Power Supply A Guide to 12V PSU

[k0n]

5700 XT Pulse inside a 5L case thanks to 12V:


Got the Pulse and moved. The lid is still missing because I haven't placed the power button yet AND the RAM is a little to high for how I wanted to place the lid :/

 

[DwarfLord]

I am using this one currently with a 3400G with the 120W PicoPSU in a Goodisory/Xpbox A01. With Precision Boost Overdrive enabled I´m getting boosts up to 4.2 Ghz and the highest I´ve seen on my cheap power meter is 106W consumption for the whole system. I´ll still need to do something about cooling this thing, but will post about the build in the Builds section once it´s complete.

Be careful with that. You need to remember that the rating for the picopsu is for all the voltages combined (12+5+3.3v). The 12v rail is only rated for 7A (so 84W), which is real close from what the cpu uses when your power meter gives you 106W for the whole config. Just so you know, I have a 2400G (with no overclock) and I already saw it use 88W during boost.

 

[Thehack]

Be careful with that. You need to remember that the rating for the picopsu is for all the voltages combined (12+5+3.3v). The 12v rail is only rated for 7A (so 84W), which is real close from what the cpu uses when your power meter gives you 106W for the whole config. Just so you know, I have a 2400G (with no overclock) and I already saw it use 88W during boost.

Indeed. The mosfet on those drop voltages pretty early.

@k0n great work! Do you have any problems with the PSU being always on?

 

[grbh]

Be careful with that. You need to remember that the rating for the picopsu is for all the voltages combined (12+5+3.3v). The 12v rail is only rated for 7A (so 84W), which is real close from what the cpu uses when your power meter gives you 106W for the whole config. Just so you know, I have a 2400G (with no overclock) and I already saw it use 88W during boost.

Thanks, I wasn´t paying attention to the rail ratings. I´ve definitely seen instability as soon as I try even the tiniest bit of overclock so that must be the reason. I guess I´m gonna be shopping for a 160W PicoPSU or 200W HDPLEX next.

 

[Thehack]

Thanks, I wasn´t paying attention to the rail ratings. I´ve definitely seen instability as soon as I try even the tiniest bit of overclock so that must be the reason. I guess I´m gonna be shopping for a 160W PicoPSU or 200W HDPLEX next.

The cheap ones have cheap mosfet. They start dropping voltage (and heating up) once they become overwhelmed.

 

[k0n]

Do you have any problems with the PSU being always on?

No. Same as before... But with everything turned off it still pulls 17-18W. My solution to this is to just cut power at the socket (something I did before anyway).

 

[DwarfLord]

Thanks, I wasn´t paying attention to the rail ratings. I´ve definitely seen instability as soon as I try even the tiniest bit of overclock so that must be the reason. I guess I´m gonna be shopping for a 160W PicoPSU or 200W HDPLEX next.

If you want to keep your current picopsu (or as a temporary solution), you can disable the boost in your bios. Your cpu's max consumption will drop about 20W (so you'll be ok on that side), and you will lose only approximately 5% performance-wise (at least that's what I saw on my 2400G when testing it).

 

[BirdofPrey]

So I guess I missed this during CES, but this might be of interest to folks in this thread:
FSP introduces new 12V only PSU

Apparently this is a PSU that will support some "upcoming Intel standard" which uses a 10pin connector with just 12V and 12vsb. I wonder what boards this is for, but it's interesting. Sadly it's the size of a normal ATX PSU it looks like. But this gives me hope that we may finally start to see the end of the dreaded 24pin ATX connector.

Also, I didn't realize FSP made a 330W slim brick that looks a lot nicer than the usual Dell fare, unfortunately it's a 19V or 24V part, not outputting pure 12V like the Meanwells.

The Design guide (ie. the official specification) includes all of the same form factors we already have (and even makes a mention that the physical form factors have not changed at all), so SFX and TFX power supplies are entirely possible, though, even if those weren't part of the official spec, you can bet that someone would do it anyway at some point.

So the only "new" pin in this design is the +12Vsb, otherwise all the other pins already exist on the current 24-pin. Interesting, this might mean that PSUs could be "dual mode" in the future if designed for it, which means traditional PSUs could be compatible with 12VO motherboards, but obviously not the other way around.

I'm not even sure I'd say it's new. Current ATX standard has a +5VSB, so this is more a replacement.
====
I wonder how long it might take for this to take off, though, honestly, I don't see there being THAT huge of barriers to entry. As we saw during the transition from AT to ATX, I can see motherboards and PSUs with both connectors for a while, since they can easily coexist, and it's not a huge hurdle to support both at once, so I don't see as much risk of this remaining an OEM (or extremely niche) thing as most other standards that have come out recently.. ITX will almost certainly be either the first or the last to go with solely the 12V connectors, since there's just not the space to put both that and the existing 24 pin ATX connector. ITX will probably be the last to switch over since there just isn't space for two sets of connectors, so manufacturers would probably be loathe to switch until the standard is firmly entrenched. or they could surprise us all, and someone will release a motherboard with 12 volt only right away making sure PSUs are available to save some board space, but that's a risky move.

