TI中文支持网Part Number:BQ76952
在BQ76952应用中，Q4能否省去，省去的话会给电路带来什么问题吗？
Star Xu：
您好，不建议将Q4去掉。
DSG does not go below VSS, so without the clamp circuit of Q4 the gate of Q3 would remain near 0V and Q3 would operate in a source follower mode while a reverse charger was attached. With Q4 on Vgs of Q3 is about 0, Q3 remains off and PACK+ falls to a negative voltage. This creates a large voltage across R39 and R41 which are sized to dissipate the power required in that condition. Since R39 and R41 are a large value to keep the power dissipation manageable, turn off would be slow, so D10 and R40 operate in parallel for DSG turn off to turn off the Q3 in a suitable time.
See the application note https://www.ti.com/lit/pdf/sluaa09 section 2 for test result and additional description.
