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  • TI Thinks Resolved

TPS61041: Load Regulation

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Replies: 9

Views: 543

Part Number: TPS61041

Hi,

We got a question from the customer about TPS61041.
Could you help us?

[Question]
Is there the data of load regulation by EVM? They measurared the load regulation by thier own board. Please refer to below figure. Is this result reasonable?

Rfbt=1.8M, Rfbb=200k -> Vout=12.33V

Best Regards,
tateo

  • Hi Tateo,

      I will test the load regulation by EVM and I will reply to your later.

    Best Regards,

    Jing Ji

    Step-up (boost) Switching Regulator Solutions

  • Hi Tateo,

      The EVM load regulation is as below picture.

    Best Regards,

    Jing Ji

    Step-up (boost) Switching Regulator Solutions

  • In reply to Jing Ji:

    Hi, Thank you for your support. And sorry to bother you again. Could you provide the waveform of Vout ripple by EVM? The condition is Iout=1mA.

    They measured the Vout ripple by their own board. Please refer to below figure. Is this result reasonable?

    Best Regards,
    tateo

  • In reply to tateo yamashiro:

    Hi Tateo,

     This output ripple is not reasonable. Could you test output cap and use short ground probe? I guess your test condition is wrong.

    Best Regards,

    Jing Ji

    Step-up (boost) Switching Regulator Solutions

  • In reply to Jing Ji:

    Hi, Thank you for your reply.

    They measured the output capacitor and used short ground trace. I checked their schematics and found the output capacitor is 1uF(16V). I think the effective capacitance is very low. Do you think this is related to the big output ripple? If you provide the waveform by EVM, it would be very helpful.

    Best Regards,
    tateo

  • In reply to Jing Ji:

    Hi, They added the output capacitors 1uF(50V)*2pcs and measured the waveform. There is still big ripple on the output voltage. They want to compare the waveform between EVM and their own board. Could you provide the waveform of output voltage ripple by EVM?

    Best Regards,
    tateo

  • In reply to tateo yamashiro:

    Hi Tateo,

      I just tested in the EVM. Vin=3.3V Vout=12.5V Iout=7mA

      Blue:output ripple Yellow: SW

      What kind of cap is your output cap? electrolytic cap? You could change to ceramic cap to have a try. 

    Best Regards,

    Jing Ji

    Step-up (boost) Switching Regulator Solutions

  • In reply to Jing Ji:

    Hi, Thank you for your support. How about the waveform at Iout=1m~3mA? Their waveform at 10mA seems close to your waveform. They assume this phenomenon is occurred at low output current(1m~3mA). They use GRM188B31H105KAAL (1uF,50V,1608) for output capacitors.

    Best Regards,
    tateo

  • In reply to tateo yamashiro:

    Hi Tateo,
    My test condition is Vin=3.3V Iout=3mA.
    Because E2E has some delay, we can talk about it by Email.
    I just sent your a message to tell you my email address.

    Best Regards,

    Jing Ji

    Step-up (boost) Switching Regulator Solutions

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