Overview

The information processed by lumped electric networks can be represented by either the nodal voltages or branch currents of the networks. The former are referred to as voltage-mode circuits whereas the latter are known as current-mode circuits. Together, they provide a complete characterization of the behavior of the networks.

Voltage-mode circuits have received a much broader attention and found a much wider range of applications as compared with their current-mode counterparts despite the fact that the concept of ideal current-mode circuits, similar to that of ideal voltage-mode circuits, emerged approximately 40 years ago [1, 2]. This is reflected by a handful monographs on current-mode circuits [3 8] but countless texts on voltage-mode circuits. The reasons for such a popularity that voltage-mode circuits have been enjoying can be summarized as follows : (i) The nodal voltage of electric networks can be measured conveniently using voltmeters without modifying the topology and affecting the operation of the networks. On the contrary, the measurement of the branch current of the networks are less convenient and often requires a change of the configuration of the networks or additional circuitry. (ii) The infinite impedance looking into the gate of MOS transistors makes these devices an ideal choice for the realization of voltage-mode circuits, especially in cascade configurations, such as multi-stage voltage amplifiers. (iii) The ease to obtain a high voltage gain of voltage-mode circuits using techniques such as cascodes and regulated cascodes. (iv) High supply voltages available in the past such that low-voltage design was not...