1-1. What is a load switch IC?

A load switch IC is a semiconductor switch inserted in series between a power supply and a load circuit or IC. The use of load switch ICs simplifies: 1) the supplying of power to each system block, 2) power supply sequencing for ICs, and 3) circuit protection from system failure.
Take, for example, mobile devices and energy-saving equipment powered by a lithium-ion or other type of battery. These electronic systems save power by enabling only the essential circuit blocks and shutting down all the others.
Load switch ICs are power management ICs with an internal switch that exhibit a minimal voltage drop and power dissipation because of low on-resistance and low quiescent current. Load switch ICs help improve the stability and reduce the size of an electronic system because they incorporate various protection functions and require fewer components than a load switch circuit composed of discrete devices.