EEV blog: digitally programmable modules

[6PTsocket]

I just watched Dave review these digitally controllable modules that use a "power pack" as an input. Is that a "wall wort" in American? For higher power they go to a two piece setup with a control panel and a separate buck converter. There are other videos out there, too. Every one is using a lab power supply, that far out performs  rhe item in question, as a source of "raw" DC. Clearly, if I owned a lab supply of that quality I would not be looking at these modules. I understand it is just for demo. I am not familiar with " power packs" that can supply 30-40 volts at 5-10 amps. How clean do they have to be? Are they switching, or just a transformer, bridge and filter cap? Can somebody please steer me to what is supposed to be the input for these devices, obviously it is not a lab supply. They seem to out perform a cheap switched  bench supplies. They all seem to have model numbers DSPxxxx. You can even get kits with a case and binding posts so only the power pack is outboard. Are they a better way to go than a cheap switched supply. While clumsier to program they seem to perform better. Thanks.

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[rstofer]

You need to feed these modules with raw DC power at some voltage level which is a function of the actual module.

Here's one description:

https://www.banggood.com/DP50V5A-Buck-Adjustable-DC-Power-Supply-Module-With-Integrated-Voltmeter-Ammeter-Color-Display-p-1050061.html?rmmds=buy&cur_warehouse=CN

Notice that it is a BUCK converter...

According to the description, the input voltage needs to be 1V higher than the maximum output so, for a 50V output, you need to provide 51V input.  It definitely needs to be DC and I don't think it needs to be particularly noise free.  I would try a bridge rectifier and some large smoothing capacitor.  I don't know how big!  Maybe 100 ufd, maybe 1000 ufd, I would grab something laying around and try it while looking at the output with a scope.

[6PTsocket]

You need to feed these modules with raw DC power at some voltage level which is a function of the actual module.

Here's one description:

https://www.banggood.com/DP50V5A-Buck-Adjustable-DC-Power-Supply-Module-With-Integrated-Voltmeter-Ammeter-Color-Display-p-1050061.html?rmmds=buy&cur_warehouse=CN

Notice that it is a BUCK converter...

According to the description, the input voltage needs to be 1V higher than the maximum output so, for a 50V output, you need to provide 51V input.  It definitely needs to be DC and I don't think it needs to be particularly noise free.  I would try a bridge rectifier and some large smoothing capacitor.  I don't know how big!  Maybe 100 ufd, maybe 1000 ufd, I would grab something laying around and try it while looking at the output with a scope.

I am well aware of the requirements as far as input voltage and that there is a drop through the buck converter. I just don't recall seeing high power 'power packs' Wall worts are usually 1A or less. How about a link to to some raw DC supply that is good for 5-10 A. Without something beyond theoretical to feed these suckers, they are only useful if you have some fixed supply on hand. The video just said to use a  power pack, whatever that means. No place do I see any info on how much pre filtering or pre regulation is required for a good output. All the info with these items is in bad English.

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[viperidae]

I use a 48v 3a PSU for one of those. It's a 50v 15a version. They're pretty common, usually used for poe injectors.
They look like a big laptop power brick.

[mikerj]

I just don't recall seeing high power 'power packs' Wall worts are usually 1A or less.

It's "wall wart" i.e. a lump sticking out of the wall.  Wort is a liquid you get when brewing beer 

Quite often people use laptop chargers with these modules, which are good for 20v and 4amps for the larger ones.

[tooki]

Or you use an industrial power supply (like something from MeanWell) that's intended for being put inside a housing.

[AngraMelo]

I have several of those and they are great. Mind you that they are not as efficient as advertised and that they do carry some high frequency noise.
I just use some switch mode PS`s that are normally used to power LED strips.

Like this:
https://www.banggood.com/AC-220V-To-DC-12V-10A-120W-Power-Supply-Lighting-Transformer-Adapter-Driver-For-Strip-Light-Lamp-p-1145387.html?rmmds=search&cur_warehouse=CN

Ruideng is the manufacturer himself. They make some buck/boost as well. It is worth noticing that they all have a sweet-spot as for input voltage and current. For example their buck/boost module that can go up to 32V and 5A is most efficient when powered with a 24V 10A supply.

