Urgent__TPS61088 trouble shooting help needed

Discussion in 'The Projects Forum' started by mishra87, Aug 16, 2016.

  1. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    Hi all,

    I have got the attached EVM . That is designed for 5V@10A.

    So my load requirement is 5V@10A and li ion 3.7 v as a power source.

    Please have a look of attached schematic datasheet of "TPS61088EVM-667" for refereence.

    In jumper JP3, I want to enable and dissable E pin of IC.

    If I short E pin to ON , i get 5V output but if I short E pin to OFF I do not get 0V output and what do i get outputs voltage is irrespective of battery voltage lets say 3.2V input and hence 2.9V output.

    Now my questions are...
    1. Why do not I get completely OFF means when E pin shorted to OFF . There should 0V but I am getting 2.9V as I already explained.

    2. I do not get logic signal at output means when E shorted to ON I get 5V . When it is shorted to OFF I do not get the stable output i.e. 2.9V. It comes with time delay of let's say 30mS. Why this time delay.

    3. I want to completely shut down the IC after a specific period of time means there is no output voltage appears and dc - dc converter drain very less current.

    4. How it can be implemented to completely shut down the load in case of output voltage is 2.9V.

    5. Is there any alternate solutions are available.

    Please answer accordingly on the basis of point so that it's easy to understand for me.

    Thanks in advance...!!!
     
  2. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    Still comment awaited. ...!!!
     
  3. ScottWang

    Moderator

    Aug 23, 2012
    4,850
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  4. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    Nobody on the way to help me out...!!!
     
  5. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    I hardly see any proper guidance in my post. People are not interested in my technical things and doubt. !!!

    I have tested above module.
    I am not getting completely OFF output while E pin connected to ground. Output follow input with .3-.4V difference.

    When E pin connected to VCC the ouput is designed for 5V.

    I want to also let you know that There is 30ms delay in output between the transition of E=1 to E=0.

    E=1, OUT=5V
    E=0, OUT= Vbat-.3V let's say if Vbat=4V then out=3.7V.

    1. Can we completely OFF the out put.
    2. Can we completely OFF the Out out when E=0.

    Could anybody guide me...!!
     
  6. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    5,671
    899
    Can't answer all of the questions, but the decay in output when EN is grounded is explained here in the datasheet:
    upload_2016-8-17_16-10-1.png

    When you measure an output voltage while in shutdown, what load do you have on the output? Try putting a 10 k resistor as load and measure the voltage.

    John
     
    mishra87 likes this.
  7. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    All the data given above is no load measurement and we have testing for 5V @10A. Is that any possibilities that in no load the IC does not go completely in shutdown mode and we are getting some output voltage.

    Let me check with at least resistive load and get back to this forum. ..!!!
     
  8. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    I
    I am not much expert on interperating the datasheet what I can understand from above is ..

    When EN=1 , the full load output is let's say 5V and inductor charge fully.

    When EN=0, the output voltage and inductor currents falls towards zero and not completed zero.

    Isn't that possibility of inductor not getting discharge path and hence it follows input in shutdown mode.

    Thanks
     
  9. Brevor

    Active Member

    Apr 9, 2011
    279
    54
    Because you don't listen to us...
    DID YOU PUT A LOAD ON THE OUTPUT ???
    ANSWER THE QUESTION !
     
    mishra87 likes this.
  10. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    • I had holiday yesterday, let me check today and get back to you all.
    • With resistive load .!!!
     
  11. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    As per my understand this chip has not got load disconnect function so it will never go down to zero .

    Anyway today I will very with load.!!!
     
  12. mishra87

    Thread Starter Member

    Jan 17, 2016
    166
    2
    Hi,

    i have tested with 10K and 20E resistor respectiviley .
    But i din see any fall in voltage , its same as described above .
    EN=1, 5V
    EN=0, Vin-Vf

    So it does not work.
    Lets think about other options..!!!
     
    Last edited: Aug 19, 2016
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