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Power Hardware Technology

Can Transistors Be Made To Work When They're Off? 89

An anonymous reader writes "Engineers at the Belgian research institute IMEC are looking at the use of silicon transistors in the sub-threshold region of their operation as a way of pursuing ultra-low power goals. A chip the engineers are designing for biomedical applications could have blocks designed to operate at 0.2 or 0.3 volts, researchers said, according to EE Times. The threshold voltage is the point at which the transistor nominally switches off. Operating a transistor when it is 'off' would make use of the leakage conduction that is normally seen as wasted energy, according to the article."
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Can Transistors Be Made To Work When They're Off?

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  • by Ethanol-fueled ( 1125189 ) * on Sunday June 13, 2010 @08:04PM (#32559916) Homepage Journal
    To use a car analogy -- it's like driving the car at idle speed without actually hitting the gas pedal.

    It's most noticeable if you drive a big truck with an automatic transmission -- just shift it into "D" and coast along at .2 miles per hour. You could also do it with a manual transmission, but you'd need very fine control of your clutch-foot.
  • Re:Yes and No (Score:5, Insightful)

    by NevarMore ( 248971 ) on Sunday June 13, 2010 @08:09PM (#32559938) Homepage Journal

    The energy put into thinking about this would far outweigh any perceived benefits.

    Indeed. All scientific research is utterly useless and wasted time unless it has immediate and forseeable tangible benefits.

  • Re:Yes and No (Score:1, Insightful)

    by Anonymous Coward on Sunday June 13, 2010 @08:35PM (#32560096)

    Indeed. All scientific research is utterly useless and wasted time unless it has immediate and forseeable tangible benefits.

    I have to disagree. The pursuit of knowledge can be rewarding in and of itself. Besides you never when some discovery might prove useful. For example, Boolean logic, which is used to design transistor circuits, was invented in the 19th century. It was pretty useless until transistors came along in the 1950's.

  • Re:Yes and No (Score:3, Insightful)

    by Anonymous Coward on Sunday June 13, 2010 @09:00PM (#32560230)

    Sheesh - RTFA already.

    Low power devices have their uses - the article even mentions one, a body-powered medical device. They aren't trying to reduce overall energy consumption.

    BTW, nice inclusion of a political dig in there as well - you must be lot of fun at parties.

  • Re:Yes and No (Score:5, Insightful)

    by Anonymous Coward on Sunday June 13, 2010 @09:02PM (#32560244)

    You're just a fucking ignorant moron.

    This has nothing to do with "green" propaganda and raining on your political masturbation parade, and everything to do with looking at ways to overcome the problems that die shrinkage has on causing waste power from static dissipation to prevent further technology advances, you fuck.

    The summary is only using "off" in an informal sense. In an idealized textbook transistor model, when the transistor is "off" or in cutoff, it is off completely. But in reality, there is leakage, and so this "cutoff" region actually has some more interesting things going on, then a fucking tool like you apparently would understand. With large transistors in CMOS configurations, there is virtually no leakage and no static dissipation. As features have shrunk, the leakage has become a fully technological advancement problem. It isn't just about treehugging, but also the fact that if you get to a certain point where you have tons of transistors in a small space, if you can't remove the waste heat, you've got a major practical problem.

    Get a clue, you useless fucktwit.

  • Re:Not news (Score:3, Insightful)

    by LynnwoodRooster ( 966895 ) on Sunday June 13, 2010 @10:29PM (#32560658) Journal
    No problem! See, you just add a higher voltage rail, and then use that to run the output transistors so you get readable outputs!

    Oh wait...

  • Re:Yes and no (Score:5, Insightful)

    by Thomas Shaddack ( 709926 ) on Sunday June 13, 2010 @10:48PM (#32560746)
    There are devices harvesting power from ambient sources - vibrations, low-level light, small temperature differences, or, when implanted in an organism, using micropower glucose fuel cells. All these offer very very low power. Designing chips capable of operation with power requirements sufficiently low to be fed from such sources is DEFINITELY not a waste of effort.

    Please broaden your perspectives.

  • by Anonymous Coward on Monday June 14, 2010 @12:32AM (#32561204)

    The current into the base of a bipolar transistor has a logarithmic relationship to the BE voltage. That means it is only really off when the base voltage is exactly zero.

    These are MOS devices, which have a squared voltage/current relationship between the gate and source when operated below the threshold voltage.

    I wrote my thesis on this stuff in 1994, and I used a textbook called "analog VLSI" written by Carver Mead at Caltech. There are commercialized cochlea implants available that use this technology. This has got to be the most non-news story I have come across for a long time.

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth. -- Niels Bohr