NOTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
PHILIPS LIGHTING NORTH AMERICA CORP.,
PHILIPS LIGHTING HOLDING B.V.,
Appellants
v.
WANGS ALLIANCE CORPORATION, DBA WAC
LIGHTING CO.,
Appellee
______________________
2017-1526
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2015-
01287.
______________________
Decided: April 18, 2018
______________________
ROBERT MANHAS, Wilmer Cutler Pickering Hale and
Dorr LLP, Washington, DC, argued for appellants. Also
represented by ARIANNA EVERS; MARK CHRISTOPHER
FLEMING, CYNTHIA D. VREELAND, Boston, MA.
DAVID C. RADULESCU, Radulescu LLP, New York, NY,
argued for appellee. Also represented by ETAI LAHAV,
MICHAEL D. SADOWITZ, TIGRAN VARDANIAN.
______________________
2 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
Before MOORE, TARANTO, and CHEN, Circuit Judges.
TARANTO, Circuit Judge.
Philips Lighting North America Corp. owns U.S. Pa-
tent No. 6,013,988. In an inter partes review, the Patent
Trial & Appeal Board decided that claims 1 and 2 of the
patent are unpatentable. We affirm.
I
A
The ’988 patent describes a circuit arrangement for a
signaling light, such as a traffic light, that uses a light-
emitting diode (LED), rather than a traditional incandes-
cent lamp, as its light source. ’988 patent, col. 1, lines 21–
31. Typically, a signaling light in a traffic light system is
regulated by a control unit having a solid-state relay—an
electronic switch that turns on and off the power supplied
to the light. Id., col. 1, lines 32–34; see also id., col. 3,
lines 21–25. The control unit conducts status tests of the
relay and of the signaling light at the connection termi-
nals to make sure that multiple traffic lights (e.g., red and
green) are not on at the same time. See id., col. 1, lines
32–41.
Although replacing traditional incandescent traffic
lights with LEDs saves energy, a simple replacement
causes problems for the status tests. Id., col. 1, lines 38–
41. The problem derives from the fact that solid-state
relays conduct current even in the “off” state, resulting in
“leakage current.” Id., col. 1, line 36–38. “Leakage cur-
rent” is not a problem for an incandescent lamp, which
has “a comparatively low impedance . . . in the extin-
guished state, with the result that the removal of the
leakage current through the incandescent lamp leads to
only a low voltage at the connection terminals of the
control circuit.” Id., col. 1, lines 61–65. But leakage
current is a problem for LEDs, which are semiconductor
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 3
light sources having a high impedance even in the “off”
state; for LEDs, leakage current from a solid-state relay
results in a relatively high voltage at the connection
terminals and produces incorrect status test results. Id.,
col. 1, lines 36–41.
The solution described in the ’988 patent is the addi-
tion of a subsidiary circuit called a “self-regulating cur-
rent-conducting network,” which allows for the
retrofitting of LEDs in existing traffic light systems
without producing status-test problems. Id., col. 1, lines
47–59. An LED traffic light system is depicted in Figure
1 of the patent (Philips-annotated version below), where
VB is the control unit; LB is the LED; A and B are the
connection terminals to the control unit; and C and D are
the connection terminals to the LED. Id., col. 2, lines 55–
60, & Fig. 1.
This case has focused on the three numbered compo-
nents (I, II, and III) and the order in which they appear:
specifically, I before II before III. The input filter (I)
selectively rejects and transmits input signals at particu-
lar frequencies and contains a rectifier that transforms
alternating current (AC) from the power lines to direct
current (DC) that flows to the LED. Id., col. 2, lines 22–
24, 57; id., col. 4, lines 2–5; see also Wangs Alliance Corp.
v. Koninklijke Philips N.V., No. IPR2015-01287, 2015 WL
9599171, at *4 (P.T.A.B. Nov. 30, 2015) (Institution Deci-
sion). The converter (III) contains a control circuit and a
switch-mode converter (“switching element”) that oper-
4 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
ates the LED. ’988 patent, col. 2, lines 15–22, 57–58; id.,
col. 4, lines 24–60 & Fig. 4 (control circuit = SC). Between
the filter and converter, i.e., after filter I and before
converter III, a “self-regulating current-conducting net-
work” (II) drains off the leakage current from the control
unit VB when the control unit is in the “off” state, result-
ing in a low voltage at the connection terminals and
therefore producing correct status test results. Id., col. 1,
lines 47–55; id., col. 2, lines 59–60.
