I’m going to use a Rumba32 board with 6 TMC2209 drivers. The board will be always connected via USB to a PC and powered by a 24V source via MAIN-PWR connector.
I see that +5V and VMOT are tied by a 40V, 2A, diode. So if VIN fails, +5V rail powers VMOT. I’m worried about that because the board could try to drive current to the motors from +5V, powered by USB (PC). Is this situation safe or better remove the diode and cut the connection between +5V and VMOT?
I have worked with TMC drivers previously and always I have independent planes/sources for VCC_IO and VS (VMOT) and when VS falls but VCC_IO maintain +5V (and microcontroller keeps sending steps) I never had a problem with the drivers.