Power reduction
Shaving peak load
78M661x energy measuring IC
Inphi iMB IC
At Semico Research’s “Technology in the Palm of your Hand” held March 2 in San Jose, the focus was on smaller, faster, and cheaper technology as usual but a new “must have” was added to list. With an increasing amount of features, power management is critical in handheld products – if the user expects to have any reasonable length of operation on the rechargeable battery. In spite of the conference title, more efficient use of power was noted throughout the daylong event as a critical factor in data centers, cloud computing, smart grid and hybrid vehicles, too, going well beyond hand-held products.
Ana Hunter, vice president of Foundry Services at Samsung Semiconductor, noted that power was also a hot topic at the February 7-11 International Solid-State Circuits Conference (ISSCC) held in San Francisco. As Samsung develops its advanced process technology, power is top of mind. “Customers come to us for foundry processes, and power is definitely the top consideration for designers today,” she said.
While traditional metrics of die size and performance (MIPS/MHz) continue to drive the need for increased integration, power now is a very key part of that equation. Hunter observed that concern for power goes beyond handheld products and also applies to servers, server farms and other applications that are power constrained. However, power has special significance in handheld applications. In addition to battery life, excessive power results in heat that directly impacts the user.
As part of the proven silicon results to address increased performance and power requirements, Hunter cited the power reduction (Fig. 1) that was possible when Samsung transitioned from a 45 to a 32 nm process. In one design, by focusing on power reduction, Samsung was able to maintain performance and obtain considerable power reduction. Part of the solution involved lowering the supply voltage from 1.0 to 0.9V, which allowed a 33% reduction in dynamic power, a 55% reduction in leakage power, and 35% reduction in total power. “Today, it does not matter whether it is infrastructure, a wired product or a handheld product, I don’t have a single customer saying there is room for more power consumption in their design,” said Hunter.
MEASURING IMPROVEMENTS
Hunter established a rallying cry for power that many subsequent speakers supported. Measuring improved efficiency is a critical power area that Jay Cormier, vice president and general manager of Teridian Semiconductor, addressed. One rapidly growing area for power consumption is data centers where 1/3rd of the variable cost at large installations goes towards power and cooling. In the next five years, the expense to power and cool the worldwide installed base of servers is projected to increase at 4x the growth rate of new server spending. Cromier commented that U.S. data centers consumed 61 Billion KW-hr in 2006, 1.5% of total electricity use, and that it is doubling every 5 years.
To find out how they measured energy efficiency, Cromier discussed the topic with several potential customers. “I was quite surprised to find that these customers when they are selling systems into the data center, can win or lose business based on 1% power efficiency of their servers, but they can’t measure it to better than 5%,” he said. Government regulations will play a role to increase the awareness for improved measurements. “Later this year, the Tier 2 Server Spec from Energy Star is going to start mandating a certain level of real-time accuracy in energy measurement inside the power supply inside the servers,” said Cromier.
With the U.S. government goal to have 1-million hybrid and electric vehicles on the road by 2015, plugging those vehicles into the grid will increase household electricity consumption by 50%, potentially during peak loads, creating another power problem. Since electricity usage during peak hours drives utility infrastructure spending, reducing the peak demand (Fig. 2) is required to avoid unnecessary infrastructure expenditures for increased capacity that will take years to put in place. In addition to pricing structures, smart chargers are required to reduce charging during peak power.
At the home level, reduced energy consumption involves “getting consumers to change their behavior and make those investments so they can save more (energy),” says Cormier. From a semiconductor perspective, Cormier thinks that a complete solution with compelling price points can make an embedded solution a reality in numerous applications. Teridian’s solution is the 78M661x energy measuring ICs (Fig. 3). “You can embed that in anything from an appliance to a smart plug. People want something very small, tiny, to be able to make it ubiquitous,” he says. The complete solution comes from an IC with firmware as well as a calibrated Outlet Monitoring Unit (OMU) and OMU firmware. The IC has an analog front end with high accuracy and dynamic range, a dedicated 32-bit metrology engine for power measurement and an 8-bit MCU with embedded Flash memory for housekeeping functions.
POWER TO THE PEOPLE
With a keynote presentation title of “Power to the People,” you would expect a lengthy discussion on power and perhaps reference to the civil rights movement of the 1960’s. After a slight reference to the latter, Jack Harding, chairman, president and CEO of eSilicon presented some insight into power with both engineering and political perspectives. From the political side he said, “The notion of energy and power management has become central to every country’s foreign policy.”
