What is a flyback transformer

What is a Flyback transformer

A flyback transformer is an integrated transformer, which has built-in integrated and divider networks and several low voltage windings. They are high-frequency ferrite core transformer which is used to generate a high voltage which is needed to operate a cathode ray tube device such as a television monitor and its voltage will be from a few kV to few tens of kV. Their operating frequency will be up to several tens of kHz.

Conventional flyback transformers have high voltage built-in diode in the outside, but nowadays flyback transformer comes in one piece and all the high voltage diodes are molded in the casing. In order to get some output from flyback transformer, a powerful high-frequency driver circuit is needed.

Types of Flyback transformer

First one is the AC old rectified type and it is not good for anything over 30KV due to its low number of turns in the secondary winding we won’t be able to get high voltages out of it

The second one is the best its secondary windings are divided into sections and it is separated by diodes. So there will be only a little AC voltage and by that insulating, it will be easier and the output voltage will be more

The third type is similar to the second and their only difference is it has a high voltage capacitor on its output

Overview of a flyback transformer

  • It is used for voltage isolation
  • Primary and secondary windings are linked by nearly the same magnetic flux
  • It has multiple output windings for generating multiple isolated voltages
  • Used for high power applications

How flyback transformer is different from a normal transformer

  • The secondary and the primary winding of a flyback transformer doesn’t conduct simultaneously
  • Magnetic design of a flyback transformer is almost like of an inductor
  • It will be suitable to call it as an inductor transformer

Operation of flyback transformer

Flyback transformer draws current from the power source, the current will increase over time the flow of current will also create a magnetic field flux the flux change over time will induce a voltage in flyback transformer if the current from the source is interrupted then the magnetic field will collapse and its direction will change. The term flyback is used for the reversal process, now the current will only be able to flow through the diode. And it will thus decline the magnetic field and it will create a flyback voltage and if the decline starts rapidly then the voltage will increase and this flyback action will create the required voltage to discharge the energy in the flyback transformer

Flyback transformer driver

This could provide higher output voltage but it is not too efficient above 100W at which the switching transistor gets very hot, heat sinks can be added to the switching transistor, drivers will be helpful to get output from the flyback transformer