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DRV8876: IPROPI Voltage

Anjanaa N
Intellectual 400 points
Part Number: DRV8876


Hi,

I am using DRV8876 in my design, with the VPROPI reference set with 2.5V. 

I have tried to measure the IPROPI ADC reading to get IPROPI . While calculating IPROPI with the ADC voltage got a current value which differs from the multi-meter reading in current mode. 

I am using, VIPROPI (V) = IPROPI (A) x RIPROPI (Ω) this formula to get IPROPI current value.  I am getting IPROPI in mA.

What will be the unit of IPROPI current? 

For example, ITRIP = 1.5A; with the formula getting 1.3mA is this correct?

Kindly clarify that the formula I am using is right and IPROPI reading using multimeter is recommended?

Regards,

Anjanaa

  • 0
    TI__Mastermind 37683 points

    Hi Anjanaa,

    Thank you for posting to the motor drives forum.

    Your equation to calculate the IPROPI current is not quite correct. You forgot to include the current mirror scaling factor which is 1000 (uA/A). The correct equation to calculate the current is as follows:

    Where LS1 and LS2 is the current flowing from the drain to source of the low side FETs. In your case, you measured 1.3mA but you forgot to multiply by the scaling factor (1000). So your actual current should be 1.3A which is closer to the actual Itrip value of 1.5A.