Alright, I've replaced the 10 Ohms gate resistor with a 100 Ohms one and it solved the issue I had at low duty cycle while also getting rid of the ~MHz ringing I had with the 10 Ohms resistor. Thanks @Antonio51 for the advice.
Here is a video of how the gate voltage looks like now (without and then with the motor connected) : https://drive.google.com/file/d/1fhwfmat0HiVCM04DbWdiIYtffUbRr9q1/view?usp=share_link
Here is the shape of the rise waveform (6.380 µs rise time) :
Here is the shape of the fall waveform (7.020 µs fall time) :
For a total rise and fall time of 13.4 µs. Against a period of 500 µs, that's about 2.7% of the period. There is some small ringing on the fall waveform, I don't know if it's concerning or not.
Here is a picture of my physical layout :
Conclusion and next steps :
So now it works as intended, but there are many things I want to improve, mainly because the motor will be loaded (certainly a lot) in the future, which means much more current going through the MOSFET and I'm mainly worried about heat management :
- Reduce the rise and fall time to under 1% : add an intermediary gate driver stage using a part like these : TC4422 or IXDN604
- Make the driver-gate and ground-source wires as short as possible and much thicker (as I've read many times now that they need to be "short and strong")
- Replace the NE555 by a TLC555 for reduced power consumption
- Use a large CPU heatsink with integrated fan for the MOSFET instead of my homemade one
- Use a second MOSFET in parallel to improve heat dissipation; I don't really know if the gain from this one would be worth the trouble
Could you please give me your advice regarding these improvements ?
Do you think they are relevant/good ideas ?
Which one would have the most impact regarding heat management ?
Thank you all for your time and replies, this has been a wonderful learning experience for me, and slowly working towards a functional and robust solution for this is a genuine joy.
Have a nice day !