Fairchild Semiconductor Corporation et al v. Power Integrations Inc.

Filing 338

MEMORANDUM OPINION re #193 & #196 motions for summary judgment. Signed by Judge Leonard P. Stark on 5/4/15. (ntl)

IN THE UNITED STATES DISTRICT COURT
FOR THE DISTRICT OF DELAWARE
FAIRCHILD SEMICONDUCTOR
CORPORATION and FAIRCHILD
(TAIWAN) CORPORATION,
Plaintiffs,
C.A. No. 12-540-LPS

v.
POWER INTEGRATIONS, INC.,
Defendant.

John G. Day, Lauren E. Maguire, Andrew C. Mayo, ASHBY & GEDDES, Wilmington, DE
Blair M. Jacobs, Christina A. Ondrick, PAUL HASTIN GS LLP, Washington, DC
Leigh J. Martinson, MCDERMOTT, WILL & EMERY LLP, Boston, MA
Patrick James Stafford, MCDERMOTT, WILL & EMERY LLP, Washington, DC
Attorneys for Plaintiffs.

William J. Marsden, Jr., Joseph B. Warden, Jr., FISH & RICHARDSON P.C., Wilmington, DE
Frank E. Scherkenbach, FISH & RICHARDSON P .C., Boston, MA
Howard G. Pollack, Michael R. Headley, Neil Warren, FISH & RICHARDSON P.C., Redwood
City, CA
Attorneys for Defendant.

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MEMORANDUM OPINION

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May4, 2015
Wilmington, Delaware

Pending before the Court are the following motions:
1.

Fairchild's Motion for Summary Judgment (D.1. 193); and

2.

Power Integrations' Motion for Summary Judgment (D.I. 196).

Prior opinions addressed aspects of these motions. (See D.I. 295, 329) Here the Court

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resolves the remaining issues raised by both motions. 1

I.

BACKGROUND
On May 1, 2012, Plaintiffs Fairchild Semiconductor Corporation and Fairchild (Taiwan)

Corporation (collectively, "Fairchild" or "Plaintiffs") filed a complaint against Power
Integrations, Inc. ("PI" or "Defendant") alleging infringement of U.S. Patent Nos. 7,525,259
("the '259 Patent"), 7,259,972 ("the '972 Patent"), 7,616,461 ("the '461 Patent"), and 7,286,123
(''the '123 Patent"). (D.I. 1) On June 21, 2012, Power Integrations counterclaimed against
Fairchild, alleging infringement of U.S. Patent Nos. 6,229,366 (''the '366 Patent"), 7,876,587
("the '587 Patent"), 8,115,457 ("the '457 Patent"), and 7,995,359 ("the '359 Patent").
Fact and expert discovery are complete, and a trial will begin on May 26, 2015. The
Court heard oral argument on the pending motions on March 3, 2015. (D.I. 292, or "Tr.")

II.

LEGAL STANDARDS
Pursuant to Rule 56(a) of the Federal Rules of Civil Procedure, "[t]he court shall grant

summary judgment if the movant shows that there is no genuine dispute as to any material fact
and the movant is entitled to judgment as a matter of law." The moving party bears the burden of
a genuine issue of material fact. See Matsushita Elec. Indus. Co., Ltd. v. Zenith Radio Corp., 475

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Depending on how one counts, the parties filed approximately 23 pretrial motions.
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U.S. 574, 585-86 (1986). An assertion that a fact cannot be - or, alternatively, is - genuinely
disputed demonstrating the absence of must be supported either by citing to "particular parts of
materials in the record, including depositions, documents, electronically stored information,
affidavits or declarations, stipulations (including those made for purposes of the motion only),
admissions, interrogatory answers, or other materials," or by "showing that the materials cited do
not establish the absence or presence of a genuine dispute, or that an adverse party cannot
produce admissible evidence to support the fact." Fed. R. Civ. P. 56(c)(l)(A) & (B). If the
moving party has carried its burden, the nonmovant must then "come forward with specific facts
showing that there is a genuine issue for trial." Matsushita, 475 U.S. at 587 (internal quotation
marks omitted). The Court will "draw all reasonable inferences in favor of the nonmoving party,
and it may not make credibility determinations or weigh the evidence." Reeves v. Sanderson

