David A. Prange



When key business and legal decisions demand clear answers, trial lawyer and licensed patent attorney David Prange provides the definitive advice clients need. Pragmatic, technical, and analytic, David uses his training as a scientist and knowledge of competitive-advantage litigation to help clients navigate their complex intellectual property problems. Clients first appreciate David because of his nuanced, experienced-based understanding of litigation. They then come to rely on his leadership abilities, integrity, and ability to translate sophisticated technologies into relevant legal cases, claims,defenses, and theories.

Practice and Technologies

David’ s experience litigating disputes involves patent infringement, trade secret misappropriation, and trademark infringement, as well as insurance coverage and contractual licensing relating to intellectual property assets such as patents, standard-essential patents, and trade secrets. David’s cases have covered a wide a range of technologies: the hardware and software of personal electronics; communication protocols (wired and wireless) and sensor technologies; aircraft navigation, fail-safe, and GPS systems; aircraft flame barrier laminates; irrigation controllers and sensor integration; mechanical vehicle transmissions; consumer and commercial water purification and remediation systems; battery technology; and medical devices.

David has appeared in federal district courts across the country, the ITC, and has further prosecuted appeals in state and federal appellate courts. David is experienced in all phases of litigation, including pre-suit investigations; discovery and implementing cost-containment strategies for source code and electronic discovery; development and implementation of technical and financial expert opinion testimony; depositions; non-dispositive and dispositive motion practice; claim construction practice; pre-trial and trial practice; appeals; and settlement negotiations.

David is licensed before the United States Patent and Trademark Office as a patent attorney.

Giving Back

David volunteers in the community by offering pro bono legal and nonprofit board volunteer services. His pro bono representations include efforts to protect at-risk children by representing a court-appointed guardian ad litem as well as successfully representing a regional historical society in a board of directors control dispute to ensure its ongoing viability. He also serves on the board of the Edina Soccer Club.



Trial counsel for plaintiff TQ Delta in TQ Delta, LLC v. 2Wire, Inc. involving patents addressing memory sharing for data packet transmission used by Digital Subscriber Line (DSL) modems. Venued in the District of Delaware. At trial, a jury found defendant 2Wire infringement three TQ Delta patents. Responsible for the direct and cross-examination of expert witnesses regarding the operation of accused devices using Broadcom semiconductor chips, as well as cross-examination of third-party Broadcom appearing on behalf of 2Wire.

Trial counsel for defendant Unifrax in E.I. du Pont De Nemours & Co. v. Unifrax I LLC involving a patent addressing flame barrier laminates used in commercial aircraft. Venued in the District of Delaware. At trial successfully defeated a claim for lost profit damages in a controlled two-supplier market. Responsible for case strategy, day-to-day case management, trial witness presentation and cross-examination for lay and expert witnesses, and lead defense of damages claims.

Trial counsel in Personal Audio LLC v. Apple Inc., a patent infringement case in which a Texas federal jury awarded our client, Personal Audio LLC, $8 million in damages for infringing a patent for an audio player that can download or receive navigable playlists. The jury found that Apple's iPods infringed the patent. The court also awarded prejudgment interest in the amount of $4,182,331 for a total judgment of $12,182,331.

Trial counsel for Petitioner in The Toro Company v. MTD Products Co., IPR No. 2016-00194 challenging U.S. Patent No. 8,011,458 directed to mechanical transmission linkages for zero-turn-radius vehicles. Successfully invalidated all challenged claims at the PTAB; appeal pending at the Federal Circuit.

Trial counsel for Petitioner in The Toro Company v. MTD Products Co., IPR No. 2016-00219 challenging U.S. Patent No. 8,136,613 directed to mechanical transmission linkages for zero turn radius vehicles. Successfully invalidated all challenged claims at the PTAB; PTAB decision affirmed on appeal.

