Last of three parts: Why your set-top box is a power hog and how to increase time between charges in mobile devices; where to find some huge power savings.
Semiconductor Engineering sat down with Sumit DasGupta, Si2; Simon Bloch, Samsung; Jim Hogan, long-time industry venture capitalist; Mike Gianfagna, vice president of marketing at eSilicon (VP of corporate marketing at Atrenta when this roundtable was held). What follows are excerpts of that discussion.
SE: What’s going to really drive interest in low-power technology?
Hogan: The world will get to a point where we will have an energy budget. So if a TV pulls 100 watts, if it actually pulls more than that you don’t care. It’s going to become regulated. If you shut off your set-top box now it still draws 40 watts. Why? Because the disk is still moving. The challenge for us in the SoC world is to be able to shut off the disk and pull 1 watt. That becomes the central issue going forward, not just for mobile devices but for tethered devices, as well. What changes the world as we know it is the regulation and consumption of energy. If you look at the political side, the whole 20th century was about regime changes for energy. It’s not about humanity. It’s about energy, and look what it does for the world.
SE: What will be the biggest challenge in getting there?
Hogan: Initially, it will be the inertia you have to overcome from compliance. The second thing is that we have to have standards in place that say this is how much energy should be required. There are all these standards groups that need to be created. Smart people who know this stuff have to sit down and tell us what they need. Then, we need the ability to validate that in the SoC. I want to know what every IP block does in each mode—standby, full power, sleep and deep sleep. That’s coming. People aren’t asking for it yet. We have tools that try to estimate consumption. But they’re still pretty crude instruments. If we regulate TVs to on power to 100 watts, the first guys will stop it will be the online guys, because they have to boot up Linux every time to turn the TV on. You don’t need that. You don’t need the whole chip.
Bloch: From our mobile perspective, the budget already exists because of the battery side. There’s no need to dictate the budget because it’s already there. The way designs are being implemented today, there’s a lot of waste because of the need to accommodate all the different capabilities—the images, the video, the digital signal processing, the GPU. People throw in processing cores that only know how to do one specific thing. The workload balancing is extremely manual today. A lot of these processors are in idle or sleep mode waiting for the right type of data or processing to be requested. That’s where this waste occurs. There are so many other issues. One is power consumption.
Hogan: That’s certainly an unintended consequence.
Bloch: The way people propose to solve it is a different methodology for designing a complete software-defined hardware system. That methodology needs to be part of the block diagram of the whole system that includes hardware. You create hardware for your system as opposed to throwing in hardware that’s just wasted.
DasGupta: I just completed a leadership training program where every day we tackled an issue that was relevant to the city of Austin. On our energy day, one of our city councilman showed up and said, ‘On average, 90% of the time a car sits idle.’ He’s right. It’s a high percentage of the time. Ultimately it’s about expectations. The reason the battery lasts as long as it does in a cell phone is that the consumer does not want to plug it into the wall every five hours. Do we complain that we take a laptop and plug it into the wall all the time? No. Even after you shut it down you leave it connected. I have expectation that the power is there. If we, as consumers, do not demand our suppliers to comply with an energy limit, then behavior change won’t happen. It’s a behavior change on the part of the consumer, and that feeds into the behavior change by the supplier.
Hogan: So let’s talk about this as it concerns air quality. When I grew up in San Jose, you couldn’t see across the Valley. Air quality was bad. In the early 1970s, they began mandating equipment on cars. Federal mandates for air quality drove innovation. We have cars today that are fuel-injected, they have computers on board, they have catalytic converter, and out the tailpipe is far less. First you have to create the awareness. We already have that. Trying to use a carbon footprint and get everyone to support that isn’t going to work.
Gianfagna: That will drive some serious innovation.
Hogan: Yes, in every way—economically, politically.
SE: What do we do about the transmission loss of power over distance?
Hogan: Conversion on the inverter is 30%, so between that and transmission you’re losing 60%. There are all kinds of spots you can optimize at a system level, and the system level is captured in the SoC.