TW201728023A - USB hub with low power consumption - Google Patents

Abstract

A USB hub includes an upstream port, a plurality of downstream ports, and a control unit. When it is determined that the upstream port is not occupied, or that the upstream port is occupied but all downstream ports are not occupied, the control unit is configured to operate the USB hub in a first mode. When it is determined that the upstream port is occupied and at least one downstream port is occupied, the control unit is configured to operate the USB hub in a second mode. The USB hub consumes less power when operating in the first mode than when operating in the second mode.

Description

Low-energy universal sequence bus hub

The present invention relates to a general-purpose serial bus hub, and more particularly to a low-energy general-purpose serial bus hub.

The universal serial bus (USB) is a very popular computer interface connection standard and a technical specification for input and output interfaces. The general computer system will provide at least one standard USB port. Any peripheral device that conforms to the USB standard can be connected to any computer system with USB standard specifications, and then the data can be transmitted to each other by USB digital signals. Plug and play (PNP), which means that all kinds of peripheral devices can be placed at any time without rebooting or installing. Since the computer system can only provide a limited number of USB ports, not all peripheral devices can be connected to the computer system in a one-to-one manner at the same time. Therefore, USB hubs have been developed on the market, which enable computer systems to transmit data to and from multiple peripheral devices through a single USB port.

A conventional USB hub generally has an upstream port to connect to the host, and a plurality of downstream ports to connect to one or more peripheral devices, so that the host can simultaneously and multiple through the USB hub. The peripheral devices remain connected and operate. To save power, the current USB communication specification determines the mode of operation of the USB hub for whether it is connected to the host. When the upstream port is occupied by the host, the USB hub will supply power to all downstream ports to operate in the normal mode; when the upstream port is not occupied by the host, the USB hub will stop supplying power to the downstream port in the power saving mode. Under work.

Usually the user will connect the USB hub to the host for a long time, but the peripheral device will be plugged into the downstream end of the USB hub only when it is to be used. In this case, when the upstream port is occupied by the host, even if the host does not transmit data with any peripheral devices, the prior art USB hub will continue to supply power to the downstream port, thus increasing the unnecessary consumption of the USB hub. Electricity.

The present invention provides a USB hub including an upstream port, at least a first downstream port, and a control unit. The first downstream port includes a first data pin and a second data pin for transmitting data to or receiving data from the device when the first downstream port is occupied by a device; and a voltage A pin and a ground pin are used to transmit a power source to the device when the first downstream port is occupied by the device, wherein the ground pin is floating. The control unit is coupled to the ground pin of the upstream end and the first downstream end to determine whether the upstream port and the first downstream port are occupied; when it is determined that the upstream port is occupied but Controlling the USB hub to operate in a first mode when the first downstream port is not occupied; and controlling the USB hub to be in a state when it is determined that both the upstream port and the first downstream port are occupied The second mode operates, wherein the power consumption of the USB hub when operating in the first mode is lower than the power consumption when operating in the second mode.

The present invention further provides a method of operating a USB hub, the USB hub including an upstream port, at least one downstream port, and a control unit. The method includes: setting a ground pin of the downstream end to be floated, such that when the downstream end is occupied, the ground pin has a first potential; and when the downstream end is unoccupied, The grounding pin has a second potential; the control unit determines whether the upstream terminal is occupied; the control unit determines whether the downstream terminal is occupied according to the potential detected from the grounding pin; when determining the upstream When the port is occupied but the downstream port is not occupied, the control unit controls the USB hub to operate in a first mode; and when it is determined that both the upstream port and the downstream port are occupied, the control unit The USB hub is controlled to operate in a second mode, wherein the power consumption of the USB hub when operating in the first mode is lower than the power consumption when operating in the second mode.

