Isolated, regulated, toroidal step down transformer AC power supply design.

[swanny]

I don't think it could be rightly described as a "charge pump" device at
all.

Apparently (because I had to look it up) Charge Pump devices work by
electronically switching the polarity of the capacitors. IE "the capacitor
is disconnected from the original charging voltage and reconnected with its
negative terminal to the original positive charging voltage".

That doesn't happen at all within my application.

I think that the schematic I am looking at is rightly described as a voltage
multiplier.

I.E. it is an "electrical circuit that converts AC electrical power from a
lower voltage to a higher DC voltage by means of capacitors and diodes
combined into a network."

In particular it is a half-wave series multiplier, where the voltage is only
doubled once.

However, voltage multipliers "can be used to generate bias voltages of a few
volts or tens of volts or MILLIONS OF VOLTS"

I've not seen this method described used to generate a bipolar supply from a
single AC source before. Do you have a schematic or photo of the PCB that would
allow further examination?

 

[jasen]

With great difficulty.

However, it is a problem with the thread structure of most readers, not with
the order of my statements.

does that make sense to you?

 

[Bob Parker]

does that make sense to you?

It's the same 'Mark logic' which has applied to all his other postings.

It makes sense to him but not us. :-(

 

[jasen]

That's not what you have got. It's what you think you have got.
You have 30VDC out (+/-15VDC).

You have a wall wart transformer with poor load regulation. I'm guessing it's
about 15VAC you have coming out of your wall wart. I also suspect the original
design is relying on this to work.

Try taking some measurements rather than quoting the info that's printed on it.

Mark said he had 4 diodes in the rectifier, that's not a normal doubler.
or rather that's two doublers one going up and one going down.

Bye.
Jasen

 

[jasen]

What was wrong with either of these suggestions?

a) Buy another UPS (on Ebay for around $30) and then just step-down the
voltage using my pre-existing wall-wart transformer. If 240 VAC goes in,
something CLOSE to 9 VAC should come out and everything is happy, ..maybe.

good luck finding an online, sine wave, UPS for that price.

A $30 UPS is likely to be modified square wave, and offline, and it'll be
exactly useless for your purpose.

Bye.
Jasen

 

[Bob Parker]

good luck finding an online, sine wave, UPS for that price.

A $30 UPS is likely to be modified square wave, and offline, and it'll be
exactly useless for your purpose.

Bye.
Jasen

I thought of telling him that, but I knew he'd disagree because it
wasn't what he wanted to hear, so I didn't.

Bob

 

[Mark]

Which description method would that be? "Charge Pump" or "Voltage
Multipliers".

These devices are commonly classed as Voltage Multipliers.

The specific voltage multiplier I am looking at is a Half-wave Voltage
Doubler, or more accurately, two of them.

Here is a schematic of a "Half-wave Voltage Doubler"
http://tpub.com/neets/book7/0294.GIF

Here is the general description of Voltage Multipliers from the Electrical
Engineering Training series: http://tpub.com/neets/book7/27m.htm

My device is not like the "Full-wave voltage doubler" described in Fig 4-49
because it produces two output voltages (+/- 15VDC). So two halves do not
make a whole, in this case.

It is TWO Half-wave Voltage Doublers. I have Emailed the schematic to
[email protected] in pdf format. I can't think of any easy way to
publish it here. Enjoy the Spam.

p.s. What does a wolf in sheep's clothing do over the Easter break?

 

[Mark]

Correct. It is two Half-wave Voltage Doublers.

Mark said he had 4 diodes in the rectifier, that's not a normal doubler.
or rather that's two doublers one going up and one going down.

Bye.
Jasen

 

[Brian g]

"Mark" [email protected] wrote


Which description method would that be? "Charge Pump" or "Voltage
Multipliers".

These devices are commonly classed as Voltage Multipliers.




****Please go away you mindless cretin of a troll,just go far far away.
Anywhere but here,just go away!!


Brian G

 

[Mark]

Circuits described as "Charge Pump" typically use on/off SWITCHES to switch
the polarity of the capacitors.

For example, see:
http://www.eecg.utoronto.ca/~kphang/ece1371/chargepumps.pdf

I.E. The Cockcroft and Walton "Charge Pump" takes in as input a DC voltage
and "Charge Pumps" it to a higher DC voltage by disconnecting the capacitor
from the original charging voltage and RECONNECTING its NEGATIVE terminal to
the original POSITIVE charging voltage".

