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TPS65150: Flash issue

Jesse Lee
Expert 1985 points
Part Number: TPS65150

hello

We use TPS65150 for 14' display panel.

When it powered up, there is a flash of white light. (refer to file 0617_1.mov, and the shematic refer to tps65150.pdf)

how to deal with it?

In the datasheet, page 28,  

8.2.2.10 Power-On Sequencing
Rearranging Equation 12 and inserting td1 = td2 = 1 ms and Vref2 = 1.213 V,

In Equation 12,  why set the td1= 2.5ms, but not 1ms?

what is the suitable value for td1 and td2?

what is the range of C11 and C12?

Thanks a lot1

2055.TPS65150.pdf

  • 0
    TI__Expert 6330 points

    Hi, 

    I have notified our expert regarding this topic. Please expect a response by 6/21/19.

    Thanks,

    Aaron

  • 0
    TI__Mastermind 18550 points

    Hello Jesse,

    Let me answer some of your questions in-line as below:

    >>When it powered up, there is a flash of white light. (refer to file 0617_1.mov, and the shematic refer to tps65150.pdf)

    >>how to deal with it?

    It could be that TPS65150 AVDD/VGH/VGL rails are coming up momentarily and than the device is shutting down. Can you capture some scope shots of AVDD/VGH/VGL rails as system is powering up to see the status of these supplies? With Cfdly of 100nF in your schematics,  if any one of these supplies does not achieve regulation within the ~45ms, the device will shutdown. If that is the case, focus needs to be why the supply is not able to achieve regulation within this time.

    Also, it appears that Vin is 5V in your application and in that case C30 in schematics should be 2.2nF and R1 should 0 ohm. Please see table 1 in datasheet.

    >>In Equation 12,  why set the td1= 2.5ms, but not 1ms?

    I am not sure what you mean by this. equation 12 is not setting td1=2.5ms. In application schematics in the data sheet as well as in your own schematics, with Cdly1 and Cdly2 each at 10nf, tdly1 and tdly2 will be ~1ms.

    >>what is the suitable value for td1 and td2?

    1ms can be a reasonable value as it is in your schematics.  

    >>what is the range of C11 and C12?

    There is no specific range but values in 1nf to 100nf should be fine.

    Kind Regards,

    Liaqat