Power switch ICs (integrated circuits) are electronic components that control the power for another device within the circuit. They are used to enable or disable a power rail. Power switches are often used to control the current to a USB connector to prevent short-circuiting. These switches provide protection for circuits which may experience overload or high operating temperatures. Load switches are active whenever the power is switched on and therefore offer low leakage currents. Load switches are often used instead of a MOSFET as they offer additional protection from a smaller package.
When choosing a power switch it is important to consider the current limit levels. These levels can be fixed or adjustable depending on the device. Power switch ICs come in a standard semiconductor package, such as a SOT-21, SSOP and PDIP.
High-side switches sit between the positive power line and the load. Low-side switches sit between the load and the ground. High-side switches are more commonly used in heavy-load applications where a short circuit is more likely at the ground. Low-side switches are often cheaper and ideal for when load is controlled through a high-speed PWM. There are also H-bridge switch ICs which require both high-side and low-side switches.
Intelligent power switches are ICs that are largely used in the automotive applications. They also play a big role in the “Smart Home” products. An Intelligent power switch combines multiple actions into a single process. They are used in PAC (Programmable Automation Controller), CNC (Computer Numerical Control) & PLC (Programmable Logic Controller), robotics, agricultural systems, security systems & used in green energy, like wind turbines.