Full bridge flyback transformer driver / High Voltage / Forums

Forums

4hv.org :: Forums :: High Voltage

« Previous topic | Next topic »

Full bridge flyback transformer driver

1 2 3 next

Move Thread

LAN_403

Daedronus

Tue Nov 22 2011, 10:18PM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

If there is one reason I decided to post this here is because of all the threads about ZVS this, ZVS that.
I don't like the ZVS driver, doesn't scale well and is hard to control it.

This is a example of what a full bridge can do.

The input voltage is about 70V and 7-8A.
4 IRFP360 are used.

ifryd

Tue Nov 22 2011, 10:29PM

Registered Member #4215 Joined: Wed Nov 16 2011, 09:45PM
Location:
Posts: 32

Did you build this converter? Do you have schema or link to the website where I could look at it?

Marko

Tue Nov 22 2011, 10:56PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Hi daedronius

Funny, I googled "SG3525 flyback driver" and the first result in pictures was my own schematic from long ago:

I always recommended this to anyone who wishes to put arbitrary amounts of power into a flyback but everyone just keeps crying and doing their way.

The only problem is that it's quite hard to control yourself once you have something like this, and the reality is most ordinary flybacks will die before reaching half of the arc length daedronius had in this video from his monster flyback.

Marko

PS. not written on the schematic, the flyback primary is 30-50 turns of thickest possible wire wound on the outer leg of the core.

Ofcourse this circuit can work of 120V mains too (with suitable mosfets like IRFP250's) and can also use TL494 IC with some bjt totem poles for output amplification.

Oh, did I say it works with ignition coils too? (they are far more punishment resistant than flybacks)

Daedronus

Tue Nov 22 2011, 11:38PM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

The internal diode in that flyback was already killed in this video. It outputs AC instead of the normal (doubled?) DC.

The bridge itself is meant for other purposes but it was too fun not to hook it up to a flyback.

I have another video where the same bridge drives a self made secondary with much less turns in the secondary, the output voltage is far less impressive but the damage done to the electrodes is.

Kiwihvguy

Wed Nov 23 2011, 08:06AM

Registered Member #3395 Joined: Thu Nov 04 2010, 08:42AM
Location: Christchurch, New Zealand
Posts: 193

WOW! Awesome arcs dude, I am so jealous! Your flyback must have got pretty hot during those insane arcs. Careful, it looks like the flybacks HV lead is corona-arcing to your screwdriver...

Other than that, great job! Can I ask what camera you used? Nice quality.

Daedronus

Wed Nov 23 2011, 09:51AM

Registered Member #2329 Joined: Tue Sept 01 2009, 08:25AM
Location:
Posts: 370

Actually, everything was quite cold

And yes, when you see that corona arcing I got a bit of a sock.

I always try to use the one hand rule when dealing with this kind of things, my other hand is always behind my back so even if I get a sock is not across my chest/heart.

The camera is a canon 500d dslr

Alex M

Wed Dec 07 2011, 06:55PM

Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552

Which version of the SG3525 did you use? Is there difference in using SG3525AN and SG3525ANG?

Inducktion

Wed Dec 07 2011, 07:07PM

Registered Member #3637 Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068

AS far as I'm aware, as long as they maintain the main part number, you can use any variety of 3525.

KA3525, SG3525, SG3525ANG, SG3525AN, whatever, they'll all work.

Alex M

Wed Dec 07 2011, 07:10PM

Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552

It is just I have found that the SG3525ANG can supply 400mA current and outputs 19v. I only noticed this after I ordered SG3525AN which can output 5v @ 100mA and had a "Oh sh*t" moment.

Marko

Wed Dec 07 2011, 07:38PM

Registered Member #89 Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145

Alex1M6 wrote ...

It is just I have found that the SG3525ANG can supply 400mA current and outputs 19v. I only noticed this after I ordered SG3525AN which can output 5v @ 100mA and had a "Oh sh*t" moment.

I don't understand your problem, all SG3525's can stand supply voltages up to about 35V and they can drive smaller mosfets like IRFP450's directly too without problem. the 5V 100mA rating is for the voltage reference supply.

For larger devices you could double your supply voltage and use a step-down gdt to increase the drive current. Or use bipolar totem pole amplifiers if you're driving something really big :)

Marko

1 2 3 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob