Which caps to use in ATX Power Supplies?

[BadMan]

So as the title says: Which caps to use in ATX Power Supplies?

We are a ATX Power Supply manufacturer about to launch a new series of silent hi-end Power Supplies, so we are looking on inputs on which brand and model capacitors to use in order to get the perfect mix between quality/performance and price.

So, from spending time on this forum the obvious choice would of course always be to use japanese hi-end capacitor brands - However surprisingly enough most consumers does not even know what a capacitor is and most probably will not pay extra to get japanese caps.

Secondly our experience is that some capacitor brands migth be good enough for some type of products and quite bad for other types. We have seen capacitors working for 7-10 years in PSU's and fail in motherboards after 1-2 years, and also vice versa. So the most expensive choice is not always the best choice.

Our PSU's are hi-end silent PSU's with REAL performance (not fake rated). They are to be considered very good value. We aim to make similar and/or better quality than the biggest brands, but try to keep our selling prices a bit lower. So keep this into consideration!

In general you speak quite good of Samxon in this forum, but we actually do not see much experience/documentation in these. So is it just due to the commercial interest in this brand on this forum

If Samxons are not that commonly used in applications compared to other big brands, obviously there will not be many bad reports. But that does not neccesarly make them better

So, looking forward for your inputs....

[starfury1]

Re: Which caps to use in ATX Power Supplies?

OK I'll bite

You have basically but it in a nut shell
"price of manufacture, quality of components verses a reasonable selling price against other manufactures.

The other factor is the design quality of the circuit.

I suppose it really depends on whom your aiming at selling to.

Some, what are considered crap caps like teapo in a better quality unit can last a long time although still considered crap caps.
(this maybe in part really to the correct selection of the teapo series used in the psu)

I myself also think (and no design engineer here) that the cap selection does become part of the over all circuit quality, of its function anyway.
well the circuit is somewhat optimized against the caps that are used I think...but no guru here
so that is a point I think to be taken into consideration from a design level.

Seems non-aqueous electrolyte are the recommended route for PSU use due to there better heat handling ability
Panasonic FC for example, as opposed to the FM's which are better spec but are an aqueous based electrolyte

Yep Jap caps of quality are the go, but having said that its down to buying power and the price you can get them for in quantity.
(cost per unit)
my choice would be UCC but not cheap

Yes there are enough posts on that to get a good idea as you seem to have

How well a supply can get rid of heat is an important factor in how long the caps may last
since you are aiming for silent this is going to be part of the problem.
So getting good air flow is a must I suppose
(this also is apparently why some of the so called crap caps may last a bit better in a more quality unit)

Samxons, to some extend the jury is still out on but they are looking at being a cheap somewhat quality alternative.
(lest wise the series's talked about here)
(not sure whats possibly recommended for psu use..ask Big pope)

I would take a good look at what they have to offer, get some for testing
and abuse the hell out of them.

Another factor that would come into play I suppose is how long this standard will be around.
(have no idea on this)

I think any supply should be able to give 5 years or more service reliably when used with in specs, Ideally they would last till you ditch them but ok this is the real world.

the other side is marketing and the reputation that is gained by the product you sell
Me I still think word of mouth is the best advertising money "cant" buy.
(although marketing has even cottoned on to that now by giving people free goods to blab about how great something is)

Not that I know much really on supplies and there are others far better at this them me around here to answer this question.

But if it was me Id possibly start with a good stable topology thats well protected etc and them possibly offer it in a lower grade "run of the mill" application and a higher grade build for the power user versions.

If the design circuit quality is there in the lower grade,
well those in the know would probably upgrade it so you still get sales...

The down side is that most people as you say,
don't have a clue and only care how much its going to cost them...unfortunately these people are in the majority.

They will buy any POS a computer shop will sell them for $20 bucks.

Supply a quality product, honor any warranty quickly. should put a company in good stead with the masses.

I guess its a fine line a lot of companies walk in a lot of directions and getting the balance right is a difficult thing.

