Fly-Buck™ isolated DC/DC converters
Create an isolated supply by replacing your buck inductor with a transformer
Isolated DC/DC Fly-Buck™ converters simplify the task of generating isolated positive and negative supplies using only a small number of off-the-shelf external components. Unlike traditional flyback converters, this flexible topology does not need an opto-coupler, resulting in a smaller and more cost-optimized isolated solution.
Flyback-like isolation
Generate positive and/or negative isolated outputs
Multi-output
Add coupled windings to generate multiple isolated outputs
Simple design
A familiar synchronous buck converter base-architecture with common off-the-shelf components
Small solution size
High integration and very few external components
What is a Fly-Buck™ converter?
The Fly-Buck converter topology takes a common synchronous buck converter and adds coupled windings to the primary inductor to be transformed into a cost-effective solution for multiple, flyback-like isolated outputs (Vpri and Vsec in the diagram below). The transformer turns ratio determines the secondary output voltage, which closely tracks the primary output voltage and thus eliminates the need for an optocoupler or auxiliary winding.

Featured products
Featured design resources
Reference design for generating multiple isolated bias supplies from a nominal 24V input using a single LM5017 and a low-profile transformer.
See how easy it is to pair your Fly-Buck with an off-the-shelf coupled inductor from Coilcraft
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