Introduction of Flyback Transformer Design Tool
The main winding of the flyback transformer is electrified when the switching transistor in a flyback converter is turned on. However no energy is delivered to the secondary windings. The field collapses when the transistor is switched off, and the energy is transmitted to the secondary windings. When the switching transistor is switched on, energy is transmitted to the secondary windings, as opposed to a forward converter topology, in which energy is sent to the secondary windings when the switching transistor is turned on. By comparing the orientation of the dots on the secondary to the primary, you can discern the difference between the two topology. The dots in the flyback converter are inverted, whereas the dots in the forward converter are aligned.
For the different windings of a discontinuous mode flyback converter, the flyback transformer design tool above will help you to calculate the number of wire gauge, inductance and turns. In fact, this flyback converter tool is a online flyback transformer calculation tool.
How is Flyback Voltage Calculated
This following Youtube video explains the current flow and operation of the flyback converter with the active switch on and off in continuous conduction mode (CCM) and average steady state. You can follow its instruction to calculate the flyback voltage. Of course, you can use our online flyback transformer calculator to do the flyback voltage calculation.
Flyback Converter Operation and Voltage Equation
Flyback Controller Overview
During the first half of the switching cycle, energy is stored in the magnetic field of the transformer, and then released to the secondary winding(s) linked to the load during the second half of the cycle. The gapped-core structure of flyback transformers allows for significant energy storage without saturating the core. Flybacks are distinct from other topologies, such as forward-mode, in which energy passes from primary to secondary quickly. Because they have a gapped core and store energy in the core, flyback transformers are also classified as coupled inductors.
What is a Flyback Transformer?
A flyback transformer is a gapped-core coupled inductor. When the input voltage is delivered to the primary winding during each cycle, energy is stored in the gap of the core. The energy is subsequently transmitted to the secondary winding, which powers the load. Flyback transformers are used in flyback converters to enable voltage transformation and circuit isolation.
For cost-effective, high-efficiency isolated power supply solutions up to 120 Watts, flyback transformers are the most preferred choice. They give circuit isolation, several output options, and the ability to output positive or negative voltages. They can also be controlled over a broad variety of input voltages and loads. The flyback topology, unlike the other isolated topology, does not require a separate output filter inductor since energy is stored in the transformer. This decreases the number of components required and simplifies the circuit design.
How to Make a Flyback Transformer Circuit?
The following video shows you with Flyback transformer design instruction on how to design a flyback transformer. This method will use our Flyback transformer design tool.
How Does a Flyback Transformer Work?
The transformer provides isolation and, if needed, voltage transformation by turns ratio in the flyback architecture, which is based on a buck-boost topology. A Metal Oxide Semiconductor Field Effect Transistor (MOSFET) is the most frequent switch (SW) in a flyback converter. However silicon carbide (SiC), bipolar transistors and gallium nitride (GaN) are also used on occasion. To obtain the needed output voltage, the flyback controller opens and shuts the switch with the proper duty cycle. Flyback transformers often have a duty cycle of less than 0.5. To obtain the needed output voltage, several combinations of turns ratios and duty cycles can be employed.
Example of Flyback Circuit
The following is a flyback SMPS circuit, which will raise voltage from roughly 20V to 40V. If you change the feedback resistors, the voltage will become more.
The LM3479 controller is useful because it allows you to change R1 to adjust the frequency of operation. And it has a frequency of around 500kHz at 39K. One of this flyback circuit's unique features is that the Flyback Switch Mode Regulator is powered by +5V, a lower voltage than VPIN. Because the regulator voltage source is separate from the coil voltage supply, VPIN can be practically any value. Of course, the 5V must be generated somewhere else.
On the drain of the MOSFET, there is additionally a non-dissipative circuit to reduce voltage spikes when the Flyback transistor switches off.
Applications of Typical Flyback Transformer
Flyback transformers can be used in a variety of situations. For example, AC-DC power supplies, DC-DC power supplies, Battery charging, Capacitor charging, LED Lighting (Light Emitting Diodes), PoE (Power over Ethernet), Solar Microinverters and Telecom (telecommunications).
For many applications where cheap cost, compact size, and high efficiency are required, off-the-shelf flyback transformers are available. They are often used in DC-DC controllers in the telecom (telecommunications) voltage range of 37-72Vdc, with extended voltages extending from 2–400 Vdc, as well as the universal AC line input voltage range of 85–265 Vac.
Flyback transformers are often utilized for output currents and power levels below 10 amps and 100 watts. Standard off-the-shelf flyback transformers from Coilcraft range in power from a few Watts to roughly 120 Watts. Forward-mode, push-pull, or full-bridge/half-bridge topologies become more efficient when larger current and power are required.
Introduction of Flyback Converters
The flyback converter is a power supply architecture that employs a mutually linked inductor to store energy while current flows through it and release it when the power is turned off. In terms of construction and performance, flyback converters are comparable to booster converters. The main winding of the transformer, on the other hand, serves as an inductor, while the secondary supplies the output. The main and secondary windings are used as two distinct inductors in the flyback design.
Flyback converter design explained YouTube Video
The above YouTube video about flyback converter will explain the basic principles of flyback converter. And it can show your the process to design flyback transformer. So you can follow it if you want to make a flyback transformer circuit.
