Need the topology for a current to current SMPS, not voltage tovoltage SMPS

[RobertMacy]

I raise you one: I have a megacycle meter

This one:

http://www.ohio.edu/people/postr/bapix/Dip_59.htm

That's too bad you won't be able to use it, since it measures megacycles
and megacycles no longer exist. Unless you can find some equipment that
produces megacycles, like...perhaps I can help, I have an original pair of
WWII walkietalkies!

You have NO idea how long it took me to stop saying megacycles/kilocycles
and start saying megaHertz/kiloHertz.

 

[Joerg]

That's too bad you won't be able to use it, since it measures megacycles
and megacycles no longer exist. Unless you can find some equipment that
produces megacycles, like...perhaps I can help, I have an original pair
of WWII walkietalkies!

I stopped keeping such stuff after moving to California, where houses
neither have basements nor attics.

You have NO idea how long it took me to stop saying
megacycles/kilocycles and start saying megaHertz/kiloHertz.

You can be lucky not to have gone to school in Europe. There, the
bureaucrats change units at a whim. First we learned kilopond, then that
went out of fashion and Newton was en vogue. Even worse with pressure:
Torr, then it was changed to atmospheres, then it was change to bar,
then it was changed to Pascal. Crazy.

Now that I moved to the US and workd in some fields such as aerospace
where metric isn't used I became used to imperial units. Not as easy in
the math but the nice thing is that the units never change.

 

[Joerg]

[...]

Grin.. sure... the ascii is a current boost and the first dropbox
scribble is a current buck. I'm not sure what you mean about the
ascii drawing... It's being fed from a current source.. so how can
it be a 'standard buck'. (The output is also a (DC) current.. so I
can't really put a capacitor there.)

I don't really care about the source. It's max voltage is specified at
100V, no? It' max (and constant) current is specified at .05A, no?

There is therefore a maximum power output capability of 5W. No?

I think the easiest way for the large compliance range is a flyback that
measures the input current and regulated to an output current of desired
(or programmable) magnitude in relation to the measured input current.
Then it's input voltage will automatically adjust to what is needed,
without wasting anything other than the losses in the flyback. Of
course, the 95% requirement pretty much mandates a recuperating winding
so it'll be a custom transformer. No flaring off of the leakage
inductance spikes in snubbers or zeners.

It does not matter what topology you use, you cannot get more out than
you put in. Where am I wrong here?

Washington "gets" about 50% more out than what comes in :-(

[...]

 

[Joerg]

Ah, yes! Into every forest of test equipment, a little acorn (tube)
must fall!

This really is an excellent piece of "kit". A few years ago I did a
comparison of my Model 59, a Heathkit dipper, and the dipper coil
accessory set for an MFJ 269 impedance meter.

The test fixture was a piece of Airdux coil, with an air variable
capacitor soldered across the ends. Should have a nice high Q.

The MFJ-and-probe combination was... well, saying "pathetic" and "an
absolute waste of money and effort" is about right. In order to get
any readable dip in the meter I had to shove the probe to within a
small fraction of an inch of the Airdux coil. Talk about a
measurement, affecting the thing to be measured :-(

The Heathkit solid-state dipper did better. I could get a good
reading by just barely bringing the coil to the center end of the
Airdux... wouldn't have been much capacitive coupling to worry about.

The Measurements 59 - wow. Nice sharp high-Q narrow dip with the
coil about 2" away from the center of the Airdux.

In them days people still knew how it's done. I bet it is possible to
copy a Model 59 using semiconductors, such as dual-gate FETs. But there
is no market. Most kids these days don't have a clue what a dipmeter is.
In fact, whenever I showed up with my Heathkit 1250 the only folks who
knew what that weird thang was were ham radio operators well past the
age of 50.

The best combination would probably be the 59 as a dipper, and the MJF
in frequency-counter mode to give a more precise reading on the dip
frequency, just as the article you pointed to suggests.

Nowadays you can easily achieve that precision: Use the Model 59 and run
the spectrum analyzer in parallel, using a loop antenna underneath your
work bench. Make it snap to the strongest signal. BTDT. Now, about
changing the display of the spectrum analyzer to megacycles ...

 

[Phil Hobbs]

That's too bad you won't be able to use it, since it measures megacycles
and megacycles no longer exist. Unless you can find some equipment that
produces megacycles, like...perhaps I can help, I have an original pair
of WWII walkietalkies!

