Looking a the MIT Mini Cheetah there is a precharge circuit that limits inrush current for ~80ms then allows full current. I am curious to why this is needed if the motor drivers do not power on the coils until the motor on command is issued. Could not the motors be turned on one at a time with a time gap between each motor? Is the issue the capacitors on the driver boards?
Shoot through prevention due to undefined gate states?
The MCU needs time to initialize and set the gates.
Just a wild guess.
Cheers,
Valentine
Big capacitors are like a shortcut for a brief moment after switched on. It’s better to wait for voltage(s) to stabilize.
I guess bootstrap-voltage to switch high-side FETs is the most critical.
To avoid MCU trouble, you could add a longer dwell time in the setup code or even hold the reset pin down during precharge.
That would be my assumption… depending on your power supply and type of bulk capacitance you may want to limit the initial “inrush current”.
If you look up “inrush current” you’ll find lots of resources on it and also many parts available that account for it - like buck converters with extra pins to let you limit this current when they power up.