Boost Converter Tutorial?

[Jim Thompson]

In the past I have designed boost converters in burst mode, with peak
current control, but never with a PWM-controlled loop.

Outputs: +5 @ 25mA, -5V @ 20mA

Can someone point me to a tutorial?

Thanks!

[Don't point me to an off-the-shelf part. This has to go into a
_custom_ chip... just a little thing... 1mm x 25mm :-]

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

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

[Phil Hobbs]

Jim Thompson wrote:
>
> In the past I have designed boost converters in burst mode, with peak
> current control, but never with a PWM-controlled loop.
>
> Outputs: +5 @ 25mA, -5V @ 20mA
>
> Can someone point me to a tutorial?
>
> Thanks!
>
> [Don't point me to an off-the-shelf part. This has to go into a
> _custom_ chip... just a little thing... 1mm x 25mm :-]

Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
right?

Cheers

Phil Hobbs

[Jim Thompson]

Nope. It goes in something that virtually every person owns :-)

[Phil Hobbs]

Jim Thompson wrote:
>
> On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
> >Jim Thompson wrote:
> >>
> >> In the past I have designed boost converters in burst mode, with peak
> >> current control, but never with a PWM-controlled loop.
> >>
> >> Outputs: +5 @ 25mA, -5V @ 20mA
> >>
> >> Can someone point me to a tutorial?
> >>
> >> Thanks!
> >>
> >> [Don't point me to an off-the-shelf part. This has to go into a
> >> _custom_ chip... just a little thing... 1mm x 25mm :-]
> >
> >Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
> >right?
> >
> >Cheers
> >
> >Phil Hobbs
>
> Nope. It goes in something that virtually every person owns :-)
>
> ...Jim Thompson

So you decided to take someone's advice about what to do with your
design?

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

[Martin Riddle]

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote
in message news:m3cdj7hc1nqt27bn0...@4ax.com...

> In the past I have designed boost converters in burst mode, with peak
> current control, but never with a PWM-controlled loop.
>
> Outputs: +5 @ 25mA, -5V @ 20mA
>
> Can someone point me to a tutorial?
>
> Thanks!
>
> [Don't point me to an off-the-shelf part. This has to go into a
> _custom_ chip... just a little thing... 1mm x 25mm :-]
>
> ...Jim Thompson
> --

TI app notes?
<http://www.ti.com/analog/docs/analogtechdoc_hh.tsp?viewType=mostuseful&rootFamilyId=64&familyId=661&docTitle=boost&docCategoryId=1>

The 3525 has been around for a long time...
Maybe DN-62 has what your looking for.
<http://www.ti.com/product/uc3525b>

cheers

[brent]

On Feb 11, 1:26 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-

> | E-mail Icon athttp://www.analog-innovations.com|    1962     |

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

Twenty questions!

Is it for a tracking chip that goes into people's necks?

[Jim Thompson]

On Sat, 11 Feb 2012 13:34:08 -0500, Phil Hobbs

<pcdhSpamM...@electrooptical.net> wrote:

>Jim Thompson wrote:
>>
>> On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
>> <pcdhSpamM...@electrooptical.net> wrote:
>>
>> >Jim Thompson wrote:
>> >>
>> >> In the past I have designed boost converters in burst mode, with peak
>> >> current control, but never with a PWM-controlled loop.
>> >>
>> >> Outputs: +5 @ 25mA, -5V @ 20mA
>> >>
>> >> Can someone point me to a tutorial?
>> >>
>> >> Thanks!
>> >>
>> >> [Don't point me to an off-the-shelf part. This has to go into a
>> >> _custom_ chip... just a little thing... 1mm x 25mm :-]
>> >
>> >Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
>> >right?
>> >
>> >Cheers
>> >
>> >Phil Hobbs
>>
>> Nope. It goes in something that virtually every person owns :-)
>>
>> ...Jim Thompson
>
>So you decided to take someone's advice about what to do with your
>design?
>
>Cheers
>
>Phil Hobbs

This is but a small portion of the whole chip. As I said, I have no
experience (*) with PWM'd boost converters, though lots of those with
low output current, running burst mode (they have little or no
stability issues).

