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.

TPS61178: some questions of TPS611781 and request of review schematics

Part Number: TPS61178

Hi.

My customer is using to TPS611781RNWR.

he designed the circuit by referring to webench.

However, some issues were discovered during testing.

Input : 3V-4.2V

output : 5.7V at 5A

when Ccomp is 1nF at no load,  output current was increased up to 400mA. and Inductor humming noise occurs.

I have some questions

1. I would like to know the detailed use of the Ccomp pin.

2. when this device using, how to decrease inductor humming noise.

3. Is there a way to use the TPS611781 product without connecting an external clock to the FREQ/SYNC pin?

Finally,

please review the schematic.

thanks,

regards,

robin.

  • Hi Robin:

    May you share the waveform of Vin, Vout, SW and better with current of the inductance? 

    For your questions:

    1. I would like to know the detailed use of the Ccomp pin.

    [MQ] It's hard to say in short words, you can check the loop compensation in datasheet. 

    2. when this device using, how to decrease inductor humming noise.

    [MQ] I want to check the root cause about it. It could be caused by loop stable, or some protection function like UVLO

    3. Is there a way to use the TPS611781 product without connecting an external clock to the FREQ/SYNC pin?

    [MQ] It's OK to connect it with an proper resistance. Details are in the datasheet. 

  • Hi Robin:

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

  • Hi 

    Thanks for reply.

    I asked him for the waveform.

    plz wait to reply.

    thanks,

    regards,

    robin