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Old 30th December 2005, 02:27 PM   #1
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Default PSU with Simple Source Follower Regulator

Hi,
attached is a simple but hopefully good (in relation to parts count) PSU that I plan to build. Only positve rail shown.

The quality of the attachment is bad (is there a fast&easy freeware circuit painter out there?), I hope you can read it.

My goal is to have a reasonable quiet and sonically well performing PSU, or the best what can be made out of that few components.

Is there something missing, any mistakes? What do you think of the ccs feeding the zeners (it's in fact cheaper than a current diode).

Rüdiger
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Old 30th December 2005, 02:54 PM   #2
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uh, oh: the Collector and the emitter of the BC560 are swapped...
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Old 30th December 2005, 06:12 PM   #3
AndrewT is offline AndrewT  Scotland
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Hi,
why 4*6.8V instead of 27V?

Why the 1k0 before 220uF elna?

Why use a plastic cap at the start of the RCRCRC string.

I think you would get better audio performance if the plastic cap was either at the end of the string or replaced the 47uF output cap. That 1600V 100uF must be as big as a car battery and cost the same as the car it fits in!

Can you modify your 1 (one) script, it is very ambiguous?
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Old 30th December 2005, 06:24 PM   #4
Tweeker is offline Tweeker  United States
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I think thats 100nF 1600V.
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Old 30th December 2005, 08:10 PM   #5
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Quote:
Originally posted by Tweeker
I think thats 100nF 1600V.
Yes, indeed.
I have a few hundred 6.8V Zeners, thats why...
I made a quick sketch of this but used only 3x6.8Z, because I found only a 18 VAC Transformer in my bin.
The 1k/220uF String is for filtering zener noise.

It works so far, now I need the negative rail.

How big can the output Cap (now 47uF) get, is there a upper limit?

Quote:
Originally posted by AndrewT

Can you modify your 1 (one) script, it is very ambiguous?
Not sure what you mean
Rüdiger
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Old 30th December 2005, 08:26 PM   #6
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Quote:
Originally posted by Onvinyl

The 1k/220uF String is for filtering zener noise.

Hi Rüdiger

For that purpose , the 150 Ohms resistor that come from the gate of the Mos-fet must be connected to the junction point of the 1K Resistor with the 200uF capacitor. This is what Technics call "Virtual Battery Operation".

The resistor that bias the LED must be connected between the base of the BC 560 and ground , that way the transistor could behave as a CCS.

Regards.
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Old 30th December 2005, 09:41 PM   #7
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Quote:
Originally posted by Tube_Dude



Hi Rüdiger

For that purpose , the 150 Ohms resistor that come from the gate of the Mos-fet must be connected to the junction point of the 1K Resistor with the 200uF capacitor. This is what Technics call "Virtual Battery Operation".

The resistor that bias the LED must be connected between the base of the BC 560 and ground , that way the transistor could behave as a CCS.

Regards.
Ok, I'll fix it. But, since the thing works as it is, how does the transistor behave now?

Regs,
Rüdiger
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Old 30th December 2005, 09:45 PM   #8
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Quote:
Originally posted by Onvinyl


Ok, I'll fix it. But, since the thing works as it is, how does the transistor behave now?
As a CCS with a resistor in parallel ...

Putting another way...a very bad CCS.
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Old 30th December 2005, 09:51 PM   #9
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Quote:
Originally posted by Tube_Dude


Putting another way...a very bad CCS.

Silly me

Thanks,
Rüdiger
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Old 30th December 2005, 11:22 PM   #10
Onra is offline Onra  Germany
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Hi,
i think you will waste a lot of power with this PSU.
For linear operation up to 1A the IRF610 needs a VGS of about 6V. The CCS needs at least 2V to stay in regular operation.
At higher currents the 10R-resistor will consume some voltage too.
Added you need an input voltage of about 30V to achieve a 23V output. That seems to much for me. Do you have to use this FET? A BJT wold do a better job here, because the staple of zeners can only be adjusted to a certain operation point and the output voltage will vary with the current.
For better drawings (and simulation) you may download switchercad III from:
http://www.linear.com/company/software.jsp
It´s a free spice without restrictions and very common.
Onra
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