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DLPC3479: DLPC3479 DMD Voltage, DMD_VOFFSET, DMD_VBIAS, DMD_VREST Output issue

LP Kim
Intellectual 480 points
Part Number: DLPC3479

Tool/software:

Dear TI Members

After improving the auto initialization failure, we checked the DMD power supplies and found an issue where the DMD power drops after the auto initialization is completed.

Although the voltage drop of the 19V input was compensated, the first attempt was successful, but the same issue continues to occur afterward.

Please review the issue 

Thanks 

Best Regards 

  • 0
    TI__Intellectual 1180 points

    Hello,

    Thank you for reaching out and using the E2E forums! An expert from our team will review the thread and get back to you shortly.

    Regards, 
    Tristan Bottone

  • 0 in reply to Tristan Bottone
    TI__Genius 9945 points

    Hello LP,

    From where are you probing the power? The 19V is the supply side of a step-down converter. This seems to drop down to ~8V at the lowest. I'd like to see how stable the +12V supply is.

    For my clarity, between the first and second image there was no actual change between hardware connections, this was just retest after power cycling the system, correct?

    Best,

    Aaron

  • 0 in reply to Aaron Black
    Intellectual 480 points

    Dear Aaron Black 

    For my clarity, between the first and second image there was no actual change between hardware connections, this was just retest after power cycling the system, correct?

    [LP] No chagen hardwware connection. I operated  PROJ_ON Toggle signal.

    [250122-Q1] I would like to know if it is possible to control the system operation through software adjustments.

    After a normal auto-initialization, can we verify that the HOST/SLAVE IRQ is low, check the DMD power, and then enable it again?

    Thanks 

  • 0 in reply to LP Kim
    Intellectual 480 points

    Dear Aaron Black 

    [From Data sheet] 

    Interruption of the supply voltage occurs when, for example, the adapter is switched to another mains outlet. Achange of supply voltage from, for example, 20 V to 8 V can occur, and thus the OVP level (which is ratio metric, see Section 7.3.2.5.2) could become lower than VLED. An OVP fault will be triggered and the system switches
    off.

    [Test #1] 

    I believe that VIN is affected by VLED. The default LED Current in the TI FW Selector is set to 10A. After modifying the default to 5A and downloading the updated Beam FW to our hardware, the issue was resolved.  Test ismage was dispalyed 

    [Test #2 -will do] 

    The improvement measure for Test #1 is planned to be used temporarily. We will finalize it by adjusting the capacitor value connected to VLED or VIN.

  • 0 in reply to LP Kim
    TI__Genius 9945 points

    Hey LP,

    I'm glad you were able to resolve your issue! Thanks for pointing out the datasheet explanation, this will help others in the future as well!

    Please reach out in the future if necessary!

    Best,

    Aaron