That won't work. Q8 is a P-channel mosfet, so it allows 3.3V through when its gate is at ground level. Meanwhile, Q7 will ground that gate when 5V is applied; so you're getting the exact opposite behavior compared to what you intended. You probably want to remove Q7 and connect D4 directly to the ...

Hello everyone.

I want to power an ESP32 S3 Zero with an external 3.3V power supply when it is not connected to the USB. According to the schematic, the USB has no protection, so I must connect a Schottky to the 5V pin myself.

My idea is to isolate both 3.3V and allow the external 3.3V only when ...