Intel's Haswell Moves Voltage Regulator On-Die

MojoKid writes "For the past decade, AMD and Intel have been racing each other to incorporate more components into the CPU die. Memory controllers, integrated GPUs, northbridges, and southbridges have all moved closer to a single package, known as SoCs (system-on-a-chip). Now, with Haswell, Intel is set to integrate another important piece of circuitry. When it launches next month, Haswell will be the first x86 CPU to include an on-die voltage regulator module, or VRM. Haswell incorporates a refined VRM on-die that allows for multiple voltage rails and controls voltage for the CPU, on-die GPU, system I/O, integrated memory controller, as well as several other functions. Intel refers to this as a FIVR (Fully Integrated Voltage Regulator), and it apparently eliminates voltage ripple and is significantly more efficient than your traditional motherboard VRM. Added bonus? It's 1/50th the size." Update: 05/14 01:22 GMT by U L : Reader AdamHaun comments: "They already have a test chip that they used to power a ~90W Xeon E7330 for four hours while it ran Linpack. ... Voltage ripple is less than 2mV. Peak efficiency per cell looks like ~76% at 8A. They claim hitting 82% would be easy..." and links to a presentation on the integrated VRM (PDF).

Comments

excited

[Anonymous Coward]

come guys, comment, so I know how excited I should be

Re:excited

[Anonymous Coward]

The 1.2V regulator will actually produce 1.199988484939848 volts !

Re:excited

[Anonymous Coward]

Ahh Slashdot, the very finest in jokes that were funny in the mid 90's... And thus concludes my bi-monthly check to see if it has gotten any better.

Re:excited

[Lotana]

All good guys, he is gone. We can go back to our regular insightful, interesting and funny posts again.

Re:excited

[Anonymous Coward]

First post?

sinking heat?

[p51d007]

with the on die regulator, won't that area of the chip be a tad warmer than the rest of the chip, or will the heat be a moot point?

Re:sinking heat?

[dotgain]

Heat hopefully won't be an issue. Let's hope heat output scales at least somewhat with component size that is 98% smaller.

And why would it do that? A given voltage drop multiplied by the current through it equates to a certain wattage of heat dissipation, regardless of the size of the package.

Re:sinking heat?

[adolf]

Your broad generalization is only if it is a linear regulator. Switch-mode regulators change the game. TFA doesn't seem to indicate which it is.

Re:sinking heat?

[__aaltlg1547]

It's a switch-mode (Buck) regulator. You can tell from the efficiency curve and the fact that it requires an inductor. It is more efficient than a linear regulator and less efficient than a good external Buck regulator. However, being on-chip it will regulate the voltage better because there won't be significant I*R drop between the regulator output and the load. And as they mention, the cooling fan will be right on top of it, so it is more effectively cooled than an external regulator typically is.

Re:sinking heat?

[AvitarX]

Heat is energy, and it dissipates over time, energy / time = power.

Re:sinking heat?

[viperidaenz]

The voltage regulation issue can easily be solved by having a feedback connection from the die to the external VRM.
There are only two benefits I can see:
1) Higher voltage in to the chip means lower current, which saves power. You I*R formula is slightly wrong, its actually I^2 * R, double the current means 4x the power loss.
2) Lower system cost. the more crap that gets stuffed on the die/in the chip, the less is required on the board. That means fewer components, smaller board area and quicker assembly.
There are of course other benefits that only benefit Intel
a) Fewer external components means they can charge more for their chip without effecting system cost.
b) smaller system = happier customer = will pay more
c) If it does actually result in lower power, then you get more performance or more battery life = customer will pay more

Re:sinking heat?

[adolf]

I figured that it must be that way, but with the power required by a CPU such a regulator must either very noisy and/or require substantial capacitance and/or use ridiculously high frequencies.

So. Filtering? These might be the most expensive mass-produced caps in the world if they're also on-die.

Re:sinking heat?

[viperidaenz]

Watts is used to measure heat.

http://en.wikipedia.org/wiki/Thermal_resistance

The unit is "degrees per watt". As in "5C/W" = "this heat sink will rise by 5 degrees dissipating 1 watt"

Re:sinking heat?

[cats-paw]

seems like they could have beat the IR drop by simply bringing out sense lines.

it's not obvious too me how this helps intel.

unless of course the motherboard makers aren't doing a very good job with those external regulators because the intel chips now require such high performance regulation.

that's a distinct possibility.

Re:sinking heat?

[SuricouRaven]

I rather doubt Intel managed to cram the inductor on-chip too, so doesn't that defeat the point?

Re:sinking heat?

[kasperd]

with the on die regulator, won't that area of the chip be a tad warmer than the rest of the chip, or will the heat be a moot point?

The summary says 76% efficiency. That would mean 24% of the energy you put into the chip is turned into heat by the voltage regulator. Sounds like a valid concern to me.

Re:sinking heat?

[wikdwarlock]

Nope, they actually did get on-chip magnetics and inductors. They're the Intel folks, afterall.

Re:sinking heat?

[ericloewe]

Don't underestimate Intel's ability and will to put all kinds of things on-chip.

Re:sinking heat?

[kasperd]

76% efficiency (24% waste) is for 1 cell i assume for 20 cells it would be 1.2% waste ( 98.8% efficiency)?

What sort of construction reduce waste by adding cells?

Re:sinking heat?

[Luckyo]

Considering the significant heat output of the cores themselves, VRM's heat output is likely trivial in comparison and will be vented into the heat sink alongside the rest of heat.

Re:sinking heat?

[dingleberrie]

You I*R formula is slightly wrong, its actually I^2 * R, double the current means 4x the power loss.

You both have good points, but I think that Shavano didn't mean power.
He meant the Voltage (I*R) drops from the external chip where R comes from the losses of extra traces and pins before it gets to the CPU. The reduction in R means that a variation in I will cause less variation in V as seen by the CPU.

Re:sinking heat?

[Meeni]

Voltage regulators fail often. Wouldn't that decrease the operational life of the processor (I know, a concern only for people that keep operating old junk for a long time, the processor will be well past its prime when it would fail, but still a valid concern for long amortization systems).

Re:sinking heat?

[jcdr]

Voltage regulators fail often.

And you want to replace them with what exactly ?

In my experience the capacitors and transistors are the two parts that can die early, mostly because of thermal stress, due to slow chemical change of some of there properties: the resistance tend to increase and the capacity tend to decrease. I really don't know anything about the chemical stability of the components integrated into the die, but I can see some interesting points: 1) The capacitors are composed of the metal layers of the die. There is no electrolyte involved, so there must be very reliable, like ceramic capacitors. 2) The transistors will probably be cooled more efficiently than in most actual motherboard.

So there is possibility that this new design will increase the reliability. This argument is still speculation as there likely rely on a first stage standard switching power supply to lower the voltage at an acceptable level for the die...

Re:sinking heat?

[InvalidError]

The voltage regulation issue can easily be solved by having a feedback connection from the die to the external VRM.

Not quite. Part of the reason why Intel went for FIVR is due to response time.

Haswell can change power states about 10X faster than SB/IB and needs a VRM that can adjust voltage outputs that much faster to minimize wasted power and time. The motherboard's VRM has a response time measured in tens if not hundreds of microseconds due to how far away it is from the load, how large its components are and how slow it is operating relative to its load - Haswell has time to wakeup/sleep a few times in the time it take most regulators to adjust to SB/IB's state changes. FIVR's much more tightly coupled components and load bring response time down to microsecond scale to better accommodate Haswell's highly dynamic power usage so the motherboard's VRM does not need to respond impossibly quickly.

FIVR being only ~82% efficient (at least in Intel's experimental design) is somewhat of a disappointment but to be expected when converting low voltage to even lower voltage at high currents. Since there isn't much that can be done about reducing losses on the output side, the most obvious way to improve losses on the input side would be to increase input voltage. 3.3V and 5V seem like logical next steps up for desktop parts if they can be accommodated.

Re:sinking heat?

[Meeni]

The only difference is that before you replaced the main board for a smaller price than getting a new processor. But yes, maybe the fab process will improve reliability overall. Just asking questions.

Re:sinking heat?

