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 #1902
Joined: Fri Jan 02 2009, 07:59PM
Location: Lancaster, NY
Posts: 75
Hi all, I've been hard at work making my newest class-e SSTC. As usual I have some problem it's seems in order to tune it to class-e switching I have the decrease the coupling so much that it no longer breaks out(with coaxing). But when I do increase the coupling it runs happy with about 1-2mm of coaxed breakout. The weird thing is the mosfet runs as hot as when it's detuned for breakout, when I'm switching class-e. Here are the specs and pics!
Bus V: 12-18vdc Mosfet: IRF720 Freq: ~2.5Mhz (no topload) Driver: Antenna feedback via UCC driver chip (runs on 12vdc) Mosfet On Resistence: 1.9Ohms Gate Capacitence: .9nF or 900pF (Measured G-S)
Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
Is the current through the MOSFET near 0 when it switches? Sorry if it seems like I'm hijacking the thread but... I'm wondering if it is possible to get the voltage and current near 180 degrees out of phase for class E switching. It didn't seem very easy to get the current to behave properly in simulation. It seems like people mostly just check the voltage across the MOSFET which seems like it wouldn't guarantee the current falling near 0 to minimize dissipation. Why's that?
Registered Member #1232
Joined: Wed Jan 16 2008, 10:53PM
Location: Doon tha Toon!
Posts: 881
> The weird thing is the mosfet runs as hot as when it's detuned for breakout, when I'm switching class-e
Probably just on-state conduction losses. The IRF720 device has quite a high Rds(on) value. It is not really suited to a low voltage Class-E amp running from only 12V. It is much more suited to a high voltage Class-E amplifier running from something like 80 or 100VDC with much lower currents. Hence lower I²R losses during the on-time.
If you want to run it from only 12-18VDC I'd swap the switching MOSFET for something like the IRF540. It is a larger die device but you still shouldn't have any problem driving the gate at only 2.5MHz.
Registered Member #1902
Joined: Fri Jan 02 2009, 07:59PM
Location: Lancaster, NY
Posts: 75
So in reality upping the bus voltage and increasing primary turns to limit current would be better? Will this also solve my coupling issue? Sorry for so many questions it's just I've been working on shunt cap/primary inductance combos for the last two days and this is the best it's been so far. >.<
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.
Sissy Tess!