You have NO idea how long it took me to stop saying
megacycles/kilocycles and start saying megaHertz/kiloHertz.

I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is
100 fA FS). Not to be too pico, er, picky.

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

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

 

[Joerg]

I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is
100 fA FS). Not to be too pico, er, picky.

I can raise you one more. Here is an "entertainment system" we have at
the entrance:

http://www.electricstuff.co.uk/3nfset.jpg

It essentially contains the first IC in the world. The tube contains
three sections, four resistors and two capacitors (it's all inside the
glass). IIRC my grandpa bought it in 1927. He was always the early
adopter when it came to technology.

 

[Phil Hobbs]

I can raise you one more. Here is an "entertainment system" we have at
the entrance:

http://www.electricstuff.co.uk/3nfset.jpg

It essentially contains the first IC in the world. The tube contains
three sections, four resistors and two capacitors (it's all inside the
glass). IIRC my grandpa bought it in 1927. He was always the early
adopter when it came to technology.

Wow. I guess the Blaupunkt/VW approach to product obsolescence started
early--filament blows, replace the whole radio.

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

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

 

[Spehro Pefhany]

I also have a Keithley 405 "Micro-Microammeter" (most sensitive range is
100 fA FS). Not to be too pico, er, picky.

Cheers

Phil Hobbs

I can remember caps (probably out of obsolete equipment at the time)
being marked in MMF.

I ran across an old design for an optical lever amplifier that used
OC71 transistors. Had the misfortune to come into about 1,000 of those
things as a wee lad. They almost put me off semiconductors.

https://sites.google.com/site/transistorhistory/Home/european-semiconductor-manufacturers/philips

25mW maximum Pd (confused me when I ran into some hydrogen thyratons
that were 40MW)

-5V maximum Vce (minus plate voltage, what insanity is that?

Beta of 50, not great, but not terrible.

IIRC, leakage was horrible, uA at room temperature, and rapidly
increasing if you approached that 25mW maximum Pd.

 

[Joerg]

I can remember caps (probably out of obsolete equipment at the time)
being marked in MMF.

Then you aren't old enough. Our forefathers measured capacitance in
jars. Later in centimeters.

I ran across an old design for an optical lever amplifier that used
OC71 transistors. Had the misfortune to come into about 1,000 of those
things as a wee lad. They almost put me off semiconductors.

They actually brought me to semiconductors. I got a bag of hearing aid
size OC transistors of dubious quality, brand name "Fell-of-a-truck".
Some leaked terribly, others had other blemishes, but it cost only the
equivalent of a couple of Dollars for dozens. Now I could build stuff
that ran on a totally exhausted flashlight battery. In Europe they were
called "Lady Cells" for some reason, had 3V when fresh, were used to
power flashlights. Once under 2V they were discarded, as in "free". I
could use them to below 1V with my transistor stuff. Same with depleted
D-cells. That would not have worked with Si-transistors (it didn't, I
tried later).

One of my "innocent" teenage projects was to copy the idea of a bug from
some spy movie. I placed it in a flower pot and then could hear my
parents talk upstairs in the living room, on longwave (AFAIK only
available on radios in Europe). Just for fun, to see if I could pull
that off. Later after heading off to university I confessed.

https://sites.google.com/site/transistorhistory/Home/european-semiconductor-manufacturers/philips

25mW maximum Pd (confused me when I ran into some hydrogen thyratons
that were 40MW)

-5V maximum Vce (minus plate voltage, what insanity is that?

Didn't the OC71 do 20V Vce?

Beta of 50, not great, but not terrible.

IIRC, leakage was horrible, uA at room temperature, and rapidly
increasing if you approached that 25mW maximum Pd.

Yeah, they all leaked like a sieve. But since one could make circuits
that ran at less than a volt one only had to convince family and
neighborhood to chuck depleted batteries in this here box instead of the
garbage can.

Oh, and if you scraped the paint off the glass you could make a nice
photo sensor. Try that with contemporary transistors.

 

[[email protected]]

Me too! I paint in a long sleeved Oxford shirt! even in AZ

I have a closet full with paint all over them. ;-)

My wife is still laughing about the time, on one of our sojourns including
Santa Cruz Boardwalk; I went to get us hotdogs from the boardwalk vendors
in a three piece suit, ...and was carrying my briefcase.

I only wear a suit for funerals, weddings, and the occasional customer
trip. In the last 30 years, the first two happened once or so a year
and the latter never. Had a couple customer visits (execs, even) last
month, though. Seems many more to come.

