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

AI Thread 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. Suggestions include using op-amps designed for dual supply operation, such as the 741 or TL08x series, which can handle both positive and negative voltages. The best results are noted when summing only on the inverting inputs, with a differential amplifier configuration recommended. The conversation highlights the need for flexibility in voltage handling for the specified circuit.
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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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