28631 - Foundations of Electronics for Automation T-1

Learning outcomes

This course is aimed at studying the operating principles and the main characteristics of the electronic devices and circuits used for the implementation of control systems for industrial automation. In particular, the topics dealt with in the course include the main circuits used for digital signal processing, signal acquisition and conversion, and interfacing with different types sensors.

Course contents

Electron Devices: Basics of electron device physics. Electric properties of metals, dielectrics, and semiconductors. Charge carriers: electrons and holes. P-type and n-type semiconductors. Junction diodes: basic principles, I/V characteristics, analytical and empirical models. Memory effects. Junction and diffusion capacitance. Breakdown. Zener diodes. Bipolar Junction Transistors: basic principles, Ebers-Moll analytical model. Equivalent circuits. Symplified models in different operation modes. Common-base and common Emitter I/V characteristics. n- and p-MOSFETs: basic principles, analytical models, I/V characteristics.

 

Analog circuits: single-phase rectifier, half-wave and full-wave. Limiters. Linearisation of elementary nonlinear bipoles.: nonlinear resistors and capacitors. Small-signal equivalent circuits of BJTs and MOSFETs. Physical and hybrid model parameters. High-frequency effects. Small-signal analysis of basic amplifying stages. Bias circuits. Thermal behaviour of transistor characteristics. Bias point stability. Coupling capacitors. DC coupling. Thermal drift. Offsets. Differential amplifiers: differential- and common-mode gain, CMRR. Basics of feedback theory. Ideal and nonideal operational Amplifiers. Elementary circuits based on OpAmp.

 

Digital circuits: Basics of digital logics: noise margins, fan in, fan out, switching times, power dissipation. Switched transistor operation. Voltage Transfer Characteristic. Basic MOSFET inverter with resistive load. CMOS inverter. NOR, NAND CMOS gates. Basic properties of CMOS logics. Static and Dynamic gates. Pass-transistor and transfer-gate. Examples of combinational and sequential logic using CMOS technology.

 

Circuits for signal acquisition, conditioning and conversion.Amplifiers and filters for signal conditioning. Instrumentation differential amplifier. Problems related to the interfacing of the circuits for signal processing with the main types of sensors and transducers used in industrial control systems: Scaling of electrical variables, bias, noise, interference immunity, electrical insulation problems. Classification of sensors: single/multiple, differential and balanced. Basics on the operating principles and electrical behaviour of direct-type sensors (electrodynamic, thermo-couples, piezoelectric). Optoelectronic devices: fotodiode and LED. Opto-electronic insulation. Transmission of electrical signals with opto-electronic insulation (also using PWM). Modulating (parametric) sensors. Operating principles of resistive, capacitive and inductive parametric sensors. Circuits for signal generation from parametric sensors: half and full impedance bridge. Properties in terms of immunity to thermal drift, interference  and supply voltage rejection. Introduction to amplitude-, frequency- and phase-modulated signals. Basics on PAM, PWM and PPM signals. Properties of immunity to non linear distortion and other types of signal perturbation. Circuits for demodulation of AM ( synchronous and asynchronous) signals (cold FET mixer), FM and PM signals. Demodulation of pulsed-carrier signals. Chopper amplifier. Transformer insulation. Selective amplifier. Examples of application of the limiting amplifier. Operating principles of the quasi sinusoidal oscillator and its use as a carrier generator, clock, VCO, and FM signal generator from resonant parametric sensors. Analog to digital (A/D) and D/A conversion: signal quantization, binary coding, quantization error. Operating principles of the hysteresis comparator. Circuits for D/A conversion. Circuits for A/D conversion: successive approximations, parallel/flash, double ramp. S/H circuits for signal sampling.

Readings/Bibliography

- J. Millman, A. Grabel, P. Terreni, Elettronica di Millman, McGraw-Hill.

- P. U. Calzolari, S. Graffi, Elementi di Elettronica, Zanichelli.

- M. Rashid, Fondamenti di elettronica, Apogeo

Teaching methods

The course will be based both on theoretical lessons and on lab activities. The lab activities will be carried out by using the PSPICE program, and will allow the students to study, by means of numerical simulation, the behaviour of different types of circuits used in industrial automation systems.

 

The course consists in two six-credit modules, one held by the responsible professor and the other by prof. A. Santarelli.

Assessment methods

Oral exam

Teaching tools

Copies of transparencies used during the lessons. Notes from the course.

Links to further information

http://www-micrel.deis.unibo.it/eletlc/staff/alberto/didattica/didattica.html

Office hours

See the website of Fabio Filicori

See the website of Alberto Santarelli