<1VDC Regulator

All,
I need some help designing a <1VDC regulator (ideally, 0.1VDC minimum) and I haven't been too successful. I found the following article:
http://www.powermanagementdesignline.com/howto/164300442 .
But when I simulated it in Circuitmaker 2000 with an adjustable regulator (LM317), I wasn't able to get the <1VDC results as shown. Has anyone verified the results from the article above? Or have any other ideas on how to get <1VDC?
Thanks,
Abe
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The trick to getting a 0 to whatever voltage using a 317 is to have a negative voltage supply that serves as a reference point to the regulator in addition to the positive supply. I have used a couple for this, one fixed for the negative reference and the variable one driving pass transistors.
A cheaper trick is to simply add diodes (or a zener) to the ouput of the 317 (but it wont help is you are driving pass transistors for a high current output).
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snipped-for-privacy@gmail.com wrote:

It works. I used that technique to produce a 0 to 100V DC 0 to 10A power supply, adjustable in steps of 10mV and current limit in steps of 10mA as my first degree project, more years ago than I would care to mention...
I suspect that you are getting your common references mixed up..
Try this: Model a standard dual (positive and negative rails) regulated supply. Say +15v, -5v. Now add an additional adjustable positive regulator that takes the +15v as input but uses the -5v rail as the common reference. Set its voltage to +5.1v wrt its reference, the -5v rail. You then have a +0.1v regulated supply, using the output of the adjustable regulator wrt the common reference of the +15v regulator..
--
Sue






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Thanks Time and Sue,
I understand what you guys are saying. Now, I can definitely simulate and get the <1VDC now with a negative voltage reference. (That 0-100V, 10A adjustable regulator is pretty cool.)
But the thing I still don't understand is that the article seems to insinuate that one can use only positive voltage supply references. Is this not true then?
Thanks,
Abe

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snipped-for-privacy@gmail.com wrote:

I couldn't find where in the article you read that. However, an offset zero reference works, irrespective of whether the offset is negative (for a positive output supply) or positive (for a negative output supply. Where one has a dual regulator, producing both positive and negative output voltages, the offset reference is automatically included "at no extra cost".
Another neat little trick is to use a high power bridge operational amplifier (or even some audio amplifiers) - these can be used to produce a dual output power supply where each output can be varied over a wide range of both positive and negative output voltages, plus achieve tracking "at no extra cost"..
--
Sue

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wrote:

I have heard of using a Crown DC series amps to charge car batteries in a pinch by applying a small battery voltage to the input.
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Tim Perry wrote:

I jump started a car once by rolling my bumper to the other car's bumper, and used a six foot scrap of solid aluminum clothesline wire between the positive terminals. Luckily, it started the first try. The wire was too hot to hold onto after that. :(
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