[InvalidError]

Poorly designed regulators with poorly chosen components fail often. What kills most PSUs in my experience is failure to use capacitors with adequate AC current ripple rating which causes capacitors to heat up, dry up and inevitably fail. I have repaired a bunch of such PSUs over the years using capacitors rated for 3-4X higher AC ripple and none of them have failed afterward to my knowledge - two of these are in my PCs which have been on almost 24/7 for 5+ after the repair. The oldest of my refurbished PSUs is about 13 years old (11 since repair) and was still kicking when I retired the PC it was in late last year.

It is pretty sad that less than $1 on the BOM separates a PSU/VRM that lasts 1-3 years from one that lasts 7+ years.

Expertly designed regulators with quality components rarely fail unless there is a catastrophic failure upstream or downstream from them.

My bet is that FIVR will lead to a net reliability improvement by taking the most delicate part of voltage regulation on-die where Intel has full control over quality using ceramic/glass capacitors, inductors and MOSFETs all tightly integrated in an equally tightly controlled process.

Re:sinking heat?

[InvalidError]

The other efficiency quote says ~82% with planned design tweaks and even better efficiency hinted at for future iterations.

In any case, if individual cells have 76% peak efficiency, it does not matter how many of them there are, the overall regulator cannot be more than 76% efficient. However, it can be less efficient if the load drifts too far off the cell's peak efficiency point which is 8A/cell in the prototype so FIVR would need to enable/disable cells to keep average load as close to that as possible or at least within the 5-12A range if FIVR behaves like the IVR prototype, which would keep efficiency above 72%.

Re:sinking heat?

[viperidaenz]

True. The voltage drop can be compensated for by sensing at the point of load, not the regulator output though.

Re:sinking heat?

[Anonymous Coward]

Watts is used to measure heat.

http://en.wikipedia.org/wiki/Thermal_resistance

The unit is "degrees per watt". As in "5C/W" = "this heat sink will rise by 5 degrees dissipating 1 watt"

No, watts are not used to measure heat. As the very wiki page you linked says, it's thermal resistance which is measured in units of degrees per watt. Thermal resistance is not the same thing as heat! Temperature isn't either.

The SI unit used to measure heat (and all other forms of energy, including electrical and mechanical) is the joule. One joule is enough heat energy to raise the temperature of one gram of water by 0.24 degC. (A more precise relationship: 4.186J raises the temperature of 1 gram of water by 1C.)

Watts are the unit of power, and they're a rate unit derived from joules. 1 W = 1 J/s. So if you run a 10W heater for 10 seconds and all that heat is captured by 100g of water, you've delivered 100J of heat to the water, which raises its temperature by 0.24 C since there's 1J per 1g water. (The general equation for this: Q = c * m * delta-T, where Q is the heat energy, c is a constant which varies by the material, m is the mass of the material, and delta-T is the change in the material's temperature.)

Re:sinking heat?

[__aaltlg1547]

Imperfectly. The additional inductance and delay result in poorer regulation.

Re:sinking heat?

[viperidaenz]

delay not so bad when the regulator is running at ~1mhz.
transient response for switching regulators comes mostly from the output caps.

Heat

[girlintraining]

Intel refers to this as a FIVR (Fully Integrated Voltage Regulator), and it apparently eliminates voltage ripple and is significantly more efficient than your traditional motherboard VRM. Added bonus? It's 1/50th the size."

I have yet to come across a voltage regulator that doesn't run hot. Typically, it's one of the hottest components in an electrical circuit. And we're integrated this into a slab of silicon already well-known for getting so hot it can catch fire?

Can someone please tell me why this is a good idea, because all of my experience in electrical engineering says that when things heat up, they become more unstable and prone to failure, and the one thing you do not want going critical is your voltage regulator. If that goes, the whole computer catches fire.

Re:Heat

[Anonymous Coward]

Most likely, because it's integrated into the CPU itself, the voltage regulator can be made more efficiently and thus save power and heat etc. Discrete parts have their limitations, and doing it on-die might just mitigate that.

Re:Heat

[Anonymous Coward]

You're going to run into that heat anyway, whether it's on the motherboard in general or on the CPU. You can't win. But at least it's better to have heat build-up near a heat-sink, so for high-power conditions it might actually be better to put it on the CPU. I'm also an electrical engineer, but thermals are really a mechanical engineer's realm, so I can't run numbers for you.

Re:Heat

[rrhal]

Being 1/50th the size it will be welcome on mobile devices. Not sure that its a good thing for your gaming desktop.

Re:Heat

[fuzzyfuzzyfungus]

My suspicion(if only for die-space reasons, it isn't purely cosmetic that contemporary VRMs occupy a substantial amount of board space) is that is this a 'marketecture' summary of Intel moving some additional voltage adjustment and power gating functions on die, to support dynamic adjustment of power to the greater number of components(multiple CPU cores, possibly independently clocked, GPU, RAM controller, PCIe root, etc.); but we'll still see a bunch of chunky power silicon under serious heatsinks clustered around the CPU socket.

Given that much of the contemporary power savings are achieved by superior idling, rather than absolute gains in maximum power draw, Intel is either going to have to keep moving power regulation on die, or start dedicating even more pins to tiny voltages at nontrivial currents, with the associated resistive losses; but that won't necessarily change the fact that the circuitry that brings the 12v rail down to what the CPU wants is a pretty big chunk of board.

Re:Heat

[Virtucon]

Well even at 10W I'm wondering how they'll address the heat.
With the density of circuits in the adjacent silicon I would wonder how they're providing enough isolation to prevent it from becoming a very small brick.

Re:Heat

[RightwingNutjob]

I can see the logic behind shortening the length of the wire carrying 'clean' power and getting it away from all the other components (read: noise sources) on the motherboard. It also takes the thinking burden away from the chip integrator and motherboard designer (which is a non-negligible bonus for both marketing and engineering).

Re:Heat

[Barlo_Mung_42]

I'm not an EE so I won't pretend to fully understand this particular case but I like it when tech companies reach a bit and try something hard. This may or may not be a good idea but I'm still excited about it.

Re:Heat

[citizenr]

I'm not an EE so I won't pretend to fully understand this particular case but I like it when tech companies reach a bit and try something hard. This may or may not be a good idea but I'm still excited about it.

Thats what she said.

Re:Heat

[Anonymous Coward]

Say you have the choice between using a different SoC (maybe an ARM based system) that needs only one power rail, and an Intel SoC that did not include these regulators. Which will cost less to engineer, and be a smaller, simpler solution?

Remember the one of the many forms of Halswell is a low power solution, with TDP of 10 watts...

Re:Heat

[Anonymous Coward]

Considering that they've already started shipping an actual product, perhaps you should switch modes--from skeptic to sleuth. Start from the proposition that (a) it's possible or (b) they're leaving something out of the marketing jargon. There are a million ways they could do it wrong, and likely only a few ways to do it right. If you start from the proposition that Intel is shipping a working product, then it should be much easier to figure out.

Re:Heat

[girlintraining]

My suspicion(if only for die-space reasons, it isn't purely cosmetic that contemporary VRMs occupy a substantial amount of board space) is that is this a 'marketecture' summary of Intel moving some additional voltage adjustment and power gating functions on die, to support dynamic adjustment of power to the greater number of components(multiple CPU cores, possibly independently clocked, GPU, RAM controller, PCIe root, etc.); but we'll still see a bunch of chunky power silicon under serious heatsinks clustered around the CPU socket.

That's the only plausible thing I could come up with as well. The control logic could go into the CPU, but I don't see how pulling 12V down to fractions of a volt is going to happen on the die itself without it burning a hole through the board; heatsink or not, you can't escape Ohm's Law.

Re:Heat

[sshir]

May be that they still use discrete FETs, it's just control circuitry is on die now. (I'm speculating)

Re:Heat

[Kjella]

Can someone please tell me why this is a good idea

The long story is here (PDF). Motherboard will still do the heavy lifting from 12V to 2.4V, but the integrated VRM will distribute it. Advantage is extremely clean, fine-grained, low-latency and flexible power supply to deliver exactly as much power to where it's needed and probably - this is just speculation on my part - allowing the CPU to work on a wider range of voltages since there's less noise and ripple so you don't need the same tolerance limits. It sounds perfect for smart phones, tablets and laptops that are primarily battery-limited, nice to have for average machines but potentially an issue for overclockers. All you need is cooling though, it shouldn't limit overclocking if you can keep the temp down.

