What to make of this regulator?

[mfrimu]

Hello,

I have thsi regulator left from another project, wondering how good it is, if used for a 150mA or so preamp project. I will have to change the zeners for appropriate voltage.

Any improvements suggested?

Thanks!

[AndrewT]

note that the opamps are supplied by the unregulated voltage at the smoothing caps.
What is the maximum operating voltage of the op249g?

I suspect a 9V transformer already takes them to within a few % of maximum operating voltage when taking worst case conditions into account.

[mfrimu]

Supply from datasheet is Min 4.5v Typ: 15v, Max 18v. Thanks for the tip, as I was planning to get closer to 18v, now have to be careful.

[AndrewT]

9Vac already takes the device way past 18Vdc.
Could the 249 specification actually be <=36Vdc?

[mfrimu]

Correct, I assumed otherwise. I looked at the PCB and found errors in the schematics.


Actually I have 2 versions of this supply, and there was a mistake in the schematics around the OPAMP output (fixed). I've attached both.

One is 5v (in use) and concerned about the 18v OpAmp supply.

The second is a 15v one I'd like to use for 16-17v supply (by changing the zeners). However not sure about the 10v Zener...

And overall, is this design any good? Should I fix the 9v one and further improve the 15v one?

Possibly, the first schematic (top post) might have been a suggested fix, I forgot.

Thanks, I'm learning.

[mfrimu]

I found that NE5532 runs at 22v.

This could be a fix for the OpAmp. ?

http://www.datasheetcatalog.org/datasheet/fairchild/NE5532.pdf

[mfrimu]

OP249


ABSOLUTE MAXIMUM RATINGS

Supply Voltage +/- 18 V

Input Voltage +/- 18 V
Differential Input Voltage 36 V
Voltage Supply Range VS min +/-4.5v typ +/-15v max +/- 18v

So OP249 should be ok.

[darkfenriz]

Originally Posted by mfrimu

And overall, is this design any good?

So-so.
Let's say it's good.
The question is why not us an IC regulator for regular job and something really sophisticated for high quality supply.
I don't see a point in using something this complicated, when its supremacy to say lm317 is questionable.

[mfrimu]

Hmm, I'll use it as a preregulator for a simple shunt regultor then.

Question: The current 15v version uses 15v and 10v zeners. If i wanted to raise to 18v, appart from upgrading the opamp, the 15v zeners would get changed to 18v, but the 10v one?

Thanks

[AndrewT]

The higher voltage regulator uses separate supplies.
+-15Vdc for the opamp.
Rectified and smoothed 18+18Vac for the power input.

The lower voltage regulator uses rectified and smoothed 9+9vac for the opamp and the power input.

Don't get the two regulators mixed up.
Changing to a 40Vdc or 44Vdc opamp is not going to allow your higher voltage regulator to survive 18+18Vac if you omit the separated supplies.
If you keep the separated supplies, then you don't need a higher voltage opamp.