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WEBENCH® Tools/TPS54160A: TPS54160A

Juzer Tarwala
Prodigy 120 points
Part Number: TPS54160A
Other Parts Discussed in Thread: TPS54160

Tool/software: WEBENCH® Design Tools

Hi team,

I Have some issue regard frequency component calculation.

Vin=12V,       Vout=3.3V,       Iout=1.5A,       Cout=47uF with Resr=10mohms (ceramic capacitor),       gmea=97uA/V

As according to the tps54160a datasheet i have calculated the value of modulated pole and zero and  got the crossover frequency range from 7.696Khz to 45.3534Khz.(using datasheet equation no. 43,46)

Selecting crossover frequency = 40.24Khz  I further calculated following values:(using datasheet equation no.47,48,49,50)

Gmod=0.542,       Rc=78.46Kohms (76.8Kohms),       Cc=1371pF (1500pF),       Cf=5.98pF (6.8pF)

Now when i stimulate by placing the component with same value as above in webench stimulation software selecting tps54160A ic, the software shows the crossover frequency = 29.81Khz instead of 40.24Khz.

Am i calculating it correctly or am i making some mistake.

Please help me out the above query. Thank you

  • 0
    TI__Intellectual 1710 points

    Hi Juzer,

    The webench has cout selected to be 47uF*2 (please look at quantity) and the derated value is 52uF. you can find the ESR by clicking select alternate parts. it is around 1.9 mOhms. Please use these correct values and recalculate the compensation.

    Please let us know if you face further issues.

     

  • 0 in reply to Vishwanath Tigadi
    Prodigy 120 points

    Hi Vishwanath Tigadi,

    Thanks for your replay.

    I have noticed that  at the output we have 2 capacitor and have changed it to 1 capacitor of value 47uF and 10mohms by adding custom component.

    The result i have return above have the circuit given below.

  • 0
    Prodigy 120 points

    Hey,

    On reading the datasheet carefully I came across this point that says they have ignored the effect of the slope compensation that was internal to tps54160.

    And therefore the calculated crossover frequency is greater than the webench stimulation crossover frequency.

    Above point is written on page no. 34 of tps54160 datasheet.