Re:Heat

[girlintraining]

you can't escape Ohm's Law.

Actually you can. It's called a switching power supply.

In other news, a Nobel Prize in Physics was awarded to Anonymous Coward of Slashdot today, after discovering that the laws of physics do not apply to switching power supplies... His next research proposal is on solving the energy crisis by designing keyboards to detect when someone is angry and then increasing the key resistance by piezoelectric effect to generate energy. While it would generate only marginal amounts of power when used by 99.975% of the population, it was recently discovered that the remainder are actually Linux and Apple fanboys who, if fed a regular diet of dismissives via their computer screen, will so furiously hit the keyboards that power for entire cities is easily achievable.

Re:Heat

[__aaltlg1547]

Intel refers to this as a FIVR (Fully Integrated Voltage Regulator), and it apparently eliminates voltage ripple and is significantly more efficient than your traditional motherboard VRM. Added bonus? It's 1/50th the size."

I have yet to come across a voltage regulator that doesn't run hot. Typically, it's one of the hottest components in an electrical circuit. And we're integrated this into a slab of silicon already well-known for getting so hot it can catch fire?

Can someone please tell me why this is a good idea, because all of my experience in electrical engineering says that when things heat up, they become more unstable and prone to failure, and the one thing you do not want going critical is your voltage regulator. If that goes, the whole computer catches fire.

It's cooled by your CPU fan.

Re:Heat

[__aaltlg1547]

Being 1/50th the size it will be welcome on mobile devices. Not sure that its a good thing for your gaming desktop.

That 84 watts is going to rip through your mobile device's battery pretty damn fast.

Re:Heat

[__aaltlg1547]

May be that they still use discrete FETs, it's just control circuitry is on die now. (I'm speculating)

That's an interesting question. They can make a FET with as big a voltage and current rating as they want by just making it many times the size of a logic FET. But they also need thicker gate oxide to prevent Vdg breakdown at multiples of the normal logic operating voltage. Not sure how they would do that. It could add a process step, which would make it expensive.

Re:Heat

[ebno-10db]

Being 1/50th the size it will be welcome on mobile devices.

It's not clear how they measure "1/50th the size". I could be wrong but it sounds like marketing hype. With a switching regulator the inductors and capacitors generally take up much more real estate than the chip. If they have some magic way to reduce the inductor and capacitor sizes it isn't mentioned in the article (and that would be a much bigger deal than just putting the regulator on the die).

Re:Heat

[Charliemopps]

Who said they're going to keep it at 12 volts? A VRM can also be the transformer, but it doesn't have to be. They could ramp down the voltage on the board just like they always did and just have a VRM on the chip that is maintaining a steady voltage. If you read the article they are barging about how little fluctuation they are getting. So it seems like what they are doing here is adding basically an extra regulator on chip so they can have extremely stable voltage. I'm guessing as small as things are getting now, just the trip across the motherboard can have noticeable fluctuations on supply voltages due to EM interference and temp fluctuations, so having a regulator on the chip lets them get more precise. Maybe that precision will let them do some magic on the chip to increase performance or something?

Re:Heat

[ebno-10db]

Perhaps it's vastly more efficient than a traditional voltage regulator? It is, you know, silicon fabbed by Intel. The undisputed leader in chip fabrication technology. (Seriously. They're conservatively at least 2 generations ahead of everyone else)

Maybe one generation ahead, but that's in digital chips. While things like switching regulators can be built on digital processes (it's been done before) it's generally not the optimal process. Maybe they've come up with some clever ways to build better switchers on a digital process than previously, but it's hard to believe it's better than a process designed for stuff like this.

Re:Heat

[petermgreen]

You can reduce the inductor and capacitor sizes a lot by increasing the switching frequency. Of course doing so will likely increase your switching losses but it may still be worth it if it lets you put the regulator closer to the load. Especially given the ever lower voltages that modern chips are running at.

Re:Heat

[ebno-10db]

You can reduce the inductor and capacitor sizes a lot by increasing the switching frequency.

But you can do that w/ an external regulator too. Apparently the secret is on-chip inductors. Now that's impressive. I'm surprised that some of the "analog" companies making switchers didn't come up with that first. I know Intel has good fab tech, but this seems more like the sort of funky thing analog guys would come up with first.

http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf

Re:Heat

[Anonymous Coward]

Actually, no real device is ohmic at all. Even a resistor will heat up with increasing current causing an increased resistance that is non-linear. For us EEs, ohmic devices are our massless pullies and frictionless inclines.

Re:Heat

[marcosdumay]

Thanks, that gets the overall picture.

So, the idea is that they'll get some very nice inductors on die, capable of replacing some much more expensive external ones. Also, they can distribute the load to a lot of paralel circuits, creating the right tension for each part of the chip, and reducing the loss of each circuit.

But really, at 90W, a embebing a 76% efficient (not really an exceptional result) conversor means that you'll need to dissipabe other 28W at peak power. Well, I can't say if this is worth it. Certainly, Intel engineers can say, but won't, and the marketeers will lie anyway.

Re:Heat

[Omega Hacker]

Ohm's law is completely irrelevant to this situation *in the form you describe*. "Burning a hole through the board" would be possible and a simple function of Ohm's law only if they were using a linear regulator to generate the Vcore. But VRM's have been switching DC/DC converters since the 486 days. They achieve a voltage conversion by switching the incoming voltage on and off *very fast*, which results in an output voltage that's a function of the input voltage and the duty cycle of the on/off switching. An inductor (current-smoothing) and capacitor (voltage smoothing) give a nice clean DC voltage.

The differences between on-motherboard VRMs and this new in-package (it's technically a separate chip...) are significant. First off, physically moving it closer means that you're not sending 100+ Amps of current over the 3-4 centimeters of generally very thin copper traces on the PCB, they're sent millimeters through die-bond wires, or even through a solid substrate (no idea what Intel does at that level). There's your Ohm's law coming into play at that level, but the power losses there are relatively minimal since you're talking maybe a few tenths of an ohm. Die-bond wires are going to drop that to 10's of milli-ohms probably, so nothing major but still a positive effect.

The main reason this will generate a lot less heat is because of the *frequency* of the switching. Because this on-board VRM is so much smaller, it can switch the input faster (shorter wires, less parasitic capacitance, less ringing, etc.). This in turn means smaller value components required, e.g. the switch from the monster inductors seen on the motherboard (at maybe 1-2MHz switching) in the slide to the tiny chip-scale inductors on the FIVR (at 10's or 100's of MHz). The end result of all of this is that switching losses get significantly smaller. It's those losses that create heat local to the regulator. If they can for example go from an 80% efficient VRM to an 90% efficient FIVR for a 100W CPU load, they reduce the switching losses from 25W to 11.1W.

Re:Heat

[girlintraining]

Actually, no real device is ohmic at all. Even a resistor will heat up with increasing current causing an increased resistance that is non-linear. For us EEs, ohmic devices are our massless pullies and frictionless inclines.

I'm not a certified EE, but I have built electronic circuits. I know there's a lot of ways to 'cheat' on paper; switching power supplies don't get rid of ohm's law though, they're simply more efficient. Ohm's law is about the relationship between resistance, voltage, and current. Those relationships are derived from the physics about electron exchange between different materials. Now yes, capacitors and inductors both run 90 degrees out of phase between voltage and current so it can appear to be violating ohm's law, but if you apply a correction factor you'll see it's pretty close to parity. When you get down to really small discrete components, like a transitor for example, measurement inaccuracy and time domains will really start to screw with you, but ohm's law still holds even down to that scale.

Ohm's law is the reason for these changes Intel is making: An attempt to remove parasitics from the circuits, which all boil down to resistance; Whether it's phase-shifted forward because of capacitors, or backwards because of inductors, or because of components that create those effects, doesn't really matter.

Now you're right, a purely ohmic device doesn't exist. Even resistors can generate small amounts of phase shift. But that doesn't make them "massless pullies" or "frictionless inclines". Ohm's law is still useful for the same reason the OSI 7 layer model is still useful, despite no network yet having been designed that perfectly adheres to it...