That configuration is described in independent
claim 1 of the patent, which reads:
1. A circuit arrangement for operating a semi-
conductor light source, said circuit arrangement
comprising:
connection terminals for connecting the circuit
arrangement to outputs from a control unit for
controlling the semiconductor light source;
input filter means coupled to the connection
terminals;
a converter comprising a control circuit, said
converter being coupled to output means of the
input filter means; and
output terminals for coupled to output means
of said converter for connecting said circuit ar-
rangement to the semiconductor light source,
characterized in that said converter comprises
a switched-mode power supply for providing pow-
er to said semiconductor light source, said
switched-mode power supply having a switching
element which is cyclically switched on and off by
said control circuit, and the circuit arrangement
further comprises a self-regulating current-
conducting network coupled between said fil-
ter means and said converter, said self-
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 5
regulating current-conducting network draining
off a leakage current in the control unit when said
control unit is in a non-conducting state.
Id., col. 5, lines 9–32 (emphasis added).
Dependent claim 2 covers a preferred embodiment, in
which the circuit arrangement includes a means for
deactivating the current-conducting network when the
control unit is in the “on” state so that there is no power
dissipation through the current-conducting network. Id.,
col. 1, line 66 through col. 2, line 3. Claim 2 reads: “The
circuit arrangement as claimed in claim 1, characterized
in that the circuit arrangement comprises means [f]or
deactivating the self-regulating current-conducting net-
work [w]hen the converter is switched on.” Id., col. 5,
lines 33–36. The deactivating means in that preferred
embodiment may be separate from the other components
in Figure 1 or may, in a further preferred embodiment,
form part of the control circuit of the converter III. Id.,
col. 3, lines 33–60 & Figs. 2–3.
B
Wangs Alliance Corporation filed a petition for an in-
ter partes review of the ’988 patent under 35 U.S.C.
§§ 311–19. The Board instituted a review of claims 1
and 2 as likely unpatentable for obviousness under 35
U.S.C. § 103 based on the combination of U.S. Patent
No. 5,661,645 (Hochstein) and U.S. Patent No. 5,075,601
(Hildebrand). Institution Decision, 2015 WL 9599171, at
*9. The Board issued a final written decision on Novem-
ber 23, 2016, concluding that both claims 1 and 2 are
unpatentable for obviousness based on the Hochstein/
Hildebrand combination. J.A. 1–55 (Final Written Deci-
sion, Wangs Alliance Corp. v. Koninklijke Philips N.V.,
No. IPR2015-01287 (P.T.A.B. Nov. 23, 2016), Paper No. 60
(Board Decision)).
6 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
Philips timely appealed that decision. We have juris-
diction under 28 U.S.C. § 1295(a)(4)(A).
II
Philips challenges, for lack of substantial evidence
support, the Board’s factual findings that a skilled artisan
would have been motivated to combine Hochstein and
Hildebrand and had a reasonable expectation of success
based on that combination. See Novartis AG v. Torrent
Pharms. Ltd., 853 F.3d 1316, 1324 (Fed. Cir. 2017). We
reject both challenges.
A
Substantial evidence supports the Board’s determina-
tion that a person of ordinary skill in the art would have
been motivated to combine Hochstein and Hildebrand.
Hochstein specifically addresses the leakage current
problem caused by using LEDs in traditional traffic signal
lights, and it proposes a solution that drains leakage
current without causing inefficient use of electric power
(poor power factor). Hochstein, col. 5, lines 11–26; id., col.
6, lines 31–62. Hochstein’s Figure 5, reproduced in the
Board’s decision with annotations by Philips, shows the
(now undisputed) correspondence to the ’988 patent
elements at issue:
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 7
Board Decision at 27.
