阅读说明：本技术 具双电源的usb扩展装置及双电源供电方法 (USB expansion device with double power supplies and double power supply method ) 是由 谢国诚 于 2019-03-14 设计创作，主要内容包括：具双电源的USB扩展装置包括：第一电源连接接口,符合USB Type-C及电力传输规格,用以与第一电源电性连接；第二电源连接接口,用以与第二电源电性连接；主机连接接口,符合USB Type-C及电力传输的规格,用以与主机电性连接；外接接口,用以与外接设备电性连接；以及电源管理模块,与第一电源连接接口、第二电源连接接口、主机连接接口及外接接口电性连接；其中,当第一电源连接接口与第二电源连接接口同时分别与第一电源及第二电源电性连接时,对应主机通过主机连接接口要求提供电力,电源管理模块使第一电源的电力通过主机连接接口提供予主机,此时,电源管理模块使第二电源的电力通过第二电源连接接口提供予电源管理模块且通过外接接口提供予外接设备。(The USB expansion device with double power supplies comprises: the first power supply connection interface is in accordance with the USB Type-C and power transmission specification and is electrically connected with a first power supply; the second power supply connection interface is used for being electrically connected with a second power supply; the host connecting interface is in accordance with the USB Type-C and power transmission specification and is used for being electrically connected with the host; the external interface is used for being electrically connected with external equipment; the power management module is electrically connected with the first power supply connection interface, the second power supply connection interface, the host connection interface and the external interface; when the first power supply connection interface and the second power supply connection interface are electrically connected with the first power supply and the second power supply respectively, the corresponding host computer requires to provide electric power through the host computer connection interface, the power supply management module enables the electric power of the first power supply to be provided for the host computer through the host computer connection interface, and at the moment, the power supply management module enables the electric power of the second power supply to be provided for the power supply management module through the second power supply connection interface and provided for the external equipment through the external interface.)

1. A USB expansion device with dual power supplies is characterized by comprising:

the first power supply connection interface is in accordance with the USB Type-C and power transmission specification and is used for being electrically connected with a first power supply;

the second power supply connection interface is used for being electrically connected with a second power supply;

the host connecting interface conforms to the USB Type-C and power transmission specifications and is used for being electrically connected with a host;

the external interface is used for being electrically connected with at least one external device; and

the power management module is electrically connected with the first power connection interface, the second power connection interface, the host connection interface and the at least one external interface;

the first power supply connection interface and the second power supply connection interface are electrically connected with the first power supply and the second power supply respectively, the power supply management module enables the power of the first power supply to be supplied to the host through the host connection interface corresponding to the requirement of the host through the host connection interface, and at the moment, the power supply management module enables the power of the second power supply to be supplied to the power supply management module through the second power supply connection interface and to be supplied to the at least one external device through the at least one external interface.

2. The USB expansion device with dual power supplies of claim 1, wherein the power management module further comprises a power supply and demand transaction processing unit and a power supply and demand switch and conversion unit.

3. The USB expansion device with dual power supplies according to claim 2, wherein the step of providing power corresponding to the requirement of the host through the host connection interface further comprises: the power supply and demand transaction processing unit inquires the power supply power of the first power supply through the first power supply connection interface, the host inquires the power supply power through the host connection interface, and the host provides the required power supply power through the host connection interface according to the power supply power replied by the power supply and demand transaction processing unit.

4. The USB expansion device with dual power supplies of claim 2, wherein the power management module provides the power of the first power source to the host through the host connection interface further comprises: the power supply and demand transaction processing unit provides the first power supply connection interface with the power supply power required by the host through the host connection interface, the power supply and demand transaction processing unit informs the power supply and demand switch and conversion unit to start a power supply transmission channel between the first power supply connection interface and the host connection interface, and the power of the first power supply is provided to the host through the host connection interface.

