Multiple or Single Power Supply for Consumer Electronics - Page 1
Forum section: electronics / beginners

author: JaredKat
author_rank: Newbie
timestamp: November 05, 2016, 11:05:58 pm
content: Hello all, first post, long time enthusiast and subscriber to the Youtube of EEVblog.To the question:For consumer electronics, I'm trying to be a bit power-aware and whatnot, and am wondering if it'd pull less pixies from the wall if I went with a single, higher-amperage power supply rather than multiple lower-powered supplies.As I'm aware, each power supply has it's own voltage regulation, transformers, and other components creating voltage drops and pulling wattage away from the efficiency of the supply.So I was curious if it'd be of any benefit to grab a higher-amp power supply at the same 12v and pull multiple leads from the output to other 12 volt components. If anything it could help with cable management. Sure, this definitely wouldn't be measurable if devices are only on for a short period daily, but these are on 24/7 so I do want to take some care on keeping wattage down.Let me know, I'm a bit curious.

author: tautech
author_rank: Super Contributor
timestamp: November 06, 2016, 12:24:38 am
content: Welcome to the forum.Fact is, most consumer electronics have SMPS PSU's these days and design of such with multiple voltage outputs is very straightforward. Multiple windings, rectification and smoothing for each rail is common but usually only 1 rail is regulated by the SMPS controller IC. When more rails need be closely regulated then additional regulators are added after the PSU, sometimes locally, sometimes remotely.

author: thunderbolt87
author_rank: Contributor
timestamp: November 06, 2016, 01:34:05 am
content: Hi,@tautechI think JaredKat asking if it's sensible to replace several plugpacks with a single beefier one.@JaredKatAll those plugpacks for each and every bit of consumer gear seem wastefulbut let me please explain why I don't see a viable alternative.Ideally, we'd have low-voltage DC from dedicated DC wall warts.That'd be one beefy SMPS from 110/220V to 48V (like PoE) or to 12V (as you desire).As tautech pointed out, there might be need for per-load regulation after the beefy converter.Let's assume it's NOT needed for the sake of simplicity.So the question is... Will this single beefy converter be more efficient?Plugpacks, in theory, are not that bad. Manufacturers should pick the right one in terms of current draw.Their operating points, ideally, should be "no load" or "optimal load" on average.Losses should be quite low there.I think, in one of Dave's videos, he showed us the efficiency curve of a DC/DC converter (from the data sheet).The SMPS' should look quite similar.Now, if you know the total average current draw of all your 12V devices you can go build a SMPS of your own. It might also be more efficient than those plugpacks in total.However, when you change the load on your converter, you might be less efficient.To sum up...you can build a converter which is matched to one load (plugpack)you can't build a universal converter that's say 95% efficient with every load (single beefy converter)So several load-optimized plugpacks can well outperform a beefier non-optimal converter.Will you build a new converter every time you change the load (buying more consumer electronics)Also, per-load regulation would further reduce overall efficiency.Hope you're not too disappointed with my response.I can't give you any real numbers here, just thoughts.