In 70's while at Stanford's Chapel for Christmas obaservance, one of my
colleagues wearing a rather worn sweatsuit [it WAS post hippy era] leaned
over and in attempting to ridicule my dress suit asked, "Why do you want
to dress like everyone else?" My reply, "Look around. I'm the ONLY suit
here. Look at you. Why do YOU want to dress like everyone else." And, yes.
EVERYBODY else was in totally casual attire.

;-)

 

[[email protected]]

[email protected] wrote:
[email protected] wrote:

[...]

I work for numerous clients who are all in very different
markets. This keeps our jobs interesting. But after talking to
automotive designers I'd be bored stiff if I had to do their job for
more than a year.
Perhaps but I think you have a pretty small view of that world.
Nope. Medical devices for hospitals, low cost medical devices for
consumers (over-the-counter), aircraft electronics, spacecraft stuff,
chemical pump controllers, power generation, oil/gas exploration
electronics, NDT, commercial automotive (trucks), and so on.
You have a very small view of the automotive market. That is for
sure.

I see it from two view points. One is the actual product and that often
doesn't look very good, both from a quality point of view and sometimes
also from an engineering point of view (flickering LED backlights
anyone?). Then from a people perspective and here talking to folks who
actually work in that field helps. Pretty much all of them reported
extreme pressure to keep NRE and R&D schedules down, which explains a
lot of the quality issues. To the point I wouldn't want to work there.
As a consultant maybe but niot if they'd demansd unrealistic timelines
like they often do from their employees.

Cost is everything but it's still no excuse for designing junk. ...

Nobody seems to have told the executives that are ultimately responsible
for automotive electronics. Nearly all quality issues have their root
cause in upper management.

I'm with you there. "The last penny got shaved a
buck-and-a-half-ago."

Except I do not cut corners. Ever. If a client wants me to do that I
politely decline the whole assignment. It does happen but very rarely,
and those companies then do not even become clients of mine.

I don't but I have never been told to, either.

That's what Maxim kept telling people

Touché. The difference is Maxim keeps proving that while things
change, management doesn't.

I am just the opposite. I wear shorts and T-shirts as long as I can.
Only in really cold weather it's lumberjack shirts and jeans. For a
winter coat or jacket it almost would have to drop to below 0F.

Sure, I wear shorts[*] around the house, with Oxfords. I just can't
stand wearing T-shirts or even short-sleeved shirts. Spent a week at
the beach in September in swim trunks and oxford shirt. ;-)

[*]Though, with Global Warming, I've already put the shorts up for the
Winter.

 

[Spehro Pefhany]

Yeah, they all leaked like a sieve. But since one could make circuits
that ran at less than a volt one only had to convince family and
neighborhood to chuck depleted batteries in this here box instead of the
garbage can.

I think I could make a FF toggle at about 100kHz. A bit more if it was
clamped to prevent saturation. ft was only a few hundred kHz.

Oh, and if you scraped the paint off the glass you could make a nice
photo sensor. Try that with contemporary transistors.

Yup, metal-sleeved or painted glass case filled with grease.


Best regards,
Spehro Pefhany

 

[Joerg]

[...]

That's what Maxim kept telling people

Touché. The difference is Maxim keeps proving that while things
change, management doesn't.

There was another guy who promised change. Actually hope and change. I
never saw the hope part and he made a royal mess.

I am just the opposite. I wear shorts and T-shirts as long as I can.
Only in really cold weather it's lumberjack shirts and jeans. For a
winter coat or jacket it almost would have to drop to below 0F.

Sure, I wear shorts[*] around the house, with Oxfords. I just can't
stand wearing T-shirts or even short-sleeved shirts. Spent a week at
the beach in September in swim trunks and oxford shirt. ;-)

Yikes. That is something I find odd. However, in places like Singapore
people even wear shorts with dress shirts and ties. But short sleeves.

[*]Though, with Global Warming, I've already put the shorts up for the
Winter.

We have stashed the usual record amount of firewood for winter again. I
want my fair share of this global warming <stomp, stomp>!

 

[[email protected]]

[email protected] wrote:

[...]

There are automotive electronics that work quite well, mostly in
Japanese cars. In the end it boils down to the reliability ratings of
the various entities in the know.
Things change. A lot!

That's what Maxim kept telling people

Touché. The difference is Maxim keeps proving that while things
change, management doesn't.

