How to generate clean +/-12V for op-amps from +5/3.3V?

If you don't need the rails super precise:

I believe TI also makes regulated ones and also multi-output varieties. Check it out.

If price is no object, and you can actually find some (demand is greater than supply), then these are quite nice:

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Greg Neff VP Engineering

Sure:

Cheers! Rich

Does "tracking" count as "regulating"? :-)

Thanks, Rich

That's what our rottie thinks during walks. As long as there are no more than 50lbs of pull force on the leash it's tracking ;-)

In my experience, the TI/Burr-Brown integrated isolated converters are incredibly noisy. They especially put a burden on the primary side. They seem to be forward converters with no series inductor....primary current seems to be limited by only by copper resistance and leakage inductance. Not recommended for analog electronics, IMHO. Paul Mathews

Interesting. Our Rottie is really a mix between a Rottweiler (purebred, German books and all) and the father is an Aussie Shepherd and Queensland Healer mix. An "accident pregrancy". Very lovely dog, huge, markings of a Rottie but longer snout. The other dog is adopted, most likely a German Shepherd and Retriever mix. She is very pretty, but can be a brat. Keeps the Rottie from becoming to complacent, shaved his sleeping time down from his desired 16hrs/day.

Once Rottie ran after a cat and I held the leash. Choke chain (!). Ran full bore into the collar, neck stopped, rest of body continued and landed on his back. I have never seen such embarrassment in the eyes of a dog. His ego was kinked that night but luckily he wasn't hurt.

When the leaning angle exceeds 30° ?:-)

Dachshunds don't have that much pull. The only problem was with the old guy we had to finally put down this past spring... he'd just sit down and refuse to budge. Then I'd have to carry him home... all 35# of him :-(

...Jim Thompson

You have that problem also! We also have a Rottie & German Shepherd mix, she seems to exhibit tug of war syndrome.

Oh, I hold my posture and Rottie knows. But he doesn't learn. Well, at least it all goes out the window the millisecond he spots a cat.

I don't even want to think about that but larger dogs don't get too old. Dogs really try to please you. When they refuse then it usually means they really can't go on.

I have 2 tubes of OP747's ordered by mistake.. I requested LM747 to repair some older equipment. got those instead. oh well. :)

Are you interested in unloading some at a loss?

How the master did it 20-some years ago...

...Jim Thompson

VOUTN doesn't look very regulated, just crowbar'd.

Man, why are you guys using such humongous caps on switcher outputs? Joel also did that. I already wince if I have to spring for more than a couple uF (ceramic, of course).

Come on, Joerg, read carefully before you plunge. The SCR bypasses the flyback current that _was_ going into the negative load when regulation is reached.

This was around 1980... switching frequency was just above audible ("controller" was LM339 ;-)

...Jim Thompson

and

to

to

how about these?:

-Lasse

Aha, clever. I never designed switchers under 100kHz so I didn't notice that detail. Up there you can't really do that, at least not when the client wants lots of efficiency.

Nowadays inductors and FETs have become so cheap that it's really no big deal to run a complete 2nd track as long as the oscillator is dirt cheap, meaning its part of a hex Schmitt.

Wonder whether Digikey has any MyZeners in stock ;-)

At least you could hear when they began to squeal and head for cover.

MyZener is a PSpice part I created that allows me to enter BV, IBV, R, etc., for any zener value I want.

...Jim Thompson

Ok with out doing any math, after looking at the circuit, I'm guessing that X1 (Thyristor) does not switch on rite away when M1 opens? That would give you a negative pulse that you could use via the inductor back over to the + side output as your path.

At a quick glance, it looks like the (+) output side is a boost since while the M1 is on, you'll get a minimum of 12 volts+ there. and the charge quantity from L1 is what you'll get, minus what is appearing at VOUTP ? so, on the (-), all source of energy is 100 % dependent on the discharge of the coil at the time when M1 turns off and before X1 turns on ? This was just a generalize view of what you posted there. I would think deriving (-) that way could effect the ability of the (+) side to boost? I don't see the actual output voltage labeled there so I don't know..

I love pawing over circuits. ! I do like it, It's small and simple!

Have a good day Sir. :)