Hi

I am looking to build a dual polarity power supply for prototyping my projects. I am looking at
a variable output voltage of +/- 0 to 40V DC, max current drawn 5A DC. Does anyone know any circuits that can do this ? I was searching for RC4194 based designs and LM317 / LM337 based designs. Any suggestions ?

Thanks

 

hi,
The RC4194 dual tracking psu ic, is a bit dated, circa 1977.

May I ask why you require a -40V psu at 5Amp.?

EDITED: added a pdf
This pdf shows some applications for the RC4194

Attached Files

4194.pdf (99.3 KB, 38 views)

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Another choice would be the LM350T. It's a drop-in replacement for the LM317, but does 3A instead of 1.5A. (And Eric may be right, 5A for the negative supply is likely much more than you would ever need.)

To get the LM350/LM337 to 0V, however, you have to muck with them a bit. Without adding some opposite polarity biasing in the adjustment legs, they both start out at about 1.2V. And you'd have to add some circuitry to make them track, if so desired. There may be some good single-chip tracking regulators out there, but none are coming to mind.

EDIT: I forgot the LM338K: another replacement for the LM317, but does 5A.

__________________
Corey

Rapp's Law of Inanimate Reproduction:
"If you take something apart and put it back together enough times, you'll eventually have two of them."

 

Ericgibbs, a number of the circuits that I want to prototype ( most of them are audio power amps, though not all) require supplies dual polarity supplies +/- 35Vdc at 2A. I gave upper limit of 5A. They are all discrete transistor based designs from Phillips design audio amplifier design book. Do you forsee any problems with the power supply ?

 

hi,
If you look at the pdf I posted, it shows a high current dual tracking power supply circuit.
Dont exceed the input voltage rating of the RC4194.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Be warned that +/-40V is 80V which is verging on hazardous voltages.

__________________
I also post at the following sites:
http://www.stop-microsoft.org http://www.heated-debates.com
Screen name: Aloone_Jonez
And http://www.silicontronics.com, same screen name as here.

 

Probably your most difficult requirement is the 0V minimum. Your monolithic regulators tend to have a reference around 1.2V. And, at 5A, at any low voltage, the pass elements must dissipate 5A*(Vunreg - Vout).

A much easier design would be +/-20 to 40V @ 5A. (With option for voltages below 20V at reduced current.)

From a practical sense, do you really need a regulated supply? You may find that a +/-40V unregulated (simple bridge on a 56VCT transformer), supplied by a 500VA variac would suffice. It would be a lot cheaper.

 

Right, I mentioned this above.

This is a great point. But, it's still do-able if one really wants it. Many commercial power supplies use relays to switch to lower voltage secondary taps...

__________________
Corey

Rapp's Law of Inanimate Reproduction:
"If you take something apart and put it back together enough times, you'll eventually have two of them."

 

hi,
The RC4194 can go down to 50mV Vout.
I wouldn't recommend using for a new project, because of the availability.

It was a 'nice' device, especially the dual tracking feature.

Attached Images

esp01 Jul. 23.gif (26.4 KB, 10 views)

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/