When a battery with voltage greater than V_BATUVLO is connected with no input source, the battery FET is turned on similar to supplement mode. In this mode, the current is not regulated; however, there is a short circuit current limit. If the short circuit limit is reached, the battery FET is turned off for the deglitch time (t_DGL(SC1)). After the recovery time (t_REC(SC1)), the battery FET is turned on to test and see if the short has been removed. If it has not, the FET turns off and the process repeats until the short is removed. This process is to protect the internal FET from over current. If an external FET is used for discharge, the external FET's body diode prevents the load on SYS from being disconnected from the battery. If the battery voltage is less than V_BATUVLO, the internal battery FET (Q4) remains off and BAT is high-impedance. This prevents further discharging of deeply-discharged batteries.