• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 695 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.

Original question:

BQ25713: BQ25713 + BQ34110 with NiMH: overkill?

BQ34110: Using BQ34110 + BQ25713 for NiMH

Elder Costa17
Expert 2825 points
Part Number: BQ34110
Other Parts Discussed in Thread: BQ25713, , GPCCEDV

This is a follow-up question of a previous one I posted.

I am using BQ25713 as the charger. BQ34110 would detect charging termination and do fuel gauging as I also need to have an estimation of the charge left when the equipment is operating on battery.  My concern is BQ34110 is very sophisticated and, from documentation, it looks fairly complex to use, communication wise. Thus, I would like to know if  BQ34110 is the way to go in my application or if there is a simpler approach I may be missing.

If the former (i.e. BQ34110 is the way to go), I would like to know if calibration is mandatory. I do not need absolute accuracy of the time left so I would like to avoid calibration in production if I could. What would I miss if I used a fixed configuration tuned to the battery pack?

Thanks  in advance.

  • 0
    TI__Prodigy 590 points
    Hello Elder,

    For the calibration, it is recommended to calibrate each board to achieve current/voltage measurement accuracy. And you could choose to calibrate several boards ( 10~20) to get the average calibration data of you PCB board integrated in the golden file.

    Generally Ti gauge using similar development flow.
    1. battery profile test to get the coefficient. For bq34110, it is an CEDV gauge, based on the coulombs counting and compensated end of discharging voltage to calculation the Stat of charge. To start on it, you could refer the online GPCCEDV tool to get the parameters.
    2. configure the gauge. import the data getting from GPC tool, and then change some parameters like design capacity, number of cells
    3. running charging/discharging cycle to get the production file, we called golden file.

    Hope this helpful for you to start the development.
  • 0 in reply to Jessica LI
    Expert 2825 points

    Hello, Jessica,

    Thank you for your comments.

    What about the complexity side of the question? My original concern, asked in a different topic, was about the combination above (i.e. BQ25713 + BQ34110) being overkill. I just want to make sure I am not following an unnecessarily complicated path.

    Thank you.

    Elder.

  • 0 in reply to Elder Costa17
    TI__Guru* 81035 points

    Hi Elder,

    Yes, both devices are needed since the charging and gauging function are different ICs. Gas gauging does have some complexity, and the BQ34110 has many settings because it can work with multiple battery chemistries. To make the setup easier, I created a spreadsheet to help that I am attaching. For this spreadsheet, you can enter some basic information like number of cells, cell chemistry, and the basic battery specs and it will give you suggested values for most parameters. 

    Calibration is important and it is also important to go through the CEDV data collection for your battery for accuracy. However, there is an EDV_CMP bit that can be set for fixed EDV values if you are not concerned about accuracy over load and temperature. To learn about this option, I recommend reading pages 7-9 of this document: http://www.ti.com/lit/pdf/slua924. It is written for a different gauge, but the information still applies for the BQ34110.

    /cfs-file/__key/communityserver-discussions-components-files/196/0830.bq34110_5F00_dataflash_5F00_notes_5F00_rev03_5F00_20181002.xlsx

    Best regards,

    Matt

  • 0 in reply to Matt Sunna
    Expert 2825 points
    Hello, Matt.

    Thank you very much for the spreadsheet and information on calibration. I will dig into the documents and come back should any further question arise. I just wish days had more than 24h. :)

    Best Regards.

    Elder.