High-frequency transformers

High-frequency transformers are the most important component of a switching power supply. There are many topologies in switching power supplies. For example, the half-bridge power conversion circuit operates by having two switching transistors alternately conduct to generate a 100kHz high-frequency pulse wave. Then, it is stepped down through a high-frequency transformer and outputs alternating current. The number of turns in each winding of the high-frequency transformer determines the output voltage.

 In a typical half-bridge power conversion circuit, the most prominent ones are three high-frequency transformers: the main transformer, the driver transformer, and the auxiliary transformer (standby transformer). Each type of transformer has its own measurement standards as stipulated by the country. For example, for the main transformer, if the power supply is above 200W, the diameter (height) of the magnetic core must not be less than 35mm. While for the auxiliary transformer, when the power of the power supply does not exceed 300W, its magnetic core diameter of 16mm is sufficient.