Hi team,
Can BQ40Z50 exit sleep mode when a charger is inserted?
Btw, when gauge enters into sleep mode and CHG is turned off, if a high load is connected, the discharge current will flow through the body diode of CHG, how to avoid damaging the CHG FET?
Thanks!
Jayden Li
Hello Jayden,
I'm a bit confused by the question, are you seeing the gauge wake up from sleep when a charger is connected? And if so, does it happen when a charger stays connected without charging (below sleep current)? Here is the table of all of the conditions to enter/exit sleep:
As far as I am aware, connecting a charger should not wake the gauge up from sleep (but will wake it up from shutdown). If it is happening, can you check the sense resistor pins to see if a transient may be causing the issue? And if possible, sharing a log will make this easier to solve.
As for the second part, the gauge does have a countermeasure for this. When the gauge reads a current above the DSG current threshold, it will enter discharge mode and turn on the charge FET automatically. This is intended to protect the body diode in a situation like this. It isn't instant though, so I suppose there could still be an issue if the load is high enough for the short time. In the worst case it could take 1 second. Although, the hardware protections act much faster (us-ms scale) and could also help if they are set accordingly.
If you are worried about this occurring, you may be able to work around it by turning on sleepchg or ensuring the DSG FET is normally off until you know it is safe to turn on.
thanks,
Alex M.
