Steve's Mini SSTC, again.
Munkey, Wed Sept 26 2007, 06:35PMI suppose you are thinking not another topic on this!
So after failing to design my own SSTC, I though I would make the very popular Steve's mini SSTC I have seen people make that successfully, but I have questions...
Even before I have even made it I have blown up 4 of my 5 UCC chips just by "testing" them. And I am saving the last one for the actual one when I get enough money to by the diodes and FETs (of "...") Anyway, I wondered if I could make the UCC chip drive some BD139 and BD140 in a full bridge (I will post schematic later) to hopefully make them last more than a few seconds in my hands! Will that work?
And would it work with a 1uF tank cap? Would I have to change the primary windings?
My secondary is long and skinny, it has just over 1300 windings over a 2inch cardboard former, will I have to change the primary/tank cap to make it work?
Thanks!
Re: Steve's Mini SSTC, again.
Zum Beispiel, Wed Sept 26 2007, 06:43PM
A quick search on datasheetarchive.com tells me that BD140 and 139 are PNP and NPN transistors... These will need a completely different driver than the regular UCC+GDT combo.
You need N-channel mosfets for this job (the GDT gives isolated drive to the upper fet(s)).
And what tank cap? It's a regular non-resonant primary SSTC, so there is no tank cap.
Do you mean the DC blocking cap on GDT primary? or the caps accross the bridge supply rails?
In either case 1µF should be fine.
Zum Beispiel, Wed Sept 26 2007, 06:43PM
A quick search on datasheetarchive.com tells me that BD140 and 139 are PNP and NPN transistors... These will need a completely different driver than the regular UCC+GDT combo.
You need N-channel mosfets for this job (the GDT gives isolated drive to the upper fet(s)).
And what tank cap? It's a regular non-resonant primary SSTC, so there is no tank cap.
Do you mean the DC blocking cap on GDT primary? or the caps accross the bridge supply rails?
In either case 1µF should be fine.
Re: Steve's Mini SSTC, again.
Munkey, Wed Sept 26 2007, 07:29PM
I think it is called a tank cap, its the 0.68uF ones on this schematic:
And the different secondary shouldn't really matter...
Munkey, Wed Sept 26 2007, 07:29PM
Zb wrote ...
A quick search on datasheetarchive.com tells me that BD140 and 139 are PNP and NPN transistors... These will need a completely different driver than the regular UCC+GDT combo.
All the UCCs do Is make a full-bridge, right? So I am extending the current capability by making it drive bigger transistors and making it more robust, hopefully making it harder to kill. I think... Heres the schematic: A quick search on datasheetarchive.com tells me that BD140 and 139 are PNP and NPN transistors... These will need a completely different driver than the regular UCC+GDT combo.
Zb wrote ...
You need N-channel mosfets for this job (the GDT gives isolated drive to the upper fet(s)).
I'm confused...You need N-channel mosfets for this job (the GDT gives isolated drive to the upper fet(s)).
Zb wrote ...
And what tank cap? It's a regular non-resonant primary SSTC, so there is no tank cap.
Do you mean the DC blocking cap on GDT primary? or the caps across the bridge supply rails?
In either case 1µF should be fine.
And what tank cap? It's a regular non-resonant primary SSTC, so there is no tank cap.
Do you mean the DC blocking cap on GDT primary? or the caps across the bridge supply rails?
In either case 1µF should be fine.
I think it is called a tank cap, its the 0.68uF ones on this schematic:
And the different secondary shouldn't really matter...
Re: Steve's Mini SSTC, again.
Zum Beispiel, Wed Sept 26 2007, 07:56PM
Oh, sorry. I though you meant to use the BD140s and 139s in your bridge, my bad.
Yeah, I guess you can use transistors to boost the UCCs output power, but I think it is easier just to parallel a few drivers if you need more power. Atleast I imagine this would be more trouble free.
Do you know what killed your UCCs? I've found them to be pretty hard to kill. Do they heat up? Try adding more turns to your GDT and using a different size DC-blocking cap. Also, these things need a lot of decoupling. I used a 100nF poly, 10µF tant and a 470µF electrolytic on my UCCs in my bigger SSTC.