As seen in the figure, an optional adaptive clamp cir-
cuit, corresponding to the “current-conducting network” in
the ’988 patent, is placed across the input terminals of the
power lines. Hochstein, col. 7, lines 17–19. The location
of the adaptive clamp circuit between the control unit and
the LEDs allows the adaptive clamp circuit to monitor the
line voltage and switch itself in or out of the circuit as
necessary. Id., col. 7, lines 39–50. Meanwhile, the input
filter component “keeps conducted interference from
feeding back into the power lines where it might cause
problems to other circuitry on the line.” Id., col. 5, lines
33–35. In the configuration in Hochstein, the adaptive
clamp circuit is before the filter, not “between” the filter
and the converter, as required by claim 1 of the ’988
patent. ’988 patent, col. 5, lines 27–29. 1 Hochstein gives
no reason for placing the adaptive clamp circuit before,
instead of after, the filter. See Board Decision at 44.
Hildebrand shows a traffic light system with an order
of pertinent components that matches the order in the
’988 patent, though not in the LED context. Like
Hochstein and the ’988 patent, Hildebrand recognizes the
leakage current and status test problem; but Hildebrand
discusses that problem in the context of replacing tradi-
tional incandescent lamps with neon or fluorescent traffic
lights, not LEDs. Hildebrand, col. 1, lines 11–33. Hilde-
brand proposes using a “dynamic load” circuit (corre-
sponding to the ’988 patent’s “current-conducting
network”) to drain the excess current at low voltages. Id.,
col. 1, lines 34–41. Hildebrand places the “dynamic load”
circuit after the input filter, i.e., as in the ’988 patent,
“between” the filter and the converter. Board Decision
1 We focus on claim 1, as Philips makes no separate
arguments on appeal as to dependent claim 2.
8 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
at 31; see Hildebrand, col. 5, line 57 through col. 6, line 6
& Fig. 1A.
On appeal, Philips does not dispute the Board’s find-
ing that the invention in claim 1 of the ’988 patent is
disclosed by the combination of Hochstein and Hilde-
brand—i.e., by using Hochstein’s group of components,
including an LED, but with Hildebrand’s sequencing
(current-conducting network after the input filter).
Philips argues, however, that the Board improperly failed
to identify an “affirmative reason” to combine Hochstein
and Hildebrand and instead relied solely on the notion
that choosing the order of components was a matter of
“design choice.” Philips’s Br. 23. We disagree with
Philips’s reading of the Board decision, and we conclude
that the Board’s rationale for the combination was suffi-
cient under KSR International Co. v. Teleflex Inc., 550
U.S. 398 (2007).
The Board did not rely on a broad notion of “design
choice” as sufficient to find that a skilled artisan would
have combined the references; to the contrary, it refused
to adopt a “mere[] asserti[on]” of “design choice” and
insisted on reviewing the context-specific evidence for the
soundness of that rationale in the particular circumstanc-
es of this review. Board Decision at 36. The Board first
found that both references address the same problem (i.e.,
leakage current in traffic signal systems employing a light
source different from traditional incandescent lamps) and
propose similar solutions (i.e., similar circuitry—adaptive
clamp circuit in Hochstein, and dynamic load circuit in
Hildebrand). Id. at 32–35. Both “references are thus
substantially pertinent to solving precisely the same
problem addressed by the ’988 patent and show the
demand for designs that solve the known problem,” in-
cluding the two in Hochstein and Hildebrand. Id. at 33.
The Board also made a specific finding that changing
the order of the filter and adaptive clamp circuit (current-
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 9
conducting network analogue) in Hochstein was an obvi-
ous matter of design choice because the two designs were
known in the art, recognized as solutions to the particular
problem, and functionally equivalent. Id. at 36–45. The
Board determined that a person of skill in the art would
look to both Hochstein and Hildebrand to solve the leak-
age current problem and that those two references “dis-
close the two possible locations for the circuitry that
drains the leakage current: either before an input filter
or after an input filter.” Id. at 38. The Board further
found that Hochstein nowhere teaches that the filter’s
function includes protection of the adaptive clamp circuit
from converter-generated noise or precludes placement of
the filter before the adaptive clamp circuit (the location in
Hildebrand and the ’988 patent). Id. at 43–44.
