Indianapolis (IN) - How much of our input electricity is wasted as heat in the A/C to D/C power conversion?  Inefficient power supplies can be the single biggest component keeping our "green computers" from achieving their full levels of greenness.  A company called Marvell, a member of Climate Savers, has brought forth a new chip which addresses that power gap.


Inverter technology
Marvell has produced CMOS-based 88EM80xx power converter chips, 88EM8041 for the desktop, 88EM8011 for the notebook.  These are used, basically, to receive A/C wall outlet power and correct it on the fly to whatever power form is required by the rest of the device.  These chips can receive 90 VAC to 260 VAC input, and will manipulate and correct the A/C waveform, including amperage, to produce a constant, smooth 120 VAC output (or 240 VAC, depending on model) at up to 250 watts max per chip.  The chips can be put in parallel to increase in steps to 500, 750, 1000, etc.
  
 


  
  
 
Because of their design and what they do, these chips reduce by twenty the number of components required for conventional A/C to D/C power converters.  This ultimately reduces the power supply cost, but the real savings comes in the form of long-term use as these chips have been shown save 50% or more in power consumption.  Some of Marvell's claims have ranged from that 50%, or 2x saving, all the way up to 7x.  These are based on commercially available power supplies being compared to their efficiencies.

Note:  The 50% savings is the minimum amount reported by Marvell.  They told us they've seen much greater power savings in the lab.  These have come primarily when power supplies reach fringe limits of their power generation where efficiency curves fall off notably.  TG Daily has been promised to receive a power supply so we can independently verify these claims.  However, at the time of this publication we have not yet received one.


How does it work?
A/C power arrives at our wall outlets in what's called single phase.  This power signature consists of a single alternating cycle of voltages across two wires on the power cord.  These range from 0 to a little over the maximum rated voltage.  In the U.S., we're supposed to receive a 120 volt supply and 60 Hz frequency.  Some other countries use 50 Hz frequencies and different voltages.  The bulk of the amperage is transmitted near the peak of the voltage.  According to Marvell, the amperage is not always ideally lined up with the voltage peaks.  This results in electrical distortion and great inefficiencies as the bulk of the current is being received at a lesser voltage.  Note:  Electrical voltage and amperage can be visualized like a water hose.  Voltage represents the pressure, and amperage represents the volume.  These equate to how far the water would shoot out, and how big the stream is that flows (the hose diameter).

Marvell's chips basically intercept that raw A/C power, which can have many deformities from the ideal, and adjust it to a correct waveform.  Marvell's chip makes adjustments 300,000 times per second.  These can absorb wide voltage spikes and dips in real-time.  In addition, many rural areas do not operate at a standard 120 VAC.  Marvell's chips take whatever the wall is supplying, a range of input from 90 VAC to 260 VAC, and corrects it on the fly to the constant 120 VAC (at up to 250 watts per chip).  This corrected electrical output is then fed into to the rest of the A/C to D/C converter circuitry, which can now be built to more rigid tolerances, achieving greater efficiencies due to the known constant input.
  
 


  
  
 
The realization
Just how much power is wasted by the conventional power supply?  According to Marvell it can be in excess of 50%, meaning our machines use twice as much electricity as they should.  According to the EPA, there are more than 10 billion separate A/C to D/C power converters in the world, with more than 2.5 billion in the U.S.

Take a 120 watt CPU, for example.  Because of modern power supply inefficiencies, it could actually be consuming well over 240 watts at the wall.  The same is true with those high-end video cards, each consuming 90 watts or more.  They could actually be consuming 180 watts or more at the wall.  Multiply that 2.5 billion times and it adds up to $3 billion per year wasted as heat in the U.S. alone, according to the EPA.

Power supply companies have provided graphs indicating each model's efficiency at given workload, for a long time.  Many power supplies might be rated at 600 watts, but their efficiency falls off greatly above, say 400 watts.  This can result in more than double the electricity cost and a lot of wasted heat.  According to the Electric Power Research Institute (EPRI), the power supply in a typical desktop PC today is only about 65% to 70% efficient in normal ranges.  The efficiency curves fall off sharply when pushed near their limits.

