Switching mode power supply, also known as switching power supply or switching converter, is a high-frequency power conversion device and a type of power supply. Its function is to convert a voltage level into the voltage or current required by the user through different forms of architecture.
The input of the switching power supply is mostly AC power (such as mains) or DC power, and the output is mostly equipment that requires DC power, such as personal computers, and the switching power supply converts the voltage and current between the two.
The advantages of the switching power supply are small size, light weight, stability and reliability; the disadvantage is that the ripple is larger than that of the linear power supply (generally ≤1%VO(P-P), and the good ones can reach more than ten mV(P-P) or less). Its power can range from a few watts to several kilowatts.
The general customary classification of switching power supplies are:
1. AC/DC power supply
This type of power supply is also called primary power supply - AC is alternating current, DC is direct current. It obtains energy from the power grid, and obtains a DC high voltage after high-voltage rectification and filtering, which is used for the DC/DC converter to obtain one or several stable DC voltages at the output end.
There are products with power ranging from a few watts to several kilowatts, which are used in different occasions. There are many specifications and models of such products, depending on user needs. The primary power supply in the communication power supply (AC220 input, DC48V or 24V output) also belongs to this category.
2. DC/DC power supply
It is also called secondary power supply in the communication system. It is provided by a primary power supply or a DC battery pack to provide a DC input voltage, and obtains one or several DC voltages at the output end after DC/DC conversion.
3. Communication power supply
The communication power supply is essentially a DC/DC converter power supply, but it is generally powered by DC -48V or -24V, and uses a backup battery as a backup for DC power supply, converting the DC power supply voltage into the working voltage of the circuit. Generally, it is divided into three types: central power supply, layered power supply and single-board power supply, and the latter has the highest reliability.
4. Radio power supply
The radio power supply inputs AC220V/110V and outputs DC13.8V. The power depends on the power of the power supply station, and there are products with several amperes and hundreds of amperes. In order to prevent the AC power grid from affecting the work of the radio, a battery pack is needed as a backup. Therefore, in addition to outputting a 13.8V DC voltage, this type of power supply also has an automatic conversion function for battery charging.
5. Module power supply
With the rapid development of science and technology, the requirements for power supply reliability and capacity/volume ratio are getting higher and higher. Module power supply is increasingly showing its superiority. It has high operating frequency, small size, high reliability, and is easy to install and combine for expansion, so it is becoming more and more widely used.
6. Special power supply
High voltage and low current power supply, high current power supply, 400Hz input AC/DC power supply, etc. can be classified into this category and can be selected according to special needs.
Products are widely used in industrial automation control, military equipment, scientific research equipment, industrial control equipment, computers and computers, communication equipment, power equipment, instruments and meters, medical equipment, semiconductor refrigeration and heating and other fields.
