DesignWare Technical Bulletin

SuperSpeed USB 3.0 Rises in Smartphones

As consumers carry more mobile devices with increasing amounts of memory and features, they will transition from basic phones to smartphones and from smartphones to even smarter phones. Consumers are recording more videos, downloading more music and taking more pictures, so the demand will increase for devices capable of fast data transfer, sufficient memory capacity and long battery life. To address this demand, device manufacturers will transition from USB 2.0 to USB 3.0 to save power, improve performance and add functionality so consumers can carry their media, music, video camera, digital camera, and tablet everywhere, anytime.

The Need

Smartphones will continue to grow in market share as service providers push smartphones to generate additional revenues from data packages, while consumers continue to pull on the demand side by requesting more features and higher data speeds. A great example of this is the latest iPhone 4S. iPhone 4S users take eight megapixel pictures and record 1080p video. To store this digital content, the iPhone 4S contains up to 64 GB of memory. Future phones will contain 64 GB to 128 GB of memory or more. Users will fill the memory with videos of soccer games, spring break, birthday parties, or, let's face it, actions that should not ever be recorded or broadcasted (like spring break). Pictures and video will be stored on USB 3.0 hard drives for posterity, but only after being transferred to a PC first. Will LTE, 3G phone networks and the Cloud be sufficient for moving these memories quickly and storing them forever? It's unlikely. The amount of data created will be larger than the data capacities of LTE or 3G networks (like when AT&T's networks slowed down with the success of the first iPhones). The cost of storing data infinitely on the Cloud will remain high.

Users will need and want to upload their content to PCs or a central storage device for safekeeping. They will want to download their personally created or purchased commercial digital movies and content on to smartphones. If you own an iPhone today or ever have upgraded from one iPhone to another, you know exactly how many hours it takes to move your media across. The speed of USB 2.0 isn't going to be fast enough. The table below shows the relative speed and complexity of the various generations of USB specifications.

The Future

In the future, smartphones will have a USB 3.0 device port acting as a peripheral to sync with your laptop. This provides the speed needed to transfer large amounts of data and also reduces the power required. Why? The USB 3.0 transfers require about 2x the power, but provide 10x the speed. This means that you can transfer 10 GBs of data in 1/10th the time using USB 3.0 but consuming only 20% of the power of USB 2.0. Also, once the transfer has completed, the USB 3.0 stops transmitting. The "passive" power consumption is lower, allowing the battery to last longer. Even if the battery is charging from a host at the time, the system runs cooler, allowing CPU cycles, bus cycles or interrupts to be available for other functions. Those cycles enable greater functionality while USB 3.0 operates, so USB doesn't consume the processing power from other on-chip functions.

USB 3.0 and the Cloud

It certainly seems like the Cloud should be a convenient, trusted entity for everyone to store their most precious memories. But the cost of a 1 TB USB 3.0 hard drive today is less than $100 and 1 TB of memory will store a lifetime of pictures and videos. Also, for the moment, the Cloud restricts the user to a single service or set of devices and would cost $1000's of dollars per year to store that amount of data. It seems likely for mainstream users that a USB 3.0 hard drive or a portable, external drive will continue to be the backup method of choice for digital media and data.

One USB Port, Two Capabilities

Similar to how USB 2.0-based phones work today, USB 3.0-based smartphones will be used as a USB 3.0 peripheral the majority of the time. However, internally, USB 3.0-based smartphones will contain a USB 3.0 dual role device connection. This means that a single port can act as either a peripheral (device) port or a host port. Because the USB 3.0-based smartphones of the future will be so capable, users will start to use the phone as a laptop substitute. Users can plug it into a USB 3.0 docking station that includes a USB monitor, keyboard, and mouse. A good illustration of this concept in USB 2.0 today is the Motorola LapDock shown below.

The device will charge the phone while the user works on e-mails and presentations on the phone. The docking station is actually a USB 3.0 peripheral, which means the phone acts as a host. As a USB 3.0 host, the phone connects and manages the input and output to the monitor from the USB keyboard and mouse. USB 3.0 makes this more compelling by offering faster data rates to enable high-resolution video streaming. USB 3.0 video in these designs will be supported by chips from companies like DisplayLink, which transfer video data from USB 3.0 to HDMI. For a demonstration of the DisplayLink product visit the To USB or Not to USB Blog.

USB 3.0-Based Smartphones

USB 3.0 provides faster performance with lower power consumption for mobile devices by reducing the overall loading on the CPU and on-chip bus. This leaves additional power, CPU cycles, and bus bandwidth to support high performance features like graphics processing, while maintaining improved battery life. Today, the availability of USB 3.0 dual role device IP controllers and PHYs gives system makers more options for integrating features and add-on products that provide consumers increased value from their smartphones. With the availability of USB 3.0-based smartphones, the entire ecosystem of adjacent USB 3.0 market segments will be positively impacted including tablet PCs, personal computers, digital storage, TV's, set-top boxes, and digital still and video cameras. To be ready for this next generation of "SuperSpeed" USB capable smartphones, new products must support USB 3.0. Product makers should ask themselves if they are "Ready for USB 3.0?"

More information on the DesignWare SuperSpeed USB 3.0 IP solution.

For the latest trends and topics in USB IP, visit the "To USB or Not to USB" Blog

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