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Outlook 2015: Meeting the challenges of efficiently powering the future

If you're like me, there is a moment of panic when your evening is interrupted abruptly as the power goes out. You may have to wait to warm something to eat and you'll have to find some candles or a torch. You can't get your car out of the garage because the electric door opener doesn't work and when was the last time you tried opening it manually?

But then you reach for your phone or tablet. Thankfully, you charged it earlier, so you can still get a news update, watch your favourite television show or get some work done. The experience serves to remind us how dependent we are on the modern convenience of power in our daily lives.

I would argue that power efficiency has been the most pressing and universal design challenge for the last decade and that pressure in this area of system design is only increasing. We all know the reasons why: we are trying to reduce our energy demands, while looking for 'greener' approaches to many of our most power hungry applications.

This is driving regulation that impacts consumer, industrial and automotive electronics. We are incredibly reliant upon mobile technologies for communication, data aggregation and entertainment and these technologies have more functionality in a smaller and thinner footprint. This constrains the size of the battery and requires further innovation to enable us to keep these mobile devices unplugged. The infrastructure being built to support the massive increase in data transmission and storage is itself a big energy drain, costing more to cool than the equipment itself. And the Internet of Things – the beginning of interconnecting nodes in homes and factories to add intelligence to how we live and work – is totally reliant upon the ability to make those connected nodes run off of a battery; not for hours or days, but for years.

At Intersil, we're focused on a couple of key areas where silicon providers can innovate to make a difference in power efficiency. Some of the most innovative efficiency IC technology originated in the PC market, where the rapid increase in processing power created a need for better power management. Multi-phase controllers emerged that use modulation techniques to divide the current and share it across converters, reducing board space and reducing the number of capacitors and inductors required to absorb energy. These converters had to be able to share current accurately under all operating conditions. This challenge, if not handled correctly, can cause reliability issues, unpredictable performance and even system failure. But as multi-phase modulation techniques improved, devices have been able to reach the target voltage faster, reduce the capacitance (energy loss) and improve efficiency dramatically in a smaller footprint.

Interestingly, as PCs have morphed into laptops and now ultrabooks, and cell phones have evolved into smartphones, and tablets have emerged as a category bridging the two, the need for multi-phase modulation has resurfaced. The increased processing requirements for these mobile platforms, combined with space-constrained form factors, made the efficiency gains just as critical. This time, preserving or extending battery life is the key driver.

Market research firm IDC completed a survey of consumers emphasising that 56% of Android buyers, 49% of iPhone buyers and 53% of Windows Phone buyers said battery life was a key reason they bought their particular device. In fact, battery life ranked highest of all of the factors impacting their smartphone purchase decision.

So while battery life is a determining factor, there are a number of things working against battery conservation in mobile devices. The first is new display technologies: while they offer higher resolution, these beautiful new displays and backlight LEDs consume the majority of the battery power when used for web browsing and emails.

Hand-in-hand with innovation in display technology, new IC technologies are entering the market to provide a power efficiency solution. Creative integration of functions, such as the ISL98611's display power and the backlight LED driver, in a single IC solution, is enabling meaningful battery savings. Improving power efficiency from 85% to more than 90% translates into up to another hour of battery life. The integration of these functions provides energy savings, while improving display brightness and uniformity, adding features like hybrid dimming to eliminate white LED colour shift issues at low LED current, which occur with DC dimming.

The display is not the only culprit, of course: new features, including fast charging and quick start also create power management opportunities. Push notifications, a proliferation of radio technologies and the reliance on and availability of more applications are also draining the battery. Whilst improvement in the batteries themselves is likely to appear over the next three years or so, it is the ability of IC vendors to target even small efficiency gains in the most critical elements of the system that will have big returns.

Mobile devices are not the only power pain point. In the process of building large data centres and other infrastructure to support voice, video and data storage/transmission, high power conversion efficiency is needed to reduce electricity usage and heat dissipation.

Electricity consumption of data servers, for example, is rising exponentially. A report on this topic, published when data centres were far less prevalent than they are today, showed that aggregate electricity usage in data centres worldwide doubled to 140billion kWh/yr from 2000 to 2005. From 2005 to 2010, electricity usage increased again by more than 50%, with efficiency improvements already starting to have an impact on the growth rate. Electricity used for equipment, cooling and power distribution in data centres represented an estimated 1.3% of total world electricity consumption in 2010.

In addition, these systems continue to be built for higher and higher power density. Just as we've seen in mobile computing, we are also seeing servers and other infrastructure equipment with increased processing power and deep sub-micron process technology that is creating power conversion challenges, which are making efficiency gains challenging. Voltages scale lower and currents scale higher as the process nodes shrink for the processors, FPGAs, ASICs and memory used in these advanced systems. This increased processing power drives lower voltages with tighter tolerances.

But even a 1% gain in these environments accounts for meaningful savings. As a result, much has been done to innovate in power management to squeeze out every bit of efficiency that is possible within the system. Advanced DC/DC converter technology has been developed to improve load transient performance. Here, we also see the benefits of multi-phase modulation providing the intelligence to deliver efficiency gains.

I've only touched on a few obvious applications where the costs of power inefficiency are easy to quantify. There are many more applications where the value of improved efficiency is just as obvious. In the case of the Internet of Things, power efficiency is a key requirement for widespread adoption because embedded sensors, for example, must operate without a battery change, in some cases for decades. There is also white goods where consumer sensitivity to electricity usage drives purchase decisions and, of course, automobiles, where hybrid and electric vehicles are driving new innovations in battery and power management technologies.

From Intersil's perspective, the delivery of capabilities that can provide both the incremental improvement and leapfrog efficiency gains that enable customers to achieve, and then exceed, their power goals is what's driving the semiconductor industry. This creates room for new features and functions, making it that much easier for me to live in harmony with my electronics – even when the power goes out.

Intersil
Intersil is a leading provider of innovative power management and precision analogue solutions. The company's products form the building blocks of increasingly intelligent, mobile and power hungry electronics, enabling advances in power management to improve efficiency and extend battery life. With a deep portfolio of intellectual property and a rich history of design and process innovation, Intersil is the trusted partner to leading companies in some of the world's largest markets, including industrial and infrastructure, mobile computing, automotive and aerospace.

Andy Cowell is senior vice president, mobile power products, for Intersil.

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Andy Cowell

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