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Looking for voltage regulator which can go till 0 V

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somf0872

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lmxxxx adj

I need some variable voltage regulator like (LM317, LM2941, LM200, etc etc) that can be able to vary the voltage till OV.

I mean in all the above mentioned regulators, the limitation is that u can't go till 0V. Some have limits till 1.3V and some 5V.

Does anyone have an idea that how to achieve variable behaviour of this regulator till 0V or is there any LMXXXX that can do it.

--X--
 

ceaser

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lm200 regulator

i think you should use a variable resistance at the output of the regulator in parallel with its output
so if the res. is large you can have the volage of the regulator
if the res. is 0 ohm the output will be zero
and the current of the regulator is not large to defect any thing
 

IanP

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voltage regulator 22re

If you connect 2 silicone diodes (1N400X, 1N540X ..) in series with the output of the 317 voltage regulator the voltage will be reduced by 0.65V+0.65V≈ 1.3V and this "trick" ,in fact, shifts the output level from 1.3-16.3 to 0-15V ..

Regards,
IanP
 

E-design

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all lmxxxx regulator

Theoretically this can work but the voltage drop over the diodes also vary with current. So voltage regulation may suffer between no load and full load. If you are not worried about a few 100mV change then it should be OK.

Another way of doing it if you have a negative voltage available is to reference the gnd end of the resistor to a min of -1.25V or more instead of gnd
 

BabyTiger

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Re: Voltage Regulator

I think that, you may look about LM2575T-ADJ from National.
 

Verba

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Voltage Regulator

i don't know what is your load current, but may be you can just use some buffer connected opamp with ajustable voltage reference
 

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