Switch Mode Power Supply (SMPS), also known as switching power supply or switch converter, is a high-frequency electrical energy conversion device and a type of power supply. Its function is to convert a precise voltage into the voltage or current required by the user through different forms of architecture. The input of a switching power supply is mostly AC power (such as mains power) or DC power, while the output is mostly devices that require DC power, such as personal computers, and the switching power supply converts voltage and current between the two. Switching power supplies are different from linear power supplies. The switching transistors used in switching power supplies mostly switch between fully open mode (saturation zone) and fully closed mode (cutoff zone), both of which have the characteristic of low dissipation. The conversion between switches will have high dissipation, but the time is short, so it is more energy-efficient and produces less waste heat. Ideally, switching power supplies themselves do not consume electrical energy. Voltage stabilization is achieved by adjusting the time of transistor conduction and disconnection. On the contrary, in the process of generating output voltage in a linear power supply, the transistor operates in the amplification region and consumes electrical energy itself. The high conversion efficiency of switching power supplies is one of its major advantages, and because switching power supplies have a high operating frequency, they can use small-sized and lightweight transformers. Therefore, switching power supplies will also be smaller in size and lighter in weight than linear power supplies. If the high efficiency, volume, and weight of the power supply are key considerations, switching power supply is better than linear power supply. However, switching power supplies are relatively complex, with internal transistors frequently switching. If the switching current is not processed, it may generate noise and electromagnetic interference that affect other devices. Moreover, if the switching power supply is not specially designed, its power factor may not be high. Switching power supply products are widely used in industrial automation control, military equipment, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instruments and meters, medical equipment, semiconductor refrigeration and heating, air purifiers, electronic refrigerators, LCD displays, LED lighting fixtures, communication equipment, audio-visual products, security monitoring, LED light strips, computer chassis, digital products and instruments, and other fields