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BQ29200: How to use BQ29200 ?

Part Number: BQ29200
Other Parts Discussed in Thread: BQ2000

Hello Expert,
May I have some questions regarding to your BQ2920x balance charging protection IC ?

Here's the detail of my product.

- 2S2P 18650 lithium battery pack is used.
- Capacity of each battery cell is 3000mAh.
- Maximum voltage of each battery cell is 4.2V. For battery pack, it will be 8.4V.
- Charging current for each battery cell in CC mode is around 1500mA ( 0.5C ). For battery pack, it will be 3000mA.
- Peak discharge current from each battery cell is around 3000mA ( 1C ). For battery pack, it will be 6000mA.
- Your BQ2000 is used for battery charging. Power supply voltage for BQ2000 is 12V.

Q1) BQ2920x has 2 types such as 4.30V and 4.35V. Each type is suitable for my battery pack or it also has one in 4.20V ?

Q2) How to define the value of cell balancing current ? I guess it will not be just several tenth mA only.

Q3) If external cell balancing configuration will be used, which MOSFET is suitable ?

Thank you!

Best regards,

  • Hi Fai,

    1. We do not have a version of the BQ2920x that has an over voltage protection at 4.2V. If the battery states that it has a max voltage of 4.2V, exceeding that could be very dangerous and is not recommended. 
    2. The cell balancing current is defined by the Rcb values. See section 7.6 of the datasheet for more information.
    3. See section 9.3.1 of the datasheet for an example of cell balancing using external FETs. We do not have a certain part number that we recommend, so the decision can be made based on your application.