For further support, the Board pointed to an excerpt
from the textbook Fundamentals of Power Electronics,
which states that “[i]t is nearly always required that a
filter be added at the power input of a switching convert-
er.” Id. at 43 (quoting Robert W. Erickson, Fundamentals
of Power Electronics 377 (2d ed. 2001)). 2 Based on that
excerpt, the Board found that a person of ordinary skill
would understand not only the operation of that filter but
also that the “fundamental placement” of the filter is at
the power input. Id. at 44.
Based on the teachings of Hildebrand and Hochstein
and the testimony of Wangs’s expert Mr. Robert Tingler,
with support from Fundamentals of Power, the Board
found that a person of skill, reading Hochstein, would
know that the input filter may be placed at the power
2 Philips argues in its reply brief in this court that
the Board was not entitled to rely on this particular
excerpt from Fundamentals of Power. Philips’s Reply
Br. 18–22. But Philips did not so argue in its principal
brief. We therefore do not consider the argument.
10 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
input before the adaptive clamp circuit, as shown in
Fig. 1A in Hildebrand and in Figure 1 of the ’988 patent.
Id. at 41–45; see also id. at 37 (“The various differences
between Hochstein and Hildebrand have not been shown
to be of particular relevance to selecting whether to place
the adaptive clamp circuit after the [input] filter.”).
The Board considered, but rejected, Philips’s argu-
ment that a skilled artisan would not place Hochstein’s
input filter before the adaptive clamp circuit because that
modified configuration would expose the adaptive clamp
circuit to malfunctioning noise from the converter. See id.
at 43 (noting that Philips’s expert Dr. Regan Zane testi-
fied in his deposition that a skilled artisan would not
know how to address any noise issues and speculated that
such noise “could cause undesirable behavior,” but not
testifying as to what level of noise would be generated by
the converter or its result) (quoting J.A. 1246–47). The
Board was persuaded by the record evidence, including
the testimony of Wangs’s expert Mr. Tingler, that, even if
the adaptive clamp would be exposed to noise from the
converter, the noise from the converter would not be a
“malfunctioning” noise that would counsel against the
adoption of a filter-first configuration by a relevant skilled
artisan, who would be able to identify and mitigate any
noise. Id. at 42–43. 3 The Board ultimately found “that it
is highly unlikely that [the] adaptive clamp circuit would
be affected by noise, and thus malfunction.” Id. at 45.
Philips complains that the Board did not identify the
specific “affirmative reason” for a person of skill looking at
Hochstein to adopt the alternative configuration in Hilde-
brand. But in the circumstances of this case, we conclude,
Philips is demanding too much. Under KSR, we see no
need for more than what the Board found in this case,
3 In section II.B infra, we discuss this expert dis-
pute about noise malfunction further.
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 11
including that (1) there were just two obvious design
choices in the respect put at issue (Hochstein and Hilde-
brand), which solve the same problem in the same way
but with the filter and current-conducting network
swapped in their locations, (2) the two references “show
the demand for designs that solve the known problem,” id.
at 33; (3) Hildebrand’s location choice was a common and
approved design that could be used in Hochstein; and
(4) Hochstein would not malfunction if modified to use
such a design. These findings suffice to establish a reason
for a skilled artisan, seeking to solve the status-test
problem, to use a three-component circuit arrangement as
found in both references and to choose either of the two
disclosed orders of the first two components within that
arrangement—specifically, the order that is especially
common in the art and that is used in the ’988 patent.
See KSR, 550 U.S. at 416 (combining “familiar elements
according to known methods is likely to be obvious when
it does no more than yield predictable results”).
