Efficient power supply

• US 7,639,520 B1
• Filed: 02/26/2007
• Issued: 12/29/2009
• Est. Priority Date: 02/26/2007
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: Network Appliance Incorporated (NetApp, Inc.)
• Inventors: Zansky, Zoltan, Jacobsen, Bill
• Primary Examiner(s): BERHANE, ADOLF D
• Application Number:
  US11/710,861
• Time in Patent Office: 1,037 Days
• Field of Search: 363/34, 363/37, 363/65, 363/67, 363/71, 363/78, 363/84, 363/89, 363/125, 363/131
• US Class Current: 363/65
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 1/4225 using a non-isolated boost converter
• CPC Class Codes: H02M 7/23 arranged for operation in parallel H02M7/2176 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

The present invention is a method and system for efficiently converting an alternating current (AC) supply to a direct current (DC) output. A power supply in accordance with the present invention may employ variable frequency constant on-time converters whereby switching losses of the converters are approximately proportional with a switching frequency, causing the power supply to be more efficient at light loads. Additionally, a power supply in accordance with the present invention may include multiple-phase converters in which each phase is designed for operation at a fraction of the total maximum load for the power supply.

Claims

1. A power supply, comprising:

an input for receiving an alternating current (AC) supply;

a first converter, said first converter being coupled to said input, said first converter being suitable for converting the AC supply to a direct current (DC) voltage output;

a second converter, said second converter being coupled to said input, said second converter being suitable for converting said AC supply to a direct current (DC) voltage output; and

a converter controller that responds to a load supplied by the power supply and enables at least one of a first converter and second converter based upon an amount of load supplied by the power supply, wherein only said first converter out of said first converter and said second converter is operating when said amount of load is less than a particular load percentage of a maximum load supplied by the power supply, said first converter and said second converter have a switching frequency of a percentage of a maximum switching frequency which corresponds to a load percentage of the maximum load supplied by the power supply.

2. The power supply as claimed in claim 1, wherein said first converter and second converter are operating when said load is greater than the particular load percentage of the maximum load supplied by the power supply.

3. The power supply as claimed in claim 1, further comprising a power factor corrector.

4. The power supply as claimed in claim 3, wherein said power factor corrector includes a boost converter.

5. The power supply as claimed in claim 4, wherein

said boost converter has a switching frequency of a percentage of a maximum switching frequency which corresponds to a load percentage of the maximum load supplied by the power supply.

6. The power supply as claimed in claim 1, wherein said first converter is configured for 0 to 50% of the maximum load.

7. The power supply as claimed in claim 6, wherein said first converter is configured for maximum efficiency at 25% of the maximum load.

8. The power supply as claimed in claim 1, wherein said second converter is configured for 0 to 50% of the maximum load.

9. The power supply as claimed in claim 8, wherein said second converter is configured for maximum efficiency at 25% of the maximum load.

10. A power supply, comprising:

an input for receiving an alternating current (AC) supply;

a first converter, said first converter being coupled to said input, said first converter being suitable for converting the AC supply to a direct current (DC) voltage output;

a second converter, said second converter being coupled to said input, said second converter being suitable for converting said AC supply to a direct current (DC) voltage output;

a third converter, said third converter being coupled to said input, said third converter being suitable for converting said AC supply to a direct current (DC) voltage output; and

a converter controller that responds to a load supplied by the power supply and enables at least one of a first converter, second converter and third converter based upon an amount of load supplied by the power supply, wherein only said first converter out of said first converter, said second converter and said third converter is operating when said amount of load is less than a particular load percentage of a maximum load supplied by the power supply;

said first converter, said second converter and said third converter have a switching frequency of a percentage of a maximum switching frequency which corresponds to a load percentage of the maximum load supplied by the power supply.

11. The power supply as claimed in claim 10, further comprising a power factor corrector.

12. The power supply as claimed in claim 11, wherein said power factor corrector includes a boost converter.

13. The power supply as claimed in claim 12, wherein

said boost converter has a switching frequency of a percentage of a maximum switching frequency which corresponds to a load percentage of the maximum load supplied by the power supply.

14. The power supply as claimed in claim 10, wherein said first converter is configured for 0 to 33% of the maximum load.

15. The power supply as claimed in claim 10, wherein said second converter is configured for 0 to 33% of the maximum load.

16. The power supply as claimed in claim 10, wherein said third converter is configured for 0 to 33% of the maximum load.

17. The power supply as claimed in claim 14, wherein said first converter is configured for maximum efficiency at 17% of the maximum load.

18. The power supply as claimed in claim 15, wherein said second converter is configured for maximum efficiency at 17% of the maximum load.

19. The power supply as claimed in claim 16, wherein said second converter is configured for maximum efficiency at 17% of the maximum load.