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bq77910

Mohit Chopra
Intellectual 830 points
Other Parts Discussed in Thread: BQ78PL116, BQ77910A

7848.bq77910.rarI am doing a project on higher amperes Li-ion cells battery pack. So I prepared a schematic of bq77910 with multiple N channel Mosfets. I am having some doubt regarding increasing the mosfets only be sufficient or there is some need of mosfet driving circuitry like in bq78pl116. I here by attaching the schematic which I prepared & please give me some points whether it needs rectification or the design is ok.

Regards,

Mohit Chopra

  • 0
    TI__Guru 54715 points

    The schematic looks much like the EVM schematic and may have features you don't need. Another community member was approaching a high current design but did not post results.  You might find the general comments at that post helpful http://e2e.ti.com/support/power_management/battery_management/f/180/t/209614.aspx. As it is drawn your board should be versatile, but if you can narrow its application you may be able to reduce a number of parts or patterns.

    The parallel FETs may switch OK without extra drive. Note the bq77910A test conditions for the CHG and DSG outputs are with 50 nF load. The driver like the bq78PL116 would not be directly applicable since it is for high side P channel power FETs, but it could be easily adapted if you want the high side P channel.  If you need more drive for the gate you would likely need a FET gate driver or buffer for the DSG and possibly CHG.

    If you are doing a split charge and discharge path, check to see if you need all the charge FETs if the charge current is lower than discharge.  Also check connection of the Q6 & Q7 sources to an external terminal.

    On sheet 2, be sure to populate appropriate components for your selected cell count.  See the datasheet for the recommended connection of unused cells.