Oh, and the secondary size won't matter. The driver is self tuning, after all.
Zum Beispiel, Wed Sept 26 2007, 07:56PM
Oh, sorry. I though you meant to use the BD140s and 139s in your bridge, my bad.
Yeah, I guess you can use transistors to boost the UCCs output power, but I think it is easier just to parallel a few drivers if you need more power. Atleast I imagine this would be more trouble free.
Do you know what killed your UCCs? I've found them to be pretty hard to kill. Do they heat up? Try adding more turns to your GDT and using a different size DC-blocking cap. Also, these things need a lot of decoupling. I used a 100nF poly, 10µF tant and a 470µF electrolytic on my UCCs in my bigger SSTC.
Oh, and the secondary size won't matter. The driver is self tuning, after all.
Re: Steve's Mini SSTC, again.
Munkey, Wed Sept 26 2007, 08:09PM
Ok I am going to keep it short. I over-volted them all when they were in the breadborad stage. I made the driver (but without the GDT and half-bridge because I didn't and still don't have the parts) to drive a FET for a flyback driver, and each time for some stupid reason I managed to turn the voltage control knob on my PSU right up frying them. FOUR TIMES IN A ROW. I am the walking curse
Would the primary size matter?
Munkey, Wed Sept 26 2007, 08:09PM
Zb wrote ...
Oh, sorry. I though you meant to use the BD140s and 139s in your bridge, my bad.
Yeah, I guess you can use transistors to boost the UCCs output power, but I think it is easier just to parallel a few drivers if you need more power. Atleast I imagine this would be more trouble free.
If I could get them for cheap I would Oh, sorry. I though you meant to use the BD140s and 139s in your bridge, my bad.
Yeah, I guess you can use transistors to boost the UCCs output power, but I think it is easier just to parallel a few drivers if you need more power. Atleast I imagine this would be more trouble free.
Zb wrote ...
Do you know what killed your UCCs? I've found them to be pretty hard to kill. Do they heat up? Try adding more turns to your GDT and using a different size DC-blocking cap.
Do you know what killed your UCCs? I've found them to be pretty hard to kill. Do they heat up? Try adding more turns to your GDT and using a different size DC-blocking cap.
Ok I am going to keep it short. I over-volted them all when they were in the breadborad stage. I made the driver (but without the GDT and half-bridge because I didn't and still don't have the parts) to drive a FET for a flyback driver, and each time for some stupid reason I managed to turn the voltage control knob on my PSU right up frying them. FOUR TIMES IN A ROW. I am the walking curse
Would the primary size matter?
Re: Steve's Mini SSTC, again.
Ken M., Wed Sept 26 2007, 09:29PM
Just use 10 turns.
Ken M., Wed Sept 26 2007, 09:29PM
Just use 10 turns.
Re: Steve's Mini SSTC, again.
Steve Conner, Thu Sept 27 2007, 09:06AM
UCCs have plenty of power, they shouldn't need boosted. If you're killing them, you're just doing something wrong, and you need to figure out what and fix it, instead of adding bits to the circuit.
Steve Conner, Thu Sept 27 2007, 09:06AM
UCCs have plenty of power, they shouldn't need boosted. If you're killing them, you're just doing something wrong, and you need to figure out what and fix it, instead of adding bits to the circuit.
Re: Steve's Mini SSTC, again.
Munkey, Thu Sept 27 2007, 02:59PM
^ I when I killed them I wasn't using them in the SSTC schematic. I was just fiddling with them on the breadboard making them drive fets for a flyback. For some stupid reason I would over-volt them, like my hand slipped and hit the voltage control knob on my PSU thats powering it, that happened three times. Or I connect the breadboard up when the voltage is set to full (twice) of coarse blowing them. Or putting a voltage regulator in backwards and feeding it 40V Fireworks! Fun, Fun, Fun. NOT.
