Multi-port usb charging system and control method thereof

Abstract

A multi-port USB charging system and a control method thereof are provided. The charging system includes n AC / DC power supply modules, n USB output ports, n parallel switch modules, and a single control chip, wherein the n USB output ports are respectively connected to the n AC / DC power supply modules, any two of the n AC / DC power supply modules are connected with one parallel switch module, the control chip is connected to the n AC / DC power supply modules and the n parallel switch modules, and is configured to, when detecting that one or more of the n USB output ports is connected with a mobile terminal device, perform the following processing at a set frequency: sampling output currents of the n AC / DC power supply modules; judging whether to start current sharing control based on the output currents of the n AC / DC power supply modules; and in the case of needing to start current sharing control, adjusting output voltages or output currents of one or more of the n AC / DC power supply modules.

Description

Technical Field

[0001] This invention relates to the field of circuits, and more specifically to a multi-port USB charging system and its control method. Background Technology

[0002] With the increasing variety of mobile terminal devices, single-port Universal Serial Bus (USB) charging systems can no longer meet the demand for charging multiple devices simultaneously. To enable simultaneous charging of multiple mobile terminal devices, multi-port USB charging systems have emerged on the market. Summary of the Invention

[0003] A multi-port USB charging system according to an embodiment of the present invention includes n AC-to-DC (AC / DC) power modules, n USB output ports, and The system consists of a parallel switch module and a single control chip, where n is an integer greater than 1. Specifically: n USB output ports are connected to n AC / DC power modules; a parallel switch module connects any two AC / DC power modules; and the control chip is connected to the n AC / DC power modules and... A parallel switching module is configured to perform the following processing at a set frequency when a mobile terminal device is detected connected to one or more of the n USB output ports: sampling the output current of the n AC / DC power modules; determining whether current sharing control needs to be activated based on the output current of the n AC / DC power modules; and adjusting the output voltage or output current of one or more of the n AC / DC power modules if current sharing control needs to be activated.

[0004] According to an embodiment of the present invention, a control method for a multi-port USB charging system is provided, wherein the multi-port USB charging system includes n AC-to-DC (AC / DC) power modules, n USB output ports, and... There are n parallel switch modules, where n is an integer greater than 1. The n USB output ports are respectively connected to n AC / DC power modules. A parallel switch module is connected between any two AC / DC power modules. The control method includes: when a mobile terminal device is detected connected to one or more of the n USB output ports, performing the following processing at a set frequency: sampling the output current of the n AC / DC power modules; determining whether current sharing control needs to be activated based on the output current of the n AC / DC power modules; and adjusting the output voltage or output current of one or more of the n AC / DC power modules if current sharing control needs to be activated.

[0005] According to the multi-port USB charging system and control method of the present invention, the set frequency can be set as needed, thereby improving the current sharing control accuracy between AC / DC power modules to the desired level. Attached Figure Description

[0006] The invention can be better understood from the following description of specific embodiments of the invention in conjunction with the accompanying drawings, wherein:

[0007] Figure 1 A schematic block diagram of the system architecture of a conventional multi-port USB charging system is shown.

[0008] Figure 2 A schematic block diagram of the system architecture of another traditional multi-port USB charging system is shown.

[0009] Figure 3 It shows the use of Figure 2 The diagram shows a schematic block diagram of a dual-port USB charging system.

[0010] Figure 4 A schematic block diagram of the system architecture of a multi-port USB charging system according to an embodiment of the present invention is shown.

[0011] Figure 5 It shows Figure 4 The diagram shows an example implementation of the parallel switch module.

[0012] Figure 6 It shows Figure 4 The diagram shows a schematic block diagram of the internal functional units of the control chip.

[0013] Figure 7 It shows the use of Figure 4 The diagram shows a schematic block diagram of a dual-port USB charging system.

[0014] Figure 8 It shows the use of Figure 4 The flowchart shows the control method of the multi-port USB charging system. Detailed Implementation

[0015] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific configurations and algorithms presented below, but covers any modifications, substitutions, and improvements to elements, components, and algorithms without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description in order to avoid unnecessarily obscuring the invention.