Plumbing Prods., Inc., 530 U.S. 133, 150 (2000).
To defeat a motion for summary judgment, the nonmoving party must "do more than
simply show that there is some metaphysical doubt as to the material facts." Matsushita, 475
U.S. at 586; see also Podobnikv. U.S. Postal Serv., 409 F.3d 584, 594 (3d Cir. 2005) (stating
party opposing summary judgment "must present more than just bare assertions, conclusory
allegations or suspicions to show the existence of a genuine issue") (internal quotation marks
omitted). However, the "mere existence of some alleged factual dispute between the parties will

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not defeat an otherwise properly supported motion for summary judgment;" a factual dispute is

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genuine only where ''the evidence is such that a reasonable jury could return a verdict for the

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nonmoving party." Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 247-48 (1986). "If the

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evidence is merely colorable, or is not significantly probative, summary judgment may be

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granted." Id. at 249-50 (internal citations omitted); see also Celotex Corp. v. Catrett, 477 U.S.
317, 322 (1986) (stating entry of summary judgment is mandated "against a party who fails to
make a showing sufficient to establish the existence of an element essential to that party's case,
and on which that party will bear the burden of proof at trial"). Thus, the "mere existence of a
scintilla of evidence" in support of the nonmoving party's position is insufficient to defeat a
motion for summary judgment; there must be "evidence on which the jury could reasonably find"
for the nonmoving party. Anderson, 477 U.S. at 252.

III.

DISCUSSION
A.

Fairchild's Motion for Summary Judgment (D.I. 193)
1.

Infringement of Claims 8 and 13 of the '259 Patent

Fairchild argues that there are no genuine disputes of material fact with regard to
infringement of independent claims 8 and 13 of Fairchild's '259 patent by PI's LinkSwitch-II and
LinkSwitch-PH products. According to Fairchild, PI's expert, Dr. Kelley, incorrectly analyzed

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these claims as means-plus-function claims, when only independent claim 1 is in means-plusfunction format. PI responds that Dr. Kelley appropriately analyzed the structural limitations of

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these apparatus claims and, moreover, that the opinions of Fairchild's expert, Dr. Collins, are
internally inconsistent. In PI's view, there is at least a genuine dispute of material fact, making
summary judgment inappropriate.
The Court concludes that summary judgment is not warranted. Dr. Collins' identification
of the requisite "feedback circuit" (the limitation in claims 8 and 13 on which Fairchild's motion
is based) in the accused products is at least arguably inconsistent, as it may be reasonably
interpreted as opining that identical structure in different products both does and does not

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infringe. (See, e.g., D.I. 227, Ex. 1 at 208-13; see also D.I. 195, Ex.Eat~ 185 (Dr. Kelley
explaining that feedback circuitry identified by Dr. Collins for LinkSwitch-II product LNK632,
which Dr. Collins opines cannot meet the feedback circuit limitation, is identical to
corresponding circuitry of other LinkSwitch-II products, which Dr. Collins opines can meet the
feedback circuit limitation)) Because this raises a genuine dispute of material fact, this portion of
Fairchild's summary judgment motion will be denied.

2.

Non-Obviousness of Claim 8 of the '123 Patent

Because PI has withdrawn its obviousness contention with respect to claim 8 of
Fairchild's '123 patent (see D.I. 227, Ex. 2 at 2), this portion of Fairchild's motion will be
granted. (See Tr. at 106)

3.

Validity of the '259 Patent Under 35 U.S.C. § 112

Fairchild argues that PI has failed to show that it can prove, by clear and convincing
evidence, invalidity of any of claims 1-4, 6, and 8-14 of the '259 patent due to lack of
enablement, lack of written description, and/or indefiniteness.
Enablement and written description are required by the first paragraph of 35 U.S.C.

§ 112, which states:
[t]he specification shall contain a written description of the
invention, and the manner and process of making and using it, in
such full, clear, concise, and exact terms as to enable any person
skilled in the art to which it pertains, or with which it is most
nearly connected, to make and use the same.
Compliance with the enablement requirement is a question of law based on underlying factual
findings, and to be satisfied, "[t]he scope of the claims must be less than or equal to the scope of
enablement." Promega Corp. v. Life Techs. Corp., 773 F.3d 1338, 1347 (Fed. Cir. 2014)

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(internal quotation marks omitted). "Compliance with the written description requirement is a
question of fact," Scriptpro, LLC v. Innovation Assocs., Inc., 762 F.3d 1355, 1359 (Fed. Cir.
2014), and to be satisfied the patentee must "convey with reasonable clarity to those skilled in the
art that, as of the filing date sought, he or she was in possession of the invention," New Railhead
Mfg., L.L.C. v. Vermeer Mfg. Co., 298 F.3d 1290, 1295 (Fed. Cir. 2002).

