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DRV8870: Periodic Sleep Mode / Max Output Capacitance

Keith Nicholas
Mastermind 46560 points
Part Number: DRV8870

Hello,

I have a few questions regarding the DRV8870 driving a 24V motor.

1.  Expect to put motor driver in Hi-Z state on a periodic basis, +10Hz or higher rate, which will place DRV8870 into sleep mode.  Are there any concerns in using the DRV8870 where it constantly goes into and out of sleep mode?

2.  Plan to use noise filtering capacitors up to 10nF on OUT1 and OUT2.  Will this effect reliability or cause any other issues?  According to the datasheet, the OCP will not trip for 1.5uS, which is much longer than the expected current charging spike.  Is there a maximum peak current/time that needs to be observed for the internal FET's?

Thanks,
Keith N.
AFA OH/wPA

  • 0
    TI__Guru** 114905 points
    Hi Keith,

    1. Expect to put motor driver in Hi-Z state on a periodic basis, +10Hz or higher rate, which will place DRV8870 into sleep mode. Are there any concerns in using the DRV8870 where it constantly goes into and out of sleep mode?

    No concerns. Will the motor be driven in both directions?

    2. Plan to use noise filtering capacitors up to 10nF on OUT1 and OUT2. Will this effect reliability or cause any other issues? According to the datasheet, the OCP will not trip for 1.5uS, which is much longer than the expected current charging spike. Is there a maximum peak current/time that needs to be observed for the internal FET's?

    If the peak current is less than 3.7A for 1.5us, this should have no effect on reliability. If the capacitors can be reduced, this will help with overall efficiency since the capacitors are not constantly charge and discharged.