5. The USB expansion device with dual power supplies of claim 2, wherein the power supply and demand switch and conversion unit can detect the power states of the first power connection interface and the host connection interface and accept the power state inquiry of the power supply and demand transaction processing unit.

6. The USB expansion device with dual power supplies of claim 2, wherein the power supply and demand switch and the conversion unit have DC power conversion and voltage regulation functions, and can open/close the power channel between the first power connection interface and the host connection interface.

7. The USB expansion device with dual power supplies of claim 1, wherein the first power connection interface comprises a configuration channel for communicating with the power management module and determining the power supply.

8. The USB expansion device with dual power supplies of claim 1, wherein the first power supply is a DC power supply.

9. A dual power supply method is applied to a USB expansion device which accords with USB power transmission specification, the USB expansion device comprises a first power supply connection interface, a second power supply connection interface, a host connection interface, at least one external interface and a power supply management module, the first power supply connection interface accords with the USBType-C and the power transmission specification and is electrically connected with a first power supply, the second power supply connection interface is electrically connected with a second power supply, the host connection interface accords with the USB Type-C and the power transmission specification and is electrically connected with a host, and the at least one external interface is electrically connected with at least one external device; the method comprises the following steps:

communicating power supply/receiving information meeting USB Type-C and USB power transmission specifications between the first power supply and the host;

providing the power of the first power supply to the host through the host connecting interface according to the power supply/receiving information; and

the power of the second power supply is provided to the power supply management module through the second power supply connection interface and is provided to the at least one external device through the at least one external interface;

wherein the objects receiving the electric power of the first power supply and the second power supply are different.

10. The dual power supply method of claim 9, wherein the power management module further comprises a power supply and demand transaction processing unit and a power supply and demand switch and conversion unit.

11. The dual power supply method of claim 10, wherein the step of communicating power supplying/receiving information conforming to USB type-C and USB power transmission specifications between the first power source and the host further comprises: the power supply and demand transaction processing unit inquires the power supply power of the first power supply through the first power supply connection interface, the host inquires the power supply power through the host connection interface, and the host provides the required power supply power according to the power supply power replied by the power supply and demand transaction processing unit through the host connection interface.

12. The dual power supply method of claim 10, wherein the step of providing the power of the first power source to the host through the host connection interface according to the power supply/receiving information further comprises: the power supply and demand transaction processing unit provides the power supply power required by the host to the first power supply connection interface, the power supply and demand transaction processing unit informs the power supply and demand switch and conversion unit to start a power supply transmission channel between the first power supply connection interface and the host connection interface, and the power of the first power supply is provided to the host through the host connection interface.

13. The dual power supply method of claim 10, wherein the power supply and demand switch and conversion unit detects power states of the first power connection interface and the host connection interface and accepts power status inquiry of the power supply and demand transaction processing unit.

14. The dual power supply method of claim 10, wherein the power supply and demand switch and the switching unit have dc power conversion and voltage regulation functions, and can open/close a power channel between the first power connection interface and the host connection interface.

15. The dual power supply method of claim 9, wherein the first power connection interface comprises a configuration channel for communicating with the power management module and determining the power supply.

16. The dual power supply method of claim 9, wherein the first power source is a dc power source.

Technical Field

The present invention relates to a USB expansion device, and more particularly, to an expansion device with dual Power sources supporting USB Type-C and Power transmission (Power Delivery) specifications.

Background

Due to the design consideration of light weight and portability, the number of USB connection interfaces of the existing notebook computer or tablet computer is decreasing, but there is still a need to connect USB devices such as a mouse, a keyboard, a printer, a projector, an optical drive, and an external hard disk for use, so that the demand for USB expansion devices capable of connecting USB devices additionally is increasing. USB expansion devices such as USB hubs (hubs) and USB Docking stations (Docking stations) allow multiple USB external devices to be connected to a USB host (e.g., a laptop or a tablet computer), thereby increasing the number of external USB devices that can be connected to the USB host.