Indefiniteness of claim terms, which is a question oflaw, DDR Holdings, LLC v.
Hotels.com, L.P., 773 F.3d 1245, 1260 (Fed. Cir. 2014), is prohibited by the second paragraph of

35 U.S.C. § 112, which requires that "[t]he specification shall conclude with one or more claims
particularly pointing out and distinctly claiming the subject matter which the applicant regards as
his invention."
As explained below in connection with PI's motion, the Court has decided to grant

summary judgment to PI of invalidity of Fairchild's '259 patent due to anticipation, based in
large part on the Court's rejection of a ±10% limitation on the "substantially constant" current
element of the feedback circuit limitation and its conclusion that Dr. Collins may not provide
testimony on his ± 10% opinion. See infra § 111.B.2. Because PI does not point to any basis for
invalidity under § 112 aside from Dr. Collins' excluded ± 10% opinion (see D.I. 226 at 7-10), PI
has not met its burden to show by clear and convincing evidence that claims 1-4, 6, and 8-11 are
lacking in enablement or written description.
Additionally, PI appears to concede - by the silence of its briefs - that it cannot prove
indefiniteness of any of these claims. (See id. at 6 (PI's brief addressing only written description
and enablement))
Thus, Fairchild will be granted summary judgment of no invalidity of the '259 patent due

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to lack of enablement, lack of written description, or indefiniteness.

4.

Non-Infringement of the '366 Patent

Fairchild argues that it is entitled to summary judgment of non-infringement of PI's '366
patent because PI's expert, Dr. Kelley, does not identify a (1) a soft start latch, (2) a soft start
AND-gate, (3) a frequency variation signal, (4) a pulse width modulation frequency signal, (5) a
power up signal, or (6) a soft start signal, all of which are required by the Court's construction of
the "soft start circuit means," which is a limitation in all of the asserted claims of the '366 patent.
The Court's construction of this term provides, in relevant part: "[t]he corresponding structures
related to the soft start circuit are shown in Figures 3, 6, and 9 of the '366 patent and described in
the specification of the '366 patent at 6:7-17; 6:35-7:18; 11:40-50; and 12:5-10." (D.I. 87 at 14)
More particularly, the following is a portion of the specification the Court incorporated in its
claim construction:
[t]he frequency variation signal 400 is provided to soft start circuit
410. During operation soft start circuit 410 is also provided with
pulse width modulation frequency signal 415 and power up signal
420. . . . Soft start circuit 410 comprises a soft start latch 450 that
at its set input receives the power up signal 420 and its reset input
receives the soft start signal 440. Soft start enable signal 421 is
provided to one input of soft start and-gate 455 while the other
input of soft start and-gate 455 is provided with an output from soft
start comparator 460.
(D.I. 203, Ex.Kat 6:49-52, 7:9-15)
Despite PI's insistence to the contrary, the Court's claim construction does require a
frequency variation signal. (Compare D.I. 87 at 14 (structure is described in '366 patent at, inter

alia, 6:35-7: 18) with '366 patent at 6:49-52 ("The frequency variation signal 400 is provided to
soft start circuit 410.")) Additionally, dependent claims 14 and 21 claim "a frequency variation
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circuit that provides a frequency variation signal." (D.I. 203, Ex.Kat 14:14-17, reexamination
certificate 2:63-64) Thus, dependent claims 14 and 21 further limit claim 9 to a particular source
of the frequency variation signal. Hence, PI's argument that Fairchild's interpretation of the
Court's claim construction would violate the canon of claim differentiation is unpersuasive. See

generally Laitram Corp. v. Rexnord, Inc., 939 F.2d 1533, 1538 (Fed. Cir. 1991) (stating claim
differentiation is "a guide, not a rule").
In the alternative, PI argues that even if a frequency variation signal is required, it or a

structural equivalent is present in Fairchild's accused product. Literal infringement of a meansplus-function limitation requires proof that the accused device performs the identical function
and has a substantially similar structure. See Gen. Protecht Grp., Inc. v. Int 'l Trade Comm 'n,
619 F.3d 1303, 1312 (Fed. Cir. 2010) ("[S]tructure in the accused device constitutes an
equivalent to the corresponding structure in the patent only if the accused structure performs the
identical function in substantially the same way, with substantially the same result."). The scope
of the structural equivalents of a means-plus-function element is a question of fact. See Pressure

