A Taiwanese semiconductor design company has complained to the US International Trade Commission (ITC) that AMD and others have breached a patent it owns relating to graphics cards.
Taiwanese wire Digitimes said that Richtek filed the complaint against AMD, uPI Semiconductor, Sapphire Technology, Diamond Multimedia and XFX Technology.
One of the patents, US patent number 7,315,190 is for a PWM circuit and a PWM integrated circuit, a patent granted to Richtek Technology Corp from Hsinchu, Taiwan, on the 16 of June 2006.
An earlier patent, US 6,414,470 relates to an apparatus and method for balancing channel currents in a multiphase DC-to-DC convertor - granted on January 22, 2002.
The last patent it's alleging has been breached was granted on April 20, 2005 and describes a power metal oxide semiconductor transistor layut with lower output resistance and high current limit.
Digitimes also reports that Richtek has filed suit against the defendants in a California district court.