• State Resolved
  • Replies 4 replies
  • Subscribers 29 subscribers
  • Views 60 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

DRV8876: Does Parallel capacitor required to drive the simple DC motor using DRV8876

Murali C
Prodigy 170 points
Part Number: DRV8876
Other Parts Discussed in Thread: DRV8231A,

Tool/software:

Hi Team,

I'm using DRV8876PWPR driver IC to drive the 6v DC motor and operated by 8.4 to 6V (2S1P) battery. Using datasheet, I have implemented the below schematics as my design to drive the DC motor.

Motorimage.html.zip

Here, I haven't added any capacitor in between motor line. Kindly suggest me that DC motor required capacitor in parallel or given the diode and ferrites are sufficient to reduce the noise.

Looking forward your quick response!

Thanks 

Murali C

  • 0
    TI__Mastermind 21690 points

    Hey Murali,

    Schematics looks good.  A few comments:

    • The 1k current limiting resistor (R96) on IPROPI is not necessary, you might want to remove that as I am not sure how that will interact with the IPROPI signal. 
    • The output diodes D4/D5/D6/D7 are likely not necessary, consider testing the board without them.  They are fine to be there, but likely unnecessary. 
    Murali C said:
    Here, I haven't added any capacitor in between motor line. Kindly suggest me that DC motor required capacitor in parallel or given the diode and ferrites are sufficient to reduce the noise.

    The ferrite bead is likely sufficient, and you might not even need the ferrite bead.  I recommend testing it without a parallel capacitor between the outputs.  If this is a prototype board you might want to design the PCB with the capacitor and just "DNP" (Do not populate) it so that it isn't there.

    Is this a new design? You might want to look at a newer motor driver such as DRV8231A

    Best,

    Jacob

  • 0 in reply to Jacob Thompson
    Prodigy 170 points

    Hi Jacob,

    Thanks for the timely response!

    R96 - 1k resistor and C81 - 0.47uF added as LPF/RC filter. It definitely not impacting the IPROPI signal, 

    I have added D4,D5,D6,D7 as a additional protection. Thanks for the feedback.

    It is existing design in production, So I'll stick with the same DRV8876.

    Jacob, Kindly enlighten me about not need of capacitor. Does it have any impact on noise reduction and soft start?

    Thanks 

    Murali

  • +1 in reply to Murali C
    TI__Mastermind 21690 points

    Hey Murali,

    Murali C said:
    Jacob, Kindly enlighten me about not need of capacitor. Does it have any impact on noise reduction and soft start?

    It will not have an impact on audible noise.  Output capacitors however will have an impact on EMI (ElectroMagnetic Interference) noise - so if that is important in your application then it might be important to have. They can also help in similar tests like BCI (Bulk Current Injection).  There is no harm in having them there for normal use, they just typically are not necessary. 

    See https://www.ti.com/lit/ml/slyp697/slyp697.pdf#page=26

    Best,

    Jacob

  • 0 in reply to Jacob Thompson
    Prodigy 170 points

    Hi Jacob,

    Thanks for the explanation. Great!

    Thanks,

    Murali