There was another guy who promised change. Actually hope and change. I
never saw the hope part and he made a royal mess.

Sign up for Obamacare yet? ;-)

However, I've been involved in many different markets at many
different levels, over the years. It's a *big* field. There is no
reason to do the same thing for forty years. Impossible, actually.

Not impossible. I met people who worked in one particular field such as
engine control units for over 30 years. I'd have a hard time doing that,
after being a consultant for this long.
ECUs have changed more than a little in 30 years. They will change
drastically, again, over the next ten. ...
Sure, incremental change. Same in medical ultrasound which is my home
turf. But ... after we built a flagship product in the late 80's and the
satellite R&D location was closed afterwards I wasn't too unhappy that I
could jump into consulting for the first time, and do something else.


... Hell, you'd have a hard time
showing up for work with your pants on, after being a consultant that
long. ;-)
As a consultant I get to wear shorts all summer long. When a web
conference with bigshots is coming up I have a "dress shirt on duty"
hanging in the lab closet
In my last job I was the only one who wore long pants from April to
October. Everyone else in Engineering wore T-shirts year 'round. I
can't do that. I wear long-sleeved shirts (Oxfords, preferred) even
for mowing the lawn.

I am just the opposite. I wear shorts and T-shirts as long as I can.
Only in really cold weather it's lumberjack shirts and jeans. For a
winter coat or jacket it almost would have to drop to below 0F.

Sure, I wear shorts[*] around the house, with Oxfords. I just can't
stand wearing T-shirts or even short-sleeved shirts. Spent a week at
the beach in September in swim trunks and oxford shirt. ;-)

Yikes. That is something I find odd. However, in places like Singapore
people even wear shorts with dress shirts and ties. But short sleeves.

I didn't get burned. ;-)

Haven't owned a short-sleeved shirt in at least 45 years (maybe in
high school - before I bought my own clothes).

[*]Though, with Global Warming, I've already put the shorts up for the
Winter.

We have stashed the usual record amount of firewood for winter again. I
want my fair share of this global warming <stomp, stomp>!

Didn't mean to get you excited. ;-)

 

[Joerg]

I think I could make a FF toggle at about 100kHz. A bit more if it was
clamped to prevent saturation. ft was only a few hundred kHz.

IIRC the OC71 had 1MHz ft. But the good stuff came soon after: The
AF139. That one was usable up to the UHF band, which it was designed for.

Yup, metal-sleeved or painted glass case filled with grease.

Some transistors didn't have grease in them, those were really useful as
photo receivers.

 

[Ralph Barone]

OK... We haven't done many AC circuit yet.. but I'm guessing the same
sort of thing can be done.
For completeness here's the way a current source buck-boost should look.

https://www.dropbox.com/s/eey79dkci1sqpp0/DSCF0034.JPG
(I figured out in the shower that the capacitor was in wrong.)

George H.

I suspect the hot shower might be one of the most useful design tools known
to man.

 

[Jasen Betts]

No matter what you do, you will never get more current out of the
circuit than the amount of peak current in the inductor at the moment
your FET switch opens.

but I do get more current out of the capacitor at the time the switch
opens than goes into the circuit

eg:

Version 4
SHEET 1 880 680
WIRE 32 64 -80 64
WIRE 64 64 32 64
WIRE 192 64 160 64
WIRE 256 64 192 64
WIRE 368 64 320 64
WIRE -80 80 -80 64
WIRE 192 96 192 64
WIRE 32 112 32 64
WIRE 368 112 368 64
WIRE 112 144 112 128
WIRE -80 240 -80 160
WIRE 32 240 32 176
WIRE 32 240 -80 240
WIRE 112 240 112 224
WIRE 112 240 32 240
WIRE 192 240 192 176
WIRE 192 240 112 240
WIRE 368 240 368 192
WIRE 368 240 192 240
WIRE -80 256 -80 240
FLAG -80 256 0
SYMBOL ind 208 192 R180
WINDOW 0 -18 84 Left 2
WINDOW 3 -34 24 Left 2
SYMATTR InstName L1
SYMATTR Value 10m
SYMBOL cap 16 112 R0
SYMATTR InstName C1
SYMATTR Value 100n
SYMBOL diode 256 80 R270
WINDOW 0 32 32 VTop 2
WINDOW 3 0 32 VBottom 2
SYMATTR InstName D1
SYMBOL npn 160 128 M270
WINDOW 0 79 32 Left 2
SYMATTR InstName Q1
SYMBOL current -80 80 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName I1
SYMATTR Value 50m
SYMBOL current 112 224 R180
WINDOW 0 -25 91 Left 2
WINDOW 3 -274 -46 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName I2
SYMATTR Value PULSE(5m 0 0 10n 10n 80u 100u)
SYMBOL res 352 96 R0
SYMATTR InstName load
SYMATTR Value 50r
TEXT -114 290 Left 2 !.tran 2s