The invention further provides a display comprising a screen and a USB hub. The USB hub includes an upstream port, at least a first downstream port, and a control unit. The first downstream port includes a first data pin and a second data pin for transmitting data to or receiving data from the device when the first downstream port is occupied by a device; and a voltage A pin and a ground pin are used to transmit a power source to the device when the first downstream port is occupied by the device, wherein the ground pin is floating. The control unit is coupled to the ground pin of the upstream end and the first downstream end to determine whether the upstream port and the first downstream port are occupied; when it is determined that the upstream port is occupied but Controlling the USB hub to operate in a first mode when the first downstream port is not occupied; and controlling the USB hub to be in a state when it is determined that both the upstream port and the first downstream port are occupied The second mode operates, wherein the power consumption of the USB hub when operating in the first mode is lower than the power consumption when operating in the second mode.

FIG. 1 is a functional block diagram of a display 150 in an embodiment of the present invention. Display 150 includes a screen 50 and a USB hub 100. In the embodiment of the present invention, the display 150 can be any device having a display function and having a USB standard specification. However, the type of display 150 does not limit the scope of the invention.

The USB hub 100 includes an upstream port 埠UP, a plurality of downstream ports DN ₁ DN DN _M , and a control unit 10, where M is a positive integer. The USB hub 100 can be connected to a host via an upstream port 埠UP and/or to one or more peripheral devices via downstream ports DN ₁ DN DN _M. In an embodiment of the invention, the USB hub 100 can be connected to any device providing at least one standard USB port via an upstream port. However, the type of the host does not limit the scope of the present invention.

In the embodiment of the present invention, the USB hub 100 can be connected to one or more devices conforming to the USB standard specification through the downstream ports DN ₁ DN DN _M , such as a printer, a microphone, a loudspeaker, a screen, a mouse, a keyboard. , action hard drive, or memory card. However, the type of peripheral device does not limit the scope of the present invention.

FIG. 2 is a schematic diagram of the upstream end 埠UP in the USB hub 100 of the present invention. The upstream port 埠UP includes a first data pin DATA+, a second data pin DATA-, a voltage pin VCC, and a ground pin GND. When the upstream port 埠UP is occupied by the host, the USB hub 100 can transmit data to and from the host through the first data pin DATA+ and the second data pin DATA-. The voltage pin VCC is coupled to the control unit 10, and the ground pin GND is coupled to a reference ground potential. Since the upstream terminal 埠UP is occupied by the host, the potential of the voltage pin VCC is changed, and the control unit 10 can determine whether the USB hub 100 is connected to the host.

3 is a schematic diagram of the downstream ports DN ₁ DN DN _M of the USB hub 100 of the present invention. The downstream ports DN ₁ DN DN _M each include a first data pin (represented by DATA ₁ + DATA _M + respectively) and a second data pin (represented by DATA ₁ - DATA _M - respectively), A voltage pin (represented by VCC ₁ to VCC _M , respectively), and a ground pin (represented by GND ₁ to GND _M , respectively). When a downstream port is occupied by a peripheral device, the USB hub 100 can transmit data to or receive data from the peripheral device through the corresponding first data pin and the second data pin, and through the corresponding voltage pin. Transfer power to the peripherals. Each of the ground pins GND ₁ GND _{M is} coupled to the control unit 10 and is a floating potential such that when a downstream terminal is occupied, the corresponding ground pin has a first potential, and a downstream end When the 埠 is unoccupied, its corresponding ground pin will have a second potential. Therefore, the control unit 10 can judge whether the USB hub 100 is connected to any peripheral device.

In the embodiment shown in FIG. 3, the ground pins GND ₁ GND GND _M of the downstream terminals DN ₁ DN DN _M can be coupled to a bias voltage V _BIAS through a resistor R to form a floating circuit. However, the structure of the floating circuit does not limit the scope of the present invention.

The control unit 10 can control the operation mode of the USB hub 100. FIG. 4 is a flow chart of the operation of the control unit 10 in the embodiment of the present invention, which includes the following steps:

Step 410: Detect the potential of the voltage pin VCC in the upstream end 埠 UP and the potential of the ground pins GND ₁ GND GND _M in the downstream end 埠 DN ₁ DN DN _M ;

Step 420: Determine whether the upstream terminal 埠UP is occupied according to the potential of the voltage pin VCC in the upstream terminal 埠UP: if yes, go to step 430; if no, go to step 440.

