• State
  • Locked Locked
  • Replies 6 replies
  • Subscribers 63 subscribers
  • Views 879 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ20Z95: Using BQEVSW software I would like to be able to troubleshoot if I have the correct resistor values for R12/R13 and R33/34/40/41 as on the Datasheet Application schematic

Bob Kilpatrick
Prodigy 40 points

Part Number: BQ20Z95

Using BQEVSW I would like to be able to troubleshoot if I have the correct resistor values for R12/R13 and R33/34/40/41 as on the Datasheet Application schematic. The circuit card we are testing uses the Schematic application provided in the Datasheet for BQ20Z95DBT.  We are a production facility that are building these boards now and our parts for the 100 ohm resistor mentioned before have no part markings to verify value. Needless to say we put 1K Ohm resistors in there and our customer kicked the boards back to us. So we have noticed that 1k ohm resistors seem to indicate a negative value for current and average current values using the BQEVSW software on the SBS tab.  Is there another way to verify the wrong values using this software?  In the dataFlash or Pro portions?  This negative indication seems to indicate wrong resistor 90% of the time for R12 and R13 on the current sense portion of the circuit but that is not good enough for a production environment. Is there a way to verify the R33/34/40/41 on the SMBD/C portion of the circuit using the BQEVSW software?

  • 0
    TI__Guru* 76230 points
    Hi Bob,
    I do not believe the resistor values to be the issue. You must have swapped traces going into the GSRN and GSRP pins and also possibly the ASRN and ASRP pins. So check and compare the reference schematic and yours to see how the traces should go

    thanks
    ONyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 40 points

    Traces are good.  When we have 100 ohms  in we get zero or positive in the  Current and current avg.  This  board is hooked to a test fixture so we cannot assume  there is  no connections but it is the same connections for a good board as well as a bad one.

    When we have an incorrect value in (1K) we will get  sometimes a continuous negative and other times a brief negative going to 0 but never a positive.

  • 0 in reply to Bob Kilpatrick
    TI__Guru* 76230 points
    Ok, short of measuring the resistor values, there is no way to use the gauge to determine the values of those resistors. You will have to ensure then that the correct resistor values are being populated on your board.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 40 points

    One More try!   If there is current flowing through the sense resistor it means there will be a voltage drop.  The reading at GSRN and GSRP will be different if a 100 ohm resistor is used  when compared to a 1000 ohm resistor. Assuming that is correct can I detect that? Can I use Pro and peek and poke to see what the value is? Is there a process or method to see that? My calculations indicate that if there is a 1 V drop (which is max) across ASRN and ASRP there would be a voltage at GSRN and GSRP of 1.999E-6 for 100 ohms and a voltage of 0.2 E-6 for 1000 ohms. Is this detectable?

  • 0 in reply to Bob Kilpatrick
    Prodigy 40 points
    When I go into Pro I notice if I read 0a that I get positive numbers (>0004) for good 100 ohm boards and FFF4-0000 for bad 1K ohm resistor boards. Is this possible?
  • 0 in reply to Bob Kilpatrick
    TI__Guru* 76230 points
    the gauge cannot detect or measure the values of those resistors