A New Rail-to-Rail Second Generation Voltage Conveyor

Abstract

In this paper, a novel low voltage low power CMOS second generation voltage conveyor (VCII) with an improved voltage range at both the X and Z terminals is presented. The proposed VCII is formed by a current buffer based on a class AB regulated common-gate stage and a modified rail-to-rail voltage buffer. Spice simulation results using LFoundry 0.15 μm low-Vth CMOS technology with a ±0.9 V supply voltage are provided to demonstrate the validity of the designed circuit. Thanks to the class AB behavior, from a bias current of 10 µA, the proposed VCII is capable of driving 0.5 mA on the X terminal, with a total power consumption of 120 µW. The allowed voltage swing on the Z terminal is at least equal to ±0.83 V, while on the X terminals it is ±0.72 V. Both DC and AC voltage and current gains are provided, and time domain simulations, where the voltage conveyor is used as a transimpedance amplifier (TIA), are also presented. A final table that summarizes the main features of the circuit, comparing them with the literature, is also given.

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

“…In [17], a comparison between OA-based circuits and VCII-based circuits was drawn, showing that the problem of the cross-talk effect among inputs in a conventional OA-based non-inverting summing amplifier can be cancelled out using VCII. Literature survey shows the possibility of realizing various VCIIbased analog circuits such as filters, integrators, differentiators, rectifiers, and impedance simulators [16][17][18][19][20][21][22][23][24][25][26][27].…”

“…Literature survey shows that there are very few VCII circuits designed in class AB [25][26][27]30]; however, all of them suffer from poor current drive capability. In [25], a flipped voltage follower (FVF)-based VCII circuit was presented, which can provide an output current up to ±2 mA.…”

New simple transistor realizations of second‐ generation voltage conveyor

“…Nevertheless, due to the abovementioned disadvantages of the OPAMP, VCII seems to attract the attention of designers. The application areas of VCII such as voltage integrator, 7,8 transimpedance amplifier, 9 first‐ and second‐order filters, 10–12 differential capacitive sensor, 13 inductor simulator, 14 and full wave rectifier 15 play an active role in the literature.…”

“…Recently, a new CMOS realization of VCII with high performance is proposed employing 11 transistors and seven ideal current sources 7 . CMOS implementation of flipped voltage follower (FVF)‐based VCII consists of 16 transistors, and seven ideal current sources have been proposed in Barile et al 8 Barile et al 9 present rail‐to‐rail VCII employing 29 transistors, five ideal current sources, and two biasing voltage sources excepting DC supply voltages. As for another CMOS realization of VCII, it includes 10 transistors and four ideal current sources 10 .…”

“…CMOS realization of class AB VCII is made up of 12 transistors and four ideal current sources 22 . However, the main disadvantage of the circuits reported in previous studies 7–10,22 is that they have too many ideal current sources that should be implemented with many transistors. It should be noted that the ideal current sources used to set the direct current (DC) points in the circuits must either be provided with at least one transistor and a biasing voltage source for each current source or implemented with a single current source and a great number of copying transistors.…”