To good to be true?

Elso Kwak · 21st April 2004, 04:53 PM

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

janneman · 21st April 2004, 06:23 PM

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

Steve Eddy · 21st April 2004, 07:36 PM

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

Elso Kwak · 21st April 2004, 08:10 PM

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

slowhands · 23rd April 2004, 06:21 AM

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.

Ouroboros · 23rd April 2004, 07:17 AM

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.

Ouroboros · 23rd April 2004, 07:19 AM

The regulator in my drawing outputs 36V (or near enough)

demons_wing · 26th April 2004, 04:20 AM

how does it work?...almost looks like a switch. you will have to forgive my ignorance...my electronics is poor

Ouroboros · 26th April 2004, 07:16 AM

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.

Bricolo · 26th April 2004, 07:17 AM

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?

21st April 2004, 04:53 PM	#1
Elso Kwak Banned Join Date: Dec 2001 Location: Zamboanga, City of Flowers, Mindanao	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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21st April 2004, 06:23 PM	#2
janneman diyAudio Member Join Date: May 2002 Location: Where Germany, The Netherlands and Belgium meet Blog Entries: 6	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

23rd April 2004, 06:21 AM	#5
slowhands diyAudio Member Join Date: Feb 2004 Location: Silicon Valley	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.

23rd April 2004, 07:19 AM	#7
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	The regulator in my drawing outputs 36V (or near enough)

26th April 2004, 04:20 AM	#8
demons_wing diyAudio Member Join Date: Apr 2004 Location: BC	how does it work?...almost looks like a switch. you will have to forgive my ignorance...my electronics is poor

26th April 2004, 07:16 AM	#9
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	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.

26th April 2004, 07:17 AM	#10
Bricolo diyAudio Member Join Date: Nov 2002 Location: Grenoble, FR	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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