Referring to fig. 1, fig. 1 is a block diagram of a conventional single power USB power supply system. The USB expansion device 100 of the conventional non-USB Type-C specification and without a Power Delivery (PD) function is electrically connected to an external Direct Current (DC) Power source and uses the external DC Power source as a Power source, or is electrically connected to the Power supply unit 120 at the same time, wherein the Power supply unit 120 may be an external DC Power source or/and a USB Power supply, and selects one of the external DC Power source and the USB Power supply as a Power supply source, that is, the two cases both use a single Power source as the Power supply source. When the USB power supply is used as a power source, if the total power consumption of the USB external devices (151, 152, 153) connected to the USB expansion apparatus 100 is higher than the power supplied by the USB power supply, the USB external devices may be damaged or may cause power utilization risks.

On the other hand, when an external dc power source is used as the power supply source, the external dc power source is usually selected to have a power consumption standard higher than that of the USB external device (151, 152, 153) to prevent the power consumption from being higher than the power supply. However, there may be a case where an external dc power supply with a standard other than the higher standard is adopted, and in this case, the total power consumption may be higher than the power supply amount of the external dc power supply, and various adverse conditions and possible power consumption dangerous conditions may also occur.

In addition, as described above, for the USB expansion device 100 supporting the USB Type-C specification and the USB Power transfer (Power Delivery) function, in addition to the external dc power supply meeting the power consumption specification of the USB expansion device 100, the power consumption of the host 130 and the external devices (151, 152, 153) connected to the USB expansion device 100 should be considered, so that the host 130 cannot be charged when the power supply of the external dc power supply is insufficient, or slow charging, or various bad conditions of the USB expansion device 100 and the external devices (151, 152, 153), or even dangerous situations such as excessive load overheating to burning, so the external dc power supply usually needs to be supported by a high power supply (e.g. 120WPower Adapter), however, as a result, unnecessary energy is consumed, and the power demand of the host 130 cannot be guaranteed to be satisfied (assuming that the future power demand is increased to 120W).

In summary, how to satisfy the power consumption requirements of the expansion device, the USB host, and the USB external device supporting the USB Type-C specification and the USB power transmission function, and simultaneously consider both the safety and the power supply benefit is an important issue to be solved urgently at present.

Disclosure of Invention

In order to solve the foregoing problems in the prior art, the present invention provides a USB expansion device with dual power sources, which includes: a first Power connection interface, which conforms to the USB Type-C and Power transmission (Power Delivery) specifications and is used for electrically connecting with a first Power supply; the second power supply connection interface is used for being electrically connected with a second power supply; the host connecting interface conforms to the USB Type-C and power transmission specifications and is used for being electrically connected with a host; the external interface is used for being electrically connected with at least one external device; the power management module is electrically connected with the first power connection interface, the second power connection interface, the host connection interface and the at least one external interface; when the first power supply connection interface and the second power supply connection interface are electrically connected with the first power supply and the second power supply respectively, the power management module enables the power of the first power supply to be provided to the host through the host connection interface corresponding to the requirement of the host on the power supply connection interface, and at the moment, the power management module enables the power of the second power supply to be provided to the power management module through the second power supply connection interface and to be provided to the at least one external device through the at least one external interface.

The invention further provides a dual-Power supply method, which is applied to a USB expansion device conforming to the USB Power transmission (Power electric) specification, wherein the USB expansion device comprises a first Power supply connection interface, a second Power supply connection interface, a host connection interface, at least one external interface and a Power supply management module, the first Power supply connection interface conforms to the USB Type-C and Power transmission specification and is electrically connected with a first Power supply, the second Power supply connection interface is electrically connected with a second Power supply, the host connection interface conforms to the USB Type-C and Power transmission specification and is electrically connected with a host, and the at least one external interface is electrically connected with at least one external device; the method comprises the following steps: communicating power supply/receiving information meeting USB Type-C and USB power transmission specifications between the first power supply and the host; providing the power of the first power supply to the host through the host connecting interface according to the power supply/receiving information; the power of the second power supply is provided to the power supply management module through the second power supply connection interface and is provided to the at least one external device through the at least one external interface; wherein the objects receiving the electric power of the first power supply and the second power supply are different.

