In Power Integrations, Inc. v. Semiconductor Components Industries, LLC, No. 2018-1607 (Fed. Cir. June 13, 2019), the Federal Circuit found an inter partes review (IPR) petition time-barred under 35 U.S.C. § 315(b).

Power Integrations owns U.S. Patent No. 6,212,079, related to switched mode power supplies. In November 2009, Power Integrations sued Fairchild Semiconductor Corporation for infringing the ’079 patent. In November 2015, while the trial was ongoing, Fairchild initiated a merger with Semiconductor Components Industries (“ON”). In March 2016, before that merger closed, ON filed an IPR petition challenging the claims of the ’079 patent. In September 2016, the Fairchild-ON merger closed. And four days later, the Board instituted ON’s petition.

Before the Board, Power Integrations argued ON was time-barred from filing its petition because (i) ON was in privity with Fairchild (undisputed time-barred party) when it filed its petition; and (ii) Fairchild became a real-party-in-interest (RPI) when the Fairchild-ON merger closed, four days before the Board instituted review of the ’079 patent. The Board rejected these arguments, and found ON’s petition was not time barred under § 315. The Board went on to hold the challenged claims unpatentable.

The Federal Circuit rejected the Board’s analysis and vacated and remanded. The Court held RPI and privity relationships that develop after filing but before institution can be assessed for purposes of the § 315 time bar. Because Fairchild was an RPI by the time of institution, ON’s petition was time barred.