Custom 19v/12v Flex PSU for thin ITX

[Necere]

So I've been exploring the possibility of doing a case based on thin ITX with GPU support, and as some of you know, one of the sticking points is the power supply situation. Thin ITX only takes 19v, while GPUs need 12v. Problem is, there are no power supplies (AFAIK) that will do both (plus other usual rails - 5v/3.3v) simultaneously. So I've been thinking about approaching FSP or another PSU company to see if we can get made. Power supplies aren't really my area of expertise, so I figure I'd ask some of you guys that have looked into this what you'd want out of such a power supply.

Here's my preliminary wishlist:

• 19v@5-7a: 2-pin connector, suitable for thin ITX (& maybe mini-STX?)
• 12v@18-22a: 6+2 pin PEG, plus additional connector for powered PCIe riser (PEG 6-pin?), SATA power
• 5v/3.3v@?a (+other rails?): SATA power
• Total power: 350-400W
• Gold+ efficiency rating
• Flex ATX form factor: 40.5x81.5x150mm
• 40mm fan, optimized for low noise

If anyone would be interested in something like this, or can help fill in the blanks, provide feedback etc., please do.

 

[CC Ricers]

The main issue I see many people have with getting the most out of thin ITX builds is the power situation with discrete graphics cards. These boards usually just have a 1x or 4x PCIe slot at the most.

So a PSU that can also make it more intuitive to route power delivery for graphics cards would help a lot. For thin ITX, currently you have to hack a solution with multiple PSUs or create a small custom board.

 

[jeshikat]

@ilovelampshade is working with HDPLEX to create a custom DC-DC board that takes 19V (at least, it may be wide input like the normal HDPLEX units) and outputs the normal 12V, 5V, and 3.3V but has a pass-through connector for Mini-STX, Thin ITX, etc.

It'd still require a AC adapter though.

 

[Necere]

The main issue I see many people have with getting the most out of thin ITX builds is the power situation with discrete graphics cards. These boards usually just have a 1x or 4x PCIe slot at the most.

So a PSU that can also make it more intuitive to route power delivery for graphics cards would help a lot. For thin ITX, currently you have to hack a solution with multiple PSUs or create a small custom board.

Yeah, thin ITX boards top out at PCIe x4, but I don't see that as being a big deal. PCIe x4 (at 3.0 speeds) has virtually no performance penalty vs. x8/x16.

The bigger issue is that it's only provisioned for 25W to the slot on thin ITX (vs. 75W for x16), which means an independently-powered riser is practically mandatory.

@ilovelampshade is working with HDPLEX to create a custom DC-DC board that takes 19V (at least, it may be wide input like the normal HDPLEX units) and outputs the normal 12V, 5V, and 3.3V but has a pass-through connector for Mini-STX, Thin ITX, etc.

It'd still require a AC adapter though.

An AC adapter is what I want to avoid, both because it's awkward, and because it puts a fairly low ceiling on power draw. Getting it all together in a single flexATX unit seems more ideal to me.

 

[jeshikat]

HDPLEX makes internal adapters but they only go up to 250W (which should release soon).

I take it the mATX/ATX project is on hold?

 

[Kmpkt]

Yeah I'm working on a board with Larry at HDPlex that would allow you to use either his 160W or 300W internal AC-DC or alternatively an external adapter to power 19V boards as well as 12V GPUs and SATA. If you'd like to discuss the project further shoot me a PM as I'd be keen to get more people involved so I don't have to eat the cost entirely on my own.

 

[Ceros_X]

@iFreilicht

 

[Necere]

I take it the mATX/ATX project is on hold?

Yeah, been that way for a while actually. Cost of shipping is a dealbreaker on a larger case, but if we can get to higher volumes (i.e., with additional products) we'll be in a better position to keep it under control. So smaller designs have taken priority for now. A thin-ITX case is something I'm looking into, but it's still in the early stages, and I have another project that's further along which will probably be released first.

