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hamedfazelm 27th July 2010 06:59 PM

Adjustable +/- 0-50V 0-5A Power Supply Schematics
 
Hello
I need schematics for Adjustable +/- 0-50V 0-5A Power Supply.
Thank you

bob91343 27th July 2010 08:27 PM

You can look up the diagrams of some commercial units. Or design your own.

Start with a power supply that will deliver at least 55 V (at ripple troughs) at full load current of 5 A. Put in a series regulator stage, probably several transistors in parallel on a heat sink (with emitter equalizing resistors). Drive with a reverse polarity transistor.

Drive said reverse transistor with another transistor, either a differential pair or an opamp or just a single transistor. Use zener as reference, pot to control other input. Or the classic uA723.

The only problem with this approach is that it won't take the output to zero. You can devise various methods to do that if it's needed, like tying the reference to a negative supply.

Sch3mat1c 28th July 2010 05:02 AM

Depending on how much you'll be using it at low voltage and low current, I would build a forward converter, or hybrid (~60VDC supply with buck converter).

A combination switching supply with linear postregulator could work very well indeed at all voltages and currents.

Tim

WALTER BURKHARD 28th July 2010 05:55 AM

Adjustable +/- 0-50V 0-5A Power Supply Schematics
 
Contact by email.

I build one Adjustable +/- 0-50V 0-3A tracking Power Supply.

regards Walter

WALTER BURKHARD 28th July 2010 07:00 AM

Dual PS
 
2 Attachment(s)
Drawing and BOM

regards

Walter

Elvee 28th July 2010 08:38 AM

This one is a single polarity 0-50V. The example shown is configured as a 0-2A, but it can be adapted to another current value by modifying R9 on the schematic.
Further down the thread, some accessories are described, such as automatic winding switching, and also the way to couple two units to make a +/-50V supply.
This circuit has the advantage of requiring no auxiliary supply.
http://forums.futura-sciences.com/pr...reference.html

joaquim 3rd August 2010 10:00 PM

Very innovating "Lab psu", how ever there's a much easier way, use a trafo. with a secondary of 2x36 - 40VAC, a rectifier bridge, 10mF 100V cap's and a VARIAC, on the mains..... They can be hard to get, but look on e-bay.... 3A 0 - 250VAC(or 115VAC US), and the "unregulated" traf of 2x36V~, which becomes about 50VDC rectified and noise free(bigger cap = less 'hum'), and 3A times 250VAC, comes to 750VA, which ought to be enough(but you'll need a pass transistor if you wanna ctrl the current, and the circuit looked kind of tempting...)

dangus 8th August 2010 07:15 AM

The LM10CH application notes include a floating lab power supply regulator. Motorola used to make a chip that was specifically designed for lab power supplies, but it's been discontinued for some time. Still, the application note may be useful since I'm pretty sure it talks about how to choose the power transistors.

Here's a power supply that recreates the Motorola MC1466 chip using discrete devices:
Super Power Supply, Current and Voltage Regulated

jackinnj 8th August 2010 01:28 PM

Quote:

Originally Posted by hamedfazelm (Post 2255458)
Hello
I need schematics for Adjustable +/- 0-50V 0-5A Power Supply.
Thank you

For testing amplifiers I have used a Variac on a dedicated amplifier power supply -- 600VA transformer from Antek and 25,000uF on each rail. I took the amplifier parts out!

Sometimes HP 6271, 6274 rack mount supplies can be found at hamfests.

joaquim 8th August 2010 05:38 PM

Quote:

Originally Posted by dangus (Post 2266093)
The LM10CH application notes include a floating lab power supply regulator. Motorola used to make a chip that was specifically designed for lab power supplies, but it's been discontinued for some time. Still, the application note may be useful since I'm pretty sure it talks about how to choose the power transistors.

Here's a power supply that recreates the Motorola MC1466 chip using discrete devices:
Super Power Supply, Current and Voltage Regulated

LM12CLK is still available... it can handle 50V@2A... and has a nice simple LAB-psu application on the datasheet.


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