Prods. Med. Supplies, Inc. v. Greatbatch Ltd., 599 F.3d 1308, 1316 (Fed. Cir. 2010).
It is undisputed that Fairchild's accused products perform the identical function as the

soft start circuit means; the sole dispute, then, is whether the function is performed in
substantially the same way with substantially the same result as in the '366 patent. (See D.I. 194
at 11) The opinion of PI's Dr. Kelley, for which Dr. Kelley finds support in product testing and
product datasheets, is provided in his Opening Expert Report:
[J]ust like the '366 patent structures, the FAN6756 progressively
increases duty cycle during startup, as described in the product
datasheet, and therefore performs the function in the same way as

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the disclosed structure .... [I]t is my opinion that the FAN6756
soft start functionality also achieves the same result as the
disclosed structure. The '366 specification expressly states that the
soft start function can be implemented using a counter output
signal exactly as used by the FAN6756. ['366 patent at 6:44-48]
In addition, the FAN6756 uses logic circuits like those shown in
the '366 patent to limit the effect of its counter output so that it
controls the duty cycle only during the soft start period. As such,
the structure of the FAN6756 is, at the very least, an
interchangeable structure as that disclosed in the '366 patent.
(D.I. 227, Ex. 4 at 12-16) Dr. Kelley further explains that "the FAN6756 uses logic circuits like
those shown in the '366 patent to limit the effect of its counter output so that it controls the duty
cycle only during the soft start period." (See D.I. 227, Ex. 4 at 16)2 The Court finds that these
opinions create a genuine dispute of material fact as to whether the accused products include
structural equivalents for the various components of the soft start circuit means.
Accordingly, the Court will deny Fairchild's motion for summary judgment of noninfringement of the '366 patent.

5.

Non-Infringement of the '587 Patent

Fairchild argues that it is entitled to summary judgment of non-infringement of PI's '587
patent because PI fails to identify how the accused products meet the "current input circuit"
limitation of every asserted claim. The Court construed "current input circuit" as "a circuit that
receives a current and produces or generates an output signal in response to the received current;
a 'current input circuit' does not include voltage dividers and other circuits that monitor

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Although unnecessary to defeat summary judgment, Dr. Kelley's opinion regarding the
soft start latch and AND-gate (see D.I. 204, Ex.Vat iMf 74-75), which would otherwise support
his infringement opinion, is unavailing as a result of PI's repeated representations that this
opinion is not a part of Dr. Kelley's affirmative infringement opinions, but rather merely rebuttal
to Fairchild's design around story (see, e.g., D.I. 294 at 62; D.I. 305 at 5-6), which the Court has
found to be inadmissible (see D.I. 331 at 3-4; see also Pretrial Conference Transcript).
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voltage, although a 'current input circuit' may receive a current that is representative of a
voltage." (D.1. 87 at 22) (emphasis added) Fairchild contends that, in contradiction to the
Court's claim construction, PI's Dr. Kelley has relied in his infringement analysis exclusively on
voltage dividers and circuits that monitor voltage.
Fairchild's Dr. Wei explains that all of the accused current input circuits are actually
voltage dividers or other circuits that monitor voltage. (D.1. 203, Ex. I at iMf 124-40) With
respect to Fairchild's F AN6756 product group, Dr. Kelley identifies the circuitry coupled to the
HV input pin as the current input circuit (D.I. 204, Ex.Vat iMf 101, 108-17), even though the
datasheet for the F AN6756 expressly identifies this circuit as a voltage divider (see D.I. 203, Ex.
Sat 11), as is confirmed by Fairchild's witnesses (see D.I. 204, Ex.Vat iMf 108-17). The Court's
construction excludes "voltage dividers." Similarly, for Fairchild's SG6841 product group, Dr.
Kelley identifies the circuitry coupled to the VIN input pin as the current input circuit (see id. at

