G-Unique Plug&Play DC-ATX Oversea Edition Preview
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24VDC isn't really a voltage that's used.
As mentioned 19V is common for power bricks due to its use in laptops because it's an optimal voltage for lithium Ion batteries.
20V is used for a variety of power delivery standards, most notably the USB power delivery standard (which, while not a part of either the USB 3.1 or USB type C standards, was released at the same time, and is actually where the type C alt mode provisions are laid out)
Again, for desktop PCs, 12VDC is the most used voltage (by wattage)
As mentioned 19V is common for power bricks due to its use in laptops because it's an optimal voltage for lithium Ion batteries.
20V is used for a variety of power delivery standards, most notably the USB power delivery standard (which, while not a part of either the USB 3.1 or USB type C standards, was released at the same time, and is actually where the type C alt mode provisions are laid out)
Again, for desktop PCs, 12VDC is the most used voltage (by wattage)
Keep in mind that a DC-DC voltage conversion is actually two conversions: DC-AC and then AC-DC.
I read this thread through and the previous, but I am still a bit confused about the product. Is this a correct assumption:
The G Unique Plug And Play is a picoPSU sized PSU that is only limited in power by the power brick? Plug and play...good to go...like an ordinary PicoPsu?
The G Unique Plug And Play is a picoPSU sized PSU that is only limited in power by the power brick? Plug and play...good to go...like an ordinary PicoPsu?
Yes. However, we need to stop using the term PICO PSU because:
1)it connotates a line of products from minibox.
2)It is not an actual PSU, power supply unit. PSU would convert AC to DC for components to use. This just regulates DC-DC.
I use the term plugin DC board or PDCB for short, which is vendor neutral and accurately describes the product.
The power is limited by design choice by G-Unique as well. Currently, I believe this one uses a load switch design, which blocks the 12V from reaching your components until you tell the board logic to "turn on the PSU." My current opinion is this is uncessary, as the motherboard themselves already use their own "turn on" logic since they all have their own regulators. There are other design that limits the maximum power you can use. However, it is still a good safe design. G-unique rates his plug&play PDCB for up to 400W, but that's the maximum theoretical power. You also have to take account how you wire the 12V and hook up PCIe, soldering, etc.
TLDR: So for all intents and purpose, since most power bricks don't go above 400W, how much power you can use is up to your power brick.
So I did some rough calculations regarding efficiency and heat dissipation.
Efficiency Specs
DC-DC efficiency assumptions:
AC-DC efficiency figures w/ 115V AC input:
======================================================
350W Load Calculations
DC-DC efficiency calculations:
AC-DC efficiency calculations from above:
AC-DC to DC-DC amperage:
======================================================
350W Load Efficiency
AC draw at the wall:
Overall AC to DC efficiency:
350W Load Waste Heat
Waste heat DC-DC:
Waste heat AC-DC:
Waste heat overall:
Conclusion
So the difference in waste heat for the DC-DC units is noticeable from these calculations, with the 12V DC-DC being able to get away with a smaller heatsink in comparison. I was a bit conservative with the 24V efficiency number though, so the actual difference may be less pronounced.
Another difference is the amperage between the AC-DC adapter and the DC-DC board. Standard Molex Mini-Fit Jr terminals are only rated for 9.0A and that's best case, the current capacity derates with wires small than 18AWG, increased circuit count, and temps higher than 30°C delta over ambient.
Which explains the 8-pin connector on the high-wattage Dell 12V bricks and the 6-pin input on the 300W HDPLX DC-DC.
Efficiency Specs
DC-DC efficiency assumptions:
- 12V input DC-DC: overall 98% efficient
- 24V input DC-DC: overall 94% efficient
AC-DC efficiency figures w/ 115V AC input:
- 12V ouput AC-DC: EPP-400-12 @ 90% load = 89.5%
- 24V ouput AC-DC: EPP-400-24 @ 90% load = 90.5%
======================================================
350W Load Calculations
DC-DC efficiency calculations:
- 12V input DC-DC: 350W / 0.98 = 357W
- 24V input DC-DC: 350W / 0.94 = 372W
AC-DC efficiency calculations from above:
- 12V output AC-DC: 357W / 0.895 = 399W AC
- 24V output AC-DC: 372W / 0.905 = 411W AC
AC-DC to DC-DC amperage:
- 12V: 357W / 12V = 29.8A
- 24V: 372W / 24V = 15.5A
- 19V: 372W / 19V = 19.6A (assuming 94% efficiency)
======================================================
350W Load Efficiency
AC draw at the wall:
- 12V: 399W
- 24V: 411W
Overall AC to DC efficiency:
- 12V: 87.7% efficient
- 24V: 85.2% efficient
350W Load Waste Heat
Waste heat DC-DC:
- 12V: 7W
- 24V: 22W
Waste heat AC-DC:
- 12V: 42W
- 24V: 39W
Waste heat overall:
- 12V: 49W
- 24V: 61W
Conclusion
So the difference in waste heat for the DC-DC units is noticeable from these calculations, with the 12V DC-DC being able to get away with a smaller heatsink in comparison. I was a bit conservative with the 24V efficiency number though, so the actual difference may be less pronounced.
Another difference is the amperage between the AC-DC adapter and the DC-DC board. Standard Molex Mini-Fit Jr terminals are only rated for 9.0A and that's best case, the current capacity derates with wires small than 18AWG, increased circuit count, and temps higher than 30°C delta over ambient.
Which explains the 8-pin connector on the high-wattage Dell 12V bricks and the 6-pin input on the 300W HDPLX DC-DC.