Counsel for defendant Toro in MTD Products Co. v. The Toro Company in a business competitor suit involving three mechanical transmission linkage patents for zero-turn-radius vehicles. Venued in the Northern District of Ohio. Lead case strategy and day-to-day case management and development. Invalidated two patents via IPR and challenged venue, achieving withdrawal of preliminary injunction motion based on third patent written in view of the accused product. Following withdrawal of the preliminary injunction motion, the case resolved on confidential terms.

Counsel for defendant Sensus USA in Badger Meter, Inc. v. Sensus USA, Inc. involving a patent addressing flow control metering technology for fluid distribution. Multiple actions venued in the Eastern District of Wisconsin and Northern District of California. Responsible for strategy development and all aspects of day-to-day case management and claim and defense development. The case resolved between competitors on confidential terms following cross-motions challenging venue and personal jurisdiction. 

Counsel for defendant Sensus USA in GroupChatter LLC v. Sensus USA, Inc. involving patents addressing wireless communication protocols for utility metering. Venued in the Eastern District of Texas. Responsible for strategy development and all aspects of day-to-day case management and claim and defense development, and management of joint defense group. The case resolved on confidential terms following 35 U.S.C. § 101 patent eligibility and venue challenges.

Represented a patent owner in four inter partes review proceedings filed on one patent involving lithium battery separator technology.

Counsel for plaintiff in Honeywell International, Inc. v. Furuno Electric Co., Ltd, Navico, Inc., and Raymarine PLC involving patents addressing GPS navigation and control, and navigation displays for commercial aircraft and other vehicles. Venued in the District of Minnesota. Responsible for strategy development and all aspects of day-to-day case management and claim and defense development.  The dispute against each defendant resolved on confidential terms.

Represented Honeywell International Inc. in In re Certain Navigation Products, Components Thereof, and Related Software in the Internal Trade Commission. Defended Honeywell on claims of patent infringement relating to aeronautical display systems against Furuno Electric Co. Dispute resolved in settlement.

Represented multiple defendants in a federal patent infringement action involving consumer refrigerator replacement water filters. Resolved in settlement following fact discovery. (Prior to joining Robins Kaplan LLP)

Represented multiple defendants in a federal patent infringement, trade secret misappropriation, and false advertising action involving soil monitoring and wireless communication technology.  Resolved in mediated settlement following Markman ruling and completion of fact discovery. (Prior to joining Robins Kaplan LLP)

Counsel for multiple clients involved in the licensing and assertion of standard essential patents involving standards 3G, 4G, LTE, ADSL2/ADSL2+, VDSL, H.264, HEVC, and VP9 for wireless handsets, infrastructure transmission, DSL, video encoding/decoding, and other related technologies.

Trade Secret:

Counsel representing Honeywell International Inc. in a trade secret and breach of contract dispute with Ophir Corporation involving Lidar-based optical air data systems for navigating aircraft.  Settled the case on behalf of Honeywell  after previously prevailing on a motion for a temporary restraining order/preliminary injunction.  The dispute was venued in the United States District Court for the District of Arizona as Case No. CV-17-02083-PHX-GMS.

Lead counsel for defendant Medtronic in Thompson et al. v. Medtronic, Inc. et al. involving patent inventorship and unjust enrichment claims, and allegations of trade secret misappropriation. Venued in the Western District of Tennessee. Coordinated joint defense group and successfully dismissed all claims on motion practice before commencement of discovery following removal to federal court and assertion of preemption of common law claims by the Tennessee Uniform Trade Secret Act.

Represented multiple defendants in a federal patent infringement, trade secret, and false advertising lawsuit involving soil monitoring and wireless communication technology. Resolved in mediated settlement following Markman ruling and completion of fact and expert discovery. (Prior to joining Robins Kaplan LLP)


Represented an international association in a federal trademark infringement lawsuit involving the trademark NEUROLOGY and corresponding publication.  Resolved as part of related business agreement. (Prior to joining Robins Kaplan LLP)

Trial counsel in a trademark application opposition regarding the trademark BRAIN MATTERS before the Trademark Trial and Appeal Board.  Resolved during testimony phase of opposition proceeding.  (Prior to joining Robins Kaplan LLP)

Represented owner of the trademark COCO BUTTER FORMULA in federal trademark infringement lawsuit. (Prior to joining Robins Kaplan LLP)

Pro Bono: 

Lead trial counsel for the Guardian ad Litem of a child in In re A.M.C. Following a three-day trial a district court granted the Guardian’s petition to terminate the parental rights of the parents’ and place the child up for adoption. Decision affirmed on appeal.

