Switch Mode Power Supply (SMPS), also known as Switched Mode Power Supply (SMPS), is a high-frequency electrical energy conversion device, and is a type of power supply. Its function is to convert one bit of voltage into the voltage or current required by the user through different types of architectures. 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 the voltage and current between the two. Switching power supplies are different from linear power supplies in that the switching transistors used in switching power supplies are mostly switched between fully open mode (saturation zone) and fully closed mode (cutoff zone), both of which have the characteristic of low dissipation. Ideally, the switching power supply itself does not consume power. Voltage regulation is achieved by adjusting the on and off time of the transistor. Conversely, a linear power supply consumes electrical energy while the transistors are working in the amplification zone during the generation of the output voltage. The high conversion efficiency of switching power supplies is one of their major advantages, and because switching power supplies operate at high frequencies, they can use smaller, lighter transformers, so they are also smaller and lighter than linear power supplies.
Switching power supply products are widely used in industrial automation control, scientific research equipment, LED lighting, industrial control equipment, communication equipment, power equipment, instrumentation, medical equipment, semiconductor refrigeration and heating, air purifiers, electronic refrigerators, liquid crystal displays, LED lamps, communication equipment, audio-visual products, security monitoring, LED lights, computer cases, digital products and instruments and other fields.