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Original question:

DRV8833: Output current accuracy

DRV8833: Current regulation tolerance

Benny Ahlqvist
Prodigy 20 points
Part Number: DRV8833

Tool/software:

Hi, what is the distribution of the +/-20% error in the current regulation? Is it also dependent on temperature or just sample size? 

If I have set R = 0.1 ohm then I can have 1.6A min or 2.4A max. But 2.4A overlap the OCP so it get pointless in that range. It seems that this current regulation is optimized for smaller currents?

/Benny

  • 0
    TI__Expert 4730 points

    Hi Benny, 

    Thank you for your question. 

    Benny Ahlqvist said:
    what is the distribution of the +/-20% error in the current regulation? Is it also dependent on temperature or just sample size? 

    There is no information on this.  The specs are evaluated on different operating points with high number of samples. TI guaranties that the specs do not exceed the max and min values.

    Benny Ahlqvist said:
    If I have set R = 0.1 ohm then I can have 1.6A min or 2.4A max. But 2.4A overlap the OCP so it get pointless in that range. It seems that this current regulation is optimized for smaller currents?

    This device is not a good candidate for this condition. Since, it can deliver up to 1.5-A RMS, 2-A Peak. Setting R at 0.1 ohm will set the I trip at 2 A which is equal to  the minimum IOCP is 2 A. 

    Please let me know if you need assistance to find a right product for your appellation. 

    Best regards.

    Mojtaba.

  • 0 in reply to Mojtaba Afshar
    Prodigy 20 points

    Hi, thanks for quick answer. Then if I remove the current regulation function it would be safe just to use the OCP limit in the DRV8833? Does it change anything about EMC if we just change the R = 0.1ohm to R = 0.0 ohm? Or do we need to re-test our design if it passed last time and we just change this resistor? Any thought on that is welcome.

    Best regards

    Benny

  • 0 in reply to Benny Ahlqvist
    TI__Expert 4730 points

    Hi Benny, 

    Benny Ahlqvist said:
    Then if I remove the current regulation function it would be safe just to use the OCP limit in the DRV8833?

    This device can deliver up to 1.5-A RMS, 2-A Peak with minimum IOCP equals to 2A. If the load takes up to 2A, this device is not a good option, since it is higher than the RMS value and also may cause enabling OCP.

    Benny Ahlqvist said:
    Does it change anything about EMC if we just change the R = 0.1ohm to R = 0.0 ohm? Or do we need to re-test our design if it passed last time and we just change this resistor?

    The EMC, EMI depend on the current and Frequency. If the current is increased compared to your previous test condition, you can tedo the test. 

    Please let me know if you have any more questions. 

    Best regards, 

    Mojtaba.