USB-C Boost Buck Box
This is a box I made myself as the easiest way to have a reasonably powerful portable DC power supply with both continuously variable voltage and current limiting. It takes advantage of the fact that USB-C chargers are at this point ubiquitous so there is no need for dedicated AC to DC adapter hardware. I can give myself low-current 20+VDC off my laptop, or ~80 watts off higher-end USB-C bricks.
It takes a USB-C power input via a module and can accept 5, 9, 12, 15, or 20VDC (Amazon link to the one I used, ~$18/2 as of writing). Alternatively you can supply power via the banana plugs (selected with the switch on the left). It then routes this to a Boost-Buck module (Amazon link, ~$25) that outputs up to 80W from 0-36VDC and 0-5 amps to the banana plugs on the right (with a hardwired on-off via the switch on the right). I designed and 3D-printed the housing.
It works great. It’s small, portable, and has enough power and flexibility to hot-wire children’s toys when you don’t have the correct DC batteries to testing equipment. It is particularly useful because you can see the current / wattage so you know immediately if there is a draw and if it seems too high or low.
Here are some more images of it.
More CAD Renders
Real Life Photos
There are a few areas for improvement if/when I revise it.
It would be nice to have multiple outputs, especially without dramatically increasing the size. I may use a voltage regulator to give myself a second, lower voltage output off the main output. If I used an LM338 then the second output would be limited to 3VDC or more below the main output (probably fine) and it probably wouldn’t have a display, but a 10K pot would map nicely to 0-100% of a 20VDC max. That would give me the option of having, e.g. a 12VDC and a 5VDC in one box. Or I might make a completely separate box with several regulators I can use for multiple AUX outputs.
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