Hi,
I am currently experiencing an issue with the bq24610 with the ACDRV connection point. In summary, I built 10 boards and all the charger worked flawlessly, and now that I built another 50, the circuit is not behaving anymore. The root cause of my issue is the following:
Vin = 24V, VFB = 21V, no battery connected just an external adapter
1- When connecting the ACFETs to the ACDRV pin at the 1k resistor I am getting a high frequency oscillation at around 22V which does not fully turn ON the input FETS and a high pitch noise is obtained.
When I remove the 1K resistor and just probe the board at the ACDRV pin, no oscillation is obtained and the voltage is at 19V.
Making the connection, the oscillation begins see below: GREEN = GOOD Board, YELLOW = Bad Board
Another side affect to this oscillation is that the ACDRV does not drive the MOSFET to fully OPEN where the gate voltage sits at 22V instead of the ACCDRV = VCC - 6V, and the voltage to the ACN and ACP pins is 2V below VIN.
I have tried placed a 0.1uF caps to slow down Q2 turn on, which inherently slowed down the oscillation but did not fix the ACDRV not driving the FETS fully open.
I am really confused as to why this is happening because if I force the ACFET open by tying their gates to GND, I am able to properly charge the batteries. Another challenging aspect to this issue is that if I lower the voltage to 21V, then the oscillation issue no longer appears.
I have experienced this issue with a battery connected or without a battery.
I would like to obtain more information about this pin ACDRV, as currently I do not have an answer on how to get ACDRV to behave properly.
May I please obtain a response soon as this issue is holding up a product I would like to release.
Regards,
Yohan
