QT PY 5v output capability

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movsesk
 
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Joined: Tue Nov 22, 2022 4:49 pm

QT PY 5v output capability

Post by movsesk »

Hello,

I don't believe this is a published spec, so I will ask here.

I am looking at using one of the QT PY boards in a project run, approx 100-200 pcs. Likely will use the ESP32-S3 variant. I came to realize I may be able to use the QT board to power my project as well from the 5v output. This will save me from having to put another power input jack on the PCB.

My question is.. if I solder the QT board onto my own and use the 5v output. How much power can I safely and reliably use from the castellated/through-hole pcb conection on the QT?

My specific project uses about 5v 800ma on average but may peak at 1-1.0A. This is not counting the QT power.
I don't have a QT board on hand yet.. but I've looked at the basic design near the 5v pin and most of the QT boards look similar, appears to run through a diode. The traces are short, so that should not be a problem. I guess one specific question would be the rating of that diode (if 5v is actually going through one). If any of the USB connector power pins are not connected, that may be a limit too.

Thank you for the assistance!

Regards,
-Moses

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mikeysklar
 
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Joined: Mon Aug 01, 2016 8:10 pm

Re: QT PY 5v output capability

Post by mikeysklar »

Moses,

The Power section for the Qt Py ESP32-S3 addresses your concerns. 500mA recommended and 1A max for the diode.
You can also use the 5V pin as a voltage input but you must have some sort of diode (schottky, signal, power, really anything) between your external power source and this pin with anode to battery, cathode to 5V pin. Note that you cannot power the USB port by supplying 5V to this pin: there is a protection diode that prevents the 5V from reaching the USB connector (unless you bridge the jumper on the back!). This is to protect host computer USB ports, etc. You can draw 1A peak through the diode, but we recommend keeping it lower than that, about 500mA.
https://learn.adafruit.com/adafruit-qt- ... er-3119648

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movsesk
 
Posts: 7
Joined: Tue Nov 22, 2022 4:49 pm

Re: QT PY 5v output capability

Post by movsesk »

Mikeysklar,

Thank you for the quick reply!

I didn't see anything under technical details and I completely missed the "Primary Guide" link on the products page!

Good info.

Regards,
-Moses

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