Power Integrations, Inc. v. Lee

• Decision Date: 12 August 2015
• Docket Number: No. 2014–1123.,2014–1123.
• Citation: 116 U.S.P.Q.2d 1137,797 F.3d 1318
• Parties: POWER INTEGRATIONS, INC., Plaintiff–Appellant v. Michelle K. LEE, Director, U.S. Patent and Trademark Office, Defendant–Appellee.
• Court: U.S. Court of Appeals — Federal Circuit

797 F.3d 1318

116 U.S.P.Q.2d 1137

POWER INTEGRATIONS, INC., Plaintiff–Appellant

v.Michelle K. LEE, Director, U.S. Patent and Trademark Office, Defendant–Appellee.

No. 2014–1123.

United States Court of Appeals, Federal Circuit.

Aug. 12, 2015.

Howard G. Pollack, Fish & Richardson, P.C., Redwood City, CA, argued for plaintiff-appellant. Also represented by Michael R. Headley ; Craig E. Countryman, San Diego, CA; Frank Scherkenbach, Boston, MA.

Amy J. Nelson, Office of the Solicitor, United States Patent and Trademark Office, Alexandria, VA, argued for defendant-appellee. Also represented by Nathan K. Kelley, Scott Weidenfeller.

Before MOORE, MAYER, and LINN, Circuit Judges.

Opinion

MAYER, Circuit Judge.

Power Integrations, Inc. (“Power Integrations”) challenges a decision of the Board of Patent Appeals and Interferences (“board”) affirming the rejection of claims 1, 17, 18, and 19 of U.S. Patent No. 6,249,876 (the “'876 patent”) as anticipated under 35 U.S.C. § 102(b). See Ex parte Powers Integration, Inc., No. 2010–011021, 2010 WL 5244756 (B.P.A.I. Dec. 22, 2010) (“Power Integrations III ”). For the reasons discussed below, we vacate and remand.

Background

The '876 patent is entitled “Frequency Jittering Control for Varying the Switching Frequency of a Power Supply.” It is directed to a technique for reducing electromagnetic interference by jittering the switching frequency of a switched mode power supply. See '876 patent col.1 ll.66–67. Claim 1, as amended, recites:

A digital frequency jittering circuit for varying the switching frequency of a power supply, comprising:

an oscillator for generating a signal having a switching frequency, the oscillator having a control input for varying the switching frequency;

a digital to analog converter coupled to the control input for varying the switching frequency; and

a counter coupled to the output of the oscillator, the digital to analog converter coupled to the counter, the counter causing the digital to analog converter to adjust the control input and to vary the switching frequency of the power supply.

J.A. 710.

Claims 17, 18, and 19 relate to a method for varying the switching frequency using a varying voltage to control the oscillator. '876 Patent col.9 ll.37–52. Independent claim 17, as amended, requires “cycling a counter” to generate a secondary voltage that varies over time:

A method for generating a switching frequency in a power conversion system, comprising:

generating a primary voltage;

cycling a counter coupled to one or more secondary voltage sources to generate a secondary voltage which varies over time; and

combining the secondary voltage with the primary voltage to be received at a control input of a voltage-controlled oscillator for generating the switching frequency of the power conversion system which is varied over time.

J.A. 713.

In 2004, Power Integrations brought suit against Fairchild Semiconductor International, Inc. and related parties (collectively “Fairchild”) in the United States District Court for the District of Delaware. It alleged that Fairchild had willfully infringed the '876 patent, as well as United States Patent Nos. 4,811,075, 6,107,851, and 6,229,366. See Power Integrations, Inc. v. Fairchild Semiconductor Int'l, Inc., 422 F.Supp.2d 446, 448 (D.Del.2006), aff'd in part, rev'd in part,

711 F.3d 1348 (Fed.Cir.2013) (“Power Integrations I ”). During claim construction proceedings, Power Integrations argued that the term “coupled” in claim 1 of the '876 patent, when read in light of the specification and surrounding claim language, required that two circuits be connected in a manner “such that voltage, current, or control signals pass from one to another.” Id. at 455. It further contended that the “recited coupling” between the counter and the digital to analog converter must be “present for the purposes of control.” Id. (citations and internal quotation marks omitted). Power Integrations made clear, however, that its proposed construction did not require a direct connection between circuit elements. Id. The district court adopted Power Integrations' proposed claim construction, concluding that it was “consistent with the claim language and the context of the specification which describes the purpose for which various parts of the claimed invention are coupled.” Id. at 456. The court emphasized, moreover, that its construction of the term “coupled” did not “require a direct connection or ... preclude the use of intermediate circuit elements.” Id. In the wake of the trial court's claim construction, Fairchild withdrew its anticipation defense, instead arguing at trial that U.S. Patent No. 4,638,417 (“Martin”) rendered claim 1 obvious.

