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DRV8301: Current limiting tolerance in DRV8301

Abdulrahman
Prodigy 20 points
Part Number: DRV8301

Hello,

In the datasheet of DRV8301 http://www.ti.com/lit/ds/symlink/drv8301.pdf , it is written under "Overcurrent Protection and Reporting (OCP)" section:

"There can be up to a 20% tolerance across channels for the VDS trip point"

The question is: as I want to limit my motor current to 2A and I want to limit it exactly to this value in order to use maximum torque possible, is the above method is reliable?

In other words, is the tolerance is because there are limited values for Vds threshold (see table in p23) ? or whatever the value I choose from the table is to have that tolerance?

If you have better way of limiting the current accurately using DRV8301 on-chip resources, please suggest it

Thanks

  • 0
    TI__Expert 4650 points
    Hello user4902512,

    The 20% tolerance is for each VDS trip point. Whatever value you choose from the table will have a 20% tolerance on that value. The VDS trip is intended as a Worst Case net to stop over current events, not as a high-accuracy current limit path.

    The most accurate way to limit current would be to use the current shunt amplifier outputs tied to an ADC on an external MCU. The MCU can then make a decision on how to change the INx channels to react to the measured current in the system. If you only need to monitor the sum of currents in the motor, you can use one current sense amplifier and a single current sense resistor.
  • 0 in reply to Phil Beard
    Prodigy 20 points
    According to my application and my view, I think it would be better if there was a comparator-like limiting option implemented on hardware.

    Thank you for help.