3.3v on QWIIC PiHat not connected?

Qwiic System
1

On the QWIIC PiHat adapter the 3.3v through hole connector is connected to the 3.3v of each of the 4 ports, however it is not connected to the 3.3v on pin 1 or pin 17 of the Raspberry Pi GPIO header when I did a continuity test. Looking at the board, it looks like there is a voltage regulator(?) that takes 5V from the pi and and steps it down to 3.3v.

Is this because 4 devices running on 3.3v could potentially draw more current than the pi can provide from it’s 3.3V power bus?

2

That’s a a safe assumption…don’t want to cook it! Also, qwiic devices run on 3.3v, so this ensures it’s stepped down when using the 5v pin

Hope this helps!

3

Just to add to what TS-Russell said, older models of the Raspberry Pi can not source much current from the 3.3V pins, hence the regulator.