Yeah I'm working on a board with Larry at HDPlex that would allow you to use either his 160W or 300W internal AC-DC or alternatively an external adapter to power 19V boards as well as 12V GPUs and SATA. If you'd like to discuss the project further shoot me a PM as I'd be keen to get more people involved so I don't have to eat the cost entirely on my own.

The AC-DC half is still only 250W though, yeah? While I guess that's doable, it still feels a little tight for a more performance-oriented system with a higher-end GPU. Also I don't love the idea of separates (AC-DC and DC-DC boards). While I can appreciate the layout versatility it affords, I think I still would prefer the simplicity (from the user's perspective) of a combined unit. Also I'm a believer in forced airflow; a little can go a long way.

I suppose it doesn't fit in with your or HDPlex's current projects/products, but have you guys considered a combined unit in standard flex casing, like I outline the OP?

 

[jeshikat]

it still feels a little tight for a more performance-oriented system with a higher-end GPU.

Then again, how much market is there for a high-end gaming system that utilizes Thin ITX? Because the motherboard selection shrinks drastically and then you have the PCIe x4 limit. Which is not really that much of a limit in the real-world but there's the issue of user perception.

 

[Necere]

Then again, how much market is there for a high-end gaming system that utilizes Thin ITX? Because the motherboard selection shrinks drastically and then you have the PCIe x4 limit. Which is not really that much of a limit in the real-world but there's the issue of user perception.

That's true. The main reason I'm looking at thin ITX at all, despite its shortcomings, is that it allows me to knock quite a lot off the volume while still meeting my other requirements (for airflow and dust filtration). The fixed socket location and Intel's standardized cooler design go a long way toward allowing the design to be space-optimized in a way that regular mini-ITX doesn't, since there's less concern about variation in components. On the other hand, the intel cooler is about the size of a 1U cooler, which is going to put a pretty strict upper limit on the kind of performance we could expect from the CPU. At the end of the day, not sure it's worth it.

Then again, looking at for example the DAN A4, the CPU coolers that will fit in that are fairly comparable in size to the intel thin ITX cooler. Personally, I think the CPU cooler limitation there is a bit too strict, and will hold back its potential. For thin ITX, though, it might actually make more sense.

 

[jeshikat]

I'm sure you'd come up with a great design but it's definitely a much more niche design than the M1 which has pretty universal appeal among SFF enthusiast other than the price.

Especially on /r/sffpc I notice the default answer to "what case should I get?" is "Get the M1, if you can't afford it scour /r/hardwareswap or eBay and get it used."

 

[Necere]

I'm sure you'd come up with a great design but it's definitely a much more niche design than the M1 which has pretty universal appeal among SFF enthusiast other than the price.

Especially on /r/sffpc I notice the default answer to "what case should I get?" is "Get the M1, if you can't afford it scour /r/hardwareswap or eBay and get it used."

Lol, true. There's some things about the M1 that I'm not totally happy with, though, which are what I'm trying to address with the projects I'm working on now. I guess the irony of that is they won't necessarily be more appealing to people than the the M1 is - there's not going to be to room for bigger radiators or taller GPUs in the same volume, or something. But I also think to some people they will be more appealing than the M1 is. The balance of features and capabilities will be different, and between the various cases I have planned, from ITX to mATX, they should cover a variety of different needs, and mostly won't be very niche products. It's mainly this thin ITX case that's really niche, and only because I'm trying to get well under 10 liters with it.

 

[jeshikat]

It's mainly this thin ITX case that's really niche, and only because I'm trying to get well under 10 liters with it.

Yeah, it may be too niche to get enough orders for a custom PSU. Because that's a whole extra rail so they can't just tweak an existing design. Then certification is going to cost $10k+ I believe.

 

[Necere]

Yeah, it may be too niche to get enough orders for a custom PSU. Because that's a whole extra rail so they can't just tweak an existing design. Then certification is going to cost $10k+ I believe.

That's partly why I wanted to see if anyone else would be interested. As it stands there aren't any good solutions for powering a thin ITX + GPU build.