[0016] Figure 1 A schematic block diagram of a conventional multi-port USB charging system 100 is shown. Figure 1 As shown, the multi-port USB charging system 100 includes a single AC-to-DC (AC / DC) power module 102, multiple DC-to-DC (DC / DC) power modules 104-1 to 104-n (n is an integer greater than 0), multiple USB output ports 106-1 to 106-n, a single control chip 108, and communication lines between the control chip 108 and each DC / DC power module. The AC / DC power module 102 outputs DC voltage based on AC voltage, and the DC / DC power module 104i (i is an integer, and 1≤i≤n) outputs DC voltage to the USB output port 106-i based on the DC voltage from the AC / DC power module 102 under the control of the control chip 108. In a multi-port USB charging system 100 that is a dual-port USB charging system (i.e., n=2) with a total output power of 60W, if a mobile terminal device is plugged into only one USB output port, that USB output port can output 60W of power; if mobile terminal devices are plugged into both USB output ports, each USB output port can output 30W of power. Compared with the traditional single-port USB charging system, an additional DC / DC power module is required, resulting in an energy efficiency reduction of about 8%. Furthermore, when mobile terminal devices are plugged into both USB output ports, each USB output port only outputs 30W of power, which is a waste of resources for selecting a DC / DC power module that supports a maximum of 60W.

[0017] Figure 2 A schematic block diagram of another conventional multi-port USB charging system 200 is shown. (See diagram for example.) Figure 2As shown, the multi-port USB charging system 200 includes multiple AC / DC power modules 202-1 to 202-n (n is an integer greater than 0), multiple control chips 204-1 to 204-n, multiple USB output ports 206-1 to 206-n, a parallel switch module between any two AC / DC power modules, and a communication line between any two control chips. The AC / DC power module 202i (1≤i≤n) outputs DC voltage to the USB output port 206-i or to the USB output port connected to it via the parallel switch module, based on AC voltage, under the control of the control chip 204-i. Here, when more than one USB output port is connected to a mobile terminal device, the corresponding control chip distributes power by adjusting the output voltage of the corresponding AC / DC power module. In the case where the multi-port USB charging system 200 is a dual-port USB charging system (i.e., n=2) and its total output power is 60W, if only one USB output port is connected to a mobile terminal device, that USB output port can output 60W of power, compared to... Figure 1 The multi-port USB charging system 100 shown can eliminate the need for a DC / DC power module, resulting in higher energy efficiency. However, it requires an additional parallel switch module to combine the output power of the two AC / DC power modules and provide it to one USB output port. If mobile terminal devices are plugged into both USB output ports, each USB output port can output 30W of power, adapting to the selection of 30W power devices for each AC / DC power module.

[0018] exist Figure 2 In the multi-port USB charging system shown, the current sharing control accuracy depends on the voltage adjustment step size of the control chip and the impedance of the parallel switching module. For example, when the voltage adjustment step size of the control chip is 10mV and the impedance Rdson of the parallel switching module is 10mohm, the current difference in the parallel switching module caused by each voltage adjustment step of the control chip is 10mV / 10mohm, or 1A, indicating poor current sharing control accuracy. To improve the current sharing control accuracy to 0.1A, the voltage adjustment step size of the control chip needs to be reduced to 1mV, which would significantly increase the internal resources of the control chip; or the impedance Rdson of the parallel switching module needs to be increased to 100mohm, which would reduce the energy efficiency of the multi-port USB charging system.

