What is the principle of switching power supply?
With the rapid development of power electronics technology, the relationship between power electronic equipment and people's work and life is becoming increasingly close, and electronic equipment is inseparable from a reliable power supply. In the 1980s, the computer power supply fully realized the switching power supply, and took the lead in completing the computer. In the 1990s, switching power supplies entered various electronic and electrical equipment fields one after another. 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 kind of power supply that uses modern power electronics technology to control the time ratio of switching transistor on and off to maintain a stable output voltage. Switching power supply is generally composed of pulse width modulation (PWM) control IC and MOSFET. Compared with the linear power supply, the cost of the switching power supply increases with the increase of the output power, but the growth rate of the two is 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, and this cost reversal point is increasingly moving to the low output power side, which provides a wide development space for switching power supply. The high frequency of switching power supply is the direction of its development. High frequency makes switching power supply miniaturized, and makes switching power supply enter a wider application field, especially in the application of high-tech fields, which promotes the miniaturization and portability of high-tech products change. In addition, the development and application of switching power supply are of great significance in saving energy, saving resources and protecting the environment.
The switching power supply is to use the circuit to control the switching tube to perform high-speed on and off. The direct current is converted into high-frequency alternating current and supplied to the transformer for voltage transformation, thereby generating one or more sets of voltages required! The reason for switching to Huawei's high-frequency AC is that the efficiency of high-frequency AC in the transformer transformation circuit is much higher than that of 50HZ. So the switching transformer can be made very small, and it is not very hot when working! The cost is very low. If you don't change 50HZ to high frequency, then switching power supply is meaningless! ! Switching transformers are not mysterious either. Just an ordinary transformer! This is a switching power supply. Switching power supplies can be roughly divided into two types: isolated and non-isolated. The isolated type must have a switching transformer, but the non-isolated one may not necessarily have it.
When the power is the same, the higher the switching frequency, the smaller the volume of the switching transformer, but the higher the requirements for the switching tube; the secondary of the switching transformer can have multiple windings or one winding has multiple taps to obtain the required Output; Generally, some protection circuits should be added, such as no-load, short-circuit and other protections, otherwise the switching power supply may be burned.
