A USB hub utilizes an external power supply connection and rechargeable battery to provide a fully functional USB hub that provides portable backup power for USB devices. The hub includes a housing with a host connector that is adapted to be coupled to a host. Device connectors are also positioned on the housing that are adapted to be coupled to electronic devices. A hub circuit enables USB communications between the devices and host connected to the hub. The rechargeable battery is selectively charged from the host or external power supply connection. A microcontroller controls the hub circuitry such that power is provided to the hub circuit and the device connectors from an external power source or host if available or the rechargeable battery if they are not.
1. A power hub comprising:
a housing;
a host connector positioned on said housing wherein said host connector is adapted to be coupled to a host device and receive a host power supply voltage from said host device;
at least two device connectors positioned on said housing wherein each of said device connector is adapted to be coupled to an electronic device and provide a power supply voltage to said electronic device;
a rechargeable battery in said housing;
a hub circuit that connects both of said device connectors to said host connector such that a host device connected to said host connector can communicate digital data with an electronic device connected to one of said device connectors;
a microcontroller that controls said hub such that power for said hub circuit, rechargeable battery and device connectors is provided from a host device if a host device is connected to the host connector and power for an electronic device connected to one of said device connectors is provided from said rechargeable battery if no host is connected to the host connector; and
a battery bypass circuit for bypassing said rechargeable battery if a charge level of said rechargeable battery falls below a threshold level and no external power is available;
wherein said rechargeable battery is charged from a host device connected to said host connector only when a power current drawn by any electronic devices connected to said device connectors is below a specified threshold.
2. The power hub of claim 1 further comprising an external power supply connection wherein said microcontroller uses said external power supply connection to power said hub circuit, recharge said rechargeable battery and power any said electronic devices coupled to said device connectors when said external power supply connection is connected to an external power supply.
3. The power hub of claim 1 wherein said host connector and device connectors further comprise USB connectors.
4. The power hub of claim 1 wherein said microcontroller charges said rechargeable battery when said microcontroller detects that said power hub has been connected to an external power supply or a host device.
5. The power hub of claim 1 wherein said housing further comprises an upper housing and a lower housing mounted on a central frame.
6. A hub for connecting a host device to a plurality of downstream devices, said hub comprising:
a rechargeable power supply;
a host connector adapted to couple to said host device;
at least two device connectors each adapted to couple to a downstream device;
a battery bypass circuit for bypassing said rechargeable battery when a current drawn by a downstream device exceeds a current threshold; and
a battery bypass circuit for bypassing said rechargeable battery if a charge level of said rechargeable battery falls below a threshold level and no external power is available;
wherein said rechargeable power supply is recharged when a host is connected to the host, connector and wherein said rechargeable power supply can supply power to a downstream device when a host is not connected to said host connector.
7. The hub of claim 6 wherein said host and device connectors are USB connectors.
8. The hub of claim 6 further comprising a boost converter for converting a battery voltage into a downstream device voltage.
9. The hub of claim 6 further comprising an external power supply connection.
10. The hub of claim 9 wherein said hub charges said rechargeable battery and powers said downstream devices with power from said external power supply connection when external power is available.
11. The hub of claim 6 further comprising an LED display and button wherein said LED display displays a charge level for said rechargeable battery when said button is pressed.
12. A method of operating a hub having a host connector, at least two device connectors, a rechargeable battery and an external power supply connection contained in a housing, said method comprising:
detecting if external power is available from said external power supply connection and, if external power is available, powering said hub, charging said rechargeable battery and powering any devices connected to said device connectors with said external power;
if no external power is available, detecting if host power is available from said host connector and, if host power is available, powering said hub, charging said rechargeable battery and powering any devices connected to said device connectors with said host power;
monitoring a current level provided to downstream devices connected to said device connectors by said hub and stopping charging of said rechargeable battery when said current level exceeds a threshold level;
if no external power or host power is available, powering said hub and any devices connected to said device connectors with said rechargeable battery; and
placing said hub into a sleep mode whereby said rechargeable battery is disconnected from said hub if a charge level of said rechargeable battery falls below a threshold level and no external, power or host power is available.
13. The method of claim 12 further comprising the step of enabling digital communications between a host connected to said host connector and at least two devices connected to said device connectors.
14. The method of claim 12 wherein said device connectors and said host connector further comprise USB connectors.
15. The method of claim 12 further comprising the step of enabling USB digital communications between a host connected to said host connector and at least two devices connected to said device connectors.
16. The method of claim 12 further comprising the step of displaying a charge level of said rechargeable battery in response to a user input.