💬 3.3v Buck-Boost DC-DC Converter

[openhardware.io]

https://www.openhardware.io/view/276/33v-Buck-Boost-DC-DC-Converter

[NeverDie]

I upgraded the breakout board to include the discrete components shown in the schematic on page 1 of the datasheet.

[NeverDie]

I just now posted Version 007, which includes:

1. An improved trace layout that better conforms with the datasheet recommendation for trace placement.
2. A schematic.

@hek
For some reason the rendered PCB images aren't updating. Instead, it keeps loading the renderings from the earlier version.

[hek]

It is probably cloudflare that caches it (our cdn). It should time out at some point.

[NeverDie]

@hek
OK. At least the 3D model is correct. I just added Osh Park renderings as a stopgap until the cache updates for the 2D renderings.

[NeverDie]

I just now posted Version 9.

Changes from Version 8 are:

1. Utilizes shielded 15uH inductor (previous was unshielded 10uH). Much larger footprint than previously, but it has a ferrite core, a low DCR, and a high current rating. The LTC3531 is somewhat vague as to the recommended specs for component selection. So, to narrow down the possibilities, I borrowed the recommendations from the LTC3105 datasheet, which says, "Low DCR power inductors with values between 4.7µH and 30µH are suitable for use with the LTC3105. For most applications, a 10µH inductor is recommended. In applications where the input voltage is very low, a larger value inductor can provide higher efficiency and a lower start-up voltage." The inductor I've tentatively picked is: http://www.digikey.com/scripts/DkSearch/dksus.dll?)Detail&itemSeq=213304934&uq=636162799100075858

2. Utilizes X5R 1208 15uF capacitor (previous was 10uF). According to DS, this should reduce output voltage ripple. http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=213308469&uq=636162799100085864

BTW, for the input capacitor, I'm picking this: http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=213328190&uq=636162859327817001

[NeverDie]

I just posted Version 10. The only change from Version 9 is that I re-aligned the headers so that they'll easily plug into a 2.54pitch breadboard.

[NeverDie]

I tested the assembled PCB, and it works. This project is now finished. :)

[tonnerre33]

Thanks you ;)
But i don't understand the difference between your 3 boost projects :( can you explain to me ? :)

[mfalkvidd]

I'd love to see a side-by-side comparison.

[NeverDie]

Yeah, that would be nice. I did try to differentiate among them a bit by the titles I gave them. Beyond that, I'll have to direct you to the datasheets.

[Marcel Stör]

What is the long/peak time maximum output current in mA this converter can sustain?

[NeverDie]

@Marcel-Stör

Sorry, I don't know. Maybe try the datasheet.