A switched-mode power supply is a power supply unit that incorporates a switching regulator that converts a power source with high efficiency. In the process of obtaining output power from input power using a power converter, a switching element converts and adjusts power. Switched-mode power supplies have several rotary types. There are large sizes, insulated flyback methods in which a large current flows through the capacitor, non-insulated types, buck-boost type circuits capable of step-up / step-down, full-bridge methods with a multi-stone basic switch arm, etc. There are also differences due to adjustable features such as constant power, constant current, constant voltage, etc. Also, there are devices with functions such as monitoring power supplies and voltage, functions with high efficiency and long life due to reduced power loss, and more compact devices.