For those reasons, we conclude that substantial
evidence supports the Board’s finding of a motivation to
combine. 4
B
Philips challenges the Board’s finding that a person of
ordinary skill in the art would have had a reasonable
expectation of success in changing the order of the filter
and adaptive clamp in Hochstein. Philips contends that,
unless the filter remained between Hochstein’s adaptive
4 Because we do not rely on the Board’s additional
reasoning in a footnote of its decision that changing the
order of Hochstein’s filter and adaptive clamp would
provide an additional benefit, Board Decision at 44 n.12,
we need not address Philips’s contention that Philips
lacked adequate notice of that reasoning.
12 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
clamp and buck/boost converter, the converter would
introduce noise that would cause the clamp to malfunc-
tion. The Board found that the relevant skilled artisan
would have had a reasonable expectation of success
because (1) the filter’s original placement in Hochstein
does not indicate a need to protect the adaptive clamp
from noise; (2) any noise from the converter in the
swapped configuration can be addressed by a person of
skill; and (3) at the time when the adaptive clamp is most
susceptible to malfunction, noise from the converter is at
its lowest or nonexistent. Board Decision at 48 (referring
to id. at 41–45). We conclude that the Board’s finding is
supported by substantial evidence.
First, Philips repeatedly characterizes Hochstein as
teaching that its filter was intended to protect the adap-
tive clamp in addition to the AC grid, therefore preventing
the proposed swap. But Hochstein does not say that, at
least not clearly. Hochstein describes the filter as neces-
sary to prevent “conducted interference from feeding back
into the power lines where it might cause problems to
other circuitry on the lines,” Hochstein, col. 5, lines 33–35,
and states that “conducted interference is a concern
because of the interference potential with other services
(radio communications for example),” id., col. 2, lines 60–
63. Both parties’ experts agreed on that point. And the
Board found that Hochstein nowhere indicates that the
filter must be placed between the converter and adaptive
clamp to prevent noise from interfering with the function-
ing of the clamp. Board Decision at 44, 48.
Second, Philips argues that Mr. Tingler’s testimony
(for Wangs) is not sufficient to support the Board’s finding
that a person of skill could identify and mitigate any
potential malfunction from any increased clamp exposure
to converter-created noise caused by moving the filter to
the pre-clamp position. We disagree. In response to Dr.
Zane’s testimony (for Philips) about possible malfunction,
Mr. Tingler pointed out that Hochstein does not indicate a
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 13
concern for protecting the adaptive clamp circuit from
noise. J.A. 1062. 5 Even if it were a concern, Mr. Tingler
added, a skilled artisan would build a prototype circuit in
order to assess how the circuit functioned, including how
much, if any, noise from the converter interfered with the
adaptive clamp, and the skilled artisan could add “a tiny
amount of filtering capacitance” between the converter
and adaptive clamp if needed. J.A. 2948. On the record
developed in the proceeding, the Board could properly
credit Mr. Tingler’s explanation.
It may be that Mr. Tingler was not very specific in his
response to Dr. Zane’s malfunction theory—but neither
was Dr. Zane very specific in explaining his theory. Dr.
Zane’s theory was “that a person of ordinary skill in the
art would not recognize what would be required to have a
circuit that works properly in moving the adaptive clamp
circuit from Hochstein to other locations.” Board Decision
at 43. He observed that “[t]he adaptive clamp circuit [in
Hochstein] would be largely protected from that [electro-
magnetic interference noise] sitting in its location on the
AC line.” J.A. 1245. If moved to the Hildebrand location,
Dr. Zane stated, the clamp “would be susceptible to any
noise that feeds into that circuit, noise that could come
from the power converter,” and such “noise on the line
generated from the power converter could cause undesir-
able behavior of the circuit.” J.A. 1245–46. Dr. Zane did
5 As Wangs points out, the ’988 patent does not re-
quire a particular type of converter or explain how noise
from any particular converter must be filtered in light of
the location of the current-conducting network. See
Wangs’s Br. 20 n.1 (citing ’988 patent, col. 2, lines 15–19).
Although the current-conducting network in the ’988
patent has some internal filtering capacity, the disclosure
does not indicate that such filtering is necessary for
effective operation of the current-conducting network.
