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Electronics => Power & Renewable Energy => Topic started by: wb0gaz on April 10, 2021, 01:36:58 pm

Title: Need suggestion - boost converter (module) - nominal 3.7v in, 12v out, ~25W max
Post by: wb0gaz on April 10, 2021, 01:36:58 pm
Looking for suggestion for a boost converter module - my application needs to power a 12V class device from a single 3.7V Lithium Polymer cell, peak load about 25 watts, no load open circuit, with undervoltage shutdown (to avoid overdischarging the LiPo cell) and no load/transient output voltage limited to the application voltage (12V).

Would prefer a module vs building from components, but open to that if no module option available.

Thanks for any suggestions; clarifying questions (I'm sure I've left out important details, but need to start somewhere!) welcome.

PS I realize 25 watts (+ efficiency overhead) is alot from a single Lithium Polymer cell - I'm thinking 10000 mAh cell for this application.
Title: Re: Need suggestion - boost converter (module) - nominal 3.7v in, 12v out, ~25W max
Post by: Algoma on April 10, 2021, 02:29:02 pm
Is it a momentary burst draw like a trail camera, or more continuous current draw?
Title: Re: Need suggestion - boost converter (module) - nominal 3.7v in, 12v out, ~25W max
Post by: wb0gaz on April 10, 2021, 03:11:19 pm
Algoma - it would be a mix in terms of demand profile - 25 watts continuous up to about 1 minute, average duty cycle up to 50%, or any parameters below those limits.

Blueskull - I have initially surveyed boost converter modules on ebay (practically all sourced from China); I ordered one type (262450277951 item ID) for initial experimentation (it would not likely meet the 25W output requirement), then realized it's listing has a warning in the details of the posting about exceeding output temporarily during no-/low-load condition (which would be a damage risk to the application.)

"Module at no load and off load easily start momentarily output voltage exceeds a preset voltage, it is not suitable for voltage sensitive equipment."

I could not find any modules during my survey that specifically claim under voltage lockout. I surveyed 2A-5A class boost converter moduies with <3.0V minimum input voltage and >=12.0V minimum output voltage. Several warn (either in the listing details or during review messages) of exceeding specified output voltage under transient conditions.

I do not specifically require short circuit, reverse polarity or current limiting protection, undervoltage lockout could be worked around, however, any of those features would be useful (else need incorporate that in my application.)
Title: Re: Need suggestion - boost converter (module) - nominal 3.7v in, 12v out, ~25W max
Post by: wb0gaz on April 10, 2021, 03:26:40 pm
Thanks, Blueskull --- I surveyed briefly "power bank"; it seems there are some that use 6x18650 cell, however, output seems limited - 12V 0.6A, which is ~30% of required power delivery during discharge. Do I read the claim wrong? I think 18650 cell each supply >0.6A even under CDR conditions?
Title: Re: Need suggestion - boost converter (module) - nominal 3.7v in, 12v out, ~25W max
Post by: wb0gaz on April 10, 2021, 03:38:00 pm
Thank you again Blueskull - very helpful!

II did not hear about PD standard before - short reading about PD3.0 is interesting. Without client device (such as laptop computer or cell phone), is it possible to cause 12V output? Does this require intelligent/compatible device to exchange protocol via USB?
Title: Re: Need suggestion - boost converter (module) - nominal 3.7v in, 12v out, ~25W max
Post by: wb0gaz on April 10, 2021, 03:46:05 pm
OK - I will study now trigger device - another type of device I did not learn about until now!

Thank you very much - I am happy for all of your advice!

Dave