Last month, Sony struck a deal with BT to turn the PlayStation Portable (PSP) gaming device into a phone by integrating VoIP. But it looks like the electronics giant has bigger plans for the popular gadget, by turning it into a cellphone.

An application, filed by Sony Ericsson in November, popped up on the US Patent and Trademark Office website last week.

The accompanying diagrams show a device that looks very much like a PSP with a rotating display, which is designed to be used as a mobile phone, TV or gaming console depending on the configuration.

In the application, Sony makes reference to the device as “a mobile information terminal” and mentions the unit’s “gaming function” and “TV or video function”.

Sony Ericsson has already seen great success from integrating its Japanese parent’s Cybershot and Walkman brands in its handsets, so it seems only natural to take advantage of the popular PlayStation brand.

The PSP has already shipped over 8 million units in Europe and 24 million globally, making it the second most popular handheld console behind Nintendo’s offerings.