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BQ27742-G1 being used with LI Ion Polymer battery please help.

Other Parts Discussed in Thread: BQ27742-G1, GPCCHEM, BQSTUDIO

Hi All,

Hope somebody can help with this. We had a PCB developed that is using a BQ27742-G1 (partnered with BQ24170rgyt) and the battery  is a 3.7V 5000mAh  105080. We are trying to initialise this for use and have just found out that the engineer who designed this for us has no idea what he is doing. I have an ev2300 and can connect to the device on our board. What I need from what I have seen is an updated file that includes polymer battery to select from the chemistry tab.

Happy to answer any questions.

I certainly appreciate any help with this.

Chris

  • Hi Chris

    Your comment on the engineer not knowing what he is doing made me laugh out loud. Our gauges might appear fairly confusing but once you get the hang of it, it is really easy to use. 

    I have listed steps below on what needs to be done to create a golden file that will be programmed on multiple devices.

    The golden file creation process involves a few steps.

    -          Identify your chem id and program it on a chip (use an EVM). This process involves performing a relax-dischage-relax test and inputing the results in the gpcchem tool online. See the link. It contains instructions on how to run the test http://www.ti.com/tool/GPCCHEM?keyMatch=gpc%20chem&tisearch=Search-EN-Everything

    -          Perform V,I,T, cc and board offset calibration on that chip using bqstudio

    -          Carry out a learning cycle on that chip using your battery. Attached is an app note that describes how to carry out a learning cycle. At the end of learning cycle update status will change to 06. You should then manuallly Change cycle count to 0 and change update status to 02 indicating qmax has learned and resistance has been updated

    -          Then you extract either an srec, bqfs or dffs file. This will be your golden file which you will program on multiple devices in production. After programming on multiple devices, you need to enable IT (0x21) command before shipping.

    I hope this clarifies.

    let me know if you have questions on any of the steps

    7103.LearningCycleOverview_.pdf

    thanks

    Onyx

  • Hi Onyx,

    Thanks for the fast response. I will start to work through this. a couple of quick questions

    1. Do we actually need the evaluation board to be able to do this procedure or can we use our board and the EV2300?

    2. Is it normal for no charge/discharge when first turned on (no programming) i'm guessing this is a yes as this is what I am seeing. I guess this is to protect both the battery and the charging circuit.

    Again thanks for the response.

    Regards

    Chris

  • Hi Chris,
    You can do the test on your board. If the gauge is powered and woken from shutdown mode, the charge and discharge fets are immediately enabled to facilitate charge or discharge. if you are unable to charge or discharge, you need to check to make sure that no safety condition has been triggered and that your protector check sums are correct.

    thanks
    Onyx