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DRV8876: DRV8876 Thermal

Ian Wang
Mastermind 29700 points
Part Number: DRV8876

Hi Sir,

My customer using DRV8876 test case temperature around 50 degree C in ambient temperature condition.

Do you think it looks a little bit higher?

Thanks, Ian.

  • 0
    TI__Mastermind 37683 points

    Hi Ian,

    It is possible to reach those temperatures If the board layout has not been optimized for good thermal dissipation. Poor thermal dissipation may cause the temperature to greatly increase. 

    Is the customer using their own board design or the DRV8876EVM? 

    Is the output current measurements RMS or peak values (constant values)? 

     

  • 0 in reply to Pablo Armet
    TI__Mastermind 29700 points

    Hi Sir,

    It’s in customer’s PCB measure RMS current.

    May I know how to calculate thermal according measure current value?

    Thanks, Ian.

  • 0 in reply to Ian Wang
    TI__Mastermind 37683 points

    Hi Ian,

    This application note explains how to calculate power dissipation. When calculating power dissipation, you have to consider the RDS(on) power dissipation and switching loss. In this case, the RDS(on) dissipation can be calculated as follows: 2*0.350*0.598^2=0.250W. The switching loss, assuming 20kHz frequency, is roughly equal to 0.0126W which is very small  compared to the RDS(on) power dissipation. So the largest contributor of power will be the from RDS(on) unless the customer is switching at a much higher frequency.