ARM on Thursday said that co-founder and President Tudor Brown will retire in May next year after helping turn the firm into a dominant mobile processor company.

ARM processors are found in most smartphones and tablets today, including Apple's iPhone and iPad. Brown worked at ARM since the company was founded 21 years ago, and became president in 2008 after filling roles that included chief technology officer and chief operating officer.

Brown joined the board of directors in 2001 and will not seek re-election, a company spokesman said.

ARM today is run by CEO Warren East, but Brown played a key role in creating customer relationships and promoting ARM's low-power chip architecture in mobile devices and embedded devices such as TVs and set-top boxes. ARM is battling Intel and MIPS in the smartphone, tablet, PC and server markets.

ARM licenses processor designs to chip makers such as Samsung and LG, which then use the chips in mobile devices. The company had 829 licensees as of Sept. 30, and billions of devices today use ARM processors. The company has said it aims to have ARM processors in 4 billion devices by 2015.