| Author |
Message |
Watson A.Name - \"Watt Su
Guest
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 Posted:
Tue Mar 22, 2005 8:08 pm Post subject:
Re: Toroid Core for LED V Boost |
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"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:7IL%d.236$FN4.218@newssvr21.news.prodigy.com...
| Quote: | Hello Michael,
My latest booster design uses one of the rough-surface toroids
(above) and the
20# wire. I put a new AA in it at 3:30 PM on Friday afternoon and
it's still
running as I write this (12:21 PM), nearly 45 hours. The All
Electronics bright
white LED is dim now compared to its dazzling self when the battery
was fresh,
but the light is sufficient that it could be used for close-in (12"
or so)
work. Transistor is a "wimpy 2N3904". 1K base resistor.
Sometimes a few hundred pF across that 1k can drive the base for a
snappier switching and a few more percent in efficiency. But you'd
have
to calculate that for the 2N3904.
|
For the ones I've built, I've used anywhere fron 1 to 3.3nF, and the
brightness goes up and total current goes down. So a few hundred pf may
not be enough. But it depends on the freq.
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Tim Williams
Guest
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| Posted:
Tue Mar 22, 2005 11:53 pm Post subject:
Re: Toroid Core for LED V Boost |
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"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:113vkq81dj1ui7a@corp.supernews.com...
| Quote: | Cattle prod. Electric fence shocker. Neon light blinky supply.
Think up some more uses.
|
Jim Thompson prod, to keep him from posting OT threads. ;-)
Tim
--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms |
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Jim Thompson
Guest
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| Posted:
Wed Mar 23, 2005 12:20 am Post subject:
Re: Toroid Core for LED V Boost |
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On Tue, 22 Mar 2005 11:53:57 -0600, "Tim Williams"
<tmoranwms@charter.net> wrote:
| Quote: | "Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:113vkq81dj1ui7a@corp.supernews.com...
Cattle prod. Electric fence shocker. Neon light blinky supply.
Think up some more uses.
Jim Thompson prod, to keep him from posting OT threads. ;-)
Tim
|
Too bad you really don't know how to design one.
Fookin' amateurs ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
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Rich Grise
Guest
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| Posted:
Wed Mar 23, 2005 1:31 am Post subject:
Re: Toroid Core for LED V Boost |
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On Mon, 21 Mar 2005 21:18:42 -0500, John Popelish wrote:
| Quote: | Joerg wrote:
(snip)
The switchers I designed with non-gapped
toroids ran efficiently. The normal losses were all accounted for, such
as those in the transistor, the diode, the ESR etc. but pretty much none
in the inductor. No ringing, nice linear ramps and the cores didn't get
hot. Mostly Fair-Rite stuff.
Do you remember what ferrite type you used? I agree that adding gaps
increases the volume of copper needed to keep the copper losses
unchanged, but ungapped boost designs tend to use a lot of ferrite
relative to the energy being transferred. For very low power designs,
this may not be very important.
|
But the gap makes it SO much easier to wind the toroid! ;-)
Cheers!
Rich |
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Joerg
Guest
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| Posted:
Wed Mar 23, 2005 3:50 am Post subject:
Re: Toroid Core for LED V Boost |
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Hello Watson,
| Quote: | IMHO, if it really was important, one would see these gaps in ferrite
toroids. But one doesn't.. (At least not in my experience.)
|
There are toroids where the ferrite is encapsulated in other stuff,
which essentially forms "micro gaps". But it can get expensive here.
Regards, Joerg
http://www.analogconsultants.com |
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Joerg
Guest
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| Posted:
Wed Mar 23, 2005 3:57 am Post subject:
Re: Toroid Core for LED V Boost |
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Hello Watson,
| Quote: | What I would really like to know is what were the parameters for the
.19" (ID) cores that All Electronics sold, ...
|
No big deal. Wind a few turns and measure the inductance. Now you have
the AL value. Hop in frequency so you can see where the core rolls off.
Then place a seconds winding on it and use the first winding again to
measure inductance. Run increasing DC through the second winding and see
when the inductance drops. Now you also know where it starts to saturate.
That's usually all you need to know. Of course, you could make resonant
circuits and find out losses and other stuff if you really wanted to know.
