Toroid Core for LED V Boost

[John Popelish]

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.

--
John Popelish

 

Michael wrote:

I checked out a couple photo shops, hoping to get my hands on some disposable
camera flash guts as you(?) suggested, and was told at both places that they
don't toss disposables. They turn 'em in for cash. Ah well ...... some Zetex
goodies will be coming soon.


The one near me gets 25 cents per camera. At 4 for

a buck, you can't go wrong. The AA cell alone is
worth that.

Ed

 

[Joerg]

Hello John,

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.

Mostly 77 material and some more modern ones. Also, Kaschke K2004 and
K2006, plus some others for the 100-500kHz range. For frequencies in the
MHz range #43. Cost was usually a key factor so no boutique stuff.

Regards, Joerg

http://www.analogconsultants.com

 

[Watson A.Name - \"Watt Su]

"John Popelish" <jpopelish@rica.net> wrote in message
news:423E6137.576D86AD@rica.net...

Michael wrote:

This discussion has picqued my interest. I gotta fidn some more
"donuts" and
have at it.

Excellent! If you have trouble finding similar pairs, let me know and
I will mail you a few.

I found some 'donuts' - toroids on Ebay. The only problem is that
they're from a British seller, and I think the shipping costs might be
just a bit too high. They're white cores from Philips, I believe. I
did a search for ferrite -cables. The -cables is because there are a
lot of video cables and such for sale. Putting the minus to exclude
them gets the number of hits down to a reasonable size.

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.

--
John Popelish

 

[Watson A.Name - \"Watt Su]

"Fred Art" <rajabetawi@hotmail.com> wrote in message
news:Xns962160580DA02FArt@203.26.24.228...

Michael <NoSpam@att.net> while reading the NewsGroups, express out
opinion in news:423E5041.AFDA3AC@att.net:


I checked out a couple photo shops, hoping to get my hands on
some disposable camera flash guts as you(?) suggested, and was
told at both places that they don't toss disposables. They turn
'em in for cash. Ah well ...... some Zetex goodies will be
coming soon.

Check out Ebay stuff like this is available.

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&rd=1&item=7501877040
&ssPageName=STRK:MESE:IT

The one in the pic looks pretty much the same as the ones I got.

He forgot to tell that the transistors are good for making LED V boost
circuits.

Some of the toob nuts out here could use the 300VDC for their B+.

Cattle prod. Electric fence shocker. Neon light blinky supply.

Think up some more uses.

> F.Art

 

[QuantSuff]

"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

 

[Tim Williams]

"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

--
"California is the breakfast state: fruits, nuts and flakes."
Website: http://webpages.charter.net/dawill/tmoranwms

 

[Rich Grise]

On Mon, 21 Mar 2005 21:18:42 -0500, John Popelish wrote:

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

 

[Joerg]

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.

Regards, Joerg

http://www.analogconsultants.com

 

[Joerg]

Hello Watson,

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

 

[Watson A.Name - \"Watt Su]

"Tim Williams" <tmoranwms@charter.net> wrote in message
news:UYY%d.4852$xo.2771@fe03.lga...

"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.. )

> --

 

[Tim Williams]

"Jim Thompson" <thegreatone@example.com> wrote in message
news:8do041956610drrle4561qcqeeojhd6p4q@4ax.com...

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

 

[Watson A.Name - \"Watt Su]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
newsq00e.14537$C47.11855@newssvr14.news.prodigy.com...

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/

Regards, Joerg

http://www.analogconsultants.com

 

[Joerg]

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.

Regards, Joerg

http://www.analogconsultants.com

 

[Watson A.Name - \"Watt Su]

"John Popelish" <jpopelish@rica.net> wrote in message
news:423F8082.F395724C@rica.net...

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.

IMHO, if it really was important, one would see these gaps in ferrite
toroids. But one doesn't.. (At least not in my experience.)

One other factor, it's a lot easier to wind a bobbin compared to a
toroid. So one does see a lot of bobbins on gapped cores. I would
think that a gapped toroid wouldn't give any better performance than a
bobbin on a gapped core, so instead of pursuing this line of thought, we
should just cut to the chase and go with bobbins and gapped cores. Pot
cores would be another alternative.

--
John Popelish

 

[Watson A.Name - \"Watt Su]

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:7IL%d.236$FN4.218@newssvr21.news.prodigy.com...

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.

Regards, Joerg

http://www.analogconsultants.com

 

[Jim Thompson]

On Tue, 22 Mar 2005 11:53:57 -0600, "Tim Williams"
<tmoranwms@charter.net> wrote:

"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 Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Don Klipstein]

In article <yPK%d.86$zl.82@newssvr13.news.prodigy.com>, Joerg wrote:

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)

 

[Joerg]

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

 

[Jim Thompson]

On Wed, 06 Apr 2005 17:57:34 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

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 Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.