As Larkin would snark, If you've got something technical to say, then
say it, otherwise STFU :-{)

(*) Unlike some posters lurking here, I readily admit areas of which I
have little or no expertise. Then I listen, learn and ultimately
become the expert ;-)

[linnix]

On Feb 11, 10:26 am, Jim Thompson <To-Email-Use-The-Envelope-I...@On-

My-Web-Site.com> wrote:
> On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
>
>
>
>
>
>
>
>
>
> <pcdhSpamMeSensel...@electrooptical.net> wrote:
> >Jim Thompson wrote:
>
> >> In the past I have designed boost converters in burst mode, with peak
> >> current control, but never with a PWM-controlled loop.
>
> >> Outputs: +5 @ 25mA, -5V @ 20mA
>
> >> Can someone point me to a tutorial?
>
> >> Thanks!
>
> >> [Don't point me to an off-the-shelf part.  This has to go into a
> >> _custom_ chip... just a little thing... 1mm x 25mm :-]
>
> >Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
> >right?
>
> >Cheers
>
> >Phil Hobbs
>
> Nope.  It goes in something that virtually every person owns :-)

What is the power source? I don't think they make batteries that
thin.

[Jim Thompson]

Thanks, Martin! I owe you another sip or two or...

Though probably at some other location than Long Island. I sent those
horse's-asses in Huntington (and only you will appreciate why I say
that) an E-mail, "As I sit here in Rochester, in my _office_ (with a
_door_), looking out my _window_ at the melting snow, with a
_door-pass_ badge hanging around my neck, and with my laptop sitting
there connected to the customer's _network_ and the _Internet_, I was
thinking of you fellows at @#$%... >:-} "

I doubt they'll invite me back ;-) Though you never know... I was the
only one who could convey to Cadence what was needed with the "w-real"
modeling.

[Jim Thompson]

2.3-5V Battery.

[TTman]

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in

message news:ckcdj752sf9bdk5cu...@4ax.com...

> On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
> <pcdhSpamM...@electrooptical.net> wrote:
>
>>Jim Thompson wrote:
>>>
>>> In the past I have designed boost converters in burst mode, with peak
>>> current control, but never with a PWM-controlled loop.
>>>
>>> Outputs: +5 @ 25mA, -5V @ 20mA
>>>
>>> Can someone point me to a tutorial?
>>>
>>> Thanks!
>>>
>>> [Don't point me to an off-the-shelf part. This has to go into a
>>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>>
>>Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
>>right?
>>
>>Cheers
>>
>>Phil Hobbs
>
> Nope. It goes in something that virtually every person owns :-)

That'll be a watch then....

[Jamie]

I was going to say a tooth brush but, I've been in parts where that
maybe not be true :)

Jamie

[Jim Thompson]

On Sat, 11 Feb 2012 19:44:16 -0000, "TTman" <pcw1...@ntlworld.com>
wrote:

No. Think teenagers... what are they never seen without ?:-)

[Tim Wescott]

On Sat, 11 Feb 2012 11:22:38 -0700, Jim Thompson wrote:

> In the past I have designed boost converters in burst mode, with peak
> current control, but never with a PWM-controlled loop.
>
> Outputs: +5 @ 25mA, -5V @ 20mA
>
> Can someone point me to a tutorial?
>
> Thanks!
>
> [Don't point me to an off-the-shelf part. This has to go into a
> _custom_ chip... just a little thing... 1mm x 25mm :-]

Actually, I'd go looking at off-the-shelf parts to snag ideas from.

Efficiency? Regulation bounds? % of total product cost that'll be taken
up by the converter?

Unless the above answers are "low, loose, and low", I think your biggest
challenge won't be the silicon, it'll be finding small, economical & high
performance inductors, designing the thing to take advantage of them, and
dancing around the inevitable unstable zero in the boost converter.

Are you planning on paying for the 0.3V drop of a Schottkey on each
supply, or the time & trouble to drive the extra two switches & make it
synchronous?

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

[TTman]

>>
>
> No. Think teenagers... what are they never seen without ?:-)
>

Decent clothes ? lol
U seen the ones in the UK where their pants crotch comes down to their knees
.... PMSL

Doh that dreaded thumb rattling Mobile :(
Got any good designs for a blocker ????

[TTman]

"Tim Wescott" <t...@seemywebsite.please> wrote in message
news:SLKdnamUgb08VavS...@web-ster.com...

He's a real tease.. probably got all that sorted already....

[Tim Wescott]

Well, I would hope so. But you could do everything he's asking for with
a couple of charge pumps followed by linear regulators, if you didn't
mind the inefficiency.

[Jim Thompson]

On Sat, 11 Feb 2012 20:00:36 -0000, "TTman" <pcw1...@ntlworld.com>
wrote:

No blocker. But I understand that new movie theater installs in the
US are shielded sufficiently that cell phones don't function in the
auditorium portion of the facility. I know that at least one theater
I frequent requests that doctors leave their cell phones and pagers at
the front desk if they're "on-call"... an usher will come and notify
them as needed.

