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design a special switch mode power supply

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kamalifard

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i want to design a power supply by this characteristic in output:

variable output from 0 to 2kv or above
low ripple at output only ± 10mv
positive and no constant currunt but little below 10mA

linear type is is huge heavy and expensive because of its transformer and it should be a multi stage switching type but can have a linear stage
this device supply from 220v AC 50Hz

tanks a lot
 
And you expect us to sit here and design the whole thing for you (even worse if it's a school assignment)? You're going to have to tell us what exactly it is you need help on.

By the way, 10mV ripple at 2kV output is 0.0005% ripple which is almost impossible (if not outright impossible) to get with current technology. It would be better if you specified your ripple as a percentage since it is over a range of voltages rather than at a fixed voltage.

You also say no constant current as a specification. Do you mean no current limiting? Or do you mean you do not need constant current? Becuase if this is what you mean then you need to review your understanding of power supplies. YOu describe what is a voltage supply, but then say you do not need constant current (which by definition cannot be part of a voltage supply). You always adjust the voltage to regulate the current, or adjust the current to regulate the voltage- you can't have both regulated voltage and current at the same time.

Linear type is not huge heavy and expensive because of the transformer. It's huge and heavy because the linear stage needs a giant heatsink. You only need 10mA of current so the transformer is going to be TINY. Just follow it with a switching stage instead of a linear stage. The transformer provides isolation from the AC line which also makes it a lot safer.
 
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hello

i want only general guide no totlal design one say me you shoud use active & digital filter

its apllication is determined in a no related to electronic field and i cant explain esily i see linear type myself and and it have in inside atrance & a autotrance and a high voltage shield and it was true that i typed becaus transe worked at 50 Hz and total cost of elements was about 5000 us$ here
 
hello

i want only general guide no totlal design one say me you shoud use active & digital filter

its apllication is determined in a no related to electronic field and i cant explain esily i see linear type myself and and it have in inside atrance & a autotrance and a high voltage shield and it was true that i typed becaus transe worked at 50 Hz and total cost of elements was about 5000 us$ here

Digital filters and active filters do not apply for power supplies. They only apply for signals. I would use a transformer to isolate the voltage and also use it to maybe step down or step-up. But your voltage range goes to very low below main AC voltage and so high above it, you might want to keep it the same. Your voltage range is so wide that I do not think it is possible to build a single supply that can cover that entire range. You might have to end up building multiple supplies to cover a small segment of voltage range (and connecting them so they pass the output between themselves depending on the selected output voltage).

Then you need a rectifier and smoothing capacitor (at least those components) to turn the AC after the transformer (or directly from AC main voltage if you use no transformer) to DC. THen use a switching regulator to take DC and step-it up or down, and to regulate it.

Another way is to use a variable transformer to step-up or down the voltage when it is in AC since this is much easier to do in AC than DC. Then rectify the AC voltage and regulate it. BUt the transformer will be expensive since it is variable. However, it is very easy to step up or down an AC voltage a very large amount with a transformer than with a DC switching regulator.
 
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If (and a big one) he can pull it of, my guess would be it's gonna be one hell of a big...... thing.
Sounds like multiple transformers "maybe", then some serious caps, real serious.

What the hell would you want to do with that!
(Sorry I did not understand your second post.)
 
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