Power subsystem for a communication network containing a power bus

• US 6,243,818 B1
• Filed: 09/06/2000
• Issued: 06/05/2001
• Est. Priority Date: 05/02/1997
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Sullivan, John M., Schwan, Martin A. K.
• Primary Examiner(s): WILEY, DAVID ARMAND
• Application Number:
  US09/655,955
• Time in Patent Office: 272 Days
• Field of Search: 713/300-340
• US Class Current: 713/300
• 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
• CPC Class Codes: H04L 12/10 Current supply arrangements

Abstract

A method and apparatus of powering components on a network by using a load-share technique and by using over-voltage and current-limiting circuitry. The power subsystem for a component in a network is designed in a load-share manner whereby the power subsystem will supply power to the network bus and to the component load. Under normal operation of the power subsystem, the load will be powered directly from the power subsystem. In the event of a failure, the load will immediately pull power from the bus and thereby maintain network operation. The power subsystem and the power supply are protected from disruptions due to voltage or current surges. Further, the power subsystem is in compliance with the IEEE 1394 specifications in terms of recommended current levels and galvanic isolation of the power sources.

Claims

1. A data processing system comprising in combination:

a single network bus containing data transmission lines and a network power line;

a first power supply unit connected to the network power line;

a a first network load connected to the first power supply;

a second network load connected to the network power line;

a second power supply unit connected to the second network load; and

power selection circuit connected between the second power supply unit and the network power line for selecting the second power supply unit to power the second network load, and for instantaneously selecting the network power line to power the second network load upon removal or failure of power by the second power supply unit.

2. A data processing system as claimed in claim 1, wherein the first network load is also connected to the network power line, and further comprising:

first power supply selection circuit connected between the first power supply unit and the network power line for selecting the first power supply unit to power the first network load.

3. A data processing system as claimed in claim 1, further comprising voltage limiting circuit, connected between the power line and the first network load and the power line and the second network load, for opening the connection to the network power line when the voltage on the network power line exceeds a maximum allowable voltage.

4. A data processing system as claimed in claim 1, further comprising current limiting circuit connected between the first power supply unit and the network power line for opening the connection between the first power supply unit and the network power line when the current on the network power line exceeds a maximum allowable current.

5. A data processing system as claimed in claim 1, wherein the first power selection circuit includes constraining the voltage on the network power line to a predetermined value.

6. A data processing system as claimed in claim 5, wherein the predetermined value is lower than the voltage of the first power supply unit.

7. A power system as claimed in claim 1 further comprising means for steering the current from the power supply unit to the network power line.

8. A power system as claimed in claim 7 wherein the means for steering the current from the power supply unit to the network power line includes a diode.

9. A method of powering components within a data processing system, the data processing system having a single network bus containing data transmission lines and a power bus line, a first component with a first power supply unit and a first network load, a second component with a second power supply unit and a second network load, the power bus line connected to the first power supply and the second network load, said method comprising the steps of:

a supplying power to the power bus line by the first power supply unit;

selecting the second power supply unit, rather than the power bus line, to power the second network load;

removing the power supplied to the second network load by the second power supply unit; and

powering instantaneously the second network load by the network power line after the power from the second power supply unit to the second network load is removed.

10. The method of claim 9, wherein the power bus line is also connected to the first load, and further comprising the step of:

selecting the first power supply unit, rather than the power bus line, to power the first network load.

11. The method of claim 9, further comprising the step of:

opening the connection between the second network load and the network power line in the event of an increase in the network power line current greater than a maximum allowable current.

13. The method of claim 9, further comprising the step of:

opening the connection between the first power supply unit and the network power line when the current on the network power line exceeds a maximum allowable current.

12. The method of comprising the step of:

opening the connection between the first power supply and to the network power line when the voltage on the network power line exceeds a maximum allowable voltage.