1a fundamentals of electronics engineering

Syllabus 1●Introduction and overview ●Diodes/PN junctions and application circuits ●BJT fundamentals: introduction, structure, operational principle and modes, classification, biasing, m

INTRODUCTION TO

ANALOG ELECTRONICS

Course Overview

●Evaluation:

●Labs

●Midterm Exam: Translation Assignments and Projects

●Final Exam: Writing or Oral exam

●Relevant knowledge:

●Electronics, Microprocessing, Computer, …

●Website:

● https://sites.google.com/site/3iquangnc

●Refer to the information on the website for more details

●Requirements for exams

●Registration on the course website

●Labs and project completion

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Syllabus (1)

●Introduction and overview

●Diodes/PN junctions and application circuits

●BJT fundamentals: introduction, structure, operational principle and modes, classification, biasing, models and small signal analysis, BJT amplifiers configurations, DC and AC load lines and applications

●FET fundamentals: introduction, structure, operational principle and modes, classification, biasing, models and small signal analysis, BJT amplifiers configurations, DC and AC load lines and applications

●Cascaded amplifiers and multistage amplifiers (BJT and FET)

●Current sources and differential amplifiers

●Frequency response analysis (Optional)

●Feedback amplifiers

●Other electronic switches and power devices (IGBT, SCR, …)

●Gate triggering and drive circuits for power switches

●Review and comparison of electronic switches and power devices

Syllabus (2)

●OPAMP (Operational amplifiers): introduction, structure, operational principle, characteristics, diode-operational amplifier circuits and application circuits

(inverting/non-inverting amplifiers, other circuits, differential amplifiers, V-I

converters, Schmitt triggers, clipper and clamper circuits, precision rectifiers, logarithmic amplifiers, peak detectors, sample and hold circuits)

●Comparators

● Frequency response analysis

●Power amplifiers

●Power supply design

●Oscillators and waveform generators

Multi-vibrators and 555 timers

Linear integrated circuits (V-F converters, phase-locked loops)

●Noise and distortion

● Filters

● ADC/DAC

●Further on power switches and power electronics

● Electric drivers (Optional)

●Analog interfacing, practical systems and applications

Subdisciplines of Electrical Engineering

●Electronics may be defined as the science and technology of electronic devices and systems

●Electronic devices are primarily non-linear devices such as

diodes and transistors and in general integrated circuits (ICs) in which small signals (voltages and currents) are applied to them Of course, electronic systems may include resistors, capacitors and inductors as well Because resistors, capacitors and inductors existed long ago before the advent of semiconductor diodes and transistors, these

devices are thought of as electrical devices and the systems that

consist of these devices are generally said to be electrical rather than electronic systems As we know, with today’s technology, ICs are

getting smaller and smaller and thus the modern IC technology is

referred to as microelectronics

Continuous & Discrete systems

Analog vs Digital

●What is an Analog Signal?

- The signal is the real information We care about the signal's value at every moment of time.

- An analog signal is a time varying signal that can take on any value across a continuous range.

or

- Any variable that is continuous in both time and amplitude

i.e., there is information on the signal at all moments in time (no gaps)

i.e., time moves forward

i.e, it cannot change amplitudes instantaneously (we construct special math for these cases)

Examples

- sound, light, smell, a sine wave, electricity from the wall

● We live in an analog world Our senses are analog.

Analog vs Digital

●What is a Digital Signal?

- The signal is a representation of the information

or

- Representations of discrete-time signals, typically derived from analog signals.

- We are not sending the actual data, just a coded description of it The receiver will decode it and

know what you meant.

●Examples

- Morris Code

- A smile or frown

●Since we live in an analog world, digital information must be

converted back to analog in order for humans to sense it.

(Pressure, Temperature, Speed…)

- Difficulty in realizing, processing using electronics

● Digital – Discrete

- Binary Digit Signal Processing as Bit unit➔ Signal Processing as Bit unit

- Easy in realizing, processing using electronics

- High performance due to Integrated Circuit Technology

EE2605-Engineering Electronics

Analog vs Digital

●Disadvantages of Analog Signals

- The universe is filled with electrical noise

- This noise can be present on all signals (analog or digital)

- This is a problem for analog signals because the signal represents

the real information (which now has noise on it)

●Advantages of Digital Signals

- We can have a little noise on a digital signal and still be able to determine what the

original information was.

- It is easier to fabricate a functional digital circuit than an analog circuit

- We can shrink digital circuits much more than analog circuits.