Step 430: the downstream end of the port based on the potential DN ₁ ~DN _M in the ground pin GND ₁ ~GND _M to determine whether at least a downstream end of a particular port is occupied: if yes, perform step 450; if not, step 440 is executed.

Step 440: Control the USB hub to operate in a first mode, and perform step 410.

Step 450: Control the USB hub to operate in a second mode, and perform step 460.

Step 460: Monitor whether the upstream port 埠UP and the specific downstream port 维持 are all occupied. If yes, go to step 450; if no, go to step 440.

In the embodiment shown in FIG. 4, the first mode is the power saving mode, at which time the USB hub 100 stops supplying power to the downstream ports DN ₁ DN DN _M ; the second mode is the normal mode, and the USB hub 100 at this time Power is supplied to the downstream terminal 埠DN ₁ ~DN _M . The following chart 1 shows various scenarios in which the control unit 10 controls the mode of operation of the USB hub 100. Chart one

In steps 410-430, when it is determined that the USB hub 100 is not connected to the host, or when it is determined that the USB hub 100 is connected to the host but is not connected to any peripheral device, the present invention performs step 440 to control the USB hub 100. In a mode (power saving mode), when it is determined that the USB hub 100 is connected to the host and the at least one peripheral device, the present invention performs step 450 to control the USB hub 100 to operate in the second mode (normal mode). Therefore, the USB hub 100 of the present invention supplies power to the downstream ports DN ₁ DN DN _M only when the host is connected to at least one peripheral device through the USB hub 100, thereby reducing the unnecessary power consumption of the USB hub.

In addition, during the period of power supply to the downstream ports DN ₁ DN DN _M , the present invention also periodically monitors in step 460 whether the upstream port 埠 UP and at least one downstream port 维持 are maintained occupied. Once it is detected that all downstream ports become unoccupied, the USB hub 100 will perform step 440 to switch to the power saving mode. Therefore, the USB hub 100 of the present invention supplies power to the downstream ports DN ₁ DN DN _M only when the host is connected to at least one peripheral device through the USB hub 100, thereby reducing the unnecessary power consumption of the USB hub. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10‧‧‧Control unit
50‧‧‧ screen
100‧‧‧USB hub
150‧‧‧ display
R‧‧‧resistance
V _BIAS ‧‧‧ bias
UP‧‧‧Upstream end
DN ₁ ~ DN _M ‧‧‧ downstream end 埠
DATA+, DATA ₁ +~DATA _M +‧‧‧First data pin
DATA-, DATA _{1 -} ~DATA _M -‧‧‧Second data pin
VCC, VCC ₁ ~ VCC _M ‧‧‧ voltage pin
GND, GND ₁ ~ GND _M ‧‧‧ Grounding Pin
410~460‧‧‧Steps

FIG. 1 is a functional block diagram of a display in an embodiment of the present invention. Figure 2 is a schematic diagram of the upstream end of the USB hub of the present invention. Figure 3 is a schematic diagram of the downstream end of the USB hub of the present invention. Figure 4 is a flow chart showing the operation of the control unit of the USB hub in the embodiment of the present invention.

410~460‧‧‧Steps

Claims (12)

