DRV8872: nFAULT pin will Low voltage level

Kevin Huang8

Part Number: DRV8872

Hi Team,

nFAULT pin will Low voltage level when the Motor rotates (UVLO/OCP/TSD will not have this state), is it because of inrush current?

over 2 years ago

0 Pablo Armet over 2 years ago

TI__Mastermind 37683 points

Hi Kevin,

Can you provide a waveform screen capture showing motor voltage, current, and nFAULT line? This will give me a clue as to what fault is causing the nFAULT to go LOW.

Regards,

Pablo Armet

0 Ryan Kehr over 2 years ago

TI__Guru 55645 points

Kevin,

It could be OCP. Do you see the device try to restart in 3ms (Tretry time)? That is a good indication that it is OCP.

Regards,

Ryan

0 Kevin Huang8 over 2 years ago in reply to Ryan Kehr

Genius 4676 points

Hi Ryan,

Please refer to the circuit diagram, current waveform diagram, and DRV8872 oscilloscope waveform.

0 Pablo Armet over 2 years ago in reply to Kevin Huang8

TI__Mastermind 37683 points

Hi Kevin,

It does look like an OCP fault. When an OCP fault occurs, the output will be Hi-Z for t_retry (3ms) which seems to match the time in the waveform. Could possibly be because of inrush current. Will have to take a look at the output current to confirm.

Regards,

Pablo Armet

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DRV8872: nFAULT pin will Low voltage level