I'm wanting to build a circuit that will boost a 18650 battery to run a ATTINY85 at 5v/16mHz. Does this look sufficient, or is there something better?
I use these modules. They have the charger, boost converter (adjustable) and protection circuits for the 18650 battery.
Shame it doesn't have a schematic.
I can't fit two PCBs, so I'll have to try to find a schematic somewhere.
Looking at your other thread, it looks like you're sending 5V to what I thought was a 3.3V OLED display. Could you check that? If the display only needs 3.3V, and if you could run the 85 at 8MHz, then you could just use a 3.3V LDO, which would give you a much simpler circuit. You would need an LDO with a dropout voltage under 200mV.
But if you need the boost converter, that module is just a TP4056 followed by an MT3608. You can get the schematics from the Typical Application sections of the datasheets.
Edit: That module is 3.5 x 2.5 cm, and includes a microSD socket. Your circuit isn't going to be any smaller than that, and designing SMPS layouts can be challenging. If you need these functions at all, I'd suggest you use the module if you can.
I don't think they have protection circuits. At least the one I have doesn't.
I thought that the ones that I linked had protection circuits, but now I will check to confirm that. It is a bit alarming if they don't as I have several projects using them.
No, it's the J5019 module, and you can see in the picture that it has only the TP4056 and the MT3608. No DW01 or dual mosfets. So there's no protection.
Thank you for letting me know. From now on I will make sure that the batteries have built in protection or source better chargers.
I originally bought them to charge some flat LiPo batteries that had protection circuits. I guess that I did not think when I decided to use them for some 18650 charging. I will buy some protection circuits for those batteries.
I've been looking at the Adafruit PowerBoost500. It seems really good to me.
I will only be using protected cells, so it should be fine.
The Adafruit module is more efficient than the J5019, but it's a lot more expensive, and it's showing as out of stock.
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Yeah, I don't have space for it either, so I'm building it into my PCB using their schematic.
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