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 #816
Joined: Sun Jun 03 2007, 07:29PM
Location:
Posts: 156
I apologize if I did not explain things very well in my earlier posts and added to the confusion.
What is the problem your describing now? Have you worked your way through it using a scope? You should be able to see if the voltages are in the right range, and see the current transformer output. If you look at the block diagram for the ic, and try to imagine what would be happening when the signals you measured are present on the pins.
Admittedly the difference between getting something to just work, and then make it stable so it regulates well can be tricky.
Registered Member #11591
Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556
If you look on page 10 of the datasheet, you will see that pin 6 should be connected directly to pin 7 in voltage mode operation, no RC network required! Pin 9 is the OC shutdown and should be grounded if it isn't being used.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Electra wrote ...
I apologize if I did not explain things very well in my earlier posts and added to the confusion.
no that's not it, you've helped.
Electra wrote ...
What is the problem your describing now? Have you worked your way through it using a scope? You should be able to see if the voltages are in the right range, and see the current transformer output. If you look at the block diagram for the ic, and try to imagine what would be happening when the signals you measured are present on the pins.
I get only the triangle wave out of Ct. no other parts seem to work. id like to skip the current transformer for now. At this point id be happy just to get any PWM at all out of pins 11 and 14.
hen918 wrote ...
If you look on page 10 of the datasheet, you will see that pin 6 should be connected directly to pin 7 in voltage mode operation, no RC network required! Pin 9 is the OC shutdown and should be grounded if it isn't being used.
I have done this, but ill ground pin 9 to see what changes.
Registered Member #11591
Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556
It is a fresh IC isn't it? I mean you haven't blown the output transistors from a previous set-up? Also, are you using it isolated or non-isolated? That determines what you do with pins 1 and 2.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
hen918 wrote ...
It is a fresh IC isn't it? I mean you haven't blown the output transistors from a previous set-up? Also, are you using it isolated or non-isolated? That determines what you do with pins 1 and 2.
yes its a new IC. I'm wanting to use it non-isolated. Id like to spoof the input at 1 and 2. its just so frustrating that I don't get any PWM at all.
EDIT: I'm going to start with a 555 timer just to stay on track, but ive got to get this circuit working.
EDIT:
I'm getting a bizarre and unacceptable signal across the GND and V+ !
Let me see if a new cap and the UVLO is the problem . . .
EDIT: the above scope shot is due to the 11.8 Vdc power supply, let me switch over to a linear one. I'm so far behind schedule.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
I *may* have had an issue with soldering the right IC on the board. it appears to be the UC28023 . . . . [ face palm ]
I did get the wrong version (UC28023) version, to get its single output to stay high, after making some changes you guys have suggested. so I'm trying to get the right IC soldered in. EDIT: I am getting a PWM now, it appears to be 50%, one of my Oscope probes seems to be not working, but both outputs do oscillate, but without the 2 probes I cant be sure there opposing each other. though I suspect they do.
I think the above waveform has about 200nS of dead time. from figure 8 and 10.
Registered Member #11591
Joined: Wed Mar 20 2013, 08:20PM
Location: UK
Posts: 556
It's difficult to tell the dead time from your latest 'scope shot because it's only running at 1MS/s this means that with the frequency at 33kHz, the scope is only sampling 30 times in every cycle, that's probably why the slew looks so high. Dropping the timebase should force the 'scope to use a higher sample rate, if it can.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
hen918 wrote ...
It's difficult to tell the dead time from your latest 'scope shot because it's only running at 1MS/s this means that with the frequency at 33kHz, the scope is only sampling 30 times in every cycle, that's probably why the slew looks so high. Dropping the timebase should force the 'scope to use a higher sample rate, if it can.
it cant, its crap, but its the best ive got. Id like to put in a potentiometer to send a spoof signal into the feedback circuit. then watch the PWM change in real time on the scope.
EDIT : heres the voltage divider that backed the PWM off quite abit.
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.