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.
Registered Member #63
Joined: Thu Feb 09 2006, 06:18AM
Location:
Posts: 1425
The power going through the anticoil would be disproportionate (to its size) considering the small amount of power I can currently monger with any of my drivers.
On the other hand, for extra geek points I'm raising the fres on the UOMFGSTFUHFSSTC to 12MHz and redesigning the driver starting tomorrow. When he comes to real fruition (as opposed to single-figure-wattage discharges in a lightbulb), I'll start a thread.
And yes, the name is immature, and you guys better choose something else for it. =)
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
I was a bit busy this days so assembly of main board turned a bit slowish. :/
Here is a simplified plan of entire coil (pic = 1000 words). Just to add, electronics are supplied from polarity inverse to input voltage due to buck/boost. LM2575 shuts the circuit down once heatsink reaches critical temperature.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
If your regulator is giving a negative output, you're going to have trouble driving the gate of the main FET directly, since it needs a positive voltage. Put a minus sign in front of the "15V" label on your "9A Gate Driver" block and think about what's going to happen.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Ohh, I thought you were driving the logic off the same battery or whatever, as the drain supply to the Class-E power amp. My mistake. If you're not doing that though, why do you need the fancy buck-boost regulator at all? Can't you just use an auxiliary supply that gives more voltage?
BTW, I got this from Richie Burnett, I guess he's been reading our ponderings on what the RF chokes are for. Thanks Richie! :P
richie wrote ...
Incidentally, the reason why you should use an RFC, normally in the drain lead of a Class-E amp is because it acts like a constant current source and presents a high impedance to all the harmonics from the MOSFET switching. In short, it keeps RF current out of the supply wiring. In a Class E SSTC you could connect the TC primary in place of the RFC and it does work, but its inductance value will be much smaller than the RFC that you would otherwise have used to supply the drain. This means that there will be a larger ripple current through this component acting as the drain choke, plus the actual AC load current which flows through this inductor and the supply wiring!
The drain choke is normally thought of as a constant supply of current because it is sized to be large compared to the operating frequency. Since it is large the current through the RFC doesn't change significantly during one RF cycle. This constant current is then alternately redirected between the MOSFET channel and the load network of the Class-E amp as the device switches. In the interest of not quickly re-directing large currents over large paths, it makes sense to connect the load network of the Class-E amplifier directly across the switch. I.e. Drain-to-source across the MOSFET. Then the choke current can alternate between the MOSFET channel and the load network without having to take a detour around the PSU wiring and decoupling!
I guess the practical upshot of this, is that if you decide to use your primary coil in place of the RFC, you should bring the other end of the primary coil (that isn't connected to the drain) back close to the MOSFET source terminal, and connect it to the source via the best RF bypass capacitor you can get, making sure it has short leads. Then feed in the DC power across this cap. Even so, it'll probably still barf more RF back into the power supply wires than if you did it Richie's way.
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
The thing is fully functional finally. Board is ready to fit into it's place..
Driving a IRFP450 (2,5nF) at 2Mhz, gate signal 500ns 5V div. I took special care for a low inductance design and I get almost datasheet-like rise and fall times with 1 ohm gate resistor. UCC gets pretty hot with this. SMD resistor does good job keeping inductance low..
Under-board.
And yeah, I didn't forget to make space for power supply..
FOr higher power levels I may add forced air cooling to small heatsink..
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
I assembled the coil and did some preliminary tests; 2cm sparks at 12V, nothing impressive, and PLL seems to be somehow unlocky. I think I really need bigger VCO cap and a bit bigger DC blocking cap at CT, I think it is being overloaded and CT current is very low at low input voltages.
I know spark looks awful, I have always had trouble with that. I would need to shoot in dark and focus poorly on the rest of coil :/ If I underexpose sparks look few times shorter than really.
This run is at about 20V, som 4cm sparks. I didn't check it for class E yet but I used the same cap from before, primary and coupling are also close enough.
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
Coil got a new secondary and fancy hovering primary; I'm currently happy with it as is. Power supply will be added but I don't want to press with it.
This is how I blew my old secondary: after playng with various spark effects, vortexes and trans-dimensional portals I finally tangled a wire just in the middle of the secondary, shorting a lot of turns and setitng the thing of fire.
As he was ruin anyway I decided to make a new one, and this time without bad connections and bugs. With nicer, bigger topload it works flawlessly, somewhere above 1Mhz.
I don't aim for extreme frequencies yet as people still find large sparks more amusing than fact that coil works at 30Mhz or etc.
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.
Class E SSTC thread
But beginning of school somehow gave my will back.
