USB Power delivery will provide smart direct current power up to 100 watts

Most phones and other small gadgets can charge from a simple USB cable plugged into a computer or an adaptor. Some 10 billion of them are already in use. Hotel rooms, aircraft seats, cars and new buildings increasingly come with USB sockets as a standard electrical fitting. From 2014, a USB cable will be able to provide power to bigger electronic devices. In the long term this could change the way homes and offices use electricity, cutting costs and improving efficiency.

The big change next year will be a new USB PD (Power Delivery) standard, which brings much more flexibility and ten times as much oomph: up to 100 watts.

A prototype USB PD socket powers a laptop and LED office lighting, monitors, printers and desktops. Mains power is only for power-thirsty microwaves, kettles and the like.

A low-voltage DC network works well with solar panels. These produce DC power at variable times and in variable amounts. They are increasingly cheap, and can fit in windows or on roofs. Though solar power is tricky to feed into the AC mains grid, it is ideally suited to a low-voltage local DC network. When the sun is shining, it can help charge all your laptops, phones and other battery-powered devices.

USB carry direct current and also data. That means they can help set priorities between devices that are providing power and those that are consuming it: for example, a laptop that is charging a mobile phone. “The computer can say ‘I need to start the hard disk now, so no charging for the next ten seconds’,” says Mr Bhatt. The new standard, with variable voltage and greater power, enlarges the possibilities. So does another new feature: that power can flow in any direction.

Low-voltage DC power is cheap, safe and green. Big companies are working on rejigging chips and logic to fit the new standard. The first USB PD devices will come to market in 2014, with a “big roll-out” in 2015, says Brad Saunders of Intel. Gregory Reed, of the Swanson School of Engineering at the University of Pittsburgh, calls the new USB standard a “game-changer”. Big data centres, with their huge, humming arrays of servers, are already using DC circuits. Homes and offices will follow, he says.

The shift comes just in time for the “internet of things”—the idea that devices and gadgets can talk intelligently and automatically to each other online. That will mean many millions of new bits of equipment, all needing their own power supply and means of communication. The new USB standard provides both.

Mr Bhatt, who invented it 20 years ago, is delighted. His next plan is to make the USB cable “flippable”—so that the plug fits the socket whichever way it is inserted (for now it works only one way round). That tiresome flaw is because an original design priority was to make manufacture as cheap as possible: few believed his idea would really catch on.

SOURCE – Economist

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