Re:Heat

[l3iggs]

But at least it's better to have heat build-up near a heat-sink

True, that it's a good thing that the CPU heatsink is nearby to cool the regulator, but having it on dye also means that the CPU is nearby which seems to be a bad thing from a system stability standpoint.

Something tells me the folks at Intel have carefully considered all this and that the extra capacity the CPU heatsink now needs to keep the CPU stable is preferable to having an on motherboard Vreg, which is relatively far away from the CPU and that they can't trust to be cooled properly.

Re:Heat

[swalve]

Sure you can. Voltage regulators aren't just resistors any more. You divide the 12v @ 1 amp into 1v @ 1amp at 12 different spots. More or less. Think of it like TDMA, if that helps. Switching voltage regulators are super efficient. And even if there isn't an efficiency gain in the VRM, they will likely be one since the processor will be operating at tighter voltage tolerances. The VRM will be closer to the load and be able to react to load shifts quicker, meaning the processor spends less time slightly over-volted. (If the processor needs 1.2 volts or it crashes, an external regulator might have to have a setpoint of 1.3 volts so it never goes under. But that means it wastes a lot of wattage on heat. If it can instead have a 1.225 setpoint, you are saving power that would normally be shed as heat.

Re:Heat

[swalve]

Some of the pentium 4 chips dissipated over 100 watts. I think they know how to move heat off of silicon.

Re:Heat

[viperidaenz]

If you core requires 1V and 90 watts you need to transfer 90A through your PCB traces, up in to the chip, across the bond wires (if there are any) and on to the die.
If your die has a regulator on board and accepts 12V instead, and is 80% efficient you only need to transfer 9.4A. You've just lowered your resistive losses by about 100x. If the connection between the external VRM and die is 0.001ohms, at 90A you waste 8.1W. at 9.4A you waste 0.088W.

Re:Heat

[InvalidError]

The big problem with bringing 12V on-chip is not Ohm's law. It is silicon's breakdown voltage at 22nm.

Trace-to-trace and channel/gate breakdown voltages can be addressed by patterning high-voltage areas with wider insulation gaps but that does not address insulation between metallization layers. It would be feasible but it would also make the fabrication process a fair bit more complex to accommodate the different insulation thickness in the high-voltage area vs the digital stuff.

I'm guessing the ~2.5V happens to be the safe maximum working voltage for Intel's insulation layers. For mobile applications, it would be nice if they brought this up to the 3-4V range so the CPU could be powered right off a single-cell lithium battery instead of requiring a pre-regulator.

If Intel wanted to bring straight 12V into 22nm CPUs, it could most likely be done at the expense of more wasted space around high-voltage vias between MOSFETs and high-voltage layers. I see no obvious reasons why they couldn't do this in future iterations - the extra fraction of a mm^2 it may cost in surface area would likely be easily recovered from eliminating several Vcc/GND pads.

Re:Heat

[fluffy99]

Who said they're going to keep it at 12 volts? A VRM can also be the transformer, but it doesn't have to be. They could ramp down the voltage on the board just like they always did and just have a VRM on the chip that is maintaining a steady voltage. If you read the article they are barging about how little fluctuation they are getting. So it seems like what they are doing here is adding basically an extra regulator on chip so they can have extremely stable voltage. I'm guessing as small as things are getting now, just the trip across the motherboard can have noticeable fluctuations on supply voltages due to EM interference and temp fluctuations, so having a regulator on the chip lets them get more precise. Maybe that precision will let them do some magic on the chip to increase performance or something?

Or they are finding those Chinese made MB motherboards have such poor regulators, that they have to do some final regulation on the die to keep things stable?

This is probably also driven by a desire to start putting higher horsepower CPUs into smaller things like tablets.

Re:Heat

[fluffy99]

The big problem with bringing 12V on-chip is not Ohm's law. It is silicon's breakdown voltage at 22nm.

From the linked PDF - "90 nm technology for test devices". It looks like it's not on the same silicon as the actual processor, but rather stacked on top..

Re:Heat

[fluffy99]

. This in turn means smaller value components required, e.g. the switch from the monster inductors seen on the motherboard (at maybe 1-2MHz switching) in the slide to the tiny chip-scale inductors on the FIVR (at 10's or 100's of MHz).

From the linked pdf - Programmable switching frequency 30MHz to 140MHz

Re:Heat

[allanw]

As an EE, I like to think of Ohm's law as a definition for resistance. The resistance can be non-linear for active devices in which case using V = IR is quite useless.

Re:Heat

[allanw]

So what stops someone from taking the switching frequency really high, like into the hundreds of megahertz? In switching regulators, there is both conduction loss and switching loss. Conduction loss occurs from resistance in the power supply path, including switch resistance. It can be reduced by increasing the switching frequency. However, this increases the switching loss -- you have to switch the power FET gate capacitance more often. The most efficient system is achieved when conduction loss is balanced with switching loss. It is a complex engineering problem. By making a tiny package integrated solution, the inefficiencies of switching can be reduced so the frequency can go up. This cannot be easily done with a traditional discrete-based system like on current motherboards.

Re:Heat

[Virtucon]

And I have a couple of Bulldozer AMDs that run up to 125W that still doesn't mean that you can't cook something or shorten its life. Since these will be 10W processors it will be interesting to see how well they stack up against their predicessors because if they are favorable in comparison then it will be a lot less heat and a lot less noise in desktops.

Re:Heat

[dgatwood]

Intel might be the first to do it on a CPU die, but they're not the first to do on-silicon inductors by any stretch. Switching regulators with inductors on silicon have been commercially available for several years now. The R-78 and MIC33030, for example, are drop-in replacements for linear regulators, with all components on die.

The real question in my mind is why anyone still uses linear regulators for anything, but I digress.

Re:Heat

[SuricouRaven]

That R-78E3.3-0.5 looks useful... the raspberry pi uses a rather inefficient linear regulator to take the 5v input down to 3.3v. An NCP1117. Can't just replace it with an R-78, as the minimum input voltage is 6V, but if you're running it off of something higher... yes. This component may be of use to me.

Re:Heat

[SuricouRaven]

Ohm's law goes out the window as soon as inductance becomes a nontrivial factor.

Re:Heat

[Joce640k]

I have yet to come across a voltage regulator that doesn't run hot. Typically, it's one of the hottest components in an electrical circuit. And we're integrated this into a slab of silicon already well-known for getting so hot it can catch fire?

Gee. If only Intel had some proper engineers like you who could think of clever things like that...

Re:Heat

[AmiMoJo]

Actually the analogue guys like Texas and Linear do make switching regulators with on-board inductors that are pretty small. Small enough that they could be integrated into a typical desktop CPU form factor.

Unfortunately TFA is light on details. 1/50th the size of what? A mains transformer? A SOT-23 IC?

Re:Heat

[Anonymous Coward]

Sorry, but I design quite a lot of switch mode regulators for my own hardware design, and there are several concerns here:
- the efficiency of 76% they claim is abysmally low, my regulators are never below 80% in their operating range, and often above 90%, with peaks in the 96-97% range.
- switch mode regulators need an inductor, and inductors need ferrite or iron cores, which is not going to happen on a silicon die. External inductors are much better
but low loss inductors for large currents are large, for fundamental physical reasons.
- the fastest acheivable switching frequency is in the low tens of MHz, and this is with considerable losses. Lowering the frequency decreases the losses which happen while the swictch(es) change state, which are dominating at higher swictching frequency. At lower switching frequencies, losses are dominated by I2R
in chokes and traces.
- increasing switching frequency allows to increase loop bandwidth and transient response, but another way to improve transient response is to increase output capacitance, which is relatively cheap at low voltage and is best attained by a parallel combination of ceramic capacitors (class II dielectrics like X5R/X7R, never use class III like Z5U or Y5V, they have horrible temperature and voltage dependent characteristics) for high frequency filtering and low ESR tantalum (like
AVX TPS, designed for this task) for absorbing transients while the regulator adapts within the limits of the loop bandwitdh.
- loop bandwidth can never be much above one tenth of the switching frequency, to avoid excessive phase shifting due to the sampling that makes the loop unstable
- an efficient way of minimizing ripples is to have several regulators in parallel with the same clock phase shifted. I've got exceptionnally low ripple in this case
(could not measure it with a good scope, not with a voltmeter whose bandwidth included the switching frequency).
- for the large currents, the regulator will be dierctly connected to a ground plane and to an output voltage plane, voltage drops on plane should be low enough
if you put enough vias to the component (BGA/LGA), and you can always sense the voltage back from the largest consumer.

