7.1 Overview

The inline protection functionality of the TPS2490 is designed to control the inrush current to the load upon insertion of a circuit card into a live backplane or other hot power source, thereby limiting the voltage sag on the backplane's supply voltage and the dV/dt of the voltage applied to the load. Effects on other circuits in the system are minimized, preventing possible unintended resets. A controlled shutdown when the circuit card is removed can also be implemented using the TPS2490.

In addition to a programmable current limit, the TPS2490 monitors and limits the maximum power dissipation in the series pass device to maintain operating within the device Safe Operating Area (SOA). Either current limiting or power limiting for an extended period of time results in the shutdown of the series pass device. In this event, the TPS2490 will latch off while the TPS2491 will retry an infinite number of timer to recover after the fault is removed. Programmable EN circuit shuts down the TPS2490 when the system input voltage falls below the desired operating range.