The main difference between switching power supply and linear power supply is their working mode.
The power regulating tube of linear power supply always works in the amplification area, and the current flowing through it is continuous. Because of the large power loss on the adjusting tube, it needs a large power adjusting tube and a large radiator, which causes serious heating and low efficiency. Generally, it is 40%~60%, and it has to be said that it is a good linear power supply. The working mode of linear power supply makes it necessary for him to change from high voltage to low voltage with a voltage regulator, which is usually a transformer, and there are other power supplies like KX, and then output DC voltage through rectification. In this way, his volume is also very large, relatively heavy, inefficient and calorific value is also large. He also has his advantages: small ripple, good adjustment rate and small external interference. Suitable for analog circuits, various amplifiers, etc.
Switching power supply. Its power device works in the switch state, and the energy is temporarily stored through the inductor when the voltage is adjusted, so that its loss is small, its efficiency is high, and its requirements for heat dissipation are low. However, it also has higher requirements for transformers and energy storage inductors, and it should be made of materials with low loss and high permeability. Its transformer is a word small. The total efficiency is 80% ~ 98%, and the switching power supply has high efficiency but small volume, but compared with the linear power supply, its ripple and voltage and current regulation rate are somewhat discounted.
Special requirements for AC power supply for radio communication such as amateur radio stations;
1. The radio station uses a relatively standard outdoor antenna feed system. When the coaxial cable shielding layer does not participate in radio transceiver, the ESD of the power supply and the anti-interference ability of the voltage stabilizing part of the power supply are mainly considered. The reason is that the load impedance of the power supply changes greatly at the moment of transmission, and if it is not handled properly, the sampling and execution of the voltage stabilizing system will be disordered, so a low-pass filter must be installed between the sampling and output of the voltage stabilizing system.
2. The radio station uses a casual outdoor antenna feed system, and the coaxial cable shield participates in radio transceiver. At this moment, it is necessary to install a low-pass filter at the 220V input to suppress interference.
3. When using expensive radio stations, due to the high maintenance cost, a parallel voltage limiting circuit must be installed to ensure that the voltage obtained by the radio station does not exceed 25% of the rated voltage at any time.
