Unusual Bias Method

Of course, as in this OpAmp of my design (2011)...

A couple mA of "overlap" current, with 100mA rail-to-rail output (and rail-to-rail inputs as well :-)

But you're trying to compare apples and oranges... my bipolar design dates to 36 years ago, power MOSFET's were just under development in the late '70's.

I was on the team evaluating the Challenger disaster in 1987. The power supplies were so "redundant" that one failing caused all the others to fail. Rather than totally redesign the whole power supply system, requiring a monumental requalification time and effort, I designed a simple connection circuit between the supplies and managed to get HEXFET's space-qualified for the first time. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Every schematic I've posted works. Quite a few are still being manufactured... including one designed in 1963, see...

Once you admit ignorance I'll walk you right thru it. I remember it quite well because this was the discrete implementation of an I/C I conceived (written up and witnessed in my OmniComp/GenRad engineering logbook). ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Tim, Since you were previously designated a jerk, I didn't see your post. I see that you remain a jerk, and incompetent. Jerks who don't understand circuit functions should avoid claiming "analysis".

Emulating Tim, I see >:-} ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

On a sunny day (Mon, 25 Nov 2013 11:13:23 -0700) it happened Jim Thompson wrote in :

I have herd you talk abut that Motor-oil-a what was it - RS232? - or something chip. Nice.

Well things have changed,,, They get smaller and use class D sometimes.

That was just for fun.

I dunno why you keep attacking J.L, he posts some intersting stuff here, try it too.

Now, when you said chandelier, I thought you meant one of those hundreds of crystals things that you get to assemble yourself! That is just a light fixture... ;-)

Charlie

Fricking thing weighs 15#. With my right shoulder rotator cuff gronked from reaching out too far to pick up a propane tank last May, I'm very cautious... propped the whole thing up so that I didn't have to juggle fixture and wires simultaneously.

That scaffold assembly cost me only $100 at Lowe's (I get a contractor's discount :-), cost me less than hiring an electrician to hang them (*) for me.

(*) A more complex one to go for the dining room... but should be simpler, it assemblies from the ceiling down, don't have to support all that weight while wiring. Breakfast nook "fixture" is as you see it... the dummies didn't design it so pods could be hung after ceiling wiring.

Then come the ceiling fans. New houses are such fun ;-) ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

[ignorance snipped]

Please, old great pontificator, what IS the "gain" from the LM311 inputs to the base-to-base bias.

I will temporarily un-killfile you so that I can be educated by your great store of wisdom >:-}

Nonsense. Properly analyze the circuit and show us. I'm particularly interested in how it varies with "signal level"... that's a trap... it DOES vary with signal level, but not like you think. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

He doesn't want to be interesting or helpful. He wants to prove that he's smarter than us. That's really dumb.

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John Larkin         Highland Technology, Inc 

jlarkin at highlandtechnology dot com 
http://www.highlandtechnology.com 

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom laser drivers and controllers 
Photonics and fiberoptic TTL data links 
VME thermocouple, LVDT, synchro   acquisition and simulation

Nope. I just want you to stop denigrating circuits that I post... circuits that are known to work and many in manufacture.

But you just have this need to be an asshole. And you _are_ really good at that >:-}

I thought that bias scheme was rather "interesting". However it doesn't work anything like you (or Tom or Jan) think it does.

And I have posted _many_ more _working_ circuits to S.E.D than you have. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

A church in Gila Bend decided not to get a chandelier because nobody in the congregation knew how to play one.

Tuning was also a bear.

--
Many thanks, 

Don Lancaster                          voice phone: (928)428-4073 
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552 
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com 

Please visit my GURU's LAIR web site at http://www.tinaja.com

Probably located next door to the Space Age Restaurant ;-)

Actually pretty good food. When we drive to Yuma we often stop there for breakfast or lunch. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

Not what the LM311 is doing at all. It is mainly about output over current protection, SOA seems to done with total supply voltage and Ic limiting only, nothing too difficult about that.

I still don't have all of it figured out yet. It is certainly not a standard Vbe multiplier bias. It also seems that Q8 keeps Q10 slightly in conduction (about 0.8 mA) to eliminate most crossover distortion. Plus, there is something i an not quite getting on centering the two sides of the full H.

?-)

You're getting closer. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

It's detecting when there's no current on either .33 Ohm resistor. While that happens, the bias is raised. When it's not happening, the bias gradually decreases. Essentially, it's trying to detect when push-pull crossover distortion is about to happen and compensate.

It appears to be a little bit defective. This circuit can only check the bias at moments when there's no significant output current. Strong high frequencies could keep the op-amp seeing current flow even as the bias is decaying too much. When the high frequency content is gone, there's a rasp of crossover distortion until the circuit adjusts.

I've played with self-adjusting circuits too. Something like this worked in a small test circuit:

I never came to trust them, as there always seemed to be some condition of load, voltage, and frequency that could make them glitch.

A breath of fresh air... you're very close... "...no significant output current..." is the clue. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.

On a sunny day (Mon, 25 Nov 2013 15:24:05 -0700) it happened Jim Thompson wrote in :

Elector, (magazine) used to once a year publish a hundred circuits, no not in the April issue... Dunno if they still do it. Some were very simple, some were too simple, some worked. But to build one, make a youtube video of one, that is more the real thing. Simulations are like NASA, artist impressions of far away planets.

Several people have claimed it has failure modes. Will you put it into spice and show what really happens?

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Reply in group, but if emailing remove the last word.

He has played this way beyond what it's worth. Ignore him.

--

John Larkin         Highland Technology, Inc 

jlarkin at highlandtechnology dot com 
http://www.highlandtechnology.com 

Precision electronic instrumentation 
Picosecond-resolution Digital Delay and Pulse generators 
Custom laser drivers and controllers 
Photonics and fiberoptic TTL data links 
VME thermocouple, LVDT, synchro   acquisition and simulation

Obviously a shorted output may kill it before a fuse blows, but there are no other failure modes, no matter what people hand-wave and claim.

Larkin is the one who should be ignored. All he provides here is smug denigration. I cannot recall a single instance where he has provided a true engineering analysis... just hand-waving.

Since I save everything >:-}, I looked up my posting record... to date I have posted 1500+ schematics or links to schematics on S.E.D or A.B.S.E

And there are 497 currently available on the S.E.D page of my website,

30 downloadable Spice models on my Device Models & Subcircuits page, and 7 discussion topics on the Simulation Tools & Macro page.

What does Larkin have to show for himself besides being beyond being obnoxious?

But I will enter it into Spice... it was originally designed and built BC (before CAD :-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| San Tan Valley, AZ 85142   Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.