Flyback Switch Mode Power Supply Circuit

This is a flyback SMPS that will boost voltage a voltage of around 20V to 40V, or more if you change the feedback resistors.  It uses an off the shelf transformer from CoilCraft. The LM3479 is a nice controller because it’s frequency of operation can be set by changing R1.  At 39K it runs at about 500KHz.  

 Flyback Switch Mode Power Supply Circuit

One innovation of the circuit is that the regulator is driven with +5V, a smaller voltage than VPIN.  Separating the regulator voltage supply from the supply driving the coil allows VPIN to be nearly any value.  Of course you need to have the 5V generated else where.  

The circuit also has a non-dissipative snubber circuit on the drain of the MOSFET, to limit the voltage spikes when the transistor turns off.

See our calculators to make modifications to the feedback circuit, or use a different transformer. 

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For more detail: Flyback Switch Mode Power Supply Circuit

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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