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# Differential Current Voltage Converter

IP.com Disclosure Number: IPCOM000087027D
Original Publication Date: 1976-Dec-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 34K

IBM

## Related People

Crauwels, GL: AUTHOR

## Abstract

The above circuit has a very low (essentially zero) input impedance on both of its inputs and will produce a voltage representative, by its The above circuit has a very low (essentially zero) input impedance on both of its inputs and will produce a voltage representative, by its magnitude and polarity, of the difference between the two input currents.

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Differential Current Voltage Converter

The above circuit has a very low (essentially zero) input impedance on both of its inputs and will produce a voltage representative, by its The above circuit has a very low (essentially zero) input impedance on both of its inputs and will produce a voltage representative, by its magnitude and polarity, of the difference between the two input currents.

A current control source 1, which may be an analog-type sensor is directly connected to the inverting input of an operating amplifier 3 whose output voltage on line 4 is fed back through a resistor 5 to its input from control 1. A second current control 2 is connected to the inverting input of another operating amplifier 6 having its output signal fed back to its input connected to control 2 through a resistor 7. The direct input of amplifier 6 is connected to a reference voltage level through a resistor 8. The output of amplifier 6 is also connected through a resistor 9 to the inverting input of amplifier 3 and the current control 2 is connected through a resistor 10 to the direct input of amplifier 3.

In this circuit, if no current is called for by controls 1 and 2, the outputs of amplifiers 3 and 6 are theoretically at zero since the amplifiers receive no input. When control 1 draws current, the current will be supplied through resistor 5 which drops the voltage at the inverting input. The output of amplifier 3 will rise correspondingly to return the input to normal so that the output voltage on line 4 will be proportional to the current through current control 1.

When current is drawn by current control 2, amplifier 6 acts in the same manner as described above for amplifier 3 to put its output voltage at a leve...