Can Any IC Handle V0 = V1 + V2 - (V3 + V4) Regardless of Voltage Polarity?

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SUMMARY

The discussion centers on finding an integrated circuit (IC) capable of performing the calculation V0 = V1 + V2 - (V3 + V4) without restrictions on voltage polarity. The LM324 is mentioned but is unsuitable due to its requirement that V1 + V2 must exceed V3 + V4. Participants recommend using dual supply operational amplifiers such as the 741 or TL08x series, which can handle both positive and negative voltage inputs effectively.

PREREQUISITES
  • Understanding of operational amplifier configurations
  • Knowledge of dual supply voltage operation
  • Familiarity with differential amplifier circuits
  • Basic principles of voltage summation and subtraction
NEXT STEPS
  • Research the specifications and applications of the 741 operational amplifier
  • Explore the TL08x series of operational amplifiers for dual supply configurations
  • Learn about differential amplifier design and its advantages in voltage calculations
  • Investigate biasing techniques for operational amplifiers to accommodate varying input voltages
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Electronics engineers, circuit designers, and hobbyists looking to implement voltage calculations in their projects using operational amplifiers.

Poptart
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Hi,

I've been having a bit of trouble finding a summer IC that can perform the following calculation:

V0 = V1 + V2 - (V3 + V4)

I found the LM324 which includes that calculation in its documentation, but it requires V1 + V2 > V3 + V4 since it's only got V+ and GND inputs. This requirement is a deal-breaker since my possible V0 can be either positive or negative.

In my circuit, V1-4 all can range from 0 to 100 mV. Does anyone know of a specific IC that would be able to meet these criteria?

Thanks for the help,
-Ben
 
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You can bias everything up by a known amount, or use pretty much any opamp made for dual supply operation. The good old 741, or any of the TL08x series come to mind.
 
You will get the best results if you sum only on the inverting inputs. U3 in the thumbnail is a standard differential amplifier configuration.

Bob S
 

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