Author: ESTEBAN TLELO CUAUTLE

A novel CMOS exponential transconductor operating in weak inversion

ROGELIO DE JESUS PEREGRINA ALEJANDRO DIAZ SANCHEZ ESTEBAN TLELO CUAUTLE JOSE MIGUEL ROCHA PEREZ (2008)

A novel CMOS exponential transconductor which employs only three NMOS transistors operating in weak inversion, is presented. The main advantage of the proposed circuit is its wide range of exponential behaviour, which reaches up to five decades of current range, and above 10 µA to an input voltage range of 800 mV. The physical realisation is achieved in two forms: in the first one, the circuit is implemented with discrete MOS transistor arrays by CD4007 series; in the second one, the circuit is fully integrated in a 0.5 µm CMOS standard process. Simulated and experimental results of the proposed exponential transconductor are also presented.

Article

Analogue circuits CMOS circuits Exponential circuits Weak inversion circuits Transconductors CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

Simulation of a parallel mechanical elbow with 3 DOF

JOSE RAFAEL MENDOZA VAZQUEZ ESTEBAN TLELO CUAUTLE J LUIS VAZQUEZ GONZALEZ APOLO ZEUS ESCUDERO URIBE (2009)

The kinematics simulation and modeling of a mechanical elbow of 3 degrees of freedom, is introduced by highlighting the main features of the mechanism related to the design criteria. The mechanical elbow is used as a transhumeral prosthetic part, and it has been built as a parallel topology consisting of electric linear actuators and universal joints. The parallel mechanism has 4 legs. 3 are electric linear actuators, and the fourth leg provides mechanical support for the whole structure and holds a DC Motor that performs the action of gripping objects. Furthermore, this paper shows the inverse kinematics for the elbow by geometric methods, and the MatLab‐simulation results show the workspace of the movement and the ability of the mechanical elbow to replicate the movements of a biological one.

Article

Kinematics Modeling Simulation Robot kinematics CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

On the relation between the number of scrolls and the lyapunov exponents in PWL-functions-based η-scroll chaotic oscillators

RODOLFO TREJO GUERRA ESTEBAN TLELO CUAUTLE JESUS MANUEL MUÑOZ PACHECO CARLOS SANCHEZ LOPEZ (2010)

A challenge in the physical design of η-scroll attractors is to generate a large number of scrolls. However, an open question is: Does the large number of scrolls determine a better chaotic behavior? We present a partial answer to this question by computing the Lyapunov exponents for piecewise-linear (PWL) functions based on η-scroll third order chaotic oscillators, namely: Zhong modified Chua's circuit, Yu modified Chua's circuit, saturated function series based chaotic oscillator, and generalized Chua's circuit with saw-tooth function. Three different integration methods (forward Euler, fourth order Runge Kutta and Matlab ODE 45) are used in order to show that the positive Lyapunov exponent is not significantly incremented in relation with the number of scrolls.

Article

Lyapunov exponent Multiscroll oscillators Scroll number Chaos CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA ELECTRÓNICA

N-scroll chaotic attractors from saturated function series employing CCII+s

CARLOS SANCHEZ LOPEZ RODOLFO TREJO GUERRA JESUS MANUEL MUÑOZ PACHECO ESTEBAN TLELO CUAUTLE (2010)

The generation of n-scroll chaotic attractors by using saturated nonlinear function series (SNFS) realized with positive-type second generation current conveyors (CCII+s), is introduced. The nonlinear dynamical system is expressed by a third-order differential equation and to carry out numerical simulations, SNFS are ideally modeled by using staircase functions. Therefore, numerical simulations are introduced to approximate the swings, widths, breakpoints and equilibrium points of the n-scroll attractors by considering, as input variables: the dynamic range associated to active devices, gain of the nonlinear system and the number of scrolls. Therefore, its dynamical behavior is investigated in the state space. Besides, the CCII± is a versatile analog building block and it has been demonstrated to be very useful in several linear and nonlinear applications, since CCII-based implementations offer better performances that Opamps-based implementations in terms of accuracy and bandwidth. Therefore, the nonlinear system is synthesized with CCII+s to generate 3- and 4-scrolls. HSPICE simulations and experimental results are shown to verify the agreement on the behavior of the proposed circuit and the numerical simulations.

