4quad supply

Ha ha ha. I drink what I like.

For the longest time, I thought I just didn't like beer.

I finally found a few I liked, though, mostly from Eastern Europe.

Then again, the only wines I like are sweet ones. I guess I'm just abnormal like that. :)

Cheers

Michael

Interesting, thanks.

There are Certain Parties Here that want to use switchers instead of linear regs. What's interesting is that a switcher is theoretically

100% efficient, so if you are operating in a quadrant where the switcher is absorbing power, the absorbed energy has to go somewhere. That means you wind up charging one of the power supplies. That's OK if you are sure there are more loads on that supply than the switchers are pumping in.

A linear reg just burns up all that donated energy.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

Ahhh... How fast are the regulators? Then again, a power opamp for less than the $5-10..

George H.

There is a certain party here who didn't like beer, so wasted over half his lifetime pointlessly. I sent him a 6-pack of something decent and changed his life. So now he mostly insults me; he must be a mean drunk.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

Linear is nice if you can get rid of the power. If it calls for fans....

George H.

Ideally. Pushing current backwards into your average 3-terminal regulator is not a growth strategy. ;)

Cheers

Phil Hobbs

Yup :-)

But whether switcher or linear, there is never more energy coming back than the power rails delivered. If there ever is then it would be time for a Nobel prize nomination.

--
Regards, Joerg 

http://www.analogconsultants.com/

Half-bridge switching audio power amps, driving transformers or speakers, or especially motors, can transiently absorb power. I have a Motorola appnote around somewhere, for such an amp, that warns about the hazard.

A half-bridge buck switcher is a lot like a gear set.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

My customer can push power into my pulse generator output. Like if I'm outputting +3 and he terminates to +5.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

The linear version also only has the supply rails for handling this situation. An opamp cannot shunt away excess energy because it usually does not have a ground connection. When I went to switched solutions for stuff like this I found that (provided the EMI situation was handled well) the main difference was a huge drop in dissipation and heat.

Switchers are really nice. A customer just asked me whether my design could handle 10x the originally spec'd peak power. It won't be a problem. This one is only two quadrants but hardcore push-pull.

--
Regards, Joerg 

http://www.analogconsultants.com/

Have you considered a plain old linear audio amplifier? They are often just glorified opamps, way faster than audio and come with a cooling tab.

It didn't grenade but even after spending a couple of hours in the fridge the growler let of an evil hiss and a 5ft jet of foam shot across the kitchen when I opened it (despite my palm gradually releasing its flip-top lid).

These guys are pretty direct when it comes to voicing opinions :-)

Zero sugoar here.

You'd probably like the Golden Ales out here. Usually around 5% and not hoppy in taste.

--
Regards, Joerg 

http://www.analogconsultants.com/

In the case noted, the current will come from the opamp negative supply. So the customer's power input becomes heat inside the opamp, but no supply gets back-driven.

I'd need eight bipolar switchers in my box, each closed-loop, as opposed to four SO16 dual opamps. That's a lot of parts and area and EMI/jitter. One fan seems like a reasonable tradeoff. The debate continues here.

But first, I have to get the fast stuff to work. The supply rails are sort of a side issue.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

I guess I should. I've never used audio amps, but they are the sort of things I need. I'd likely need to wrap an opamp around an audio part.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

I'm sure you know there are a number of power opamps...

10 to 100 times as much as the TCA0372.

George H.

Den fredag den 8. april 2016 kl. 02.40.08 UTC+2 skrev John Larkin:

yeh, a half brigde with bipolar supplies and an asymmetric waveform you can pump energy from one rail to the other

-Lasse

Den fredag den 8. april 2016 kl. 17.52.47 UTC+2 skrev John Larkin:

how about an opamp and two transistors ?

ala' classic voltage regulator, just with both source and sink

-Lasse

It's the same in the switcher solution. The switcher tries to force a lower voltage and thus pulls against the negative rail. The difference is that almost the whole net energy transfer happens between you supply and the customer's.

Then the linear solution is best. But I'd be concerned about thermal stuff when using such a small opamp. Unless you tie each opamp's rails into the loop like Phils suggested, to move dissipation towards the supply regulators.

--
Regards, Joerg 

http://www.analogconsultants.com/

No need for an extra opamp. Many audio amps are essentially opamps with power device and a heat sink pad added in. So you have IN+, IN- and the speaker connection from where feedback can be arranged. Offset and drift specs are often lousy though because that usually does not matter in the world of audio.

--
Regards, Joerg 

http://www.analogconsultants.com/

Do you have a more professional setup with stainless fermenter, bottom trap for the trub and all that?

When my current work load lights up which will hopefully be in a month or two I want to start brewing again. But not having done it for 35 years I'll be a rookie. No equipment whatsoever yet and I still have to empty another 20 Grolsch bottles that I like to use for bottling. That's a very small problem though :-)

A month ago on one of my bike trips I re-discovered Brewmeister in Folsom and checked it out. They seem to have everything needed. To my surprise even new rubbers for Grolsch bottles.

--
Regards, Joerg 

http://www.analogconsultants.com/