I have a Raspberry Pi 4 that's is powered on the USB port by a circuit I made. The key component is a Buck Regulator (LM2576-5.0WT), the input is a AC adapter (12 V - 8 A). The regulator is able to provide the 3 A required by the Pi (in 5 V).
But when I plug the RPi, the power LED turns on, but not the ACT one. When I check the tension, it's 5 V without the Pi and 6.9 V with it. And, when I check the current, it is 0.3 A, of course not enough to switch on the Pi.
So I thought it was my power circuit the problem, but when I plugged a motor instead of the Pi, it could go to 2 A (I have to find other loads to go up the 3 A). But, is there something that could limit the Pi to 0.3 A?
Thanks in advance for any clue.