Power Management Trumps Battery Technology

Despite gains in extending time between charges in portable electronics, very little of that progress comes from the battery.

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By Ann Steffora Mutschler
The lithium-ion battery has the power to ruin someone’s day, especially when it dies and cannot be charged, not to mention occasional thermal runaways that literally cause explosions. For a technology that is about 30 years old, and approaching its limits, it is mind-boggling that the best brains on the planet haven’t come up with a technological superior alternative.

But alas, they have not—at least from a realistic cost perspective. While the world waits, electrical engineers and system architects are leveraging power management techniques in the design of chips to do everything they can to make their system as efficient as possible to gain a bit more battery life.

As such, the power management IC industry is healthy. Marijana Vukicevic, principal analyst for power management at IHS iSuppli, predicts the global market for power management semiconductors will reach $36.2 billion in revenue this year, 13.9% higher than $31.8 billion last year. However, she expects growth to slow this year to bring revenues back in line after tremendous growth last year.

This move toward more efficient battery-powered devices is driving continuing demand for power management ICs as consumers everywhere look for longer battery life in their mobile devices—with new design trends likely to emerge in power management ICs, Vukicevic said.

Growth in alternate energy markets, including solar, wind, the electrification of vehicles and the smart grid also will drive growth, along with a move toward greater integration in power ICs. Those suppliers with the technology to further integrate their chips will reap the greatest benefits in terms of revenue.

“There are trends that are pulling several power management ICs into one, which is understandable for some devices,” she said. “Then there are times when some of these functionalities are coming from power management ICs that had already been integrated because the OEMs are looking into having more flexibility or they really want to add a feature that no one else does.”

Understandably, for tablets and iPads, there is a lot of integration because space is restricted and form factor is an issue.

When it comes to techniques, there is always a different issue, she noted. “Whether it is the battery charging, whether people are trying to figure out the best way to charge the battery without damaging the battery because you have to keep the current flowing—there are different techniques that people are applying. Some of these techniques are IP-protected, some of them are not. You do have companies looking into that, of course, because it is a big issue.”

Discrete chip vs. embedded block
In designs today, power management is implemented as discrete devices in a system or as part of the SoC, with the exact breakdown difficult to nail down.

“We have seen both types that are on-chip power management functionality available. There’s a lot of off-chip. It depends if you have a single SoC system. Then the power management has to reside typically on the SoC itself. That would be one reason to put it on the chip,” said Krishna Balachandran, director of product marketing for low-power verification products at Synopsys.

The job of the system architect is challenging. First, before even deciding how to implement the power management, the architect has to determine how to proceed. “There are a plethora of techniques that are available and the architect has to figure out which ones he/she wants and how to partition the design into a number of power domains. So that’s an architectural problem. Even before that, the architects decide how much they want to control power at the system level vs. using software vs. the hardware chip level. That’s a tradeoff they make early on,” he said. “Usually, whatever they are not able to achieve from a system perspective and from a software control perspective, that’s when they start putting the onus on the chip design itself. The system architect goes through a process, figures this out, and then says to the chip design team, ‘You’ve got to deliver me this power for this particular chip.’”

Looking at the smart phone market, there is also a trend toward integration of power management. “There are still functionalities that are outside that one particular IC, but there is a trend of integration because otherwise they would end up with a bunch of different ICs that take up space. Major power functions are integrated with the supporting ones that are not,” Vukicevic said.

The design approach depends on the OEM. “Between OEMs, there is a differentiation on how they do things. For example, sometimes you’ll find an OEM who buys a digital baseband from Qualcomm, for example, and then they buy an analog baseband from Qualcomm, and either power is integrated in that analog baseband or Qualcomm supplies an IC with power management,” she noted.

On the other hand, some OEMs pick and choose how the power is going to be managed. And finally, there is a top layer where software manages power consumption within the device—a layer of firmware and software that is above the hardware, Once you plug in to all of the hardware inside, there is a layer of firmware and a layer of software that is closest to the user, where the user actually can influence power usage, Vukicevic said.