Consumers want to be able to go where they want, when they want. They want televisions to be seamlessly synchronized with tablets, phones, laptops, and automobiles. They want all their communication, information, and entertainment to be available immediately, with high resolution, all the time. Recently the automobile industry has caught on to this trend and has begun to show its vision of the future for the fully mobile lifestyle.
They also do not want to worry about running out of battery life – no more looking for an outlet at the airport. This untethered life is the Mobility Imperative and it is driving innovation in consumer products, which in turn, is pushing the limits of silicon-based semiconductor technology.
As silicon power transistors (MOSFETs) run out of gas, gallium nitride transistors are the next generation semiconductor devices in the world of power conversion and data transmission. Enhancement-mode gallium nitride transistors (eGaN[SUP]®[/SUP] FETs) from Efficient Power Conversion Corporation (EPC) have been in production for over five years. These devices are smaller in size, superior in performance, and lower in cost when compared with their aging silicon ancestor, the power MOSFET. GaN’s high-speed capability, coupled with lower production costs and smaller size, makes this technology ideal for accomplishing the Mobility Imperative.
Increasing Wireless Bandwidth – Increased Data Transmission, Increased Battery Life
Envelope tracking is a power supply technique for improving the energy efficiency of Radio Frequency Power Amplifiers by precisely tracking the power demand, as compared to today’s fixed-power systems. In cell phones use of envelope tracking means longer talk time, and in base stations it means smaller, less expensive amplifiers that consume far less energy and are less expensive to operate.
As our demand for wireless data grows, the value provided by envelope tracking increases dramatically. More transmitters alone cannot solve the problem; rather, more data transmission bandwidth per power amplifier is required. As the data transmission bandwidth increases, the efficiency of the transmitter’s power amplifier sharply declines unless the system adopts envelope-tracking methods.
Gallium nitride is being seen as an enabling technology for both envelope tracking converters and wide bandwidth RF Power Amplifier designs. The ultra-fast switching capabilities of eGaN FETs enable the high frequency, multi-phase buck converters used in envelope tracking power systems.
Figure 2: An example of an envelope tracking system using eGaN FETs. eGaN FETs are the tiny blue rectangles on the circuit board. (Photo courtesy of NewEdge Signal Solutions.)
Wireless Power Transfer Cuts the Cord…No Need to “find an outlet!”
Since Nikola Tesla first experimented with wireless power during the early years of the 20[SUP]th[/SUP] century, there has been a quest to “cut the cord” of electrical power – and go wireless! Now, more than 100 years later, the technological capability to achieve Telsa’s vision is a reality.
Highly resonant wireless power transfer, based on the generation of magnetic fields, has proven to be a viable path. Magnetic fields offer the necessary requisites for implementing wireless power – ease of use, robustness and, most importantly, it is considered safe. Applications for wireless power are endless, from charging cell phones and computers, to powering systems in hazardous environments and implantable medical devices.
With the explosion in the variety and number of mobile devices, wireless power transfer offers the convenience of charging batteries without the annoyance of cumbersome cables and the inconvenience of looking for outlets to “plug in.” Figure 3 is an illustration of what the home of the future might look like with all electrical appliances powered without power cords.
Over the past several years, three standards for wireless power transmission have emerged. These standards, put forth by industry consortia include the Wireless Power Consortium’s Qi, the Power Matters Alliance and the AirFuel Alliance standard, also known as Rezence[SUP]®[/SUP]. Only the technical approach embodied in the Rezence standard allows multiple gadgets to simultaneously charge from a single transmitter at a significant distance.
Figure 3: In the future electrical power cords may become obsolete as illustrated in this vision of the home of the future
The Rezence[SUP]®[/SUP] standard for wireless power transmission is about to see rapid adoption in mobile phone and tablet charging applications. For example, several automotive manufacturers are planning to embed wireless charging systems in the center console of their vehicles so the smartphone, as well as other mobile devices, can remain charged despite intense and continuous usage while the automobile is in operation. Given that the Rezence standard requires a high speed, 6.78 MHz, frequency for power transmission, eGaN FETs are the heavy favorite for adoption over the slower and less efficient silicon power MOSFET.
Figure 4: Wireless power transfer will be used in automobiles to keep smartphones charged despite continuous usage as part of the infotainment system. (Photo courtesy of Gill Electronics.)
Wireless charging for electric vehicles is also becoming more available as electrically powered cars become more prolific. Although there is no universal standard yet, loosely coupled magnetic energy transfer, similar to the method used in the Rezence standard, is common to all implementations. This is due to its ability to transfer power without precise alignment of transmitter and receiver units. eGaN FETs are certainly a good candidate technology for this application.
Automotive Sensing and Autonomous Control – Collision Avoidance or “Relax and Enjoy the Ride”
For safety reasons, it is critical that a car know what is around it at all times. This becomes even more essential as the car evolves into a self-driving machine. Further, the higher the speed of the vehicle and the more complex the surroundings, the faster the environmental sensing system needs to be, and the more precisely it needs to interpret the distance to a potential collision.
Today automotive manufacturers use a variety of sensors in these functions, including Light Distancing and Ranging (LiDAR) sensors that have only recently begun to emerge in automotive sensing autonomous driving applications.
Summary
In conclusion, a “Mobility Imperative” is upon us…the modern consumer is demanding that:
· they do not want the range anxiety caused by the worry about running out of battery life and having to “find an outlet.”
· all their information and entertainment be available all the time via their smartphone …all in high resolution and all “right now”
Gallium nitride is the fundamental technology bringing the “Mobile Imperative” to reality since it provides:
· increased switching speed leading to higher resolution and less power consumption.
· smaller size, thus enabling product miniaturization and weight reduction.
· low product costs, thus stretching the consumer dollar farther.
Consumers want to be able to go “mobile” wherever and whenever they want…this is today’s Mobile Imperative and it is driving innovation throughout consumer electronics.
The current semiconductor technology, silicon power transistors (MOSFETs), has reached its performance limits; fortunately, gallium nitride transistors with their high-speed capability coupled with lower production costs and smaller size, has come of age. It is GaN technology that will make Tesla’s vision come to fruition…and make it possible for us to achieve the Mobility Imperative.
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Next Generation of Systems Design at Siemens