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DRV8908-Q1: power dissipation question

Sherry Liang
Genius 10255 points
Part Number: DRV8908-Q1

Dear team,

When considering the power dissipation of Rdson, why we need to consider two currents, Irms and Ipeak? In my understanding, we only need to consider the Ipeak if we want to calculate the max power dissipation, because these two current won't existed at the same time. 

Thanks & Best Regards,

Sherry

  • +1
    TI__Guru 55605 points

    Sherry,

    The equation is just an example.  If motors are operating continuously (fully rotating with no STALL), then use only Irms for the calculation.  If motors are in a stall condition at any point in the operation, then I agree, only use Ipeak in the calculations for worst case.  

    Some applications never hit a stall...motors just rotate with no end stop.  That is where Irms should be used.  

    Regards,

    Ryan