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Grogster
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Posted: 12 November 2016 at 3:05am | IP Logged Quote Grogster

I have been playing with these little modules today:





You can find them all over eBay by searching for MP2307.

I'm not impressed, and my own personal tests on these have resulted in me rejecting them as they seem to be either a bad design around the regulator chip, or just a bad regulator chip design in general.

Datasheet says standby current should be 1.5mA max, but the no-load current of all the modules I tested(I have 10) are all about 75mA in standby with no load, and they get remarkably hot at that 75mA with no load, so I would be concerned about putting any REAL load on them.

They are rated for 2A continuous, and 3A surge, but with 300mA on them, they are hot enough to roast a chicken. Not good. About 80'C so says the laser temp probe.

They are cheap and nasty eBay ones, and perhaps I got a bad batch?
In any event, back to more reliable factory-traceable regulator parts for now.....

I had not used these in anything, am only bench-testing and load testing them, but I am not happy with the results so I won't be using them in anything either!

If anyone else has used these modules, I would be very interested to hear if they have had the same problems - or not.

EDIT: Under about 500mA load, the temp goes up to about 95'C(holy cow!), and the output voltage dips from the set 7v down to about 6.2v which for a 3A rated regulator is pretty poor if it can't maintain it's output voltage under load - a load well within it's specs if the datasheet is to be believed.

Edited by Grogster on 12 November 2016 at 3:07am


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WhiteWizzard
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Posted: 12 November 2016 at 6:37am | IP Logged Quote WhiteWizzard

All I can say is (and enjoy your roast chickens!)

Please let us know how hot they get at 3A, assuming you survive the thermal shock-wave . . . . .

Edited by WhiteWizzard on 12 November 2016 at 6:38am


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bigmik
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Posted: 12 November 2016 at 6:51am | IP Logged Quote bigmik

Hey!

I bought some that arrived a couple of weeks ago, these had the diode RedRok (I think) mentioned... I need to try to locate them under the pile of crap in my `cave'.

I was seriously impressed by their size (or lack of it) but the tests you have done do not sound promising.

What voltage IN and OUT are you `using' these on?

Kind Regards,

Mick

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Grogster
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Posted: 12 November 2016 at 7:45am | IP Logged Quote Grogster

@ WW - Yeah, at that price, I was not really expecting much, and the bench-test proved as much.....

@ Mick - Input voltage 12v, output voltage 7v. PDF for the MP2307 says they can have an input voltage of 4.75v to 23v, adjustable output between 0.9v and 20v, so well within the spec.

Those ones in the picture at the top of the thread are TINY being only about 10mm x 15mm or so. It's back to the LM2596 modules - they do seem to do what is advertised, but are about twice the size.

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Posted: 12 November 2016 at 8:20am | IP Logged Quote matherp

Quote:
adjustable output between 0.9v and 20v, so well within the spec.


If you look at a good datasheet for this sort of regulator you will see that the inductor has to be selected based on both the input voltage and the output current. It is impossible to design a circuit that will work efficiently over the ranges advertised.

Look at page 19 of the LM2596 datasheet and you will see this applies as much to this device as any other regulator. The difference with the LM2596 modules is that at least they chose a reasonable inductor for "average" use
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greybeard
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Posted: 12 November 2016 at 9:24am | IP Logged Quote greybeard

The guys on this site have done a quick review/test on them as well
DCDC-MINI360 Note the commnet regarding input capacitance.
I was looking at them for a simple (cheap) regulator for connecting a small (10W) solar panel to a battery to limit any over voltage. After releasing the smoke on one of them I realised that they have a synchronous output stage and when I connected them to a battery the o/p tried to shunt the battery to earth with a resultant release of the smoke.
I have added a series diode in the output to prevent this from happening but it doesn't add to the efficiency of the system.
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Grogster
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Posted: 12 November 2016 at 10:42am | IP Logged Quote Grogster

@ matherp - Gotcha, thanks for that info.

@ greybeard - Thanks for the info and link. I will read that.

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