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DRV8881EEVM: Current limit setting on GUI

masahiko shimizu
Guru 11235 points
Part Number: DRV8881EEVM

Hi,

Could you give me your advice on how to set linear chopping current on GUI, please?
GUI can selest chopping current value from pull down menu of "ICHOP".
But this value of increment is by 125mA.

For example, My customer confirm motor operation at 340mA full chopping current.

Best regards,
Shimizu

  • 0
    TI__Guru** 114905 points
    Hi Shimizu-san,

    The GUI and firmware is a compromise to show how the device can operate using high levels of microstepping.

    A lookup table was used for the sine table and simple math was used to create the percentanges of current.

    To achieve 340mA of current, change:
    1) both sense resistor such that 340 mA is a percentage of the full scale current (277mOhms OR
    2) cut the path from header pin 7 (8xV3P3) to the DRV8881E and connect your own voltage reference at the top of the DAC (header pin 7). You would need approximately 3V.

    I would recommend option 1. It has been some time, but I think the chopping currents are re-calculated when the new resistor value is placed in the SENSE resistor box. The values will not be re-calculated if the voltage at header pin 7 is changed.