The TPS2491DGSG4 is a Retry Positive High Voltage Power-Limiting Hot Swap Controller that safely drive an external N-channel MOSFET switch. The power limit and current limit (both are adjustable and independent of each other) ensure that the external MOSFET operates inside a selected safe operating area (SOA) under the harshest operating conditions. Applications include inrush current limiting, electronic circuit breaker protection, controlled load turn-on, interfacing to down-stream DC-to-DC converters and power feed protection. The TPS2491 is supported by application notes, an evaluation module and a design tool. The falling OUT voltage is the result of M1 and CO currents through the short"s impedance at this time scale. The internal GATE clamp causes the GATE voltage to follow the output voltage down and subsequently limits the negative VDS to 1 to 2V.
The LT4356CS-2#PBF is a Surge Stopper protects loads from high voltage transients. It regulates the output during an overvoltage event, such as load dump in automobiles, by controlling the gate of an external N-channel MOSFET. The output is limited to a safe value thereby allowing the loads to continue functioning. The LT4356 also monitors the voltage drop between the VCC and SNS pins to protect against overcurrent faults. An internal amplifier limits the current sense voltage to 50mV. In either fault condition, a timer is started inversely proportional to MOSFET stress. If the timer expires, the FLT pin pulls low to warn of an impending power down. If the condition persists, the MOSFET is turned off. After a cool down period, the GATE pin pulls up turning on the MOSFET again. The auxiliary amplifier may be used as a voltage detection comparator or as a linear regulator controller driving an external PNP pass transistor.