Focusing on the United States, Howe explained the relationship of political power to engineering power. “Our nation is engaged in a great debate around the production, the sourcing, the distribution and even the defense of our power resources,” he said. Scarce power resources have created a third convention adding to the existing semiconductor industry’s pivotal areas of computing and connectivity. “Power management has become not only something with which we transact when we make a chip, when we build a system, it’s not only something which we have to consider while we are deciding the use level for our own devices, it’s also an issue we must consider as we go all the way up the public policy \\[ladder\\] and how it impacts our day to day operations.”
Harding believes a power-centric culture based on applications, devices, infrastructure, invention and innovation is evolving. “I think we are rapidly moving to a power-centric world, which is going to reach well beyond our borders to where political power will be determined by access to energy and power and those people who can make the most effective use of the power that is available to them in devices that change other people’s lives will be the winners,” he said.
In the GreenTouch consortium, technologists, academics and government researchers have come together to reduce the carbon footprint through power reduction. The consortium has set a goal of reducing the power consumption of the global internet computation and networking infrastructure, the energy consumption per user, by a factor of 1000x by 2015. “The theory associated with this power statement suggests that there is a 10,000x opportunity,” he said. Based on the advancement that the semiconductor industry has made over the years in several areas, Harding feels the 1000x improvement is achievable within a relevant timeframe.
POWER IS EVERYTHING
Three subsequent semiconductor company presenters made a strong case for improved power management and lower power consumption in the computing and networking infrastructure. Bradley Howe, vice president of engineering for Altera was quick to agree with Harding. “Power is everything,” he said referencing the movie Apollo 13 where the astronauts survived a space catastrophe by focusing on power management. “There isn’t an element, a system, a semi, a software design now that isn’t power aware. It’s clearly here to stay,” he continued.
Howe showed that the massive explosion on the infrastructure side from voice being superseded by data and data being superseded by video has created an unprecedented need for more bandwidth. Typical bandwidth growth from 2008 to 2013 includes an increase of 141 % in internet video TV, 131% in mobile data, 110% in the set top box, 80% in netbooks and 58% in internet video communications. As a result of the growing need for bandwidth, the semiconductor sector faces several challenges forcing new approaches he said. Focusing on power is an essential part of the solution. “There isn’t one element of what we do in my organization now developing new FPGA technology that isn’t power aware design. It affects everything we do. It affects product positioning. It affects architecture. It affects design techniques. It affects rollout. It affects the way we do everything,” Howe said.
Lisa Su, senior vice president and general manager at Freescale Semiconductor, gave some hard numbers to their efforts to reduce power consumption for Long Term Evolution (LTE) technology in wireless infrastructure. “Wideband is much, much closer to a base station on a chip,” she said. “With that integration, you can get much higher performance, much lower cost and much lower power (consumption).” Su showed that the next generation 45 nm LTE solution using DSP and MCU technology was 50% more energy efficient, while providing a 4x increase in performance, 60% cost reduction and smaller footprint.
Young Sohn, president and CEO of Inphi, focused on the increasing memory requirements of cloud computing noting that among the driving forces for cloud computing, a CIO survey of top data center concerns identified the highest concern was power and cooling. Today, the major power consumption point in a server has changed. “CPU clearly has been the problem in terms of power but memory is becoming an issue,” he said.
Sohn showed how memory will be the largest consumer of energy in the server. In the next generation server, the CPU power consumption is almost 400 W, while the memory approaches 500 W, almost twice the level of an existing design. Using iMB (Isolation Memory Buffer) technology, Sohn says that active memory power consumption can be reduced from 144 W to 96 W while doubling the memory module capacity and using half of the number of DIMMs per server. This can result in a data center energy savings of 30 million kW-hr with an annual cost savings of $3 million from direct and $3 million from reduced cooling costs. The calculations are based on a data center with 70,000 servers consisting of 1000 racks with 70 servers/rack. The average capacity of each server is 192 GB and the energy cost is $0.10/kW-hr.
The Inphi iMB IC reduces the burden on the host controller of driving long traces of data, command and control signals. Load reduced DIMM (LRDIMM) with an iMB (Fig. 4) provides a memory-buffer architecture that isolates the memory from the CPU. In addition to improved signal integrity, this increases server memory modules’ capacities from two to four times while operating at much higher frequencies. The combination of these factors reduces the system power consumption.
The excitement for the semiconductor industry recovery of Q1 2010 up 50% over Q1 of 2009 and the 2010 annual growth rate up 24% forecast by Jim Feldhan, president of Semico Research was a great way to start the conference. However, the consistent message and attention to a previously overlooked detail of power management made Semico’s Technology in the Palm of your Hand conference extremely relevant.