The Mazilli ZVS flyback driver is well-known throughout the high voltage community for its simplicity and ability to deliver 20-50 kV at high currents for a flyback transformer.
I build this circuit almost a year ago on a vero board, but it kept blowing the thin traces due to high currents flowing. I eventually put the project in a box and forgot all about it.
Inspired by the point to point soldered designs Myke from the 4hv.org forums often uses, I tried to make something in that manner, not as pretty as his work though.
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The MOSFETs used need a voltage rating about 4 times higher than the supply voltage and a on-resistance below 150 mΩ
5 + 5 primary windings are suitable for voltages between 10 to 40 VDC, at higher voltages additional windings will be needed. Experiment with the number of windings to improve performance. Too few windings will result in excessive heating and too many will result in reduced power output.
A MMC is made from 6 capacitors to avoid excessive heating in a single capacitor.
This driver will push as much power as it can, so be sure to use flyback transformers that can handle the abuse if you want it to live.
|Voltage supply||35 VDC from a rewound microwave oven transformer.|
|MMC||0.66 uF from series string of 3x 2 275VAC MKP X2 capacitors in parallel .|
|Power consumption||400 Watt.|
|Longest arc||100 – 110 mm long white arcs|
15th may 2009
I have now rebuild the driver using 2.5mm² / 14AWG wire for a good current ability, larger heat sinks and a MMC to avoid as much heating as possible.
16th may 2009
I found 4 different flyback transformers from my collection, among these are a 1980’s Bang & Ollufsen television flyback. A small flyback from a photocopier. A flyback from a 1990’s portable television, it is without screen and focus resistor networks. A flyback with rectifier tube from a black & white 1950’s television.
The pictures with long arcs about the size of 100 – 110 mm was made with the 1980’s Bang & Ollufsen flyback transformer.
It was well worth it to rebuild this driver. It can now handle long run times with little heating despite pushing out around 400 Watt of power!