The direction of development of modern power electronics technology is to shift from traditional power electronics, which is based on low-frequency technology to deal with problems, to modern power electronics, which is based on high-frequency technology to deal with problems. And in the application of power electronics technology and a variety of power systems, switching power supply technology are in the core position.

1, linear power supply cost at a certain output power point, but higher than the switching power supply.

2, power electronic equipment and people's work, life is increasingly close, and electronic equipment are inseparable from a reliable power supply, into the 80's after the computer fully realised switching power supply, to the 90's switching power supply successively into a variety of electronic and electrical fields.

3, in fact, from the schematic diagram of the switching power supply can be understood: it does not use the bulky industrial frequency transformer, at the same time because the adjustment tube on the dissipation of power is greatly reduced, thus eliminating the need for larger heat sinks. This makes the switching power supply becomes smaller and lighter. However, the biggest advantage of switching power supply is - low power consumption and high efficiency. In the switching power supply circuit, the transistor in the excitation signal, it constantly repeats the 'on' 'as of' switching state, the conversion speed is very fast, the frequency in 50HZ only, making the power supply efficiency greatly improved.

4, switching power supply voltage regulator wide range. The output voltage from the switching power supply is the duty cycle of the excitation signal to regulate, the input signal signal voltage change can be compensated by frequency or width adjustment. In this way, in the industrial frequency grid voltage changes are large, it can still ensure a more stable output voltage.

5, switching power supply operating frequency is basically working at 50kHz, is a linear regulated power supply 1000 times, which makes the rectifier filtering efficiency almost 1000 times; even with half-wave rectification with capacitor filtering, the efficiency is also increased by 500 times. In the same ripple output voltage, the use of switching power supply, the capacity of the filter capacitor is only linear regulated power supply filter capacitor 1/500 ~ 1/1000.