The USB expansion device with double power supplies and the double power supply method can meet the requirements and the purposes of simultaneously supplying power to the USB expansion device, a USB host (or other devices with larger power consumption) and USB external equipment, and can also take power consumption safety and power supply benefits into consideration.

Drawings

Fig. 1 is a block diagram of a conventional single-power USB power supply system.

FIG. 2 is a block diagram of a system including a USB expansion device with dual power supplies according to a preferred embodiment of the present invention.

FIG. 3 is a block diagram of a USB expansion device with dual power supplies according to a preferred embodiment of the present invention.

FIG. 4 is a block diagram of a USB expansion device with dual power supplies according to another preferred embodiment of the present invention.

Fig. 5 is a flowchart of a dual power supply method according to an embodiment of the invention.

Fig. 6 is a flowchart of a dual power supply method according to another embodiment of the invention.

Wherein the reference numerals are:

100USB expansion device

120 power supply unit

130. 230 host

151. 152, 153, 251, 252, 253, 254 external equipment

200. 300, 400 USB expansion device with dual power supply

220 first power supply

320. 420 first power supply connection interface

240 second power supply

340. 440 second power supply connection interface

310. 410 power management module

330. 430 host connection interface

350. 450 external interface

415 power supply and demand switch and conversion unit

418 power supply and demand transaction processing unit

S510, S520, S530, S610, S620, S630, S640, S650, S660

Detailed Description

USB (Universal Serial Bus) is known for its convenience of plug and play, and relies on USB for data transmission in desktop computers, notebook computers, tablet computers, smart phones, external storage hard disks, digital cameras, printers, digital televisions, and communication and entertainment systems in automobiles, and is the most widely used transmission interface at present.

The USB can transmit data and also can supply power. Since the early USB 2.0 can only provide 2.5W, the USB 3.0 can provide 4.5W, and even the USB Power transmission (PD) 1.0 published in 7 months of 2012 greatly increases to the maximum of 100W Power (20V/5A), so far, USB Power supply can be performed on devices such as tablet computers and notebook computers, and the types of devices that can be powered are greatly expanded.

Subsequently, USB PD 2.0 specification published in 8 months 2014 first supports a new Type USB Type-C (USB3.1) non-directional connector, early USB does not provide a way to let the Power Sink (Power Sink) know the capability of the Power Source (Power Source), USB PD 2.0 specification can solve this problem, and two-way communication (Bi-phase Mark Code (BMC) of CC on-line transmission serial is performed through a specific Configuration Channel (CC) pin in USB3.1 Type-C, so that the Power role can be defined during connection of two devices, and the Power Source and the Power Sink can know the capability of the other side and cooperate with each other to determine the voltage/current value to be sent, and the USB PD 2.0 specification is independent from the conventional USB data communication Channel.

Next, the USB PD 3.0 specification published in 2016, which can support more and higher voltage types than the conventional USB Battery Charging specification (BC), particularly, the USB PD 3.0 specification adds a Programmable Power Supply (PPS) function, which allows for precise regulation of bus voltage and current, and is compatible with the fast Charging protocol of each manufacturer and can support QC 4.0 fast Charging.

The details of the USB and USB Power Delivery specifications can be found in the published specification.

Please refer to fig. 2 and fig. 3. FIG. 2 is a block diagram of a system including a USB expansion device with dual power supplies according to a preferred embodiment of the present invention. FIG. 3 is a block diagram of a USB expansion device with dual power supplies according to a preferred embodiment of the present invention.

