Reading-based Dialog Semiconductor (www.dialog-semiconductor.com) , which supplies the power management chips used in iPhones, has bought a Californian chip-maker in a deal worth up to £234 million.

German-owned Dialog announced the acquisition of Silego Technology earlier this month, and said it could pay another £23 million in add-ons if the company meets certain targets.

Dialog relies on Apple for around three quarters of its revenue, and its shares tumbled earlier this year on rumours that the latter planned to design its own power chips.

Dialog dismissed the suggestion at the time, but its acquisition of Silego is expected to hasten its move into other areas such as the Internet of things and connected cars.

Silego, which has around 235 employees and is based in Santa Clara, designs microchips that combine multiple components in a small single unit — and its software allows chips to be designed in days, rather than months.

Its chips are used in devices from GoPro, Fitbit and Samsung; Apple is also believed to be a major customer.

Last month Imagination Technologies sold itself to Canyon Bridge Partners, a Chinese-backed fund, after its graphics chip designs were ditched by Apple.

In April, a German analyst suggested that the same could happen to Dialog after noticing staff from the company moving to Apple, sending its shares down by a third.