 

[ermac318]

I'm not even sure I'd say it's new. Current ATX standard has a +5VSB, so this is more a replacement.

That's why I put new in quotation marks. It's new in that it's a different voltage than before, but it's still the standby pin (just 12v instead of 5v).

I wonder how long it might take for this to take off, though, honestly, I don't see there being THAT huge of barriers to entry. As we saw during the transition from AT to ATX, I can see motherboards and PSUs with both connectors for a while, since they can easily coexist, and it's not a huge hurdle to support both at once, so I don't see as much risk of this remaining an OEM (or extremely niche) thing as most other standards that have come out recently.. ITX will almost certainly be either the first or the last to go with solely the 12V connectors, since there's just not the space to put both that and the existing 24 pin ATX connector. ITX will probably be the last to switch over since there just isn't space for two sets of connectors, so manufacturers would probably be loathe to switch until the standard is firmly entrenched. or they could surprise us all, and someone will release a motherboard with 12 volt only right away making sure PSUs are available to save some board space, but that's a risky move.

As I mentioned, there are already plenty of embedded boards that use specialized connectors and include a breakout connector to allow a 24-pin input on a smaller board. One could see a motherboard include the 10-pin connector with a dongle, and maybe somehow allow for 5Vsb or 12Vsb depending on the PSU input. Since a standard PSU already outputs 12v rails, you already have everything you need to power this hypothetical ATX12VO motherboard. You just don't have the 12Vsb.

 

[BirdofPrey]

Yeah that's the thing. The ONLY thing that prevents a simple passive cable adapter is the standby voltage.
I just don't know what the costs for doubling up on the power traces in the board is vs the cost of making an adapter that can convert 5VDC to 12VDC

Either way, we're not super likely to see the usual situation where different categories of hardware manufacturers are waiting for the other to support a standard first, because their product is pointless otherwise.

 

[Thehack]

Yeah that's the thing. The ONLY thing that prevents a simple passive cable adapter is the standby voltage.
I just don't know what the costs for doubling up on the power traces in the board is vs the cost of making an adapter that can convert 5VDC to 12VDC

Either way, we're not super likely to see the usual situation where different categories of hardware manufacturers are waiting for the other to support a standard first, because their product is pointless otherwise.

Like 25 cents at their quantity. "Power traces" are essentially free, if you mean copper traces. What's expensive is the amount of copper per layer and how many layer you're building with (both engineering and manufacturing cost). But I think you mean VRM/Buck Converter/Components, and not actually traces.

The main thing the new standby voltage is useful is having enough juice for high current charging. Standard USB ports can do 2.5W charging. One of the new feature computers are getting, in particular laptops, is having standby charging 5W-10W. To do that, you need more standby power. Keeping the primary AC-DC on is not good for standby/low consumption, so you just devise a 20-30W secondary AC-DC to make it more efficient.

You can have a simple buck converter, since you need 5V anyways, even for standby charging. Detects voltage > 10V, enable standby charging. <10V, works like standard ATX.

 

[BirdofPrey]

Sorry bit tired not thinking clearly.

When I meant extra traces, I was talking how much additional complexity it might add to have both connectors on the motherboard. So distributing power from two sets of plugs vs a 24pin to 10 pin adapter with a boost converter to raise the 5VSB to 12V. I hadn't considered still taking 5VSB and converting that on the motherboard.

 

[ermac318]

Sorry bit tired not thinking clearly.

When I meant extra traces, I was talking how much additional complexity it might add to have both connectors on the motherboard. So distributing power from two sets of plugs vs a 24pin to 10 pin adapter with a boost converter to raise the 5VSB to 12V. I hadn't considered still taking 5VSB and converting that on the motherboard.

Yeah I think the answer is if you make a motherboard that takes the 10pin with a converter dongle for 24pin ATX, just have the motherboard accept 5Vsb on the pin as well as 12Vsb.

 

[Thehack]

Sorry bit tired not thinking clearly.

When I meant extra traces, I was talking how much additional complexity it might add to have both connectors on the motherboard. So distributing power from two sets of plugs vs a 24pin to 10 pin adapter with a boost converter to raise the 5VSB to 12V. I hadn't considered still taking 5VSB and converting that on the motherboard.

Ah.

There's no point in having two connectors on the motherboard though. It's not a situation anyone would do, at least for ITX boards.

However to answer your question, it's not complex at all since it's just power. You hook A to A, and B to B, and ignore the rest. If it's a low end, but ATX boards they should have plenty of space for it.

For ITX boards, obviously space is a premium. Only makes sense to use a 24 to 10 wire harness.