 

[Jasen Betts]

That's probably because your input is a current source and you waited
too long to close the switch.

indeed, ltspice loosk for a steady state. anything above 0ps is too
long.

 

[Phil Hobbs]

I can remember caps (probably out of obsolete equipment at the time)
being marked in MMF.

I ran across an old design for an optical lever amplifier that used
OC71 transistors. Had the misfortune to come into about 1,000 of those
things as a wee lad. They almost put me off semiconductors.

https://sites.google.com/site/transistorhistory/Home/european-semiconductor-manufacturers/philips

25mW maximum Pd (confused me when I ran into some hydrogen thyratons
that were 40MW)

-5V maximum Vce (minus plate voltage, what insanity is that?

Beta of 50, not great, but not terrible.

IIRC, leakage was horrible, uA at room temperature, and rapidly
increasing if you approached that 25mW maximum Pd.

When Keithley started using FETs instead of tubes in their
electrometers, their most sensitive range went from 100 fA FS to 10 pA
FS, and stayed there for years and years. Of course my 405 needs a
couple of hours' warm-up before that scale is usable.

BTW there's a Megacycle Meter on eBay for $40 at the moment.
http://tinyurl.com/k2v2xlo

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

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

 

[Joerg]

[email protected] wrote:
[...]

There are automotive electronics that work quite well, mostly in
Japanese cars. In the end it boils down to the reliability ratings of
the various entities in the know.
Things change. A lot!

That's what Maxim kept telling people
Touché. The difference is Maxim keeps proving that while things
change, management doesn't.

There was another guy who promised change. Actually hope and change. I
never saw the hope part and he made a royal mess.

Sign up for Obamacare yet? ;-)

Nope. It would be 1.5x the price of our current plan.

However, I've been involved in many different markets at many
different levels, over the years. It's a *big* field. There is no
reason to do the same thing for forty years. Impossible, actually.

Not impossible. I met people who worked in one particular field such as
engine control units for over 30 years. I'd have a hard time doing that,
after being a consultant for this long.
ECUs have changed more than a little in 30 years. They will change
drastically, again, over the next ten. ...
Sure, incremental change. Same in medical ultrasound which is my home
turf. But ... after we built a flagship product in the late 80's and the
satellite R&D location was closed afterwards I wasn't too unhappy that I
could jump into consulting for the first time, and do something else.


... Hell, you'd have a hard time
showing up for work with your pants on, after being a consultant that
long. ;-)
As a consultant I get to wear shorts all summer long. When a web
conference with bigshots is coming up I have a "dress shirt on duty"
hanging in the lab closet
In my last job I was the only one who wore long pants from April to
October. Everyone else in Engineering wore T-shirts year 'round. I
can't do that. I wear long-sleeved shirts (Oxfords, preferred) even
for mowing the lawn.
I am just the opposite. I wear shorts and T-shirts as long as I can.
Only in really cold weather it's lumberjack shirts and jeans. For a
winter coat or jacket it almost would have to drop to below 0F.
Sure, I wear shorts[*] around the house, with Oxfords. I just can't
stand wearing T-shirts or even short-sleeved shirts. Spent a week at
the beach in September in swim trunks and oxford shirt. ;-)

Yikes. That is something I find odd. However, in places like Singapore
people even wear shorts with dress shirts and ties. But short sleeves.

I didn't get burned. ;-)

Haven't owned a short-sleeved shirt in at least 45 years (maybe in
high school - before I bought my own clothes).

My Oxfords are only for business and church, and there usually for
memorial services. On Sundays I go in a Hawaiian short sleeve shirts
even when I am ushering.

[*]Though, with Global Warming, I've already put the shorts up for the
Winter.

We have stashed the usual record amount of firewood for winter again. I
want my fair share of this global warming <stomp, stomp>!

Didn't mean to get you excited. ;-)

Well, the leftists make us pay taxes for it so I want some