Universal serial bus (USB) hub having a plurality of input power sources

Claim 2

A universal serial bus (USB) hub having a plurality of input power sources including a power source connected through an upstream cable and a local power source unit, wherein power from said plurality of input power sources is selectively used as internal consumption power of the USB hub and as power distributed to satisfy at least one USB function through at least one downstream port; wherein said USB hub includes a hub controller and a power source interface for receiving as inputs both bus power provided through the upstream cable and self-power generated by said local power source unit, and wherein the self-power is supplied to and used be the USB hub controller when the user connects an additional power source cable to the USB hub, and wherein the bus power is supplied to and used by the USB hub controller when the user does not connect the additional power source cable to the USB hub.

Claim 3

The USB hub as claimed in claim 1 , wherein the power source interface is disposed between the upstream cable and the local power source unit.

Claim 4

The USB hub as claimed in claim 2 , wherein the power source interface includes: power source transmitting means for transmitting the bus power to an output terminal without additional voltage step-down; and reverse-current preventing means for preventing self-power from flowing to the upstream cable.

Claim 5

The USB hub as claimed in claim 3 , wherein said power source transmitting means comprises a common base transistor circuit including an emitter terminal and a base terminal, and wherein said reverse-current preventing means is connected between the emitter terminal and the base terminal.

Claim 6

The USB hub as claimed in claim 4 , wherein said reverse-current preventing means comprises a diode.

Claim 7

The USB hub as claimed in claim 4 , wherein the bus power is supplied to the emitter terminal, and is supplied to the base terminal through the reverse-current preventing means and a bias resistance; and wherein a junction between the bias resistance and the base terminal is grounded through a further resistance, and the transistor has a collector terminal connected to the local power source unit and to said at least one downstream port.

Claim 8

The USB hub as claimed in claim 6 , wherein said at least one downstream port includes a current limit circuit having an input connected to the collector terminal and an output connected to at least one downstream bus.

Claim 9

The USB hub as claimed in claim 7 , wherein the collector terminal is connected to an input of a regulator which has an output for performing at least one internal function.

Claim 10

The USB hub as claimed in claim 6 , wherein the collector terminal is connected to an input of a regulator which has an output for performing at least one internal function.

Claim 11

A universal serial bus (USB) hub for selectively utilizing power from an upstream bus and a local power source, said USB hub comprising: power source interface means connected to the upstream bus for receiving the power therefrom, and for providing a power output; and current limiting means connected to the local power source for receiving the power therefrom, and connected to the power source interface means for receiving the power output therefrom, said current limiting means providing a current limited output; wherein the power output of said power source interface means is used to execute internal functions of the USB hub, and the current limited output of said current limiting means is provided to a downstream bus to control external functions.

Claim 12

A universal serial bus (USB) hub for selectively utilizing power from an upstream bus and a local power source, said USB hub comprising: power source interface means connected to the upstream bus for receiving the power therefrom, and for providing a power output; and current limiting means connected to the local power source for receiving the power therefrom, and connected to the power source interface means for receiving the power output therefrom, said current limiting means providing a current limited output; wherein the power output of said power source interface means is used to execute internal functions of the USB hub, and the current limited output of said current limiting means is provided to a downstream bus to control external functions.

Claim 13

The USB hub as claimed in claim 10 , wherein self-power is supplied to the USB hub in dependence on a user connecting a power source cable from the local power source to the USB hub.

Claim 14

The USB hub as claimed in claim 10 , wherein said power source interface means is disposed between the upstream bus and the local power source.

Claim 15

The USB hub as claimed in claim 12 , wherein said power source interface means includes: a power source transmitter for transmitting the bus power to an output terminal without additional voltage step-down; and a reverse-current prevention device for preventing self-power from the local power source from flowing to the upstream bus.

Claim 16

The USB hub as claimed in claim 13 , wherein said power source transmitter comprises a common base transistor circuit including an emitter terminal and a base terminal, and wherein the reverse-current prevention device is connected between the emitter terminal and the base terminal.

Claim 17

The USB hub as claimed in claim 14 , wherein the reverse-current prevention device comprises a diode.

Claim 18

The USB hub as claimed in claim 14 , wherein the bus power is supplied to the emitter terminal, and is supplied to the base terminal through the reverse-current prevention device and a bias resistance; and wherein a junction between the bias resistance and the base terminal is grounded through a further resistance, and the transistor has a collector terminal connected to the local power source unit and to at least one of said current limiting means and a regulator.

Claim 19

The USB hub as claimed in claim 16 , wherein said current limiting means has an input connected to the collector terminal and an output connected to at least one downstream bus.

Claim 20

The USB hub as claimed in claim 17 , wherein the collector terminal is connected to an input of said regulator, and said regulator has an output for performing at least one internal function.

Claim 21

The USB hub as claimed in claim 16 , wherein the collector terminal is connected to an input of said regulator, and said regulator has an output for performing at least one internal function.

Claim 22

A universal serial bus (USB) hub having a plurality of input power sources including a power source connected through an upstream cable and a local power source unit, wherein power from said plurality of input power sources is selectively used as internal consumption power of the USB hub and as power distributed to satisfy at least one USB function through at least one downstream port; wherein said USB hub includes a power source interface for inputting both bus power provided through the upstream cable and self-power generated by said local power source unit, and wherein the self-power is supplied to the USB hub in dependence on the user connecting an additional power source cable to the USB hub; wherein the power source interface is disposed between the upstream cable and the local power source unit; and wherein the power source interface includes: power source transmitting means for transmitting the bus power to an output terminal without additional voltage step-down; and reverse-current preventing means for preventing self-power from flowing to the upstream cable.

Claim 23

A universal serial bus (USB) hub having a plurality of input power sources including a power source connected through an upstream cable and a local power source unit, wherein power from said plurality of input power sources is selectively used as internal consumption power of the USB hub and as power distributed to satisfy at least one USB function through at least one downstream port; wherein said USB hub includes a power source interface for inputting both bus power provided through the upstream cable and self-power generated by said local power source unit, and wherein the self-power is supplied to the USB hub in dependence on the user connecting an additional power source cable to the USB hub; wherein the power source interface is disposed between the upstream cable and the local power source unit; and wherein the power source interface includes: power source transmitting means for transmitting the bus power to an output terminal without additional voltage step-down; and reverse-current preventing means for preventing self-power from flowing to the upstream cable.

Claim 24

The USB hub as claimed in claim 20 , wherein said power source transmitting means comprises a common base transistor circuit including an emitter terminal and a base terminal, and wherein said reverse-current preventing means is connected between the emitter terminal and the base terminal.

Claim 25

The USB hub as claimed in claim 21 , wherein said reverse-current preventing means comprises a diode.

Claim 26

The USB hub as claimed in claim 21 , wherein the bus power is supplied to the emitter terminal, and is supplied to the base terminal through the reverse-current preventing means and a bias resistance; and wherein a junction between the bias resistance and the base terminal is grounded through a further resistance, and the transistor has a collector terminal connected to the local power source unit and to said at least one downstream port.

Claim 27

The USB hub as claimed in claim 23 , wherein said at least one downstream port includes a current limit circuit having an input connected to the collector terminal and an output connected to at least one downstream bus.

Claim 28

The USB hub as claimed in claim 24 , wherein the collector terminal is connected to an input of a regulator which has an output for performing at least one internal function.

Claim 29

The USB hub as claimed in claim 23 , wherein the collector terminal is connected to an input of a regulator which has an output for performing at least one internal function.