Switched DC regulated power supply:
Different from linear regulated power supply, a kind of stable power supply is switched DC regulated power supply. Its circuit types mainly include single-ended flyback, single-ended forward, half-bridge, push-pull and full-bridge. The fundamental difference between it and linear power supply is that its transformer does not work at power frequency, but works at tens of kilohertz to several megahertz. The function tube works either in saturation or in cut-off zone, i.e. in switching state; the switching power supply is named for it. The advantages of switching power supply are small size, light weight, stability and reliability. The disadvantages of switching power supply are larger ripple than linear power supply (generally less than 1% VO (P-P), good can achieve more than a dozen mV (P-P) or smaller. Its power can be produced from several kilowatts to several kilowatts. The price range is from 3 yuan to more than 100,000 yuan per watt. Here are some kinds of switching power supply according to the general custom classification.
1, AC/DC power supply
This kind of power supply is also called primary power supply-AC is AC, DC is DC. It obtains energy from the power grid, and obtains a DC high voltage through high voltage rectifier filter. It can be used for DC/DC converter to obtain one or more stable DC voltage at the output end. The power can be produced from several watts to several kilowatts, which can be used in different occasions. There are many specifications and models of this kind of products, and the primary power supply (AC220 input, DC48V or 24V output) of the communication power supply is also of this kind according to the needs of users.
2, DC/DC power supply
In communication system, it is also called secondary power supply. It is provided by primary power supply or DC battery pack with a DC input voltage. After DC/DC conversion, one or more DC voltages are obtained at the output.
3, communication power supply
Communication power supply is essentially DC/DC converter power supply, but it is usually supplied by DC-48V or-24V, and backup battery is used as DC power supply. The DC power supply voltage is converted into circuit working voltage. Generally, it is divided into central power supply, layered power supply and single board power supply. The latter has the highest reliability.
4, radio power supply
Radio power supply input AC220V/110V, output DC13.8V, power is determined by the power supplied by the station, Gui'an several hundred amperes have products. In order to prevent AC grid power outage from affecting the work of the station, batteries are needed as backup, so this kind of power supply not only outputs a 13.8V DC voltage, but also has the function of automatic battery charging conversion.
5, module power supply
With the rapid development of science and technology, the requirement of power supply reliability, capacity/volume ratio is higher and higher. Modular power supply shows its advantages more and more. It has high working frequency, small size, high reliability, easy to install and expand, so it is more and more widely used. At present, although there are corresponding module production in our country, the failure rate is high because the production technology can not catch up with the international level.
DC/DC module power supply is currently expensive, but judging from the overall cost of the product's long application cycle, especially the high maintenance cost and goodwill loss caused by system failure, it is economical to choose this power supply module. It is also worth mentioning here that the Roche converter circuit, whose outstanding advantage is electricity. The circuit has simple structure, high efficiency and close to zero ripple value of output voltage and current.
6. Special power supply
High voltage low current power supply, high current power supply, 400 Hz input AC/DC power supply, etc. can be classified into this type, can be selected according to special needs. The price of switching power supply is generally 2-8 yuan/watt. The price of special low-power and high-power power supply is slightly higher, up to 11-13 yuan/watt.