What Is The Switching Power Supply?

- Jun 15, 2018-

What is the Switching power supply?


Heater Switch.jpgSwitching power supply is a type of power supply that uses modern power electronics to control the turn-on and turn-off time of the switch and maintain a stable output voltage. The switching power supply is generally composed of a pulse width modulation control IC and a MOSFET. Compared with the linear power supply, the cost of both of the switching power supply and the linear power supply increases as the output power increases, but the growth rates of the two are different. The linear power supply costs at a certain output power point but is higher than the switching power supply, which is called the cost reversal point. With the development and innovation of power electronics technology, switching power supply technology is also constantly innovating, and this cost reversal point is increasingly moving to low-power output terminals, which provides a broad space for the development of switching power supplies.

The high frequency of the switching power supply is the direction of its development. The high frequency of switching power supply miniaturization and switching power supply into a wider range of applications, especially in the application of new technologies, has promoted the miniaturization and lightweight of new technology products. Change. In addition, the development and application of switching power supply are of great significance in energy conservation, resource conservation and environmental protection. Power electronics used in switching power supplies are mainly diodes, IGBTs, and MOSFETs. SCR has a few applications in the switching power supply input rectification circuit and soft start circuit, GTR drive is difficult, the switching frequency is low, and gradually replaced by IGBT and MOSFET.


The switching power supply generally has three operating modes: frequency, fixed pulse width mode, fixed frequency, variable pulse width mode, variable frequency and pulse width mode. According to the way the switching devices are connected in the circuit, the widely used switching power supplies can be roughly classified into three major categories: series-connected switching power supplies, parallel-connected switching power supplies, and transformer-type switching power supplies. Among them, the transformer-type switching power supply (hereinafter referred to as the transformer switching power supply) can be further divided into: push-pull, half-bridge, full-bridge and other types; according to the transformer's excitation and output voltage phase, can be divided into: forward excitation , Flyback, single-excited, and double-excited, etc.; if it is divided from the use, it can be divided into more categories.