SLUSDK0A August 2020 – March 2021 BQ25171-Q1
The device indicates the charging state on the open-drain STAT1, STAT2 pin. This pin can drive an LED.
|CHARGING STATE||STAT1 PIN STATE||STAT2 PIN STATE|
|Charge completed, charger in sleep mode or charge disabled (including VOUT > VRECHG after TMR_EXP for NiMH charging)||HIGH||HIGH|
|Normal charge in progress (including intermittent charge active for NiMH, and automatic recharge for Li+ charger)||HIGH||LOW|
|Recoverable fault (VIN OVP, BAT OVP, TS HOT, TS COLD, TSHUT)||LOW||HIGH|
|Non-recoverable or latch-off fault (VSET/CHM_TMR/ISET pin short/open, BAT OCP, TMR_EXP for Li+ charging, VOUT < VRECHG after TMR_EXP for NiMH charging)||LOW||LOW|
Safety timer expiration event (TMR_EXP) is addressed differently depending on whether the charger is configured as a NiMH or Li+ charger. For Lithium-based charging, TMR_EXP is reported as a non-recoverable fault by setting STAT1 = LOW and STAT2 = LOW. For NiMH-based charging, TMR_EXP with VOUT > VRECHG is the expected termination method, and shall be reported as charge complete with STAT1 = HIGH and STAT2 = HIGH. For NiMH-based charging, TMR_EXP with VOUT < VRECHG is a non-recoverable fault and shall be reported by setting STAT1 = LOW and STAT2 = LOW. An input supply or CE pin toggle is required to attempt charging after a non-recoverable fault is detected.