Re:Heat

[wikdwarlock]

Check out pages 7-9 or so for the magnetics and inductors: http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf

Re:Heat

[wikdwarlock]

Check the next-to-last slide on the linked presentation. 50X smaller than typical VR components usually placed next to the CPU. http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf

Re:Heat

[Anonymous Coward]

I have seen you post on slashdot a lot. You are not a nice person. Perhaps you should work on that.

Re:Heat

[serviscope_minor]

Most likely, because it's integrated into the CPU itself, the voltage regulator can be made more efficiently and thus save power and heat etc. Discrete parts have their limitations, and doing it on-die might just mitigate that.

I'm not sure that follows. For transistors doing computation, the efficiency saving is by reducing the amount of current that they have to switch. In this case, all they're really doing is building a very large MOSFET onto the die itself along with a bit of other gubbins.

Also, the efficiency figures they claim aren't very high compared to other buck regulators. For example, a quality PSU exceeds the efficiency figures they claim.

In fact, using a really tiny process size for power components is no advantage since you start to suffer on things like the short channel effect. As such the process won't provide any advantage since they'd have to fab the power device to be much larger than the process size anyway.

All in all though, they're moving 10W or so from an external power device to an internal one. It's not going to be a huge change either way.

Re:Heat

[serviscope_minor]

But you can do that w/ an external regulator too. Apparently the secret is on-chip inductors. Now that's impressive. I'm surprised that some of the "analog" companies making switchers didn't come up with that first. I know Intel has good fab tech, but this seems more like the sort of funky thing analog guys would come up with first.

They did.

I did a semiconductor course on analog CMOS as an undergrad over 10 years ago. It's interesting because the CMOS processes are typically adapted for digital electronics, and can't give things like BJTs without modification. The radio (phone, wifi, bluetooth) companies want to make analog circuits as cheaply as possible, which means using older gen CMOS to do analog.

Firstly you put down a bunch of metal in a spiral shape to make the inductor. That bit is easy.

Getting the Q up is interesting, because especially on a bulk silicon process there is a lot of stray capacitance.

Due to some weirdness of surface chemistry which is beyond me you can etch preferentially along certain cleavage planes, which means with care you can actually dig under the spiral using careful placement of SiO2 and bare silicon patches.

I doubt intel do that though since there's no need to get such high Q outside of radio receivers.

Can some practicing semiconductor engineer chip in?

Re:Heat

[serviscope_minor]

The control logic could go into the CPU, but I don't see how pulling 12V down to fractions of a volt is going to happen on the die itself without it burning a hole through the board; heatsink or not, you can't escape Ohm's Law.

I think that may be the point: at some point you have to pull 100W down to fractions of a volt (i.e. hundreds of amps). By doing it on die, it is closer to where you want it to be so you don't have the problem of shipping hundreds of amps quite such long distances.

Re:Heat

[thegarbz]

What an absurd statement. Just because a device has non-linear characteristics doesn't mean that V=IR is any less useful.

LEDs are non-linear yet we use V=IR as way to determine the required compliance of a current source, or what resistor you need if you go down the easy voltage source route. Or an example closer to home, the MOSFET may have a non-linear and time changing characteristic while turning on, but the regulator's power efficiency is none the less determined by the I^2R losses. That doesn't change just because R changes with time and voltage.

The only time it becomes useless is when power is radiated out of the circuit as in antenna theory.

Re:Heat

[domatic]

I've heard of light bulbs used as current limiters in speaker stacks. Put something like a motorcycle tailight in series with a bass driver.

Re:Heat

[fnj]

Well even at 10W I'm wondering how they'll address the heat.

Are you serious? Essentially all of the power going into the CPU is coming out of it as heat already. That's 35-100+ watts of heat already being dissipated. And you're worried about another 10 watts?

Re:Heat

[dlcarrol]

I suspect he meant, "Could not measure it with a good scope, nor with a voltmeter ..."

Re:Heat

[fnj]

Perhaps you can explain where you are getting that "10W" figure from. Haswell spans 10W (ULV) to 37W (mobile) to 100+W (desktop). The referenced article has a slide talking about 120A and 400A, which is a far cry from the current that would support only 10W.

Re:Heat

[ebno-10db]

The Micrel data sheet says "internal inductor", not on-chip, and the Micrel web site puts it in the switching module category, so I doubt this is on-chip. Nice small pkg (planar magnetics?) but not the same as on-die. Similarly for the R-78, which is listed as a module.

Re:Heat

[ebno-10db]

People have been building inductors on-die for many years. The trick is getting a high enough inductance (and max current) for a switcher. According to the Intel presentation they have magnetic material on die (Ni80 Fe20 WTF?) which AFAIK is new.

Re:Heat

[ebno-10db]

The discreets (cap and inductor) will be external.

The inductors are on-chip, which is what makes this so interesting.

Re:Heat

[ebno-10db]

You make some good points, but the input voltage is 2.4V, not 12V. No way a semi process like this could take 12V. Also, the caps are external, so there will be some resistive losses with the ripple currents.

Re:Heat

[ebno-10db]

you can't escape Ohm's Law

In all the hoopla about on-die inductors, they forgot to mention the detail about room temperature superconductors.

Re:Heat

[ebno-10db]

If only Intel had some proper engineers like you who could think of clever things like that

If only other companies had engineers like Intel, who never make mistakes.

Re:Heat

[geekoid]

" my experience in electrical engineering says"

and the sentences says you don't have a lot of experience.
It's going to be smaller and use less energy.

Re:Heat

[geekoid]

Gosh, if it's was 2.4V that would be fine, to bad it's not..oh wait, yeah, 2.4 volts, it's right in the pdf, not 12 volts.

"but I don't see how... "
that's because you didn't look.

Re:Heat

[geekoid]

If it could get enough power to power a cordless keyboard, you could make millions.

Re:Heat

[geekoid]

I wouldn't call it very bad. In fact, in some circuits they are useful.

Re:Heat

[geekoid]

right now some EE at intel has read you post and is slapping his forehead. Why didn't we address the heat? of my, oh my.

Re:Heat

[Virtucon]

Interesting, I was going off of this http://www.anandtech.com/show/6248/haswell-at-idf-2012-10w-is-the-new-17w

Re:Heat

[tlhIngan]

I have yet to come across a voltage regulator that doesn't run hot. Typically, it's one of the hottest components in an electrical circuit. And we're integrated this into a slab of silicon already well-known for getting so hot it can catch fire?

Can someone please tell me why this is a good idea, because all of my experience in electrical engineering says that when things heat up, they become more unstable and prone to failure, and the one thing you do not want going critical is your voltage regulator. If that goes, the whole computer catches fire.

Voltage regulators typically run hot because of the pass transistor. In a linear supply, the pass transistor is what dissipates the difference in voltage from input to output. In a switching supply, the pass transistor is the chopper (the one that converts the DC to AC for the transformer or magnetics). Most VRMs in computers are actually cooled just passively - if you look, the tab is soldered to the motherboard and a huge copper plane on the PCB (usually via-stitched to carry heat to the ground or power plane as appropriate).

HOWEVER, there is one thing the on-die VRM has over the on-motherboard one - a heatsink!

The main CPU core has to be cooled anyhow, so the VRM has a very easy access to the heatsink and can thus dissipate the heat much easier.

I would guess one of the reasons for doing it on board is because of the currents and voltages involved - power supply is becoming a big issue when you have multiple voltage rails (Vcore, Vgpu, Vio (x a dozen or so depending on the IO), etc). Each voltage rail requires at least one pin or multiple pins, and even though we have 1100+ pins, it still means the CPU is pin-limited (in ASICs, you can be pin-limited, where what you can stuff onto an IC is limited by the number of pins you can have, or silicon-limited, where what you can stuff in is limited by silicon area. SoCs and such are typically pin-limited, while memories are silicon limited. Similar concept to IO bound and CPU bound programs, really.)

