Opinion ID: 856284
Heading Depth: 2
Heading Rank: 2

Heading: soft start circuit

Text: The district court construed the term “soft start circuit” in the ’851 and ’366 Patents as means-plus-function limitations under paragraph 6 of 35 U.S.C. § 112 (now 35 U.S.C. § 112(f)). In the district court’s view, an ordinarily skilled artisan would not “know the precise structures for a soft start circuit, because the function of a soft start circuit can be achieved in a variety of ways making it unclear what the specific structures are for performing the recited functions.” Power Integrations, Inc. v. Fairchild Semiconductor Int’l, Inc., 422 F. Supp. 2d 446, 459 (D. Del. 2006). Thus, the district court concluded that “the term ‘soft start circuit’ should be construed in accordance with Section 112, ¶ 6” and limited to the structure described in the specification and its equivalents. Id. at 460. On appeal, Fairchild argues that the district court incorrectly construed the “soft start circuit” limitations in the ’851 and ’366 Patents as means-plus-function limitations. Fairchild contends that these limitations do not include the word “means,” which creates a strong presumption that mean-plus-function claiming does not apply. Rather, Fairchild argues, the claims disclose sufficient structure to remove the “soft start circuit” limitations from the reach of means-plus-function claiming. Power Integrations seeks an affirmance of the district court’s construction. Power Integrations argues that the term “soft start circuit,” does not suggest sufficiently definite structure to the skilled artisan. Power Integrations would have us affirm the district court’s construction and limit the term “soft start circuit” to the structures described in the specifications of the ’851 and ’366 Patents. POWER INTEGRATIONS v. FAIRCHILD SEMI 22 Means-plus-function limitations permit a patentee to claim an element of her invention in terms of the element’s function, without in the claim itself reciting corresponding structure: An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the correspond- ing structure, material, or acts described in the specification and equivalents thereof. 35 U.S.C. § 112, ¶ 6.2 If a claim term does not use the word “means,” we presume that means-plus-function claiming does not apply. See CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, 1369 (Fed. Cir. 2002). If, however, the claim term recites a function without reciting sufficient structure for performing that function, the presumption falls and means-plus-function claiming applies. See, e.g., Watts v. XL Sys., Inc., 232 F.3d 877, 880 (Fed. Cir. 2000). We assess whether a claim limitation recites sufficient structure to avoid means-plus-function claiming from the vantage point of an ordinarily skilled artisan. See Inventio, 649 F.3d at 1357; Apex Inc. v. Raritan Computer, Inc., 325 F.3d 1364, 1372 (Fed. Cir. 2003). To this end, “considering intrinsic and extrinsic evidence is usually helpful [in determining whether] a claim limitation is so devoid of structure that the drafter 2 In 2011, Congress reformatted the paragraphs of § 112 as subsections. Leahy-Smith America Invents Act (“AIA”), Pub. L. No. 112-29, 125 Stat. 284 (2011). Section 112, ¶ 6, is now codified as § 112(f). To maintain consistency with the district court’s opinion, we refer to § 112, ¶ 6. 23 POWER INTEGRATIONS v. FAIRCHILD SEMI constructively engaged in means-plus-function claiming.” Inventio, 649 F.3d at 1357. With respect to intrinsic evidence, a patent’s specification may inform the skilled artisan’s understanding of the structure required by a claim limitation. We have previously held on several occasions that the term “circuit” connotes structure. See MIT v. Abacus Software, 462 F.3d 1344, 1355 (Fed. Cir. 2006) (“[D]ictionary definitions establish that the term ‘circuitry,’ by itself, connotes structure.”); see also Linear Tech. Corp. v. Impala Linear Corp., 379 F.3d 1311, 1320–21 (Fed. Cir. 2004) (holding that the term circuit is not a means-plus-function limitation when the patent provides “a recitation of the respective circuit’s operation in sufficient detail to suggest structure to persons of ordinary skill in the art”); Apex, 325 F.3d at 1373 (“[T]he term ‘circuit’ with an appropriate identifier such as ‘interface,’ ‘programming’ and ‘logic,’ certainly identifies some structural meaning to one of ordinary skill in the art.”). In Abacus, we said, The claim language here too does not merely de- scribe a circuit; it adds further structure by de- scribing the operation of the circuit. The circuit’s input is “appearance signals” produced by the scanner; its objective is to “interactively introduce[e] [sic] aesthetically desired alterations into said appearance signals”; and its output is “modified appearance signals.” This description of the operation of the circuit is sufficient to avoid 112 ¶ 6. 462 F.3d at 1356 (citation omitted). Abacus establishes that in determining whether the word “circuit” invokes means-plus-function claiming, the POWER INTEGRATIONS v. FAIRCHILD SEMI 24 pivotal issue is “whether the [circuit limitation] as properly construed recites sufficiently definite structure.” Personalized Media Commc’ns., LLC v. Int’l Trade Comm’n, 161 F.3d 696, 704 (Fed. Cir. 1998) (emphasis added). A description of the circuit’s operation may provide sufficiently definite structure, Abacus, 462 F.3d at 1356, as can certain “adjectival qualifications,” Apex, 325 F.3d at 1374 (“interface circuit”). Nevertheless, not just any adjectival qualification or functional language will suffice. See Abacus, 462 F.3d at 1362–63 (Michel, C.J., dissenting). The proper inquiry is whether the claim limitation itself, when read in light of the specification, connotes to the ordinarily skilled artisan sufficiently definite structure for performing the identified functions. Apex, 325 F.3d at 1373.
