Voltage-to-current (V–I) converter use case: In what scenario is a V–I converter preferred—when the application demands an output load current directly controlled by which input quantity?

Introduction / Context:
Voltage-to-current (V–I) converters, often implemented with op-amps, OTAs, or dedicated ICs, generate an output current that is a defined function of an input voltage. Their hallmark is regulating current through a load independently of load resistance variations within compliance limits, which is crucial in sensor excitation and current-loop signaling.

Given Data / Assumptions:

• We require a load current proportional to a command quantity.
• Load resistance may vary or be unknown.
• The current must follow a linear relation such as Iload = Vin / Rset.
• Supply rails and voltage compliance are adequate for the desired current.

Concept / Approach:
A V–I converter senses the voltage across a reference resistor and drives the output so that the measured current equals a target value derived from the input voltage. In transconductance terms, it realizes Iout = Gm * Vin, where Gm is defined by circuit elements. This ensures consistent current delivery despite load resistance changes, provided the output voltage stays within compliance.

Step-by-Step Solution:

Verification / Alternative check:
Compare with a voltage source feeding a resistor: current then depends on Rload. The V–I converter, by contrast, actively adjusts voltage to hold current constant according to the input voltage command.

Why Other Options Are Wrong:

Common Pitfalls:
Ignoring compliance voltage, neglecting sense resistor accuracy, and overlooking thermal limits lead to current errors or saturation.

Final Answer:
input voltage