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DRV8412: /FAULT behavior in case of overcurrent shutdown with CBC or OC latching shutdown

Hirotaka Matsumoto
Guru 27585 points
Part Number: DRV8412

Hi all

Would you mind if we ask DRV8412?

We would like to confirm /FAULT behavior in case of overcurrent shutdown.
There is the description on Table1.


We assume that it depends on M1～M3 settings.

In case of cycle-by-cycle current limit(M1=M2=M3=0)
->Fault pin is asserted during PWM_HS's low(yellow blocks).


In case of OC latching shutdown(M1=1, M2=M3=0)
->Fault pin is asserted until reset or restart(power on and off toggling).

Is our recognition correct?

Kind regards,

Hirotaka Matsumoto



  • +1
    TI__Mastermind 37683 points

    Hello Hirotaka-san,

    cycle-by-cycle current limit and OC latching behave different even though it may sounds like both techniques limit the current. let me explain:

    CBC current limit has two protection functions. One is limiting the current during initial motor current ramp-up or when the current is above the limit threshold. The image you attached shows how this process works. The device will not go into over-current shutdown and nFAULT will not report a fault. The second protection function of CBC occurs when the output current rise much higher than the current limit such that the current cannot be regulated properly. When this happens, the device will report an overcurrent shun-down fault causing nFAULT to latch LOW require a device reset to unlatch.

    OC latching shut-down will always report an overcurrent fault when the output current is above the threshold set by OC_ADJ. nFAULT will latch low when this event occurs.

    I hope this answers your question.