The Function of High Frequency Transformers in Power Supply Switching
Switching transformers have many advantages such as high conversion efficiency, small size, light weight, and wide operating voltage range. They are used in mobile phone chargers, battery car chargers, and various household appliances. Therefore, in switching power supplies, we always see a high-frequency transformer. Today, we will talk about its role in switching power supplies based on this high-frequency transformer.
Working principle of switching power supply
We know that there are two types of switching power supplies: self-excited switching power supplies and self-excited switching power supplies. Now, let's take the self-excited switching power supply as an example to illustrate its working process, so that we can further explain the role of high-frequency transformers in switching power supplies. In a separate excitation switching power supply, an independent oscillator generates a control pulse signal to control the conduction and disconnection of the switch tube. When the switch tube V is in the switching state, there will be electromotive force generated on the primary winding of the high-frequency transformer, which will be sensed on the secondary winding. The electromotive force on the secondary winding is charged by the VD2 diode to the electrolytic capacitor, which plays a filtering role, This will wait for a stable DC voltage on the load RL.
The Function of High Frequency Transformers Used in Switching Power Supplies
I think high-frequency transformers have two main functions in switching power supplies. Let's talk about them separately. The first point is that using high-frequency transformers in switching power supplies is to improve the conversion efficiency of the power supply. Due to the use of silicon steel core as the iron core of high-frequency transformer, this silicon steel sheet has excellent magnetic conductivity, which can greatly improve the resistivity and permeability, thereby improving the conversion efficiency of switching power supply and increasing its output power.
The second point is to protect the safety of the load and personnel behind, playing a safe isolation role, while also purifying the high-voltage power supply to prevent interference. We assume that the output voltage of the switching power supply is too high due to some reason during operation, and the excessive voltage will be sent to the protection circuit. The protection circuit in the switching power supply will activate the protection mode, which will "command" the switch tube to stop working. Once the switch tube stops working, the primary winding end of the high-frequency transformer cannot generate electromotive force, In this way, the secondary winding of the high-frequency transformer cannot obtain the induced electromotive force, and there is no voltage output at the output end, thus protecting the load from high voltage damage. If high-frequency transformers are not used, this phenomenon can be very dangerous. If the switch tube is broken down, the high voltage will be directly output to the electrical appliance, directly burning the electrical appliance, and even endangering human life safety.
