate driver is configured to generate a ninth gate drive signal applied to the gate of Q11. The tenth gate driver is configured to generate a tenth gate drive signal applied to the gate of Q12. The eleventh gate driver is configured to generate an eleventh gate drive signal applied to the gate of QB1. The twelfth gate driver is configured to generate a twelfth gate drive signal applied to the gate of BATFET1. The thirteenth gate driver is configured to generate a thirteenth gate drive signal applied to the gate of BATFET2.

[0055] During operation, in the pre-charge state of the dual-battery system, the controller 110 is configured... Figure 2 The voltage drop converter shown charges the first and second batteries respectively via a first battery switch and a second battery switch. In the constant current charging state of the dual-battery system, the controller 110 is configured... Figure 2The charge pump converter shown directly charges the first battery. In constant current charging mode, at least one of the first battery switch and the second battery switch is configured to achieve charging balance between the first and second batteries. In constant voltage charging mode of the dual-battery system, the controller 110 configures a voltage drop converter to charge the first and second batteries. At least one of the first battery switch and the second battery switch is configured to operate in a regulating state to achieve constant voltage charging of the first and second batteries.

[0056] It should be noted that the controller 110 with 13 gate drivers described above is merely an example and should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, substitutions, and modifications. For example, external gate drivers can be used to further enhance the driving capability.

[0057] Figure 4 Various embodiments according to this disclosure are shown, such as Figure 1 The flowchart shown is for controlling the dual-battery charging device. Figure 4 The flowchart shown is merely an example and should not unduly limit the scope of the claims. Those skilled in the art will recognize many variations, substitutions, and modifications. For example, additions, deletions, substitutions, rearrangements, and repetitions may be made. Figure 4 The various steps are shown.

[0058] Return to reference Figure 2 The charge pump converter is connected between the input voltage bus and the first battery. The input of the dropout converter is coupled to the input voltage bus, and its output is coupled to the first and second batteries respectively via the first battery switch and the second battery switch. (Return to Reference) Figure 3 The controller includes multiple gate drivers. These gate drivers are configured to generate multiple gate drive signals for driving the charge pump converter and the dropout converter.

[0059] In step 402, in the pre-charge state of the battery system including the first battery and the second battery connected in parallel, the voltage drop converter is configured to charge the first battery and the second battery respectively through the first battery switch and the second battery switch.

[0060] In step 404, during the constant current charging state of the battery system, the charge pump converter is configured to directly charge the first battery. During the constant current charging state, at least one of the first battery switch and the second battery switch is configured to achieve charging balance between the first battery and the second battery.

[0061] In step 406, under the constant-voltage charging state of the battery system, the voltage drop converter is configured to charge the first battery and the second battery. At least one of the first battery switch and the second battery switch is configured to operate in a regulating state to achieve constant-voltage charging of the first battery and the second battery.

[0062] The method further includes configuring a voltage drop converter to provide a stable voltage and configuring a first battery switch to operate in a first adjustment state to achieve constant voltage charging of the first battery under constant voltage charging conditions of the battery system, and configuring a second battery switch to operate in a second adjustment state to achieve constant voltage charging of the second battery.

[0063] The method further includes configuring a voltage drop converter to provide a stable voltage applied to the first battery by fully turning on the first battery switch during the constant voltage charging state of the battery system, and configuring the second battery switch to operate in a second regulation state to achieve constant voltage charging of the second battery.

[0064] The method further includes configuring a voltage drop converter to provide a stable voltage applied to the second battery by fully turning on the second battery switch during the constant voltage charging state of the battery system, and configuring the first battery switch to operate in a first regulation state to achieve constant voltage charging of the first battery.

[0065] The method further includes configuring a first battery switch to operate in a first adjustment state in a first operating mode to achieve constant voltage charging of the first battery, and configuring a second battery switch to operate in a second adjustment state to achieve constant voltage charging of the second battery. In the second operating mode, one of the first battery switch and the second battery switch is configured to be fully turned on, and the other switch is configured to operate in the adjustment state. In the constant voltage charging state of the battery system, the first operating mode and the second operating mode are alternately operated.

[0066] Return to reference Figure 2 A charge pump converter is a two-phase switched capacitor converter. A dropout converter is a buck converter.

