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PowerBoost 500 Charger backfeeding
Moderators: adafruit_support_bill, adafruit

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PowerBoost 500 Charger backfeeding

by JUehV on Wed Aug 14, 2019 7:19 am

Hi,
I'm powering my mobile Raspberry Pi Zero with a PowerBoost 500 Charger. So now I'm wondering if it is an issue when the Pi gets power from its USB ports (because I want to use it in gadged mode sometimes). I worry in a worst case current would flow back in the board and damage something. Or is there already an protection ?

Cheers!

JUehV
 
Posts: 2
Joined: Wed Aug 14, 2019 7:16 am

Re: PowerBoost 500 Charger backfeeding

by adafruit_support_bill on Wed Aug 14, 2019 7:25 am

The output pin of the boost converter is rated to tolerate up to 7v (Absolute Maximum rating). Though it is not a recommended operating condition, it should be OK. You could add a diode on the 5v line between the Boost and the Pi for best protection.

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

Re: PowerBoost 500 Charger backfeeding

by JUehV on Wed Aug 14, 2019 7:40 am

Thanks you so much for that fast answer!

adafruit_support_bill wrote:You could add a diode on the 5v line between the Boost and the Pi for best protection.


I thought about a diode too. But with the high power consumption of the Pi, the small voltage drop of the diode results in a non-negligible power loss :/

JUehV
 
Posts: 2
Joined: Wed Aug 14, 2019 7:16 am

Please be positive and constructive with your questions and comments.