If instead of dedicating easily 100 pins to power (if your core is 1.8V and you're drawing 90W, you're wanting 50A, and each pin may take .75-1A max meaning you're looking at 50-75 pins, plus power to other onboard stuff), you can dedicate 25 to higher voltage single rail, it's a lot less current per pin, so lower IIR losses, and a lot more pins freed up. If you need 90W, and you feed in say, 15V, you only need 6A, so instead of the 50-75 pins to carry 50A, you only need say, 10 pins. Plus, if you want other voltages, instead of dedicating more pins, the onboard VRM gives you more flexibility - say you want another 60W, that's 150W, at 15V, that's 10A, or 10-15 pins. Still a lot less and giving you 80-odd more pins for further I/O.

80 pins is a lot - you can add a number of additional PCIe channels and lanes with that, for example. Or additional functions.

And you've simplified the motherboard design a lot and gotten rid of a potential source of issues - poor power supply design by motherboard manufacturers (applies mostly to cheap budget boards).

Re:Heat

[InvalidError]

While the paper is about a "test device" produced several months ago, Haswell is a shipping 22nm product coming out early next month that already integrates this on-die and calls it FIVR - Fully Integrated Voltage Regulator. If the IVR was stacked die, it would not be quite "[b]Fully[/b] Integrated", wouldn't it?

Stacked die would also have a problem with dissimilar die areas: Haswell itself will be over 140mm^2 while the IVR powering it would only be around 15mm^2. That does not stack very well unless you want to waste over 125mm^2 per 90nm stacked chip. Not to mention all the thermal resistance stacking the VRM on the CPU would add.

If Intel's experimental IVR was intended to remain discrete, they would likely have chosen some higher voltage than 2.4V for the feed voltage since they would not have had to worry about keeping it compatible with their CPU process. I'm betting that they will increase the input voltage it as they refine the design, techniques, process and materials... maybe Broadwell will step it up to 3.3-5V to be more PC-friendly and efficient through reduced input I2R losses.

The main reason Intel used 90nm for their experiment most likely is that 90nm is much cheaper to experiment with than 22nm and high-voltage/high-power electronics does not really care about features below 100nm anyway: at 2.4V, you would need about 100nm insulation between input and ground/low(er)-voltage structures so 90nm has just about the right resolution to provide representative results.

Re:Heat

[jcdr]

Or they are finding those Chinese made MB motherboards have such poor regulators, that they have to do some final regulation on the die to keep things stable?

Mod parent up.

This is a very interesting argument, especially now that chip require multiple voltages with dynamic setting and precise tolerances.

Re:Heat

[nerdbert]

I do SoCs with integrated regulators now.

Their inductors are on-chip using extra thick metal levels. But "extra thick" levels on sub-20nm chips are still pretty damn thin, meaning high r/square, so the Q they can get out of the inductors is pretty low, especially since the configuration they use (linear coupling rather spiral) will also limit their available Q. That's what's driving their efficiencies down from what you're used to in discrete buck regulators.

The big advantage of integrating this is that you don't get the all the nasties of the pads. You usually get the power routed to the corner pins on an SoC and a big chip can easily generate 20+ nH and 1 pF on the pins of a wirebond SoC, and even a flip-chip will still see more than 10 nH typically. That's a problem when trying to deal with power transients, so the on-chip regulator really helps get the ripple down since it can sense/adapt to the voltage at the pin.

Personally, the big eye-opener to me was doing 400A of DC power on chip. Even at sub-1V the electromigration issues they have must be killer.

Re:Heat

[nerdbert]

Discrete buck regulators lose efficiency above roughly 1 MHz due to the parasitics associated with the pass devices and pads. You'll see fully integrated solutions that run at 5 MHz or so if they're meant to supply other chips simply because the parasitics will generally limit the performance to around that frequency. Specialized systems (like the regulators to previous Intel CPUs) can run higher than 5 MHz, but in general the return isn't that good for increasing the frequency.

Putting the regulator on the same chip changes the ball game since the pad parasitics in particular are avoided. There you can run much, much higher in frequency and the Intel guys go up to 167 MHz/phase in their presentation.

Re:Heat

[cellocgw]

I've heard of light bulbs used as current limiters in speaker stacks. Put something like a motorcycle tailight in series with a bass driver.

Cool. Reminds me of the trick some pinball designers used (back in the EM days) to generate a one-shot long pulse, typically to fire off a buzzer. Run the solenoid enable line thru a blinker bulb, so the enable remains active until the bulb warms up. First "blink" and the circuit opens.

Re:Heat

[girlintraining]

What an absurd statement. Just because a device has non-linear characteristics doesn't mean that V=IR is any less useful.

I assume you meant to reply to the GP, not my post. My position is the same as yours...

Re:Heat

[viperidaenz]

Ok, so the factor is only 4x then.

Re:Heat

[thegarbz]

But you don't use it for the LED itselt, you instead pick a current, then figure out what voltage is needed from the spec sheet.

You mean the spec sheet which shows graphs for I against V?

Don't be daft. You do use it directly. It may be time varying for high current pulses but the fundamentals are still the same.

Full presentation

[AdamHaun]

You can find the full slide set in PDF format here.

If I read this right, it really is a fully on-chip switching regulator, inductors and all. They already have a test chip that they used to power a ~90W Xeon E7330 for four hours while it ran Linpack. (Or a virus -- it says Linpack in the summary page.) Voltage ripple is less than 2mV. Peak efficiency per cell looks like ~76% at 8A. They claim hitting 82% would be easy, and there are "additional advancements that cannot be reported at this time" planned for the future.

The slides have bunch of other technical details about testability features, too, which is always neat to see.

Re:Full presentation

[girlintraining]

hey already have a test chip that they used to power a ~90W Xeon E7330 for four hours while it ran Linpack. (Or a virus -- it says Linpack in the summary page.)

Respectable viruses take issue with your comment that Linpack is anything like them. Viruses do useful work.

Re:Full presentation

[ebno-10db]

inductors and all

Now that's impressive, and I suspect the real secret to this. Not to say the semi design is trivial, but without the on-chip inductors you wouldn't have much. They weren't clear about it, but perhaps it means getting rid of the big filter caps, and relying on smaller caps for each regulator. It also explains the fast response time with a bunch of smaller regulators.

Re:Full presentation

[allanw]

An Intel CPU has a TDP of 90W+ running under 1V. That's 100A+ from the switching power supply. With resistive loss, and inefficiencies from multi-phasing the regulators, efficiency are worse than you say. The cost is also high -- having all of this integrated into the package saves on the platform cost.

Re:Full presentation

[allanw]

The term "virus" in this context means a power virus -- which is an artificial workload designed to draw as much power as possible from the chip. For example, normal CPU burn stress tests might only activate 90% of the chip's power consumption, but a specially designed power virus would be able to activate all of it. In some cases designing the thermal and power integrity solution to support the chip's full power consumption under a power virus needlessly adds extra costs to a product, because it will never see that workload in real life. It's a virus because a malicious person might be able to activate this mode and melt down your CPU, so typically they _do_ have to design the system to support it.

Re:Full presentation

[jcdr]

Keep in mind that the Intel solution use a 30MHz to 140MHz switching frequency, compared to the 0.5MHz of the LTM4620.

Re:Full presentation

[ebno-10db]

From a switchmode supply point of view, they are shitty. 75% at 10A

See here for _MUCH_ better parts from their analog competitors http://www.linear.com/product/LTM4620 LTM4620 - Dual 13A or Single 26A DC/DC Module Regulator with integrated magnetics At 10A output, you get close to 90% efficiency and they take 5V or 12V input directly.

Yeah, and the Intel thing will need a double conversion (12V to 2.4V external, then 2.4V to 0.9V? on-chip) so the total efficiency will be even lower. Not an efficiency improvement for the overall system.

Not a bad idea

[EmagGeek]

An on-die power controller still needs to have external capacitors, especially at the power levels we're talking about.

But, the problem areas in a switching supply are EMI and stray inductances on the board slowing down the turnon of the mosfet. Because the turnon is slowed down, the mosfet spends time in the ohmic region, which creates excess heat.

