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TPS53647: TPS53647 ripple problem at full load

Feng bin Su
Expert 7590 points
Part Number: TPS53647

Hi team,

As title, my customer has faced the  high ripple problem at full load. It is about  100mV ripple.

It is very similar with the question below.

Is it the stability problem? Would you have any suggestion about it?  Please refer the schematic as below.

https://e2e.ti.com/support/power-management/f/196/t/877324?tisearch=e2e-sitesearch&keymatch=tps53647%20ripple

  • 0
    TI__Expert 5830 points

    Hi Ben,

    How's the ripple at light load? Can you please probe the switching node as well? How's the way customer measuring the ripple? They should use pig tail or differential probe, which one did they use? You can try to use TI GUI to change RAMP from 150mV to 200mV to see if it helps.

    Thanks

  • 0 in reply to Chasel Chen
    TI__Expert 3775 points

    hi Chasel,

    Customer tries to adjust ramp level to get better ripple.

    ramp level: 150

    light load ripple: 60mV, 

    ramp level: 200

    light load ripple: 76mV, 

    ramp level: 40

    light load ripple: 22mV,  heavy load ripple: 32mV

    few questions:

    - should I adjust ramp level to reduce the ripple?

    -another concern and how to make sure it's ok like jitter performance?

    -how can i use USB to GPIO tool to read the current information on the GUI? how to fill the address and length?

    BR,

    frank

  • 0 in reply to Frank(EP) Liu
    TI__Expert 3775 points

    hi Chasel,

    any comment for last questions.

    BR,

    frank

  • 0 in reply to Frank(EP) Liu
    TI__Expert 5830 points

    Hi Frank,

    - should I adjust ramp level to reduce the ripple?

    You can change the ramp to 200mV to reduce the ripple, usually to increase the ramp will make the ripple lower, but from your result it is opposite...

    -another concern and how to make sure it's ok like jitter performance?

    How's the jitter waveform looking like?

    -how can i use USB to GPIO tool to read the current information on the GUI? how to fill the address and length?

    You can refer to the PMBus spec in the datasheet or use the TI GUI, you need to use the PMBus command.

    Thanks

    Chasel