Powering a Tiny Arduino Project

Question

I'm trying to build a tiny project. After I program the board, to power the dev board - how can I power it to run the code?

Question:

• I was curious as to how I would be able to power the ATtiny85 USB Mini Dev Board by using a 90mAh 3.7V LiPo battery which is connected to a TP4056 5V micro USB Lipo battery charger? The power is regulated to 5V by a 3v to 5v 1a USB Charger DC-DC Converter feeding the 5V pin on the ATtiny85.
• If now, how else can I power the ATtiny85 USB Mini Dev Board with a rechargeable battery?

New Circuit

Old Circuit

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Final Circuit

Answer 1

The old circuit will not work as you expect. While the ATtiny85 can run happily with 2.7 to 5.5V in this setup it expects 5V. I assume this is due to the high CPU clock setting. To run stable at a high CPU clock it requires 4.5V.

The VIN pin is connected to a linear regulator that has a 2V drop-out. Thus the supplied voltage has to be at least 2V about the target voltage. That is why the shopping page states a 5V (direct) or 7-35V (regulated at VIN) power supply.

Your LiPo charger already has a boost converter built in that boosts the battery voltage (3.0 - 4.2V) to 5V. No need to use a separate DC-DC boost converter here.

Just connect OUT+ to 5V and you are done.