An on-die gate driver routed directly to the gate with no trace length has no stray inductance, and an on-die gate probably also has less capacitance than a discrete component. So, switching times are much much faster, and there is far less loss per cycle in the ohmic region. That's a Good Thing(TM).

EMI will also be reduced just because there aren't a bunch of high speed traces running around, and the thing can run in the multi-MHz range, so less energy is switched per cycle, and maybe even the switch inductor can even be small enough to simply be drawn in silicon.

I would not be surprised to see efficiency in the 95+% range even coming from 12V down to 0.9V or whatever voltage this thing runs at, so you'll be throwing an extra 6W or so into a 120W package. Not bad.

Re:Not a bad idea

[ebno-10db]

even coming from 12V

Way too high of an voltage for these sorts of semi processes. I think it starts at 2.4V.

Re:Not a bad idea

[serbanp]

I would not be surprised to see efficiency in the 95+% range even coming from 12V down to 0.9V or whatever voltage this thing runs at, so you'll be throwing an extra 6W or so into a 120W package. Not bad.

Bollocks! Since the internal VR uses the same process as the CPU itself, it can't sustain high input voltages, therefore a one-stage 12V to 0.9V conversion is just a pipe dream.

The longer pdf presentation actually shows the motherboard-level 12V to 2.2V VR, which would be still rated for the full power (85W plus margin). OTOH, it's quite impressive that the 22nm process has support for 2.2V CMOS.

As others mentioned already, Intel is just trying to solve the power distribution issue, not eliminating the main down-conversion stage, which will *always* be external.

As a CPU VR designer myself, I'm very interested in seeing how this concept will play out. Beside the issues of more peak power dissipation on the CPU die and increased EMI, there is a long-term reliability issue involved, especially on the power stage; switching inductive loads creates ringing, which will degrade in time (through HCI) the switching transistors.

Re:Not a bad idea

[ebno-10db]

switching inductive loads creates ringing, which will degrade in time (through HCI) the switching transistors

What's "HCI"?

Re:Not a bad idea

[ebno-10db]

a one-stage 12V to 0.9V conversion is just a pipe dream. The longer pdf presentation actually shows the motherboard-level 12V to 2.2V VR

Do current CPU VR's do a one-stage jump from 12V to 0.9V? If so it seems they'd have an efficiency advantage by avoiding a double conversion. 12V to 0.9V seems like a big jump for a buck converter, but perhaps there's another way.

Re:Not a bad idea

[serbanp]

Yes they do. Peak efficiency is usually above 90% and these days it depends mostly on the quality of the power switches and inductors, and the switch drivers strength.

There have been computer systems (especially notebooks) that did a double conversion (Vbatt to 5V, then 5V to whatever voltage was needed, CPU, memory etc), but it did not caught on.

There is also the "hidden" double conversion scheme in which the final VRs are powered from the battery, while the charger acts as a first VR,converting the adapter voltage to the battery voltage. Systems with this type of power tree are becoming more popular.

Re:Not a bad idea

[jcdr]

Bollocks! Since the internal VR uses the same process as the CPU itself, it can't sustain high input voltages, therefore a one-stage 12V to 0.9V conversion is just a pipe dream.

The longer pdf presentation actually shows the motherboard-level 12V to 2.2V VR, which would be still rated for the full power (85W plus margin). OTOH, it's quite impressive that the 22nm process has support for 2.2V CMOS.

The actual FIVR don't use the same process as the CPU. It's a separete die using a 90nm process. Read the page 7 of http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf for the details.

Re:Not a bad idea

[ebno-10db]

It says 90nm for test devices. It's not clear how the production device works.

Re:Not a bad idea

[jcdr]

An on-die power controller still needs to have external capacitors, especially at the power levels we're talking about.

From the presentation PDF, the capacitors are builds from the the metal layers of the die.

Re:Not a bad idea

[jcdr]

Intel is just trying to solve the power distribution issue, not eliminating the main down-conversion stage, which will *always* be external.

Maybe the first stage can still be integrated into the package if not in the die. Only putting the transistors into the package will allow them to dissipate in a far better way than is most existing motherboard designs. Some high end server motherboards and some high end GPU cards uses state of the art switching regulators with high frequency, small magnetic and small ceramic capacitors. There small size can possibly make realistic an integration into the package.

Now just stack the SDRAM as planned and enjoy a package with almost only I/O signals...

Re:Yawn

[wbr1]

Apparently your e-peen is already small enough to fit on die.

From a former power supply designer - Neat!

[jimmyswimmy]

That's some amazing work. The current state of the art in CPU power supply designs hasn't changed in 15 years. 12V in, low voltage out, and the output voltage has been moving lower and lower for years, with designs below 1 V. If you figure you had a few percent of tolerance in the early years when everything ran off 2.5V and that few percent remains constant, then at 1 V you have almost no room for slop. So there are a lot of output capacitors there, both those electrolytics (you always hear people complaining about them but they're CHEAP) and ceramics. The ceramics cost a fortune and you need a lot of them to get your tolerance down - the first half microsecond of a load step is entirely the ceramic capacitor's response, not the controller or anything else. Moving part of the VR onboard allows them to reduce the parasitics significantly and they can probably tolerate a little higher tolerance as a result, but moreover they can get rid of some of those ceramics in the whole system - ultimately many of those on the motherboard.

So this is taking a lot of cake out of company mouths. Analog, Intersil, IRF, ON, who else - manufacturers of controllers, MOSFETs. Inductors, ceramic and 'lytic vendors are all going to lose out a bit here. Potentially Intel can reduce the platform cost vs. AMD as well, which is interesting. There is still an onboard VR but it will be 12 - 2.4 V, wherever they think the sweet spot is for efficiency and size. And the first real change in this industry for a long time. Cool work.

Re:From a former power supply designer - Neat!

[gr8_phk]

Where did you see the input voltage for this thing being 2.4V? I was going to ask what it is.

Re:From a former power supply designer - Neat!

[ebno-10db]

http://www.psma.com/sites/default/files/uploads/tech-forums-nanotechnology/resources/400a-fully-integrated-silicon-voltage-regulator.pdf

Re:From a former power supply designer - Neat!

[petermgreen]

Afaict it's not explicitly stated but it's implied by a caption on page 24 of the slides pdf that someone linked above.

Re:From a former power supply designer - Neat!

[allanw]

ARM chips are more like 10W, not 100W like high-performance CPU's. These power supplies are much more complicated to design. This is actually at the leading edge of R&D -- no other chip maker has made a commercial product with integrated voltage regulator in the 100W range. It's only been done in academia recently.

I am totally impressed

[overshoot]

... that they can incorporate the inductor and capacitors for a 90 W switchmode regulator onto silicon. This is a breakthrough in physics, not just in semiconductor processing.

Re:I am totally impressed

[ebno-10db]

This is a breakthrough in physics, not just in semiconductor processing.

What sort of a breakthrough in physics? Have they found a way around Maxwell's equations or something?

Re:I am totally impressed

[jimmyswimmy]

Not such a big breakthrough as you'd think. As you increase the switching frequency you can decrease the value of inductor and capacitors required. Last CPU supply I built - 10 years ago! - used 100 nH inductors at 300 kHz per phase. I skimmed the PSMA article but there was mention of MHz operating speeds, not at all unheard of these days, so the components ought to be much smaller. A 10 nH inductor and some hundreds of pF of capacitance seems very feasible without stretching the bounds of silicon technology at all.

Re:I am totally impressed

[InvalidError]

Nothing new about physics there. It has been known for decades that a piece of wire starts behaving like an inductor at high frequencies and parallel wires or planes behave like capacitors. Both notions have been in use for high-speed analog and RF ICs and PCBs for a long time. For capacitors, there is even a whole class called "Multi-Layer Chip Capacitor" which is basically an IC with several metallization layers connected at alternating ends.

This is simply the somewhat unexpected but logical application of well-known principles to an old problem: making PSUs smaller.

The real breakthrough here is a VRM solution capable of operating reasonably efficiently at 30+MHz with a multi-phase architecture that brings ripple frequency over 500MHz; within the realm of what can be filtered on-chip.