 

[BirdofPrey]

Ah.

There's no point in having two connectors on the motherboard though. It's not a situation anyone would do, at least for ITX boards.

Not for ITX boards, no. I did already mention that.
ATX and mATX have the space though, and it ensures backwards compatibility,lack of which is the number one killer of new standards. A similar thing happened when ATX was getting started: you had AT boards with both the old AT connectors and the new ATX connectors as well as ATX power supplies that could be configured for AT

 

[ermac318]

Not for ITX boards, no. I did already mention that.
ATX and mATX have the space though, and it ensures backwards compatibility,lack of which is the number one killer of new standards. A similar thing happened when ATX was getting started: you had AT boards with both the old AT connectors and the new ATX connectors as well as ATX power supplies that could be configured for AT

AT to ATX was a much more complicated changed. AT PSUs had no soft power-off, no standby power, they were totally different beasts. The cost (both in dollars and wasted space on a board) to supply both connectors seems silly when you could just supply a dongle.

 

[Shizzel]

Hello, I'm new to this forum and the 12v stuff and would like to ask some questions.
I have a old itx NAS kind of case (chenbro ES34169) that I want to give a new life.
With a picopsu 160xt I want to power the follow components:

Gigabyte B450I Aurus pro
A amd engineering sample Athlon pro (same stepping as consumer 3000g, wanted a pro because of ecc) tdp seems about 25watt
32gb crucial ecc 2666 ram (ecc already checked and working on this cpu)
crucial mx500 m2
Not yet bought (4x 2.5inch hdd)

I want to power this with the epp200. I think this should be able to work without a fan on the epp. What do you think?
I want to install the epp200 in the chenbro 2.5inch slot near the mainboard. Is it safe to mount it on a piece of wood (easy mounting)? Or is there a fire risk? should I do a iron mount (risk of shorting?).

Thanks for your help!

 

[smitty2k1]

Hello, I'm new to this forum and the 12v stuff and would like to ask some questions.
I have a old itx NAS kind of case (chenbro ES34169) that I want to give a new life.
With a picopsu 160xt I want to power the follow components:

Gigabyte B450I Aurus pro
A amd engineering sample Athlon pro (same stepping as consumer 3000g, wanted a pro because of ecc) tdp seems about 25watt
32gb crucial ecc 2666 ram (ecc already checked and working on this cpu)
crucial mx500 m2
Not yet bought (4x 2.5inch hdd)

I want to power this with the epp200. I think this should be able to work without a fan on the epp. What do you think?
I want to install the epp200 in the chenbro 2.5inch slot near the mainboard. Is it safe to mount it on a piece of wood (easy mounting)? Or is there a fire risk? should I do a iron mount (risk of shorting?).

Thanks for your help!

You could attach the meanwell with double sided tape, I'm pretty sure the bottom is insulated. Wood would be fine too, though I'm not sure exactly what you have in mind.

How do you plan on powering the SATA drives? I think the PicoPSU only has a single SATA power connector?

 

[ermac318]

Hello, I'm new to this forum and the 12v stuff and would like to ask some questions.
I have a old itx NAS kind of case (chenbro ES34169) that I want to give a new life.
With a picopsu 160xt I want to power the follow components:

Gigabyte B450I Aurus pro
A amd engineering sample Athlon pro (same stepping as consumer 3000g, wanted a pro because of ecc) tdp seems about 25watt
32gb crucial ecc 2666 ram (ecc already checked and working on this cpu)
crucial mx500 m2
Not yet bought (4x 2.5inch hdd)

I want to power this with the epp200. I think this should be able to work without a fan on the epp. What do you think?
I want to install the epp200 in the chenbro 2.5inch slot near the mainboard. Is it safe to mount it on a piece of wood (easy mounting)? Or is there a fire risk? should I do a iron mount (risk of shorting?).

Thanks for your help!

@smitty2k1 The HDD backplane uses a single Molex connector. You can use a SATA->Molex solid adapter to solve this issue and power the whole drive cage.

I would caution @Shizzel on using the 2.5" drives over 3.5" drives. Most of the power board-style adapters have a lot of 12V but not much 5V. 3.5" HDDs need both voltages to power on, but the majority of power draw comes from 12V, because 12V drives the motor. In a 2.5" drive, all the power is 5V and sometimes the 5V rail on these PSUs isn't so hot. Just make sure you check the spec sheets of your drives and the PSU. Your Meanwell only outputs 12V so you must rely on the stepdown of the ATX Power Board to give you 5V (unless you have a motherboard that does this as well).

Unless you're getting 2.5" SSDs in which case power becomes a non issue, for the most part. Your big issue there is that the backplane is only SATA2 speed (3Gbps) so you're really gimping your throughput.

 

[aquelito]

@Thehack : Hi there, is this the right way to ground the enclosed RPS-400 ?