iMf 102, 106-07), even though U.S. Patent No. 6,611,439 ("the '439 patent") - which Dr. Kelley
agrees describes the accused circuitry in the SG6841 product group (see id. at iMf 106-07; D.I.
204, Ex.Wat 167)- states that "[t]he first comparator 30 will compare the voltage VS and the

voltage Vlimit" (D.I. 204, Ex. X at 4:50-51 & Fig. 2) (emphasis added). The Court's
construction excludes "other circuits that monitor voltage."
Dr. Kelley explains why he does not believe the accused circuits consist of voltage
dividers or other circuits that monitor voltage; his view is, rather, that they consist of circuits that
receive currents representative of a voltage. (See D.I. 204, Ex. Vat iMf 106-17) In doing so, Dr.
Kelley relies on the final portion of the Court's construction, which provides "a 'current input
circuit' may receive a current that is representative of a voltage." (D.I. 87 at 22) This is

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unavailing. Dr. Kelley's infringement analysis impermissibly seeks to broaden the Court's claim
construction to mean that a circuit that "receive[ s] a current that is representative of a voltage" is
not a voltage divider or a circuit that monitors voltage, and therefore satisfies the "current input
circuit" limitation. This position was rejected by the International Trade Commission - whose
construction of the "current input circuit" term formed the basis for this Court's construction.

(See D .I. 87 at 2 (citing In re Certain Power Supply Controllers, 2008 ITC LEXIS 773, at *3 7-4 7
(USITC May 1, 2008)) Moreover, it is inconsistent with PI's representations during claim
construction that this final element of the claim construction was simply "clarifying language"
and not intended to override the other limitations in the construction. (See D.I. 69 at 14)
In short, neither Dr. Kelley nor PI provide a basis on which a reasonable finder of fact
could find that what have been described - prior to the instant litigation - as voltage dividers or
currents that monitor voltage are, in fact, not. Accordingly, the Court will grant Fairchild's
motion for summary judgment that the accused products do not infringe the asserted claims of
PI's '587 patent. 34

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While the parties do not specifically address the FL6300A product group in their briefs,
both experts address it in their infringement analyses. (See D.I. 203, Ex. I at iMf 135-40; D.I. 204,
Ex.Vat if 103; D.I. 227, Ex. 3 at Ex. 6) Because Dr. Kelley's infringement analysis for this
product group does not address the evidence presented by Dr. Wei that the FL6300A uses a
voltage divider (see D.I. 203, Ex. I at iMf 135-40), but merely points to deposition testimony in
support of his conclusion that "[t]he FL6300A includes a control circuit coupled to receive the
current limit adjustment signal" (D.I. 227, Ex. 3 at Ex. 6 at 9-10, 12-19, 25-26))- a conclusion
that appears to be similarly based on an impermissiblybroad reading of the Court's claim
construction for "current input circuit" - the Court's conclusion applies equally to the FL6300A
product group.
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Literally as this opinion was being printed and prepared for docketing, the Court became
aware that this same afternoon PI submitted a letter, indicating that it has "decided not to go
forward at trial on the '587 patent." (D.I. 337)
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6.

Invalidity of Claims 29 and 31 of the '359 Patent

Fairchild argues that independent claim 29 and dependent claim 31 of PJ's '359 patent are
invalid due to lack of written description support for a "response agnostic" controller. (D.I. 194
at 29) Fairchild further asserts that "PI disclaimed coverage for control circuits that lacked
responsiveness." (Id. (citing D.I. 204, Ex. BB at 1:48-58))
PI responds that the specification only references unresponsiveness once, in the context of
the embodiment disclosed in Figure 1 of the patent. (See D.I. 226 at 22-23 (citing D.I. 204, Ex.
BB at 6:49)) PI adds that "there are numerous other embodiments which are described elsewhere
in the specification without mentioning unresponsiveness at all . . . . There is, thus, nothing in
the specification that precludes the claimed invention of claim 29 from 'render[ing] dormant the
drive signal generator' ... without being unresponsive to the energy requirements of the load."
(Id. at 23 (quoting D.I. 204, Ex. BB at 18:16))

Neither party cites any expert opinion or, indeed, any evidence other than the patent itself,
as well as caselaw and attorney argument. 5 Under the circumstances, including the complexity of
the technology, the Court concludes that a reasonable factfinder could find that Fairchild has
proven invalidity by clear and convincing evidence - but, alternatively, could find that Fairchild
has failed to meet this heavy burden. Hence, summary judgment is not warranted and the Court
will deny Fairchild's motion with respect to invalidity of claims 29 and 31 of PJ's '359 patent.