Server farms began realizing this several years ago.  They began switching their server rooms over from independent A/C to D/C power conversion on each server (or rack) to dedicated rooms for the conversion.  Wiring then goes out directly to the machines, feeding them directly with D/C power.  This does two things for server farms.  First, it provides a less expensive way to produce D/C power because only one A/C to D/C device is needed for potentially the entire room, or certainly many servers.  Second, it removes a large heat generation source away from the server room and places it somewhere else where the heat can be wielded or removed differently than the closed cooling system used in most large farms.  This can reduce cooling costs significantly, which often account for about half of server room power budgets.


How green do we go?
Many manufacturers are coming out with green hard drives, green CPUs, green video cards, green motherboards, lower power this, lower power that.  It's the new trend and it is a desirable one, but is it really making sense?  If we're still powering our machines by something that's wasting 50% of the electricity coming out of the wall, then what good is it?  Every little bit helps, right?

If Marvell's claims are true, and they can be independently verified, then the potential now exists just by switching the power supply, that the entire machine immediately reduces its power consumption by 50%, and that's without changing any other individual machine components over to green.  That's going real green, and it could also result in real green being in our bank accounts at the end of the year.


Background data
Marvell does not make power supplies.  They make components which then go in to power supplies.  They currently have contracts with OEMs to produce power supplies using their new 88EM80xx chips.  These should be available in the middle of 2008.  Climate Savers is an organization dedicated to spreading the word that power savings in computers can make a difference.  They are dedicated to reducing power consumption and saving $5.5 billion by 2010, at an average 8.85 cents per kW/h.

Marvell began switching all of its campus lighting to energy efficient fluorescent bulbs with programmable ballasts.  This conversion happened before Marvell had completed their current 88EM80xx chips.  As a result, the bulk of their campus does not use their own power saving features.  However, over time they will be making the conversion.


Conclusion
Green products are desirable, especially when they're only marginally more expensive.  We're all sharing this planet after all.  There are both financial and environmental reasons to go green.  What this article should demonstrate is that we can all become greener than we previously thought, not by buying all green equipment, though that might still be a good idea.  Rather, by paying attention to the big power wasters in our modern computer systems, the power supplies.  If we just look a little closer to the wall, perhaps the biggest differences can be made.
 

Very Cool!

Nov 06, 2007 09:55     

I like the "Real Green" line!
Elijah report abuse vote down vote up Votes: +0

This could be huge

Nov 06, 2007 09:57     

Can any engineers confirm this chip? It almost sounds too good to be true.
Paul Wowk report abuse vote down vote up Votes: +0

I want to see the review of this "Possible" PSU

Nov 06, 2007 10:04     

If it does what it says it does... I guess I will wait the 5 years before I buy a better PSU than the cheap off-brand that I have right now.
Temo report abuse vote down vote up Votes: +0

PFC has been around for years. One of the earlier ...

Nov 06, 2007 11:05     

PFC has been around for years. One of the earlier apps was professional audio power amplifiers. PFC allows large amplifiers to consume much less current as compared to thier traditional power supply siblings. It used to take 30 amps @ 230 VAC to get into the multiple kW range for audio power amps. Now you can find PFC amps that deliver 10 kW using similar current draws. Most prominent current pro audio manufactuer using PFC is Powersoft (www.powersoft.it).

Jon report abuse vote down vote up Votes: +0

yeah, when is commercial application coming

Nov 06, 2007 11:06     

I want one of these in my next PSU, any word on companies working with them and when we can expect to see PSUs using this chip?
Niva report abuse vote down vote up Votes: +0

10 Million AC to DC converters in the world???????

Nov 06, 2007 11:07     

And only 2.5 million in the US?? Are they crazy? In my field of view right now are at least 5. In my home are more than 20. My workplace has HUNDREDS. I'll bet there are hundreds of millions in the US alone. Marvell is underestimating their product's value and potential marketplace...
Todd report abuse vote down vote up Votes: +0

Correction: (B)illion not (M)illion?

