miniature DC-DC converter suggestions....SOLVED...sorta

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All,

 

I have a design using a Torex semiconductor DC/DC converter IC: https://www.torexsemi.com/file/x...

 

That just will not work properly.  In fact I have the same circuit in another board design that DOES work using the same exact components, the only difference being the component layout due to size constraints.  The circuit that works has the parts located closer to the IC than the non working one, which the datasheet does say that the components need to be as close as possible.  The difference in distances between both boards is not that much, but it is what it is.

 

The symptom on the non-working unit is that any small surge causes the device to shut down, and it will not supply more than 150 milliamperes without shutting down.  I get the full 1 amp output on the working design.

 

I have been fighting with this for over a week now and I need to come up with a backup plan.  I was wondering if anyone could recommend a miniature dc-dc module that could take in 12vdc and output 5vdc at almost an amp of current...and be as low profile as possible...5mm max?

 

THanks

Jim

This topic has a solution.

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Last Edited: Mon. Feb 5, 2018 - 03:23 PM
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Does Recom have anything suitable?

 

Ross McKenzie ValuSoft Melbourne Australia

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Some time ago I bought a bunch of MP1584 boards from Ali. Quite nice.

I did some tests, overloading and short circuiting it, but it survived them all.

And with a programmalabe switching frequency between 100kHz and 1.5MHz it needs a small inductor.

https://www.aliexpress.com/whole...

 

PCB layout and signal routing (& component choice) is critical in SMPS design.

An absolutely marvelous pdf is an25fa "Switching Regulators for Poets", "A Gentle Guide for the Trepidatious" by Jim Williams 1987.

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Last Edited: Fri. Feb 2, 2018 - 04:45 PM
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Lots to choose from here:  http://www.prodctodc.com/

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@paulvdh

Those are some great links!  I will order some of those supplies if they fit the board...gotta get the calipers out and measure.  Might take the plunge and order 25 of them to keep around, but $25.00 for 50pcs is hard to pass up as that would give me another trinket to put in my care packages I send you to freaks wink

 

@jim,

Some good stuff on that site you posted as well.  Going to do some window shopping

 

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

This reply has been marked as the solution. 
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jgmdesign wrote:
All,   I have a design using a Torex semiconductor DC/DC converter IC: https://www.torexsemi.com/file/x...   That just will not work properly.  In fact I have the same circuit in another board design that DOES work using the same exact components, the only difference being the component layout due to size constraints.  The circuit that works has the parts located closer to the IC than the non working one, which the datasheet does say that the components need to be as close as possible.  The difference in distances between both boards is not that much, but it is what it is.   The symptom on the non-working unit is that any small surge causes the device to shut down, and it will not supply more than 150 milliamperes without shutting down.  I get the full 1 amp output on the working design.   I have been fighting with this for over a week now and I need to come up with a backup plan.  I was wondering if anyone could recommend a miniature dc-dc module that could take in 12vdc and output 5vdc at almost an amp of current...and be as low profile as possible...5mm max?   THanks Jim

 

Just an update on the O.P....Original Problem.

 

It seems to be resolved, and I am not sure if I am puzzled, or annoyed.

 

The fix was to lift the SYNC pin from ground as I had it, and put a 1000pf cap from the pin to ground in the non-functioning unit.  If oyu look at the designs in the datasheet they all have the pin set up this way, but in this one spot on page 12 of the datasheet it says:

 

The SYNC pin is soldered right to the ground plane on both boards.  Why on one this is a problem but not on the other?  I checked the markings and they are the same.  Vendor sent me the delivery bags that the parts came in from and they are from the order I placed with Mouser.  WTF.

 

Well isolating the pin from ground and tacking the cap from the pin to ground fixed the problem, but I am pretty pissed as these boards cost over $150.00 each to have made with parts.  Now I have a cut and kluge on them.

 

At least this looks better than removing all the parts and placing the modules I was going to buy....and still might too for that matter.

 

Cheers,

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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I have been using the following DC-DC buck converters for a while and they seem to be quit stable and are able to put out 1.7A continuously.  They are quite small.

 

https://www.aliexpress.com/item/...

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Very nice link Mark.  Thanks

 

Jim

If you want a career with a known path - become an undertaker. Dead people don't sue! - Kartman

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB user

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MarkThomas wrote:
I have been using the following DC-DC buck converters for a while and they seem to be quit stable and are able to put out 1.7A continuously.  They are quite small.

 

https://www.aliexpress.com/item/...

Thanks Mark. I notice it says Seller Guarantees on-time delivery of 60 days, how long is the actual delivery time to SF?

 

Judging from the picture, I suppose you touch up the solder a bit too, or are they usually better than what is shown?

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MarkThomas wrote:

I have been using the following DC-DC buck converters for a while and they seem to be quit stable and are able to put out 1.7A continuously.  They are quite small.

https://www.aliexpress.com/item/...

 

The title states LM2596 but the photo shows MP2307.

Which chip is used in the module you received?

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... which it appears to call the "New LM2596".

 

Ross McKenzie ValuSoft Melbourne Australia

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"Dare to be naïve." - Buckminster Fuller

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Yes, the chip says MP23070N.  I think the soldering is better than in the picture.  I noticed in the picture one of the caps is in sort of crooked.  Mine all look nice.  As for everything from AliExpress, the delivery is between 2 weeks and two months.  I ordered those quite some time ago and I dont remember if they were one of the longer times.  I think they came pretty quick for AliExpress.  Maybe a month or so.

 

I've used the MP1584 boards too, and they seem to work about the same.  The smaller boards get pretty warm passing an amp or more with input of 6V and output 4.2V.  I think the larger ones do too, but I switched to the smaller ones when I found them.  I've had one running for about a year driving an LED lamp at 1.1 A and 4.2V with an input of 6V from a wall wart.  The output voltage has held steady at 4.20 V the whole time.  It is sort of amazing you can get something like that for $0.50