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DRV8231A: IIPROPI max sensing current

Amber Si
Intellectual 1140 points
Part Number: DRV8231A

Hi team,

I found IIPROPI peak current is recommended 3mA in DRV8231A datasheet, So as AIPROPI is 1500uA/A, Does it mean DRV8231A only can sense 2A motor current? but datasheet says output current can be up to 3.7A.

Regards,

Amber

  • 0
    TI__Genius 9230 points

    Hi Amber,

    The 3.7 A refers to the maximum peak current the driver can achieve before reaching Overcurrent Protection threshold, OCP. Exceeding this threshold for short periods of time will not damage the device, but it will cause OCP to activate and disable the output.

    It is recommended to set your RMS or DC current well below this OCP threshold. The current chopping threshold, ITRIP, will allow you to set a threshold below OCP to limit the output current in case of motor stall, high torque, or other high current load events. 

    The following formula can be used to set the ITRIP threshold:

    There are more factors that come into play regarding current ratings such as temperature, power dissipation, and PCB board design. 

    To understand more on TI's motor driver current ratings please see the following application note:

    Understanding Motor Driver Current Ratings 

    Best,

    David

  • 0 in reply to David Medis
    TI__Intellectual 1140 points

    Hi David,

    I want to know about IIPROP of sensing current level, not OCP current or Itrip. Pls see my preliminary questions:

    I found IIPROPI peak current is recommended 3mA in DRV8231A datasheet, So as AIPROPI is 1500uA/A, Does it mean DRV8231A only can sense 2A motor current? 

    Regards,

    Amber

  • 0 in reply to Amber Si
    TI__Genius 9230 points

    Amber,

    No, it means we recommend a IPROPI peak current around 3mA and motor current around 2 A RMS. This is to prevent excessive motor current in the driver and to protect the MCU from high current/voltage inputs. RIPROPI is to be sized according to the expected load current in order to access the full range of controller ADC in the MCU. 

    The current can be sensed at any range (low-side ONLY, not during Coast decay mode) but if it run consistently at higher than recommended, the driver can sustain damage or will disable outputs due to OCP or OTP. 

    Best,

    David