• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 151 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TPS54A24: PSPICE Average Model required

TPS54A24: Review the schematic

prabhjot kaur
Prodigy 140 points
Part Number: TPS54A24

Hello Sir/Mam

We are using part TPS54A24RTWR to generate multiple voltages in our Design , But as we don't have it's average model we cannot run frequency response to check stability of system.

So, Please review the schematics once , compensations and input output capacitors.

Vin= 5V

Vout=0.92V

Iout=8.2A

Ac Ripple=10mV pk-pk

Dc Ripple= 2%

Vin= 12V

Vout=3.7V

Iout=9.6A

Ac Ripple=4 %

Dc Ripple= 4%

Vin= 12V

Vout=1.5V

Iout=7A

Ac Ripple=2 %

Dc Ripple= 1%

  • 0
    TI__Mastermind 23740 points

    Hi Prabhjot,

    Thank you for your question. I am reviewing the schematics. Can you provide the ESR for the 470uF cap? And the voltage ratings of the output caps? Ideally, if you just share the part numbers that would work since I can check the DC-bias derating and compensation with that information.

    Thanks,

    Amod

  • 0 in reply to Amod Vaze
    Prodigy 140 points

    Hello Amod

    Thank you for your Response

    Your Requested Details mentioned below

    470uF = EEF-GX0D471R

    100uF=GRM21BC80G107ME15L

    22uF=GRT31CC71E226ME13K

    10uF= GRM188Z71A106KA73D

    0.1uF= 04025C104KAT2A

    If you need any other information please let me know

  • 0 in reply to prabhjot kaur
    TI__Mastermind 23740 points

    Hi Prabhjot,

    I did not see the 220uF details. I assumed it is a low ESR cap too.

    I would recommend changing the compensation network as follows to get around 50kHz crossover frequency which will help with better transient response.

    Rcomp and Ccomp below are references to the RC in series connected to COMP pin. Ccomp2 is the HF cap from COMP pin to ground.

    0.92V design:
    Rcomp: 15k
    Ccomp: 4.7nF
    Ccomp2: 100pF

    3.7V
    Rcomp: 30.1k
    Ccomp: 3.9nF
    Ccomp2: 33pF

    1.5V
    Rcomp: 22.1k
    Ccomp: 2.7nF
    Ccomp2: 68pF

    Everything else looks good to me. Hope this helps.

    Thank you,

    Amod

  • 0 in reply to Amod Vaze
    Prodigy 140 points

    Hello Amod

    Thank you for your Response

    Can you tell how you have calculated these compensation values and How it is affecting transient response for betterment.

    Regards

    Prabhjot

  • 0 in reply to prabhjot kaur
    TI__Expert 5045 points

    Hi Prabhjot,

    Amod is currently out for today, he will respond to this by tomorrow.

    Thanks,

    Calan

  • 0 in reply to prabhjot kaur
    TI__Mastermind 23740 points

    Hi Prabhjot,

    I am using the datasheet equations. And verifying the design loop response with WEBENCH. Initially, the crossover frequency was too low 10kHz or lower so that would probably have a more slow response compared to faster response now due to higher crossover frequency.

    Thanks,

    Amod

  • 0 in reply to Amod Vaze
    Prodigy 140 points

    Hello Amod

    Thank you for your support , We will implement changes.

    Regards

    Prabhjot