Regards, Joerg
http://www.analogconsultants.com |
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Watson A.Name - \"Watt Su
Guest
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| Posted:
Wed Mar 23, 2005 6:10 am Post subject:
Re: Toroid Core for LED V Boost |
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"QuantSuff" <uce@nospam.ftc.gov> wrote in message
news:1111498713.4e7698a737b9d77bc8a57f9b0e2a2094@teranews...
| Quote: |
"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:113vfmod40vn3a@corp.supernews.com...
(snip)
What I would really like to know is what were the parameters for the
.19" (ID) cores that All Electronics sold, but which are now out of
stock. I think someone said they were charcoal colored. It would
be
informative is someone with a bunch of them wound ten turns of, say,
24
gauge wire on a few and measured the inductance, so we could get a
good
idea of their permeability.
The last batch of the .19" I ordered were thinly-coated ferrite and
gives a
whopping 3uH per turn^2 - 10 turns of #28 (heavier wire will bind in
the
tiny hole) gave around 270uH. I stacked 2 of then together and got a
3000uH
inductor with just 16 turns!
The .30"-ID one is powdered iron, and is about 55uH with 10 turns.
QS
|
That's great info. I'm trying to figure out which it is. GO to this
URL and click on material 77, for example. It gives a chart of the
different sizes of cores. It looks like the FT37 size has the .19" ID
hole. But I'm not sure how the Al value corresponds.
http://www.bytemark.com/products/ferrmat.htm |
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Watson A.Name - \"Watt Su
Guest
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| Posted:
Wed Mar 23, 2005 1:01 pm Post subject:
Re: Toroid Core for LED V Boost |
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"Tim Williams" <tmoranwms@charter.net> wrote in message
news:UYY%d.4852$xo.2771@fe03.lga...
| Quote: | "Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com
wrote
in message news:113vkq81dj1ui7a@corp.supernews.com...
Cattle prod. Electric fence shocker. Neon light blinky supply.
Think up some more uses.
Jim Thompson prod, to keep him from posting OT threads. ;-)
Tim
|
Hey, if the foo sh!ts.. :-))
> -- |
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Tim Williams
Guest
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| Posted:
Wed Mar 23, 2005 1:47 pm Post subject:
Re: Toroid Core for LED V Boost |
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"Jim Thompson" <thegreatone@example.com> wrote in message
news:8do041956610drrle4561qcqeeojhd6p4q@4ax.com...
| Quote: | Jim Thompson prod, to keep him from posting OT threads. ;-)
Too bad you really don't know how to design one.
Fookin' amateurs ;-)
|
Um...okay... that was a rather akward post (even for you).
Tim
--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms |
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Watson A.Name - \"Watt Su
Guest
|
| Posted:
Wed Mar 23, 2005 2:42 pm Post subject:
Re: Toroid Core for LED V Boost |
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"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:Dq00e.14537$C47.11855@newssvr14.news.prodigy.com...
| Quote: | Hello Watson,
IMHO, if it really was important, one would see these gaps in
ferrite
toroids. But one doesn't.. (At least not in my experience.)
There are toroids where the ferrite is encapsulated in other stuff,
which essentially forms "micro gaps". But it can get expensive here.
|
Yeah, I think I mentioned that in an earlier followup.
Here's one that actually puts a gap in the toroid.
www.ferroxcube.com/appl/info/gaptoroids.pdf
The other URL talked about using MPP for the mixture. This is like
powdered iron in that the gaps are between the particles.
http://powerelectronics.com/mag/power_inductor_core_technology_2/
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Don Klipstein
Guest
|
| Posted:
Tue Apr 05, 2005 2:03 am Post subject:
Re: Toroid Core for LED V Boost |
|
|
In article <yPK%d.86$zl.82@newssvr13.news.prodigy.com>, Joerg wrote:
| Quote: | Hello John,
Voltage boost regulators store energy in the magnetic field of the
inductor first, and dump it to the load second. Ungapped ferrite
cores are not so efficient in this mode, since the core absorbs a
significant fraction of the energy stored, each cycle. ...
This depends on the material. The switchers I designed with non-gapped
toroids ran efficiently. The normal losses were all accounted for, such
as those in the transistor, the diode, the ESR etc. but pretty much none
in the inductor. No ringing, nice linear ramps and the cores didn't get
hot. Mostly Fair-Rite stuff.
|
The material could have been "Ferroxcube" 4C4 or some similar low
permeability ferrite.
