Taiwanese chip designer Richtek Technology said Wednesday it has filed a patent infringement complaint with the U.S. International Trade Commission (ITC) against several companies, including uPI Semiconductor, AMD, Sapphire Technology, Diamond Multimedia, and XFX.

Richtek claims the aforementioned graphic chip makers have infringed on three of the company's technology patents, as well as misusing business secrets. According to Fudzilla, the three patents deal with technologies for a Pulse Width Modulation (PWM) circuit, a method for current balance in a mulit-phase DC-to-DC converter to produce a respective PWM signal to regulate the corresponding channel current, and for a power metal oxide semiconductor transistor layout comprised of a gate electrode with a lattice pattern on a substrate having a first area and a second area.

Richtek is seeking an injunction and compensation, but the company didn't say for how much.