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BQ77PL900: I don't want the battery to cut itself off.

shin jiwoong
Prodigy 20 points
Part Number: BQ77PL900
Other Parts Discussed in Thread: BQ76925, BQ76930

I'm developing a battery that's used for drones.
I don't want the battery to cut itself off. 
I want to quit my main pcb by judging it from the main pcb after receiving only status information from BQ 77 90000. 
This is the only way to stop the battery from turning off the output and dropping the drones. 
I'm developing in HOST MODE, is that possible?

  • 0
    TI__Guru 54715 points

    Hi Shin,

    The only maskable protection in the bq77PL900  is the undervoltage in host mode.  See the UVFET_DIS bit.  OV and current protections are always active.  The host can choose when to check temperature but when checked its protection is always active.  You may want to move FET control to a separate driver controlled by the MCU.  

    Depending on your cell count, the bq76925 provides AFE monitoring features for up to 6 cells. It does not have internal protection or FET drive but has a current comparator for fast alert to the MCU.  The bq76930 is a monitor device for 6 to 10 cells, it has voltage and current protections which can not be masked from the low side FET signals, but the low side signaling may be easier to interface to logic than the high side outputs of the bq77PL900.  You may also be interested in the application report Fault Monitoring for High-Availability Systems using the bq769x0.