In Power Integrations, Inc. v. Fairchild Semiconductor Intl., Appeal Nos. 2015-1329, 2015-1388, the Federal Circuit held that induced infringement requires that the accused infringer actually induce a third-party direct infringer. Also, the Federal Circuit held that infringement under the doctrine of equivalents cannot stand where the finding vitiates a claim limitation.

Power Integrations and Fairchild asserted several patents against each other related to power supplies. In a bifurcated liability trial, the jury returned a mixed verdict on infringement and validity. The parties collectively raised twelve issues on appeal challenging, inter alia, induced infringement and claim vitiation under the doctrine of equivalents.

The Federal Circuit vacated the jury’s finding that Fairchild induced infringement. The jury instruction incorrectly stated that to prove induced infringement, direct infringement need not have been actually caused by Fairchild’s actions. Instead, the instructions explained that Fairchild only needed to encourage or assist infringement, regardless of whether that encouragement succeeded. The Federal Circuit held that the jury should have been instructed that Power Integrations had to prove that Fairchild successfully communicated with and induced a third-party direct infringer.

The Federal Circuit also reversed the jury’s finding that Power Integrations infringed a Fairchild patent under the doctrine of equivalents. The asserted claim required two distinct feedback signals. The jury found no literal infringement, meaning that the accused product had only one feedback signal. The Federal Circuit held that the jury’s infringement finding under the doctrine of equivalents vitiated the critical requirement that the second claimed feedback signal was “distinct” from the first feedback signal.