[Jim Thompson]

On Sat, 11 Feb 2012 13:59:29 -0600, Tim Wescott
<t...@seemywebsite.please> wrote:

>On Sat, 11 Feb 2012 11:22:38 -0700, Jim Thompson wrote:
>
>> In the past I have designed boost converters in burst mode, with peak
>> current control, but never with a PWM-controlled loop.
>>
>> Outputs: +5 @ 25mA, -5V @ 20mA
>>
>> Can someone point me to a tutorial?
>>
>> Thanks!
>>
>> [Don't point me to an off-the-shelf part. This has to go into a
>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>
>Actually, I'd go looking at off-the-shelf parts to snag ideas from.
>
>Efficiency?

As high as practical.

>Regulation bounds?

Loose. Lots of compensating innards for power supply variation.

> % of total product cost that'll be taken
>up by the converter?

They've already committed to external switch(es)

>
>Unless the above answers are "low, loose, and low", I think your biggest
>challenge won't be the silicon, it'll be finding small, economical & high
>performance inductors, designing the thing to take advantage of them, and
>dancing around the inevitable unstable zero in the boost converter.

The inductor _is_ a problem. They're already at their height limit
and their present implementation (at lower current) is just pushing
into saturation :-(

>
>Are you planning on paying for the 0.3V drop of a Schottkey on each
>supply, or the time & trouble to drive the extra two switches & make it
>synchronous?

That's up for debate.

But this client is no onesy-twosy outfit... they just shipped their
BILLIONETH chip!

[Jim Thompson]

Try 32 Ohm "bumps" and you see another aspect of the problem :-(

[Ian Field]

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in

message news:i5fdj71se8ju71to9...@4ax.com...

Yeahbut you tried to cram a burst mode at one of my questions and I hadn't
even asked for a design.

It wasn't because burst mode was best for my app, it was because you didn't
know PWM - not exactly honest was it.

[legg]

On Sat, 11 Feb 2012 11:22:38 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>In the past I have designed boost converters in burst mode, with peak
>current control, but never with a PWM-controlled loop.
>
>Outputs: +5 @ 25mA, -5V @ 20mA
>
>Can someone point me to a tutorial?
>
>Thanks!
>
>[Don't point me to an off-the-shelf part. This has to go into a
>_custom_ chip... just a little thing... 1mm x 25mm :-]
>
> ...Jim Thompson

Input?

RL

[Phil Hobbs]

Like you, right?

[TTman]

>
> The inductor _is_ a problem. They're already at their height limit
> and their present implementation (at lower current) is just pushing
> into saturation :-(
>
>>
>>Are you planning on paying for the 0.3V drop of a Schottkey on each
>>supply, or the time & trouble to drive the extra two switches & make it
>>synchronous?
>
> That's up for debate.
>
> But this client is no onesy-twosy outfit... they just shipped their
> BILLIONETH chip!

I bet they'll pay you an ARM and a leg for the right solution<snigger>

[Martin Riddle]

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote
in message news:1mfdj7l31utddhcf8...@4ax.com...

Snicker...

I also came across a voltage vs. current move paper by TI (maybe
unitrode) not sure.
That may have something in it too.

It should be some where in those links above.

Cheers

[MarkK]

> I bet they'll pay you an ARM and a leg for the right solution<snigger>
>
>

the old unitrode seminars are the best

http://www.smps.us/Unitrode.html

Mark

[Spehro Pefhany]

On Sat, 11 Feb 2012 11:26:18 -0700, the renowned Jim Thompson
<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
><pcdhSpamM...@electrooptical.net> wrote:
>
>>Jim Thompson wrote:
>>>
>>> In the past I have designed boost converters in burst mode, with peak
>>> current control, but never with a PWM-controlled loop.
>>>
>>> Outputs: +5 @ 25mA, -5V @ 20mA
>>>
>>> Can someone point me to a tutorial?
>>>
>>> Thanks!
>>>
>>> [Don't point me to an off-the-shelf part. This has to go into a
>>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>>
>>Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
>>right?
>>
>>Cheers
>>
>>Phil Hobbs
>
>Nope. It goes in something that virtually every person owns :-)
>
> ...Jim Thompson

Display driver.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

[Tim Wescott]

Oh joy -- so, do you have the frequency headroom to use a lower
inductance coil with the same core, to get the saturation current up?

--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?

Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com

[bitrex]

On 2/11/2012 3:18 PM, Jim Thompson wrote:
> On Sat, 11 Feb 2012 13:59:29 -0600, Tim Wescott
> <t...@seemywebsite.please> wrote:
>
>> On Sat, 11 Feb 2012 11:22:38 -0700, Jim Thompson wrote:
>>
>>> In the past I have designed boost converters in burst mode, with peak
>>> current control, but never with a PWM-controlled loop.
>>>
>>> Outputs: +5 @ 25mA, -5V @ 20mA
>>>
>>> Can someone point me to a tutorial?
>>>
>>> Thanks!
>>>
>>> [Don't point me to an off-the-shelf part. This has to go into a
>>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>>
>> Actually, I'd go looking at off-the-shelf parts to snag ideas from.
>>
>> Efficiency?
>
> As high as practical.
>
>> Regulation bounds?
>
> Loose. Lots of compensating innards for power supply variation.
>
>> % of total product cost that'll be taken
>> up by the converter?
>
> They've already committed to external switch(es)
>
>>
>> Unless the above answers are "low, loose, and low", I think your biggest

>> challenge won't be the silicon, it'll be finding small, economical& high

>> performance inductors, designing the thing to take advantage of them, and
>> dancing around the inevitable unstable zero in the boost converter.
>
> The inductor _is_ a problem. They're already at their height limit
> and their present implementation (at lower current) is just pushing
> into saturation :-(
>

Has the value of inductor been selected properly? The rule of thumb for
a boost converter in continuous conduction mode is L = (V *
D)/(R*I_l*f), where the parameters are evaluated at the _lowest_
specified (worst case for a boost) input voltage. V is the input
voltage, I_l is the DC inductor current (I_o/(1-D)), D is the duty
cycle, f is the switching frequency. R is the "ripple current ratio"
and has an optimum value of 0.4 for continuous conduction mode in most
cases.

At low voltages the inductor can be sized solely based on the DC load
current requirements - if the current limiting is fast enough it doesn't
matter if the inductor saturates under abnormal conditions.

If the inductor is still too big maybe use discontinuous mode instead?
It'll be harder to stabilize, unfortunately.

[who where]

On Sat, 11 Feb 2012 11:26:18 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
><pcdhSpamM...@electrooptical.net> wrote:
>

>>Jim Thompson wrote:
>>>
>>> In the past I have designed boost converters in burst mode, with peak
>>> current control, but never with a PWM-controlled loop.
>>>
>>> Outputs: +5 @ 25mA, -5V @ 20mA
>>>
>>> Can someone point me to a tutorial?
>>>
>>> Thanks!
>>>
>>> [Don't point me to an off-the-shelf part. This has to go into a
>>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>>

>>Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
>>right?
>>
>>Cheers
>>
>>Phil Hobbs
>
>Nope. It goes in something that virtually every person owns :-)

Car ignition key?

[Jim Thompson]

On Sat, 11 Feb 2012 18:20:30 -0500, Spehro Pefhany
<spef...@interlogDOTyou.knowwhat> wrote:

>On Sat, 11 Feb 2012 11:26:18 -0700, the renowned Jim Thompson
><To-Email-Use-Th...@On-My-Web-Site.com> wrote:
>
>>On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
>><pcdhSpamM...@electrooptical.net> wrote:
>>
>>>Jim Thompson wrote:
>>>>
>>>> In the past I have designed boost converters in burst mode, with peak
>>>> current control, but never with a PWM-controlled loop.
>>>>
>>>> Outputs: +5 @ 25mA, -5V @ 20mA
>>>>
>>>> Can someone point me to a tutorial?
>>>>
>>>> Thanks!
>>>>
>>>> [Don't point me to an off-the-shelf part. This has to go into a
>>>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>>>
>>>Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
>>>right?
>>>
>>>Cheers
>>>
>>>Phil Hobbs
>>
>>Nope. It goes in something that virtually every person owns :-)
>>
>> ...Jim Thompson
>
>Display driver.
>
>
>Best regards,
>Spehro Pefhany

Of course ;-)

[Jim Thompson]

On Sat, 11 Feb 2012 19:21:29 -0600, Tim Wescott <t...@seemywebsite.com>

That's where my thoughts are progressing...

[bitrex]

>>> supply, or the time& trouble to drive the extra two switches& make it

>>> synchronous?
>>
>> That's up for debate.
>>
>> But this client is no onesy-twosy outfit... they just shipped their
>> BILLIONETH chip!
>
> Oh joy -- so, do you have the frequency headroom to use a lower
> inductance coil with the same core, to get the saturation current up?
>

Just how big does this inductor have to be? Looking here:
http://www.panasonic.com/industrial/components/pdf/AGA0000CE34.pdf

A 100 uH 150 mA inductor looks like it could be a chip inductor a few mm
high.

