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About USB Type-C

About USB Type C

USB Type-C™ is upon us, representing the most significant change to USB that most consumers will notice to date. On top of a new reversible connector, the maximum power has increased to 15W. Higher wattage makes it difficult to design power adapters that meet the required efficiency and standby power standards while maintaining the small form factor that customers expect. But it is not impossible, since new fly back controllers such as the UCC28704, which TI released earlier this year, further improve performance and include many advanced features for USB Type-C chargers.

USB Type-C is a USB specification for a small 24-pin reversible-plug connector for USB devices and USB cabling.[1]

The USB Type-C Specification 1.0 was published by the USB Implementers Forum (USB-IF) and was finalized in August 2014.[2] It was developed at roughly the same time as the USB 3.1 specification.

The USB Type-C connectors connect to both hosts and devices, replacing various Type-B and Type-A connectors and cables with a standard meant to be future-proof.[3][4] The 24-pin double-sided connector is similar in size to the micro-B connector, with a USB Type-C port measuring 8.4 millimetres (0.33 in) by 2.6 millimetres (0.10 in). The connector provides four power/ground pairs, two differential pairs for non-SuperSpeed data (though only one pair is populated in a USB Type-C cable), four pairs for high-speed data bus, two “sideband use” pins, and two configuration pins for cable orientation detection, dedicated biphase mark code (BMC) configuration data channel, and VCONN +5 V power for active cables.[5][6][7] Connecting an older device to a host with a USB Type-C receptacle requires a cable or adapter with a Type-A or Type-B plug or receptacle on one end and a USB Type-C plug on the other end. Legacy adapters with a USB Type-C receptacle are “not defined or allowed” by the specification, due to their being able to create “many invalid and potentially unsafe” cable combinations.[8]

All USB-C to USB-C cables are considered full-featured USB Type-C cables and must be active, electronically marked cables that contain a chip with an ID function based on the configuration channel and vendor-defined messages (VDMs) from the USB Power Delivery 2.0 specification. USB Type-C devices may optionally support bus power currents of 1.5 A and 3.0 A (at 5 V) in addition to baseline bus power provision; power sources can either advertise increased USB current through the configuration channel, or they can support the full power delivery specification using both BMC-coded configuration line and legacy BFSK-coded VBUS line.

Software support

Hardware support

An increasing number of motherboards, notebooks, tablet computers, smartphones, hard disk drives, USB hubs and other devices released from 2014 onwards feature Type-C receptacles.

Some non-compliant cables with a Type-C connector on one end and a legacy Standard-A plug or Micro-B receptacle on the other end incorrectly terminate the Configuration Channel (CC) with a 10kΩ pullup to VBUS instead of the specification mandated[28] 56kΩ pullup, causing a device connected to the cable to incorrectly determine the amount of power it is permitted to draw from the cable. Cables with this issue may not work properly with certain products, including Apple and Google products, and may even damage power sources such as chargers, hubs, or PC USB ports.[29][30]

remark: information from wikipedia