The TPS25946xx is an eFuse with integrated power path that is used to ensure safe power delivery in a system. The device starts its operation by monitoring the IN bus. When the input supply voltage (V_IN) exceeds the undervoltage protection threshold (V_UVP), the device samples the EN/UVLO pin. A high level (> V_UVLO) on this pin enables the internal power path (BFET + HFET) to start conducting and allow current to flow in both directions. When the IN supply voltage is insufficient (< V_UVP) or the EN/UVLO is held low (< V_UVLO), the internal power path is turned off, thereby blocking current flow in both directions.

After a successful start-up sequence, the device now actively monitors its IN voltage and load current from IN to OUT, and controls the internal HFET to ensure that the user adjustable overcurrent limit threshold (I_LIM) is not exceeded and overvoltage spikes are cut off after they cross the user adjustable overvoltage lockout threshold (V_OVLO). The device also provides fast protection against severe overcurrent during short-circuit events on OUT pin. This feature keeps the system safe from harmful levels of voltage and current. At the same time, a user adjustable overcurrent blanking timer allows the system to pass moderate transient peaks in the load current profile without tripping the eFuse. This ensures a robust protection solution against real faults which is also immune to transients, thereby ensuring maximum system uptime.

The device also has a built-in thermal sensor based shutdown mechanism to protect itself in case the device temperature (T_J) exceeds the recommended operating conditions.