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

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SUMMARY

This discussion focuses on methods to shift a 0-5V signal from a digital-to-analog converter (DAC) to a -2.5 to 2.5V range. The recommended approach involves using an op-amp voltage difference amplifier, requiring a bipolar power supply of +5V and -5V. Alternative solutions include using a large capacitor in the signal line or a resistor divider connected to a negative supply voltage, especially for audio signals. The context of the application is a laser scanner system utilizing mirror galvanometers.

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  • Understanding of op-amp configurations, specifically voltage difference amplifiers.
  • Knowledge of bipolar power supply requirements for analog circuits.
  • Familiarity with unipolar to bipolar conversion techniques.
  • Basic principles of signal processing, particularly for audio applications.
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  • Research "Op-Amp Voltage Difference Amplifier Design" for practical implementation details.
  • Explore "Bipolar Power Supply Design" to understand requirements for analog circuits.
  • Study "Unipolar to Bipolar Converter Circuits" for alternative conversion methods.
  • Investigate "Using Capacitors in Signal Processing" for filtering and signal conditioning techniques.
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Electronics engineers, audio signal processing specialists, and anyone involved in designing circuits for DAC applications, particularly in laser scanning systems.

bassplayer142
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Shifting 0--5V signal to -2.5--2.5V

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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In a op-amp voltage difference amplifier, you could subtract 2.5V from the input:

diffa2.gif
 

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For this setup I will need to supply a positive voltage on pin 7 and a negative one on pin 4 right? thanks
 


bassplayer142 said:
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.
 
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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.com/design-a-unipolar-to-bipolar-converter-for-a-unipolar-voltage-output-dac/"
 
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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?
 


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!
 


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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