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TIDA-050045: Power dissipation detail

Priyadharshini E
Prodigy 60 points
Part Number: TIDA-050045

Hi Team,
Could you please help us to calculate the power dissipation for the below parts used in this reference design,
1.T2
2.Q10
3.Q11
4.Q6
5.Q8

  • 0
    TI__Intellectual 770 points

    Hello Priyadharshini, 

    For the power dissipation of the transformer (T2) , we will need to contact the transformer vendor for more information about the core loss.
    I will get back to you with a more definitive answer soon, along with the calculations for the FETs.

    Thanks,
    Sarah

  • 0 in reply to Sarah Lao
    Prodigy 60 points

    Hi Sarah,
    Thanks for the response
    Waiting for your answer

  • 0 in reply to Priyadharshini E
    TI__Intellectual 770 points

    Hi Priyadharshini,

    You would need to contact the transformer vendor to find their core loss. This particular design uses 750318938 from Wurth Electronik.

    FET power losses can be calculated with the following:

    You may approximate FET losses by summing the switching, conduction (and gate drive) losses.
    The FETs in this particular design do not have internal resistor, so you may neglect gate drive loss.

    P_dissipated = P_sw + P_cond

    P_sw = (E_on + E_off + E_rr) * f_sw
    Values for the switching energies (E_on, E_off, E_rr) may be found in each FET's respective datasheet, however I believe some do not include this value.
    In that case, you may estimate using:

    E_oss = 0m5*C_oss*V_ds(off)^2

    And then use 10*E_oss to approximate (E_on + E_off + E_rr)
    f_sw is the switching frequency, typically 250 kHz

    P_cond = I_rms^2 * R_ds(on)

    Best,
    Sarah