And I just blew up my last one when trying to make this: circuit. powered it on 24V... nothing (there was an output though), powered it on 32V CRACK! the top of my last UCC chip blew open. im F***ing pissed of now. I try, I fail, why bother trying?
I can't beleve a little SO-8 SMD chip can provide so much power, they don't even have a little heat-spreader on the bottom...
Munkey, Thu Sept 27 2007, 02:59PM
^ I when I killed them I wasn't using them in the SSTC schematic. I was just fiddling with them on the breadboard making them drive fets for a flyback. For some stupid reason I would over-volt them, like my hand slipped and hit the voltage control knob on my PSU thats powering it, that happened three times. Or I connect the breadboard up when the voltage is set to full (twice) of coarse blowing them. Or putting a voltage regulator in backwards and feeding it 40V Fireworks! Fun, Fun, Fun. NOT.
And I just blew up my last one when trying to make this:
circuit. powered it on 24V... nothing (there was an output though), powered it on 32V CRACK! the top of my last UCC chip blew open. im F***ing pissed of now. I try, I fail, why bother trying?I can't beleve a little SO-8 SMD chip can provide so much power, they don't even have a little heat-spreader on the bottom...
Re: Steve's Mini SSTC, again.
Steve Conner, Fri Sept 28 2007, 08:53AM
I guess you hadn't RTFDS and you didn't know that the maximum supply voltage UCC's are rated for is 15V?
Steve Conner, Fri Sept 28 2007, 08:53AM
I guess you hadn't RTFDS and you didn't know that the maximum supply voltage UCC's are rated for is 15V?
Re: Steve's Mini SSTC, again.
Dr. H., Fri Sept 28 2007, 11:11AM
If you look closely to the circuit you will see that the UCC is feeded with 12v instead of the full voltage.
Dr. H., Fri Sept 28 2007, 11:11AM
If you look closely to the circuit you will see that the UCC is feeded with 12v instead of the full voltage.
Re: Steve's Mini SSTC, again.
Munkey, Fri Sept 28 2007, 02:39PM
Yes I know the max working voltage is 15. I stuck a 5V reg in for the ucc and the 555. the coil was powered on 32V
Do any of you guys know how to make a indestructible FET driver like the ucc?
Munkey, Fri Sept 28 2007, 02:39PM
Steve Conner wrote ...
I guess you hadn't RTFDS
Excuse my stupidity but what is RTFDS?I guess you hadn't RTFDS
Yes I know the max working voltage is 15. I stuck a 5V reg in for the ucc and the 555. the coil was powered on 32V
Do any of you guys know how to make a indestructible FET driver like the ucc?
Re: Steve's Mini SSTC, again.
Zum Beispiel, Fri Sept 28 2007, 02:59PM
Zum Beispiel, Fri Sept 28 2007, 02:59PM
Bacon wrote ...
Excuse my stupidity but what is RTFDS?
I believe it's a variation of RTFM.Excuse my stupidity but what is RTFDS?
Bacon wrote ...
Yes I know the max working voltage is 15. I stuck a 5V reg in for the ucc and the 555. the coil was powered on 32V
If you supply the UCCs with only 5V the voltage you are driving your FETs with will also be only 5V. This way they are in their linear region, causing massive dissipation in the FETs and killing them (unless they are "logic-level" FETs, that are fully turned on at around 5V).Yes I know the max working voltage is 15. I stuck a 5V reg in for the ucc and the 555. the coil was powered on 32V
Bacon wrote ...
Do any of you guys know how to make a indestructible FET driver like the ucc?
There are drivers made from discrete components floating around the net. These are pretty indestructible and powerfull, but serious overkill for this job. Besides, UCCs are pretty much bomb-proof, as long as you give them the right supply voltage, use generous amounts of decoupling and make sure your GDT is working properly (not saturating, proper material, DC-blocking etc).Do any of you guys know how to make a indestructible FET driver like the ucc?
Re: Steve's Mini SSTC, again.
