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Re: Very high gain transformerless boost converter - is it possible
On Tuesday, 4 September 2018 17:35:41 UTC+1, John Larkin  wrote:
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I'm sure it's zero, +/- not very much.


NT

Re: Very high gain transformerless boost converter - is it possible
On Tuesday, September 4, 2018 at 6:19:29 PM UTC-4, snipped-for-privacy@gmail.com wrote:
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Huh, I have no idea, but I'd bet (a beverage) it's better than 1%.  

George H.  
I took data at an FEL that used a big ass Van de Graff to  
accelerate the electrons.
  

Re: Very high gain transformerless boost converter - is it possible
On Wednesday, 5 September 2018 01:09:41 UTC+1, George Herold  wrote:
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If I were really going to place a bet I'd take you on. I daresay there's a fair difference between the latest higher-tech van de graaf and something from their heyday.


NT

Re: Very high gain transformerless boost converter - is it possible
On Tuesday, September 4, 2018 at 10:19:28 PM UTC-4, snipped-for-privacy@gmail.com wrote:
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Right, (I figure I owe most people here a six pack of 'beverages'  
already so another hardly matters.)  But I was thinking of a lower  
cost 'toy' Van der Graff, like is used in physics demo's.  
I could ask some of the physics 'lab guys' to try and measure one.  
Heck, someone might have already done it.  

George H.  
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Re: Very high gain transformerless boost converter - is it possible
On Wednesday, 5 September 2018 13:15:20 UTC+1, George Herold  wrote:
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even a toy one is going to take a couple of watts to run. Output what, a microamp? Maybe we'll see how wrong I am.


NT

Re: Very high gain transformerless boost converter - is it possible
On Tuesday, September 4, 2018 at 3:19:29 PM UTC-7, snipped-for-privacy@gmail.com wrote:
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The modern equivalent (pelletron) claims <http://www.pelletron.com/products/pelletron-charging-chains/
circa 100 uA and 25MV capability: that's about four horsepower, and I'd guess
the friction losses in the link-chain are very low indeed.  The whole system is basically
a motor, cogwheel, chain, and idler wheel at HV.

Re: Very high gain transformerless boost converter - is it possible
The best bet would be Dickson triplers stacked.  

The first one takes it to 36, the next one takes it to about 100, the next  
one takes it to just about 300. More like 290 I would say depending on the  
parameters you give the convertors. Can you get by on 290 ? If not then sta
ck another one on top but fed from the original 12 or maybe just a doubler  
off the 36. Caps will not be cheap because they need low ESR and high volta
ge rating.  

I would not attempt to multiply it all at once but am at a loss to explain  
exactly why. It just seems the current in the choppers would be too high fo
r good efficiency. Though more junctions means more drop, they are not as s
ignificant at higher voltages.  

For each stage of the convertor, you are talking 4 good power transistors,  
4 very good capacitors and 6 low loss diodes, Shottkies in the first stage  
at least. In the first stage you might try to find something like the 1N609
5, but those do lose at higher currents.  

One nice thing about using Dicksons is that the main output filter has very
 little to do because it is fed with 2 polarities of a square wave, and I m
ean a real square wave not some rounded spiked and "rung" out waveform.  

However the cost is ridiculous compared to just biting the bullet and using
 a transformer. Also with a transformer it can have isolated output.  

It is so much easier and cheaper just to go to Digikey and find a transform
er with a ~1:20 ratio, feed it with a totem pole at its resonant frequency  
and use a doubler on the output. Use a chopper before the main filter for r
egulation, or synchronous rectification if you can handle designing it. (mo
re efficient)

At 150 watts that will be a fairly good size transformer and will cost mone
y, but still cheaper than the stacked Dicksons. And much less designing, be
cause with the Dicksons each stage has to be different. Different outputs,  
different diodes and different caps, you must choose them all. With this ma
ny components you don't want too much overkill. With a transformer you desi
gn ONE circuit and call it a a day.  

Your call. I like to avoid transformers because they can become unavailable
. But sometimes you can't always get what you want.  

I just checked Digikey and no suitable transformer is readily available. Wi
nd your own. At the right frequency you only need a few turns in the primar
y. So 4 turns there and you want 80 turns on the secondary. For a one off i
t may be alot of work but handleable. For production forget it, the Chinese
 probably have something.

Re: Very high gain transformerless boost converter - is it possible
snipped-for-privacy@gmail.com wrote...
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 Do you have a few good references for the Dickson
 voltage multipliers?  I only found two recent
 locked Academic papers (used my Harvard access to
 get them).  No mention of why called Dickson, no
 paper by him, etc.  Looks like Cockcroft-Walton.


