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Disable Charging Circuit on Feather?
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Disable Charging Circuit on Feather?

by GoremanX on Sat Feb 15, 2020 12:24 am

This took me WAY too long to figure out, but I've finally found the source of my issues. I'm using a Feather 328p and Music Maker featherwing, which sends an audio signal to a separate speaker amp.

When powering the Feather via USB with no battery attached, the charging circuit pulses rapidly (presumably because it expects a battery to be there). This pulsing causes a lot of noise on the ground of whatever circuit the Feather is plugged into. In my case, this ground noise is finding its way into the external speaker amp that's connected to the same power source. No amount of grounding trickery or re-routing completely eliminates it. I'd much rather eliminate the noise altogether by not having it happen in the first place.

There's no way to power these components using different power sources. Is there any way to disable the charging circuit? Or could I power the board with 3.3v directly through the battery port, instead? (and make sure I never plug anything into the USB port as long as the board is powered through the battery port)

GoremanX
 
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Joined: Sat Jan 04, 2020 6:42 pm

Re: Disable Charging Circuit on Feather?

by adafruit_support_bill on Sat Feb 15, 2020 8:01 am

If you have a regulated 3.3v source, you could power the Feather directly via the 3.3v pin. Just do not plug anything into the USB or JST ports when powered that way.

The only other option is to cut a trace or physically remove the charge controller chip from the board.

adafruit_support_bill
 
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Joined: Sat Feb 07, 2009 10:11 am

Please be positive and constructive with your questions and comments.