Advantages of switching power supplies
The input of a switching power supply is mostly AC power (such as mains) or DC power, and the output is mostly equipment that requires DC power, such as a personal computer, and the switching power supply converts the voltage and current between the two.
The switching power supply is different from the linear power supply. Most of the switching transistors used by the switching power supply are switched between the fully open mode (saturation region) and the fully closed mode (cut-off region). These two modes have the characteristics of low dissipation. The conversion will have higher dissipation, but the time is very short, so it saves energy and generates less waste heat. Ideally, switching power supplies themselves consume no power. Voltage regulation is achieved by adjusting the turn-on and turn-off times of transistors. On the contrary, in the process of generating the output voltage of the linear power supply, the transistor works in the amplification area and consumes power itself.
The high conversion efficiency of the switching power supply is one of its major advantages, and because the switching power supply has a high operating frequency, a small-sized and light-weight transformer can be used, so the switching power supply is also smaller in size and lighter in weight than the linear power supply.
If the high efficiency, size and weight of the power supply are the key considerations, the switching power supply is better than the linear power supply. However, the switching power supply is more complicated, and the internal transistors will switch frequently. If the switching current is not processed, noise and electromagnetic interference may be generated to affect other equipment. Moreover, if the switching power supply is not specially designed, its power factor may not be high.