[0019] Figure 3 It shows the use of Figure 2 The diagram shows a schematic block diagram of a dual-port USB charging system 300. Figure 3In the dual-port USB charging system 300 shown, AC / DC power module 302-1 is connected to USB output port 306-1 via control chip 304-1, AC / DC power module 302-2 is connected to USB output port 306-2 via control chip 304-2, parallel switch module 308 is connected between AC / DC power modules 302-1 and 302-2 and between control chips 304-1 and 304-2, and control chips 304-1 and 304-2 exchange information via a communication bus. Figure 3 In the dual-port USB charging system shown, in order to prevent the output voltage from backflowing and causing the power supply to open loop under no-load or light-load conditions, the parallel switch module 308 is in the off state by default. When the output is suddenly loaded, it cannot change from the off state to the on state in real time, which results in a large voltage downsurge at the USB output port. Therefore, there is a problem of poor output dynamic response in the current sharing mode.

[0020] Furthermore, in the multi-port USB charging system shown in Figure 2, after the control chip corresponding to each USB output port collects the voltage / current information of the corresponding USB output port, it needs to exchange information with each other through the communication bus (requiring several bytes of data exchange). This results in slow communication speed, delayed information exchange, and susceptibility to interference, making it impossible to perform real-time, fast, and precise control of each AC / DC power module.

[0021] Given Figure 1 and Figure 2 The problems existing in the multi-port USB charging system shown are addressed by proposing a multi-port USB charging system according to an embodiment of the present invention, which can solve these problems. Figure 1 and Figure 2 The multi-port USB charging system shown has one or more of the following problems: poor current sharing accuracy, poor load dynamic response, open-loop output voltage backflow, slow communication speed, and susceptibility to interference.

[0022] Figure 4 A schematic block diagram of the system architecture of a multi-port USB charging system 400 according to an embodiment of the present invention is shown. Figure 4 As shown, the multi-port USB charging system 400 includes multiple AC-DC power modules 402-1 to 402-n (n is an integer greater than 0), a single control chip 404, multiple USB output ports 406-1 to 406-n, and... A parallel switch module is configured, wherein: USB output ports 402-1 to 402-n are respectively connected to AC / DC power modules 406-1 to 406-n; a parallel switch module is connected between any two AC / DC power modules 402-1 to 402-n; and control chip 404 is connected to AC / DC power modules 402-1 to 402-n and... A parallel switching module. In other words, the input terminals of AC / DC power modules 406-1 to 406 are connected in parallel, and the output terminals of any two AC / DC power modules are connected or disconnected via a parallel switching module. The control chip 404 is used to control the output voltage and output current of each AC / DC power module and the opening and closing of each parallel switching module.

[0023] Figure 5 It shows Figure 4 The diagram shows an example implementation of a parallel switch module. Figure 5 As shown, the parallel switching module can be implemented in ways including but not limited to N-type metal-oxide-semiconductor field-effect transistor (N-MOSFET) back diode, P-type metal-oxide-semiconductor field-effect transistor (P-MOSFET) back diode, N-MOSFET single transistor, or P-MOSFET single transistor.

[0024] In some embodiments, the control chip 404 can be configured to perform the following processing at a set frequency when a mobile terminal device is detected connected to one or more USB output ports (but not all n USB output ports) of USB output ports 402-1 to 402-n: sampling the output current of AC / DC power modules 402-1 to 402-n; determining whether current sharing control needs to be activated based on the output current of AC / DC power modules 402-1 to 402-n; and adjusting the output voltage or output current of one or more AC / DC power modules 402-1 to 402-n if current sharing control needs to be activated. Here, by setting the set frequency, the accuracy of current sharing control among AC / DC power modules can be improved to a desired level. For example, with the voltage regulation step size of the control chip 404 being 10mV, the impedance Rdson of the parallel switch module being 10mohm, and the closed-loop bandwidth of each AC / DC power module being 10kHz, by setting the set frequency to slightly less than 10kHz, the current difference between each AC / DC power module can be reduced to within 0.1A (i.e., the current sharing control accuracy is improved to 0.1A).

