I need to make a high voltage (2-6 kV), high frequency (20-50 kHz) power supply in order to generate cold plasma (in Ar gas). I use a fly back circuit (found in web) could allow me to to that. The high frequency will be generate by the self oscillating fly back transformer.

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I made a transformer myself, with 3000 turns on the secondary and (4+4) on the primary and everything works. Input is 12V and I could get ~ 5 kV output at 10-30 kHz. But there is a problem that the oscillating frequency only depends on the feritte core and the number of turns in the flyback transformer (e.g.: 4+4 or 5+5), therefore it is difficult to control.

I have few questions:

(1) Can I achieve my goal with an IC use to generate the high frequency pulse and feed it to my transformer? That way, I can control the oscillating frequency well.

(2) I found a circuit online use IC555, but it is for car ignition. Will it work in my case? If not, what I need to change in the circuit?

enter image description here (3) I realize that flyback transformer was used much more common that an IC controlled one (like in an plasma ball). Why is it? Is it more efficient?

Many thanks for any advice/suggestion!

  • \$\begingroup\$ 1. Not only can, you should! 2. You need to modify several things, rectification and smoothing on the output and a mean for regulation. Save yourself the trouble and get yourself a proper flyback IC. 3. Regulation and overcurrent protection to name a few. Stay away from 555. \$\endgroup\$ – winny Apr 6 '18 at 5:48
  • \$\begingroup\$ Thanks for the response. I have little experience in IC circuit. Could you please give more detail what exactly and how should I change in the circuit (2) to achieve my goal. And which IC should I use to generate the oscilating frequency (20-50Khz)? Thanks alot. \$\endgroup\$ – Anlong Apr 6 '18 at 9:48
  • \$\begingroup\$ UCC28740 springs to mind, but there are literally hundreds of others to choose from. \$\endgroup\$ – winny Apr 7 '18 at 8:46

Do not use flyback topology here, because the reflected voltage will damage your SWITCH.

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  • \$\begingroup\$ Thank you. Are you mentioning circuit (1) or (2)? For circuit (1), everything works and I could run for 10 minutes continuously without anything damage. For circuit (2) it is not a flyback transformer. \$\endgroup\$ – Anlong Apr 6 '18 at 4:08
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    \$\begingroup\$ Why would it? -1 \$\endgroup\$ – winny Apr 6 '18 at 5:44

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