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  • TI Thinks Resolved

TLV61048: Problem under 45mA load (on 13V)

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Replies: 24

Views: 133

Part Number: TLV61048

Dear

Schematic in attachment, when we have 30-45mA load the voltage drops to +-12,4/12,5V. How to fix this?

Greetings

Thomas Van Aken

  • Dear,

    It is now an avg of 13V (added 1uF from cathode to gnd) but our display is still flickering. Will measure ripple voltage tommorow and update this case.

    Looks to be unstable.

    Greetings

    Thomas Van Aken

  • In reply to Thomas Van Aken:

    Hi Thomas:

    Where did you measure the Vout? 

    I wonder the converter enters into power save mode with such load. Please catch the waveform at Vin, Vout, SW to check it.

    Best Regards

    Minqiu

  • In reply to Minqiu Xie:

    Hi Thomas:

    As long time no hear from you, I assume you have solved the issue. If not, just reply below. Thank you!

    Best Regards

    Minqiu

  • In reply to Minqiu Xie:

    Dear

    It is super busy here, will try to send you this tonight.

  • In reply to Minqiu Xie:

    Dear

    Vin gets dirty from the chip. But see Vin, Vout, Vsw!

    VOUT:

    VSW:

    Vin:


    Greetings

    Thomas Van Aken

  • In reply to Thomas Van Aken:

    Hi Thomas:

    May you use a resistance for loading to help debug? I'm not sure if it's caused by load transient.

    According to the waveform of Vin and Vsw, it seems the Vin drops obviously. May you check the valley value of Vin? The UVLO of TLV61048 is 2.4V. 

     

    Best Regards

    Minqiu

  • In reply to Minqiu Xie:

    Vin drops to 2.4V (but this is caused by the boost conv.), will now do a cont. load test instead of the oled.

  • In reply to Minqiu Xie:

    Dear,

    Problem stays with cont. load of 20mA. See attachment! (other scope since we have alot of other set-ups).

  • In reply to Minqiu Xie:

    Dear

    Any idea what happens? Since we need to fix this asap ...

  • In reply to Thomas Van Aken:

    Hi Thomas:

    Sorry, it seems the reply is missing.

    What's your power supply? I wonder why it drops so much? Do you have current probe to catch the current waveform of inductance?

    Additionally, please also remove the load to check if it can startup without load. 

    Best Regards

    Minqiu

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