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Re: charge pump/boost converter
snipped-for-privacy@gmail.com says...
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Oh God, You just couldn't keep that failed OSC out of th subject!

Jamie


Re: charge pump/boost converter
On Sunday, July 19, 2015 at 1:49:42 AM UTC+2, M Philbrook wrote:
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ind  
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ND/4006941
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or - would work well. MOS-FET transistors do a bit better than bipolar tran
sistors, but Baxandall's paper rather pre-dates them.
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lator1.htm

The 1959 Baxandall class_D oscillator isn't "failed". To quote from my web-
site "The circuit is probably best known from Jim Williams' series of appli
cation notes for Linear Technology, on high frequency inverters for driving
 cold cathode back-lights used in laptop computers (application notes AN45,
 AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's  
most popular application notes for quite a while.

It has been claimed that Jim Williams got the circuit from England, without
 the Baxandall label.

I do have a low distortion variant of the class-D oscillator, with a curren
t mirror rather than the feed inductor, but that's not the low distortion o
scillator I'm working on at the moment.

You are distinctly public-spirited in regularly reminding us that you are a
n idiot, but you really don't have to do it quite as often as you do.

--  
Bill Sloman, Sydney  



Re: charge pump/boost converter
On 19/07/2015 18:26, Bill Sloman wrote:
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The circuit on your website bears a lot of resemblance to the one in  
Figure 2 of G3VA's Technical Topics column in Radio Communications  
magazine from May 2002. He refers to it as the "Mesny VHF power  
oscillator of the 1920s" though of course then it used triodes not  
MOSFETs, and needed a separate winding for the gates to get the DC bias  
right. There is a picture of it under the name Mesny here:
http://www.r-type.org/articles/art-106.htm

I think some people call them Kalitrons too:
http://www.vk6fh.com/vk6fh/kalitron.htm

It is one of the most popular topologies for on-chip LC oscillators in  
the synthesisers of cellphone radios - though usually with fancy  
amplitude control etc. and sometimes without the inductor in the supply,  
or with the supply inductor moved to the tail of the diff pair. Whatever  
it is called, it was a very old topology in 1959 and yet billions of  
them have been made in recent years.

Chris


Re: charge pump/boost converter
On Sunday, July 19, 2015 at 1:29:37 PM UTC+2, Chris Jones wrote:
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-ND/4006941
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u
ctor - would work well. MOS-FET transistors do a bit better than bipolar tr
ansistors, but Baxandall's paper rather pre-dates them.
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illator1.htm
web-site "The circuit is probably best known from Jim Williams' series of a
pplication notes for Linear Technology, on high frequency inverters for dri
ving cold cathode back-lights used in laptop computers (application notes A
N45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technolog
y's most popular application notes for quite a while.
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hout the Baxandall label.
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rrent mirror rather than the feed inductor, but that's not the low distorti
on oscillator I'm working on at the moment.
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re an idiot, but you really don't have to do it quite as often as you do.
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Jim William's version has the inductor in the tail of the differential pair
.

No inductor gives you a rather different beast, though I've used a current  
mirror to do much the same job to get a rather less distorted sine wave.

 "The circuit is probably best known from Jim Williams' series of applicati
on notes for Linear Technology, on high frequency inverters for driving col
d cathode back-lights used in laptop computers (application notes AN45, AN4
9, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most
 popular application notes for quite a while, so it's not surprising that t
he circuit is now well-known.  

Nobody has ever called it a Mesny power oscillator before anywhere I've loo
ked. Peter Baxandall seems to have invented the circuit to drive high-turns
 ration transformers to step up +12V supplies to a kilovolt or so to drive  
photomulitpliers.

That's not remotely a VHF circuit, though VHF circuits are presumably rathe
r more sensitive to the rather lower inter-winding capacitances seen in mor
e conventional transformers.

The Proceedings of the British Institute of Electrical Engineers is a peer-
reviewed journal so presumably the reviewers didn't see the similarity to t
he Mesny power amplifier either.

--  
Bill Sloman, Sydney






Re: charge pump/boost converter
snipped-for-privacy@gmail.com says...
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 You know as well I do what was meant by that  
comment..
  