Circuits described as "Voltage Multipliers" (or "Voltage Doubler" in this
specific case) is an electrical circuit that converts AC electrical power
from a lower voltage to a higher DC voltage by means of capacitors and
diodes combined into a network. They DO NOT USE switches.

For example see: http://tpub.com/neets/book7/27m.htm The Diodes OPERATE AS
self-timed switches...but they are NOT switches per se.

NOW WHO IS IT THAT DOES NOT KNOW THEIR AC FROM THEIR DC?

...and THAT'S TWICE you've made the same mistake.

But wait, there is more!

To quote an authorities book on the subject, see:

http://www.edacafe.com/books/McGraw_Hill/Charge_Pump_Circuit_Design/45xch01.pdf)

"In order to overcome the aforementioned limitations, John F. Dickson
proposed a VOLTAGE MULTIPLIER circuit [as opposed to the Cockcroft-Walton
VOLTAGE MULTIPLIER circuit] However, the nodes of the diode chain are
coupled to the inputs via capacitors in PARALLEL(Dickson), instead of in
SERIES(Cockcroft-Walton)".

My device has its capacitors coupled to the inputs via capacitors in
PARALLEL as per Dickson.

My device is not the classic Cockcroft and Walton "Charge Pump" OR the
classic Cockcroft and Walton "Voltage Multiplier" which uses a diode chain
coupled to the inputs via capacitors in SERIES.

So, the "Dickson Charge Pump" which does NOT use switches to switch the
polarity of the capacitors OR use capacitors in series, is in fact a
"Voltage Multiplier"[1].

[1] The term "Voltage Multiplier" may not have been in common use when
Dickson invented his "Charge Pump", so he deferred to the Cockcroft and
Walton terminology.

 

[Mark]

Enjoy the spam, ****. [email protected] You started this.

 

[Brian g]

"Mark" [email protected] wrote


You started this.

****Please go away you mindless cretin of a troll,just go far far away.
Anywhere but here,just go away!!


Brian G

****** Er,I started this??????????

You are the mindless troll that asked the first bog ignorant question!

Wotta wanker!
Brian g.

 

[Mark]

Hard fucking luck.

Usenet is NOT my life and I won't be here for long, but I ain't going
anywhere based on the ORDER of some sniffling little toady boy.

 

[Mark]

Does 'Pussy' want some milk?

Get back under your bridge, clueless troll.

 

[Bob Parker]

Hard fucking luck.

Usenet is NOT my life and I won't be here for long, but I ain't going
anywhere based on the ORDER of some sniffling little toady boy.

Troll (Internet)
From Wikipedia, the free encyclopedia

"In Internet terminology, a troll is someone who intentionally posts
derogatory or otherwise inflammatory messages about sensitive topics in
an established online community such as an online discussion forum to
bait users into responding."



Get back under your bridge, troll.

 

[Bob Parker]

Does 'Pussy' want some milk?

Get back under your bridge, troll.

 

[Mark]

The plain ordinary sense of what I said and the truth of the matter are both
in my favour.

Internal topography makes no difference to the thread structure of Usenet
topics on most software 'Readers'. If there is such a 'Reader' that can
thread conversations based on the internal topography of individual
messages, I've yet to see it.

Therefore, the topography I choose makes absolutely no difference to the
ORDER in which individual messages are read. However, the ORDER in which
the conversations are presented by the software 'Reader' are not necessarily
chronological.

This was what seemed to be confusing "Swanny", originally. When he retorted
"No it isn't." to my claim that I had already given the explanation he
requested about 1/2 dozen times in the same thread. I had. Possibly all the
explanations (which are still there) appear BELOW this point. IE. 'Reader'
software does not necessarily present statements in chronological order.

 

[Mark]

That will serve as an almost functionally perfect description of 'Das
Führer' of 'Phil-O-phile'.




...but I would have added a few adjectives like "embarrassingly wrong"

 

[Bob Parker]

That will serve as an almost functionally perfect description of 'Das
Führer' of 'Phil-O-phile'.


..but I would have added a few adjectives like "embarrassingly wrong"

Fool

 

[Mark]

Chase it Kittty ...chase it!

Troll (Internet)
From Wikipedia, the free encyclopedia

"In Internet terminology, a troll is someone who intentionally posts
derogatory or otherwise inflammatory messages about sensitive topics in an
established online community such as an online discussion forum to bait
users into responding."



Get back under your bridge, troll.