Charactersitics of a Small Buck-Boost Convertor

RE: Charactersitics of a Small Buck-Boost Convertor

jw0752 — Fri, 22 May 2020 14:27:17 GMT

Hi Dubbie,

I have had a lot of fun working with these little DC to DC converter modules. I enjoyed your blog on the experiment and I hope you post how the module works out for your robots.

John

RE: Charactersitics of a Small Buck-Boost Convertor

genebren — Fri, 22 May 2020 14:12:09 GMT

I have done some experimenting with boost converters, using Li-Ion batteries (and some LiPo). It is possible to achieve higher efficiencies, but a lot of this has to do with component selections. Here are some links to my blogs on the subject:

Choosing the correct Inductor for a DC-DC step-up regulator - Introduction

Choosing the correct Inductor for a DC-DC step-up regulator - Part 2

Choosing the correct Inductor for a DC-DC step-up regulator - Part 3

Walky the Biped Robot - Power pack

Good luck with your experiments/projects!

RE: Charactersitics of a Small Buck-Boost Convertor

shabaz — Fri, 22 May 2020 13:03:03 GMT

Hi Dubbie,

Just to throw another idea out there, it could be an option to operate from two cells, i.e. operating from circa 7-8.4V rather than a single LiPo, and then have a single buck converter (or even just a linear regulator if the microcontroller doesn't need much power) for 5V. The motors could operate from the battery voltage in that case, if they can operate over that voltage range. If they cannot and require 6V then a 6V buck regulator could be used, but often motors mention they are operable from (say) 4.5V-12V or similar, i.e. they will work over a large range. Also a fuse would be good in case of stall, although the battery may have some protection. Plus, good wiring, because the cells can output loads of power, easily melting insulation.

If you required a battery pack with two cells, possibly the radio-controlled model world may already have that, otherwise another option could be a camera battery, some are low-cost. Making contact with the terminals might need some McGuyvering though. As one idea, for a project I ended up buying a 'battery converter' for camera batteries (it is just a holder with metal tabs), intended to adapt the camera battery to fit a charger. My enclosure had plenty of space so I just directly soldered to the battery converter box, it ended up being really easy.