Flyback Transformers
Lithentic offers Off The Shelf Through hole Flyback transformers for switching, isolation, capacitor charging, impedance matching, gate drive or pulse transformer applications. Our power converter transformers for DC-DC and AC-DC voltage conversion are appropriate in industrial, automotive and high-reliability environments. Our flyback transformers are specially designed to achieve tight coupling and come in a wide range of impedance ratios for low power applications.
Please reach out to us for custom magnetic design, we have state of the art design and testing setup supported by experienced team to resolve your every need.
Characteristics of Flyback Topology:
The Flyback transformer:
- Provides electrical isolation in between primary and secondary circuits
- Behaves like coupled inductors working in Buck-Boost mode
- Stores magnetic energy in transformer core during On state of PWM cycle
- Transfers the stored energy to the secondary circuit during Off state of PWM cycle
- A Snubber Circuit is essential to prevent high voltage buildup across switching MOSFET terminals
- The stored energy in flyback transformer improves the load power transfer efficiency in secondary circuit
- The CCM (Continuous Conduction Mode) or DCM (Discontinuous Conduction Mode) of secondary current can be controlled by simply changing the duty cycle of PWM input at primary side switching MOSFET
Typical Application Scenarios
Flyback Converter
The basic Flyback Converter consists of a ferrite core transformer having one primary coil, one secondary coil, primary side switching circuit and secondary side filter and load circuits. The switching frequency is kept high, in the range of 10KHz to 150KHz to keep the transformer size small. There are varieties of soft ferrite based materials available in the market suitable for different applications in this frequency range. Some of them can be named as Ni-Zn, Mn-Zn, iron powder, sendust etc. along with their different blends and mixes. Each of these core materials are characterized by their saturation flux density, initial permeability, temperature range etc.
As shown in above circuit diagram the primary winding is driven by a DC source through a switching device. The input DC voltage Vin is switched On and Off periodically by applying PWM signal at the gate terminal of MOSFET Q1.
Flyback Converter with Primary Side Feedback
Parallel Connection of Two Forward Converters