--  
 Thanks,
    - Win

Re: Very high gain transformerless boost converter - is it possible
tirsdag den 4. september 2018 kl. 00.23.05 UTC+2 skrev Winfield Hill:
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https://en.wikipedia.org/wiki/Voltage_multiplier#Dickson_charge_pump

;)



Re: Very high gain transformerless boost converter - is it possible
On Monday, September 3, 2018 at 5:32:13 PM UTC-5, Lasse Langwadt Christensen wrote:
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That's not what I designed.

Re: Very high gain transformerless boost converter - is it possible
snipped-for-privacy@gmail.com wrote...
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 Please give us a description.


--  
 Thanks,
    - Win

Re: Very high gain transformerless boost converter - is it possible
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What follows is an LT Spice representation of it. The drive sources are out
 of polarity of the same square wave. My circuit values were to get about 9
 or 10 amps at 36 volts. The caps are like 10,000 uF CGR or CGS quality, lo
w ESR and the diodes are Shottkeys. The transistors I was thinking of 2N588
3 and 5885 at the time.  

If 150 watts is desired, this circuit should supply about 200, after more c
onversions that should be enough for half decent regulation without much ad
o.

Version 4
SHEET 1 880 1208
WIRE 48 -288 -720 -288
WIRE 480 -96 -416 -96
WIRE -720 -64 -720 -208
WIRE -64 64 -224 64
WIRE 48 64 48 -288
WIRE 48 64 -64 64
WIRE 160 64 48 64
WIRE 336 64 160 64
WIRE -64 112 -64 64
WIRE 160 112 160 64
WIRE -544 224 -784 224
WIRE -288 224 -288 112
WIRE -288 224 -544 224
WIRE -224 224 -224 160
WIRE -64 224 -64 176
WIRE -64 224 -160 224
WIRE 160 224 160 176
WIRE 272 224 160 224
WIRE 336 224 336 160
WIRE 400 224 400 112
WIRE 480 224 480 -96
WIRE 480 224 400 224
WIRE 336 256 336 224
WIRE -224 272 -224 224
WIRE 400 304 400 224
WIRE -288 320 -288 224
WIRE -784 400 -784 304
WIRE -544 480 -544 224
WIRE 480 480 -544 480
WIRE 48 608 48 64
WIRE 48 608 -224 608
WIRE 336 608 48 608
WIRE -224 624 -224 608
WIRE -64 704 -64 224
WIRE 160 704 160 224
WIRE 160 768 160 752
WIRE -416 816 -416 -96
WIRE -416 816 -784 816
WIRE -288 816 -288 672
WIRE -288 816 -416 816
WIRE -224 816 -224 720
WIRE -64 816 -64 768
WIRE -64 816 -160 816
WIRE 160 816 160 768
WIRE 272 816 160 816
WIRE 336 816 336 704
WIRE 400 816 400 656
WIRE 480 816 480 480
WIRE 480 816 400 816
WIRE -64 880 -64 816
WIRE 160 880 160 816
WIRE -224 896 -224 816
WIRE 336 896 336 816
WIRE -288 944 -288 816
WIRE 400 944 400 816
WIRE -784 976 -784 896
WIRE -64 1200 -64 944
WIRE 160 1200 160 944
WIRE 160 1200 -64 1200
WIRE 864 1200 160 1200
FLAG -224 384 0
FLAG 336 368 0
FLAG -224 1008 0
FLAG 336 1008 0
FLAG -720 -48 0
FLAG -784 400 0
FLAG -784 976 0
SYMBOL npn 400 64 M0
SYMATTR InstName Q2
SYMBOL pnp 400 352 R180
SYMATTR InstName Q3
SYMBOL pnp -288 368 M180
SYMATTR InstName Q1
SYMBOL npn -288 64 R0
SYMATTR InstName Q4
SYMBOL npn -288 624 R0
SYMATTR InstName Q5
SYMBOL npn 400 608 M0
SYMATTR InstName Q6
SYMBOL pnp 400 992 R180
SYMATTR InstName Q7
SYMBOL pnp -288 992 M180
SYMATTR InstName Q8
SYMBOL cap -160 208 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C1
SYMBOL cap 336 208 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C2
SYMBOL cap -160 800 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C3
SYMBOL cap 336 800 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C4
SYMBOL diode -80 112 R0
SYMATTR InstName D1
SYMBOL diode 144 112 R0
SYMATTR InstName D2
SYMBOL diode 144 704 R0
SYMATTR InstName D3
SYMBOL diode -80 704 R0
SYMATTR InstName D4
SYMBOL diode 144 880 R0
SYMATTR InstName D5
SYMBOL diode -80 880 R0
SYMATTR InstName D6
SYMBOL voltage -720 -304 R0
SYMATTR InstName V1
SYMATTR Value V +12
SYMBOL voltage -784 208 R0
SYMATTR InstName V2
SYMATTR Value 0-12 SQUARE
SYMBOL voltage -784 800 R0
SYMATTR InstName V3
SYMATTR Value 12-0 SQUARE
TEXT 664 1168 Left 2 ;36 V OUTPUT

