• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 183 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

BQ79606A-Q1: Daisy Chain Communication Loss and Voltage Sampling

Stanley Dai
Expert 5810 points
Part Number: BQ79606A-Q1

Hi Team,

Here are two question from customer needing your help.

1. Battery voltage sampling question: Customer feedbacks that our BQ79606 will have voltage sampling error when opening balance function. For example, one cell sampling value is higher with corresponding one is smaller, but the added sample value is normal. Is that normal for our IC?

2. Customer feedbacks our daisy chain communication is unstable and sometimes is losing signal. This communication loss issue happens randomly. They want to know which factor may have large influence here. So they can have the debug direction. 

Many thanks for your help.

Best,

Stanley 

    

  • +1
    TI__Prodigy 50 points

    Hi Stanley,

                  Here are the responses to the customer’s two questions.

    1. When opening the balancing function, it is possible to see a difference in sampled voltages because of the intrinsic wire impedance. If you reference figure 18 in the BQ79606 datasheet, you can see that wire impedance is depicted as Z_cable and that VC and CB are connected to it. When cell balancing is turned on and current is drawn, the wire impedance results in a voltage drop between the cell and device. The voltage drop across the wire could cause deviations in the sampled voltages.
    2. In terms of debugging the issue with daisy chain communication, first make sure that the connections between devices are stable and good. If the problem continues, what faults are you receiving in the fault summary? Are you following our design recommendations? (link to design recommendations) Could you send us a snippet of your schematic?

    Best regards,

    Anthony