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One port to do it all: USB 3.0 in next-generation smart phones and tablets

Ayush Mittal, Cypress Semiconductor

April 03, 2013

Ayush Mittal, Cypress SemiconductorApril 03, 2013

Next-generation tablets and smartphones are set to replace not only laptops (see Tablet sales surging at PC's expense), but popular media players as well. They can replace DVD/Blu-Ray players by interfacing with the home-entertainment systems wirelessly, enabling users to enjoy multimedia while browsing the Internet on their tablets or receiving calls on their smartphones.

Just one "smart" device can talk with all the other devices around it, and with the tremendous processing power packed into them, they can eliminate the need for costly processing power in the other devices they are connected to. For example, by connecting a keyboard and LCD screen to a smartphone, you can now have the equivalent of a traditional PC up and functioning with an integrated 3G Internet connection. Connect high capacity USB flash memories smaller than a finger nail to a smartphone and you can remove the bulky media players from your living room because the phone will now drive your video/audio receivers. You won’t even need a separate remote control, like you did for your old media players.


Smart devices can be directly connected to HD photo and video cameras for data transfers. They can act like remote controls to such devices as a treadmill to collect your workout data; they can even 'smartly' control your workout regime. A tablet along with a smart phone can become your HD gaming console. Connect the tablet to HD-TV through wire, and multiple people can use their smartphones as wireless joysticks interacting with the tablet. Simply put, you can have one device to do it all.

Along with the huge processing power, another smart feature of these devices is how they interface with all the devices around them. Let us look at some key features we would expect a smart interface of a smart device to have.
  • High-speed communication: If devices need to transfer HD video/audio, they need to do so at multi Gbps rates. Note that this is uncompressed video/audio, given that there is no longer a separate media player in the loop.
  • Low power consumption: High-speed communication by itself is not enough. It is essential for these smart devices to save power while communicating, given their reliance upon a battery.
  • Universal language of communication: It is desirable that all devices speak the same language. This would save a lot of cost, power, and make things more convenient in general.
  • Physical compactness: An interface should not take a lot of area on the device.
  • Multi-purpose: It is highly desirable that the data interface could be used for all the purposes for which you would connect a wire to your mobile device, including battery charging.
  • Backward compatibility: Devices need to be able to talk effortlessly with their outdated predecessors.
  • Low cost: Cost is always a crucial consideration in the consumer electronics market.

In sum, we are looking for one port to serve all wired interfacing needs for mobile devices. Currently, several interfacing options like HDMI, USB 3.0, and DisplayPort are available. All current generation smartphones and tablets already have a USB 2.0 interface for data transfer; they use the same port for battery charging as well. USB has an installed user base of around 6 billion devices. On the other hand, HDMI and DisplayPort have gained popularity for home entertainment systems to carry uncompressed HD video/audio.

HDMI
HDMI has been in high-definition products since 2003. It has been the interface of choice to provide digital connectivity between HD media players, HD set-top boxes, and HD TVs. HDMI has gone through several revisions and in its latest version can support 3D video and 8-channel sound.

Along with 3D video, HDMI supports Audio Return Channel, a feature that allows the TV to return sound channels from the HD set-top box to a home theatre system. This eliminates the need for a separate audio connection from the set-top box to home-theatre system and hence the entire data transfer can be done using just two HDMI cables.

USB 3.0
To begin with, USB 3.0 was seen as an upgrade to USB 2.0 and its applications were considered to be primarily to improve the data transfer rates in all USB 2.0 applications. Also, USB 3.0 was introduced much later than HDMI, which had already become the preferred interface in HD entertainment systems. So far USB 3.0 has not considered as an interface for HD video transmission.

However, with SuperSpeed capable of data transfer rate of 5Gbps, USB 3.0 is able to transfer uncompressed full-HD video. In 2011, Point Grey (advanced camera makers) and AMD reported uncompressed 1080p/60fps video streaming over USB 3.0. Though USB 3.0 is still in a nascent stage not yet adopted universally as the preferred interface for HD video/audio transfer, USB 3.0 makes a strong case for itself for the following reasons:

The future of consumer electronics is being increasingly defined by smart mobile devices. These devices will replace existing set-top boxes by becoming the control center of everything electronic in the home.

All smart mobile devices will be upgrading to USB 3.0 sooner than later because it is compatible with USB 2.0 devices, supports higher battery charging rate, and has 10X the data transfer rates of USB 2.0.

Current generation TVs and media players that have USB 2.0 interfaces need a video decompressor to play media from USB memory devices. Next-generation TVs can eliminate the need for video decompression by using a USB 3.0 interface, leaving video decompression to a smart mobile device.

A faster USB 3.0 version is under development which will support data speeds up to 10Gbps. The only thing left to be done is to adopt USB 3.0 for HD video/audio transmission. Then it will be set to replace HDMI and all other ports that exist on present generation laptops, TVs, and other electronic devices. We will truly have one port that does it all.

Ayush Mittal graduated from the Indian Institute of Technology-Bombay in 2007 and has been working as an Analog Design Engineer (Staff) with Cypress Semiconductor Corporation. His current circuit design interests include high-speed I/O interfaces.

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