Lead counsel for defendant in Clarey v. Krishnaswamy, a defamation action based on internet postings.  Obtained dismissal with prejudice.  Case recognized as a 2007 "Lawsuits of the Year," by Minnesota Law & Politics.  (Prior to joining Robins Kaplan LLP)

Lead counsel for officers and directors and a nonprofit in a series of cases involving corporate control and contractual claims for attorney fees indemnification.  Resolved declaratory relief claims related to corporate control in favor of officers and director clients, and defeated subsequent claim for attorney fees on summary judgment resulting in no loss to the society or individual directors and officers.  (Prior to joining Robins Kaplan LLP)

  • Named a "Minnesota Rising Star," Super Lawyers (2011-2015)
  • ABA Military Pro Bono Project Outstanding Services Award (2018)
  • Edina Soccer Club, Board Member
  • Northwest Suburban Chapter of Pheasants Forever, Board Member
Bar Admissions
  • Minnesota
  • U.S. Court of Appeals, Federal Circuit
  • U.S. Court of Appeals, Third Circuit
  • U.S. District Court, Eastern District of Texas
  • U.S. District Court, Minnesota
  • U.S. Patent and Trademark Office
  • U.S. Supreme Court
  • University of Nebraska - Lincoln College of Law, J.D., with High Distinction, Order of the Coif  
  • Saint Olaf College, B.A. in Biology, magna cum laude and Phi Beta Kappa       
Professional Associations
  • American Intellectual Property Law Association
  • Federal Bar Association
  • Recent Developments in Patent Litigation Damages
    Boston Patent Law Association Licensing and Litigation Committees Joint Event: Symposium on Patent Licensing and Damages, Boston, Massachusetts (November 19, 2019) 
  • A Starting Point for Standard Essential Patents
    Minnesota CLE Seminar (March 22, 2019)
  • The US Jury Trial and the Role of Juries in Resolving IP Technology Disputes
    HSML China Symposium (August 3, 2018)
  • The Protection of Trade Secrets Under US Law
    HSML China Symposium (August 1, 2018)
  • Panel on Best Practices in Trade Secret Litigation
    Federal Bar Association, Minnesota Chapter, Minneapolis, Minnesota (April 17, 2018)
  • Protecting Digital Property Innovation
    Webinar, Minnesota CLE (October 9, 2017)
  • With Millions of Dollars at Stake
    Licensing Executives Society, Seattle, Washington (September 20, 2017)
  • Well Kept Secrets A Panel Discussion about the Defend Trade Secrets Act
    Federal Bar Association, Intellectual Property Section, Minneapolis, Minnesota (May 25, 2017)
  • Facebook and Ubers Billion Dollar Headache
    Panelist, Intellectual Property Magazine, Webinar (April 27, 2017)
  • Litigating Trade Secret Cases: Early Strategic Considerations
    Mitchell Hamline School of Law, St. Paul, Minnesota (April 21, 2017)
  • Protecting Innovation in a Digital World
    Palo Alto, California (March 21, 2017)
  • Compiling Strategies for Protecting IP in Software
    PRG Conference, Orlando, Florida (April 12, 2015)
  • Inter Partes Review and Life Sciences: How Your Patent Could Be Killed In About a Year
    MedTech Investing Conference, Minneapolis, Minnesota (May 21, 2014)
  • Introduction to Patent Law - A Practical Perspective
    Federal Bar Association, Minnesota Chapter, Judicial Law Clerk Patent Law Training, Minneapolis, Minnesota (October 13, 2011)
  • Trademark Surveys: How to Use Them…Wisely
    Intellectual Property Institute, with Ernest W. Grumbles, III (September 28, 2007)


Links to full publications and news releases.
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