1. Low power consumption and high efficiency. In the switching power supply circuit, the transistor V is alternately operated in the on-off and off-on switching states under the excitation of the excitation signal, and the conversion speed is fast, and the frequency is generally about 50 kHz, in some technologically advanced countries. It can be done at a few hundred or nearly 1000 kHz. This makes the switching transistor V consume very little power, and the efficiency of the power supply can be greatly improved, and its efficiency can reach 80%.
2. Small size and light weight. From the block diagram of the switching power supply, it can be clearly seen that no heavy power frequency transformer is used here. Since the dissipation power on the adjustment tube V is greatly reduced, a large heat sink is omitted. Due to these two reasons, the switching power supply is small in size and light in weight.
3. Wide voltage regulation range. The output voltage from the switching power supply is regulated by the duty cycle of the excitation signal, and the change in the input signal voltage can be compensated by frequency modulation or widening. In this way, when the voltage of the power frequency grid changes greatly, it can still ensure a relatively stable output voltage. Therefore, the switching power supply has a wide voltage regulation range and the voltage regulation effect is very good. In addition, methods for changing the duty ratio include pulse width modulation type and frequency modulation type. The switching power supply not only has the advantage of wide voltage regulation range, but also has many methods for realizing voltage regulation. Designers can flexibly select various types of switching power supplies according to the requirements of practical applications.
The efficiency of filtering is greatly improved, so that the capacity and volume of the filter capacitor are greatly reduced. The operating frequency of the switching power supply is basically working at 50 kHz, which is 1000 times that of the linear regulated power supply, which makes the filtering efficiency after rectification almost 1000 times. Even after half-wave rectification and capacitor filtering, the efficiency is improved. 500 times. Under the same ripple output voltage, when the switching power supply is used, the capacity of the filter capacitor is only 1/500~1/1000 of the filter capacitor in the linear regulated power supply. The circuit form is flexible and diverse, and there are self-excited and other excited modes. Wide-band and FM-type, single-ended and double-ended, etc., designers can play the characteristics of various types of circuits, design a switching power supply that can meet different applications.