Jamie


Re: charge pump/boost converter
On Sunday, July 19, 2015 at 6:03:34 PM UTC+2, M Philbrook wrote:
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web-site "The circuit is probably best known from Jim Williams' series of a
pplication notes for Linear Technology, on high frequency inverters for dri
ving cold cathode back-lights used in laptop computers (application notes A
N45, AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technolog
y's most popular application notes for quite a while.
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hout the Baxandall label.
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rrent mirror rather than the feed inductor, but that's not the low distorti
on oscillator I'm working on at the moment.
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re an idiot, but you really don't have to do it quite as often as you do.
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Sure - you don't like being shown up as an idiot. Sadly, the response ident
ified you as an idiot just as clearly as all the other rubbish you post.

--  
Bill Sloman, Sydney


Re: charge pump/boost converter
On Sun, 19 Jul 2015 01:26:33 -0700 (PDT), Bill Sloman

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---
As if it wasn't self-serving: "The circuit is probably best known from
Jim Williams' series of application notes for Linear Technology, on
high frequency inverters for driving cold cathode back-lights used in
laptop computers (application notes AN45, AN49, AN51, AN55, AN61,
AN65)." These apparently were Linear Technology's most popular
application notes for quite a while.

---
So what's your point?
---

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---
Got some proof?
---

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---
So why bring it up?
---

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---
Nor do you, but your proclivity toward attaining that goal seems to be
well founded.

John Fields
  

Re: charge pump/boost converter
On Tuesday, 1 September 2015 06:54:06 UTC+10, John Fields  wrote:
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-2-ND/4006941
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you
t
uctor - would work well. MOS-FET transistors do a bit better than bipolar t
ransistors, but Baxandall's paper rather pre-dates them.
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cillator1.htm
eb-site  
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The point was that what I was putting forward wasn't my low distortion osci
llator, but rather Peter Baxandall's Class-D oscillator, which has been a s
uccess story in a coupe of applications.

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out > >the Baxandall label.
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Someone from the UK e-mailed me the story about giving the Baxandall circui
t to a Linear Technology rep to answer a question that Jim Williams had had
 the reps put around. They weren't prepared to make a big revelation out of
 the story, which was old - Linear Technology's AN45 was published in 1991  
and the Baxandall style cold-cathode driver is figure 36 amongst a bunch of
 other circuits, so it goes back 25 years, and Jim Williams is dead.
  
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rent mirror rather than the feed inductor, but that's not the low distortio
n oscillator I'm working on at the moment.
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Completeness.
  
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e an idiot, but you really don't have to do it quite as often as you do.
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Your famous difficulties with comprehending complex sentences may influence
 that point of view.

And why post something now? You are reacting to a post I made on the 19th J
uly 2015. You are slow, but six weeks is a long time.

--  
Bill Sloman, Sydney


Re: charge pump/boost converter
On 01/09/2015 05:09, Bill Sloman wrote:
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The Royer and Jensen circuits go back to 1954 and 1957 respectively and  
so predate Baxandall. Both were still known in the late 70s textbooks.  
Are you saying that Jim Williams got the idea from Baxandall but  
credited Royer?

piglet

Re: charge pump/boost converter
On Tuesday, 1 September 2015 18:20:01 UTC+10, piglet  wrote:
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ithout > >the Baxandall label.
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rcuit to a Linear Technology rep to answer a question that Jim Williams had
 had the reps put around. They weren't prepared to make a big revelation ou
t of the story, which was old - Linear Technology's AN45 was published in 1
991 and the Baxandall style cold-cathode driver is figure 36 amongst a bunc
h of other circuits, so it goes back 25 years, and Jim Williams is dead.
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current mirror rather than the feed inductor, but that's not the low distor
tion oscillator I'm working on at the moment.
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The difference between Royer and Baxandall is the inductor in series with t
he centre-tap.

Royer doesn't have it, and produces square waves (usually with spikes at th
e switching transitions).

