Intelligent overcurrent protection for power supplies

• US 7,312,962 B1
• Filed: 12/26/2002
• Issued: 12/25/2007
• Est. Priority Date: 12/26/2002
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Zansky, Zoltan, Jacobsen, Bill, Schmiedeskamp, Bob
• Primary Examiner(s): Sherry, Michael
• Assistant Examiner(s): Nguyen, Danny
• Application Number:
  US10/329,854
• Time in Patent Office: 1,825 Days
• Field of Search: 361/18, 361/79, 361/86, 361/87, 361/91.1, 361/91.2, 361 937- 939, 361/93.1, 361/30, 363/65, 323/283
• US Class Current: 361/30
• CPC Class Codes: H02H 3/087 for dc applications
• CPC Class Codes: H02H 9/02 responsive to excess current current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025

Abstract

The present invention is a method and system for preventing an output of current greater than a desired amount for a redundant power supply system. In an embodiment of the present invention, redundant power supplies may be shut down when the sum of the output currents from the redundant power supplies is greater than a specified maximum current for a single power supply. Additionally, if a power supply should operate outside of desired voltage and current specifications, the power supply may be disabled while the method and system of the present invention monitor the output current of a redundant power supply.

Claims

1. A system for preventing an overcurrent, comprising:

(a) means for determining if each power supply of a plurality of power supplies is operating within a list of specifications;

(b) means for disabling each power supply that is operating outside said list of specifications; and

(c) means for monitoring a total amount of output current of said plurality of power supplies;

wherein one or more of said plurality of power supplies is shut down when said total amount of output current is greater than a desired amount of current, said desired amount of current being less than a maximum current output capable of being supplied by each power supply, wherein said power supplies are shut down by disabling an enable signal coupled to each power supply, the total amount of output current being monitored by summing individual amounts of output current supplied by each power supply through a current sense line coupled to each power supply, wherein upon a first power supply is disabled for operating outside said list of specifications, said total amount of output current from enabled power supplies is still monitored.

2. The system as claimed in claim 1, wherein said list of specifications includes a voltage range.

3. The system as claimed in claim 1, wherein said list of specifications includes a current range.

4. The system as claimed in claim 1, wherein said means for monitoring said total amount of output current sums an output current of each power supply.

5. The system as claimed in claim 4, wherein said output current of each power supply is determined by measuring a signal indicative of said output current.

6. The system as claimed in claim 1, wherein said desired amount of current is adjustable.

7. A power supply system, comprising:

a first input supply;

a first power supply coupled to said first input supply, said first power supply receiving a first input voltage from said first input supply and providing a first output supply;

a second input supply;

a second power supply coupled to said second input supply, said second power supply receiving a second input voltage from said first input supply and providing a second output supply;

a bus coupled to said first power supply and said second power supply;

said bus receiving said first output supply and said second output supply; and

means for monitoring a total amount of output current of said first power supply and said second power supply provided to said bus, wherein one or more of said first power supply and said second power supply is shut down when said total amount of output current on said bus is greater than a desired amount of current, said desired amount of current being less than a maximum current output capable of being supplied by each power supply, said first power supply and said second power supply are shut down by disabling an enable signal coupled to said first power supply and said second power supply, the total amount of output current being monitored by summing individual amounts of output current supplied by said first power supply and said second power supply through a current sense line coupled to each power supply.

8. The power supply system of claim 7, wherein said first input supply and said second input supply provide an unregulated DC voltage.

9. The power supply system of claim 8, wherein said first power supply and said second power supply are DC/DC power supplies which receive an unregulated DC voltage and provide a regulated DC voltage.

10. The system as claimed in claim 7, wherein said desired amount of current is adjustable.

11. A power supply system, comprising:

a first input supply providing a first unregulated DC voltage;

a first power supply coupled to said first input supply, said first power supply receiving said first unregulated DC voltage and providing a first regulated DC voltage;

a second input supply providing a second unregulated DC voltage;

a second power supply coupled to said second input supply, said second power supply receiving said second unregulated DC voltage and providing a second regulated DC voltage;

a bus coupled to said first power supply and said second power supply;

said bus receiving said first regulated DC voltage and said second regulated DC voltage; and

means for monitoring a total amount of output current of said first power supply and said second power supply provided to said bus, wherein one or more of said first power supply and said second power supply is shut down when said total amount of output current on said bus is greater than a desired amount of current, said desired amount of current being less than a maximum current output capable of being supplied by each power supply, said first power supply and said second power supply are shut down by disabling an enable signal coupled to said first power supply and said second power supply, the total amount of output current being monitored by summing individual amounts of output current supplied by said first power supply and said second power supply through a current sense line coupled to each power supply.

12. The system as claimed in claim 11, wherein said desired amount of current is adjustable.