💬 Buck Energy Harvester
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Woa, congrats on posting project #400 on openhardware.io!
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The credit goes to you guys for creating a worthwhile place to post things. Keep up the good work!
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The version 1 bottom silk screen had some errors, which I have corrected and posted as version 2. Also, I cleaned up the schematic to make it more readable.
For the initial test board, I used one of the inductors prescribed by the datasheet. Using zero ohm resisters instead of the 10K resistors should yield exactly the same as the sample application in the datasheet. Yet, it is not working. At present I'm unsure as to why, but I will continue troubleshooting it.
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I think I found the fatal flaw: I didn't account for so-called "Pin 11", which is a GND pad directly under the chip. On my first reading I had thought it was there purely as a thermal pad, but it apparently requires electrical connection to circuit GND. Fixing this will require a re-design and a new PCB to be fabricated.
Ordinarily this kind of chip would require re-flow soldering. However, to retain the option for hand soldering, I'll try creating a large diameter through-hole under the chip so that the connection can be hand soldered from the opposite side of the PCB.
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I notice that there are now large parts databases with free downloads for a lot of electronic chips and components. These seem to be a recent development. I notice, for example, that I'm now able to download a free model for the LTC3388 from snapEDA to some of the more popular PCB cad packages without having to build it by hand. Mainly for that reason, I'm switching from Diptrace and now learning Kicad, which itself seems to have changed (well, at least its UI) quite a lot over the last year.
For anyone else who wants to do the same, there's a 2 hour tutorial on Kicad that's free: https://www.youtube.com/watch?v=BVhWh3AsXQs that seems like an easy way to quickly learn Kicad. So far, so good, and I've just now completed importing the snapEDA part definition for the LTC3388.
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I just now posted Version 4, which fixes the earlier problem and which I created in Kicad as my first Kicad project.
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@neverdie Nice work - I have been follwoing this quietly since it first appeared.
Will you be selling pcbs for this? I'd like to try it next year (sooner if the chip price drops!). ;)
Also of note is the KiCad is FREE ! :)
@skywatch After I've verified with a successful build that the fabricated PCB works as intended. I sent the files to OSHPARK, so it will be a few weeks before I receive the PCB for testing.
I'll try Kicad some more, but so far I feel as though I can work much faster using diptrace.
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All done! It works. I made some corrections to the silk screen, so everything should now be in order. :-)
