Powering a notebook across a USB interface

• US 20040064621A1
• Filed: 09/30/2003
• Published: 04/01/2004
• Est. Priority Date: 06/30/2000
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Sawyers, Thomas P., Stufflebeam, Kenneth W., Dougherty, Michael J., Lakdawala, Rahul V.
• Granted Patent: US 7,360,004 B2
• Time in Patent Office: Days
• US Class Current: 710/303
• CPC Class Codes: G06F 1/1632 External expansion units, e.g. docking stations
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips

Abstract

A laptop computer and mating docking station where the docking station provides power to the laptop computer over power rails of the Universal Serial Bus (USB) interface. The laptop computer has laptop docking logic that both provides power in accordance with standard USB protocol, and also receiving power across the power rails of the USB interface. Likewise, the docking station has a docking station dock logic that establishes communication with the laptop docking logic across the USB power rails. Once positive communication is established, the dock station provides voltages on the USB power rails sufficient to power the laptop computer as well as charge the laptop'"'"'s battery.

Claims

1. A computer system, comprising:

a self powered device;

a laptop computer coupled to said self powered device by way of a communication bus; and

said laptop computer powered by said self powered device across power lines of said communication bus.

2. The computer system as defined in claim 1 further comprising:

said self powered device comprises a docking station;

said laptop computer comprising;

a processor;

a system memory coupled to said processor by way of a host bridge device;

a second bridge device coupled to said host bridge device by way of a primary expansion bus, said second bridge device adapted to communicate over said communication bus being a Universal Serial Bus (USB) interface;

a system battery coupled to said processor and bridge devices; and

a laptop docking logic coupled to said system battery and power rails of said USB interface, said laptop docking logic adapted to couple power from said USB power rails to said system battery; and

said docking station comprising a dock station docking logic adapted to determine whether said laptop computer is capable of receiving power across said USB interface, said dock station docking logic further adapted to provide power to said laptop on said power rails of said USB interface.

3. The computer system as defined in claim 2 wherein said laptop docking logic further comprises:

a voltage control unit coupled to said USB power rails and said system battery, said voltage control unit adapted to couple power from said USB power rails; and

a signaling circuit coupled to said USB power rails, said signaling circuit adapted to respond to communication signals on said power rails to identify said laptop as being capable of receiving power on said USB power rails.

4. The computer system as defined in claim 3 wherein said voltage control unit further comprises:

a five volt supply input signal, said voltage control unit adapted to selectively couple said five volt supply input signal to said positive power rail; and

a shut off input signal, said voltage control unit adapted to de-couple said five volt supply input signal from a positive power rail responsive to assertion of said shut off signal.

5. The computer system as defined in claim 3 wherein said signaling circuit further comprises:

a line powered serial communication device coupled across said USB power rails, said communication device adapted to respond to communication signals to identify said laptop computer as capable of receiving power across said USB power rails; and

coupling current logic coupled across said USB power rails adapted to draw a current across said USB power rails to indicate the presence of a laptop computer capable of receiving power across said USB power rails.

6. The computer system as defined in claim 5 wherein said line powered serial communication device further comprises a Dallas Semiconductor device DS2401.

7. The computer system as defined in claim 2 wherein said dock station docking logic further comprises:

a communication and control logic coupled to said USB power rails adapted to serially communicate over said USB power rails;

a current sense logic adapted to sense current flowing from the docking station to the laptop computer; and

a voltage ramp logic adapted to selectively supply power to said laptop across said USB power rails.

8. The computer system as defined in claim 7 wherein said communication and control logic further comprises a Programmable Array Logic (PAL) configured to operate as a state-machine.

9. The computer system as defined in claim 7 further comprising:

said current sense logic adapted to generate a shut-off signal when current flow from said docking station to said laptop falls below a predefined minimum; and

said communication and control logic coupled to said shut-off signal and adapted to turn off power supplied from said docking station to said laptop computer responsive to assertion of said shut-off signal.

10. In a computer system comprising a laptop computer adapted to dock to a docking station by way of a communication bus, a method of operating said computer system comprising:

powering said laptop computer from said docking station across said USB interface.

11. The method as defined in claim 10 further comprising:

coupling an operating laptop computer to said docking station;

communicating over serial communication lines of said communication bus;

determining that said docking station is capable of supply power across said communication bus;

discontinuing application of voltage to power lines of said communication bus by said laptop computer; and

providing power on said power lines of said communication bus by said docking station.

12. The method as defined in claim 11 wherein said communication bus is a Universal Serial Bus.

13. The method as defined in claim 10 further comprising:

coupling a laptop computer to said docking station by way of said communication bus;

communicating over power signal lines of said communication bus;

determining that said laptop is capable of receiving power over said power signal lines of said communication bus; and

providing power on said power signal lines of said communication bus by said docking station.

14. The method as defined in claim 13 wherein said communication bus is a Universal Serial Bus.

15. A computer comprising:

a processor;

a system memory coupled to said processor;

a bridge device coupled to said processor, said bridge device having a Universal Serial Bus (USB) interface;

a system battery coupled to said processor and bridge devices; and

a docking logic coupled to said system battery and power rails of said USB interface, said docking logic adapted to couple power from said USB power rails to said system battery.

16. The laptop computer as defined in claim 15 wherein said docking logic further comprises:

a voltage control unit coupled to said USB power rails and said system battery, said voltage control unit adapted to selectively provide power to said USB power rails; and

a signaling circuit coupled to said USB power rails, said signaling circuit adapted to respond to communication signals on said USB power rails to identify said laptop as capable of receiving power on said USB power rails.

17. The laptop computer as defined in claim 16 wherein said voltage control unit further comprises:

a five volt supply input signal, said voltage control unit adapted to selectively couple said five volt supply input signal to a positive power rail; and

a shut-off input signal, said voltage control unit adapted to de-couple said five volt supply input signal from said positive power rail responsive to assertion of said shut-off signal.

18. The laptop computer as defined in claim 16 wherein said signaling circuit further comprises:

a line powered serial communication device coupled across said USB power rails, said communication device adapted to respond to communication signals on said positive power rail to identify said laptop computer as capable of receiving power across said USB power rails; and

a coupling current logic coupled across said USB power rails adapted to draw a current from said USB power rails when a voltage on said USB power rails exceeds a threshold voltage.

19. The laptop computer as defined in claim 18 wherein said line powered serial communication device further comprises a Dallas Semiconductor device DS2401.

20. A docking station for mating with a laptop computer comprising:

a Universal Serial Bus (USB) interface having data signal lines and power rails that couple to the laptop computer; and

a docking logic that provides power to said laptop over the power rails of the USB interface.

21. The docking station as defined in claim 20 wherein said docking logic further comprises:

a communication and control logic coupled to said USB power rails adapted to serially communicate over said USB power rails;

a current sense logic adapted to sense current flowing from the docking station; and

a voltage ramp logic adapted to selectively couple power to said USB power rails.

22. The docking station as defined in claim 21 wherein said communication and control logic further comprises a Programmable Array Logic (PAL) configured to operate as a state-machine.

23. The docking station as defined in claim 21 further comprising:

said current sense logic adapted to generate a shut-off signal when current flow from said docking station to said laptop falls below a predefined minimum; and

said communication and control logic coupled to said shut-off signal and adapted to initiate cut-off of power supplied from said docking station responsive to assertion of said shut-off signal.