- Oct 20, 2016
Just a question of curiosity to better understand why it wouldn't work or wasn't done.
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?
So I did some rough calculations regarding efficiency and heat dissipation.
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:
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
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.
It is possible to bypass a large chunk of current by supplying power straight from the PSU to the component.
Also, I don't see why we would use anything smaller than 18AWG for mini-fit.
I believe they said this unit took a 12V input.
Aside from that, it's more efficient to get a 12V input since that's the most used voltage rather than creating heat converting a voltage you can't use to one you can.
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 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.
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 ?
@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.