Shifting 0--5V signal to -2.5--2.5V


by bassplayer142
Tags: 2525v, shifting, signal
bassplayer142
bassplayer142 is offline
#1
Jul16-10, 10:09 AM
P: 422
I have a DAC coming from my micro with a signal that will vary anywhere from 0-5Volts. What are my options of shifting that down so I can get a -2.5 -- 2.5V swing? Thanks!
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waht
waht is offline
#2
Jul16-10, 11:23 AM
P: 1,636
In a op-amp voltage difference amplifier, you could subtract 2.5V from the input:

bassplayer142
bassplayer142 is offline
#3
Jul16-10, 11:57 AM
P: 422
For this setup I will need to supply a positive voltage on pin 7 and a negative one on pin 4 right? thanks

uart
uart is offline
#4
Jul16-10, 12:07 PM
Sci Advisor
P: 2,751

Shifting 0--5V signal to -2.5--2.5V


Quote Quote by bassplayer142 View Post
For this setup I will need to supply a positive voltage on pin 7 and a negative one on pin 4 right? thanks
Yes, about +5 / -5 volts DC at a minimum.

There may be a much simpler solution but without a more detailed description of the nature of the signal then you mightn't get it.
AdrianN
AdrianN is offline
#5
Jul16-10, 12:15 PM
P: 8
Yes, you need a bipolar power supply. Your circuit is a unipolar to bipolar converter. If interested, I have an article about this type of circuit here:

Design a Unipolar to Bipolar Converter for a Unipolar Voltage Output DAC
http://masteringelectronicsdesign.co...ge-output-dac/
schip666!
schip666! is offline
#6
Jul16-10, 12:35 PM
P: 595
From your name, bassplayer, I'm thinking that you have an audio signal?

If it is over 10Hz or so, presuming that the destination is biased around 0v, you might be able to just put a big capacitor in the signal line. You might also get away with using a resistor divider to a negative supply voltage without bothering with an Op-Amp.

What's your actual application?
bassplayer142
bassplayer142 is offline
#7
Jul18-10, 09:44 AM
P: 422
Actually I'm working on a laser scanner system for light show with some mirror galvanometers. I don't have a datasheet on them or any type of function generator so having an easily adjustable supply will be great for finding the limits of operation. Thanks for all the posts, its been a great help!
schip666!
schip666! is offline
#8
Jul18-10, 01:30 PM
P: 595
Then they are pretty much just speaker voice coils, and a inline capacitor will do the trick. However you probably need more power than the PC output can push. Perhaps more than the PC headphone output too, but you could try that or a small powered speaker system for a start.


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