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DLPA2005: DLPA2005 keeps resetting the DLPC150 when connected to DLP2010NIR

Rishi Ranjan
Prodigy 10 points
Part Number: DLPA2005
Other Parts Discussed in Thread: DLP2010NIR, DLPC150
We referred to NIRscanNano design and software files for creating our own board including DLCP150, DLPA2005, DLP2010NIR for NIR spectroscopy application.
DLPA2005 keeps resetting the DLPC150(RESETZ low). Then DLPC150 keep resetting DMD by sending DMD_DEN_ARTZ low. I attached scope images.
Power On sequence is correct; Vofs,Vrst and Vbias reach specified values on their time. Fault shutdown occurs as all three Vofs, Vrst and Vbias falls to zero. Again it is starting the power on sequence and again resets; cycle repeats. What I observed in waveforms is first Vofs reaches its specified 10V as it should be. when Vbias and Vrst reaches its specified values at same time, suddenly Vofs falls below 10V and after few milli seconds reset occurs.
we have used the LBR2012T100K(10uH, 468mOhms, 150mA) instead of CBL2012T100M(10uH, 370mA, 1.3Ohm) as per reference design due to its unavailability reasons. Is this causing the problem? there was no such strange issue before few days on the same board; that time I was working on I2C to display test patterns. This strange problem has been coming for last few days. Can you suggest some solution.
  • 0
    TI__Intellectual 2655 points

    Hello Rishi,

    Could you please share the schematics ad list of changes other than the usage of LBR2012T100K. We shall review it and get back to you.

    Regards,

    Akhil

  • 0 in reply to Akhil Guntumadugu
    Prodigy 10 points

    Hi Akhil,

    Thank you for the reply. changes are as follows:

    1.Other than the Inductor, we used a schottky diode STPS140A instead of STPS0540A.
    2.we are not planning to connect photodiode with SENSE1, SENSE2 pins and GPIO11 and GPIO13 unconnected with DLPC150 as compared with NIRSCANNANO reference design.
    If you need any other details let me know. Schematic is shown below
  • 0 in reply to Rishi Ranjan
    TI__Mastermind 20980 points

    Hello Rishi,

    Thank you for uploading schematics.  Our team members will review it and get back to you in couple of days.

    regards,

    Vivek

  • 0
    TI__Intellectual 800 points

    Rishi,

    This is a common symptom of a damaged DMD. If Vofs droops too low the DLPA will drive its INTZ output low. This initiates a fault shutdown of the system. Once the shutdown is complete if PROJ_ON is high they DLPA will start up. If Vofs again droops too low INTZ is driven low. etc.

    Usually this is caused by a damaged DMD that draws more current than the DLPA can supply. Have you tried replacing the DMD?

    -Kevin

  • 0 in reply to Kevin Lowderman
    Prodigy 10 points

    Hi Kevin,

    Thanks for your reply.

    Currently, I only have single DMD. I already ordered few DMD, it will take some to time to get delivered to me. Also,  Now with the existing DMD I see some flicker every time RESETz is applied by DLPA2005. And when P1V8 (VCC) and all other signals are connected with DMD except Vofs,VBias and Vrst, open circuit voltages of Vofs,VBias, Vrst are reaching the specified value. Only when three voltages are connected with the DMD, fault shutdown occurs. This is extra information, I wanted to give. Also, Can you tell the possible reason of DMD damage after checking the schematics.

    Regards,

    Rishi

  • 0 in reply to Rishi Ranjan
    TI__Genius 10985 points

    Hello Rishi,

    Please expect a response from our team by mid next week.

    Regards,

    Austin

  • 0 in reply to Rishi Ranjan
    TI__Intellectual 800 points

    DMD damage of this type is typically due to hot plugging/unplugging.