USB 3.0 INTRODUCTION

USB 3.0:

Universal Serial Bus 3.0 (USB 3.0) is a hardware communication interface used to connect peripheral devices to a computer. It is the third generation of the USB interface developed in 2008 and standardized by USB Implementers Forum (USB-IF).

The USB 3.0 interface provides a faster data transfer rate (DTR) than previous USB versions. USB 3.0 uses a dual-bus structural design, whereas earlier versions use a serial interface.

The USB 3.0 also replaces device polling (checking connections or determining the need to communicate) with an interrupt architecture protocol.USB 3.0 is also known as SuperSpeed USB.

A USB 3.0 device may be plugged into a USB socket and used as a USB power supply for direct current (DC) in connecting portable devices.

Compared to older USB versions, the USB 3.0 provides various features:

        1.Higher DTR of up to 5 Gbps
   
    2.Decreased power consumption
  
    3.Higher speed connectors and cables
   
    4.Backward compatible with USB 2.0
   
    5.Better power management structure
   
    6.Support of bulk and isochronous transfers
   
    7.Up to 80 percent more power with configured devices
   
    8.Up to 50 percent more power with non-configured devices
   
    9.Replaces device polling with interrupt architecture protocol
   
    10.Supports full-duplex data transfer using dual-bus architecture
   
    11.Supports a a power savings mode when idle (by either the computer or a device)

The USB 3.0 has 4-pin architecture, versus earlier versions. The USB 3.0 Type A plugs and sockets are backward compatible with USB 2.0, but USB 3.0 Type B plugs do not accept earlier socket versions.

The USB 3.0 was designed to increase power input, decrease power consumption and increase DTR speed. Currently, the USB 3.0 standard supports a DTR of up to 5 Gbps. Typically, the throughput is 4 Gbps, and the USB-IF considers a DTR of 3.2 Gbps attainable.

USB 3.0 have 8 primary conductors.Three usb twisted pair for USB data paths(D+,D-,SSTX+,SSTX-,SSRX+,SSRX-,GND,VBUS).

The power management of USB 3.0 is same as that of USB2.0 and Power distribution over the USB 3.0 deals with the issue of how USB devices consume power for downstream ports to which they are connected,It is similar to USB2.0 with increased suuply for device operating at super speed.

Earlier versions of USB used a device polling method, in which the host controller periodically looks for active data traffic. USB 3.0 replaced this method with an interrupt-based protocol, in which the devices “interrupt” the host by sending it a signal to begin data transfer.

This prevents any connected but non-active or idle devices (those not being charged by the USB port) from causing power drain by the host controller as it continually “polls” for data traffic.

Legacy 2.0 devices will benefit from this feature as well, as it is backward compatible with USB 2.0 certified devices.

Not only does USB 3.0 deliver a welcome increase in data transfer speed, it carries a heftier punch of power as well. USB 2.0 is unable to provide enough power for many devices, requiring these peripherals to use either two USB ports or their own power source in addition to the one USB connection.

USB 3.0 addresses this need with a substantial boost in its power output that will enable users to power and charge more devices, more quickly. This specification is often cited in general terms as an increase from USB 2.0’s 500 mA output to the 900 mA USB 3.0 specification.

This increase in current will also enable USB hubs to support more peripherals as well as allow even more power-hungry devices to charge via USB. so the most battery powered devices will also charge faster. 

USB 3.0 products and applications:

As the transition to USB 3.0 continues, many 2.0 devices will continue to be successfully deployed, taking advantage of the backward compatibility of the interface as the market moves toward mainstream adoption of USB 3.0.

Topping the list of applications best served by USB 3.0 are high-bandwidth devices that

currently challenge the throughput capabilities of USB 2.0, including:

    1.External hard drives (2–3 times faster than USB 2.0 predecessors)

    2.High-resolution webcams and video surveillance cameras

    3.Video display solutions

    4.Digital video cameras and digital still cameras

    5.Multi-channel audio interfaces

    6.External media such as Blu-ray drives

    7.High-end flash drives, particularly when multiple devices are attached via one USB hub