Monolithic Power Systems has filed an antitrust and unfair competition claim against O2 Micro International in the U.S. District Court for the Eastern District of Texas. Monolithic alleges that O2 Micro has engaged in a scheme of procuring and attempting to enforce patents obtained by fraud on governmental patent offices and that O2 Micro is using the patents in an anti-competitive manner. The patents involved include Patent No. 6,804,129 and a related patent issued in Taiwan.

Monolithic Power Systems develops advanced analog and mixed-signal semiconductors. The company specializes in analog circuits with integrated high-performance power capability.