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VIN MON PROBLEM IN UCD9244 WITH UCD7242

Sakthi Annamalai
Intellectual 610 points
Other Parts Discussed in Thread: UCD9244, UCD7242

Hi,

        We are using UCD9244 with UCD7242 for 1.2V,2.5V,1.8V & 3.3V in  our board design.  We made prototype and then programmed the PWM through Fusion design. The PWM controller with Power driver worked fine for months time.  Suddenly we are facing issue with the output voltage .. Sometimes,the PWM controller is generating voltage for a minute time and getting shut down  . Sometimes ,the controller enters  into Shutdown mode directly after powering on the boardThe voltage at the Vin Mon is less than 500mV always. But as per design it should be in the range of  2V to 3V for proper operation. We have checked the voltage divider circuit  and everything fine.

Please let me know what could be the problem.  

Regards,

Sakthi.A

  • 0
    TI__Genius 9845 points
    Hi Sakthi,Additional information may help us analyze the problem:
    1. Do all of the UCD9244 have the same problem, or only one particular device has the problem?
    2. What is the fault shown in the Fusion GUI?
    3. You mentioned “Vin Mon is less than 500mV”. Is it read from GUI, or directly measured?
    4. Is the actual Vin voltage correct and stable?Thanks!Zhiyuan
  • 0 in reply to Zhiyuan Hu
    Intellectual 610 points
    Hi Hu,

    1. No only one UCD9244 creating the problem. This UCD9244 interfaced with two power drivers UCD7242 which generates 1.2V,2.5V,3.3V & 1.8V.

    2. Yet to verify the fault through Fusion GUI

    3. Vin mon measured directly at the junction

    4.The actual Vin voltage 12V is stable
  • 0 in reply to Sakthi Annamalai
    TI__Genius 9845 points

    Hi Sakthi,

    1. GUI is our primary source to analyze a problem, as it reads states and faults from inside the device. 

    2. If Vout is correct, the resistor divider output is below what it should be, I suspect hardware problem: (1) bad soldering on the resistor divider; (2) the UCD9244 monitor pin is damaged and sinks current.

    You mentioned the circuit was working fine in the past, but not working now. Did any event happened in between?  But again, I would like first see the GUI faults. 

    Thanks,

    Zhiyuan