USB 3.0 and Power Delivery Highlighted

September 12. 2012, Intel Developers forum, San Francisco—We talked with Jeff Ravencraft of the USB-Implementers Forum about the state of USB. The organization is touting the growing acceptance of the 3.0 specification and the preliminary efforts in power delivery.

USB is becoming the default interface for more than just data. The interface can deliver up to 4.5 W of power to charge portable devices and is now required as the charging port for all portable devices in the EU and China. The Micro USB connector is now the standard for the common mobile charger.

USB 3.0 is moving towards rapid adoption by consumers and is changing from a storage mainly interface to a universal high-speed interface for many types of peripherals. The organization has doubled the number of certified products to about 600. Product volumes are growing from 500 M units last year to a projected 1 B this year.

Other changes to the base specification include a audio/video device class that supports A/V data, and a superspeed inter-chip configuration that eliminates the connectors for internal system data transfers at rates of up to 5 Gbps. This interface will use the MIPI Alliance M_PHY physical layer. Companies planning to use this interface will need to join the MIPI Alliance. The SuperSpeed USB Inter-Chip (SSIC) specification and the Mobile Broadband Interface Model (MBIM) specification extend USB applications for mobile devices.

One additional development is the IEC (International Electrotechnical Commission) and the USB Implementers Forum (USB-IF) announced IEC adoption of four USB-IF specifications for data transfer and charging. Those include the Hi-Speed USB (USB 2.0) specification, USB Cables & Connectors specification v2.0, USB Battery Charging specification v1.2, and Micro-USB Cables and Connectors specification v1.01.

Power delivery will depend upon source and sink profiles and the power spec calls for handshakes to set up the appropriate profiles. Power delivery can be in either direction to allow for greater flexibility and operating modes. The power delivery function will require detectable cables for currents greater than 1.5 A or voltages over 5 V. The new cables for power delivery will be certified and will bear a new mark to indicate power capabilities.

The new profiles default to a 10 W mode (2A @ 5 V in all modes) for hand-held devices and existing peripherals. This progresses to 18 W by adding a 1.5 A @ 12 V capability for tablets and other peripherals. Profile 3 goes to 36 W (3A @ 12 V) and 4 goes to 60 W (3A @ 20 V), limited by the Micro A/B connectors. The high power profile 5 can go to 100 W (5A @ 20 V), limited by the standard connectors.

More details and information are available at the organization’s website www.usb.org