Also take in consideration that their advertised maximum input current is always a bit generous. At their limit they are glowing red hot and I dont think you should count on their quality to keep them at maximum output power.

Be on the safe side, by something that has a larger power output than you might need!

[6PTsocket]

Thanks all. I started reading over the hundereds of comments to the blog and my question was asked by others and got similar replies. That LED supply is the least expensive solution with a lot of watts/$. I was thinking of going overkill just, as you say, not to push the devices not too hard. Funny, I actually hesitated for a second when posting; is it wort or wart? I chose wrong. LOL

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[amlu]

some of them are buck (stepping down) some buck-boost (up and down)

you can power it up from something like meanwell 24/36 10a supply
im using a couple on my test bench, all works as expected i never had a need for a proper bench power supply.

this is afaik the official store of original china seller:
https://www.aliexpress.com/store/product/RD-DPS5015-Constant-Voltage-current-Step-down-Programmable-digital-Power-Supply-buck-Voltage-converter-color-LCD/923042_32702714880.html?spm=2114.12010615.8148356.6.18d46f8fH8jOdu

[Vincenzo]

This is my first post and I tried to avoid starting a new topic about an item that was discussed in this relatively old one.

I had one of those (5A 50V) and it worked fine for over a year and is still good. I just never could (or could find clear instructions about) saving the 2 or three presets (M0, M1, & M2) that the makers advertise.

It is not a critical thing and does not affect the bang/buck value much, but I noticed that the Chinese guys who make them corresponded with Dave on one of the videos which gives me hope that it is closer to a legit product and that there IS away to use that feature. I tried all kinds of ways and button combinations that make sense or that other power supplies do or if there is a way to reprogram/update/reset it in vain, and it is the closest thing to black magic or scam. Curiosity is killing me and whenever I look at the thing, I grab it and start pushing buttons trying to make the discovery.

Does any one know how to use those memories?

[Vincenzo]

This is my first post and I tried to avoid starting a new topic about an item that was discussed in this relatively old one.

I had one of those (5A 50V) and it worked fine for over a year and is still good. I just never could (or could find clear instructions about) saving the 2 or three presets (M0, M1, & M2) that the makers advertise.

It is not a critical thing and does not affect the bang/buck value much, but I noticed that the Chinese guys who make them corresponded with Dave on one of the videos which gives me hope that it is closer to a legit product and that there IS away to use that feature. I tried all kinds of ways and button combinations that make sense or that other power supplies do or if there is a way to reprogram/update/reset it in vain, and it is the closest thing to black magic or scam. Curiosity is killing me and whenever I look at the thing, I grab it and start pushing buttons trying to make the discovery.

Another super weird thing that no sane designer would do. in the main screes (1 attached) simple clicks to the top and bottom buttons or even rotating/pushing the encoder do nothing at all. What planet did they come from !?

Does any one know how to use those memories?


Attempts:
1. tried going to one of the memories by long pressing one of the three buttons from screen 1 (below), then going to screen 2 and changing the voltage and current. when going back to screen 1 and long pressing any button (to switch to a different saved! setting) it is always 5v and 5.1a.
2. Then I tried doing the same thing as "1" but with the last line of screen 2 that says "M-PRE" set to all three M's and with the value next as OFF or ON, and nothing works as would be expected 

[mikerj]

This video may help:

[Vincenzo]

IT WORKED!!!!!

Thank you mikerj for the video that I couldn't find when I searched. All videos/forum-posts I found totally ignored the memory thing. It is like the deepest CCP secret.

After spending a relatively long time deciphering the accent and the convoluted philosophy behind the interface, I started crying tears of joy because we ("Yanks" as Dave calls us in his vids) seriously do not appreciate what we have, summarized by words like "INTUITIVE" & "COMMON-SENSE".

I wonder if they ever get feedback that shows them how crazy this is? Using it is a puzzle and there should be a trophy to the customer who solves it.
Criticism aside, it's still great bang for the buck!

*pardon the font in the image attached, it's from an overpriced MyCAD software