The booming iPod economy continues to drive profits for Apple's partners.

Scottish electronics firm Wolfson Microelectronics will this week reveal that booming sales of iPods and PSPs have doubled the company's profits.

The Scotsman reports that shares stand at 417.25p - close to 100 per cent growth since the company first floated on the stock exchange in 2003.

The Edinburgh microchip designer is expected to reveal pre-tax profits of more than £17m for 2005, up from £8.5m the year before.

Wolfson chips can also be found in the Xbox and car navigation systems such as TomTom.