Dan Dobberpuhl, founder and CEO of P.A. Semi, has left Apple to join several other former P.A. Semi employees at a new start-up. Citing multiple anonymous sources, Cnet reports that Dobberpuhl’s departure from Apple was not recent, and may have happened as early as fall 2009. “He was the CEO at PA Semi and leader of the team, and one of the guys that was driving the whole thing,” said Linley Gwennap, a chip analyst at the Linley Group. But “those guys are start-up kind of people, and within the structure of Apple, they may [have been] chafing.” According to the report, Dobberpuhl has joined other P.A. Semi engineers who have also left Apple at San Jose-based Agnilux, a start-up co-founded by former P.A. system architect Mark Hayter. Apple purchased P.A. Semi in April 2008, with plans of using the company’s expertise to build system-on-chips for iPhones and iPods.