Powering Micro Pro Qwiic from a Li 3.7 battery

Development Boards Arduino
1

I have this Qwiic Pro Micro:

https://www.sparkfun.com/products/15795

By default, it comes set to 5V. I want to power it from a 3.7 Li battery.

  1. I assume I need to cut/solder the solder-jumper to 3V3, since RAW voltage will be 3.7V?

  2. Will Qwiic sensors linked to this Micro Pro work fine after this? I.e. will they get their 5V or 3.3V (whatever they need), regardless whether the Pro is set to 5V or 3.3V?

2

Hi,

1) I assume I need to cut/solder the solder-jumper to 3V3, since RAW voltage will be 3.7V?

If you connect a single cell, LiPo battery to the RAW pin, the system voltage will vary depending on how much charge the the battery has. Nominally, it will be 3.7V but it can be 4.2V fully charged. You can set the ATmega32U4’s I/O to either 5V or 3.3V. Having it on the default 5V, the ATMega32U4 will have a varying voltage depending on the battery’s charge. Setting it to 3.3V, the battery voltage’s will be regulated down to 3.3V. You don’t need to adjust the solder jumper unless you wanted to. Either volotage should work.

2) Will Qwiic sensors linked to this Micro Pro work fine after this? I.e. will they get their 5V or 3.3V (whatever they need), regardless whether the Pro is set to 5V or 3.3V?

If you look at the [Qwiic Pro Micro USB-C’s schematic linked in the Resources and Going Further, Qwiic-enabled devices will take what it needs regardless of what the I/O is set at. Power is connected to the output of the 3.3V voltage regulator via the 3.3V net.](https://learn.sparkfun.com/tutorials/qwiic-pro-micro-usb-c-atmega32u4-hookup-guide/resources-and-going-further)

3

OK, thank you.