USB 2.0 and 3.0 power specification announced

The organizations behind the USB specification, the USB 2.0 and 3.0 Promoter Groups, have completed an extension of the specification. According to the USB Power Delivery Specification, USB ports must be able to deliver 100W of power.

The original USB specification provided for a lower power for connected devices than is now used by some manufacturers. With a voltage of five volts and a current of 500 to 900 milliamps, powers of 2.5 to 4.5W were delivered, but charging ports up to 1.5A, or 7.5W, and even 5A or 25W are possible. The new specification aims to increase that further to 100W, which involves both a higher current and a higher voltage.

To the specification extension, the USB Power Delivery specification, included companies such as Intel, Dell, HP, Nokia, Renesas and Texas Instruments. Ports should operate in different profiles, with 5, 12 or 20V, allowing currents of 1.5, 2, 3 and 5A. The latter profile delivers 100W, enough to power an external monitor with a laptop or to power an external hard drive without a separate power adapter.

However, the specification provides for a bi-directional exchange of energy. For example, a laptop could also be charged via the USB cable that runs to a monitor, provided the monitor is connected to the mains. The fast charging of tablets or smartphones is also standardized with the USB PD. The profiles are automatically negotiated and should work with the latest USB 3.0 version as well as older USB standards.