[Michael A. Terrell]

Jim Thompson wrote:
>
> No. Think teenagers... what are they never seen without ?:-)

A stupid look on their face as they ignore you? ;-)


--
You can't have a sense of humor, if you have no sense.

[Wond]

On Sat, 11 Feb 2012 13:34:08 -0500, Phil Hobbs wrote:

> Jim Thompson wrote:
>>

>> On Sat, 11 Feb 2012 13:25:00 -0500, Phil Hobbs
>> <pcdhSpamM...@electrooptical.net> wrote:
>>

>> >Jim Thompson wrote:
>> >>
>> >> In the past I have designed boost converters in burst mode, with
>> >> peak current control, but never with a PWM-controlled loop.
>> >>
>> >> Outputs: +5 @ 25mA, -5V @ 20mA
>> >>
>> >> Can someone point me to a tutorial?
>> >>
>> >> Thanks!
>> >>
>> >> [Don't point me to an off-the-shelf part. This has to go into a
>> >> _custom_ chip... just a little thing... 1mm x 25mm :-]
>> >

>> >Hmm, an inch long and a millimeter wide--it's for a robotic cockroach,
>> >right?
>> >
>> >Cheers
>> >
>> >Phil Hobbs
>>
>> Nope. It goes in something that virtually every person owns :-)
>>
>> ...Jim Thompson
>

> So you decided to take someone's advice about what to do with your
> design?
>
> Cheers
>
> Phil Hobbs

nnnnkkkkkk-splutter.. :D

[dagmarg...@yahoo.com]

But 4 ohms d.c.r. means it'll drop 600mV @ 150mA. Increasing f by a
factor of 3 reduces i^2*r loss by that same factor. Or, keep the loss
and trade for a smaller L and C.

Switching inductors without magnetic shields make RFI, magnetic
nasties, etc. Shielded are better.

--
Cheers,
James Arthur

[John Fields]

---
Your "questions" are little more than trolls designed to attract and
focus attention on you and, since you asked for "help" and it was
offered and you rejected it, out of hand, you're an ingrate with an
agenda disparate from ours, which is to help.
---

>It wasn't because burst mode was best for my app, it was because you didn't
>know PWM - not exactly honest was it.

---
If he didn't know PWM and offered you burst mode instead, why was that
dishonest at the time?

After all, he did the best he could, with what he had at hand, which
was better than anything you could come up with, since you were the
one asking for help.

--
JF

[Ian Field]

"John Fields" <jfi...@austininstruments.com> wrote in message
news:pbgjj75oo0aj4iue4...@4ax.com...

Do try to pay attention sometimes!

All I asked for was load curves for bicycle dynamos.

I didn't ask anyone to design it for me - I already have that well in hand.

I didn't reject the few (unsolicited) solutions from the minority of
smart-asses pretending to know more than they did - I just ignored them.

[John Fields]

---
Well, since ignorance seems to be your strong suit, that was probably
a good move on your part.

--
JF

[Ian Field]

"John Fields" <jfi...@austininstruments.com> wrote in message

news:hsqkj7l47sh69jibr...@4ax.com...

Well I certainly saved myself some aggro by ignoring the unsuitable topology
suggested by your chum.

Can't help wondering whether he'd have got it right if he had known how to
do the correct way.

[Jim Thompson]

Ian _and_ a notable other poster on this topic are severely ignorant
about the real world.

PWM BUCK is trivial. I chose BURST for the hub dynamo because it
would be a freebie around the 555, and I was intent on rubbing the 555
up some snobbish noses ;-)

PWM BOOST is NOT trivial, though I'm well on my way to an off-the-wall
STABLE solution... found by running the math instead of my mouth.

[John Larkin]

> ...Jim Thompson

Why does a self-proclaimed Master Circuit Designer need a tutorial on
something so basic? And why can't he use Google to find it?


--

John Larkin, President
Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro acquisition and simulation

[Paul Hovnanian P.E.]

Jim Thompson wrote:

> In the past I have designed boost converters in burst mode, with peak
> current control, but never with a PWM-controlled loop.
>
> Outputs: +5 @ 25mA, -5V @ 20mA
>
> Can someone point me to a tutorial?
>
> Thanks!
>
> [Don't point me to an off-the-shelf part. This has to go into a
> _custom_ chip... just a little thing... 1mm x 25mm :-]
>

> ...Jim Thompson

I have a Fairchild app note: AN-4105 that I've refereed to on occasion. Its
for their line of power switch products, but its got some block diagrams,
formulas, graphs and whatnot that are generic and describe operational
issues.


