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LM53600-Q1: IC Power Dissipation

Brian Wang0928
Genius 14330 points
Part Number: LM53600-Q1


We'd like to know how to calculate the IC's power dissipation correctly. In the WEBENCH result, there is a IC Pd shown. how to calculate it? Could you offer formula of the power dissipation including bias power, FET switching, fixed power losses and others...etc! Very thanks.

 

  • 0
    TI__Genius 10720 points

    Hello Brian,

    I've attached an article that is very in depth in terms of the various losses.

    https://www.ti.com/lit/ml/sluu271/sluu271.pdf

    The simplest way to get a good approximation of buck IC power dissipation would be the following:

    • efficiency (%) = (Pout/Pin)
    • Pout is determined by your Vout Iout requirements and efficiency can be found in the device datasheet for a given operating condition
    • Solve for Pin
    • Pout - Pin = IC dissipated power + inductor power dissipation + input capacitor power dissipation + output capacitor dissipation + feedback resistor power + conduction losses through the traces + other
      • The losses here are dominated by the IC dissipated power and inductor power dissipation. Inductor power = (Iout)^2 * DCR gives a reasonable approximation
      • After solving for this you can solve for IC dissipated power

      The method I've outlined is rather simplified but can still offer a good approximation of IC power dissipation, if a more accurate model is needed, then the article is your best bet.

      Regards,

      Harrison Overturf