As shown in fig. 2, the USB expansion device 200 with dual power supplies according to the preferred embodiment of the present invention is electrically connected to a first power supply 220, a second power supply 240, a host 230 and a plurality of external devices (251, 252, 253, 254). With reference to fig. 3, the USB expansion device 300 with dual power supplies is electrically connected to the first power supply 220 through a first power connection interface 320, electrically connected to the second power supply 240 through a second power connection interface 340, electrically connected to the host 230 through a host connection interface 330, and electrically connected to external devices (251, 252, 253, 254) through an external interface 350 (the external interface 350 is a schematic block, and in practice, it has four separate sub-external interfaces respectively electrically connected to the external devices (251, 252, 253, 254)).

As shown in fig. 3, a Power management module 310 of the dual-Power USB expansion device 300 according to the preferred embodiment of the present invention is electrically connected to the first Power connection interface 320, the second Power connection interface 340, the host connection interface 330 and the external connection interface 350, wherein the first Power connection interface 320 and the host connection interface 330 support USB Type-C and Power transmission (PD) specifications, that is, Configuration channels are provided in the first Power connection interface 320 and the host connection interface 330. The first power connection interface 320 and the host connection interface 330 can communicate with each other in two directions via the power management module 310 regarding the data of the power supplying/receiving voltage/current values. The host connection interface 330 may be a Power Source or a Power Sink, and in the present invention, is a Power receiving terminal.

The USB expansion device 200 with dual power supplies is, for example, a USB expansion device supporting USB power transmission standards, such as a USB Hub (Hub) or a USB docking station (DockingStation). The first power source 220 and the second power source 240 may be any power source that can provide power and support USB power transmission specifications. In one embodiment, the first power source 220 is a Direct Current (DC) power source. The host 230 is, for example, a desktop computer, a notebook computer, a tablet computer, or other devices that support the USB power transmission specification, or other devices that consume more power and support the USB power transmission specification. The invention is not limited by the above examples.

The second power connection interface 340 and the external interface 350 and the USB specification connection interface can support USB 2.0, 3.0, 3.1, etc. specifications, and in one embodiment, can also support USB Type-C and USB power transmission specifications, which is not limited by the invention.

In a preferred embodiment of the present invention, the USB expansion device 200 with dual power supplies is electrically connected to the first power supply 220 via the first power connection interface 320, and meanwhile, the USB expansion device 200 with dual power supplies is electrically connected to the second power supply 240 via the second power connection interface 340, and at this time, the host 230 is in a power receiving role and receives power. The host 230 has a USB controller and a USB connection interface (not shown) for supporting USB Type-C and USB power supply, the host 230 is electrically connected to the host connection interface 330 of the dual-power USB expansion device 200 via the USB connection interface of the host 230, and the host 230 communicates with the host connection interface 330 of the dual-power USB expansion device 200 via the USB controller of the host 230 via the USB connection interface of the host 230 for bidirectional information related to power supply/power reception. The first power source 220 performs bidirectional communication with the dual-power USB expansion device 200 via the first power connection interface 320.

In response to the host 230 requesting to provide power through the host connection interface 330, a power management module 310 provides the power of the first power source 220 to the host 230 through the host connection interface 330, and at the same time, the power management module 310 provides the power of the second power source 240 to the power management module 310 through the second power connection interface 340 and to the external device (251, 252, 253, 254) through the external interface 350. That is, the power required by the host 230 is completely supplied by the first power source 220 without being affected by the power consumption of the external devices (251, 252, 253, 254) and the dual-powered USB expansion device 200, and the external devices (251, 252, 253, 254) and the dual-powered USB expansion device 200 are additionally supplied with power by the second power source 240. That is, the power receiving object of the first power supply 220 is different from the power receiving object of the second power supply 240.

