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I have an H-bridge motor driver board. The Vcc & GND of the same is also connected to a microcontroller, MOSFET driver and, other electronics. The power supply to the motor driver board has an XT60 connector and the small DC motor is connected through an XT30 connector.

What would happen if both had the same connectors and by accident, they were switched, i.e. the supply is connected to where the motor should have been and vice versa?

Would there be catastrophic damage, or would the MOSFETs just act as open switches because there won't be any power to the microcontroller and the MOSFET driver to turn the MOSFETs ON?

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  • \$\begingroup\$ That cannot be answered without more information. It is like how long a bridge bridge needs to cross a river. Unless you know how wide the river etc is it cannot be properly answered. Model, part numbers, and links to technical information on the parts involved helps us help you. \$\endgroup\$
    – Gil
    Apr 15, 2023 at 3:18

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I doubt there would be no consequences, due to the FETs' body diodes. You may think the FETs are off, but they can conduct anyway via those diodes, from drain to source, regardless of the state of the gate.

I couldn't say if it would be catastrophic, there are too many variables. I can give you an idea of how it's likely to be bad, though! Just follow the red current path, via the body diodes of MOSFETs which are forced "off":

schematic

simulate this circuit – Schematic created using CircuitLab

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