14 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
not identify how much noise is likely to be introduced by
Hochstein’s buck/boost converter. Nevertheless, he con-
tended that, if the noise occurs when the voltage level is
near the threshold below which the adaptive clamp turns
on to drain current, it could cause the adaptive clamp to
turn on and off. See J.A. 1247–48 (adaptive clamp
“changes its behavior” at particular “points . . . according
to whatever the design is of that adaptive clamp circuit,”
which “are the thresholds in the operation”); J.A. 1249
(“My opinion is that the noise that would be generated on
the line could cause undesirable behavior of the circuit
including, but not limited to, the turn on and off at these
threshold points.”). Without any identification by Dr.
Zane of a specific noise-level problem, the Board did not
have to require Mr. Tingler to identify a solution more
specific than he described.
Finally, Philips attacks the Board’s third finding, i.e.,
that converter noise is at its lowest when the adaptive
clamp is most susceptible to malfunction, as “unsupported
and manifestly erroneous.” Philips’s Br. 37. But the
Board’s finding of a reasonable expectation of success
logically can stand on the Board’s first two findings,
including the finding that a relevant skilled artisan could
identify and mitigate any potential malfunction from
relocating the filter; and Philips has not shown otherwise.
In any event, this third finding was neither unsupported
nor manifestly erroneous.
As Philips recognizes, Philips’s Br. 39 n.5, the Board’s
finding was based on Mr. Tingler’s explanation that the
adaptive clamp actively clamps (drains leakage current)
only when the buck/boost converter is off and not generat-
ing noise. See Board Decision at 44 (citing J.A. 1063–64).
Mr. Tingler reasoned that “because the adaptive clamp is
not operating when the converter is on, and because the
converter is the source of the [electromagnetic interfer-
ence] noise, it is highly unlikely that the adaptive clamp
circuit could be affected by such noise.” J.A. 1064. Based
PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP. 15
on that testimony, the Board “deduce[d] that, when the
converter is off, any noise from the converter is at its
lowest or absent when the adaptive clamp circuit is sup-
posed to sense the threshold voltage in order to drain the
current.” Board Decision at 44.
In making that finding, the Board properly focused on
the source of the potential “malfunction” suggested by
Philips’s expert—noise generated when the voltage is at a
level near the clamp’s on/off threshold for its draining
operation (e.g., 40 volts, see Hochstein, col. 6, lines 42–45;
id., col. 7, lines 53–57), causing the clamp mistakenly to
switch to or from the draining position. See J.A. 1245–49
(Zane deposition testimony). And the Board had a suffi-
cient basis, in Mr. Tingler’s testimony and Hochstein, to
find that such a mistake is unlikely to occur when the
converter is making noise of any significance. The Board
could find that such noise occurs only when the converter
is on. When the converter is on, however, although there
may be noise, it is highly unlikely to matter for the
clamp’s on/off decision. That is because the clamp bases
that decision on voltage being below an on/off threshold
that is far lower than the voltage present when the con-
verter is on. See Hochstein, col. 6, lines 36–45 (“The
adaptive clamp circuit monitors the input voltage feeding
the LED array” and “assumes that voltages lower than a
certain value (typically 40 volts) are due to leakage cur-
rents through the solid state control relay or switch.”); id.,
col. 7, line 63 to col. 8, line 1 (voltage of 120V applied
when light turns on); J.A. 1064 (120V applied when light,
hence converter, is on). On the evidence, it is reasonable
to find that any noise from the converter is unlikely to
cause the clamp to somehow sense, at the already high
level of voltage, a much lower level of voltage at which the
clamp makes its on/off decision.
For those reasons, we see no reversible error in the
Board’s determination that a person of skill would have
16 PHILIPS LIGHTING NORTH AMERICA v. WANGS ALLIANCE CORP.
had a reasonable expectation of success based on the
proposed combination.
III
We affirm the Board’s ruling that claims 1 and 2 of
the ’988 patent are unpatentable.
Each party shall bear its own costs.
AFFIRMED