Referring to fig. 4, in further detail, referring to fig. 4, fig. 4 is a block diagram of a USB expansion device with dual power supplies according to another preferred embodiment of the present invention. A power management module 410 further includes a power supply and demand transaction processing unit 418 and a power supply and demand switch and conversion unit 415, wherein the power supply and demand transaction processing unit 418 and the power supply and demand switch and conversion unit 415 are electrically connected to each other and communicate signals. The power on demand switch and conversion unit 415 can detect the power states of a first power connection interface 420 and a host connection interface 430 and receive power state queries from the power on demand transaction unit 418. In addition, the power supply and demand switch and conversion unit 415 has Direct Current (DC) conversion and voltage regulation functions, and can open/close a power channel between the first power connection interface 420 and the host connection interface 430.

The first power connection interface 420 is electrically connected to the power supply and demand switch and conversion unit 415, and transmits the power of the first power 220 to the power supply and demand switch and conversion unit 415 via the VBUS pin in the USBType-C specification. The first power connection interface 420 includes a Configuration Channel (Configuration Channel) and can communicate with the power management module 410 and confirm the power supply. The first power connection interface 420 is electrically connected to the power on-demand transaction processing unit 418 via the CC pin of the USB Type-C specification and communicates power supply/receiving information related to the first power 220 and the host 230.

In this regard, the host connection interface 430 is electrically connected to the power supply and demand switch and the conversion unit 415, and receives power transmitted from the power supply and demand switch and the conversion unit 415 through the VBUS pin in the USBType-C specification. The power on-demand transaction processing unit 418 is electrically connected to the host connection interface 430 via the CC pin of the USB Type-C specification and communicates power supply/receiving information related to the first power source 220 and the host 230.

The second power connection interface 440 is electrically connected to the power supply and demand transaction processing unit 418 and an external interface 450, and the second power source 240 provides power to the power supply and demand transaction processing unit 418 through the second power connection interface 440 and provides power to the external device (251, 252, 253, 254) through the external interface 450.

The external interface 450 is electrically connected to the host connection interface 430, the external interface 450 and the host connection interface 430 communicate USB data signals with each other, and the external device (251, 252, 253, 254) transmits USB data signals to the host connection interface 430 through the external interface 450 and then to the host 230. On the opposite path, the host 230 transmits the USB data signal to the external interface 450 via the host connection interface 430 and then to the external device (251, 252, 253, 254).

Since power can be transmitted in both directions in USB Type-C, pre-communication is required to ensure correct voltage and directivity. The aforementioned step of "responding to the host 230 requesting power through the host connection interface 430" further comprises: through a Configuration Channel, the Power supply and demand transaction processing unit 418 queries the Power supply capability data available from the first Power supply 220 through the first Power connection interface 420 and obtains a reply from the first Power connection interface 420 (called Power Table), which includes Power scheme parameters (different bus voltage and current data) that can be provided through the first Power connection interface 420), the host 230 queries the available Power supply capability data through the host connection interface 430, and the Power supply and demand transaction processing unit 418 replies to the host 230 through the host connection interface 430 with the Power Table. According to the power supply table returned by the power supply and demand transaction processing unit 418, the host 230 provides the required power supply through the host connection interface 430.

The aforementioned step of the power management module 410 providing the power of the first power source 220 to the host 230 through the host connection interface 430 further includes: through the Configuration Channel, the power on demand transaction unit 418 proposes the required power of the host 230 through the host connection interface 430 to the first power connection interface 420, the first power supply 220 receives the power required by the host 230 through the first power connection interface 420 and modifies the bus voltage to the corresponding parameter, after the power supply/demand transaction processing unit 418 checks that the power supply is correct, it notifies the power supply/demand switch and conversion unit 415 to start the power transmission channel between the first power connection interface 420 and the host connection interface 430 (the power supply/demand switch and conversion unit 415 can further perform voltage adjustment), such that the power of the first power source 220 is provided to the host 230 through the VBUS pin of the USB Type-C of the first power source connection interface 420 and the VBUS pin of the USB Type-C of the host connection interface 430. At this time, the power of the first power 220 from the first power connection interface 420 is only provided to the host 230. The above-mentioned inquiry communication and the required flexible power supply mode provide an effective power supply mode to avoid unnecessary energy consumption.