A universal serial bus (USB) hub includes: an upstream port; at least one first downstream port, comprising: a first data pin and a second data a pin for transmitting data to or receiving data from the device when the first downstream port is occupied by a device; and a voltage pin and a ground pin for being used at the first downstream end The device is configured to transmit a power source to the device, wherein the ground pin is floating; and a control unit coupled to the ground pin of the upstream port and the first downstream port for determining: Whether the upstream port and the first downstream port are occupied; when it is determined that the upstream port is occupied but the first downstream port is not occupied, controlling the USB hub to operate in a first mode; When the upstream port and the first downstream port are occupied, controlling the USB hub to operate in a second mode, wherein the power consumption of the USB hub in the first mode is lower than in the second mode Work in mode . The USB hub of claim 1, wherein the control unit is further configured to: stop power supply to the first downstream port to control the USB hub to operate in the first mode; and supply power to the first downstream port The USB hub is controlled to operate in the second mode. The USB hub of claim 2, wherein the control unit is further configured to: monitor whether the upstream port and the first downstream port are both occupied during power supply to the first downstream port; and When it is monitored that at least one of the upstream port and the first downstream port is unoccupied, power supply to the first downstream port is stopped. The USB hub of claim 1, further comprising one or more second downstream ports, wherein the control unit is further configured to: determine whether the one or more second downstream ports are occupied; and when determining Controlling the USB hub to operate in the first mode when the upstream port is occupied and determining that the first downstream port and the one or more second downstream ports are unoccupied; and when determining the upstream end When the UI is occupied and it is determined that at least one of the one or more second downstream ports is occupied, the USB hub is controlled to operate in the second mode. The USB hub of claim 1, wherein the ground pin is coupled to a bias voltage through a resistor to form a floating circuit. The USB hub of claim 5, wherein: the ground pin has a first potential when the first downstream port is occupied; and the ground pin is provided when the first downstream port is not occupied a second potential; and the determining circuit determines whether the first downstream port is occupied according to the potential detected from the ground pin. A method of operating a USB hub, the USB hub includes an upstream port, at least one downstream port, and a control unit, the method comprising: setting a ground pin of the downstream port to be floating, such that: When the downstream port is occupied, the ground pin has a first potential; and when the downstream port is unoccupied, the ground pin has a second potential; the control unit determines whether the upstream port is occupied The control unit determines whether the downstream port is occupied according to the potential detected from the ground pin; when it is determined that the upstream port is occupied but the downstream port is not occupied, the control unit controls the USB hub Operating in a first mode; and when it is determined that both the upstream port and the downstream port are occupied, the control unit controls the USB hub to operate in a second mode, wherein the USB hub is at the first The power consumption when operating in mode is lower than the power consumption when operating in the second mode. The method of claim 7, further comprising: the control unit causing a power supply to be stopped to be supplied to the downstream port, thereby controlling the USB hub to operate in the first mode; and the control unit allowing the power source to be Supply to the downstream port, thereby controlling the USB hub to operate in the second mode. The method of claim 8, further comprising: monitoring whether the upstream port and the downstream port are both occupied while the power source is being supplied to the downstream port; and when monitoring the upstream port And when at least one of the downstream ports is unoccupied, the control unit stops the power supply from being supplied to the downstream port. A display comprising: a screen; and a USB hub comprising: an upstream port; at least one first downstream port, comprising: a first data pin and a second data pin for The first downstream port is configured to transmit data to or receive data from the device when occupied by a device; and a voltage pin and a ground pin for transmitting when the first downstream port is occupied by the device a power supply to the device, wherein the grounding pin is floating; and a control unit coupled to the grounding pin of the upstream end and the first downstream end for determining: the upstream end and the first Whether a downstream port is occupied; when it is determined that the upstream port is occupied but the first downstream port is not occupied, controlling the USB hub to operate in a first mode; and when determining the upstream port and the When the first downstream port is occupied, the USB hub is controlled to operate in a second mode, wherein the power consumption of the USB hub when operating in the first mode is lower than when operating in the second mode Consumption. The display of claim 10, wherein the control unit is further configured to: stop power supply to the first downstream port to control the USB hub to operate in the first mode; and supply power to the first downstream port to control The USB hub operates in the second mode. The display device of claim 10, wherein: the grounding pin is coupled to a bias voltage through a resistor to form a floating circuit; when the first downstream terminal is occupied, the grounding pin has a first a potential; the ground pin has a second potential when the first downstream end is not occupied; and the determining circuit determines whether the first downstream end is based on the potential detected from the ground pin Occupied.