[0025] In some embodiments, the control chip 404 can also be configured to: when the output current of any one of the AC / DC power modules 402-1 to 402-n (e.g., AC / DC power module 402-i, 1≤i≤n) is less than a first set threshold or is a reverse current, control the parallel switch module connected between AC / DC power module 402-i and another AC / DC power module 402-1 to 402-n to change from an on state to an off state. Here, by controlling the parallel switch module connected between AC / DC power module 402-i and another AC / DC power module to change from an on state to an off state when the output current of AC / DC power module 402-i is less than the first set threshold or is a reverse current, current backflow to AC / DC power module 402-i can be prevented, thereby preventing open-loop abnormalities in AC / DC power module 402-i.

[0026] In some embodiments, the control chip 404 can also be configured to: when the output current of any one of the AC / DC power modules 402-1 to 402-n (e.g., AC / DC power module 402-i, 1≤i≤n) exceeds a second set threshold, control the parallel switch module connected between AC / DC power module 402-i and another AC / DC power module 402-1 to 402-n (e.g., AC / DC power module 402-k, k≠i, 1≤k≤n) to change from an off state to an on state, wherein no mobile terminal device is connected to the USB output port connected to AC / DC power module 402-k. Here, since the control chip 404 can immediately control the parallel switch module connected between AC / DC power module 402-i and AC / DC power module 402-k to change from an off state to an on state after detecting that the output current of AC / DC power module 402-i exceeds the second set threshold (without needing to... Figure 2 The system architecture shown transmits information about the output current of AC / DC power module 402-i to another control chip corresponding to AC / DC power module 402-k, so the output dynamic response speed of the multi-port USB charging system 400 is fast.

[0027] In some embodiments, the control chip 404 may also be configured to: select a current sharing control mode from a constant voltage current sharing control mode and a current limiting current sharing control mode when current sharing control needs to be activated; and adjust the output voltage or output current of one or more AC / DC power modules 402-1 to 402-n using the selected current sharing control mode.

[0028] In some embodiments, the control chip 404 can also be configured to: negotiate the output power of each AC / DC power module 402-1 to 402-n with a mobile terminal device connected to one or more USB output ports via a fast charging protocol; and control the output power of each AC / DC power module 402-1 to 402-n via constant current or constant voltage control. Here, output power can be intelligently provided to the corresponding USB output port according to the power requirements of the mobile terminal device.

[0029] Figure 6 It shows Figure 4 The diagram shows the block diagram of the internal functional units of the control chip. Figure 6 As shown, the control chip 404 integrates a current sharing control logic unit 404-1 (which can be implemented by, for example, a microcontroller unit (MCU), a constant voltage / constant current (CC / CV) control unit 404-2, a voltage / current (V / I) sampling unit 404-3, a fast charging protocol unit 404-4, a protection unit 404-5, a drive management unit 404-6, and a port detection unit 404-7. The CC / CV control unit 404-2, V / I sampling unit 404-3, fast charging protocol unit 404-4, protection unit 404-5, drive management unit 404-6, and port detection unit 404-7 work in concert under the control of the current sharing control logic unit 404-1. The system comprises the following components: CC / CV control unit 404-2 for controlling the output power of each AC / DC power module via CC or CV control; V / I sampling unit 404-3 for sampling the output voltage and current of each AC / DC power module; fast charging protocol unit 404-4 for negotiating the output power of each AC / DC power module with the mobile terminal device connected to the USB output port; protection unit 404-5 for preventing current backflow into each AC / DC power module; drive management unit 404-6 for controlling the opening and closing of each parallel switch module; and port detection unit 404-7 for detecting whether a mobile terminal device is connected to each USB output port.

[0030] It should be noted that the USB output ports 406-1 to 406-n can be USB Type-A or USB Type-C interfaces.

[0031] Below, we will adopt Figure 4 Taking the dual-port USB charging system (with a total output power of 60W) shown in the diagram as an example, for... Figure 4 The working principle of the system architecture shown is explained. Figure 7 It shows the use of Figure 4The diagram shows a schematic block diagram of a dual-port USB charging system 700. Figure 7 As shown, the parallel switch module 708 is connected between the AC / DC power modules 702-1 and 702-2, and the control chip 704 is connected to the AC / DC power modules 702-1 and 702-2 and the parallel switch module 708.