The present invention provides a dual Power supply method, which is applied to a USB expansion device conforming to the USB Power transmission (Power Delivery) specification, as shown in fig. 2, the USB expansion device 200 with dual Power supplies is electrically connected to the first Power supply 220, the second Power supply 240, the host 230, and the external devices (251, 252, 253, 254). With reference to fig. 3, the dual-power USB expansion device 300 includes the first power connection interface 320, the second power connection interface 340, the host connection interface 330, the external interface 350, and the power management module 310. The USB expansion device 300 with dual power supplies is electrically connected to the first power supply 220 through the first power connection interface 320, the second power supply 240 through the second power connection interface 340, the host 230 through the host connection interface 330, and the external devices (251, 252, 253, 254) through the external interface 350 (the external interface 350 is a schematic block, and in practice, it has four separate sub-external interfaces electrically connected to the external devices (251, 252, 253, 254). For further description of fig. 2 and 3, reference is made to the foregoing description.

Referring to fig. 5, fig. 5 is a flowchart of a dual power supply method according to an embodiment of the invention. The dual-power supply method comprises the following steps: step S510: communicate power supplying/receiving information conforming to USB Type-C and USB power transmission specifications between the first power source 220 and the host 230; subsequently, step S520: providing the power of the first power source 220 to the host 230 through the host connection interface 330 according to the power supply/receiving information; then, step S530: the power of the second power source 240 is provided to the power management module 310 through the second power connection interface 340 and provided to the external devices (251, 252, 253, 254) through the external interface 350; the objects receiving the power of the first power source 220 and the second power source 240 are different.

In more detail, referring to fig. 4, the power management module 410 further includes the power supply and demand transaction processing unit 418 and the power supply and demand switch and conversion unit 415. The power on demand switch and conversion unit 415 can detect the power states of the first power connection interface 420 and the host connection interface 430 and accept the power state query of the power on demand transaction unit 418. In addition, the power supply and demand switch and conversion unit 415 has Direct Current (DC) conversion and voltage regulation functions, and can open/close a power channel between the first power connection interface 420 and the host connection interface 430. The first power connection interface 420 includes a Configuration Channel (Configuration Channel) for communicating with the power management module 410 and determining power supply. For other descriptions related to fig. 4, reference is made to the foregoing description, and further description is not repeated herein. Referring to fig. 6, fig. 6 is a flowchart of a dual power supply method according to another embodiment of the invention. Wherein, the step S510 of communicating the power supplying/receiving information meeting the USB Type-C and USB power transmission specifications between the first power source 220 and the host 230 further comprises: step S610: the power supply and demand transaction processing unit 418 queries the power supply of the first power supply 220 through the first power connection interface 420 and gets a reply; step S620: the host 230 inquires about the power supply through the host connection interface 430, and the power supply and demand transaction processing unit 418 replies to the power supply of the host 230 through the host connection interface 430; step S630: the host 230 provides the required power via the host connection interface 430 according to the power recovered by the power on demand transaction unit 418. The step S520 of providing the power of the first power source 220 to the host 230 through the host connection interface 430 according to the power supplying/receiving information further includes: step S640: the power on demand transaction unit 418 provides the first power connection interface 420 with the power required by the host 230 via the host connection interface 430; step S650: the power on demand transaction processing unit 418 notifies the power on demand switch and conversion unit 415 to start the power transmission channel between the first power connection interface 420 and the host connection interface 430; step S660: the power of the first power source 220 is provided to the host 230 through the host connection interface 430.

In summary, the USB expansion device with dual power sources, which is composed of the power management module supporting the USB power transmission specification and the connection interface of the present invention, enables the first power source to efficiently supply power to the host (or other devices requiring larger power supply), the second power source to supply power to the USB expansion device and the external device, and the dual power sources can respectively provide power to different power receiving objects, thereby achieving the purpose of satisfying the power consumption requirement, power consumption safety and power supply benefit of the power receiving device.