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As stated above, "[ c]ompliance with the written description requirement is a question of
fact," Scriptpro, 762 F.3d at 1359, requiring the patentee to "convey with reasonable clarity to
those skilled in the art that, as of the filing date sought, he or she was in possession of the
invention," New Railhead Mfg., 298 F.3d at 1295.
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B.

Pl's Motion for Summary Judgment (D.I. 196)
1.

No Infringement Under the Doctrine of Equivalents

PI argues that Fairchild is barred from asserting infringement by the doctrine of
equivalents ("DOE") for any of its patents because Fairchild's DOE infringement contentions
have been stricken by the Court as untimely. PI is correct. (See D.I. 162; D.I. 183) However,
because the Court has also ruled that PI is barred from relitigating the direct infringement of the
'972 patent by the LinkSwitch-11 in a power supply with a transformer (D.I. 328), PI's motion is
effectively moot with regard to the '972 patent. Accordingly, the Court will grant PI's motion
for summary judgment of no infringement under the doctrine of equivalents as it relates to all of
Fairchild's asserted patents except for the '972 patent.

2.

Anticipation of Claims 1-4, 6, and 8-14 of the '259 Patent

PI argues that claims 1-4, 6, and 8-14 of Fairchild's '259 patent are invalid as anticipated
by PI's LNK520 datasheet, and that claims 8-14 are also invalid as anticipated by Fairchild's own
'972 patent. PI's arguments turn on the "substantially constant" current element of the "feedback
circuit" limitation - "a feedback circuit coupled to the control circuit and the transformer, the
feedback circuit operable to support regulation by the control circuit from the primary side so that
the current provided to the load at the output terminal is substantially constant." (D.I. 195, Ex.
D at 7:20-24) (emphasis added) Fairchild conceded at the hearing that the "substantially
constant" current element of the "feedback circuit" limitation is the only element it disputes as
missing from the prior art. (See Tr. at 162, 164) The Court finds that PI has established that no
reasonable juror could reach any conclusion other than that all of the limitations of the '259
patent are found in a single prior art reference. (See D.I. 200, Ex. D at Ex. 5 (Dr. Kelley's

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anticipation analysis for claims 1-4, 6, and 8-14 with regard to LNK520 datasheet); D.I. 200, Ex.
D at Ex. 4 (Dr. Kelley's anticipation analysis for claims 8-14 with regard to '972 patent))
Dr. Collins opines that the feedback circuit limitation is not found in the prior art because
"[ o]ne of ordinary skill in the art at the time the '259 patent was invented would understand
'substantially constant current' to mean ±10% or less at the output terminal. ... [And] Power
Integrations' LNK520 was incapable of providing a constant current of± 10% or less at the
output terminal." (D.I. 202, Ex. 3 at if 45) In PI's view, Dr. Collins impermissibly narrows the
"substantially constant" term. PI instead urges the Court to construe "the current ... is
substantially constant" to expressly exclude any numerical limitations.
The Court agrees with PI that determining how one of ordinary skill in the art would
understand "substantially constant current" in the '259 patent presents an issue of claim
construction. See 02 Micro Int'/ Ltd. v. Beyond Innovation Tech. Co., Ltd., 521 F.3d 1351, 1362
(Fed. Cir. 2008). The scope of the claims is a question oflaw for the Court to decide, not a jury.

