The role of high frequency transformer in switching power supply

             The role of high frequency transformer in switching power supply 

Switching transformer with its high conversion efficiency, small size, light weight and working voltage range is relatively wide and many other advantages, in the mobile phone charger, battery car charger and a variety of household appliances will be used in the switching power supply, then in the switching power supply, we always see a high frequency transformer, Today we will focus on this high frequency transformer and talk about its role in switching power supply.

Working principle of switching power supply

We know that there are two types of switching power supply: self-excited switching power supply and other excited switching power supply. Now we take the other excited switching power supply as an example to illustrate its working process, so that we can further explain the role of high-frequency transformer in the switching power supply. In the other excited switching power supply, an independent oscillator generates a control pulse signal to control the on-off and off-off of the switching tube. When the switch is in the on-off state, the electromotive force will be generated in the primary winding of the high-frequency transformer, so that it will be induced to the secondary winding, and the electromotive force on the secondary winding will charge the electrolytic capacitor through the VD2 diode. This electrolytic capacitor acts as a filter so that the load PL will wait until a steady DC voltage is reached.

The role of high-frequency transformers used in switching power supplies

The first point is that the use of high-frequency transformers in switching power supply is to improve the conversion efficiency of the power supply. Because the high-frequency transformer its iron core is silicon steel core, this silicon steel sheet magnetic performance is very good, can greatly improve the resistivity and permeability so as to improve the switching power conversion efficiency, increase its output power.

The second point is to protect the back of the load and personal safety, played the role of safety isolation, but also purify the high-voltage power supply to prevent interference. It is assumed that the output voltage of the switching power supply is too high for some reason during operation, so that the excessive voltage will be sent to the protection circuit. Then the protection circuit in the switching power supply will open the protection mode, and it will "command" the switching tube to stop working. Once the switching tube stops working, the first winding end of the high-frequency transformer cannot generate electromotive force. In this way, the secondary winding of the high-frequency transformer can not get the induced electromotive force, and there is no voltage output at the output end, so as to protect the load from high voltage damage. If you do not use high frequency transformer once this phenomenon will be very dangerous, if the switch tube is broken down, high voltage direct output in electrical appliances, directly burned electrical appliances, and even endanger people's lives.

Shenzhen YLZ Technology Co., Ltd. specializes in the design and production of various types of high-frequency transformer, low-frequency (pulse, isolation) transformer, inductor coil. More relevant transformer knowledge, you can consult YLZ technology company's senior design engineer Zou Gong.