The simple current-limiting load switch shown in Figure 1 will be familiar to most readers. In this circuit, a high level signal applied to the input switches on MOSFET Q2, which energizes the load.

The ability to turn on loads in a controlled manner is important in applications where the power budget is limited. Hard switching a load can cause the input power rail to droop and result in a fault.

A load switch is an electronic switch. It works like a relay to power supply rails in systems, but it has no moving parts. Load switches are increasingly found in today’s portable electronic devices, ...

Biometric sensor modules can take advantage of the Intellimax FPF2024, FPF2025, FPF2026, and FPF2027 advanced load switches from Fairchild Semiconductor, which provide a 1-µA quiescent current.