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BQ76930: BQ76930- TIDA-01093

Jack Deng
Expert 1090 points
Part Number: BQ76930
Other Parts Discussed in Thread: TIDA-01093

Hi TI guys

I'm using BQ76930*2 in my 20S packs project，I designed it follow the TIDA-01093.

but there are two questions that need your help, thx.

1,what's the function of Q31?

2,what's the function of Q33?

thx

  • 0
    TI__Guru 54715 points
    Hi Jack,
    I did not design the circuit, however:
    Q31 allows the charge FET gate to drop below GND_B potential. Without it Q30 would be a voltage follower and the charge FETs would turn on again if the battery voltage was much less than the charger voltage.
    Q33 provides a voltage drop to allow variation of the voltage at the Q32 source without triggering the expedite shutdown circuit (Q34, Q37) mentioned in the TIDA-01093 design guide section 2.1.