Principle and maintenance of switching power supply-EEWORLD Training

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Switching power supply is an indispensable circuit for many electrical appliances. Do you have an in-depth understanding of its working principle during maintenance? I hope you may wish to carefully watch this video tutorial on the principle and maintenance of switching power supply provided by this site. Encyclopedia: A switching power supply is a power supply that uses modern power electronics technology to control the turn-on and turn-off time ratio of the switch tube to maintain a stable output voltage. The switching power supply is generally composed of a pulse width modulation (PWM) control IC and a MOSFET. Compared with switching power supplies and linear power supplies, the cost of both increases with the increase in output power, but the growth rates are different. At a certain output power point, the cost of linear power supplies is higher than that of switching power supplies. This point is called the cost reversal point. With the development and innovation of power electronics technology, switching power supply technology is also constantly innovating. This cost reversal point is increasingly moving to the low-output power end, which provides a broad development space for switching power supplies.

With the rapid development of power electronics technology, power electronic equipment is increasingly closely related to people's work and life, and electronic equipment is inseparable from reliable power supply. In the 1980s, computer power supplies fully realized switching power supply, taking the lead in completing the development of computers. In the 1990s, switching power supplies have entered various electronic and electrical equipment fields. Program-controlled switches, communications, electronic testing equipment power supplies, control equipment power supplies, etc. have widely used switching power supplies, which has promoted the rapid development of switching power supply technology. . Switching power supply is a power supply that uses modern power electronics technology to control the turn-on and turn-off time ratio of switching transistors to maintain a stable output voltage. Switching power supplies are generally composed of pulse width modulation (PWM) control ICs and MOSFETs. Compared with switching power supplies and linear power supplies, the cost of both increases with the increase in output power, but the growth rates are different. At a certain output power point, the cost of linear power supply is higher than that of switching power supply, which is the cost reversal point. With the development and innovation of power electronics technology, switching power supply technology is constantly innovating. This cost reversal point is increasingly moving to the low-output power end, which provides a wide range of development space for switching power supplies.

High frequency of switching power supply is the direction of its development. High frequency makes switching power supply miniaturized and allows switching power supply to enter a wider range of application fields, especially in high-tech fields. It promotes the miniaturization and lightweight of high-tech products. change. In addition, the development and application of switching power supplies are of great significance in saving energy, saving resources and protecting the environment.

There are two types of modern switching power supplies: one is DC switching power supply; the other is AC switching power supply. What is mainly introduced here is only the DC switching power supply. Its function is to convert the original power supply (coarse power) with poor power quality, such as mains power or battery power, into a higher quality DC voltage (fine power) that meets the requirements of the equipment. . The core of the DC switching power supply is the DC/DC converter. Therefore, the classification of DC switching power supplies relies on the classification of DC/DC converters. In other words, the classification of DC switching power supplies is basically the same as the classification of DC/DC converters. The classification of DC/DC converters is basically the classification of DC switching power supplies.

DC DC/DC converters can be divided into two categories according to whether there is electrical isolation between input and output: one type is isolated and is called isolated DC/DC converter; the other type is without isolation and is called non-isolated type. DC/DC converter.

Isolated DC/DC converters can also be classified according to the number of active power devices. There are two types of single-tube DC/DC converters: forward and flyback. Double-tube DC/DC converters include Double-tube Forward Converter, Double-tube Flyback Converter, Push-Pull Converter and Half-Bridge Converter. Four kinds. The four-tube DC/DC converter is a full-bridge DC/DC converter (Full-Bridge Converter).

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