TPS54A24: Review the schematic

prabhjot kaur

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%

7 months ago

0 Amod Vaze 7 months ago

TI__Mastermind 23620 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 prabhjot kaur 7 months ago 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 Amod Vaze 7 months ago in reply to prabhjot kaur

TI__Mastermind 23620 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 prabhjot kaur 7 months ago 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 Calan Elaya 7 months ago in reply to prabhjot kaur

TI__Expert 4985 points

Hi Prabhjot,

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

Thanks,

Calan

0 Amod Vaze 7 months ago in reply to prabhjot kaur

TI__Mastermind 23620 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 prabhjot kaur 7 months ago in reply to Amod Vaze

Prodigy 140 points

Hello Amod

Thank you for your support , We will implement changes.

Regards

Prabhjot

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TPS54A24: Review the schematic