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TPS65263-1Q1: IC Pd equation

kura
Genius 4840 points
Part Number: TPS65263-1Q1

Please let us know TPS65263-1Q1 IC Pd equation ?

  • 0
    TI__Expert 3480 points

    PD = VIN × IIN × (1 – Efficiency) –  IOUT2 × DCR

    PS: Next time when you write a question. pls write clearly what's Pd because it may confuse readers.  Thanks.

  • 0 in reply to Gavin Wang (Zejing)
    Genius 4840 points
    Gavin -san
    Thank you for your reply.

    Total Pd = Inductor power dissipation(L1,L2,L3) + Output capacitor power dissipation(CO1,CO2,CO3) + Input capacitor power dissipation(Cin1,Cin2,Cin3) + IC Pd + IC iq Pd(IDDQ_NSW)

    Is above my understanding correct ?

    We woud like to know IC Pd equation that include SW frequency,Rdson_HS*,Rdson_LS*.
  • 0 in reply to kura
    TI__Genius 15135 points

    Hi, Kura

    The total Pd is including HS_FET and LS_FET switching loss, HS_FET and LS_FET conduction loss, inductor DCR loss, output/input capacitor ESR loss, IC Iq Pd(NSW), IC internal driver PD, and Qrr loss.

    HS_FET and LS_FET switching loss and conduction loss are dominated, usually, we just calculate switching loss and conduction loss to evaluate the effeciency.

    HS_FET switching loss: Vin*Fsw*Io*Tt. (Tt is transition time of SW voltage, SW from low to high time(Tr) or SW from high to low time(Tf), assume Tt=Tr=Tf.)

    LS_FET switching loss: 2*Vd*Io*Td*Fsw. (Td is dead time, Vd is body diode forward voltage.)

    HS_FET conduction loss: Io^2*Rdson_HS*D. (D is duty.)  

    LS_FET conduction loss: Io^2*Rdson_LS*(1-D).

    The other loss calculation is very complicated, so suggest to pease refer DCDC books and papers.