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BQ78PL114: PowerPumpTM Active Cell Balancing Technology

Vilen Bagdasarov
Prodigy 70 points
Part Number: BQ78PL114
Other Parts Discussed in Thread: BQ34110, BQ34Z100-G1, BQ76PL455A, BQ76PL536A, EMB1499Q, EMB1428Q


Hello dear friends. I want make BMS with Power Pump Balancing technology. Batteries, basically on wich will be placed BMS, consists from 50 pcs Lifepo4  3.65v   90A (182v 90A) or  4v 90A (200V 90A). For my solution i want use bq78PL114S12 and bq78PL102. Can i use these IC chip (not outdated yet  status NRRD)? What do you recommend use in my solution?

  • 0
    TI__Guru 73830 points
    The Pl114 and PL116 devices do not support LIFePO4 cells very well. They also only support up to 16S pack configurations. You could use the bq34z100-G1 gauge or the bq34110 gauge and voltage scaling to support a 200V pack. I will let the AFE group recommend the best cell monitor / protector to support this application.
  • 0 in reply to ThomasCosby
    TI__Guru 54715 points
    Hi Vilen,
    There is not a current monitor which supports power pump balancing. The bq76PL455A is a stackable monitor for cell voltages. It supports passve balancing. If active balancing is desired see the 16-Channel Active Cell Balance Reference Design (www.ti.com/tool/TIDA-00817 ). The MCU can read the cell voltages and control balancing. The monitor does not provide current measurement and protection or switching control. Current can be read from the gauge, add circuitry for fast current response and switching if needed.
    The bq76PL536A is also stackable voltage monitor with passive balancing.
  • 0 in reply to ThomasCosby
    Prodigy 70 points

    Thank you for information, next time i will attentively read documentation.

  • 0 in reply to WM5295
    Prodigy 70 points
    Hello , I will think about TIDA-00817 (TIDA shematic hard for me), if you have any idea for active balancing please say me about it. Thank you for support.
  • 0 in reply to Vilen Bagdasarov
    Prodigy 70 points

    Also, please recommend to me IC for charge lifepo4 in 200v-400v range.Thank you.

  • 0 in reply to WM5295
    Prodigy 70 points

    Thank you,  good variant BQ76PL536A ,i find schematic BQ76PL536A with active balancing , but in datasheet nope information about support active balancing. 

  • 0 in reply to Vilen Bagdasarov
    TI__Guru 54715 points
    Hi Vilen,
    The bq76PL536A supports passive balancing directly. It could be used to measure cell voltages to support an active balancing system, but does not directly control active balancing. It could be used for the cell measurement in place of the bq76PL455A in the TIDA-00817, but it would take more parts. A block diagram indicating active balancing may be a misunderstanding.

    I'm not aware of high voltage charging devices, the charger forum may provide more information.
  • 0 in reply to WM5295
    Prodigy 70 points

    Thank you I got it.  Do you know, I saw in bq76PL455A  datasheet  it was written  supported Passive Balancing with External n-FETs and Active Balancing with EMB1428Q/EMB1499Q it is right? Can I use in my application bq76PL455A for 50 pcs and more cells? I understood,  what monitor does not provide current measurement and protection or switching control. For that i can use power supply with charging control IC with CC&CV algorithm.What you think about it? It will work with lifepo4? Have a good day.

  • 0 in reply to Vilen Bagdasarov
    TI__Guru 54715 points
    Hi Vilen,
    Right, the circuit using the bq76PL455A with active balancing using EMB1428Q and EMB1499Q is demonstrated on TIDA-00817.
    Since your appliction has 50 cells and the bq76PL455A supports 16, you would need 4 parts with less than the full cell count, perhaps 2 parts or modules with 12 cells each and 2 with 13 cells. The reduced cell count may allow you to reduce the number of the multiplexers from the TIDA-00817 example. The part should work well with LiFePO4 cells, be sure to split the unused inputs across the multiple monitors so that the minimum voltage is met. It would not work to have the cell split across the modules such as 16, 16, 16, 2.
    Correct, the monitor does not include current measurement or protection in either direction, be sure to limit or protect appropriately for your design.
    Also note that the devices are controlled by a MCU, TIDM-TMS570BMS provides a reference design.
  • 0 in reply to WM5295
    Prodigy 70 points

    The number of cells can be 48 and 64 (50 pcs bad example). The cost of the system becomes more expensive with using the bq76PL455A .Cheaper bq76PL536A with passive method. I will think to make the final decision.Thank you for support.