The principle and characteristics of switching power supply
operational principle
The DC switching power supply consists of an input part, a power conversion part, an output part, and a control part. The power conversion part is the core of the switching power supply, which performs high-frequency chopping on unstable DC and completes the conversion function required for output. It mainly consists of a switching transistor and a high-frequency transformer. Figure 1 shows the schematic diagram and equivalent schematic diagram of a DC switching power supply, which is composed of a full wave rectifier, switching transistor V, excitation signal, freewheeling diode Vp, energy storage inductor, and filtering capacitor C. In fact, the core part of a DC switching power supply is a DC transformer.
characteristic
In order to meet the needs of users, major switch power supply manufacturers both domestically and internationally are committed to synchronously developing new types of highly intelligent components, especially by improving the losses of secondary rectification devices and increasing technology in power ferrite (Mn Zn) materials to improve the ability to obtain high magnetic properties at high frequencies and high magnetic flux densities. At the same time, the application of SMT technology has made significant progress in switch power supplies, Arrange components on both sides of the circuit board to ensure that the switching power supply is light, small, and thin. Therefore, the development trend of DC switching power supply is high-frequency, high reliability, low consumption, low noise, anti-interference, and modularization.
The disadvantage of DC switching power supply is that it has severe switching interference and weak ability to adapt to harsh environments and sudden faults. Due to the certain gap between domestic microelectronics technology, production technology of resistive and capacitive devices, and magnetic material technology and some technologically advanced countries, the production technology of DC switching power supplies is difficult, maintenance is troublesome, and the cost is high
