Close but no cigar: ITC gets 4 of 5 claim constructions correct, but must reconsider 2 issuesJune 15, 2009

In a recent decision, the Federal Circuit addressed a variety of claim construction, infringement, and validity issues in an appeal from the International Trade Commission. After construing five disputed claim terms, the ITC held one of four representative products infringed, the remaining three did not infringe, and one claim invalid as anticipated. Both parties appealed.The Federal Circuit affirmed in part, reversed in part, and remanded. The court affirmed the ITC's construction of 4 of the 5 disputed terms. However, the modification of one term resulted in the court vacating the ITC's determination of invalidity of one claim, as well as infringement of two of the four devices. The Federal Circuit affirmed the finding of noninfringement of the other two devices, and remanded for reconsideration of the various issues in light of the revised construction.More detail of Linear Tech. Corp. v. Int'l Trade Comm'n after the jump.Linear Technology Corporation ("Linear") owns a patent covering technology relating to voltage regulators for use in electronic devices. Specifically, the patent is directed to two improvements in such devices. First, the patent addresses increased efficiency by having a device enter a "sleep mode," where power required from a power source (such as a battery) is reduced during periods of lower usage. Second, the patent addresses prevention of "reverse current" situations where power is drawn back from the device and eventually lost. Linear filed a complaint with the United States International Trade Commission ("the ITC") under section 337 of the Tariff Act of 1930, 19 U.S.C. § 1337(a)(1)(B), alleging Advanced Analogic Technologies, Inc. ("AATI") imported and/or sold for importation certain electronic voltage regulators that infringed the patent. Before the ITC, the parties stipulated that four devices would be considered representative of AATI's devices. Linear alleged all four devices infringed claims 2, 3, and 34, which related to the "sleep mode" aspect of the patent; Linear alleged two devices infringed claim 35, which related to the "reverse current" aspect of the patent. After construing five claim limitations, the ITC held one of the four devices infringed the "sleep mode" claims, the remaining devices did not infringe, and that claim 35 was anticipated. Both AATI and Linear appealed. The case turned largely on claim construction. The Federal Circuit affirmed the ITC's constructions of four of the five limitations, generally construing the claims broadly. For instance the court affirmed the ITC's construction of "a second control signal . . . to cause both transistors to be OFF," which did not require the second control signal to "directly cause" both transistors to be OFF. The court reasoned that such a direct causation requirement would encourage infringers to avoid liability by claiming some intervening signal breaks chain of causation. The court thus rejected AATI's argument that because its device relied on an intermediary signal to turn OFF the transistors, it did not practice Linear's patent.The court also affirmed the ITC's construction that "first state of circuit operation" and "second state of circuit operation" could refer to operation in a specific condition (such as low current load) but were not necessarily limited to that condition. As stated by the court: "Even in situations when only one embodiment is disclosed, the claims generally should not be narrowed to cover only the disclosed embodiments or examples in the specification." Here, the specification provided examples where the first state would be operating in low current conditions, but the court held this should not be interpreted to limit the first state to operation in low current state conditions.

AATI contested the construction of the term "switch . . . including a pair of synchronously switched switching transistors" despite having explicitly defined this phrase in the specification. The Federal Circuit held the explicit definition from the specification (adopted by the ITC) was clearly proper.In the one instance where the ITC construed a claim narrowly, the court reversed, adopting instead a broader construction. The ITC construed the claim limitation "monitoring the current to the load" to exclude monitoring voltage. The court held this was improperly narrowing the claim, observing the "patent not only discloses monitoring current directly by using a current comparator . . . but also indirectly by some other means." Further, one skilled in the art would know that Ohm's law could be used to measure current indirectly by measuring voltage across a resistor. As a result, the court held the proper construction of the claim should include monitoring the current load indirectly via voltage as "some other means." The court concluded: "because there is no basis in the patent specification for adding the negative limitation—excluding monitoring voltage—we hold that the Commission erred in construing this limitation." This modification of the construction of this term affected the ITC's invalidity determination as well. It was undisputed that a product sold before the patent's priority date disclosed all elements of claim 35. However, the ITC held Linear could not prove earlier reduction to practice because it had not directly monitored current as required under its now-reversed construction. The court held Linear's prior indirect measurement of current via voltage could constitute a reduction to practice sufficient to preclude invalidation of the claim as anticipated by prior art. However, the court remanded the issue for the ITC to determine if any other limitations of claim 35 were not present in Linear's alleged reduction to practice, which could independently prevent Linear from eliminating the product as prior art.To read the full decision in Linear Tech. Corp. v. Int'l Trade Comm'n, click here.

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