●Which one is faster and more accurate?

Reasons for prevalence of digital control & signal

processing

Analog vs Digital

●Evolution from Analog to Digital

Analog Digital

Photography film pixels

Music records, tapes CD's, MP3'S

Video VHS, CRT DVD's, LCD's

Communications original signal coded version

General Concepts in Electronics

Voltage and Current

1.The voltage associated with a circuit element is the energy

transferred per unit of charge that flows through the element The units

of voltage are volts (V), which are equivalent to joules per coulomb

(J/C)

2.Electrical current is the time rate of flow of electrical charge

through a conductor or circuit element The units are amperes (A),

which are equivalent to coulombs per second (C/s)

POWER AND ENERGY

Conductance

KIRCHHOFF’S CURRENT LAW

● The net current entering a node is zero.

● Alternatively, the sum of the currents

entering a node equals the sum of the

currents leaving a node.

KIRCHHOFF’S VOLTAGE LAW

The algebraic sum of the voltages equals zero for any closed path (loop) in an

electrical circuit.

Signals and Signal Classifications

Components in Analog Electronics

Electronic Components

Electronic Circuits

Electronic Systems

Electronic Component Classification

1 f

frequenc y

Serie

=

=

9V dc

Input dc V DD

Digital Logic Gate

TTL NAND Logic Gate

t A

Digital Inputs “A” &

“B”

t Y

t A

Digital Output

“Y”

Tracking Analog to Digital (A/D) Converter

t Analog input

RL=4W, 100W

●In/Out voltages (yellow)

●Voltage gain of the stages (cyan)

●In/Out impedances (red)

Microphone Pre-amplifier Volume Control

Tone amplifier amplifierDriver amplifierPower

Speaker Bass Treble

VL=20V

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Data Acquisition & Control System Design

Analog input subsystem

Analog output subsystem

Multichannel analog input

subsystem

How to implement systems in digital domain

●Digital systems:

●Built from circuits that process binary digits - 0s and 1s, yet many real-life problems are based on numbers Therefore we have to establish a correspondence between binary digits processed by digital circuits and real-life numbers, events and conditions

●Convert physical quantity to electrical signal

●Self-generating – generates voltage/current signal

●Non-self-generating – other property change (ex R)

●Examples:

●Force/stress (strain gage)

●Temperature (thermocouple, thermistor, semicond.)

Signal Conditioning

●Produce noise-free signal over “working” input

range

●Amplify voltage/current levels

●Bias (move levels to desired range)

●Filter to remove noise

●Isolation/protection (optical/transformer)

●Common mode rejection for differential signals

●Convert current source to voltage

●Conditioning often done with op amp circuits

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Analog to Digital Conversion

●Map analog inputs to a range of binary values

●8-bit A/D has outputs in range 0-255

●What if we need more information?

●linear vs logarithmic mappings

●larger range of outputs (16-bit a/d)

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Analog to Digital Conversion

●Given: continuous-time electrical signal

v(t), t >=0

●Desired: sequence of discrete numeric values

that represent the signal at selected sampling

Analog to Digital Conversion

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Digital to Analog Conversion

●Map binary values to analog outputs (voltages)

●Most devices have a digital interface – use time to encode value

●Time-varying digital signals – almost arbitrary resolution

●pulse-code modulation (data = number or width of pulses)

●pulse-width modulation (data = duty-cycle of pulses)

●frequency modulation (data = rate at which pulses occur)

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System Design

Procedures/Methods

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Design Methodology

● Design methodology: a procedure for creating

an implementation from a set of requirements.

● Methodology is important in embedded

computing:

● Must design many different systems.

● We may use same/similar components in many

different designs.

● Both design time and results must be predictable.

Basic design methodologies

● Figure out flow of decision-making.

● Determine when bottom-up information is generated.

● Determine when top-down decisions are made.

