Basic Principles of Switching Mode Power Supplies
With the development of power electronics technology, the relationship between power electronic equipment and people's work and life has become increasingly close. Electronic devices cannot do without reliable power sources. In the 1980s, computer power supplies were fully converted into switch mode power supplies, leading to the replacement of computer power supplies. In the 1990s, switch mode power supplies entered various fields of electronic and electrical equipment, and were widely used in power supplies for program-controlled switches, communication, electronic detection equipment, control equipment, etc., which further promoted the rapid development of switch mode power supply technology. Switching power supply is a type of power supply that uses modern power electronics technology to control the time ratio of the on and off of the switching transistor, maintaining a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. Compared to linear power supplies, the cost of both switching power supplies increases with the increase of output power, but their growth rates are different. The cost of a linear power supply is actually higher than that of a switching power supply at a certain output power point, which is the cost reversal point. With the development and innovation of power electronics technology, switching power supply technology is constantly innovating, and this cost reversal point is increasingly moving towards the low output power end, providing a wide range of development space for switching power supplies. The high-frequency development of switching power supplies is the direction of their development. High frequency makes switching power supplies smaller and enables them to enter a wider range of application fields, especially in high-tech fields, promoting the miniaturization and lightweight of high-tech products. In addition, the development and application of switch mode power supplies are of great significance in energy conservation, resource conservation, and environmental protection.
Switching power supply is used to control the switching tubes through circuits for high-speed on/off. It converts direct current into high-frequency alternating current and provides it to transformers for transformation, thereby generating one or more sets of required voltages! The reason for switching to high-frequency AC power is that the efficiency of high-frequency AC power in transformer transformation circuits is much higher than 50HZ. Therefore, switching transformers can be made very small and not very hot during operation! The cost is very low. If 50HZ is not converted to high frequency, then the switching power supply is meaningless!! Switching transformers are not mysterious. They are just ordinary transformers! This is a switch power supply. Switching power supplies can generally be divided into two types: isolated and non isolated. The isolated type must have a switching transformer, while the non isolated type may not necessarily have one.
