Knowledge introduction of switching power supply
The main working principle of the switching power supply is that the Mos tubes of the upper bridge and the lower bridge are turned on in turn. First, the current flows in through the Mos tube of the upper bridge, and the electric energy is accumulated in the coil by using the storage function of the coil. Finally, the Mos tube of the upper bridge is turned off, and the lower bridge is turned on. The Mos tube, coil and capacitor of the bridge continuously supply power to the outside. Then turn off the lower bridge Mos tube, and then open the upper bridge to let the current enter, and repeat like this, because the Mos tube needs to be switched on and off in turn, so it is called a switching power supply.
The linear power supply is different. Since there is no switch involved, the upper water pipe is always discharging water. If there is too much water, it will leak out. This is what we often see in some linear power supplies. The Mos tube generates a lot of heat. The endless electrical energy is all converted into heat energy. From this point of view, the conversion efficiency of the linear power supply is very low, and when the heat is high, the life of the components is bound to decrease, affecting the final use effect.
The difference between a switching power supply and a linear power supply is mainly the way they work.
The power device of the linear power supply works in a linear state, that is to say, the power device is always working when it is used, so it leads to its low working efficiency, generally between 50[[%]]~60[[%]], and It must be said that he is a very good linear power supply. The working method of the linear power supply makes it necessary to have a voltage device to change from high voltage to low voltage. Generally, it is a transformer, and there are others like KX power supply, which then rectifies and outputs DC voltage. As a result, his volume is large, heavy, low in efficiency, and generates a lot of heat. He also has his advantages: small ripple, good adjustment rate, and small external interference. Suitable for use with analog circuits, various amplifiers, etc.
switch power supply. Its power devices work in the switching state, (one on and one off, one on and one off, the frequency is very fast, the frequency of general panel switching power supply is 100~200KHz, and the frequency of module power supply is 300~500KHz). In this way, its loss is small and its efficiency is high. There are also requirements for transformers, which must be made of materials with high magnetic permeability. A little bit of ink, his transformer is a small word. Efficiency 80% to 90%. It is said that the best VICOR modules in the United States are as high as 99%. The switching power supply has high efficiency and small size, but compared with the linear power supply, its ripple and voltage and current adjustment rate are discounted.