--
Paul Hovnanian mailto:Pa...@Hovnanian.com
------------------------------------------------------------------
Broken pipe. Command flooded basement.

[Jim Thompson]

On Tue, 14 Feb 2012 11:10:47 -0800, "Paul Hovnanian P.E."
<pa...@hovnanian.com> wrote:

>Jim Thompson wrote:
>
>> In the past I have designed boost converters in burst mode, with peak
>> current control, but never with a PWM-controlled loop.
>>
>> Outputs: +5 @ 25mA, -5V @ 20mA
>>
>> Can someone point me to a tutorial?
>>
>> Thanks!
>>
>> [Don't point me to an off-the-shelf part. This has to go into a
>> _custom_ chip... just a little thing... 1mm x 25mm :-]
>>
>> ...Jim Thompson
>
>I have a Fairchild app note: AN-4105 that I've refereed to on occasion. Its
>for their line of power switch products, but its got some block diagrams,
>formulas, graphs and whatnot that are generic and describe operational
>issues.
>
>

Thanks! Looks like a good reference.

[Jim Thompson]

If you were paying attention, and not just out to be a horse's ass,
you'd note that I said I'd done a low current discontinuous _boost_
regulator many years ago, but not done a PWM continuous mode before.

But I am indeed a master circuit designer. SPECIFY me a function and
I can do it. I just didn't (note the past tense) know the intricacies
of fancy boost regulators ;-)

Google yields piles of unqualified crap. Friends give guidance, for
which I am greatly appreciative! You are an enemy out to convince
everyone how brilliant you are, at the expense of anyone who gets in
your way. In fact, you're mediocrity personified. And, if you think
it's so basic, give us all a primer. We're all in need of a good
laugh ;-)

[John Fields]

On Tue, 14 Feb 2012 14:17:54 -0000, "Ian Field"

<gangprob...@ntlworld.com> wrote:

>
>"John Fields" <jfi...@austininstruments.com> wrote in message
>news:hsqkj7l47sh69jibr...@4ax.com...
>> On Tue, 14 Feb 2012 13:14:29 -0000, "Ian Field"
>> <gangprob...@ntlworld.com> wrote:
>>
>>
>>>I didn't reject the few (unsolicited) solutions from the minority of
>>>smart-asses pretending to know more than they did - I just ignored them.
>>
>> ---
>> Well, since ignorance seems to be your strong suit, that was probably
>> a good move on your part.
>
>Well I certainly saved myself some aggro by ignoring the unsuitable topology
>suggested by your chum.

---
"Aggro"?

Oh, my, how cute!

If you ignored it, then there's no way you could have determined
whether it was suitable or not.
---

>Can't help wondering whether he'd have got it right if he had known how to
>do the correct way.

---
Your pretending to knowledge of the _correct_ way insinuates that
you're privy to information which you obviously don't possess, since
you admit to wondering.

That makes you a phony.

Jim's made a good life for himself and his family, has certainly
contributed more than it seems _you_ ever will toward making this
world a better place in which to live, and yet all you can do is hurl
insolence from the peanut gallery.

Just a little envious, are we?

--
JF

[Jim Thompson]

Perhaps Ian, upon completion of his engineering degree, will grace us
with an elegant solution to the hub dynamo problem ?:-)

My only regret is that I wasted time trying to help Ian. It'll not
happen again.

[Jim Thompson]

On Tue, 14 Feb 2012 13:14:29 -0000, "Ian Field"

Well? Then show us how wonderful your design is.

>
>I didn't reject the few (unsolicited) solutions from the minority of
>smart-asses pretending to know more than they did - I just ignored them.
>

You "ignore" because you are "ignorant".

[Ian Field]

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in

message news:et5mj71t40jmps43f...@4ax.com...

Thought you were running the math, not your mouth!

[John Fields]

On Wed, 15 Feb 2012 21:12:02 -0000, "Ian Field"

---
I think neither is probable.
---

>> My only regret is that I wasted time trying to help Ian. It'll not
>> happen again.
>>
>> ...Jim Thompson
>
>
>Thought you were running the math, not your mouth!

---
You seem capable of understanding only the latter, since you were
flummoxed by not being able to get the former.

