When engineers start sounding like New Agers, going on about a holistic approach, then you know the problem is serious, perhaps even desperate.
That's what's happening with power management. Few doubt the severity of the challenge or turn away from considering any idea, crazy or otherwise, that may save a microwatt or two. They all add up when designs move to 90 and 65 nanometers, where static power leakage nearly equals dynamic-power leakage.
Nevertheless, it will still take some time before the industry is able to pull together to really make a holistic approach happen. In an encouraging sign, clusters of companies have been pushing frameworks that could eventually lead to some sort of de facto automated approach to low-power design or, in the best case, a standard. That would open up the field to smaller companies that don't have the resources or experience to manually apply low-power techniques.
Anyone designing for low power on 65 nm must use some combination of power-saving techniques. So far, it's usually larger companies, like Freescale Semiconductor Inc. or Texas Instruments Inc., that
are most familiar with techniques such as clock gating, frequency and voltage scaling, and multithreshold transistors, and have the means to track the timing impact of these techniques on a device and verify designs using them.
Voltage islands are also increasingly important, as higher integration of previously separate functional blocks means that designers need to group portions of a system-on-chip according to power needs and allow them to operate at independent voltages that can be selectively gated to reduce power consumption.
TI, for instance, first introduced its suite of SmartReflex power-management technologies at 90 nm. These tools leverage voltage and frequency scaling, and forthcoming enhancements at 65 nm will include adaptive voltage scaling (AVS), a method by which the voltage is increased or decreased to meet the changing performance requirements of an application. SmartReflex also includes a software component that monitors systemwide activity and makes choices about the level of performance needed.
"Some of the products coming out this year are starting to take advantage of these capabilities. The products that come out next year will take it a notch above, when they use 65 nanometer and incorporate all the latest SmartReflex technology, like AVS," said Brian Carlson, core technology manager for Texas Instruments Cellular Systems Solutions. "In 2007 and 2008, there will be very dramatic increases in performance in terms of standby time for cell phones."