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Old 21st April 2004, 05:53 PM   #1
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Question To good to be true?

Hi, I came upon this post by James Bongiorno. A powersupply regulator with only two transistors. "Positive feedback"? Anyone has an idea what this might be???
http://groups.yahoo.com/group/SAE_Talk/message/7561
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Old 21st April 2004, 07:23 PM   #2
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Elso, we missed you on DDIY2004! (I know).

On the Bongiorno thing, I have no idea what he is talking about. His post is almost content-empty, which doesn't help either. Of course, 'rock steady' and 'dead quiet' are not easily verified in engineering terms...

Jan Didden
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Old 21st April 2004, 08:36 PM   #3
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Default Re: To good to be true?

Quote:
Originally posted by Elso Kwak
Hi, I came upon this post by James Bongiorno. A powersupply regulator with only two transistors. "Positive feedback"? Anyone has an idea what this might be???
http://groups.yahoo.com/group/SAE_Talk/message/7561
Geez, you have to have a user ID and password just to read a message there?

se
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Old 21st April 2004, 09:10 PM   #4
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Lightbulb Re: Re: To good to be true?

Quote:
Originally posted by Steve Eddy


Geez, you have to have a user ID and password just to read a message there?

se
Seems to be so. Here is the message:
Quote:
From: James Bongiorno <sstinc@e...>
Date: Tue Apr 20, 2004 5:30 pm
Subject: Re: [SAE_Talk] ATI Amps

Thanks for the compliment. Actually, that IC regulator in the Thaedra was quite
unique. I have since (after about 30 years) come up with something even better
which is in my Trinaural Processor and will be extensively used in my new
Ambrosia. I call it my "positive" feedback regulator. It's a real gem and very
simple. It is dead quiet and is as stable as a rock and only uses TWO
transistors. Enough for now.
James Bongiorno
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Old 23rd April 2004, 07:21 AM   #5
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I am always skeptical of radical claims in this field.

Bongiorno is a genius, technically and as a huckster. I fear this one is more marketing blarney than technical breakthrough.
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Old 23rd April 2004, 08:17 AM   #6
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Well you can make a pretty reasonable fixed output LDO regulator with only two transistors, but you do seem some zeners!

The general arrangement shown below works.
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File Type: jpg regulator.jpg (18.0 KB, 1275 views)
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Old 23rd April 2004, 08:19 AM   #7
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The regulator in my drawing outputs 36V (or near enough)
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Old 26th April 2004, 05:20 AM   #8
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how does it work?...almost looks like a switch. you will have to forgive my ignorance...my electronics is poor
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Old 26th April 2004, 08:16 AM   #9
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Zener Z1 sets a 10V reference at the base of T2.

Initially the output of the regulator is at 0v. The emitter of T2 is low so T2 is on, and current flows through T2 to pull the gate of the P-ch FET T1 down, so that current flows to the output. As the output rises, then at approx Vout = 36v then the emitter of T2 will approach the base voltage, slowly turning T2 off. This in turn starts to turn off T1 in a negative feedback loop, keeping the output regulated.

Vout = V(Z1) + V(Z2) - Vbe(T2). Or near enough.

The Cg-s of the FET is enough to keep it stable, but you normally need another zener (10v or so) across G-S of the FET to prevent Vg-s from getting too high.
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Old 26th April 2004, 08:17 AM   #10
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If it's the same as Ouroboros schematic, I don't see were the positive feedback is

And what is so good about positive feedback?
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