Flyback Converter
Connector
Filter Capacitor
Keep DC-Bias and SRF in mind when selecting MLCCs for filtering.
Filter Capacitor
Keep DC-Bias and SRF in mind when selecting MLCCs for filtering.
Differential Mode Filter
Differential mode noise < 30MHz is best attenuated by ferrite chokes. SMD ferrites capable of high inrush currents are a reasonable addition.
Input/Output Capacitors
For lower ESR, aluminum polymer capacitors are recommended for bulk capacitors. Conventional electrolyt capacitors are suitable as well.
Input/Output Capacitors
For lower ESR, aluminum polymer capacitors are recommended for bulk capacitors. Conventional electrolyt capacitors are suitable as well.
Coupling Capacitor
During the off-time of the FET, the entire input current flows through the coupling capacitor. REDEXPERT gives you all the necessary information on temperature rise depending on AC ripple currents.
Common Mode Choke
Isolated SMPS are a main cause of common mode disturbances. For proper electromagnetic compatibility we suggest a Common Mode Choke as input filter.
RCD-Snubber
Snubber circuits protect against transient voltages that occur during turn-off and also have a positive impact on conducted Emissions.
Transformer with Air Gap
For the flyback topology the transformer has three functions: Transforming the voltage according to its turns ratio, Isolation between primary and secondary windings as well as short-term storage of energy during the off-cycle of the FET. Depending on your application, various winding configurations and mounting options are available.
Custom Solutions Possible
Our engineers are waiting to create a transformer that’s as unique as your application, with personalized details, and a range of options dialed in to exactly what you need.
Switch
A higher switching frequency will enable smaller Inductors and smaller filter components. However, radiated EMI might increase.
Schottky Diode
Diode‘s junction capacitance in combination with parasitic inductance of traces can lead to ringing.
Short Introduction to Flyback Converter
The flyback converter is an isolated topology of the buck-boost converter. Depending on the winding ratio of the coupled power inductor, the input voltage can be higher, lower or equal to the output voltage.
The isolated output feedback can be obtained directly from a transformer winding or via an optocoupler.
The flyback is a simple solution for an isolated switching power supply (SMPS) with low power output. For power ratings above 50 W other topologies are usually more efficient.
Reference Designs
RD001 6 W Bipolar isolated auxiliary supply for SiC-MOSFET and IGBT gate driver
RD002 6 W Unipolar isolated auxiliary supply for SiC-MOSFET and IGBT gate driver
Flyback Simulation in REDEXPERT
Determine the best suitable flyback transformer within seconds for discontinuous mode, boundary mode or quasi resonant mode.