[0032] exist Figure 7 In the dual-port USB charging system 700 shown, when the maximum output power of AC / DC power modules 702-1 and 702-2 is 30W: when a mobile terminal device is connected to either USB output port 706-1 or 706-2, the parallel switch module 708 is in the open state, and the USB output port connected to the mobile terminal device outputs 60W of power, thus realizing power sharing between AC / DC power modules 702-1 and 702-2; when mobile terminal devices are connected to both USB output ports 706-1 and 706-2, the parallel switch module 708 is in the closed state, and USB output ports 706-1 and 706-2 each output 30W of power.

[0033] exist Figure 7 In the dual-port USB charging system 700 shown, when the maximum output power of AC / DC power module 702-1 is 20W and the maximum output power of AC / DC power module 702-2 is 40W: when a mobile terminal device is connected to either USB output port 706-1 or 706-2, the parallel switch module 708 is in the open state, and the USB output port connected to the mobile terminal device outputs 60W of power, thus realizing power sharing between AC / DC power modules 702-1 and 702-2; when both USB output ports 706-1 and 706-2 are connected to mobile terminal devices, the parallel switch module 708 is in the closed state, USB output port 706-1 outputs 20W of power, and USB output port 706-2 outputs 40W of power.

[0034] It is conceivable that, in adopting Figure 4 In the three-port USB charging system with the illustrated system architecture, assuming each AC / DC power module has a maximum output power of 30W: when a mobile terminal device is connected to any one USB output port, that USB output port outputs 90W, thus achieving power sharing among the three AC / DC power modules; when mobile terminal devices are connected to any two USB output ports, one USB output port outputs 60W and the other outputs 30W; when all three USB output ports are connected to mobile terminal devices, each USB output port outputs 30W. For those skilled in the art, this approach... Figure 4The operating principle of the multi-port USB charging system shown in the diagram is similar.

[0035] exist Figure 4 In the multi-port USB charging system 400 shown, the current sharing control logic unit 404-1 inside the control chip 404 can effectively solve the problem. Figure 3 The multi-port USB charging system 300 shown presents several issues related to the independent operation of multiple control chips, such as the current sharing control depending on the voltage regulation step of the control chip, the impedance of the parallel switching module, and the lag and asynchrony of interactive communication information.

[0036] Figure 8 An embodiment of the invention is shown for use with Figure 4 The flowchart shows the control method 800 of the multi-port USB charging system 400. (See flowchart for example.) Figure 8 As shown, the control method 800 includes: S802, determining whether all USB output ports of the multi-port USB charging system 400 are connected to mobile terminal devices (i.e., determining whether to enter current sharing mode); if so, not entering current sharing mode; otherwise, entering current sharing mode and executing S804 to S810 at a preset frequency; S804, sampling the output current of each AC / DC power module of the multi-port USB charging system 400; S806, determining whether the output current of at least one AC / DC power module in the multi-port USB charging system 400 is greater than a second threshold (i.e., determining whether current sharing control needs to be started); if so, proceeding to S808; otherwise, current sharing control is not required; S808, selecting a current sharing control mode from constant voltage current sharing control mode and current limiting current sharing control mode; S810, adjusting the output voltage or output current of one or more AC / DC power modules of the multi-port USB charging system 400 using the selected current sharing control mode.

[0037] Other aspects of the control method 800 correspond to other functions that the control chip 404 can achieve, so other aspects of the control method 800 will not be described in detail.

[0038] This invention can be implemented in other specific forms without departing from its spirit and essential characteristics. For example, the algorithm described in a particular embodiment can be modified without departing from the basic spirit of the invention. Therefore, the present embodiments are to be regarded as exemplary rather than limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and all changes falling within the meaning and scope of the claims and their equivalents are thus included within the scope of the invention.

