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TPS65130: Sometime no Negative output on TI TPS65130RGER

Hao Zhen
Prodigy 20 points
Part Number: TPS65130

Hello,

I am currently designing a PCB board using the Texas Instrument TPS65130RGER DCDC converter and facing some issues with this component. I hope you can help me to solve my issues.

I am having two issues with this part:

  1. Sometimes this chip only can generate +15V output but no -15V output when I power up the board. I have to power cycle the board several times to get both power output working.
  2. Every time I power up this chip, the L81 and L80 inductors in the following picture start whining. Is there a way to get rid of or minimize the noise?

My design followed the datasheet typical application design.

Thank you,

Hao

  • 0
    TI__Expert 6330 points

    Hi Hao,

    I have notified our expert regarding this topic. Please expect a response by 6/22/20.

    Thanks,

    Aaron

  • 0
    TI__Mastermind 18550 points

    Hello Hao,

    I did not see a picture or schematics in your post. Can you please attach schematics of you design? I will review your schematics to see if I can spot what may be causing the issue that you are seeing.

    Kind Regards,

    Liaqat

  • 0 in reply to Liaqat Khan
    Prodigy 20 points

    Hi Liaqat,

    Thanks for your help! Here is the schematic. 

    Best,

    Hao

  • 0 in reply to Hao Zhen
    TI__Mastermind 18550 points

    Hi Hao,

    Thanks for sending the schematics. I reviewed it and recommend to add a 51.1K ohm resistor in series with C399 on the -15V_NR side of the this capacitor. We have seen that in some noisy designs, there is too much  noise coupling into FBN pin through the feed forward capacitor C399 and that can destabilize the operation of inverting converter. Adding this resistor in series will reduce the bandwidth of the feed forward path and reduce this noise coupling.

    Also, based on the feedback resistor values, I calculated the values of feed forward capacitors C398 and C399 to be 6.6pF and 5.7pF respectively. I would suggest to use standard value that are close to these values instead of the 56pF that is used in the schematics currently.

    Kind Regards,

    Liaqat