Low Voltage, Low Power CMOS Current Conveyors (repost)

Research in analog integrated circuits has recently gone in the direction of low-voltage (LV), low-power (LP) design, especially in the environment of portable systems where a low supply voltage, given by a single-cell battery, is used. These LV circuits have to show a reduced power consumption to maintain a longer battery lifetime as well. In this area, traditional voltage-mode techniques are going to be substituted by the current-mode approach, which has the recognized advantage to overcome the gain-bandwidth product limitation, typical of operational amplifiers. Then they do not require high voltage gains and have good performance in terms of speed, bandwidth and accuracy. Inside the current-mode architectures, the current-conveyor (CCII) can be considered the basic circuit block because all the active devices can be made of a suitable connection of one or two CCIIs. CCII is particularly attractive in portable systems, where LV LP constraints have to be taken into account. In fact, it suffers less from the limitation of low current utilisation, while showing full dynamic characteristics at reduced supplies (especially CMOS version) and good high frequency performance. Recent advances in integrated circuit technology have also highlighted the usefulness of CCII solutions in a large number of signal processing applications. In Low Voltage, Low Power CMOS Current Conveyors, the authors start by giving a brief history of the first and second generation CC.