Nov 06, 2007 11:23     

2.5 million power converters in the U.S.? I think you're off by a few orders of magnitude!
CD report abuse vote down vote up Votes: +0

Plenty of energy efficient power supplies

Nov 06, 2007 11:33     

There are already quite a number of energy efficient power supplies on the market. A common standard is the 80 PLUS standard, which dictates efficiency of 80% or greater from 20% load to 100% load. In my experience, a low-end power supply will have an efficiency of around 65 to 75%. Good power supplies are in the 80% to 90% range, and already take whatever comes out of the wall from 90V to 220V. Given that, I have a hard time swallowing the "50% savings or more!" line. I understand that you can't test their chip without one, but surely you can examine the other claims in their prospectus? Of course, if this makes high efficiency power supplies cheaper and more common, that sounds great to me!

Joshua report abuse vote down vote up Votes: +0

DC power.

Nov 06, 2007 11:40     

It's a good idea. On the other hand if more houses had direct DC power outlets this wouldn't be such a big deal. I'm one of a few percent who run direct DC power for all my outlets so it's just a matter of getting a new adapter for my appliances. For the rest however this is a good idea, and hopefully chips like these will make there way into electrical appliances in the future.
stick report abuse vote down vote up Votes: +0

50% efficiency is pretty extreme

Nov 06, 2007 11:55     

While there may be a few PSUs that are that inefficient, most are commonly in the 70% range. A few very good ones are 80% and higher. I have a feeling they are claiming horrible numbers to make themself look good. However, I am interested to see how much of a difference this chip can make. If we can get PSUs that are 90% efficient or better, then we can reduce electricity usage and heat generation quite a bit.

AtomRend report abuse vote down vote up Votes: +0

cost?

Nov 06, 2007 12:02     

Sounds great... My question is, how much do we have to pay in order to 'save' money? I don't recall seeing the effect this new chip will have on the price of a power supply.
grcunning report abuse vote down vote up Votes: +0

Time frame

Nov 06, 2007 12:24     

What is the time frame for a product launch? Two years?
Hammerhorn report abuse vote down vote up Votes: +0

If it does what it says it does...

Nov 06, 2007 12:53     

...then I would suspect power savings in the range of 10% on average. It is true that on a very bad source of AC, like some rural areas, the saving can be 50% or more. Generally speaking, in urban areas, power is very close to the requirements(both in voltage amplitude and current phase) thus lowering by a big factor the gains. If this chip is affordable, then it makes sense to use it in future products even if the savings are 5% or below. All I have said here are rough estimates based on experience, so the 50% figure can be indeed common in practice, but I very much doubt it.

Compres report abuse vote down vote up Votes: +0

Waveform and power factor conditioner?

Nov 06, 2007 13:13     

From what I read this thing is basically correcting the waveform and power factor to output an "ideal" and very clean 120VAC/60Hz source for a power supply to convert to whatever the load is. Trying to remember what I learned in school. By getting the power factor closer to ideal, which is 1, you can get the same output power on a power supply with less input power, resulting in increased efficiency. Cant remember exactly what a unstable frequency will do to a power supplys performance

ZZZ report abuse vote down vote up Votes: +0

No cost difference

Nov 06, 2007 13:56     

In theory, the cost of the chip should be offset by the simplification of the down stream circuits. As it's doing the voltage clean up I would imagine a great number of capacitors down stream could be dropped. Even if thats not the case, I'd spend an extra $10 to save half my E costs.
GZ report abuse vote down vote up Votes: +0

Efficiency

Nov 06, 2007 14:30     

The circuit will consume energy, there is nothing that can be done about it. To actually save power, it has to add to the efficiency more that what it consumes. Now, inefficient power supplies are plenty, but in a PC, 70% efficiency is rather usual. To go above that is difficult, especially if the only tool is a stabilizer/PFC circuit. In addition this circuit does not correct the power supply, it just helps it with stable alimentation. I'll take that 50% power saving with a huge grain of salt -- like: make it 10%.

