Power supplies with solid electrolytic caps?

[japlytic]

I have seen Gigabyte board advertisements with solid electrolytic capacitors, claiming a life of 6 times of conventional units.
So I am wondering if there are any power supplies which use solid electrolytic capacitors (most likely to be in servers and supercomputers).

[gonzo0815]

Re: Power supplies with solid electrolytic caps?

This does not make mutch sense, as usually high quality elektrolytic caps will last a very long time.
The only place, where there could be an benefit would be the smaler caps in an PSU. Unfortunately, those small caps have in most psu`s to be 25v or 50v rated, wich is not the range, where polymer caps are playing very well.

The main benefit of polymer caps are small volume, high temperature and very very high ripple current capability.
This isn`t needed in most ATX psu`s, as there is enough cooling and not mutch ripple current.

Even on mainboards, there wouldn`t be necesarie, but it makes the desing more easy.
E.g. at most newer Gigabyte LGA775 boards, they placed the caps directly between the hot mosfets. They are geting very hot (it makes no fun to touch them...) so with this desing, elektrolytic caps would not be a good choice.
Saidly, on some of those boards they are using those blue solid polymer caps, i du not know, if theyr comparable good as the Oscons.
May be this will be the next badcaps story....

Very small PSu`s like those for laptops and TFT`s are sometimes equiped with polymer caps, as cooling is not that easy w/o fan.

[willawake]

Re: Power supplies with solid electrolytic caps?

i havent seen server psu with polymer caps. usually server psus are cooled very nicely also.

In the high uf values (over 1500) the polymer caps are not as good esr as the electrolytics i believe.

the blue/silver polymer are usually chemicon PSA. The problem with polymer is that we will not see visual failures, just increased esr due to moisture during production or shorts or open. this will be difficult to support unless the user has esr meter, multimeter. still i think we are ok so far.

[PeteS in CA]

Re: Power supplies with solid electrolytic caps?

Polymer types are pricey, so I wouldn't expect them to be used in basic good quality PC P/Ss. As willa pointed out, you usually don't get a visual indication of failure. I don't know how this agrees with experience of folks here, but the tech rep for "a major capacitor manufacturer", , told our components group that the usual failure mode for polymer caps rated <10V is open-circuit, while for >10V it's short-circuit. I'm not sure how desirable it would be for the O/P caps on 12V O/Ps to fail short. Current manufacturing techniques limit can heights and the C-V value range.

[gonzo0815]

Re: Power supplies with solid electrolytic caps?

ok, open or short, at least it is a significant change, so it should be not that hard to check for. But from this point of view, i would be better to stay off thos all solid polymer boards, as obviousely the 12v paths have to be equiped with the 16v parts....
As VRM o/P i would say theyr fine from my point of view.

One thing wich makes me skeptical, is that those PSA polymer caps only stated a endurance of 2000h @105°C
Why are polymer caps in any way limited in endurance and why that low?
So if i do combine this and the fact, that theyr running pretty hot on most of those boards, i am not convinced abouth the lonevity of them.

I would prefer Oscon in any case, as they have very high endurance.

[willawake]

Re: Power supplies with solid electrolytic caps?

sanyo quote a 10 times increase in lifetime for a 20deg reduction in operating temp compared to 4 times for wet electrolytics

polymer performance is not affected by temperature apparently.

[japlytic]

Re: Power supplies with solid electrolytic caps?

I forgot to mention "brick" power supplies, which can get rather hot (especially in the 100W+ range).

[gonzo0815]

Re: Power supplies with solid electrolytic caps?

Well most quality brick pSU´s do already have some solidpolymers, as longas the voltage is not too high.

[PeteS in CA]

Re: Power supplies with solid electrolytic caps?

Vicor's VI-200 series used tantalum O/P caps. Not sure about their more recent series.