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Strange HW Error on EVM: TMDSACDCKIT(C2000 AC/DC Developer's Kit)?

violet han
Intellectual 325 points

Hi

I'm a new user of EVM: TMDSACDCKIT(C2000 AC/DC Developer's Kit). I was following the FBPS guide to run demo program provided. I used "BUILD 1" option(open loop FBPS). But I found some very strange thing.

 

If I apply 12V at J9, the 12V, 3.3V, 5V, 3.3V isolated are all ok. DSC can output PWM. I can monitor/change phase shift for practice.  But if I add 15V at J26, J27, there is no PWM output. 12V, 3.3V, 5V, 3.3V isolated are all ok, too.  On scope i can find the DSC stops output pwm signal just after 1-2 pwm signals.  However, it sinks the same current as in normal operation condition(i.e 12V_aux-power added condition).  I tried to test all points. And I found if I add 12V at U14 output, both TP73 or TP75 can make DSC output PWM normally. But if I move the input voltage at the beginning end, i.e, J26, J27. It doesn't work.

I think this is quite strange. Could anyone help me on this? Thanks in advance.

By the way, I asked where to add the aux-power before. Brett helped me. He suggested me use 5V. However, it seems this board has some options. For my board, the U17 is DCR011203U, so I have to use 12V as aux-power. Can anyone let me know why we have some small deviations on one EVM?

 

Thanks,

Violet

  • 0
    TI__Genius 10820 points

    Violet,

    When you connect the 15V input at J26-J27, is the 12V aux. supply also connected at J9? The 12V supply should be connected as well. I believe Brett meant that you should use a 12V aux supply for the driver circuit to be powered. Please use a 12V supply at J9.

    Hrishi

     

  • 0 in reply to Hrishi Nene
    Intellectual 325 points

    Hrishi,

    Thanks for your reply. But according to schematic, a 15V at J26-J27 is good enough to provide both for power stage and for aux-power for driver circuit. But the strange thing is , if I use aux-12V at J9, there is PWM output. If I use 15V  at J26-J27, there is no PWM output although it has same paths as aux-12V.

    Violet