• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 480 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.

EMB1499Q: Overcurrent failure, during cell discharging

user3473222
Intellectual 300 points
Part Number: EMB1499Q
Other Parts Discussed in Thread: EMB1428Q, EM1402EVM

Hello,

I am working on a custom active balancing board. Board uses EMB1499 + EMB1428 chipset. Balancing part is made according to the TI's Active Chipset Reference. The circuit is designed to work with 12s battery: there are two stacked  sets of EMB1499 + EMB1428. Energy is transfered between selected cell and the whole stack. I can discharge all cells normally (current set to 2.5 - 5.0 A). But when I try to charge cell 6th (top cell in the bottom half-stack), I receive "Secondary side limit" error. Schematics are attached below. Other cells can be charged and discharged successfully.

Regards

Vladislavas

7026.Stack.pdf6366.Bottom Switch Matrix.pdf1185.Bottom_Converter.pdf

  • 0
    TI__Genius 17370 points
    Hi Vladislavas,

    Thanks for the question, we are looking into this and will get back to you shortly. Have you seen on this error occur on multiple boards or just the one? And are you using our example code software or is this custom software?

    Thanks,

    Taylor
  • 0 in reply to Taylor Vogt
    Intellectual 300 points
    Hi Taylor,

    Thank you for your reply. I have seen this error on two different boards. And we are using our custom software. But I use the same procedure for all cells, and for both directions - charge and discharge. The only thing changed, is the cell number and the discharge/discharge bit in the command sent to EMB1428Q. And I see this error when charging the 6th cell only.

    On oscilloscope I saw, that disconnection of the charging stops just after the beginning of DC/DC conversion. I can see 9 switching cycles and then it stops. The "Secondary side current limit" is received on the next read - after 5 seconds when I send stop command (in normal operation charging should take 5 seconds).


    Vladislavas
  • 0 in reply to user3473222
    Intellectual 300 points
    Hi Taylor,

    It is a week since we posted this question and we are still encountering this problem. Is there any suggestion from your side?

    Vladislavas
  • 0 in reply to user3473222
    TI__Genius 17370 points
    Hi Vladislavas,

    Apologies for the delay. Nothing seems glaringly incorrect with the design, can you test a few things below? It is difficult to diagnose when there is custom hardware and software at play.

    1) Measure the secondary sense with DMM to check if this truly exceeds the EMB1499 datasheet specification.
    2) Test your hardware with our example code to check if you recieve the same error.
    3) Test your code with our EM1402EVM to check if the error is hardware related.

    Best Regards,

    Taylor