Re:I am totally impressed

[jkflying]

Frequencies of 30 - 140 MHz. And to think that it has only been 20 years since our CPUs weren't even that fast.

Re:I am totally impressed

[serbanp]

*You* are either completely off or are talking about something totally different; the subject is VR for CPUs.

In a buck converter, the inductor's value is computed from the desired current ripple, which usually is a fraction of the TDC value. Although a 100nH inductor is a little extreme for 300kHz switching when vout is about 1V, its certainly doable; you'll get high inductor ripple, crappy efficiency but also fast transient response and such inductor is cheap.

The 100uH inductor at 300kHz is appropriate for a high-voltage converter, with an output voltage of e.g. 400V and requiring very small ripple.

Time to call my broker,

[Fengpost]

and dump my Maxim stock!

Compared to a traditional regulator?

[perpenso]

Being 1/50th the size it will be welcome on mobile devices. Not sure that its a good thing for your gaming desktop.

That 84 watts is going to rip through your mobile device's battery pretty damn fast.

Don't we need to compare it to a traditional regulator implementation before we come to that conclusion? Assuming pretty damn fast means faster than current Atom based devices.

Re:Rotten idea for performance

[Anonymous Coward]

You should contact Intel - I bet they didn't even consider this.

Re:Yawn

[Dachannien]

Seriously? And here I thought I was being clever. I bow to the master.

Re:On-Die die risk?

[eclectro]

I suggest the tag for this story be 'whatcouldpossiblygowrong"

Re:Rotten idea for performance

[0123456]

CPU chips are performance-limited by heat.

My old Pentium-4: 130W
My new i7: 75W

There's plenty of headroom to output a few more watts without having to underclock the chip.

Re:Rotten idea for performance

[allanw]

If they can cut down platform costs by a few tens of dollars then it is a huge win. This solution removes a lot of discrete chips sourced from a lot of outside companies. Current voltage regulators for these 100W chips are multi-phase regulators, which means something like 4 - 12 parallel voltage regulators with their own inductors, etc. Also, the required area is 50x smaller according to their presentation, which directly affects form factor and cost of these systems.

No it's about ripple

[dutchwhizzman]

If you'd read at least the summary, the benefit would be less ripple. Because it takes time to get the feedback voltage to the external VRM, there would always be ripple if power demands would fluctuate fast enough. In a typical CPU on a typical load, you get a lot of power load changes, so you'd get a lot of ripple. Ripple means that ultra low power circuitry will be harder to implement and hit limits earlier, since it is more dependent on precise voltages.

Power saving wouldn't be relevant, if you are looking at the power loss in the circuit board traces to the CPU. The efficiency of the internal regulator is lower than that of external voltage regulators so it would probably consume even more power.

System cost would be higher. Other components on the main board still require regulated voltages, so no components would be saved there.

Re:No it's about ripple

[thegarbz]

System cost would be higher. Other components on the main board still require regulated voltages, so no components would be saved there.

This is actually something you're wrong about. A modern CPU require 3 distinct voltages separate from all other devices on the motherboard. The bus, northbridge, memory, and every other non-cpu component will run at different voltages. About half of the regulators that take up real-estate directly around the CPU serve only the CPU. These components could be saved.

Re:No it's about ripple

[viperidaenz]

Regulator efficiency isn't the whole picture. When you're converting to low voltages and high current there can be significant losses in the PCB traces and chip packaging between the regulator and the die. Moving the regulator closer can minimise these losses.
and like another reply to your post stated, the CPU core voltage isn't shared with any other component.

No significant cost savings

[dutchwhizzman]

There are more components on the main board that need voltages regulated. You may be able to skip some parts for specifically the CPU, but the rest of the main board needs clean voltages too. For all the peripheral chips and the PCI bus, you still need all the rest of the voltage regulators and discrete components to make those work.

No it's not.

[dutchwhizzman]

The heat is one factor in a list of many that limits performance. Others are how precise the voltages are, clock speed, die size and probably more. If you can increase voltage precision and gain more with that than the hit you take with adding the heat, you're still winning overall. Intel clearly got to the point where they could take the heat penalty and still come out winning because of the better voltage regulation.

virus == power virus

[girlinatrainingbra]

re:

The term "virus" in this context means a power virus -- which is an artificial workload designed to draw as much power as possible from the chip. ... ... It's a virus because a malicious person might be able to activate this mode and melt down your CPU, so typically they _do_ have to design the system to support it.

Wow, thanks for the very informative post. It makes sense that being able to deal with full thermal stress would be useful. I've had my quad-core shut down on me once at 20-30 seconds into the boot-up sequence, and then I realized that the heat-sink was not fully applied to or in contact with the CPU surface. I reseated everything and the boot-up sequence went just fine. So I'm really glad that there was an on-die thermal danger detector that shut down my quad-core as the thermal level went to dangerous failure levels. The fact that it's alsodesigned and tested to be actually able to withstand a full power-load draw for a fixed interval is even more impressive.

Here's a link to the wikipedia page about a "Power Virus". And there's an Intel link about "Thermal performance challenges from Silicon to systems" there on the wikipedia page which is a dead link: http://download.intel.com/technology/itj/q32000/pdf/thermal_perf.pdf .

Can they move the CPU away from the die ?!?

[ctrl-alt-canc]

Given the performance of the on-die voltage regulator, the chip could very useful for designing miniature power supplies. Unfortunately the CPU and the associated digital crap ruin what seems to be a very succesful design of an innovative power supply regulator.

Re:Can they move the CPU away from the die ?!?

[MachineShedFred]

It depends.

The initial launch of Haswell will be a 2-chip setup. At this time, it's unclear what that second chip is - perhaps it's the fancy-schmantzy VRM. The one-chip Haswell is due in Q3.

Re:Can they move the CPU away from the die ?!?

[InvalidError]

The second chip in the IVR demonstration is the regulator and is integrated in the Haswell die as FIVR - Fully-Integrated Voltage Regulator.

The second chip seen in some Haswell articles is the 64MB eDRAM for Intel's GT3e IGP.

Re:Yawn

[wbr1]

Couldn't resist. The door to the barn was wide open. No harm intended though.

Re:Big whoop

[EmagGeek]

The need for more performance is also minuscule. Right now there is way too much computer and not enough problem to solve with it. Right now at least it's all about the GPU, which is where almost all computational work is being done. CPUs have become glorified bureaucrats in the shuffling of information around.

Re:Rotten idea for performance

[fnj]

No, unfortunately it doesn't remove any exterior components. The on-CPU regulator is only 2.4-to-1V. The off-CPU regulator just changes from 12-1V to 12-2.4V, but it is still there.

Re:Rotten idea for performance

[InvalidError]

Delivering power at 2.4V is still far more efficient than delivering it at ~1V thanks to significantly reduced I2R and contact losses. While it does not eliminate off-chip pre-regulation, it does eliminate the need for having several regulators for various chip circuits and it reduces the remaining regulator's output requirement from ~100A to ~40A.

So Haswell's FIVR does allow cutting off-chip regulators to less than half or using components with half the current rating, which should save up to maybe $3 on parts. It definitely allows for some savings, just nowhere near Rotten's "tens of dollars."

Re:Rotten idea for performance

[csumpi]

Good catch. I'm pretty sure Intel missed the heat issue. You should call them.

Re:Rotten idea for performance

[jcdr]

Mod parent up.

This will also make the whole system more reliable to cheap off-chip regulators.

What are you all talking about?

[ckatko]

I looked through everyone's comments, hoping to see this important issue and everyone's too busy debating silly shit like heat. When is the end-effect of paradigm shifting ever the same as the issue a company portrays to the public? Did everyone think "Microsoft Open Technologies" was a true attempt at embracing open source software?

Let's look at what's actually going on:

• 1. Overclocking allows for people to buy cheaper processors that do the same thing as more expensive ones.

• 2. Increased voltage is required for overclocking.

• 3. Placing the voltage regulator on the CPU instead of the motherboard removes the control from the motherboard manufacturer and end user.

The end result?

• 4. Overclocking can only be achieved by "official overclocking CPUs" that cost much more.

Intel is working to take away the control people have over their processors. Whether this is the final step, or just a means to an even bigger end, we should be asking more questions.