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TPS63002 not working

Sidhyesh Ramugade62853
Prodigy 130 points
Other Parts Discussed in Thread: TPS63002, TPS63000, TPS63001

We are testing TPS63002 for generating 5V/0.4A output. The input for the circuit is single cell lithium ion battery (3.7V/850mAH). As the input is connected, the output is 0V for both load and without load condition. We checked the enable pin & found it to be high. Also there is no switching taking place on either of the inductors ( L1 / L2 ). We also wired TPS63002 on the evaluation board TPS3000EVM-148. The output was same as mentioned above. Can you suggest cause for the same and how to proceed for obtaining the desired output?

Thanks

Sidhyesh

  • 0
    TI__Guru**** 150650 points

    When using the fixed versions of the IC on the EVM, you must replace R1 with a 0 Ohm resistor.  You can remove R2 if you want.  This connects the FB pin directly to Vout.

    Can you try testing with a lab power supply instead of the battery?  Have you measured Vin on the board?

    If neither of the above help you, you may have damaged the IC either through ESD or through the heat required to install it on the EVM.  Can you try out another IC?

    What kind of board were you trying it on originally?

  • 0
    TI__Mastermind 36110 points

    Because the TPS63000 family is so integrated and easy to use, there are very few thingst that could be wrong with the design.  You need to confirm that each pin on the IC has the expected voltage.  You also need to confirm that the GND and PGND pins are electrically connected on the PWB.  Another thing to confirm is that the IC is properly oriented (placed) on the PWB.  You may have it soldered down so that it is rotated 180 degrees from where it should be.  The TPS63000 EVMs are tested before being shipped, so the fact that both of your boards are not working points to a test setup problem.  I'm looking forward to hearding back from  you on what the resolution to this problem is.  If you are unable to solve it, I'm looking forward to seeing more test info so I can provide additional guidance.

  • 0 in reply to Chris Glaser
    Prodigy 130 points

    Dear Chris,

                          We are aware of the fact that TPS63000 is used for variable output, TPS63001 is for fixed +3.3V output & TPS63002 for +5V fixed output. While wiring TPS63002 on the EVM, we replaced R1 a 0 Ohm resistor and removed the resistor R2.

    We also carried out the test with a power supply and measured the input voltage Vin.

    As far as the original boards are concerned, we wired 8 of our own boards with TPS63000. They are working fine with and without load. We had designed those boards for 3.3V/0.2A output. We had modified some of these boards for +5V using both TPS63000 (with R1 and R2 as per +5V output) and TPS63002. The results were the same.


  • 0 in reply to Sidhyesh Ramugade62853
    TI__Guru**** 150650 points

    Sidhyesh Ramugade said:

    We had modified some of these boards for +5V using both TPS63000 (with R1 and R2 as per +5V output) and TPS63002. The results were the same.


    By 'the results were the same', so you mean that this setup also worked or also didn't work?  Did modifying the TPS63000 with the external resistors to produce 5V work or not?  If so, then the most likely explanation for the TPS63002 not working is that it was damaged during assembly onto the PCB.  Another possibility is that not all the IC's pins are making good contact with the pads, so that some are open circuited.  Try reflowing the IC onto the board again and if that doesn't work replacing the IC altogether.

     

  • 0 in reply to Chris Glaser
    Prodigy 130 points

    Dear Chris,

                             By 'the results were the same', i mean that the output was zero with either of the setups. We modified the TPS63000 with external resistors to produce +5V. But there was no output.

    And as far as the damaging the TPS63002 while assembly on the PCB or the possibility that the IC's pins not making contact with the pads(i.e. they are open circuited), we had used the same mechanism / technique to assemble the IC on the board from which we got 8 Boards working with TPS63000 for producing +3.3V. There negligible room for fault / flaw in the assembly.

    Can you suggest remedy for the problem?

     

    Thanking You

    Sidhyesh

  • 0 in reply to Matthew Day
    Prodigy 130 points

    Dear Michael,

                               The GND and PGND are electrically connected on the PCB.The IC is also oriented properly on the board. And by ' test setup problem ', what exactly you want to convey? Can you elaborate on that?

    Can you suggest remedy for the problem?

    Thanking You

    Regards,

    Sidhyesh

  • 0 in reply to Sidhyesh Ramugade62853
    TI__Guru**** 150650 points

    Ok, so the 8 circuits on your own board work while nothing works on the EVM board?  Is that correct?

    Did the EVM work before you modified it?  Have you made any changes to the EVM, other than to the resistors and IC?  i.e. replaced the inductor or caps, etc.

    If you have measured Vin on the EVM and it is in the proper range, and if everything on the board is connected as it should be, and yet you still get no output, I can only conclude the IC itself is broken.  To confirm this, you can take the IC off of the EVM and install it your own board and it should also output 0V.

    Did you acquire the ICs that work on your board from the same vendor and/or lot as the ICs that do not work on the EVM?

  • 0 in reply to Chris Glaser
    Prodigy 130 points

    Dear Chris,

     

    Yes the boards are working. As far as the EVM is concerned, now with TPS63002 it is not working.

     

    EVM did work before the modifications.We had replaced the inductor with 3.3uH one and capacitors with 10MFD/6.3V (X5R dielectric) one on input and two on the output.

     

    We will test the to check whether the IC is broken or not.

    We got these IC's as sample from TI.

     

    Thanking You

    Regards,

    Sidhyesh

  • 0 in reply to Chris Glaser
    Prodigy 130 points

     

    Dear Chris,

                       Two of our PCB’s are wired with TPS63002 for obtaining output of 5V/0.4A.There are no other components on the PCB. Under no load condition, following is the output:

    Board 2: For input of 3 - 4.2V, the output was 5V. But the input current was 10 – 5.3 mA.   

    Board 3: For input of 3 - 4.2V, the output was 5V. But the input current was >10 mA.

     

    We replaced the input / output capacitors with the ones on EVM. But the result was same.

    As per the datasheet the input current should be less than 50uA.

    Can you suggest the cause for the same?

     

    Regards,

    Sidhyesh

  • 0 in reply to Sidhyesh Ramugade62853
    TI__Guru**** 150650 points

    I'm glad you were able to get the IC to output 5V.  Hopefully, Sanjay can help you get the circuit to work as you wish.  Please continue to keep him in the loop as he is more familiar with your needs and is physically closer to you.

    It sounds like you are operating the TPS63002 in forced PWM mode (PS/SYNC = High).  Tie this pin low for battery powered applications to get the lowest input current.

    Also note that the Iq spec of <50uA that you mentioned is not input current.  Iq is measured when the device is not switching--it is the current required to run the IC minus the current required by the power stage or gate drivers.  The no load input current will always be greater than the Iq.  The no load input current is a customer specific parameter that depends on the external components used and the operating conditions.  We can only specify what the IC consumes to run, which is the Iq.