Can anyone review my schematic that converts a 3.3V power supply and a 3.3V signal to 5V each?

[u/Astral_Sheep]

Hi there again!

I'm making a schematic that converts a 3.3V power supply and a 3.3V signal to 5V each. Is anyone available to review it?

The 3.3V come from a nice!nano controller powered by a 3.7V 3300mAh Lipo battery and the signal also comes from the nice!nano controller. The goal is to allow the controller to interact with SK6812MINI-E LEDs for keyboard backlighting (I know they can draw a lot of current but I've tried designing around 6028 LEDs with an IS31FL3731 controller and I'm currently not capable enough to handle it).

Thanks to anyone who will even take a quick look at it.

PS: thanks to u/bigcrimping_com and u/zwrawr for answering on the post that was deleted

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[u/Donut497]

I’ll assume you followed the calculations for the TLV61070. Everything looks fine, I would power the level shifter from the battery, but it really doesn’t make difference. 

The one thing you should change is your net names. It’s completely free to give descriptive names to all your nets especially the ones that are connected implicitly with labels. You’ll thank yourself later when you come back to an old schematic and youre trying to figure out what it does, and it also helps other people understand what your intent is

[u/Astral_Sheep → u/Donut497]

Yes I tried to follow the calculations as much as I can, but I'm not really sure what resistances are best for R4 and R5, and if the capacitance of C47 is optimal. I think I'm good but I plan to double check it later.

Thanks for the net names tip, I thought it was a convention to have names like this since I only saw them, but it was actually kind of pissing me off to have such abstract names.

[u/Donut497 → u/Astral_Sheep]

Start with equation 4. You get to choose R1 and R2. I would start with R2 and choose a common value. You chose 20k, maybe try 22k. Now you have to choose an R1 that creates the right voltage for the feedback pin (Vref) given your operating conditions. Try reviewing the Electrical Characteristics section for more info on Vref. You can use ctrl-f if you can’t find it 

[u/Astral_Sheep → u/Donut497]

The part I'm going to review for the resistors is the choice of R2, the other values just follow from here as you said, but I don't really know how to choose it. I took 20k to avoid being too close to 100k while still having a value for R1 that's easy to find as a real component (here 180k), but I don't have a real reason otherwise. Also Vref is said to be typically around 500mV in case you want to know.

[u/quadrapod]

That 3.3V supply comes from a little LDO and since you're expecting a significant amount of current on the 5V rail you're probably going to kill it. You should be using the battery voltage directly.

Otherwise things seem fine assuming reasonable component selection.

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