See id. The Court disagrees with Fairchild's contention that Dr. Collins is merely providing his
expert opinion on a factual dispute; i.e., whether the "substantially constant" claim element of the
'259 patent is present in the prior art. Instead, he is first construing that term narrowly, limited to
±10%, and then applying that construction to determine whether it is found in the prior art. (See
D.I. 224 at 1-2 (Fairchild arguing in brief about "the plain and ordinary meaning of 'substantially
constant current,"' i.e., an issue of claim construction); id. at 9 (attacking PI for purportedly
"flawed and impermissibly broad reading of the '259 patent claims," i.e., an issue of claim

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construction))6
Turning to the proper construction of "substantially constant," the Court again agrees
with PI. 7 Dr. Collins arrived at the numerical limit because, from the perspective of"a person of
ordinary skill in the art, [his] opinion is that the plus or minus 10 percent level is what one would
assume something was inventive at the time of the '259 patent [and] would have felt to be
substantially constant current." (D .I. 202, Ex. 9 at 21; see also id. at 16-1 7) Putting aside

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Fairchild analogizes the instant situation to one the Court confronted in earlier litigation
between these parties, where the Court concluded a particular dispute was not merely one of
claim construction but also a factual dispute that had to be presented to a jury. (See D.I. 224 at
14 (citing Power Integrations, Inc. v. Fairchild Semiconductor Int'/, Inc., 763 F. Supp. 2d 671,
681-83 (D. Del. 2010) ("Fairchild II"))) The situation in Fairchild II was at least somewhat
different because the Court was addressing cross-motions for summary judgment on the issue in
dispute (after concluding that supplemental claim construction was required). In any event,
regardless of the degree of similarity, the Court is not persuaded that how it handled the issue in
Fairchild II requires or even strongly supports taking the same approach here.
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Fairchild argues that it is too late for PI to ask the Court to construe an additional claim
term, but the Court disagrees. See, e.g., Fairchild II, 763 F. Supp. 2d at 681-82. Further,
Fairchild suggests that it has not briefed the proper construction of"substantially constant,"
because the term was not in dispute during the claim construction process and because Fairchild
rejects PI's view that Dr. Collins' opinion amounts to a claim construction (as opposed to
invalidity) opinion. (See, e.g., D.I. 224 at 9 ("But this is not a claim construction dispute as
evidenced by both parties' failure to propose construction of this limitation during the exhaustive
claim construction process in this case.")) Under the circumstances - including that Fairchild
insists ''the ordinary meaning of 'substantially constant current' is readily understood and thus
not disputed" (D.I. 224 at 13) and, thus, presumably requires no additional briefing; that Fairchild
has not expressly asked to file a claim construction brief (see D.I. 224 at 12 n.5 ("Fairchild will
not brief this claim construction issue unless the Court determines that additional claim
construction briefing is required")), relying instead on its position that the Court should not now
construe the "substantially constant" term; that Fairchild had an opportunity to put its claim
construction arguments in the extensive briefing on summary judgment; that the Court is basing
its construction on the intrinsic evidence (which cannot change); and that Fairchild has
presumably already put in the record its best extrinsic evidence (i.e., Dr. Collins' opinion) yet has
failed to persuade the Court to adopt Dr. Collins' proposed construction- the Court concludes
that it can construe "substantially constant" without now providing Fairchild leave to file a
supplemental claim construction brief.
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whether this is mere conclusory (and inadmissible) expert opinion, it is indisputably extrinsic
evidence, and when weighed against the intrinsic evidence it does not persuade the Court to
adopt a construction as precise or narrow as Fairchild proposes. As even Dr. Collins
acknowledges, the ±10% limitation is not found anywhere in the '259 patent. (See id. at 14-15;
see also D.I. 202, Ex. 18 at 198 (Dr. Kelley stating, "with regard to the plus or minus 10 percent,

I don't see where Dr. Collins has provided really any basis for introducing that number")) Dr.
Collins did not identify any evidence, other than his own opinion, to support his definition of
"substantially constant." (See D.I. 202, Ex. 9 at 16-21)
The Court will adopt PI's proposed construction of "the current ... is substantially
constant": "an output current that is maintained largely but not wholly at a constant level and is
not bounded by a specific numerical value." In the Court's view, this is the plain and ordinary
meaning of the term at the time of the invention (and even Fairchild agrees "[t]here can be little
doubt that words such as this that have a changing scope over time should be afforded their plain
and ordinary meaning at the time of the invention") (D .I. 224 at 11) (emphasis omitted). See
Anchor Wall Sys., Inc. v. Rockwood Retaining Walls, Inc., 340 F.3d 1298, 1310-11 (Fed. Cir.

