DPS5020 dual power supply build

[kitedude]

Hey guys sorry to be off topic but there's no point in opening a new thread. I have the dps5020 and I've blown the mosfets which I've replaced but the D5 diode is unrecognizable. Anyone knows what it is and where does the cathode go? (left or right) I'm a noob so I know nothing about anything. Complicated answers will not be understood.
Damage was due to reverse polarity for a second but it worked for months with bulged mosfets, then the final blow was more input voltage than 50v.

[megaraider]

Re: DPS5020 dual power supply build

I wonder if THIS technique Dave talks about can be used here as well...

Short answer: Yes
Long answer:
But has said before you´ll have to draw a line where you want to stop the increase in complexity and cost vs. the ripple output noise.

IMO in a typical "all terrain" workbench power supply, meant to drive high power loads, tens of mV ripple output noise are well neglected.

But again it all comes down to type of use you'll expect to give it...!
If, on other hand, you will mainly use it to drive low power, sensitive, circuits, lets say for example 1.8V audio or frequency related circuits, then tens of mV ripple on the voltage rail will be unacceptable.

[Dannyx]

Re: DPS5020 dual power supply build

I wonder if THIS technique Dave talks about can be used here as well...

[megaraider]

Re: DPS5020 dual power supply build

Seen the videos and ripple measurements.

IMO, taken in consideration the specs (and price!) the ripple results fall within the advertised 100mV typical, reaching 150mV @ maximum current output (6A), which should be considered the worst case scenario.

Ultimately it will come down to what you will be using it.
Although, as a general rule, variable linear power supplies have less ripple than switched power supplies, this however heavily depends on the load.
Furthermore, variable linear power supplies are prone to overshot and undershot the output voltage.

As an example, ripple and overshot / undershot wise:
if the load being powered changes and fluctuate heavily and fast over time then a variable linear power supply will, most likely, perform worst than a switched power supply.

[Dannyx]

Re: DPS5020 dual power supply build

The transformer shown in the schematic for that linear supply on Ali poses a problem, since I don't have that many taps to play with. I only got one center-tapped output, so I don't think it'd work with just that. I'd be able to create the split-supply at the top (L2), but I would have nothing to power the "hot" side at the bottom.....

[Dannyx]

Re: DPS5020 dual power supply build

Yes, I watched that one too, but wonder if it applies to the ones I have...I don't have a scope myself, so I don't know how bad the noise on these can get and whether I should even be concerned in the first place....

[stj]

Re: DPS5020 dual power supply build

make sure if your watching jones's initial review, that you watch his followup/oppology.
he miss-read the noise in the first video by a huge factor!

[Dannyx]

Re: DPS5020 dual power supply build

Back on this supply project, since it's been lying dormant for quite some time now, my original plan was to have two DPS modules side by side, but that got me thinking whether it'd be a good idea for the second module to be a linear supply which would supposedly give me a less noisy output. I got the idea after watching a video of Dave Jones where he shows the noise output of those switching DC-DC supplies I'm using here....it's probably of no concern to me, since I don't work with things that require that sort of precision, but I'm still considering it.

I found this thing on Ali, but I wonder if it can do constant current mode or it's just one of those "trip-point" current settings like I had at my old shop. It did the job, but it'd still be nice to have something that automatically brings down the voltage to maintain constant current. That one just beeped and cut the output entirely...

[megaraider]

Re: DPS5020 dual power supply build

so after all the talk about safety you build it in a flamable housing made from dead tree carcase!

That was the option at the time. It's probably not THAT flammable....or at least it hasn't been so far

At least it's an isolated housing... well exception made to the screws that go through it
(Just joking, don't take my comment to serious)

[Dannyx]

Re: DPS5020 dual power supply build

That was the option at the time. It's probably not THAT flammable....or at least it hasn't been so far

[stj]

Re: DPS5020 dual power supply build

so after all the talk about safety you build it in a flamable housing made from dead tree carcase!

[Dannyx]

Re: DPS5020 dual power supply build

Just thought I'd share with you guys some pics of my first DPS supply build.

The case work belongs entirely to my old man, so I take no credit for that

The IEC 13 inlet I used on the back has 2 Y caps going between each of the "live" wires and PE (which is useless ATM, because there's no earth on most outlets around here). The PCB on the back where the choke is, is an EMI filter I pulled out of an ATX supply or something, already assembled like that: mains comes in, mains comes out. I thought I'd install it just for the sake of it, though I have no idea if it actually helps in any way or not. It's got some Y caps of its own there, plus some resistors, an X cap and that choke. I actually took some close-ups of this board and discussed it someplace else, but can't remember where right now, unless I start searching around my older threads...

What it's lacking is X caps across the two-pole main power switch on the front panel (right of picture) and Y caps+resistors between secondary GND and PE like we've discussed and debated over...

[megaraider]

Re: DPS5020 dual power supply build

No reverse polarity protection ? I think I'll be adding a diode myself, having heard about these having a tendency to blow up like this

[Dannyx]

Re: DPS5020 dual power supply build

No reverse polarity protection ? I think I'll be adding a diode myself, having heard about these having a tendency to blow up like this

[stj]

Re: DPS5020 dual power supply build

people have done that mistake before, there is a thread on eevblog about it with the guy who designed it posting some info

[Dannyx]

Re: DPS5020 dual power supply build

I could provide some close-up pics of my board if you think it'll help you, but can't possibly know any of the values unfortunately...maybe try chatting with a seller on Aliexpress see if they got a schematic they're willing to share :|

[emir0815]

Re: DPS5020 dual power supply build

Hi guys,

I connected a battery with reverse polarity and some parts blew up. Does someone have details on
1. F1 rating
2. component left of F1
3. component above with DT on the pcb

I do have a dps5020

Thanks in advange
Karl

[stj]

Re: DPS5020 dual power supply build

yes, there is a plug and socket or a atleast a junction-box for fixed / industrial stuff.
the supply side is "infrastructure" the thing connected is an "appliance"

different rules apply to each.

[eccerr0r]

Re: DPS5020 dual power supply build

So is there a difference between end equipment and building code rules and hence is why post 105 is confusing?

[stj]

Re: DPS5020 dual power supply build

end equipment often has double-pole switching - it just makes sense once you understand that earth-neutral bonding cant be assumed.

what if it's an old building with earth on a gas-pipe or just non-existant?