--
JF

[John Larkin]

On Wed, 15 Feb 2012 21:12:02 -0000, "Ian Field"

Gosh, just how much help was he?


--

John Larkin, President Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

[Ian Field]

"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message
news:2m0pj7dsa0h0i70ou...@4ax.com...

Dunno' - these days I just stand back and watch the amusing antics.

[josephkk]

On Sat, 11 Feb 2012 11:22:38 -0700, Jim Thompson

<To-Email-Use-Th...@On-My-Web-Site.com> wrote:

>In the past I have designed boost converters in burst mode, with peak
>current control, but never with a PWM-controlled loop.
>
>Outputs: +5 @ 25mA, -5V @ 20mA
>
>Can someone point me to a tutorial?
>
>Thanks!
>
>[Don't point me to an off-the-shelf part. This has to go into a
>_custom_ chip... just a little thing... 1mm x 25mm :-]
>

> ...Jim Thompson

OK it is not in my proper range of expertise, but there has to be a reason
that the device is not 2.5 mm by 10 mm (or even more square). Can you
enlighten us?

[Tim Williams]

Somewhere I believe LCD was mentioned. Typically TFTs have a little silicon
chip cemented to the glass, providing interface (parallel, serial,
whatever), control (for at least a buffer, if not some rudimentary fill
routines), memory, and most importantly, the massive fanout (hundreds of
rows and columns) required to drive the array itself (which is mainly crummy
amorphous transistors driving pads which finally drive the liquid crystal).
Last one I busted open had a shiny strip maybe 2 x 15 mm, a hi-def panel
would have a lot more. Probably progress has been made since then and only
a 1mm strip is required.

Putting inductors anywhere near one of those will be an interesting
challenge, because the few components that come with are soldered to the
flex cable. This includes bypass caps, which you may know from experience
do not handle strain very well...

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms

"josephkk" <joseph_...@sbcglobal.net> wrote in message
news:3iqrj7psde7l8bmg7...@4ax.com...

[Phil Hobbs]

I suspect it's a 1 mm sliver of a larger IC. Dicing yield would be a
problem with something 40 thou wide and an inch long, not to mention the
tendency of the chips to fall over. ;)

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

[Jim Thompson]

Nope. The real deal is 1mm x 25mm, with 480 "bumps". And this client
just sold their BILLIONETH chip, so they're not amateurs.

[Spehro Pefhany]

On Fri, 17 Feb 2012 10:20:10 -0500, the renowned Phil Hobbs
<pcdhSpamM...@electrooptical.net> wrote:

>
>
>
>I suspect it's a 1 mm sliver of a larger IC. Dicing yield would be a
>problem with something 40 thou wide and an inch long, not to mention the
>tendency of the chips to fall over. ;)

Here's a smaller example of this genre of chip:
http://www.tstonramp.com/~pddwebacc/ics_app%20notes/solomon/ssd-1805%20-1_4.pdf

11mm x 1.21mm.

They're used in zillions of LCD (and I guess OLED) panels in all kinds
of consumer goods (cell phones, GPS units, printer and camera displays
etc. etc.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

[Jim Thompson]

On Fri, 17 Feb 2012 18:58:51 -0500, Spehro Pefhany
<spef...@interlogDOTyou.knowwhat> wrote:

>On Fri, 17 Feb 2012 10:20:10 -0500, the renowned Phil Hobbs
><pcdhSpamM...@electrooptical.net> wrote:
>
>>
>>
>>
>>I suspect it's a 1 mm sliver of a larger IC. Dicing yield would be a
>>problem with something 40 thou wide and an inch long, not to mention the
>>tendency of the chips to fall over. ;)
>
>Here's a smaller example of this genre of chip:
>http://www.tstonramp.com/~pddwebacc/ics_app%20notes/solomon/ssd-1805%20-1_4.pdf
>
>11mm x 1.21mm.
>
>They're used in zillions of LCD (and I guess OLED) panels in all kinds
>of consumer goods (cell phones, GPS units, printer and camera displays
>etc. etc.
>
>
>Best regards,
>Spehro Pefhany

Yes ;-)

[Tom Del Rosso]

Jim Thompson wrote:
>
> PWM BOOST is NOT trivial, though I'm well on my way to an off-the-wall
> STABLE solution... found by running the math instead of my mouth.

Off the wall in what way?


--

Reply in group, but if emailing add one more
zero, and remove the last word.

[Jim Thompson]

On Sun, 19 Feb 2012 20:34:28 -0500, "Tom Del Rosso"
<td...@verizon.net.invalid> wrote:

>
>Jim Thompson wrote:
>>
>> PWM BOOST is NOT trivial, though I'm well on my way to an off-the-wall
>> STABLE solution... found by running the math instead of my mouth.
>
>Off the wall in what way?

