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Original question:

TPS65150: Vin=5V, Vout=14V/20mA, -14V/XmA, -5V/20mA

TPS65150: While HALO on LCD at startup

abhishek Anant
Prodigy 10 points
Part Number: TPS65150

we have been using the IC TPS65150 for powering a LCD using in the product design we are into at the moment 

The main supply is from a DC-DC buck-boost 5V source 

The HALO effect is seen mostly during startup in some of the prototypes , but is random in nature.

Which eventually fades OFF and then everything is back to normal.

Is there a way if the IC is configured wrong?

  • 0
    TI__Expert 6330 points
    Hi,

    I have notified our expert regarding this topic. Please expect a response by 2/28/19.

    Thanks,
    Aaron
  • 0
    TI__Mastermind 18550 points
    Hello,

    I reviewed your schematics and noticed couple of items:
    1. CTRL pin should be directly connected to Vin. No need for the 10K ohm resistor.
    2. Your design is using a doubler for positive charge pump and and your set voltage for VGH is also close to double ~18V from a ~9.5V AVDD. I am thinking that there may not be enough margin for doubler to achieve set voltage for VGH. As an experiment, can you change your AVDD voltage to around 11V by changing the resistor divider ratio and see if this resolves the issue?
    If it does not resolve the issue, I would suggest to compare scope plots of AVDD, VGH, VGL and Vin on a good versus a bad board to notice how they come at startup and debug it from there.

    Kind Regards,
    Liaqat