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TIDA-00951: The auxiliary 12V port (J6) cannot achieve the expected voltage

Part Number: TIDA-00951

Hello, I have just made a TIDA-00951 board in few days and try to do some experiment now. However, before I started my experiment, I found that the J6 (aux_LV_12V) did not work in a expected condition.

I set my DC power supply to 12V, turn off and connected to the J6 connector. Then I turn on the power supply, but the voltage shows on the digital screen of my DC power supply was only 4.2V (The power supply is not broken I promise). And I feel the position near the T4 transformer became hot.  I have checked several components nearby but didn't find the problem. I thought there should be somewhere short in the circuit and the 4.2V was the voltage of D4.(a 5.1V Zener diode) 

So, I'd like to ask if you may have some suggestion to deal with this kind of issue. Or what may cause the issue in your experience and opinion. 

By the way, when I turn on the 12V power supply (connect to J6), all the other connector are not connected, including the TIDA-01281 port. I was trying to use a F28379D DSP to replace it (I thought that should be ok), but I didn't connected it to the J5 connector when I test the Aux_LV_12V port.

  • Hi,

    There maybe some mistakes in your circuits. Please check the following method:

    Test the resistance of Clamp_Vcc to clamp_source, it should be more than 1kohm;

    2, check the polarity of D12 and D13, do not reverse;

    3,check the transoform T14, its dot terminal must be correct (1-2-5-6), do not reverse.

    At last, thanks for your question, but you should have some basic knowledge of circuits debuging.

  • Thanks for the reply, I have to admit my lack of circuit debuging knowledge.

    I'v tested it again, the polarity of transfromer and diodes is correct. The resistance of Clamp_Vcc to Clamp_Source was shown as OL on the  multimeter (so there is no doubt that the resistance is more than 1kohm).

    After that, I use another board which has no T4 transformer on that (I removed the transfromer). Under this condition, the J6 shows expected voltage values(12V). But I found that the voltage value of LV_Aux_5V point was not 5V but more than 10V.

    I'm not sure if the U11 was broken? Meanwhile the U12 became quite hot in a short time. Should I also replace another one?

    Also, I'm not sure whether the LV_AUX_5V is provided by U11 (buck from 12V) or TIDA-01281?

    Or maybe there are some other issues I'v not noticed. Any suggestion will help me a lot.

  • Hi,

    I think there are some mistake in your circuits. Suggest you to check them by unit circuits, one by one.

    for example, power 'LV_AUX_3.3V' with 3.3V, to see if the 3.3V is normal and the after circuits works well;

    then power 'LV_AUX_5V' to see 3.3V is good.

    so as other power branches,