Article

Multiscroll chaotic attractor Saturated function series Current conveyor CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

Realization of multiscroll chaotic attractors by using current-feedback operational amplifiers

RODOLFO TREJO GUERRA ESTEBAN TLELO CUAUTLE CARLOS SANCHEZ LOPEZ JESUS MANUEL MUÑOZ PACHECO (2010)

Multiscroll chaotic attractors are physically implemented by using commercially available current-feedback operational amplifiers (CFOAs). The values of the circuit elements are obtained systematically by a proposed technique based in the saturation of the CFOA to create Piece- Wise Linear (PWL) functions. Herein the technique is verified by Spice simulations and in experimental form by using CFOAs to generate n-scroll attractors in a systematic way. Lyapunov exponents are given to prove the chaotic behavior.

Se realiza la implementacion física de atractores caóticos de múltiples enrollamientos por medio del circuito comercial denominado amplificador operacional retroalimentado en corriente (CFOA). Los valores de los elementos del circuito son obtenidos sistemáticamente por medio de una técnica propuesta basada en la saturación del CFOA para generar funciones lineales a tramos (PWL functions). En este punto, la técnica es verificada por medio de simulaciones en Spice, así como de manera experimental utilizando CFOAs para generar atractores de n–enrollamientos de forma sistemática. Se presentan los exponentes de Lyapunov para corroborar el comportamiento caótico.

Article

n-scroll attractors Chua’s circuit Break point Lyapunov exponent CFOA PWL function Atractores n-enrollamientos Circuito de Chua Punto de quiebre Exponente de Lyapunov Función lineal a tramos CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA ELECTRÓNICA

Synthesis of CCII-s by superimposing VFs and CFs through genetic operations

ESTEBAN TLELO CUAUTLE DAVID MORO FRIAS CARLOS SANCHEZ LOPEZ MIGUEL AURELIO DUARTE VILLASEÑOR (2008)

It is introduced a new genetic algorithm to synthesize the negative-type second generation current conveyor (CCII-) by superimposing a voltage follower (VF) with a current follower (CF). First, the VF and CF are described by binary genes. Second, the gene CF is inverted, rigth-shifted and multiplied (AND operation) with the gene VF to verify that both genes can be superimposed to synthesize the CCII-. Finally, some synthesized CCII-s are presented which electrical characteristics are measured using HSPICE and standard CMOS technology of 0.35 μm.

Article

Evolutionary electronics Circuit synthesis Current conveyor Nullor CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA CIRCUITOS INTEGRADOS

N-scroll chaotic attractors from saturated function series employing CCII+s

Carlos Sanchez Lopez RODOLFO TREJO GUERRA JESUS MANUEL MUÑOZ PACHECO ESTEBAN TLELO CUAUTLE (2010)

The generation of n-scroll chaotic attractors by using saturated nonlinear function series (SNFS) realized with positive-type second generation current conveyors (CCII+s), is introduced. The nonlinear dynamical system is expressed by a third-order differential equation and to carry out numerical simulations, SNFS are ideally modeled by using staircase functions. Therefore, numerical simulations are introduced to approximate the swings, widths, breakpoints and equilibrium points of the n-scroll attractors by considering, as input variables: the dynamic range associated to active devices, gain of the nonlinear system and the number of scrolls. Therefore, its dynamical behavior is investigated in the state space. Besides, the CCII± is a versatile analog building block and it has been demonstrated to be very useful in several linear and nonlinear applications, since CCII-based implementations offer better performances that Opamps-based implementations in terms of accuracy and bandwidth. Therefore, the nonlinear system is synthesized with CCII+s to generate 3- and 4-scrolls. HSPICE simulations and experimental results are shown to verify the agreement on the behavior of the proposed circuit and the numerical simulations.