Do these new HDPlex power supplies need to be certified as well?

 

[jeshikat]

I'm not sure if the custom one will be.

 

[Ceros_X]

I think there is always a significant segment of the computing population who want to go smaller, or as small as possible. To be honest, I have never really been interested in the M1 or DAN A4 because they aren't portable enough for me - I want something that will fit in a briefcase. I think if you build it, they will come if it is thin-itx setup that supports discrete GPUs. I just think the technical challenges will be significant and you'll have to make it possible for the average and below average user to use it. If I remember correctly, you have to cut the power trace on the MB for fear of pulling too much power through the PCI-E slot or do a custom PCB (ala @QinX's build). If you could package a case with the accessories to make it possible to the entry level user I'm sure it would sell.

For the PSU stuff, couldn't you look into the FlexATX PSU that @iFreilicht was working on and then work for a stepdown from 24v to 19v? I think converting voltage from an existing PSU would be simpler than having a new PSU made, certified, etc.

 

[BirdofPrey]

The bigger issue is that it's only provisioned for 25W to the slot on thin ITX (vs. 75W for x16), which means an independently-powered riser is practically mandatory.

You should page @QinX about that. He did a Thin-Mini ITX project a year or so ago where he made a custom riser to handle slot power for the GPU.

On another note. A Flex ATX PSU that can output 19V would be a neat thing to have, though it is going to be extremely niche. Aside from that, though, I think there are a couple Thin-Mini-ITX boards that accept both 19VDC and 12VDC, though the Thin Mini-ITX IS rather slim at the moment.

 

[Kmpkt]

With respect to the DC-DC solution I am planning with Larry, I am also in talks with other companies including FinSix about possible alternatives for the AC-DC portion of the equation. They've indicated that they are planning some higher wattage application of their GaN based AC-DC solutions in Q2 to Q3 2017. My contact estimated that they could shrink the size of the AC-DC portion of the equation by about 75% which means that if they can actually produce, we could be looking at something nearly half the size of Flex ATX with at least as much oomph, DC-DC board based modularity and significantly higher efficiency as GaN AC-DC conversion runs between around 94-99% depending on the input voltage etc.

 

[R3venger]

@ilovelampshade is working with HDPLEX to create a custom DC-DC board that takes 19V (at least, it may be wide input like the normal HDPLEX units) and outputs the normal 12V, 5V, and 3.3V but has a pass-through connector for Mini-STX, Thin ITX, etc.

It'd still require a AC adapter though.

That sounds really cool, but with such a psu, you need to get rid of the 24 pin.
In such a build, its not necesarry. You would only need a
-19V input
-2-4 Power input connector
-8 pin connector for graphics card
-maybe a sata connector
-and the keyfeature, a switch to power on the psu, when the stx or thin itx board is started.

 

[iFreilicht]

So this is certainly an interesting idea, and FSP does have one or more PSUs with 12+<insert obscure voltage here> for PoE, but those have relatively low efficiency. AFAIK, they're not working on anything better in that field either, but it wouldn't hurt to ask. Maybe one of their designs can be modified relatively easily to output 19V instead of 53V on one rail.

I think the specs you listed are fine and 150mm is a must, but first, you should get the highest voltage you possibly can and for the highest efficiency as well. 40mm fans get loud, even in good PSUs like the SSP300 and the FSP400 (which are both 80+ Gold). The first quiet Flex PSU I ever used was the FSP500-50FSPT, apart from one that I fitted an 80mm fan to, so that is a very huge issue to overcome.

And second, consider that you might as well let FSP design a completely custom PSU (including form factor) if it's just for one case. The biggest issue, as others have said, would be to get enough orders for your case/the standalone PSU to fulfil FSPs MOQ for a custom design. I reckon that might be a bit higher than the 300 they ask for modified designs. Your best bet would be to make a case like this for a big retailer that sells pre-built systems to get the MOQ going an then sell leftovers to enthusiasts. Problem there is that you'd have to invest an awful lot of money up-front.