Powering a notebook across a USB interface

• US 6,668,296 B1
• Filed: 06/30/2000
• Issued: 12/23/2003
• Est. Priority Date: 06/30/2000
• Status: Expired due to Term

• 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.
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): CHUNG TRANS, XUONG MY
• Application Number:
  US09/608,082
• Time in Patent Office: 1,271 Days
• Field of Search: 710/303, 710/304, 710/300, 710/301, 710/302, 710/305, 710/306, 710/313, 713/320, 713/322, 713/323, 713/324, 713/330, 713/340
• 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 device comprising a docking station;

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

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

said laptop computer comprising;

a bridge device, said bridge device adapted to communicate over said communication bus being a Universal Serial Bus (USB) interface; and

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.

2. The computer system as defined in claim 1 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.

3. The computer system as defined in claim 2 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.

4. The computer system as defined in claim 2 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

a 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.

5. The computer system as defined in claim 4 wherein said line powered serial communication device further comprises a Dallas Semiconductor device DS2401.

6. The computer system as defined in claim 1 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.

7. The computer system as defined in claim 6 wherein said communication and control logic further comprises a Programmable Array Logic (PAL) configured to operate as a state-machine.

8. The computer system as defined in claim 6 further comprising:

said current sense logic adapted to generate a shutoff 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 shutoff signal.

9. 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:

coupling the laptop computer, while in operation, 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;

providing power on said power lines of said communication bus by said docking station; and

thereby

powering said laptop computer from said docking station across said communication bus.

10. The method as defined in claim 9 wherein said communication bus is a Universal Serial Bus.

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

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

powering said laptop computer from said docking station across said communication bus.

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

13. 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.

14. The laptop computer as defined in claim 13 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.

15. The laptop computer as defined in claim 14 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.

16. The laptop computer as defined in claim 14 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.

17. The laptop computer as defined in claim 16 wherein said line powered serial communication device further comprises a Dallas Semiconductor device DS2401.

18. 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, 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.

19. The docking station as defined in claim 18 wherein said communication and control logic further comprises a Programmable Array Logic (PAL) configured to operate as a state-machine.

20. The docking station as defined in claim 18 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.

21. A system comprising:

a laptop computer comprising;

a data bus having power lines;

a voltage control circuit coupled to power lines of the data bus, wherein the voltage control circuit selectively couples power to the power lines; and

wherein the laptop computer is adapted to draw operational power from the data bus power lines, and wherein the voltage control unit is adapted to refrain from powering the power lines when the laptop draws operational power from the data bus.

22. The laptop computer as defined in claim 21 further comprising:

a signaling circuit coupled to the power lines of the data bus, wherein the signaling circuit is adapted to serially communicate over the power lines of the data bus; and

wherein the laptop computer communicates an ability to draw operational power from the data bus by the signaling circuit communicating over the power lines of the data bus.

23. A computer system, comprising:

a device having power available therein;

a laptop computer coupled to said device by way of a communication bus operated under a communication protocol that allows for powering of an external device across communication bus power lines by the laptop computer;

said laptop computer powered by said device across the power lines of said communication bus;

a voltage control unit coupled to power rails of the communication bus, the voltage control unit adapted to selectively provide power to the communication bus power lines; and

a signaling circuit coupled to the communication bus power lines, the signaling circuit adapted to respond to communication signals on the communication bus to identify the laptop as capable of receiving power on the communication bus power lines.

24. The computer system as defined in claim 23 wherein the signaling circuit further comprises a line powered serial communication device coupled across the communication bus power lines, the line powered communication device responds to communication signals on the communication bus power lines to identify the laptop as capable of receiving power across the communication bus power lines.

25. The computer system as defined in claim 24 wherein the signaling circuit further comprises a coupling current logic coupled across the communication bus power lines, the coupling current logic drawing an electrical current from the power lines when a voltage across the power lines exceeds a threshold voltage.