SAN FRANCISCO — IP litigator Matthew Powers has taken aim at Microsoft Corp., a company that counted him among its go-to defenders before he crossed over to plaintiffs work.

Represented by Powers’ firm, Tensegrity Law Group, IPLearn-Focus sued Microsoft in U.S. District Court for the Northern District of California on Friday for patent infringement. The Mountain View-based company claims that Microsoft’s Xbox products infringe three of its patents for aspects of systems with detached sensors. Microsoft did not respond to IPLearn-Focus’s offer to discuss a licensing partnership, according to the complaint.