NOT A GOOD TIME TO BE HYNIX: Rambus Inc., which is based in Los Altos, Calif., said Tuesday that it has sued Hynix and three other companies, alleging infringements of up to 18 of Rambus' patents relating to memory chips. The suit comes five days after Canadian firm Mosaid sued Hynix, alleging that Hynix was infringing on six of Mosaid's patents.

Rambus previously had filed suit against Hynix, claiming that Hynix was infringing on 15 of Rambus' patents. Last week, a federal judge found that Hynix was infringing on parts of four Rambus patents, Rambus said in a news release. The judge also granted Hynix' motion that nine claims relating to four patents be removed from the case. The first phase of the trial focusing on issues still in dispute is scheduled to begin March 21, Rambus said.