Apparatus and method for converting differential voltage to fully balanced currents

摘要

The apparatus for converting a differential input voltage to two fully balanced output currents is achieved by providing a common mode control circuit of a simplified circuit construction to an operational transconductance amplifier. The apparatus includes an operational transconductance amplifier that is comprised of an OTA input section for converting two input voltages of the differential input voltage to a pair of interim output currents and an OTA output section for converting the interim output currents to the output currents, and a common mode controlling circuit for providing a control voltage to the OTA. The common mode control circuit is comprised of a substantially same circuit construction as the OTA output section and generates two output control currents based on the interim output currents from the OTA input section and the two output control currents from the common mode control circuit are summed and kept to be substantially zero in order to control the output currents from the OTA output section fully balanced.