I had first heard and read about the current controlled voltage source(ICVS) amplifier back in the engineering class but I had never chance to dwell deeper into this and other types of negative feedback circuits, what and where they can be applied. Earlier, I wrote about the Voltage-Controlled Voltage Source (VCVS) amplifier in my diary post on the non-inverting amplifier designed with BJT transistors. I believe VCVS amplifiers designed with op-amps are circuits most of us are familiar with.
Current controlled Voltage Source(ICVS) amplifier also known as transresistance amplifier is one type of negative feedback amplifier in which the input is a current source and the output is voltage and the output voltage varies with the input current.
Mathematically,
\[ v_{out} = -i_{in}R_f \]
The following is circuit diagram of ICVS amplifier built with LM538 amplifier.
%20Amplifier.png "Current Controlled Voltage Source (ICVS) Amplifier")
The variable resistor or POT RV1 can be tuned from 0 to 5kohm. The input signal is 1mA 1khz signal and when the potentio meter or the negative feedback resistor is 5kohm the output voltage is (-)5V peak to peak. The negative sign indicates that the signal is inverted. This can be easily derived from the equation above.
\[ v_{out} = =(-) i_{in}R_f = (-) 1mA \times 5kohm = (-)5V_{pp} \]
The input current and the output voltage waveform of this Current Controlled Voltage Source (ICVS) Amplifier circuit when the feedback resistor is 5kohm is shown below.
When the feedback resistor is almost 0 ohm then waveforms of the input current and output voltage is shown below.
Example Application of ICVS amplifier or Transimpedance amplifiers (TIAs) :
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Using a transimpedance amplifier followed by a voltage buffer.
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Using BJTs or MOSFETs arranged so that a current input controls the voltage across another stage.
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Found in some analog signal conditioning circuits, like sensors, ADC input interfaces, etc.
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