Electric power conversion systems – Current conversion – Having plural converters for single conversion
Reexamination Certificate
2001-10-31
2003-11-18
Patel, Rajnikant B. (Department: 2838)
Electric power conversion systems
Current conversion
Having plural converters for single conversion
C363S124000, C323S282000
Reexamination Certificate
active
06650556
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates generally to DC—DC converters and voltage regulators, and more specifically to a multi-phase DC—DC converter having redundant DC—DC phases or modules isolated by short protection mechanisms.
2. Background Art
FIG. 1A
shows a simplified example of an electronic system
5
according to the prior art. The system is powered by an AC source
6
, to which is connected an AC-DC converter
7
. One component of a DC-powered electronic system which is known to be subject to various types of failures, is the DC—DC converter
8
, whose primary function is typically to step the DC voltage down from e.g. 12 volts provided by the AC-DC converter to 5 volts or 3.3 volts or whatever is required by the particular load
9
for which the system is designed. Therefore, in previous systems it has been known to provide a redundant or duplicate DC—DC converter
10
in parallel with the primary DC—DC converter
7
. This is commonly known as “N+1 redundancy”. Unfortunately, this seldom-used protection has meant doubling the cost of the DC—DC converter portion of the system.
FIG. 1B
shows an exemplary DC—DC converter
8
(or
10
), such as may be used in the system of FIG.
1
A. The DC—DC converter
8
includes a duty cycle controller
11
which provides duty cycle control signals SG
2
and SG
3
to respective switches Q
2
(“top switch”) and Q
3
(“bottom switch”) of a synchronous multi-phase buck regulator
12
. The top switch Q
2
is often called a pass switching element, and the bottom switch Q
3
is often called a synchronous switching element. The output of the regulator
12
is taken from the switch node between the two switches, and is fed to an inductor L
1
which stores energy and feeds into a diode DO which prevents current from returning into the regulator from the load. The inductor L
1
and capacitor C
1
smooth the provided voltage and amperage over time. A capacitor C
2
is coupled across the load to assist the regulator by providing current in response to changing demands from the load.
James Dinh is co-inventor of the present invention and is the inventor of a related invention disclosed in U.S. Pat. No. 6,262,566 “DC-to-DC Controller Having a Multi-Phase Synchronous Buck Regulator” which issued Jul. 17, 2001. Both this patent and that one are assigned to Intel Corporation.
FIG. 2
shows a simplified, exemplary electronic system according to the '566 patent. In that system, the DC—DC converter is split into multiple phases 1-M (elements
21
to
24
), which are controlled by a multi-phase controller
26
. In general, the phases 1-M are out of phase with each other. Each DC—DC phase contributes to the overall output current provided to the load. The multi-phase controller sequences the phases to reduce ripple at the input and the output.
In the system of
FIG. 1A
, if the main DC—DC unit
8
fails, the N+1 redundant DC—DC unit
10
is there to continue powering the load. In the system of
FIG. 2
, if any of the DC—DC phases fails, either the load will be underpowered, or the remaining DC—DC phases will have to work harder to make up for the lost DC—DC phase(s). This may lead to premature failure of the overall DC—DC system, as the surviving DC—DC phases may have to work beyond their design parameters. In some cases, loss of one or more DC—DC phases may even result in a domino effect that takes down the other DC—DC phases, resulting in a loss of power to the load, or perhaps even destruction of the load.
If one were willing to bear the cost of doubling-up the DC—DC componentry, one could impose the
FIG. 1A
N+1 thinking on the
FIG. 2
system, and have two complete sets of DC—DC converter
20
in an N+1 redundant system.
The present invention, however, offers a more insightful, efficient, and inexpensive solution.
REFERENCES:
patent: 5270589 (1993-12-01), Sawada et al.
patent: 5592072 (1997-01-01), Brown
patent: 5870296 (1999-02-01), Schaffer
patent: 5892389 (1999-04-01), Lai
patent: 6031702 (2000-02-01), Williams
patent: 6031743 (2000-02-01), Carpenter et al.
patent: 6035261 (2000-03-01), Carpenter et al.
patent: 6055167 (2000-04-01), Shamkovich et al.
patent: 6362608 (2002-03-01), Ashburn et al.
patent: 6404175 (2002-06-01), Yang et al.
Budelman Gerald A.
Dinh James S.
Patel Rajnikant B.
Trop Pruner & Hu P.C.
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