Looks pretty good. Keep in mind we're talking about a load switch PDCB design. It is possible to bypass a large chunk of current by supplying power straight from the PSU to the component. I have just tested it and didn't notice anything adverse. I supplied 12V from my Meanwell straight to by GPU; boots on just fine, didn't fry anything.
The 9.0A rating is for the terminal, if we go for the up-rated Mini Fit PLUS we can have 13A on a single terminal. Also, I don't see why we would use anything smaller than 18AWG for mini-fit. 20AWG is noticeably smaller.
Ah, that's true, that would slightly increase the overall efficiency.
Hmm, for some reason I was thinking the high-current terminals were only available in female for wire-to-board applications, but I stand corrected.
And for the short cable lengths we're dealing with, there's not much advantage I see to 16AWG either. So 18AWG seems to be the sweet spot in wire gauge.
Do you mean that the G-Unique brick is a 12V 220 DELL unit ?
In that case I can't use it for my thin-itx build, which motherboards only takes 19V for input on the 7.4mm barrel / outputs 19V on the internal 2Pin inlet...
@guryhwa mods both the 12V 220W and 19V 330W Dell bricks. I believe the modified 19V puts out up to 500W at 18V. However, he changes up the plug to handle the additional amperage, although I believe one of the ways he can do this is with dual barrel plugs.
That means there are both 12V and 19V G-Unique DC boards, depending on the power ?
I need one to power a Thin Mini-ITX system.
The idea is to hook up my own 19V brick to the onboard 7.4mm barrel, then power the G-Unique board through the onboard 2Pin inlet that can act as passthrough output.
But this inlet only outputs 19V.
I need one to power a Thin Mini-ITX system.
The idea is to hook up my own 19V brick to the onboard 7.4mm barrel, then power the G-Unique board through the onboard 2Pin inlet that can act as passthrough output.
But this inlet only outputs 19V.
That means there are both 12V and 19V G-Unique DC boards, depending on the power ?
I need one to power a Thin Mini-ITX system.
The idea is to hook up my own 19V brick to the onboard 7.4mm barrel, then power the G-Unique board through the onboard 2Pin inlet that can act as passthrough output.
But this inlet only outputs 19V.
What do you need the G-unique to power? The the barrel plug for the thin itx powers the whole board and the pcie as well. I believe the pcie is only rated for 35W.
If you are just powering the motherboard you just need a regular 19V brick with the corresponding barrel.
I need to power a GTX 1060 as well 
Here is the first version, based on and HDPLEX board :
The green PCB is an Add2PSU that will synch the DC board with the motherboard.
I was hoping to getting rid of the 24P cable by using a direct-plug DC board.
Here is the first version, based on and HDPLEX board :
The green PCB is an Add2PSU that will synch the DC board with the motherboard.
I was hoping to getting rid of the 24P cable by using a direct-plug DC board.
I need to power a GTX 1060 as well
Here is the first version, based on and HDPLEX board :
The green PCB is an Add2PSU that will synch the DC board with the motherboard.
I was hoping to getting rid of the 24P cable by using a direct-plug DC board.
What you need to do is request a custom smaller wide-input (19V) to 12V 6pin PCIE board from G-unique. This is not the product that you want.
However, I'm not a fan of the barrel connector, because at 150-180W usage you are close to its max specs.
If you want to keep it simple use a dedicated 19V board for your 6 pin pcie. Request a modded Dell brick that has two external plugs so one can go straight into the 19V to 12V pcie board.
Edit: You can also run dual bricks. One 19V, one 12V. Some high power systems actually uses two bricks instead. The 1060 will need about 120W for its own usage.
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Thanks a lot for your input.
In the case of a custom PCB / single 12V brick dedicated to the GPU, how do you synch this power source with the motherboard when you power on the system ?
PS : One member of the forum is working on such a board but I'll him disclose his project to you
EDIT : Something like this ?
https://bitcointalk.org/index.php?topic=1627191
In the case of a custom PCB / single 12V brick dedicated to the GPU, how do you synch this power source with the motherboard when you power on the system ?
PS : One member of the forum is working on such a board but I'll him disclose his project to you
EDIT : Something like this ?
https://bitcointalk.org/index.php?topic=1627191
Thanks a lot for your input.
In the case of a custom PCB / single 12V brick dedicated to the GPU, how do you synch this power source with the motherboard when you power on the system ?
PS : One member of the forum is working on such a board but I'll him disclose his project to you
EDIT : Something like this ?
https://bitcointalk.org/index.php?topic=1627191
You don't need to sync it. The GPU regulators have an on and off state. When turned on they regulate. The GPU on and off state is controlled by the motherboard. The 12V will be sitting at your GPU connector ready to be used. When you turn on your computer, the GPU will then start pulling current.
What it does mean is that your computer is always energized even when it is off, which is true for most brick based builds. So don't touch anything if your computer is plugged in, even when off.
Regular ATX PSU uses a logic called ps_on, which is activated by your motherboard. It is a latching low signal, once activated then your PSU turns on and pushes 12V to the computer. This saves energy and is safer. Most bricks don't have this feature and are in an always on state.
The link you shared is not what you want. If you are using a single 19V brick then you need a step down DC regulator to 12V. If you are using dual bricks including a 12V, you just wire it straight to the GPU.
@Thehack I believe people who have done this before have cut the power traces to the PCI-E slot because they are worried that the card will pull over 35W. Mentioned here: H2O-Micro (sub 3 Liter Custom Watercooled Gaming Rig) (he uses a custom PCB vs actually cutting the traces, but effectively the same thing.
Might be a better idea to use a 1050ti with a 6 pin plug instead. Or possibly a 470 detuned to use 100W.
There are also risers that have inputs for 12V. I assume that is what the build will need a riser.
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