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Reverse charger protection

Genius 3300 points
Other Parts Discussed in Thread: BQ40Z50

1. I have to give reverse charger protection for battery management system in which N-channel mosfets are in ground path.

2. Attached is the ckt for bq40z50 in which N-channel are on +ve path i.e Q2 & Q3.
Battery is coonected across Bat+ & bat- & charger is connected across Pack+ & pack-.
In this circuit Q4 is for reverse charger connection protection. Suppose charger is connected in opposite direction then there is +ve voltage at gate of Q4 & ground at its source. It turns on the Q4 & it then it shorts gate & source of Q3, so protecting any current to flow.

3. Now i have a circuit in which n-channel are on ground path, I have to add reverse charger polarity in it also. Current Circuit without protection is attached with name actual

4. I had modified it as in attached file modified for reverse charger protection.

5. Can't use series diode since it drops at voltage & for 1S configuration this drop is high. Ideal diode are expensive.


Query:
1. Is the modified circuit is ok?
Bat volatage in 1S configuration is 2.5V to 4.5V & charger voltage is +4.5V max
Bat volatage in 2S configuration is 5V to 9V & charger voltage is +9V max

2. Can it be done with one single mosfet. as in bq ckt.