Well thats may uneducated thoughts on it.

Me I'am happy with my Corsair HX620W not so happy with the Liberty due to the wild card factor of the possible Zup bang

I dont mined spending money a "Quality product"
but I am probably in the minority

HTH

Cheers

[Super Nade]

Re: Which caps to use in ATX Power Supplies?

I expect these caps on a PSU with APFC:

Primary: Hitachi, Nippon-Chemicon, Matsushita, Rubycon
Secondary: United Chemicon, Rubycon

You have to pick the right series though. You cannot assume that what is reliable on motherboards will work great on PSU's or vice versa. CPU VRM design is completely different from the requirements of SMPS design. There is no one-size fits all. However, the Nipponse brands I mentioned are reliable, proven and have a wide variety of selections tailored for specific applications.

Can't say the same for Fujhhyu or Chissi.

[acstech]

Re: Which caps to use in ATX Power Supplies?

I've had good luck with Panasonic FC or FM series. Highly recommended. I'd even say if it fits with the design the NHG series would be fine. Just make sure everything is 105c rated. Official recommendation is Panasonic FC, and their larger types (TS series) for the input caps.

I've also seen many Teapo caps fail in Dell PSU's. So that's one I'd take off the list right now.

Make a PSU with all Panasonic caps, with good cooling and good protections, and I'll be the first in line. Dont skimp on parts selection for the lower end models either; to build a good reputation every PSU you build must have quality parts in it. Dont get greedy, price it reasonably, and you'll sell a load of 'em.

If you can offer me a high quality PSU that isn't overpriced, I'll be there buying.

Edit: Here's how it works. One of these people who doesn't care what capacitors are in their PSU calls the local computer guy when things stop working. He inspects, and tells the customer why the problem occured (blown capacitor). Then, the name of that PSU manufacturer is mud. Not only to the customer, but to the computer guy, and the at least 30 other people he's going to tell. So it pays to use good capacitors.

[starfury1]

Re: Which caps to use in ATX Power Supplies?

BTW
By "lower grade" I didn't mean rubbish either just not top shelf stuff

If you can offer me a high quality PSU that isn't overpriced, I'll be there buying.

I agree and guess thats the hard part.

PSU's of "Quality" here in Aust are not cheap and i'd say like me people think long and hard on spending $200 Plus AU (unless they got money to burn)

Panasonic FC would be the better choice from what I gather round here of the 2 series's

Yes the right cap for the right situation.
(which is really the question your asking)

The hard part for you maybe getting "long endurance/ life time" cap that can handle the heat since by the sounds of it you are wanting to keep them as quite as possible.
I understand that a larger can size might help achieve a longer useful life from therm
(instead of the more used skinny can size) but that I suppose depends on if you are designing from the ground up and can accommodate this into the size box.
(seems they all use the skinny cans, exactly why I don't know. Is it just purely PCB real estate or possibly better airflow?)

I suppose another hard part is getting a physical stable layout that allows good air flow

Anyway should be an interesting exercise...learn by the mistakes the others have made and you will find plenty of posts on them here.

I think if you can supply a quality product at a good price they will beat a path to your door.

And make sure you send one to JG's for review

Cheers

[gonzo0815]

Re: Which caps to use in ATX Power Supplies?

I am not quite sure, if it pays out to be honest these days. I might depend on the marketing mix, if people get aware of such issues.

From the engineering point of view, i think it all depends on the PSU design, what caps can deliver a sufficient endurance.

Depending on cooling, airflow, ripple current, endurance of the cap series and acceptable noise level it is not that hard to choose the appropriate cap series and manufacturer.
I think you should read a few data sheets and the overall guidelines of the cap manufacturers, to get the details.

It is obvious, that a board VRM does need other cps then a ATX psu.

Personally, i only accept one of the Japanese brands, even if they are produced in other countries.
The Samxons are used in some entertaining products, and are successfully used from many forum members here. Personally i would accept them too.
But sure, you have to do your on testing to assure the endurance inb your own products.