Anybody Use the L200 Chip For Power Supply?

[CJ]

i need a cheap +/- power supply for my bench,

there is this L200 chip,

supposed to have plus and minus ready to hook up and your done.

add some cheap surplus digital panel meters and you have a 300 dollar supply on the cheap.

where can i buy this chip?

ok, i will search too, but if anybody has been there, done that, then chime in.

Thanks!

 

[CJ]

ok, lets keep it simple and build our way up.

i think i could actuall build this>

from
http://skema-elektronik.blogspot.com/2009/06/variable-power-supply-with-l200.html

"Voltage output is controlled by 10K variable resistor. Output voltage range value will be about 3 to 15 volts, and current range is about 10mA minimum and 2 amp maximum. Reaching the current limit will reduce the output voltage to zero.

 

[mad.ax]

That's an old and easy to use regulator...

Mouser says they have 235 in stock : 511-L200CV

The Thomson's 'A DESIGNER'S GUIDE TO THE L200 VOLTAGE REGULATOR' is quite informative.
http://www.st.com/stonline/books/pdf/docs/1678.pdf

Axel

 

[CJ]

somebody should put this in the drawing room, i don't know who the ******* was that started it here,

anyway,

check this:

put this circuit after the L200 and it is much simpler dual supply.

both sides are current regulated and voltage varied by the single supply ,

 

[mad.ax]

Should track well, and provides a virtual ground in case one would have only a non CT PT...
But you are limited to +/-18V output...

Axel

 

[radiance]

But you are limited to +/-18V output...

Axel

Maybe you could stack another L200 on top of the +Vcc rail, use a dual gang pot for output voltage and a switch for selecting 0-18V or 18-36V?
You'll need a transformer with dual secondaries as well then...

O wait, the idea was to keep this simple right? Ah well....

 

[mad.ax]

If you add a second L200 and a dual gang pot, you loose the output rails symmetry guaranteed by the second schemo.

Axel

 

[warpie]

being quite newbie to the whole thing can someone explain me the use of the 100n cap in parallel with the 4700u?
I understand the 4700u is for the ripple but the 100n?
sorry if I hijack the threat...

thanks
michael

 

[CJ]

the 100N is a hash filter for the hi end stuff,

the big lytics can have inductance, they are a big roll of foil, which acts as a coil in some ways,

a coil in series with hi end will block it from going to ground, but the 100N will bypass the hi end stuff

as it has smaller foil due the smaller value of capacitance required,



i see most of the  pwr supplies that offer bi polar mode simply strap two single mode supplies together,

so this means they use a transformer with floating secondaries, or dual secondaries,

we can ditch that idea, i can see where it could be a pain getting a matched transformer,

so lets go for a dual supply, one regular, and one bi polar,

use 2 L200 chips,

same front end circuit for both supplies, then just add the splitter for the dual supply.

if we want, we can get fancy with secondary switching on the transformer,
(what a pain, logic, comparators, relays)

or we can brute force it with a huge heat sink.

lets go for a mega heat sink instead of xfmr switching.

so lets get a schemo going,

 

[CJ]

ok, how does this Untested and Preleminary pwr sup circuit look?

we could use a dual sec xfmr, which would defeat our KISS principle, so screw it,

you just have to be careful.

so i put a fuse in the bipolar gnd just in case you connect the bipolar gnd to the other supply ground.

this might panic the two transistors into thinking one or the other should blow up.  ;D

ok, the lm358 could be crossed, the 2 transisto4rs could be crossed,

any ideas on easier p/n's for those guys greatly welcome.

 

[mad.ax]

What I like about the KISS principle is that I am often too stupid to be careful!

That fuse will blow way too often... What if i am playing with a 24V powered preamp feeding an AOPs based second stage?

Axel

 

[mad.ax]

Unless you plan do do something else with the second AOP, no need for a dual like the 358...

And for a lab supply, I'd like to be able to reach a little more than 2 X 15V. 2X 18 is the max that we can do with the L200, but this would smoke the 358's 32V limit...

5534 will stand 40V and is probably laying around any workbench...

If you must order, LM201 is dead cheap and looks good...

For the transistors, any complementary parts that happens to hold the max voltage and current should do....

Axel

 

[warpie]

Thanks for the explanation CJ 

 

[owel]

i need a cheap +/- power supply for my bench,
Thanks!

Just get an HP 6205C from eBay.  Anywhere from $50 to $125 or so.

I have this and it's a great bench PSU (but not high current), enough for powering/testing projects.

 

[mad.ax]

In another thread here http://www.groupdiy.com/index.php?topic=40228.0
the TLE2426 is mentioned...

$1.18 at mouser (or free sample at TI)

Could be a good alternative for the AOP and the 2 resistors forming the voltage divider... As it can deliver 20mA on its output, you would need to choose Q1 & Q2 with Hfe>100

Axel

 

[CJ]

Owel, you lucky dog, i looked all over evilbay for a bargain like that!

is HP Agilent now? if so, that is an older supply?

if this thing works, we get a dual and a single in the same box,

you might have to spend 500 dollah make me hollah for that,

250 ma fuse is not enough?

which circuit uses so much unbalanced current?

two supplies are cool for transistor load lines but not much use after that,

feel free to use a dual 24 volt sec xfmr to get a better box.

 

[emrr]

which circuit uses so much unbalanced current?

lots of 500 series gear full of relays

 

[CJ]

here is a xfmr with 2 ea. 24 volt secondaries if you want to provide better isolation between channels,

117/234 pri and 2 x 24 @ 2 A sec.

p/n 266L48

http://www.hammondmfg.com/266.htm

wow, 70 bucks from mouser,

http://www.mouser.com/ProductDetail/Hammond/266L48/?qs=vcFyY%252bOcAyhaKWkHhqWN4A%3d%3d

time to check evilbay, or get a single sec at 4 amps,

here it is: 

p/n 166N24

or, you could just use 2 ea.  single pri/sec for isolation on the cheap,

get some control transformers from surplus,

ok, the hammond 4 amp is only 31 bucks at digikey, half the price?

http://parts.digikey.com/1/parts/999548-transformer-115vac-24vct-4a-166n24.html

 

[Andy Peters]

i need a cheap +/- power supply for my bench,
Thanks!

Just get an HP 6205C from eBay.  Anywhere from $50 to $125 or so.

I have this and it's a great bench PSU (but not high current), enough for powering/testing projects.

Gimme.

-a

 

[owel]

There's a $95 unit right now on eBay.
http://cgi.ebay.com/HP-Agilent-6205C-011-DC-Power-Supply-0-40V-0-3A-Optio-/110534710616?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item19bc61d558

You are bidding on a used, in good condition, Agilent HP 6205C Dual DC Power Supply. Thank you for looking and good luck!!

Description: The HP 6205C Power Supply has an output rating of 20V/0.6A and 40V/0.3A,. The 6205C combines the versatility of a dual power supply with the flexibility of auto-parallel and auto-series operationis a bench supply. It is equipped with ten-turn output voltage controls, volt/ampere meter, meter function/range switch, and front and rear output terminals. In addition, an output range switch permits the selection of either a high or a low output voltage range.