Earlier this month the USB Implementers Forum announced the new USB Power Delivery 2.0 specification. The specification defined new standards for power delivery to allow Type-C USB ports to supply devices with much greater amounts of power than the previous standard allowed, now up to 5A at 5V, 12V, and 20V, for a maximum power delivery of 100W.
VESA utilized the Alternate Mode functional extension of the USB Type-C specification in the development of this new Standard. The DisplayPort Alt Mode repurposes some or all of the four existing SuperSpeed USB lanes to deliver full DisplayPort performance, and uses other signaling available in the USB Type-C connector for DisplayPort's AUX channel and HPD (Hot Plug Detection) function. This enables computers, tablets, smartphones, displays, and docking stations to implement the new USB Type-C connector at both ends while using the DisplayPort Standard over USB Type-C to transmit high-resolution A/V along with USB data and power.
Devices supporting DisplayPort Alt Mode on a USB Type-C connector can also connect to an existing DisplayPort device using a reversible USB Type-C to DisplayPort converter cable. Video source devices that support DisplayPort Alt Mode on a USB Type-C connector can use an appropriate adaptor to drive an HDMI, DVI or VGA display. All adaptors and converter cables will comply with all USB Type-C characteristics, including reversible plug orientation and cable direction.
Like USB, DisplayPort uses a packetized data structure and differential AC-Coupled signal "lanes" that carry high speed data with an embedded clock. This allows the same electrical circuits and cables to carry either SuperSpeed USB data, at up to 10 Gbps per lane, or DisplayPort, at up to 8.1 Gbps per lane, as defined in the new DisplayPort 1.3 Standard. Early implementations of DisplayPort Alt Mode USB Type-C devices will likely use existing DisplayPort 1.2a capabilities that support up to 5.4 Gbps per lane. Using 5.4 Gbps across all four high-speed lanes will support up to 4K (4096 x 2160) display resolutions at a 60Hz frame rate with up to 30-bit color.
By leveraging USB Type-C's flexibility, the DisplayPort Alt Mode can choose to transmit on just one or two of the four available lanes, so that the other two lanes can be used for SuperSpeed USB data at the same time. In a docking station connection, for example, the use of two lanes for DisplayPort at 8.1 Gbps per lane would allow simultaneous transfer of SuperSpeed USB data (up to 10 Gbps in each direction) while also supporting a 4K UHD (3840 x 2160) DisplayPort monitor. The dock can also be configured with DisplayPort protocol converters to support HDMI, VGA and/or DVI monitors. When using all four lanes for DisplayPort Alt Mode, which could drive a monitor with up to 5K (5120 x 2880) resolution, USB 2.0 data can still be carried across the USB Type-C connection using separate pins dedicated for that function.
The VESA is expecting the first DP Alt Mode capable devices to appear in 2015, which is the same year Type-C ports begin appearing on devices as well.