Automatic Synthesis of VFs and VMs by Applying Genetic Algorithms

Abstract

An automatic synthesis method is introduced to design voltage followers (VFs) and voltage mirrors (VMs) by performing evolutionary operations. It is shown that the nullor element is useful to introduce a new genetic representation to codify the behavior of the VF by a chromosome divided by four genes: small-signal (genSS), synthesis of the nullor by MOSFET (genSMos), bias (genBias), and synthesis of current mirrors (genCM). Further, it is shown that the behavior of the VM can be codified by evolving the chromosome of the VF. The proposed synthesis method uses SPICE to evaluate the fitness of the VF and VM. Finally, we show the synthesis of several VFs and VMs which are designed using standard CMOS technology of 0.35 µm. The applications and evolution of the VF and VM to synthesize more complex devices such as current conveyors (CCs) and inverting CCs are briefly discussed.

Binary Genetic Encoding for the Synthesis of Mixed-Mode Circuit Topologies

“…As already shown in [26], the BGE of the VF can be performed from a topology consisting of nullators (O). Every element O is joined with a norator (P), leading to the combinations shown in Fig.…”

“…In this work, we introduce the automatic synthesis of mixed-mode active devices, such as current conveyors and CFOAs, using a simple genetic algorithm [26,28]. That way, in Sect.…”

Behavioral Modeling of Mixed-Mode Integrated Circuits

“…All kinds of current conveyors work in mixed-mode and basically they are composed of unity gain cells (Soliman, 2009;Tlelo-Cuautle, Duarte-Villaseñor & Guerra-Gómez, 2008), which can be superimposed (Tlelo-Cuautle, Moro-Frias & Duarte-Villaseñor, 2008) to generate different kinds of active devices (Biolek et al, 2008), all of them useful for analog signal processing applications. Among the unity gain cells, the voltage mirror (Tlelo-Cuautle, Duarte-Villaseñor & Guerra-Gómez, 2008) and current mirror can be modeled by using nullators and norators (Tlelo-Cuautle, Sánchez-López, , but also they have the pathological representation introduced in (Saad & Soliman, 2010), and they can be used to model the behavior of active devices with inverting characteristics. Although the current conveyor is a mixed-mode device, it can be used to implement voltage-mode circuits such as active filters (Chen, 2010;Maheshwari et al, 2010).…”

Realizations of Grounded Negative Capacitance Using CFOAs

“…Several highperformance VFs have been reported in the literature, e.g. in [16,27]. The CFOA can also be modeled at a higher level of abstraction, (using Verilog-A or SNAP [22]) to perform its symbolic/behavioral modeling [26].…”