How much do you know about switching power supplies?
Switch Mode Power Supply (SMPS), also known as Switching Power Supply or Switching Converter, is a high-frequency electrical energy conversion device and a type of power supply. Its function is to convert a level voltage into the voltage or current required by the user end 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. Switching power supplies convert the voltage and current between the two.
Switching power supplies are different from linear power supplies. The switching transistors used in switching power supplies are mostly switched between fully open mode (saturation region) and fully closed mode (cutoff region), both of which have the characteristic of low energy dissipation. The conversion between switching modes will have high dissipation, but the time is short, so it is more energy-efficient and generates less waste heat. Ideally, a switching power supply itself does not consume electrical energy. Voltage stabilization is achieved by adjusting the on-time and off time of transistors. On the contrary, in the process of generating output voltage, the transistor of a linear power supply operates in the amplification region and consumes electrical energy itself. The high conversion efficiency of switching power supplies is one of their major advantages, and because switching power supplies have a high operating frequency, they can use small-sized and lightweight transformers. Therefore, switching power supplies are also 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, switch mode power supply is better than linear power supply. However, switch mode power supplies are relatively complex, with frequent switching of internal transistors. If the switching current is still processed, it may generate noise and electromagnetic interference that can affect other devices. Moreover, if the switch mode power supply is not specially designed, its power factor may not be high.