Munkey, Fri Sept 28 2007, 03:45PM
Well the FET was fine, it was the ucc that decided to blow its top (literally) This time I did not overvolt it and it still died, it was only connected to a small BUK455 FET, this was my attempt at this circuit. The reason I did not power it on 12V is because when I did the oscillation stopped and the ucc got HOT.
I am going to try to build (and fail) an about 10 amp ucc equivalent...
for the GDT I used a ring of unknown material pulled out of a computer PSU.
I look like a real idiot saying what does RTFM mean. Jumping to concludtions by any chance?
Munkey, Fri Sept 28 2007, 03:45PM
Well the FET was fine, it was the ucc that decided to blow its top (literally) This time I did not overvolt it and it still died, it was only connected to a small BUK455 FET, this was my attempt at this
circuit. The reason I did not power it on 12V is because when I did the oscillation stopped and the ucc got HOT.I am going to try to build (and fail) an about 10 amp ucc equivalent...
for the GDT I used a ring of unknown material pulled out of a computer PSU.
I look like a real idiot saying what does RTFM mean. Jumping to concludtions by any chance?
Re: Steve's Mini SSTC, again.
..., Fri Sept 28 2007, 04:01PM
You didn't use the yellow powdered iron core out of the supply, did you?
You need ferrite (grey) cores.
..., Fri Sept 28 2007, 04:01PM
You didn't use the yellow powdered iron core out of the supply, did you?
You need ferrite (grey) cores.
Re: Steve's Mini SSTC, again.
Munkey, Fri Sept 28 2007, 05:35PM
Ugh, now I have got to buy one,
Screw that, I am going try to make this one, 5" sparks! Thats WAY enough to satisfy me. I would be over the moon if that works (I highly doubt that though) What is the value of the tank cap (C6) across the FET and YES I HAVE RTFM!
Munkey, Fri Sept 28 2007, 05:35PM
... wrote ...
You didn't use the yellow powdered iron core out of the supply, did you?
Yep it is a yellow one. Why is it bad to use them?You didn't use the yellow powdered iron core out of the supply, did you?
Ugh, now I have got to buy one,
Screw that, I am going try to make this
one, 5" sparks! Thats WAY enough to satisfy me. I would be over the moon if that works (I highly doubt that though) What is the value of the tank cap (C6) across the FET and YES I HAVE RTFM!Re: Steve's Mini SSTC, again.
Marko, Fri Sept 28 2007, 06:51PM
Because of way too low permeability and massive magnetizing current which blows the UCC's.
I't's material #26 powdered iron, you need ferrite, 77 or similar.
Also check if you didn't blow the regulator and it feeds full supply voltage to UCC. Be careful around those things..
Marko
Marko, Fri Sept 28 2007, 06:51PM
Why is it bad to use them?
Because of way too low permeability and massive magnetizing current which blows the UCC's.
I't's material #26 powdered iron, you need ferrite, 77 or similar.
Also check if you didn't blow the regulator and it feeds full supply voltage to UCC. Be careful around those things..
Marko
Re: Steve's Mini SSTC, again.
Munkey, Fri Sept 28 2007, 07:09PM
Here is my attempt at making a tougher equivalent to the UCC: Which parts are wrong/will it not work?
Munkey, Fri Sept 28 2007, 07:09PM
Marko wrote ...
Because of way too low permeability and massive magnetizing current
I know next to noting about transformers and magnetics, but do you mean the magnetic field is not "absorbed"?Because of way too low permeability and massive magnetizing current
Here is my attempt at making a tougher equivalent to the UCC:
Which parts are wrong/will it not work?Re: Steve's Mini SSTC, again.
Steve Conner, Sat Sept 29 2007, 07:50PM
BTW, it stands for Read The F***ing Data Sheet
The only times I have ever blown UCCs, were when the regulator failed and hit them with 30V, or if the magnetizing current (that Marko mentioned) got too high and made them latch up.
Steve Conner, Sat Sept 29 2007, 07:50PM
BTW, it stands for Read The F***ing Data Sheet
The only times I have ever blown UCCs, were when the regulator failed and hit them with 30V, or if the magnetizing current (that Marko mentioned) got too high and made them latch up.
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