The Baxandall class-D oscillator produces sine waves. They aren't perfect s
ine waves, but a couple of percent of third order harmonic and progressivel
y less  higher order harmonics beat the pants off a Royer inverter.

http://www.butlerwinding.com/electronic-transformer-inverter-trans/

makes the Jensen inverter a variant of the Royer approach.  

Royer's paper, which I did see once, back in 1970, made a lot of fuss about
 using saturating transformer cores and driving them into saturation, which
 isn't actually necessary nor a good idea. Letting the drive transistors co
me out of saturation works just as well.

As far as I can tell, Jim Williams was given a copy of a schematic of a Bax
andall inverter, but no reference to Baxandall's 1959 paper, and cited Roye
r's paper as the closest thing he knew about to prior art. It was a bit sil
ly.

--  
Bill Sloman, Sydney


Re: charge pump/boost converter
On 01/09/2015 13:25, Bill Sloman wrote:
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Yes, I think it is a tricky topology to get pure sine waves from. When  
voltage fed you have to ensure a small non-conducting dead time when  
both transistors are off. When current fed (by inductor) that dead time  
would be lethal and instead an overlapping conduction time is necessary  
but that places both transistors as a dead short across the resonant  
tank. Is that why you are trying a current source instead of inductor?

piglet



Re: charge pump/boost converter
On Wednesday, 2 September 2015 04:06:13 UTC+10, piglet  wrote:
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ct sine waves, but a couple of percent of third order harmonic and progress
ively less  higher order harmonics beat the pants off a Royer inverter.
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The Baxandall circuit doesn't bother about non-conducting dead time - it pr
edates MOS-FET swtiches, and doesn't care much about both BJT transistors b
eing slightly on - but not saturated - at cross-over.

Life gets more complicated with MOS-FET swtiches.

http://sophia-elektronica.com/Baxandall_parallel-resonant_Class-D_oscillato
r5.htm

describes as circuit that's guaranteed to start-up (note the worst-case Vgs
 difference between the switching transistor models) and not draw too much  
current when it's working. It's not something I'd build in real life, but i
t works in LTSpice. The .asc file is on the web-site.

The current mirror delivers a tolerably pure half-sine wave current into th
e centre tap, which the inductor doesn't. There's nothing more to it than t
hat.  

--  
Bill Sloman, Sydney


Re: charge pump/boost converter
On Sat, 18 Jul 2015 19:53:31 -0400, M Philbrook

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It's an interesting circuit from a time scaling standpoint. It will
oscillate at tens of KHz, but it takes decades to build.



--  

John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: charge pump/boost converter
On Sunday, July 19, 2015 at 7:40:19 PM UTC+2, John Larkin wrote:
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o  
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kind  
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rder  
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-ND/4006941
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u
tor - would work well. MOS-FET transistors do a bit better than bipolar tra
nsistors, but Baxandall's paper rather pre-dates them.
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llator1.htm

John Larkin is too dim to notice the difference between a low distortion os
cillator and the Baxandall/Jim Williams oscillator.

 "The circuit is probably best known from Jim Williams' series of applicati
on notes for Linear Technology, on high frequency inverters for driving col
d cathode back-lights used in laptop computers (application notes AN45, AN4
9, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's most
 popular application notes for quite a while.  

Nobody has had any trouble building them in jig time. Except perhaps John L
arkin, who can't cope with transformers that he can't buy off the shelf.

--  
Bill Sloman, Sydney


Re: charge pump/boost converter
Den mandag den 20. juli 2015 kl. 17.24.11 UTC+2 skrev Bill Sloman:
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 so  
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t kind  
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-2-ND/4006941
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you
t
uctor - would work well. MOS-FET transistors do a bit better than bipolar t
ransistors, but Baxandall's paper rather pre-dates them.
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cillator1.htm
oscillator and the Baxandall/Jim Williams oscillator.
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Though it can hardly come as a surprise that you get teased about it since
  
you have been talking about for years and still haven't gotten around to bu
ilding it, as if a bit of table space for a soldering iron and time, for so
meone who doesn't have to go to work everyday, is impossible to find

