Towards Realization of a Low-Voltage Class-AB VCII with High Current Drive Capability

Abstract

In this paper, the implementation of a low-voltage class AB second generation voltage conveyor (VCII) with high current drive capability is presented. Simple realization and good overall performance are the main features of the proposed circuit. Proper solutions and techniques were used to achieve high signal swing and high linearity at Y, X and Z ports of VCII as well as low-voltage operation. The operation of the proposed VCII was verified through SPICE simulations based on TSMC 0.18 µm CMOS technology parameters and a supply voltage of ±0.9 V. The small signal impedance values were 973 Ω, 120 kΩ and 217 Ω at Y, X and Z ports, respectively. The maximum current at the X port was ±10 mA with maximum total harmonic distortion (THD) of 2.4% at a frequency of 1 MHz. Considering a bias current (IB) of 29 µA and output current at the X port (IX) of 10 mA, the current drive capability (IX/IB) of about 345 was achieved at the X port. The voltage swing at the Z port was (−0.4, 0.4) V. The THD value at the Z port for an input signal with 0.8 V peak-to-peak value and frequency of 1 MHz was 3.9%. The total power consumption was 0.393 µW.

A Survey on Current-Mode Interfaces for Bio Signals and Sensors

“…An ideal second-generation voltage conveyor is nothing more than the dual active circuit block of the CCII [ 44 ]. This block is finding increasing applications as an alternative to the well-known voltage-mode circuit and the CCII itself [ 32 , 34 , 35 , 36 , 37 , 38 , 39 , 41 , 43 , 52 , 56 ]. As for the CCII, the information in a VCII is carried both by currents and voltages, but the VCII is equipped with both an input and an output voltage port.…”

“…The main current-mode analog blocks are the second-generation current conveyor (CCII) and its dual, the second-generation voltage conveyor (VCII). These blocks have been successfully applied to the realization of a variety of analog signal processing functions [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. For example, in [ 31 ] a current-mode full-wave bridge rectifier has been developed; in [ 32 , 40 , 42 ] the realization of various filter functions using VCII is shown; and in [ 33 , 53 ] current-mode oscillators are described.…”

“…An example is given in [ 34 ], which shows that the minimum number of components to realize an RC sinusoidal oscillator is significantly lower if VCII is used as an active block instead of an operational amplifier. On the other hand, a suitable internal design, at transistor level, is mandatory to reduce the effect of parasitic components, as discussed in [ 37 , 54 ]. For these reasons, the presented work aims to give a review of some of the proposed solutions using these active blocks, the CCII and the VCII, providing a comparison between these circuits and the traditional solutions that use the voltage-mode approach so as to highlight the main benefits of the current-mode approach.…”

Influence of Modifications Related to Safe Operating Area Demands on Operation of a Specialized Medium/High-Voltage Unity-Gain Buffer

“…Another set of adaptations to the source follower architecture is voltage conveyors (VC). Two implementations of second-generation VCs are introduced in [14,15]. Again, these modifications are focused on improving different operation parameters than in the case of the buffer scrutinized in this paper.…”