An Interesting DC 12V Power Supply

[bkydcmpr]

30mm thick and inexpensive.

http://www.trcelectronics.com/View/Mean-Well/LRS-350-12.shtml

I'm thinking to use it in an eGPU box, install this power supply and the video card back to back, the total width probably could be under 80mm. However, this is not a PC power supply, I don't know if there would be any issue.

 

[Thehack]

It is fairly long so you'd have to find a place to fit a AC in plug.

It spec sheet exceeds the peak ripple allowed for ATX power specs. However actual measured use may be okay.

 

[Sicaris]

As a side note on ripple, are motherboards and GPUs designed to stop pulling power if the ripple is too large or will they fry?

 

[Thehack]

As a side note on ripple, are motherboards and GPUs designed to stop pulling power if the ripple is too large or will they fry?

I'm not aware of any motherboard who would stop power based on sensors that detect ripple.

 

[bkydcmpr]

It is fairly long so you'd have to find a place to fit a AC in plug.

It spec sheet exceeds the peak ripple allowed for ATX power specs. However actual measured use may be okay.

I see. ATX requires 120mV max peak to peak, this one is 150mV, 25% out of the spec. But if measured against the overall voltage, the difference seems to be tolerable (1.25% vs 1%).

The length won't be an issue in my case, I would use Zotac 1080 Mini, 211mm in length, a perfect match of this power supply (215mm) if counts the bracket in.

 

[confusis]

Would throwing a capacitor across the output help smooth the ripple, or is it too 'fast' for a cap to help with?

 

[Thehack]

Would throwing a capacitor across the output help smooth the ripple, or is it too 'fast' for a cap to help with?

If that's the serious question, then yeah, you'd use caps to smooth it. It needs to properly integrated by an electrical engineer. These things are designed for certain applications so they didn't need something as tight as 120mV pk-pk. That's about 1% voltage variance so pretty damn small when you think about it. The spec sheet for that PSU says they measured 123mV Pk-Pk. You can probably get away with it, but your VRM/Caps probably won't like it long term. The effects are hard to know unless an EE can chime in.

 

[confusis]

It was a serious question, as it would open up this unit for use in designs

 

[bkydcmpr]

Found some detail pictures on eBay https://www.ebay.com/p/?iid=141567734411

Seems I can directly drill mounting holes in the back for pci-e board standoff screws to save more space.

 

[bkydcmpr]

IEC 320 C6 seems to be a better choice for AC receptacle than common IEC 320 C14 in compact design.

 

[EdZ]

C5/C6 (and C7/C8) have a max current limit of 2.5A. For 230V systems this is 575W, but for 110V systems it's only 275W. And that's the input load, not the output power, so available DC power will be reduced depending on PSU efficiency (e.g. an 80Plus Gold PSU on 110V will only give you a peak system power of 240W).

 

[bkydcmpr]

C5/C6 (and C7/C8) have a max current limit of 2.5A. For 230V systems this is 575W, but for 110V systems it's only 275W. And that's the input load, not the output power, so available DC power will be reduced depending on PSU efficiency (e.g. an 80Plus Gold PSU on 110V will only give you a peak system power of 240W).

These C6 parts at newegg have different ampere rating under 230V and 120V:
https://www.newegg.com/Product/Product.aspx?Item=9SIA4SR1T50773
So 7A under 125V gives you 875W, that's plenty for a compact system.

 

[jeshikat]

Considering the website for that seller doesn't even own their domain name, I'd treat their ratings with a grain of salt.

The IEC 60320 specs only rates C5/C6 for 2.5A, so I'd only use higher-rated parts from reputable companies.

 

[bkydcmpr]

Considering the website for that seller doesn't even own their domain name, I'd treat their ratings with a grain of salt.

The IEC 60320 specs only rates C5/C6 for 2.5A, so I'd only use higher-rated parts from reputable companies.

The current rating is based on 250V AC apparently, under 125V C6 is actually rated at 10A, so yeah, the part rated at 125V/7A can be considered as low quality, the seller seems to be honest enough though. I'll keep looking for a compact full 10A C6 plug.

Here is a link to a IEC 60320 reference page:
http://www.stayonline.com/reference-iec320.aspx

EDIT: Although the specs say C6 is rated at 125V/10A, the products I've seen so far are either rated at 125V/7A, or doesn't provide the rating under 125V, but I'm pretty sure it's enough for any eGPU or mini-ITX system. I guess the Swiss brand Schurter 2563 is the top notch, $1.62/pc but the minimal order is 100pc.

 

[bkydcmpr]

I placed the order for the power supply, I'll play with it. According to Aibohphobia's video, the width of video card + PCIe board is about 56mm, so the overall front size of the enclosure would be around 95mm x 150mm, which is ugly I have to admit, but there is one advantage, I can install a standard 92mm front fan like Noctua NF-A9x14. Ideally I would rather have it 12 mm narrower and use a 80mm fan instead. An engineer from Fairchild was able to build a 300W 12V power supply as thin as 18mm in 2010 (https://www.slideshare.net/SteveMap...low-profile-acdc-powersmappus-may-2010edit-sm). I already found some products at 20mm (but over 300mm in length), my idea is, looking beyond the PC parts.

UPDATE: Here is one (http://www.mouser.com/ds/2/281/mvac400-463546.pdf), 400W with active PFC, 1% ripple, 30x76.2x127. Install it back to back to the video card the width is about 70mm, side by side with the Thunderbolt board the total length is around 240mm, the height is totally fit, give some room on each side the total size is still manageable. A little pricey at $170.

EDIT: I was a little over-optimistic about Murata MVAC400, it's open-frame so the PS needs standoffs too, that will bring the overall width of PS+video card to 77.95mm, so it's the right dimension to fit in a 80mm front fan. Including the bracket, Zotac 1080 Mini is about 227mm in length, so 240mm of the PS+Thunderbolt board is close to a perfect match. There are 18mm space behind the Thunderbolt board will be wasted, maybe I could squeeze a Schuter 2563 C6 plug over there (19mm if rotate 90 deg). I guess it's hard to find anything better than this combination, I'll start the actual layout when I have time.

EDIT 2: I could think straight. This $170 power supply measured at 37.96x76x127, and it's open-frame and passive cooling, isn't it the same if mini-ITX PS removed the chassis and cooling? Now I'm back to the origin.