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# Reference Voltage Stabilizer

IP.com Disclosure Number: IPCOM000074351D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 26K

IBM

## Related People

Ortloff, JE: AUTHOR

## Abstract

This interactive circuit is used to make two normally independent sources mutually dependent. The circuit is of particular value in digital-to-analog converter circuits where positive and negative reference voltages are required to be exactly equal but of opposite polarity.

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Reference Voltage Stabilizer

This interactive circuit is used to make two normally independent sources mutually dependent. The circuit is of particular value in digital-to-analog converter circuits where positive and negative reference voltages are required to be exactly equal but of opposite polarity.

Two reference supplies 1 and 2 are remote sensed at their reference distribution buses 3 and 4. The voltage divider consisting of equal value resistors R1 and R2, provides an error signal to the input of operational amplifier A1, if +REF Bus not= -(-REF Bus). The operational amplifier will then provide a plus or minus output, resulting in a current flow through either R3 and R4. The resultant voltage drop across R4 will cause the output voltage of +REF Bus to change to -(-REF Bus) + the loop gain error, which is very small. Assuming Aol = 10/5/

R1 = R2 = R3 = 10O0 ohms R4 = 10 ohms

Loop Gain = Aol x R4 over R3 x R1 over R1+R2

Loop Gain = 10/5/ x 10 over 1000 x 1 over 2 Loop Gain = 500.

With a loop gain of 500, a variation of 1 volt in the power supplies themselves will result in only a 2 millivolt error in the desired relationship.

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