- Don Klipstein (don@misty.com) |
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Joerg
Guest
|
| Posted:
Wed Apr 06, 2005 6:10 pm Post subject:
Re: Toroid Core for LED V Boost |
|
|
Hello Don,
| Quote: | This depends on the material. The switchers I designed with non-gapped
toroids ran efficiently. The normal losses were all accounted for, such
as those in the transistor, the diode, the ESR etc. but pretty much none
in the inductor. No ringing, nice linear ramps and the cores didn't get
hot. Mostly Fair-Rite stuff.
The material could have been "Ferroxcube" 4C4 or some similar low
permeability ferrite.
|
Low perm wouldn't make much sense in a switcher unless it runs at
several MHz. I usually take #77 material, Kaschke K2004/2006 or similar.
Regards, Joerg
http://www.analogconsultants.com |
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Jim Thompson
Guest
|
| Posted:
Wed Apr 06, 2005 9:10 pm Post subject:
Re: Toroid Core for LED V Boost |
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On Wed, 06 Apr 2005 17:57:34 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:
| Quote: | Hello Don,
This depends on the material. The switchers I designed with non-gapped
toroids ran efficiently. The normal losses were all accounted for, such
as those in the transistor, the diode, the ESR etc. but pretty much none
in the inductor. No ringing, nice linear ramps and the cores didn't get
hot. Mostly Fair-Rite stuff.
The material could have been "Ferroxcube" 4C4 or some similar low
permeability ferrite.
Low perm wouldn't make much sense in a switcher unless it runs at
several MHz. I usually take #77 material, Kaschke K2004/2006 or similar.
Regards, Joerg
http://www.analogconsultants.com
|
Toroids are treacherous unless you can guarantee perfect balance...
any DC is death... that's why, back in the days when I was SMPSing, I
preferred pot cores (or E-I, or E-E) WITH air-gaps.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
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Jim Thompson
Guest
|
| Posted:
Thu Apr 07, 2005 12:10 am Post subject:
Re: Toroid Core for LED V Boost |
|
|
On Wed, 06 Apr 2005 21:31:21 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:
| Quote: | Hello Jim,
Toroids are treacherous unless you can guarantee perfect balance...
any DC is death... that's why, back in the days when I was SMPSing, I
preferred pot cores (or E-I, or E-E) WITH air-gaps.
Yes, and that is a fairly little understood subject among engineers. A
saturated core behaves almost as if it wasn't there.
Most of the switchers I designed have a current mode loop which will
prevent such catastrophes. But I have seen designs without it that were
uncomfortably close to CCM. From there to kablouie it can be as little
as a few milliseconds. The resulting fireworks are usually quite impressive.
Regards, Joerg
http://www.analogconsultants.com
|
"kablouie" reminds of another fun event in my life...
One of the first off-line switchers I was designing (for
OmniComp/GenRad, ~1978) was of great interest to marketing, because it
would significantly decrease the weight of their portable tester
concept, called the PSP (Portable Service Processor).
So all these marketing clowns come trooping into my laboratory when
they got wind that I was testing it.
So they crowd around my workbench.
I warn them that it's not been powered up before and they should stand
back.
They ignore me.
I plug it in.
KABLOUIE!
Flame blew out of the (ferrite) transformer, then it burned back along
the line cord, back toward the receptacle, in a way reminiscent of the
way you see bomb fuses burn, before the breaker finally let go.
After the marketing types regained their skin color, they accused me
of setting the whole thing up to scare them ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
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Joerg
Guest
|
| Posted:
Thu Apr 07, 2005 12:10 am Post subject:
Re: Toroid Core for LED V Boost |
|
|
Hello Jim,
| Quote: | Toroids are treacherous unless you can guarantee perfect balance...
any DC is death... that's why, back in the days when I was SMPSing, I
preferred pot cores (or E-I, or E-E) WITH air-gaps.
|
Yes, and that is a fairly little understood subject among engineers. A
saturated core behaves almost as if it wasn't there.
Most of the switchers I designed have a current mode loop which will
prevent such catastrophes. But I have seen designs without it that were
uncomfortably close to CCM. From there to kablouie it can be as little
as a few milliseconds. The resulting fireworks are usually quite impressive.
Regards, Joerg
http://www.analogconsultants.com |
|
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