from the United States Patent and Trademark Office, Patent
Trial and Appeal Board in No. 95/001, 861, 95/001, 637.
Matthew A. Smith, Smith Baluch LLP, Washington, DC, argued
for Vicor Corporation. Also represented by ANDREW T.
D'Amico, Jr., Vicor Corporation, Andover, MA; Lawrence K.
Kolodney, Fish & Richardson, PC, Boston, MA.
D. Rein, Sidley Austin LLP, Chicago, IL, argued for SynQor,
Inc. Also represented by CONSTANTINE L. Trela, Jr., Bryan C.
LOURIE, TARANTO, and Chen, Circuit Judges.
Inc. (SynQor) owns several patents directed to a particular
architecture for direct current-to-direct current (DC-DC)
power converters, including U.S. Patent Nos. 8, 023, 290 (the
'290 patent) and 7, 272, 021 (the '021 patent)
(hereinafter, we refer to the '290 and '021 patents
collectively as the SynQor Patents). Vicor Corporation
(Vicor) requested, and the Patent and Trademark Office (PTO)
granted, inter partes reexaminations of the SynQor
Patents. The reexaminations were ultimately decided by the
Patent Trial and Appeal Board (Board), which was confronted
with many proposed rejections and highly technical competing
arguments. Vicor appeals the Board's decision in the
'290 patent's reexamination holding that certain
claims are patentable over prior art combinations proposed by
Vicor. SynQor, for its part, appeals the Board's decision
in the '021 patent's reexamination holding that
certain claims in that patent are unpatentable as anticipated
address these two appeals in a single opinion because the two
patents claim very similar inventions, and their respective
reexaminations share common patentability issues. Both
reexaminations were decided by the same panel of
administrative patent judges. The panel's decision in the
'290's reexamination issued on the same date as the
panel's decision on rehearing in the '021's
reexamination. Despite sharing a common panel and having
opinions issued on the same date, the decisions in the
respective reexaminations contain inconsistent findings on
identical issues and on essentially the same record. We
affirm in part, vacate in part, and remand
the Board's decisions in both
DC-DC Power Converters
SynQor Patents claim systems and methods for DC-DC power
conversion. See generally '290 patent col. 17 1.
9-col. 18 1. 35; '021 patent col. 6 1. 21-col. 8 1. 60.
Direct current (DC) flows in only one direction, whereas
alternating current (AC) periodically reverses direction. AC
power supplied from a utility is converted to DC by a
"front end converter." A DC-DC converter receives
the DC output of a front end converter and transforms it into
one or more lower DC voltages.
DC-DC converters at issue in this appeal are designed to
drive logic circuitry in large computer and
telecommunications systems that typically require a number of
different power voltages. The claimed converters perform two
general operations in sequence: "isolation" and
"regulation." Isolation converts a DC input into
AC, reduces the AC voltage using a transformer, and converts
AC back to DC at a voltage level lower than the DC input.
Regulation then restricts that isolated output down to a DC
voltage appropriate for driving logic circuity.
enhances safety and prevents unwanted noise by using a
transformer to lower voltage without using wires connecting
inputs and outputs. A transformer comprises
"primary" and "secondary" windings, such
as coiled wires. The transformer's input is connected to
the primary winding, which transfers electrical energy to the
secondary winding via magnetic fields. The transformer's
output from the secondary winding is a fraction, or multiple,
of the transformer's input determined by the ratio of
turns in the respective primary and secondary windings. For
example, a transformer with a primary winding that has twice
as many turns as the secondary winding will have an output
voltage that is half of its input.
circuitry converts the secondary winding's AC output to
DC using rectifiers. The SynQor Patents' claims all
require use of "controlled" rectifiers, which use
control signals and circuitry to reverse or prevent the flow
of current in one direction. Embodiments of the SynQor
Patents' inventions use a particular type of pre-existing
controlled rectifier known as a "synchronous"
rectifier, which uses a waveform of current flow across one
of the transformer's windings to control switching
circuitry that generates a DC output.
circuitry receives an isolated DC output and regulates it
down to appropriate voltage(s) to drive logic circuitry.
Regulation was known to be implemented using at least two
types of regulators: "switching" regulators and
"linear" regulators. Switching regulators include a
transistor-implemented switch, which turns on and off in
response to one or more parameters sensed in the circuit to
maintain output voltage at a predefined value. Linear
regulators regulate an output by varying the resistance of
Prior Art DC-DC Power Converters
art power architectures for large computer and
telecommunications systems used DC-DC power converters that
integrated isolation and regulation circuitry in each
individual converter. The presence of isolation circuitry in
every converter took up valuable space on circuit boards
where the converters were located, which could have been used
for additional microprocessors, memory, or logic circuitry.