Claims

1. A multi-port USB charging system, comprising n AC / DC power modules, n USB output ports, A parallel switch module and a single control chip, where n is an integer greater than 1, where: The n USB output ports are respectively connected to the n AC / DC power modules. A parallel switch module is connected between any two AC / DC power modules among the n AC / DC power modules. The control chip is connected to the n AC / DC power modules and the A parallel switch module is configured to perform the following processing at a set frequency when a mobile terminal device is detected connected to one or more of the n USB output ports: The output current of the n AC / DC power modules is sampled; Determine whether current sharing control needs to be activated based on the output current of the n AC / DC power modules. as well as When current sharing control needs to be activated, adjust the output voltage or output current of one or more of the n AC / DC power modules. By setting the set frequency, the current sharing control accuracy among the n AC / DC power modules can be improved to the desired level.

2. The multi-port USB charging system according to claim 1, wherein, The control chip is also configured to: When the output current of any one of the n AC / DC power modules is less than the first set threshold or is a reverse current, the parallel switch module connected between the one AC / DC power module and another AC / DC power module among the n AC / DC power modules is controlled to change from the on state to the off state.

3. The multi-port USB charging system according to claim 1, wherein, The control chip is also configured to: When the output current of any one of the n AC / DC power modules exceeds the second set threshold, the parallel switch module connected between the one AC / DC power module and another AC / DC power module among the n AC / DC power modules is controlled to change from the off state to the on state, wherein no mobile terminal device is connected to the USB output port connected to the other AC / DC power module.

4. The multi-port USB charging system according to claim 1, wherein, The control chip is also configured to: When current sharing control needs to be activated, select one of the following current sharing control modes: constant pressure current sharing control mode and current limiting current sharing control mode; and Using the selected current sharing control mode, the output voltage or output current of one or more of the n AC / DC power modules is adjusted.

5. The multi-port USB charging system according to claim 1, wherein, The control chip is also configured to: The output power of each of the n AC / DC power modules is negotiated with the mobile terminal device connected to the one or more USB output ports via a fast charging protocol.

6. The multi-port USB charging system according to claim 1, wherein, The control chip is also configured to: The output power of each of the n AC / DC power modules is controlled by constant current or constant voltage control.

7. A control method for a multi-port USB charging system, the multi-port USB charging system comprising n AC-to-DC (AC / DC) power modules, n USB output ports, and... There are several parallel switch modules, where n is an integer greater than 1. The n USB output ports are respectively connected to the n AC / DC power modules, and a parallel switch module is connected between any two AC / DC power modules. The control method includes: When a mobile terminal device is detected connected to one or more of the n USB output ports, the following processing is performed at a set frequency: The output current of the n AC / DC power modules is sampled; Determine whether current sharing control needs to be activated based on the output current of the n AC / DC power modules; and When current sharing control needs to be activated, adjust the output voltage or output current of one or more of the n AC / DC power modules. By setting the set frequency, the current sharing control accuracy among the n AC / DC power modules can be improved to the desired level.

8. The control method according to claim 7, further comprising: When the output current of any one of the n AC / DC power modules is less than the first set threshold or is a reverse current, the parallel switch module connected between the one AC / DC power module and another AC / DC power module among the n AC / DC power modules is controlled to change from the on state to the off state.

9. The control method according to claim 7, further comprising: When the output current of any one of the n AC / DC power modules exceeds the second set threshold, the parallel switch module connected between the one AC / DC power module and another AC / DC power module among the n AC / DC power modules is controlled to change from the off state to the on state, wherein no mobile terminal device is connected to the USB output port connected to the other AC / DC power module.

10. The control method according to claim 7, further comprising: When it is necessary to activate current sharing control, select one current sharing control mode from constant pressure current sharing control mode and current limiting current sharing control mode. as well as Using the selected current sharing control mode, the output voltage or output current of one or more of the n AC / DC power modules is adjusted.

11. The control method according to claim 7, further comprising: The output power of each of the n AC / DC power modules is negotiated with the mobile terminal device connected to the one or more USB output ports via a fast charging protocol.

12. The control method according to claim 7, further comprising: The output power of each of the n AC / DC power modules is controlled by constant current or constant voltage control.

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