In order to protect the device from over current and prevent excessive battery discharge current, the BQ25155 detects if the current on the battery FET exceeds I_{BAT_OCP}. If the short circuit limit is reached for the deglitch time (t_{DGL_OCP}), the battery discharge FET is turned off and start operating in hiccup mode, re-enabling the BATFET t_{REC_SC} (250 ms) after being turned off by the over-current condition. If the over-current condition is triggered upon retry for 3 to 7 consecutive times, the BATFET will then remain off until the part is reset or until Vin is connected and valid. If the over-current condition and hiccup operation occurs while in supplement mode where VIN is already present, VIN must be toggled in order for BATFET to be enabled and start another detection cycle.

This process protects the internal FET from over current. During this event PMID will likely droop and cause the system to shut down. It is recommended that the host read the Faults Register after waking up to determine the cause of the event.

In the case where the battery is suddenly shorted while charging and VBAT drops below V_SHORT, a fast comparator quickly reduces the charge current to I_PRECHARGE preventing fast charge current to be momentarily injected to the battery while shorted.