Cirrus Logic Inc. et al. v. Greenthread, LLC

This Inter Partes Review (IPR) case, IPR2024-00019, involved petitioners Cirrus Logic Inc., Omnivision Technologies Inc., and AMS Sensors USA Inc. challenging a patent owned by Greenthread, LLC. The petitioners are all operating companies; Cirrus Logic is a fabless semiconductor supplier specializing in audio and mixed-signal integrated circuits for consumer electronics, OmniVision Technologies develops digital imaging products like CMOS image sensors for various applications including mobile phones and automotive systems, and AMS Sensors USA (part of ams OSRAM AG) is a global leader in light and sensor solutions for automotive, industrial, medical, and consumer electronics markets. Greenthread, LLC, conversely, operates as a non-practicing entity (NPE) or patent assertor, known for asserting semiconductor fabrication patents, particularly those originating from inventor G.R. Mohan Rao, against major technology companies. This assertion campaign is notably backed by a funder.

The patent at issue in this IPR was U.S. Patent No. 11,316,014. While the specific accused product is not directly litigated in an IPR, the patent belongs to a family of semiconductor patents asserted by Greenthread, generally relating to semiconductor devices with graded dopant regions for improved performance. Such technology would be relevant to the semiconductor components and imaging solutions produced by the petitioning operating companies.

The procedural posture for this case was an Inter Partes Review before the Patent Trial and Appeal Board (PTAB) of the U.S. Patent and Trademark Office. The petition was filed on October 27, 2023, and was subsequently terminated on April 18, 2024, due to a settlement between the parties. The PTAB serves as an important venue for challenging patent validity, often seen as a more efficient and less costly alternative to district court litigation for operating companies facing infringement assertions. This case is notable as it reflects a common strategy by operating companies to leverage IPRs to challenge patents asserted by NPEs like Greenthread, which has a history of litigating against various semiconductor and technology firms. The termination by settlement highlights a frequent resolution in such PTAB proceedings, often involving licensing agreements or other forms of dispute resolution.

Key Legal Developments and Outcome

This proceeding, IPR2024-00019, was a challenge to the validity of U.S. Patent No. 11,316,014 before the Patent Trial and Appeal Board (PTAB), not a district court infringement litigation. The key events are therefore specific to the IPR process and its interplay with parallel district court cases.

Chronological Developments:

• 2023-10-27: Petition for Inter Partes Review Filed. Cirrus Logic Inc., Omnivision Technologies Inc., and AMS Sensors USA Inc. jointly filed a petition for an Inter Partes Review against U.S. Patent No. 11,316,014, owned by Greenthread, LLC. The petition argued that claims of the '014 patent were unpatentable as obvious over prior art. This filing formally initiated IPR2024-00019.

• 2024-02-07: Patent Owner's Preliminary Response. Greenthread, LLC filed its Patent Owner's Preliminary Response, arguing against the institution of the IPR. This filing presented Greenthread's initial arguments as to why the petitioners had not established a reasonable likelihood of prevailing on their invalidity contentions.

• 2024-04-12: Joint Motion to Terminate. Before the PTAB could issue a decision on whether to institute the IPR, the parties jointly filed a motion to terminate the proceeding. The motion stated that the parties had reached a settlement agreement to resolve the dispute. Such pre-institution settlements are common and often arise from broader agreements that resolve parallel district court litigation.

• 2024-04-18: Termination of IPR. The PTAB granted the parties' joint motion and terminated the IPR proceeding. The case concluded without a decision on the merits of the patent's validity.

Parallel Litigation and Strategic Context:

The IPR was filed in response to district court litigation initiated by Greenthread. Greenthread had asserted the '014 patent, along with other related patents, against numerous technology companies in the Western District of Texas.

• Greenthread v. Cirrus Logic, Inc. (6:23-cv-00485, W.D. Tex.): This case was part of a broader assertion campaign. The filing of IPR2024-00019 was a direct strategic response by Cirrus Logic and its co-petitioners to challenge the validity of the asserted patent in a specialized forum known for its technical expertise.
• Motion to Stay: Typically, defendants in a district court case who file an IPR will also file a motion to stay the court proceedings pending the outcome of the PTAB review. While the specific docket for the Cirrus Logic district court case is not detailed in available public documents, this is a standard procedure. The rapid settlement and termination of the IPR before an institution decision suggest the stay motion (if filed) did not need to be decided.

The settlement that terminated the IPR likely encompassed a resolution of the corresponding district court litigation, which is a common outcome. The petitioners used the threat of a potential IPR institution to gain leverage and achieve a global settlement with the patent owner, Greenthread. Because the IPR was terminated prior to an institution decision, the PTAB made no findings regarding the patentability of the challenged claims in U.S. Patent No. 11,316,014.

Counsel for Petitioners

Based on the official filings in IPR2024-00019, the following counsel from Perkins Coie LLP represented the joint petitioners Cirrus Logic Inc., Omnivision Technologies Inc., and AMS Sensors USA Inc.

• David L. McCombs (Lead Counsel)

  • Firm: Perkins Coie LLP (Dallas, TX)
  • Noteable Experience: A nationally recognized intellectual property litigator and former chair of Perkins Coie's IP practice, McCombs has extensive experience leading major patent cases and PTAB trials, often representing large technology companies.

• Daniel R. Pote (Counsel)

  • Firm: Perkins Coie LLP (Dallas, TX)
  • Noteable Experience: Pote's practice focuses on complex patent litigation and post-grant proceedings, with a background in electrical engineering and computer science.

• Dr. J. Kory Park (Counsel)

  • Firm: Perkins Coie LLP (Dallas, TX)
  • Noteable Experience: Park is a registered patent attorney whose practice concentrates on patent litigation and PTAB proceedings, leveraging his Ph.D. in electrical engineering.

• Robert H. Reckers (Counsel)

  • Firm: Perkins Coie LLP (Denver, CO)
  • Noteable Experience: Reckers focuses on patent litigation and counseling, with particular experience in the semiconductor and electronics industries.

• Nathaniel E. Castellano (Counsel)

  • Firm: Perkins Coie LLP (San Diego, CA)
  • Noteable Experience: Castellano is an IP litigator who handles patent, trademark, and copyright disputes, including post-grant reviews before the PTAB.

Defendant Representatives

Based on filings with the Patent Trial and Appeal Board for IPR2024-00019, the following counsel from Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. appeared on behalf of patent owner Greenthread, LLC.

• James M. Wodarski (Lead Counsel)

  • Firm: Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (Boston, MA)
  • Notable Experience: Wodarski is a seasoned IP litigator with extensive experience leading cases before the PTAB, federal district courts, and the International Trade Commission (ITC).

• Andrew D. DeVoogd (Counsel)

  • Firm: Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (Boston, MA)
  • Notable Experience: DeVoogd's practice focuses on patent litigation in federal courts and post-grant proceedings, and he has represented clients in the semiconductor and electronics sectors.

• Daniel B. Weinger (Counsel)

  • Firm: Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (Boston, MA)
  • Notable Experience: Weinger is an experienced IP litigator who handles patent disputes across various technologies, including software and telecommunications, in district court and PTAB proceedings.

• Adam Rizk (Counsel)

  • Firm: Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. (Boston, MA)
  • Notable Experience: Rizk focuses on patent litigation and post-grant proceedings, leveraging his background in electrical and computer engineering for cases involving complex technologies.