
A 189 Year Old Limitation on Inductor Size Has Been Broken (2018) - AHappyCamper
https://medium.com/starts-with-a-bang/the-last-barrier-to-ultra-miniaturized-electronics-is-broken-thanks-to-a-new-type-of-inductor-eb5c1a2c7460
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wbraun
The medium article links to a nature article which explains in depth:
[https://www.nature.com/articles/s41928-017-0010-z](https://www.nature.com/articles/s41928-017-0010-z)

This seems like an interesting development, but the performance gain appears
to be limited to low value inductors in the 10's of GHz range. Those inductors
are already very small and easily integrated on RF ICs.

If you want to miniaturize electronics you need to miniaturize the inductors
used in power conversion, which typically operate in the KHz to low MHz range.
It's a very different problem.

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tgflynn
> If you want to miniaturize electronics you need to miniaturize the inductors
> used in power conversion

Hasn't that problem mostly been solved already with switch mode power supplies
that are pretty small.

With most personal electronics being battery powered these days I'm curious
where you see a real need for further reduction in the size of power
converters. In other words what technologies or devices are currently limited
by the size of their power converters ?

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as-j
> Hasn't that problem mostly been solved already with switch mode power
> supplies that are pretty small.

I waste a ton of board space with power supplies. Not everything is personal
electronics with custom ICs* in the volume of an iPhone. So this means on my
current design there's power supplies for 1v, 1v8, 2v5, 3v3, ~4v, 5v. Each of
these the biggest component is the inductor.

I've sometimes joked, I make power supplies with a computer attached.

Edit: since the volume is low we use off the shelf parts which means we tend
to end up with a variety of voltage requirements. And yes...reduction of rails
is something that's part of components selection, alas....

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tgflynn
Are all of those drawing significant current though ? If you just have some
small component with an odd voltage requirement that doesn't need much current
couldn't you supply it with something a lot simpler than a dc-dc converter,
like maybe a voltage divider or linear regulator ?

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mlyle
Almost certainly not a voltage divider. Maybe a linear, if efficiency doesn't
matter.

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ineedasername
It's definitely a great development, but I don't understand the "trillion
dollar" comment at the beginning. Near as I can tell, inductors are about a
$4-5 billion dollar market [0]

I know it will help miniaturization, but it seems like devices most desirable
for miniaturization are already most limited by other conditions like the
battery in smart phones and laptops. Larger inductors seem to appear mostly in
things like power supplies-- sure we'd like smaller power bricks, but I don't
understand how it translates to trillions of dollars.

[0][https://www.marketsandmarkets.com/Market-Reports/inductor-
ma...](https://www.marketsandmarkets.com/Market-Reports/inductor-
market-212700102.html)

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ncmncm
This will be a bigger deal when they get better effective carrier mass. It
reads like intercalating more boron, or maybe a better choice or mix of
elements, will yield increasingly better results. 50% is a big enough initial
effect to be very encouraging. It is not clear from the article if there is
any theoretical upper limit.

In the meantime, making the biggest part of a circuit 33% smaller might make
the whole circuit almost that much smaller.

The value of these things is greatest manipulating signals at very high
frequencies, far out of reach of digital signal processing. It is probably not
notably useful for power conversion, where the exchange of energy via actual
magnetic fields is what does the useful work.

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dogber1
So many hyperbolic claims that boil down to a moderate 33% area benefit with
very little data about mundane things like long-term reliability, or process
variation.

Every time an article mentions some buzzword like 'graphene', it turns out to
be just a load of baloney. Graphene can do everything but leave the lab.

~~~
Qwertious
Graphene already has left the lab, it's being used in some high-end batteries.

~~~
ineedasername
I think graphene gets a bad rap because it's had a very slow ramp up time due
to chicken/egg problems in production cost/demand curves, but that's been
changing drastically over the last decade. It's come down in cost by multiple
orders of magnitude [0] While total sales have been modestly increasing, with
projections for massive growth [1] and if there's a steady market cap while
marginal costs decrease that much, also means orders of magnitude increases in
shipped product.

It's had a lot of growing pains, but we seem to mostly have passed the
inflection point in terms of market viability.

[0] [https://www.researchgate.net/figure/Fig-12-Comparison-of-
the...](https://www.researchgate.net/figure/Fig-12-Comparison-of-the-quality-
and-cost-of-graphene-products-manufactured-by_fig6_337018282)

[1] [https://www.grandviewresearch.com/industry-
analysis/graphene...](https://www.grandviewresearch.com/industry-
analysis/graphene-industry)

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neonate
[https://archive.is/SKK4v](https://archive.is/SKK4v)

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TimMurnaghan
Does this give a better space saving than a gyrator?
[https://www.sites.google.com/site/roelarits/home/gyrator](https://www.sites.google.com/site/roelarits/home/gyrator)

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tyingq
It mentions 50 percent greater inductance than a a regular coil. Which is
great, but would only reduce the size by a third.

I imagine this has some use cases that would merit the higher cost (graphene
is expensive, right?). But probably not many.

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andrewjrhill
To be fair - a 33% reduction in size is massive for something that has
remained largely unchanged for the better part of 2 centuries.

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topspin
20-30 years really. The introduction of chip inductors, the last really
significant reduction in size for commodity discrete inductors, happened in
the 90s.

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neurostimulant
Whenever there is a new hyped tech, it's always using graphene. But how close
are we to actually deploying graphene-based components to mass market?

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im3w1l
What's the big picture here? What are the uses for smaller inductors?

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myself248
At the frequencies relevant to the present invention, mostly RF front-ends.
Wireless cards, cellphones, radars, etc.

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im3w1l
And it will make the devices smaller? Cheaper? Higher performance?

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topspin
Some of all. Inductors are particularly difficult to accommodate in
contemporary circuits, so a general reduction in size could have an outsized
impact.

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djmips
(2018)

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amelius
What is the typical series resistance of this device?

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haywirez
2018

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xupybd
What medium is paid access now? Do they pay the content creators?

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tyingq
Well, it's a register wall, not a pay wall. Agree it's annoying. The real
annoying part to me is that Google seems to treat it the same as freely
available no-registration content.

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dsego
There is a monthly quota for free access I believe.

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kevin_thibedeau
Just block their JS. It is still readable unlike many publishers insisting
their site runs like a SPA.