SynQor's Asserted Improvement over the Prior Art
SynQor Patents claim to improve prior art systems by
separating the isolation and regulation functionality of
DC-DC converters into two steps and using a single isolation
stage to drive multiple regulation stages. See
'290 patent Fig. 1, col. 4 U. 40-54; '021 patent Fig.
5, col. 5 11. 6-12. The single isolation stage drives an
"intermediate bus" that is fed to multiple on-board
regulator components. See -2288 J.A.
1117-19. The regulators can be smaller, less
expensive, and more efficient compared to regulators used in
on-board, integrated isolating/regulating converters. SynQor
portrays this separation of isolation and regulation stages
as the key invention of the SynQor Patents and "a
revolutionary new power architecture" developed by
SynQor's CEO-Dr. Martin Schlecht-who is the sole named
inventor on the SynQor Patents. -2288 Open. Br. at 2.
According to SynQor, the new two-stage architecture, which
became known as "Intermediate Bus Architecture"
(IBA), was "hailed in the field, copied by SynQor's
competitors, and widely adopted by the industry."
Disputed Claims of the SynQor Patents
SynQor Patents' claims tailor their coverage of IBAs
general schema by including limitations that require specific
circuit features. First, all of the claims require separate
isolation and regulation stages comprising (1) a
"non-regulating" isolation stage and (2) a
plurality of "non-isolating" regulation stages.
See generally '290 patent col. 17 1. 9-col. 18
1. 35; '021 patent col. 6 1. 21-col. 8 1. 60.
all claims of the '290 patent and claims 49-50 of the
'021 patent require the regulation to be done by
switching regulators. See generally '290 patent
col. 17 1. 9-col. 18 1. 35; -2288 J.A. 115 (reciting claims
49-50 of the '021 patent, added during reexamination).
SynQor argues that switching regulators provide more
efficient regulation than linear regulators used in prior art
for the non-regulating isolation stage, all claims of the
'021 patent require "substantially uninterrupted
flow of power" through a transformer's "primary
and secondary winding circuits." See generally
'021 patent col. 6 1. 21-col. 8 1. 60. The '021
patent's specification describes circuitry that regulates
the flow of power across the primary and secondary windings
by setting a "duty cycle" for periodically
reversing the directional flow of current across the primary
winding. See id. col. 3 1. 62-col. 4 1. 18. The
'021 patent explains that power is always flowing through
the isolation stage, except during "brief switch
transitions." '021 patent col. 4 11. 8-11.
both patents include dependent claims that limit input and
output voltages to ranges appropriate for converters that
receive DC power from a front end converter and output DC
power to drive logic circuitry. See, e.g., '290
patent col. 18 11. 7-9 (claim 7); '021 patent col. 7 11.
40-42 (claim 25). SynQor argues that restricting circuit
operation to these voltage ranges distinguishes prior art
power systems that were not designed for powering
telecommunications or computer systems.
sole independent claim of the '290 patent, claim 1,
covers an IBA converter implemented with switching
A DC-DC power converter system providing plural regulated DC
outputs, each having a regulated voltage, comprising:
a DC input;
a non-regulating isolating converter comprising:
a primary transformer winding circuit having at least one
primary winding that receives power from the DC input; and
a secondary transformer winding circuit having at least one
secondary winding coupled to the at least one primary winding
and having plural controlled rectifiers, each having a
parallel uncontrolled rectifier and each in circuit with a
secondary winding, each controlled rectifier being turned on
and off in synchronization with a voltage waveform of the at
least one primary winding to provide a non-regulated,
isolated DC output; and plural non-isolating switching
regulators, each receiving power from the non-regulated,
isolated DC output of the non-regulating isolating converter
and each providing one of the regulated DC outputs having a
patent col. 1711. 9-30 (emphasis added).
of the '290 patent is exemplary of the dependent claims
in the SynQor Patents that specify input/output voltage
ranges for telecommunications or computer systems:
A power converter system as claimed in claim 1 wherein
each regulated voltage of each of the regulated DC
outputs is of a voltage level to drive logic circuitry.
'290 patent col. 18 11. 7-9 (emphasis added).
of the '021 patent is very similar to claim 1 of the
'290 patent, but includes the "substantially
uninterrupted flow of power" limitation present in all
claims of the'021 patent:
A power converter system comprising:
a normally non-regulating isolation stage ...