• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 2 answers
  • Subscribers 63 subscribers
  • Views 172 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:

BQ2970: Choosing the right battery protection circuit variant

BQ2970: How much higher than the battery limits are the protection thresholds typically chosen?

Jorge De La Rocha
Prodigy 150 points
Part Number: BQ2970

If a single cell LiPo battery has a 1C charge rate of 400mA and a 2C discharge rate, how much higher should the BQ2970 protection parameters be set to? What is acceptable practice?

For reference, here is the link to the battery in question:  https://www.batteryspace.com/polymer-li-ion-cell-3-7v-400-mah-pl-402248-2c-----un38-3-passed-ndgr.aspx

Thank you,

Jorge

  • 0
    TI__Mastermind 42060 points

    Hello Jorge,

    I would recommend you read Section 10.2.1-10.2.2 of the datasheet. Your protection values are dependent by different factors of your circuit design. At a quick glance, the BQ29737 part might work fine based on your battery specs and the design steps. But I would recommend you follow the design steps yourself and find what works best for you.

    Best Regards,

    Luis Hernandez Salomon

  • 0 in reply to Luis H. S.
    Prodigy 150 points

    Hello Luis,

    I did look at those sections but my question is related to how much higher, above the battery specs, is the customary rule of thumb to set the protection thresholds.

    Thank you,

    Jorge 

  • 0 in reply to Jorge De La Rocha
    TI__Mastermind 42060 points

    Hello Jorge,

    This would depend on the tolerances of your charger/cells. From the datasheet of your battery, you want to charge up-to 4.2-V and discharge to 2.75-V. You should choose protection values to values you know you won't want to trigger under normal discharge/charge (taking into account your system's tolerances to avoid false trigger). There isn't any rule of thumb for what you want to choose

    In the end this is up to you to calculate and choose.

    Best Regards,

    Luis Hernandez Salomon