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Complementary Reference Supply Help

Need circuit design help for a reference supply. Runs off of +12 and - 12 Vdc supplies with adaquate current available. Must have two outputs; one positive and one negative. Reference does not have to be the same absolute value but within a volt or so, e.g. +10 / -9 supplies are a +/- 0.5 vdc. they do drift some but I have no specs. the supplies are from a typical switching P/S.

Reference Circuit output should be: each output as close to the same polarity rail as possible., say 10 vdc. each output be stable with respect to common. i.e. not dual tracking. each output to supply up to 50 ma.

My simple minded solution is to use one reference and two op amps; one inverting to get the voltages but I would suspect that there is a better way. Hopefully with a minimized thru-hole component footprint.

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Reply to
OldGuy
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The usual way is to employ a pair of linear voltage regulators, like LM317L or LT1120 and a negative equivalent, with resistors to set the reference ratio and capacitors to suit. The 50 mA requirement (I'm assuming it isn't a constant 50 mA, but a range of zero to 50 mA) is a bit stiff for a simple op amp, you'll benefit from heatsinking and a good thermal design.

If there are knowable noise, aging, accuracy requirements, it might be possible to examine LOTS of specifications of LDO regulators to come up with some kind of optimum choice.

Reply to
whit3rd

OldGuy brought next idea :

Reference as in very stable outputs. It is much easier to work a circuit forward for me that to work it backwards so I cannot give a stability right now. Going for reasonable good stability of a realizable reference so I can work it forward into the circuits that will be using the references.

Should have added: The load is constant but may be in the range of a few ma to 50 ma.

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Reply to
OldGuy

I'd probably use a TCA0372 dual power op amp and an LM329 or LT1021, because I'm generally more concerned about 1/f noise than with temperature drift.

With a 1.3-A op amp, dual tracking is a very reasonable approach.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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ElectroOptical Innovations LLC 
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Reply to
Phil Hobbs

Well the 50mA makes it harder. But I was going to suggest a REF102 10V reference and then opamp inverter for -10. you'll need some more poop after the ref102.

George H.

Reply to
George Herold

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