[0067] The method also includes configuring the first battery switch to be fully turned on and the second battery switch to be operated in a regulating state during the constant current charging state of the battery system, so as to achieve a balanced distribution of charging current between the first battery and the second battery.

[0068] The method also includes configuring the second battery switch to be fully turned on and the first battery switch to be operated in a regulating state during the constant current charging state of the battery system, so as to achieve a balanced distribution of charging current between the first battery and the second battery.

[0069] The method further includes configuring the first battery switch and the second battery switch to operate in a first adjustment state and a second adjustment state respectively under the constant current charging state of the battery system, so as to achieve a balanced distribution of charging current between the first battery and the second battery, wherein the ratio of the voltage drop on the first battery switch to the voltage drop on the second battery switch can be dynamically adjusted based on the temperature of the first battery switch and the temperature of the second battery.

[0070] The method further includes, under the constant current charging state of the battery system, in the first operating mode, fully turning on the first battery switch and configuring the second battery switch to operate in the second adjustment state to achieve a balanced distribution of charging current between the first battery and the second battery; in the second operating mode, fully turning on the second battery switch and configuring the first battery switch to operate in the first adjustment state to achieve a balanced distribution of charging current between the first battery and the second battery, wherein, under the constant current charging state of the battery system, the first operating mode and the second operating mode are alternately performed.

[0071] Return to reference Figure 2 The charge pump converter includes a first switch, a second switch, a third switch, and a fourth switch connected in series between the input voltage bus and ground; a first flying capacitor connected between the common node of the first and second switches and the common node of the third and fourth switches; a fifth switch, a sixth switch, a seventh switch, and an eighth switch connected in series between the input voltage bus and ground; and a second flying capacitor connected between the common node of the fifth and sixth switches and the common node of the seventh and eighth switches. The common node of the second and third switches is connected to the common node of the sixth and seventh switches and further connected to the output of the charge pump converter.

[0072] Return to reference Figure 2 The dropout converter includes a high-side switch and a low-side switch connected in series between the input voltage bus and ground, and an inductor connected between the common node of the high-side switch and the low-side switch and the output bus of the dropout converter.

[0073] Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0074] Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, apparatuses, methods, and steps described in the specification. As will be readily understood by those skilled in the art from the disclosure of this document, there are processes, machines, manufactures, compositions of matter, means, methods, or steps that currently exist or will be developed thereafter, performing substantially the same function or achieving substantially the same results as the corresponding embodiments described herein that are available according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, apparatuses, methods, or steps within their scope.

Claims

1. A dual-battery charging device, comprising: The first converter has an input coupled to an input voltage bus and an output coupled to a first battery; and The second converter has an input coupled to an input voltage bus and outputs coupled to a first battery and a second battery respectively via a first bidirectional current blocking switch and a second bidirectional current blocking switch. In a constant-current charging state of the first battery and the second battery, the first bidirectional current blocking switch is configured to be off, the second bidirectional current blocking switch is configured to operate in a regulating state, and both the first and second converters are configured to operate. The first converter directly charges the first battery, and the second converter charges the second battery via the second bidirectional current blocking switch. The second bidirectional current blocking switch is configured to achieve charging balance between the first battery and the second battery.

2. The dual-battery charging device as described in claim 1, wherein: The first converter is a two-phase switched-capacitor converter; and The second converter is a buck converter.

3. The dual-battery charging device as described in claim 2, wherein, The two-phase switched capacitor converter includes: The first switch, the second switch, the third switch, and the fourth switch are connected in series between the input voltage bus and ground; The first flying capacitor is connected between the common node of the first and second switches and the common node of the third and fourth switches; The fifth, sixth, seventh, and eighth switches are connected in series between the input voltage bus and ground; and A second flying capacitor is connected between the common node of the fifth and sixth switches and the common node of the seventh and eighth switches, wherein the common node of the second and third switches is connected to the common node of the sixth and seventh switches, and further connected to the output terminal of the two-phase switched capacitor converter.

4. The dual-battery charging device as described in claim 2, wherein, The buck converter includes: The high-voltage side switch and the low-voltage side switch are connected in series between the input and ground of the buck converter; and An inductor is connected between the common node of the high-voltage side switch and the low-voltage side switch and the output bus of the buck converter.

