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DRV8718-Q1: how to set the unidirectional current sensing

Colt Zhang
Expert 5015 points
Part Number: DRV8718-Q1

hi Team, 

from the data sheet, i want to know how to set the current sensing to the unidirectional, because customer use low side PWM drive control.

just need set the Vbias=1/8 Varef?

customer use Varef=5V, from calculate, Vso-uni=(Varef-0.25)-(Varef/8)=(5-0.25)-(5/8)=4.125V, but from the customer test, the voltage is just 0.6V. 

so my question is : how to set unidirectional current sensing, when Varef=5V, and how to set the Av and Rshunt.

  • 0
    TI__Mastermind 23421 points

    Hey Colt,

    Yes, set CSA_DIV=1 for VAREF/8 should 

    Colt Zhang said:
    how to set the Av and Rshunt.

    RSHUNT is the value of the shunt resistor on the PCB.  Av (Amplifier gain) is the calculated value according to equation 16, which you should then use that value to set CSA_GAIN_1 (or 2) to be less than that calculation.  

    Regards,

    Jacob