Voltage to current converter for high frequency applications

摘要

A fully integrated voltage-to-current converter consisting of a two-stage direct amplifier with an overall feedback network having an active differential current-to-voltage converter. The first stage of the two-stage direct amplifier is a voltage-to-voltage converter receiving an input voltage signal, and the second stage is a transconductance amplifier supplying an output current. In the overall feedback network, a voltage measure of the output current is applied to a differential amplifier which cancels out all DC components and amplifies only the AC components. The amplified AC components are fed back to the input. The feedforward gain of the two-stage direct amplifier and the feedback gain of the overall feedback network may be separately adjusted. The differential amplifier includes a local resistive feedback network such that the local gain of the differential amplifier is determined by resistor values and does not introduce any non-linear elements. The overall feedback network gain of the voltage-to-current converter may be adjusted without affecting the direct amplifier solely by varying the local resistive feedback network of the differential amplifier.