Article

Multiscroll chaotic attractor Saturated function series Current conveyor CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA ELECTRÓNICA

Automatic synthesis of electronic circuits using genetic algorithms

Síntesis automática de circuitos electrónicos usando algoritmos genéticos

ESTEBAN TLELO CUAUTLE MIGUEL AURELIO DUARTE VILLASEÑOR CARLOS ALBERTO REYES GARCIA GERARDO REYES SALGADO (2007)

An automatic synthesis method based on the application of genetic algorithms (GAs) is described for the synthesis of voltage followers (VFs), which are designed using CMOS integrated circuit technology of 0.35μm. It is shown the usefulness of the nullor element to model the ideal behavior of the VF, and to codify its topology using a chromosome which is divided into four genes: gene of small-signal (genSS), gene of synthesis of the MOSFET (genSMos), gene of bias (genBias), and gene of synthesis of current mirrors (genCM); this last one to synthesize ideal current sources used in the biasing of the circuits with CMOS current mirrors.

The proposed synthesis method has been programmed in MatLab, and it uses T-SPICE to evaluate the fitness of the VFs at the transistor level of abstraction. In this manner, the method selects the more appropriated VFs by elitism. Finally, it is shown the behavior of the GA to synthesize practical VFs. As a result, it is shown the synthesis of eight CMOS compatible VFs, and their applications are briefly discussed.

Se describe un método de síntesis automática basado en la aplicación de algoritmos genéticos (GAs) para la síntesis de seguidores de voltaje (VFs), los cuales son diseñados usando tecnología CMOS de circuitos integrados de 0.35μm. Se demuestra la utilidad del elemento anulador para modelar el comportamiento ideal del VF, y para codificar su topología usando un cromosoma que es dividido en cuatro genes: gen de pequeña señal (genSS), gen de síntesis del MOSFET (genSMos), gen de polarización (genBias), y gen de síntesis de espejos de corriente (genCM); este último para sintetizar las fuentes de corriente ideales utilizadas en la polarización de los circuitos por espejos de corriente CMOS.

El método de síntesis propuesto se ha programado en MatLab, y usa T-SPICE para evaluar la aptitud de los VFs en el nivel de abstracción de transistor. De esta manera, el método selecciona los VFs más apropiados por elitismo. Finalmente, se muestra el comportamiento del GA para sintetizar VFs prácticos. Como resultado, se muestra la síntesis de ocho VFs compatibles con CMOS, y sus aplicaciones se discuten brevemente.

Article

Evolutionary electronics Circuit synthesis Voltage follower Nullor Electrónica evolutiva Síntesis de circuitos Seguidor de voltaje Anulador CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

A novel CMOS exponential transconductor operating in weak inversion

ROGELIO DE JESUS PEREGRINA ALEJANDRO DIAZ SANCHEZ ESTEBAN TLELO CUAUTLE JOSE MIGUEL ROCHA PEREZ (2008)

A novel CMOS exponential transconductor which employs only three NMOS transistors operating in weak inversion, is presented. The main advantage of the proposed circuit is its wide range of exponential behavior, which reaches up to five decades of current range, and above 10 µA to an input voltage range of 800 mV. The physical realization is achieved in two forms: in the first one, the circuit is implemented with discrete MOS transistor arrays by CD4007 series; in the second one, the circuit is fully integrated in a 0.5 µm CMOS standard process. Simulated and experimental results of the proposed exponential transconductor are also presented.

Article

Analogue circuits CMOS circuits Exponential circuits Weak inversion circuits Transconductors CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA

Experimental synchronization of multiscroll chaotic attractors using current-feedback operational amplifiers

Víctor Hugo Carbajal Gómez ESTEBAN TLELO CUAUTLE RODOLFO TREJO GUERRA CARLOS SANCHEZ LOPEZ Jesús Manuel Muñoz Pacheco (2011)

We present the experimental synchronization of two multiscroll chaotic attractors realized with current-feedback operational amplifiers. The synchronization is performed by applying Hamiltonian forms and observer approach. An application example is provided through the implementation of a master-slave communication system for chaotic encryption.

Article

Multiscroll Hamiltonian Forms Syncronization Secure Communication Amplifier CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ELECTRÓNICA ELECTRÓNICA