"John Larkin" wrote in message
...
On Wed, 28 Mar 2007 16:22:40 GMT, "Genome"
wrote:


"John Larkin" wrote in
message
. ..
On Wed, 28 Mar 2007 13:17:32 GMT, "Genome"
wrote:


"Fred Bartoli"
fred._canxxxel_this_bartoli@RemoveThatAlso_fr ee.fr_AndThisToo wrote in
message ...
Genome a écrit :
"Fred Bartoli"
r_AndThisToo wrote
in
message ...
Would you post the .asc file so that I don't have to redo it all?


--
Thanks,
Fred.

Here you go.....

I can't tell you what I am trying to do because Jim has just got out
of
bed
in IC design mode (?).

The last one might do what I am looking for but I have to crap about
with
things for longer to find out other stuff.

Honest, don't waste too much time on it. I'm not going to pay (much)
attention.


Here it is.
As I don't know what you're trying to do (well I have a bit of idea,
but
since you don't want to tell :-) this is probably not ideal and you
probably can simplify things a bit, but you get the idea.


--
Thanks,
Fred.


It's good of you to have a play with things. I'll have to study that lot
for
quite a while, there's probably some tricks I should be using. I'm
having
a
go at simplifying what I've got.

It's meant to be the multiplier/divider circuit for a power factor
correction circuit.

The output of the voltage error amplifier, ideally, should be multiplied
by
a value proportional to the rectified line voltage and divided by the
square
of the average line voltage. The output of the multiplier goes to the
current error amplifier which controls line current.

Proportional to the rectified line voltage makes the current drawn
follow
the voltage, giving a resistive load.

Divided by the square of the average line voltage 'normalises'(?) the
power
circuit gain. If the rectified line doubles then the current draw should
be
halved and then you have to halve it again because the rectified line
voltage used for the first multiplication doubled as well.......

I'm doing this because I'm almost, sometime, never, going to get around
to
implementing a semi discrete PFC circuit and none of what is available
as
an
IC really does the job I think I want to do and I've just got bored with
them.

Thanks for looking but your time might be better spent on other things
since
I'm prone to ignoring advice and generally just beat my head against
stuff.
Mind you some of this might filter into my head.

If I come up with something I'll post it....

DNA



This sort of design, like most everything else, is eventually going
digital. Some crap 75 cent uP with on-chip mux'd ADC could run a tight
loop doing nothing but this algorithm maybe 20,000 times a second and
output PWM directly. It could do all sorts of rampup, duty-cycle
limiting, feedforward tricks, current sensing, loop compensation...
there's no limit. It's almost tragic.

John



.........

You are probably not wrong.....

It depends on how much people are prepared to dumb down the specs to cope
with the new age of dumbness. Who am I to speak? I'd be tempted to have a
bash myself (thought about it) but then again I wouldn't.....

Hmmmmm, there is going to be some sort of division of labour involved in
such a solution. Can we talk synergy? No, beyond some final year thesis, I
don't think it's going to happen.......

One day PID control will rule the world....... bummer.

DNA


Digital power supplies are the future...

http://powerelectronics.com/digital_power/


But it's 100x easier for a power supply designer to learn to program
than it is for a programmer to understand power supplies. Well, maybe
1000x.


John



Mumble. All you need is a TCP gargle stack and you are set to download the
latest malicious siftware removal tool.

Interesting point though..... although I would have problims explaining why.

DNA