In 2006, the trial court bifurcated the litigation, separating issues of infringement and damages from issues related to patent validity. A first jury found that Fairchild had willfully infringed claim 1 of the '876 patent, as well as several claims of the other asserted patents. After a trial on validity, a second jury returned a verdict that claim 1 of the '876 patent was not obvious in view of Martin.

On appeal, this court affirmed the jury's finding that claim 1 of the '876 patent was not invalid for obviousness. See Power Integrations, Inc. v. Fairchild Semiconductor Int'l, Inc., 711 F.3d 1348, 1366–69 (Fed.Cir.2013) ( “Power Integrations II ”). We noted that the “salient difference” between the '876 patent and Martin is Martin's inclusion of an erasable programmable read only memory (“EPROM”). Id. at 1366. We explained that Martin always includes an EPROM between the counter and the digital to analog converter and “does not teach removing the EPROM ... as in the '876 Patent.” Id. at 1367. We concluded, moreover, that “substantial evidence of objective considerations of non-obviousness [supported] the jury's conclusion that claim 1 of Power Integrations' '876 Patent would not have been obvious to the ordinarily skilled artisan.” Id. at 1369.

In December 2006, while district court proceedings were pending, the United States Patent and Trademark Office granted Fairchild's request for ex parte reexamination of claims 1, 17, 18, and 19 of the '876 patent. J.A. 165–73. The board affirmed the examiner's rejection of claim 1 as anticipated by Martin, as well as by two additional references: (1) Thomas G. Habetler & Deepakraj M. Divan, Acoustic Noise Reduction in Sinusoidal PWM Drives Using a Randomly Modulated Carrier, 6 IEEE Transactions on Power Elecs . 356–63 (1991) ( “Habetler”); and (2) Andrew C. Wang & Seth R. Sanders, Programmed Pulsewidth Modulated Waveforms for Electromagnetic Interference Mitigation in DC–DC Converters, 8 IEEE Transactions on Power Elecs . 596–605 (1993) (“Wang”). The board stated that Power Integrations “appear[ed] to argue that one of ordinary skill in the art would understand the term ‘coupled to’ to restrict device connections to exclude intervening components.” Power Integrations III, 2010 WL 5244756, at *4. The board concluded, however, that the term meant simply to “join[ ] devices into a single circuit,” and did not preclude the presence of intervening components. Id. In addition, the board rejected Power Integrations' argument “that the respective counters in Martin, Wang, and Habetler are not coupled to the respective digital to analog converters because all [Martin, Wang, and Habetler] disclose a [read only memory (“ROM”) ] separating a counter from a digital to analog converter.” Id. (citations and internal quotation marks omitted). In the board's view, Martin, Wang, and Habetler disclosed the limitations of claim 1 because they joined a counter and a digital to analog converter in a single circuit, and the counter “produce[d] a signal that causes a digital to analog converter to adjust control input by utilizing a corresponding memory, the counter (with the corresponding memory) being ‘coupled to’ the digital to analog converter.”Id.

The board also affirmed the examiner's rejection of claims 17, 18, and 19 as anticipated by Habetler. In light of its construction of the term “coupled to” in claim 1, the board rejected Power Integrations' argument that Habetler did not anticipate claims 17, 18, and 19 because it contains an EPROM between the counter and the digital to analog converter. Id. at *5. The board likewise rejected Power Integrations' argument that Habetler fails to disclose primary and secondary voltage sources. Id. at *6. According to the board, both the output from the digital to analog converter and the “average slope” of Habetler are voltage signals. Id. The board asserted that “Habetler discloses that [pulse width modulator (“PWM”) ] schemes utilize discrete tones in the voltage spectrum and that the output from PWM circuitry are waveforms with voltage amplitudes ... thus confirming that the PWM circuitry processes voltage waveforms to obtain output voltage waveforms.” Id. (citations and internal quotation marks omitted).

In February 2011, Power Integrations filed a request for rehearing with the board pursuant to 37 C.F.R. § 41.52. It argued that the board had “misapprehended” its argument regarding the proper construction of the term “coupled to” in claim 1 of the '876 patent, explaining that it had never contended that the term precluded the presence of intermediate circuit elements between the counter and the digital to analog converter. J.A. 935. Power Integrations further asserted that the board erred in finding that claims 17, 18, and 19 were anticipated by Habetler because that reference did not “disclose, teach or fairly suggest that the output of the [digital to analog] converter of FIG. 5 is a voltage, that the ‘average slope’ signal of FIG. 5 is a voltage, or that the input of the Triangle Generator of FIG. 5 is a voltage.” J.A. 952. Power Integrations argued, moreover, that the board had improperly shifted the burden of proof by applying a presumption that Habetler's average slope was a voltage. J.A. 951.

In May 2011, the board denied Power Integrations' request...