In ways I will apply for patent, then explain ;-)

[Tom Del Rosso]

Jim Thompson wrote:
> On Sun, 19 Feb 2012 20:34:28 -0500, "Tom Del Rosso"
> <td...@verizon.net.invalid> wrote:
>
> >
> > Jim Thompson wrote:
> > >
> > > PWM BOOST is NOT trivial, though I'm well on my way to an
> > > off-the-wall STABLE solution... found by running the math instead
> > > of my mouth.
> >
> > Off the wall in what way?
>
> In ways I will apply for patent, then explain ;-)

So it's totally wacky then.

:)

[John Larkin]

On Tue, 21 Feb 2012 00:45:00 -0500, "Tom Del Rosso"

<td...@verizon.net.invalid> wrote:

>
>Jim Thompson wrote:
>> On Sun, 19 Feb 2012 20:34:28 -0500, "Tom Del Rosso"
>> <td...@verizon.net.invalid> wrote:
>>
>> >
>> > Jim Thompson wrote:
>> > >
>> > > PWM BOOST is NOT trivial, though I'm well on my way to an
>> > > off-the-wall STABLE solution... found by running the math instead
>> > > of my mouth.
>> >
>> > Off the wall in what way?
>>
>> In ways I will apply for patent, then explain ;-)
>
>So it's totally wacky then.
>
>:)

Continuous-mode PWM boost is just one baby step past trivial. All you
minimally need to do is limit the ON duty cycle to a modest amount
past what you need to overcome losses, to avoid the 100% ON
singularity. It's been done zillions of times. If a uP is generating
the PWM, you can do a smart algorithm with nice ramp-ups and stable
current limiting.

[Jim Thompson]

On Tue, 21 Feb 2012 00:45:00 -0500, "Tom Del Rosso"

<td...@verizon.net.invalid> wrote:

>
>Jim Thompson wrote:
>> On Sun, 19 Feb 2012 20:34:28 -0500, "Tom Del Rosso"
>> <td...@verizon.net.invalid> wrote:
>>
>> >
>> > Jim Thompson wrote:
>> > >
>> > > PWM BOOST is NOT trivial, though I'm well on my way to an
>> > > off-the-wall STABLE solution... found by running the math instead
>> > > of my mouth.
>> >
>> > Off the wall in what way?
>>
>> In ways I will apply for patent, then explain ;-)
>
>So it's totally wacky then.
>
>:)

Of course. That's my specialty... be different :-)

[Jim Thompson]

I'm sure glad everything is trivial for his majesty.

[John Larkin]

Not everthing, but continuous-mode, PWM controlled boost has been done
for about 0.4 century now. I doubt there's anything patentable that
somebody hasn't done already.

I've done it a bunch of times, including boosters that transitioned
from discontinuous to continuous as the load increased. I've met
people who were horrified of continuous-mode boost; don't know why
they were. It's really nice and clean and doesn't need snubbing. Just
avoid the singularity.

[Ian Field]

"John Larkin" <jjla...@highNOTlandTHIStechnologyPART.com> wrote in message

news:ajg7k7ha1jh779rjp...@4ax.com...

Stop - you'll confuse the poor little mite.

[Ian Field]

"Jim Thompson" <To-Email-Use-Th...@On-My-Web-Site.com> wrote in

message news:qsc7k7ps9drmj5ecu...@4ax.com...

> On Tue, 21 Feb 2012 00:45:00 -0500, "Tom Del Rosso"
> <td...@verizon.net.invalid> wrote:
>
>>
>>Jim Thompson wrote:
>>> On Sun, 19 Feb 2012 20:34:28 -0500, "Tom Del Rosso"
>>> <td...@verizon.net.invalid> wrote:
>>>
>>> >
>>> > Jim Thompson wrote:
>>> > >
>>> > > PWM BOOST is NOT trivial, though I'm well on my way to an
>>> > > off-the-wall STABLE solution... found by running the math instead
>>> > > of my mouth.
>>> >
>>> > Off the wall in what way?
>>>
>>> In ways I will apply for patent, then explain ;-)
>>
>>So it's totally wacky then.
>>
>>:)
>
> Of course. That's my specialty... be different :-)
>
> ...Jim Thompson

Some would say; "special".

[Tom Del Rosso]

John Larkin wrote:
> Just avoid the singularity.

Avoiding black holes goes without saying.