Turning to the claims at issue, claim 4 of the ’851 Patent recites a “soft start circuit” that performs a function: a soft start circuit that provides a signal instructing said drive circuit to discontinue said drive signal when said magnitude of said oscillation signal is greater than a magnitude of said frequency var- iation signal. ’851 Patent col. 12 ll. 46–49 (emphasis added). Although the claim includes a functional description of the “soft start circuit,” the claim does not include the word “means.” Further, the claimed “soft start circuit” performs a straightforward function when a simple test is met: it “provides a signal” that cuts off the drive signal “when said magnitude of said oscillation signal is greater than a magnitude of said frequency variation signal.” This test is nothing more than a comparison of the magnitudes of two signals. The end result is simple: if the 25 POWER INTEGRATIONS v. FAIRCHILD SEMI comparison is met, an “off” signal is provided. The word “circuit” in combination with such a clear and unambiguous description of the circuit’s operation weighs heavily in favor finding sufficient structure to avoid means-plusfunction claiming. The district court expressed concern that an ordinarily skilled artisan would not “know the precise structures for a soft start circuit, because the function of a soft start circuit can be achieved in a variety of ways.” Power Integrations, 422 F. Supp. 2d at 459. Yet, we require only that the claim term be used in common parlance or by ordinarily skilled artisans to designate sufficiently definite structure, “even if the term covers a broad class of structures.” Lighting World, 382 F.3d at 1359–60. Here, as the district court pointed out, a variety of structures can be used to provide the claimed function. Nevertheless, viewed in the context of the claimed invention, the function recited is sufficiently clear, and definitely described, to suggest to the ordinarily skilled artisan a defined class of structures. As in Abacus, we have an input to the circuit (the oscillation and frequency variation signals), a straightforward function (comparing of the magnitudes of these signals), and an output (the signal provided to the drive circuit based on the comparison). This is sufficient structure in the context of the claimed invention to avoid the ambit of means-plus-function claiming. The “soft start circuit” limitation of claim 4 of the ’851 Patent, therefore, recites sufficient structure to avoid means-plus-function claiming. The district court erred in construing this term as a means-plus-function limitation under § 112, ¶ 6. POWER INTEGRATIONS v. FAIRCHILD SEMI 26
We turn next to claims 9 and 14 of the ’366 Patent. Claim 9 also includes a “soft start circuit”: a soft start circuit that provides a signal instructing said drive circuit to disable said drive signal during at least a portion of said maximum time period. ’366 Patent col. 13 ll. 33–35 (emphasis added). Claim 14 depends from claim 9 and is therefore subject to the same limitation. This “soft start circuit” in the ’366 patent, like the soft start circuit in claim 4 of the ’851 Patent, provides a signal that cuts off the drive signal. The claim further informs us that the soft start circuit provides the cutoff signal “during at least a portion of said maximum time period.” While we agree that this functional description is less illuminating than that recited in claim 4 of the ’851 patent, we find that it suggests sufficient structure to an ordinarily skilled artisan. Power Integrations conceded that a skilled artisan would understand the claim limitation as referring to “various soft start circuit structures [which] accomplish the functions recited in the patent claims . . . .” J.A. 358. As such, an ordinarily skilled artisan reading the claim limitation in the context of the claimed invention, and in light of the specification, would understand that the limitation connotes “sufficiently definite structure for performing the identified functions.” Apex, 325 F.3d at 1373. Having concluded our review of claim construction, we reverse the district court’s construction of the “soft start circuit” limitations in claim 4 of the ’851 Patent and in claims 9 and 14 of the ’366 patent. On remand, the dis27 POWER INTEGRATIONS v. FAIRCHILD SEMI trict court shall construe those claims according to our instructions and assess what effects, if any, the new constructions have on the validity of those claims and on Fairchild’s infringement thereof. If the court determines that its constructions raise new, material issues of validity or infringement, the court shall determine whether to order a new trial. The court shall determine whether any such new, material issues are “distinct and separable” such that a new trial limited to those issues would not unduly prejudice either party. Cf. Gasoline Prods. Co. v. Champlin Ref. Co., 283 U.S. 494, 500 (1931). If, in its discretion, the district court finds that any such new, material issues may be tried separately without prejudice, the court may limit any new trial accordingly. The court should consider the effects of any amendments made in reexamination.