Chip maker Rambus has filed another lawsuit against IBM, challenging a ruling made by the US Patent and Trademark Office (PTO).
The US Patent and Trademark Office had previously determined that IBM had not infringed on a Rambus patent.
According to news agency Reuters, Rambus has claimed that the US PTO had made an error in its judgement and maintains that an IBM application infringed on one of its patents.
The patent in question is related to a memory controller that is used to communicate with at least one memory subsystem.
Rambus, which draws a major chunk of revenue from patent licensing, said in its complaint: “The board committed errors of fact and law in its orders, decisions, and judgement.”
The company had earlier filed lawsuits against tech giants Samsung and Nvidia, ending with the two forming a licensing agreement with Rambus over memory controllers used in Nvidia chips. In this case, however, the ITC had determined that Nvidia had infringed on three Rambus patents.