0.1 Volts output voltage regulator

[john]

Hi,

I am looking for a +/- 0.1 volts output voltage regulator. I have
+/- 5 volts input. Any advice!

Thanks
John

 

[Spehro Pefhany]

Hi,

I am looking for a +/- 0.1 volts output voltage regulator. I have
+/- 5 volts input. Any advice!

Thanks
John

Voltage dividers and op-amp buffers will do it, conceptually anyway,
but the details depend on the load characteristics.
Best regards,
Spehro Pefhany

 

[Tom Bruhns]

Hi,

I am looking for a +/- 0.1 volts output voltage regulator. I have
+/- 5 volts input. Any advice!

Thanks
John

You didn't mention what sort of accuracy and regulation you need, nor
what the load current is (static and dynamic). If you use a linear
regulator, the efficiency will be awful: 100%*0.1/5 = 2%, maximum.
But if your load current is low, that may not be an issue. In fact,
if the load current is low, just use a dual op amp, one side connected
as a unity gain follower and the other as a unity gain inverter,
driven from the follower output. You may be able to do OK with just a
resistive divider from your 5V to generate the 0.1V to put into the
follower. For higher load current, consider an LT3080 for the
positive side. If what you want is really a voltage reference, use a
precision 1.24V reference, or the like, and divide that down and
buffer it with a low-drift (and perhaps low offset) op amp follower.

Cheers,
Tom

 

[john]

Hi,

The output current is 0.1A.
Regards,
John

 

[Phil Allison]

"john"

I am looking for a +/- 0.1 volts output voltage regulator. I have
+/- 5 volts input. Any advice!

** You can use LM317s and LM337s with each adjust terminal referenced to the
opposite 5 volt rail.




...... Phil

 

[Phil Allison]

"Spehro Pefhany"
"Phil Allison"

So a 1% shift in either 5V line changes the opposite 0.1V output
voltage by 50% wrt ground?

** The OP stated he had +/- 5 volt rails - so who am I to doubt him
.......

Plus - I only posted an idea he CAN use if he likes.

BTW:

The regulation of 7805 / 7905 type ICs is way better than 1% under near
constant load conditions, as is the case with the majority of circuits.

Setting up precise +/- 1.05 volt refs for 317 / 337s perfectly possible
too.



..... Phil

 

[Joerg]

Hi,

I am looking for a +/- 0.1 volts output voltage regulator. I have
+/- 5 volts input. Any advice!

One way would be to use an opamp plus pnp/npn followers at the output to
get to your 100mA. Use the whole thing as a follower. A positive and a
negative reference set, say, +/-1.24 volts. You can use two TLV431. Or
if it has to be really cheap take the TL431 at +/-2.5V. Divide that down
to +/-0.1V via resistors and, voila, there is your regulator.

Add overload protection if needed.

 

[Winfield Hill]

You didn't mention what sort of accuracy and regulation you need, nor
what the load current is (static and dynamic). If you use a linear
regulator, the efficiency will be awful: 100%*0.1/5 = 2%, maximum.
But if your load current is low, that may not be an issue. In fact,
if the load current is low, just use a dual op amp, one side connected
as a unity gain follower and the other as a unity gain inverter,
driven from the follower output. You may be able to do OK with just a
resistive divider from your 5V to generate the 0.1V to put into the
follower. For higher load current, consider an LT3080 for the
positive side. If what you want is really a voltage reference, use a
precision 1.24V reference, or the like, and divide that down and
buffer it with a low-drift (and perhaps low offset) op amp follower.

Cheers,
Tom

The LT3080 is definitely the way to go, for +0.1 volt out.
It's adjustable down to zero (0.0) volts. What's not to
like? Well, OK, there is a required minimum load current
of 500uA max, to operate the circuit.

 

[Joerg]

]

The LT3080 is definitely the way to go, for +0.1 volt out.
It's adjustable down to zero (0.0) volts. What's not to
like? Well, OK, there is a required minimum load current
of 500uA max, to operate the circuit.

Thanks for the post, Win. The setup of my googlegroups "kill all but
good guys" has been validated. Not seeing you post in a while had me
concerned that I had a defect in my "good guys" file.

Hmm, why don't you just filter the domain of the poster like I do? Dumps
most Google spam but not Win's post.

 

[Joerg]

The LT3080 is definitely the way to go, for +0.1 volt out.
It's adjustable down to zero (0.0) volts. What's not to
like? Well, OK, there is a required minimum load current
of 500uA max, to operate the circuit.

But John won't get his negative range then. Plus it's an LDO which I
won't trust nomore never no more. AFAIU he wants it adjustable between
-100mV and +100mV. I'd just do the usual ref-opamp-pnp/npn thing.

Just to be a nitpicker here, I wonder how one would ascertain a 500uA
load current at 0.0V ))

 

[Joerg]

Ever hear of a negative supply rail ?

Can be done. Who knows, then the neg rail comes before the pos rail ...
phsst ... BANG.

 

[Joerg]

You have way too much "phsst ... BANG" in your life ;-)

It's more on the BANG side by now ;-)

 

[Joerg]

10K to -5V supply

Yes, if there's substrate diodes you could probably do that.

Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

 

[whit3rd]

I am looking for a +/-  0.1 volts output voltage regulator. I have
+/-  5 volts input. Any advice!

The usual voltage regulators are dedicated current source or
current sink elements (never both). If you need a two-quadrant
(source and sink) current characteristic, linear regulators will not
do, you need a power op amp, or at least polarity-setting
switches.