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LED driver outputs - possible damage pathway?

Mehdi Mir31
Prodigy 10 points
Other Parts Discussed in Thread: BQ20Z80

I am interested to know whether the LED drivers pins on the BQ20Z80 are active buffer/totem pole or open drain/collector IO.

We seem to have a potential situation where an external LED drive circuit for an off board LED may be damaging the BQ chip and then going on to damage the AFE.

The LED output pin of the BQ is connected to the gate of an NMOS thru a 300ohm resistor. The gate is pulled high by a 499K resistor to BAT+ (3S ~ 12V) and has a .1uF cap to GND/BAT-

We have seen the 3.3V regulators fail. The LED being stuck ON or not coming on. We have seen AFE damage and leakage.

Can this circuit be the source of all this. Could the .1uF cap be acting like a 12V source to discharge into the 3.3V circuitry?