Voltage Regulator

Thread Starter

Vinny_P

Joined Jan 27, 2008
3
Hey all,

I have a circuit that has 11.15VDC offset which I would like to remove. The circuit is solely DC (no AC component). Someone told me I can use a voltage regulator to remove the offset therefore my read out will be between 0 - 5VDC. Can someone please shed some light on this issue.

I was thinking of using the summing opamp circuit to remove the offset. But the voltage regualtor method is interesting to me.

Furthermore, I was also thinking of having a zener diode with a avalanche voltage of 11.15V in series with a resistor and have the read out on the resistor.

Thank you,
Vinny P
 

SgtWookie

Joined Jul 17, 2007
22,201
Do you have a schematic that you could post?

.jpg or .png would be the preferred format.
 

scubasteve_911

Joined Dec 27, 2007
1,202
You cannot use a typical linear regulator, since it is designed for a specific output voltage. If it were a 5V regulator, then it will not behave correctly below 5V+dropout.

It really depends on what you are driving with your intended 0-5V signal. If it is a very high impedance load, then you can use a simple voltage divider to scale your 11.15V down. If you need to drive more of a load, then you can add a voltage follower. Furthermore, if you don't want to use a voltage divider, you can set up two inverting amplifiers to give the needed gain to convert your 11.15V down to 5V. This would be a good route if your signal has a very high source impedance and if you have a bipolar supply.

Steve
 

Thread Starter

Vinny_P

Joined Jan 27, 2008
3
I'm using a AD590 which will produce the current accross a load Resistor that will give the input to the ADC of an MCU.

The load accross the resistor will vary from 11.15VDC to 16.15VDC but I want it to be from 0-5VDC.

I simply want to remove the 11.15VDC offset. I beleive using an opamp it is possible (suming sircuit). However, someone did mention a voltage regualtor would be a good alternative.

Secondly I can't have a voltage divider on the 11.15VDC as I want to eliminate it completly.

Hope some one can help,
Vinny P

The following images may help.
http://img299.imageshack.us/my.php?image=2301082317qn7.jpg
http://img180.imageshack.us/my.php?image=2301082316nf6.jpg
 

Thread Starter

Vinny_P

Joined Jan 27, 2008
3
Hey Guys,


I decided to use the difference amp with unity gain utilizing the LM317L op amp due to budget reasons.

Will let you know how it went. :)

Thank you all... it is much appreciated,
Vinny P
 
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