• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Subscribers 30 subscribers
  • Views 363 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DRV8833: What is the maximum value for R_isen

Simeon
Prodigy 20 points
Part Number: DRV8833
Other Parts Discussed in Thread: DRV8832, DRV8830,

Hello,

I'm trying to determine whether there is a maximum value for the overcurrent protection selection resistor R_isen.
In the datasheet for both the drv8830 and drv8832 there is mentioning of a maximum value which would indicate a minimum current to be set as the limit.

In the datasheet for the drv8830 there does not seem to be a mentioning of such a maximum value.
However, these devises seem to have a lot in common otherwise. so, just to be sure.

Is there a max value for said resistance?

Thanks in advance.

Simeon

  • +1
    TI__Mastermind 45445 points

    Hello Simeon,

    Please use a the same range for the DRV8833 as well 0 to 1Ω. Generally the voltage range across RISEN specified must be followed. The DRV8833 can support higher peak currents compared to the other two variants so RISEN should be kept smaller to minimize voltage drop and power dissipation across RISEN. 

    Is there a specific value or reason you'd want to use a > 1Ω resistor for RISEN? Thank you. 

    Regards, Murugavel

  • 0 in reply to Murugavel4637
    Prodigy 20 points

    Thanks for your reply.

    I will not use a resistor > 1Ω.

    The reason was: I want to drive a small dc-motor with a stall current that is significantly lower than 200mA. namely 80mA.
    So that would require me to use a 2,5Ω resistor.

    I will look for a different solution.

    Thanks again.

  • 0 in reply to Simeon
    TI__Mastermind 45445 points

    Hello Simeon,

    Thanks for sharing the details about your motor and its use case. Did you try with a 2.5Ω resistor? Was there any issues? Were you looking for a single or a dual H-bridge driver? 

    Regards, Murugavel

  • 0 in reply to Murugavel4637
    Prodigy 20 points

    Yes, 

    I did try with a higher value resistor and it seemed to work fine. that's why i asked the question in the first place.
    I used a single H-bridge.

  • 0 in reply to Simeon
    TI__Mastermind 45445 points

    Hello Simeon,

    Thanks for the update. I will check with the internal design if there will be any concern with device operation using higher value resistor for RISEN.

    Regards, Murugavel

  • 0 in reply to Murugavel4637
    TI__Mastermind 45445 points

    Hello Simeon,

    The conclusion was, as long as the voltage across the RISEN are within the MIN and MAX of the VTRIP specification using a > 1Ω should not cause any issues. You should be good with it if it supports your application's requirement. Please try to use as small a value the application could permit.

    Keep in mind, a short circuit situation at the output could increase the VISEN to significantly higher than absolute max specifications and permanently damage the device. Using higher RISEN increases this vulnerability. Would be good to use a current limiting power supply to avoid this situation incase of a short circuit at the output.

    Thanks. 

    Regards, Murugavel