2003) ("[W]ords of approximation, such as ... 'substantially,' are descriptive terms commonly
used in patent claims to avoid a strict numerical boundary to the specified parameter.") (internal
quotation marks omitted); see also Ecolab, Inc. v. Envirochem, Inc., 264 F.3d 1358, 1367 (Fed.
Cir. 2001).
Given the Court's construction of the "substantially constant" term, the Court concludes
that Fairchild has failed to raise a genuine dispute of material fact to avoid summary judgment of
invalidity of claims 1-4, 6, and 8-14 of the '259 patent. On this record, including the opinion of
15

Dr. Collins, a reasonable jury could only find that the feedback circuit limitation, including its
subsidiary "substantially constant" current limitation, was disclosed by either the LNK520 or the
'972 patent. See generally Sitrick v. Dreamworks, LLC, 516 F.3d 993, 1001 (Fed. Cir. 2008)
("Conclusory expert assertions cannot raise triable issues of material fact on summary
judgment.").

In particular, Dr. Collins does not dispute that the LNK520 datasheet is the commercial
embodiment of U.S. Patent No. 6,480,399 ("the '399 patent"). (See D.I. 202, Ex. 3 at if 131) It is
further undisputed that during prosecution the Examiner rejected all of the original claims of the
'259 patent as anticipated by the '399 patent. (See D.I. 202, Ex. 10 at 2-7) The Examiner found
that all of the limitations of the original independent claims, including the requirement of a
substantially constant current output, were present in the '399 patent. (See id.) The claims were
ultimately allowed only after Fairchild amended each independent claim to require a
three-winding transformer (see D.I. 202, Ex. 11), which the Examiner had noted that the prior art
he had before him did not disclose (see D.I. 202, Ex. 10 at 8). Fairchild cannot genuinely dispute
that the LNK520 datasheet, which was not before the Examiner, but undisputedly includes a
three-winding transformer (see D.I. 197 at 11-12) (referring to D.I. 202, Ex. 6), discloses a
substantially constant current.
With respect to the prior art '972 patent, the inventor of that patent, Mr. Yang, agreed that
in the '972 patent, "[t]he feedback circuit is operable to support regulation by the control circuit
from the primary side so that the current provided to the load at the output terminal is
substantially constant." (D.I. 202, Ex. 15 at 235) Similarly, the inventor of the '259 patent, Mr.
Weirich, testified that the '972 patent "refer[ s] to providing a power converter having
16

substantially constant output current." (D.I. 202, Ex. 13 at 93-94) Mr. Weirich further explained
that Figure 1 of the '972 patent shows that "one of the functionalities provided by the application
circuit Figure 1 would be to be providing a substantially constant regulated current at its output

10." (Id. at 96-97)
Notwithstanding this unrebutted inventor testimony, Dr. Collins opines:
Since the structures of the '972 patent do not have direct
measurement of the output current and uses indirect measurement
through feedback variables which are subject to error and
tolerance, and there is no compensation for these potential sources
of error, the system in the Yang '972 patent cannot regulate current
to be substantially constant (±10% or less) .... The Yang '972
patent does not disclose or suggest a circuit capable of achieving a
substantially constant current at the output terminal being ±10% or
less. In fact, the Yang '972 patent fails to disclose any specific
value of constant current. As such, the Yang '972 patent fails to
disclose the aforementioned claim limitations.
(D.I. 225, Ex. A at iMf 90-91) However, given the Court's construction, the feedback circuit
limitation does not require that the current remains constant within the range of± 10%.
Accordingly, the Court will grant PI's motion for summary judgment of invalidity of
claims 1-4, 6, and 8-14 of the '259 patent as anticipated by the LNK520 datasheet, as well as of
claims 8-14 as anticipated by the '972 patent.

3.

No Literal Infringement of the '123 Patent
by the Accused LinkSwitch-PH Products

Finally, PI seeks summary judgment of no literal infringement of Fairchild's '123 patent
by the LinkSwitch-PH products because Fairchild's timely contentions do not identify an "output
terminal" as required by the Court's claim construction. The Court construed "generating a LED
current for controlling the LED" in claim 8 of the ' 123 patent as "producing at an output terminal

17

of the control circuit a current for controlling the LED." (D.I. 88) Fairchild only identifies the
DRAIN pin as the output terminal, but this contention has been stricken as untimely. (See D.I.
162; D.I. 183) Accordingly, the Court will grant PI summary judgment of no literal infringement
of Fairchild's '123 patent.

IV.

CONCLUSION
An appropriate Order follows.

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