Safest way to power a feather from the notecarrier B (or vice versa)

Hardware Notecarrier B
1

Vio seems to be the only 3v3 supply pin on the board and I see on other posts that it is explicitly not designed to provide power to anything. Would connecting the two vbat pins together cause any conflicts with the two battery management ICs? Or maybe I could use the qwic connector?

Alternatively is it better to power the notecarrier and card from the feathers 3v3 supply?

2

Hi @tjw_scion

Powering the Notecarrier B and Notecard from your Feather may or may not be possible depending upon which specific feather you are using and how much it can drive from the 3v3 pin.

Swan can provide 2A through its 3V3 output which would be sufficient to power Notecard, but that is typically not true of most feathers.

VIO can drive 150ma which may or may not be sufficient for your needs.

You may be able to make this work, but to be sure I would recommend you use Notecarrier-F which is able to supply 3.3V to the Feather from a variety of sources (Battery, Solar, USB, V+).

I hope that helps!
mat.

3

Thanks for the reply.

I’m using the adafruit esp32s3 feather which I think has a 500ma regulator so it probably can’t handle powering the notecard plus my application. It’s also going to use too much power to be powered by the VIO pin, unfortunately.

In the datasheet for the notecarrier b it says " applying 2.5-5.5VDC to the VBAT or VMAIN pins" is a viable option for powering it but it also states that VMAIN is output only :thinking:. VMAIN has been left off the schematic so it’s hard to know what it is exactly. Measuring the output voltage it seems like vmain is just vbat with a diode drop which could be useful in preventing conflict between the two charging ICs depending on where the diode is.

Would love to use the notecarrier f but it’s too bulky for my application.

4

How about using one of these? SparkFun BabyBuck Regulator Breakout - 3.3V (AP63203) - COM-18357 - SparkFun Electronics

5

@tjw_scion How do you plan to power notecard and feather? If it’s by battery then the buck wont work but this one will, since it also can operate on lower voltages. Pololu 3.3V Step-Up/Step-Down Voltage Regulator S7V8F3