The BQ25185 includes a SYS voltage regulation loop. By regulating the SYS voltage the device prevents downstream devices connected to SYS from being exposed to voltages as high as VIN_OVP. SYS regulation is only active when V_IN > V_UVLO, V_IN > V_BAT + V_SLEEP and V_IN < VIN_OVP .

For the BQ25185, if the ILIM/VSET is configured for a VBATREG setting higher than 4.3 V, the device regulates the SYS voltage in battery tracking mode. As battery voltage increases, VSYS is regulated to 225 mV above the battery. If the battery is less than 3.6 V, the VSYS will be regulated to V_MINSYS. This regulation occurs to ensure proper termination of the battery even if VDDPM is active.