This circuit cascaded, rather than one main voltage multiplier, should be m
ore solid as far as regulation. Each multiplier in the stage would use diff
erent components chosen successively for more voltage and less current, wit

ginal 12 volts is tripled twice only a doubler is needed. If push pull oper
ation is maintained very little filtering will be needed.  

Originally for whatever reasons, I chose the transistors for their low Vces
at and the diodes were 1N6095 but I am sure better are available now. The c
ap values are overkill seemingly but that is done for the low ESR. Junction
 drops and ESR are the only things keeping the gizmo from 100 % efficiency  
because I chose a quite low frequency. It would run just fine at 100 Hz, at
 that speed you don't need high speed anything so switching time vanishes a
s a concern. No inductive load so no significant dv/dt.  

I believe it is the most efficient way to do it, if one wants 150 watts. St
ack those things up. Only the first stage is going to need any significant  
heatsinking or low Vcesat transistors or even Shottkeys, that inefficiency  
practically vanishes in the subsequent stages.  

Maybe just one multiplier and one output stage is better, if so, show me.

Re: Very high gain transformerless boost converter - is it possible
Note that I would not run it at 100 Hz, that is simply too low.  

Also this was for an amp in cars that would have the amp under the dash, re
member these were 1970s cars, a three wire cable would go out under the hoo
d to this unit and carry the square wave drive to it and bring back the 35  
volts. The way the transistor bases are connected, it would run underwater.
 Teh unit IS actually built, if I had hosting I would upload a picture. The
 only thing it lacks is the transistors.  

The amp was something else, knowing the assholes around I made it bulletpro
of. You could connect the speaker wires to the battery, or even into an AC  
outlet and all that would happen is the wires would burn off. If the unit w
as running at the time all that had to be done was to switch is off and bac
k on to reset it. The amp was BTL so it was better than 50 WPC. Total DC co
upled, clip proof and a set of tone controls that would put hair on your ch
est, curl it and take it off all in one fell swoop.  

We are talking late 1970sd here, this was unheard  of in a car back then. S
ure there were PA amps (like Bogen n shit) that had an output transformer a
nd would put out some power but they sounded like shit.

Re: Very high gain transformerless boost converter - is it possible
On 6.9.18 15:41, snipped-for-privacy@gmail.com wrote:
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There was a chance of working if you connected the lower collectors.

--  

-TV


Re: Very high gain transformerless boost converter - is it possible
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Don't those little arrows mean common ?  

Re: Very high gain transformerless boost converter - is it possible
On 6.9.18 20:19, snipped-for-privacy@gmail.com wrote:
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Are there wires between the collectors and the arrows?

--  

-TV


Re: Very high gain transformerless boost converter - is it possible
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Umm, actually no. If the heatsinks are grounded it is a simple matter to leave out the insulators, assuming a metal tab or as in the case of my little box the cases of TO-3 transistors.  

Re: Very high gain transformerless boost converter - is it possible
torsdag den 6. september 2018 kl. 14.41.10 UTC+2 skrev snipped-for-privacy@gmail.com:
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ut of polarity of the same square wave. My circuit values were to get about
 9 or 10 amps at 36 volts. The caps are like 10,000 uF CGR or CGS quality,  
low ESR and the diodes are Shottkeys. The transistors I was thinking of 2N5
883 and 5885 at the time.  
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 conversions that should be enough for half decent regulation without much  
ado.
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looks like two Dickson multipliers in parallel

Re: Very high gain transformerless boost converter - is it possible
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Somebody called it "a" Dickson convertor. I went with that. That came out of my head but like all the other things I invented I was not the first. (I got all of them with my DVD rewinder though)

Re: Very high gain transformerless boost converter - is it possible
snipped-for-privacy@googlegroups.com:

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Thanks.  Nice, descriptive article(s).

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