Synthesis of Analog Circuits Using Only Voltage and Current Followers as Active Elements

Abstract

There has been considerable interest in recent technical literature on the use of only unity gain cells (i.e. unity gain voltage followers (VF) and unity gain current followers (CF)) as alternatives to other more complex building blocks in the design of analog circuits. This has been possible due to the advances made in IC technology. It is possible to design VFs and CFs providing wider bandwidth, lower power consumption and simpler architectures as compared to other more complex building blocks. Moreover, using CFs and VFs it becomes possible to design all the four controlled sources in an open loop arrangement without encountering the gain-bandwidth-conflicts. These advantages have stimulated considerable interest in the use of VFs and CFs in a variety of linear as well as non-linear applications over the past two decades. Simultaneously, significant work has also been done on improving the design of VFs and CFs themselves for both bipolar and CMOS technologies. This chapter presents a brief account of some prominent works done on the analog circuit design using VFs and CFs together with the design of VFs and CFs themselves.