Welcome
Username or Email:

Password:


Missing Code




[ ]
[ ]
Online
  • Guests: 27
  • Members: 0
  • Newest Member: omjtest
  • Most ever online: 396
    Guests: 396, Members: 0 on 12 Jan : 12:51
Members Birthdays:
One birthday today, congrats!
MicroTesla (34)


Next birthdays
07/09 Avi (41)
07/09 Jannick Hagen (15)
07/10 Sparcz (69)
Contact
If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.


Special Thanks To:
  • Aaron Holmes
  • Aaron Wheeler
  • Adam Horden
  • Alan Scrimgeour
  • Andre
  • Andrew Haynes
  • Anonymous000
  • asabase
  • Austin Weil
  • barney
  • Barry
  • Bert Hickman
  • Bill Kukowski
  • Blitzorn
  • Brandon Paradelas
  • Bruce Bowling
  • BubeeMike
  • Byong Park
  • Cesiumsponge
  • Chris F.
  • Chris Hooper
  • Corey Worthington
  • Derek Woodroffe
  • Dalus
  • Dan Strother
  • Daniel Davis
  • Daniel Uhrenholt
  • datasheetarchive
  • Dave Billington
  • Dave Marshall
  • David F.
  • Dennis Rogers
  • drelectrix
  • Dr. John Gudenas
  • Dr. Spark
  • E.TexasTesla
  • eastvoltresearch
  • Eirik Taylor
  • Erik Dyakov
  • Erlend^SE
  • Finn Hammer
  • Firebug24k
  • GalliumMan
  • Gary Peterson
  • George Slade
  • GhostNull
  • Gordon Mcknight
  • Graham Armitage
  • Grant
  • GreySoul
  • Henry H
  • IamSmooth
  • In memory of Leo Powning
  • Jacob Cash
  • James Howells
  • James Pawson
  • Jeff Greenfield
  • Jeff Thomas
  • Jesse Frost
  • Jim Mitchell
  • jlr134
  • Joe Mastroianni
  • John Forcina
  • John Oberg
  • John Willcutt
  • Jon Newcomb
  • klugesmith
  • Leslie Wright
  • Lutz Hoffman
  • Mads Barnkob
  • Martin King
  • Mats Karlsson
  • Matt Gibson
  • Matthew Guidry
  • mbd
  • Michael D'Angelo
  • Mikkel
  • mileswaldron
  • mister_rf
  • Neil Foster
  • Nick de Smith
  • Nick Soroka
  • nicklenorp
  • Nik
  • Norman Stanley
  • Patrick Coleman
  • Paul Brodie
  • Paul Jordan
  • Paul Montgomery
  • Ped
  • Peter Krogen
  • Peter Terren
  • PhilGood
  • Richard Feldman
  • Robert Bush
  • Royce Bailey
  • Scott Fusare
  • Scott Newman
  • smiffy
  • Stella
  • Steven Busic
  • Steve Conner
  • Steve Jones
  • Steve Ward
  • Sulaiman
  • Thomas Coyle
  • Thomas A. Wallace
  • Thomas W
  • Timo
  • Torch
  • Ulf Jonsson
  • vasil
  • Vaxian
  • vladi mazzilli
  • wastehl
  • Weston
  • William Kim
  • William N.
  • William Stehl
  • Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Forums
4hv.org :: Forums :: High Voltage
« Previous topic | Next topic »   

Improved single transistor flyback driver

Move Thread LAN_403
811a vttc
Sat Aug 14 2010, 05:29AM
811a vttc Registered Member #3097 Joined: Tue Aug 10 2010, 03:35PM
Location: Ontario Canada
Posts: 13
Um i just tested it on my flyback it oscillated but it killed my flyback angry

so i hooked it up to a micro sstc using a ferite core transformer to get the oscilations then i ran that into my sstc, it worked!amazed
Back to top
tritium
Mon Aug 23 2010, 03:54PM
tritium Registered Member #2591 Joined: Fri Jan 01 2010, 11:58AM
Location: netherlands
Posts: 76
Dr. Kilovolt wrote ...


The cap and the primary winding form a parallel resonant circuit and the driver starts to operate in "pseudo class E" mode, not exact Class E switching, but it improves performance greatly and decreases transistor heating (mainly because it has more time to turn off - Toff switching losses are minimised).


is this paralel resonance? the primary and cap are in serie.

I think it is serie resonance or do I understand something wrong?
Back to top
Dr. Dark Current
Mon Aug 23 2010, 03:58PM
Dr. Dark Current Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
its parallel resonance, it doesn't matter if you connect the resonant cap to the +V or GND rail, because they are AC coupled by the filter cap.
Back to top
tritium
Mon Aug 23 2010, 05:12PM
tritium Registered Member #2591 Joined: Fri Jan 01 2010, 11:58AM
Location: netherlands
Posts: 76
is it the same like this?

1282583502 2591 FT37658 Schema2
Back to top
Dr. Dark Current
Mon Aug 23 2010, 05:24PM
Dr. Dark Current Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
yes its the same, just I'd rather put the cap across the transistor because of wiring inductances which might result in some ringing (but probably of no significance).
Back to top
tritium
Mon Aug 23 2010, 06:21PM
tritium Registered Member #2591 Joined: Fri Jan 01 2010, 11:58AM
Location: netherlands
Posts: 76
I think we can run this circuit without high power resistors, if we know the Al of the core and also L of the feedback.

Maybe I don't understand everything, but I will just try to improve this circuit.

@dr kilovolt,
how did you calculate the resistor values?

Back to top
Dr. Dark Current
Mon Aug 23 2010, 07:12PM
Dr. Dark Current Registered Member #152 Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
tritium wrote ...

@dr kilovolt,
how did you calculate the resistor values
The bottom resistor sets the turn-off current (via the transistor's Hfe) and in turn output power. The upper resistor just needs to provide above 0.7V on the divider output, so the transistor doesn't stay turned off.

Ps. This circuit is a little outdated, now I would maybe do it a bit different, but have no time for testing the circuits right now.
Back to top
quicksilver
Mon Aug 23 2010, 10:58PM
quicksilver Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679
I've tweaked this circuit many times and that's what I've come to understand (the bottom resistor is turn-off current) However even 5w is a touch light in certain circumstances: do not go to anything lower than 5w; in fact it appears to preform w/ less stress on a TO-220 package if yo raise that to 10w. Using a MJ13009 x-sistor I got some fair performance with anything from a 18-24ohm.

I happen to like it because it's so "flexible". I beefed up all components and it handled quite a bit of power. I have compared differing caps and gotten great results with higher (than 4700uf) capacitance (& voltage). It's a far cry from a ZVS but for it's potential size; it's a lot of fun.

I HAVE tried putting a cap across the x-sister & I like it better.
The fact that you can make it SO small that the only real room is taken by the heat-sink makes it fun to put in a small box w/ the flyback.
Back to top
tritium
Sat Aug 28 2010, 05:43PM
tritium Registered Member #2591 Joined: Fri Jan 01 2010, 11:58AM
Location: netherlands
Posts: 76
@dr. kilovolt
are you willing to post your new design?
Back to top
Alex M
Tue Jul 05 2011, 10:10PM
Alex M Registered Member #3943 Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552
I am going to give this a try but have one question, is the 4700uF cap across the power supply essential as I am using a 12 7AH lead acid battery for my supply (which works fine for the regular 2n3055 version, giving 1 1/2 inch arcs from one of my flybacks!). Or is it only needed when using a power supply where ripple current might be an issue?

Thanks.
Back to top

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

Go to:

Powered by e107 Forum System
 
Legal Information
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.