SurJector report abuse vote down vote up Votes: +0

I'm in 100%

Nov 06, 2007 15:01     

So the chip will be available in mid-2008. Most PSU that claim 80% its a @$#% joke. I had to replace my fan on my PC TURBO-COOL 510. I purchase $65.00 Antec TruePower 650 for temporary until the fan arrive. My TURBO-COOL was 10%-12% more efficient than Antec.
Sal report abuse vote down vote up Votes: +0

Is this just improved power factor correction?

Nov 06, 2007 17:18     

If so, then I am no longer excited. All active PFC does is help the computer appear to be a simple resistive electric load, rather than a complex load with inductance and capacitance to account for. Complex loads like these, where demand for electric current is not always in phase with the voltage delivered, are the main cause of the distortion on the mains that you talk about. But PFC has been around and quite effective for a long time. There are houses around where I live that have PFC units mounted next to their breakers. But the end result isn't huge savings from what I've read--it's more predictable, manageable electric load for the power company so they don't have to spend so much overbuilding their equipment. Homeowners might save a little at the meter, but the real savings is indirect, assuming the cost per kilowatt is lowered. I rather doubt it would be, knowing my power company >_> But from the (very small) picture, it looks like the new chip might be involved somehow in improving the switched mode circuitry... I dunno, I could be wrong about all of this. What I do know for certain is that my newer power supply is 80-plus certified and never seems to expel hot air, no matter how great or how small the load is. That's encouraging :)

Tom report abuse vote down vote up Votes: +0

I bet Al Gore is green with envy!

Nov 06, 2007 21:34     

I bet Al Gore is green with envy that he didn't invent this along with the Internet!
Dozer report abuse vote down vote up Votes: +0

A little more info

Nov 07, 2007 01:07     

It is a PFC digital control chip. From Marvell's website: http://www.marvell.com/products/power/pfc_controllers/index.jsp Nothing too spectacular, but it hopefully is a improvement.
Paul Wowk report abuse vote down vote up Votes: +0

power factor

Nov 07, 2007 04:02     

This is not about actual efficiency of PSUs but rather about efficiency of power delivery channels (wires). If you have a bad power factor (lots of idle current but little effective current), it means that current goes over the wires to you and then back to your supplier (unused) and part of it disspites as heat over the cables' electric resistance. By elimination of idle current you eliminate the extra losses on the wires between you and the power plant. Anyway, regular consumers are charged only for the effective power they consume (this is what power meters usually measure), not the idle power (that is just transported forth and back). Only major electric consumers (factories etc.) are charged extra money if they don't meet the required effective/idle power ratio. Normal people don't even need to care as long as they don't have to pay for it.

The Preacher report abuse vote down vote up Votes: +0

Re: cost?

Nov 07, 2007 12:22     

you are saving money however you look at it. Even a $100 plus in the PSU price can be offset with a couple of years of power saving.
gonchuki report abuse vote down vote up Votes: +0

Problem with their 'maths'

Nov 09, 2007 11:57     

Ok. So this chip is so great. Let's say it's 100% efficient. Let's take 70% as the efficiency number for a given 'common' psu. Let's even say it drops to 50% when running at high load. Keep in mind a 70% efficiency PSU is likely a cheaper model and unlikely to actually run at 100% rated load for more than a second or two. So 50% vs 100% efficiency. Depending on your 'maths' that's either a 50% improvement (50 50=100) or a 100% improvement (50 100%*50 = 100). I'm not quite sure where this 7x improvement comes from. For that your PSU would have to be ~15% efficient...i.e. waste 85% of it's energy as heat. Now, those PSU's are common...they're called space heaters. I put one in my bathroom. I doubt they'll improve much on it with this chip though.

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