5. The dual-battery charging device as claimed in claim 4, further comprising: A battery reverse blocking switch is connected between the input of the buck converter and the input voltage bus.

6. The dual-battery charging device as described in claim 5, wherein: The switch of the first converter, the switch of the second converter, the battery reverse blocking switch, the first bidirectional current blocking switch and the second bidirectional current blocking switch are integrated in the same semiconductor chip.

7. The dual-battery charging device as claimed in claim 1, further comprising: The controller is configured to generate gate drive signals for configuring the first converter and the second converter during the charging process of the first battery and the second battery to achieve charging balance between the first battery and the second battery.

8. A dual-battery charging method, comprising: In the pre-charge state of a battery system including a first battery and a second battery connected in parallel, a voltage drop converter is configured to charge the first battery and the second battery respectively through the first battery switch and the second battery switch; In the constant current charging state of the battery system, the first battery switch is configured to be off, the second battery switch is configured to operate in an adjustment state, and the charge pump converter and voltage drop converter are configured to operate. The charge pump converter directly charges the first battery, and the voltage drop converter charges the second battery through the second battery switch. The second battery switch is configured to achieve charging balance between the first and second batteries. In the constant voltage charging state of the battery system, the voltage drop converter is configured to charge the first battery and the second battery, wherein at least one of the first battery switch and the second battery switch is configured to operate in an adjustment state to achieve constant voltage charging of the first battery and the second battery.

9. The dual-battery charging method as described in claim 8, further comprising: During the constant-voltage charging state of the battery system, the voltage drop converter is configured to provide a stable voltage; The first battery switch is configured to operate in a first adjustment state to achieve constant voltage charging of the first battery; and The second battery switch is configured to operate in a second adjustment state to achieve constant voltage charging of the second battery.

10. The dual-battery charging method as described in claim 8, further comprising: In the constant voltage charging state of the battery system, the voltage drop converter is configured to provide a stable voltage to the first battery by fully turning on the first battery switch; and The second battery switch is configured to operate in a second adjustment state to achieve constant voltage charging of the second battery.

11. The dual-battery charging method as described in claim 8, further comprising: In the constant voltage charging state of the battery system, the voltage drop converter is configured to provide a stable voltage to the second battery by fully turning on the second battery switch; and The first battery switch is configured to operate in a first adjustment state to achieve constant voltage charging of the first battery.

12. The dual-battery charging method as described in claim 8, further comprising: In the first operating mode, the first battery switch is configured to operate in the first adjustment state to achieve constant voltage charging of the first battery, and the second battery switch is configured to operate in the second adjustment state to achieve constant voltage charging of the second battery. and In the second operating mode, one of the first battery switch and the second battery switch is configured to be fully turned on, and the other of the first battery switch and the second battery switch is configured to operate in the adjustment state, wherein the first operating mode and the second operating mode are alternately operated under the constant voltage charging state of the battery system.

13. The dual-battery charging method as described in claim 8, wherein: The charge pump converter is a two-phase switched capacitor converter; and The voltage drop converter is a buck converter.

14. A charging device controller, comprising: Multiple gate drivers are configured to generate multiple gate drive signals for driving the switches of the charge pump converter, the voltage drop converter, the first battery switch, and the second battery switch, wherein: The charge pump converter has an input coupled to an input voltage bus and an output coupled to a first battery; and The voltage drop converter has an input coupled to the input voltage bus and outputs coupled to the first battery and the second battery respectively through the first battery switch and the second battery switch. In the constant current charging state of the first battery and the second battery, the first battery switch is configured to be off, the second battery switch is configured to operate in an adjustment state, and the charge pump converter and the voltage drop converter are configured to operate. The charge pump converter directly charges the first battery, and the voltage drop converter charges the second battery through the second battery switch. The second battery switch is configured to achieve charging balance between the first battery and the second battery.

15. The charging device controller according to claim 14, wherein, The controller is configured such that: In the pre-charge state of a battery system including the first battery and the second battery connected in parallel, the voltage drop converter is configured to charge the first battery and the second battery respectively through the first battery switch and the second battery switch; and In the constant voltage charging state of the battery system, a voltage drop converter is configured to charge the first battery and the second battery, wherein at least one of the first battery switch and the second battery switch is configured to operate in an adjustment state to achieve constant voltage charging of the first battery and the second battery.

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