Software design methodologies:

waterfall and spiral models

System Design Model

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Waterfall Model

●A sequentialA sequential

designA sequential design

process, often used in

software development processe

s

A sequential design process,

often used in software

development processes, in

which progress is seen as

flowing steadily downwards (like

a waterfall) through the phases

Note: Original waterfall model does not have backward/feedback arrows

System Design Model

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Waterfall Model

●Features and Advantages:

●Advantage of Waterfall method is the division of the project into tight compartments, reducing the dependency on individuals in the team

Key individuals coming and going at the transition points of stages does not affect project execution

●A Water Fall Model is easy to flow

●It can be implemented for any size of project However, often for

smaller systems, it is recommended that one use the waterfall model and for the bigger systems use V/Agile models

●Every stage has to be done separately at the right time so you cannot jump stages

●Documentation is produced at every stage of a waterfall model

allowing people to understand what has been done

●Testing is done at every stage

System Design Model

●The customer can see working model of the project only at the end

●The requirement analysis is done initially and sometimes it is not

possible to state all the requirement explicitly in the beginning

●Waterfall model still retains its relevance as a better method when the environment is stable with no room for changes,

when frequent interactions with ends users and other

stakeholders are not possible, or when there is a risk of key

developers quitting the project midway

Product Design Flowchart

AirBorn Electronics

Source

Product Development Cycle

●Analysis (What?)

●Requirements -> Specifications

●Design (How?)

●High-Level: Block Diagrams

●Engineering: Algorithms, Data

Product Development Cycle

Analysis Phase

●During the analysis phase, we discover the requirements and

constraints for our proposed system

●We can hire consultants and interview potential customers in order to gather this critical information A requirement is a specific parameter that the system must

satisfy

●We begin by rewriting the system requirements, which are usually written in

general form, into a list of detailed specifications In general, specifications are

detailed parameters describing how the system should work For example, a

requirement

●may state that the system should fit into a pocket, whereas a specification would give the exact size and weight of the device

●For example, suppose we wish to build a thermometer During the analysis phase,

we would determine obvious specifications such as range, resolution, accuracy, and speed There may be less obvious requirements to satisfy, such as weight, size, battery life, product life, ease of calibration, display readability, and reliability

●A constraint is a limitation, within which the system must operate The system may

be constrained to such factors as compatibility with other products, use of specific electronic and mechanical parts as other devices, interfaces with other instruments and test equipment, and development schedule

●What’s the difference between a requirement and a specification?

Product Development Cycle

High-Level Design

●During the high-level design phase, we build a conceptual model of the

hardware/software system

●In this model that we exploit as much abstraction as appropriate The project

is broken in modules or subcomponents During this phase, we estimate the cost, schedule, and expected performance of the system At this point we can decide if the project has a high enough potential for profit

●A data flow graph is a block diagram of the system, showing the flow of

information The rectangles represent hardware components and the ovals are software modules We use data flow graphs in the high-level design, because they describe the overall operation of the system while hiding the details of how

it works

●A data flow graph for a simple thermometer is shown in Figure 1.5 The sensor converts temperature in an electrical resistance The amplifier converts resistance into the 0 to +5V voltage range required by the ADC The ADC converts analog voltage into a digital sample The ADC routines, using the ADC and timer hardware, collect samples and calculate voltages The calculation software uses a table data structure to convert voltage to temperature Voltage and temperature data are represented as fixed-point numbers within the computer The temperature data is passed to the LCD routines creating ASCII strings, which will be sent to the liquid crystal display (LCD) module The user will be able to select the Fahrenheit or Centigrade scale using a switch.

Product Development Cycle

High-Level Design

Product Development Cycle Engineering Design Phase

●The next phase is engineering design We begin by

constructing a preliminary design This system includes the overall top down hierarchical structure, the basic I/O signals, shared data structures and overall software scheme

●At this stage there should be a simple and direct correlation between the hardware/software systems and the conceptual

model developed in the high-level design Next, we finish the top down hierarchical structure, and built mock-ups of the

mechanical parts (connectors, chassis, cables etc.) and user software interface Sophisticated 3-D CAD systems can create realistic images of our system Detailed hardware designs must include mechanical drawings It is a good idea to have a second source, which is an alternative supplier that can sell our parts if the first source can’t deliver on time

●Call-graphs are a graphical way to define how the

software/hardware modules interconnect Data structures

include both the organization of information and mechanisms to access the data

Product Development Cycle Engineering Design Phase

●A call-graph for a simple thermometer is shown in Figure 1.6 Again,

rectangles represent hardware components and ovals show software modules The I/O ports are organized into groups and placed at the bottom of the graph

A level call-graph, like the one shown in Figure 1.6, shows only the level hardware/software modules

high-●A detailed call-graph would include each software function and I/O port Normally, hardware is passive and the software initiates hardware/software communication, but it is possible for the hardware to interrupt the software and cause certain software modules to be run In this system, the timer hardware will cause the ADC software to collect a sample The main program gets the next sample from the ADC software, converts it to temperature, and displays the result by calling the LCD interface software