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tion notes for Linear Technology, on high frequency inverters for driving c
old cathode back-lights used in laptop computers (application notes AN45, A
N49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's mo
st popular application notes for quite a while.  
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 Larkin, who can't cope with transformers that he can't buy off the shelf.
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Aiming to build stuff from things you can get cheap and fast off the shelf  
is just common sense

-Lasse

Re: charge pump/boost converter
On Tuesday, July 21, 2015 at 12:38:07 AM UTC+2, Lasse Langwadt Christensen  
wrote:
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or so  
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or so?  
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ust kind  
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73-2-ND/4006941
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d you
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nductor - would work well. MOS-FET transistors do a bit better than bipolar
 transistors, but Baxandall's paper rather pre-dates them.
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oscillator1.htm
n oscillator and the Baxandall/Jim Williams oscillator.
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e  
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r  
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I'd gotten most of the way to building an example - bought all the parts, i
ncluding getting the specially wound transformers - a few years ago, just b
efore I moved back to Australia, which gave me enough time to think up a be
tter variation, which I may get built real soon now, if I'm lucky.

It's not got much to do with Baxandall's class-D oscillator (though my vari
ant of that is what got me started) but Jamie and John are too dim to make  
that kind of fine distinction.
  
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cation notes for Linear Technology, on high frequency inverters for driving
 cold cathode back-lights used in laptop computers (application notes AN45,
 AN49, AN51, AN55, AN61, AN65)." These apparently were Linear Technology's  
most popular application notes for quite a while.  
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hn Larkin, who can't cope with transformers that he can't buy off the shelf
.
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f is just common sense

Restricting yourself to components which you can buy cheaply off the shelf  
rather narrows your range, particularly when it comes to transformers.  

--  
Bill Sloman, Sydney

Re: charge pump/boost converter
On 07/21/2015 11:46 AM, Bill Sloman wrote:
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with the outputs in series would work. They are fairly quiet, and you
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Oh God, You just couldn't keep that failed OSC out of th subject!
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Oh, I don't know about that.  A big PSU or one with special requirements  
might well need custom magnetics, and it probably pays to micro-optimize  
high volume designs.  For annual quantities of tens to hundreds, though,  
(where John lives and I aspire to) ;) the performance advantage probably  
doesn't pay for the increased pain in procurement.

SMPSes can be fun once in awhile, but doing vanilla ones as a steady  
diet must be booooorrrinnnggg.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: charge pump/boost converter
On Tue, 21 Jul 2015 11:52:23 -0400, Phil Hobbs

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Custom magnetics is a real pain. Winding them yourself is crazy; they
will wind up costing ten or more times what a commercial surface-mount
part would cost. Just a bobbin will cost more than an entire finished
inductor. Ordering them from a magnetics house takes weeks of waiting
and a lot of engineering work documenting the part.

It can take a little ingenuity to make a circuit from standard parts,
but there are tons of standard inductors available too.

There's seldom a justification for building an off-line switcher.
Things like wall-warts and MeanWell bricks are absurdly cheap and have
all the UL/CE/FCC stickers you would ever want.

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There are lots of interesting packaged switchers around these days,
like 7805 drop-in replacements, hybrid bucks with magnetics and caps,
tiny dc/dc converters; they tend to cluster in the $4 range. It's
seldom worth even the parts cost of making your own standard switcher;
well, some small synchronous bucks aren't too bad, like to go from +5
to +1.2 or something.

Time to move up the abstraction stack.


--  

John Larkin         Highland Technology, Inc
lunatic fringe electronics

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Re: charge pump/boost converter
Den tirsdag den 21. juli 2015 kl. 18.21.55 UTC+2 skrev John Larkin:
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I bough stack of these for prototypes: http://www.ebay.com/itm/171381728637
almost cheaper than buying a 7805

-Lasse


Re: charge pump/boost converter
On Tue, 21 Jul 2015 09:48:57 -0700 (PDT), Lasse Langwadt Christensen

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This series is really cool:

http://www.digikey.com/product-detail/en/P7805-Q24-S5-S/102-2705-ND/4009632

Depending on which of the pins you ground, it will convert a positive
input to a positive or negative output.


--  

John Larkin         Highland Technology, Inc
lunatic fringe electronics

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