The Wisconsin Alumni Research Foundation alleges that Apple's A7 processor, which is used in its iPhone 5S and other devices, incorporates technology patented by the university in 1998. It was developed by four UW-Madison computer microprocessor architecture researchers.
It's not the first time the nonprofit foundation has sued over the same patent, the Wisconsin State Journal reported Wednesday. It sued Intel for infringement and that lawsuit resulted in a 2009 settlement, terms of which are confidential.
Apple did not immediately respond to a Wednesday phone messages from The Associated Press seeking comment.
In addition to the iPhone 5S, the technology is used in the iPad Air, and the iPad Mini with Retina Display.
The lawsuit, which was filed Monday in U.S. District Court in Madison, asks the court to rule that the patent is valid and was willfully infringed and seeks to bar Apple from further infringement. It also seeks unspecified monetary damages and fees.
WARF general counsel Michael Falk said the so-called 752 patent "has been recognized in the field as a major milestone in computer microprocessing." He said the technology "significantly enhances the performance of a microprocessor, among other benefits."
Usually, in cases such as this, the company filing the lawsuit is not looking to stop production of the products that claim to violate the patent but to get money, said Madison attorney John Scheller, a partner with the law firm Michael Best & Friedrich.
"I think it's interesting in that WARF, historically, has not been very litigious. So they must feel they have some rights here that need to be enforced," Scheller said. An online check showed WARF has filed three other patent infringement lawsuits in U.S. District Court in Madison since December 2012.