AFRICA CENTRE OF EXCELLENCE
FOR SUSTAINABLE POWER AND ENERGY DEVELOPMENT
(ACE-SPED)
UNIVERSITY OF NIGERIA, NSUKKA
COURSE INFORMATION
Course Code:
ACE 652
Course Title:
Logic Control Circuits in Power Engineering
Topic:
Introductory Lecture
Academic Years:
2022/2023
Semester:
First
Instructor:
Engr. Dr. Edward Anoliefo
Logic Control Circuits in
Power Engineering
INTRODUCTION
Good morning I am Engr. Dr. Edward Anoliefo. I and Dr. Candidus
Eya would take you through this course. This first contact is
simply to introduce us to the course. First we look at the course
contents and expected outcomes
COURSE CONTENTS
• Digital logic families
• linear integrated circuit components,
• small signal discrete components and their main specifications.
• Common transducers.
• Microprocessor programmed logic.
• Design of firing/gating logic circuits for controlled rectifiers, inverters,
choppers and cyclo-converters.
• Design of voltage, current, power and frequency regulation circuits
for motor drives and power supplies.
• Microprocessor-based logic control methods.
EXPECTED OUTCOMES
• To understand the structure, groupings and specifications of common
discrete components and integrated circuits.
• To understand why motor drives and power supplies need to be
controlled.
• To understand how different power supplies differ from each other.
• To design discrete components based circuits that can effectively
control specific power supplies and motor.
• To understand how, microcontrollers aided by appropriate
transducers can aid the control of motor drives and power
supplies.
COURSE REFERENCE MATERIALS
1. Digital Principles and Logic Design by Arijit Saha & Nilotpal Manna
2. Digital Logic & Computer Design 2010 by Morris Mano.
3. Power Electronics and Motor Drive Systems· 2016 · by Stefanos
Manias
COURSE STRUCTURE
• Lectures
• Problem Set (Assignments)
• Quizzes
• Design project
• Final examination
GRADING SYSTEM
S/N
1
2
Assessment Type
Continuous Assessment
Final Examination
% Grade
30
70
Definition of logic families
• Digital logic families are standardized sets of electrical specifications
that define the behavior and performance of digital circuits and their
components, such as gates, flip-flops, and other digital logic
elements.
• These specifications include the voltage levels, signal swing, power
consumption, noise margins, and reliability of the components.
• Digital logic families serve as a common reference point for designers
and engineers, allowing them to compare and select components for
their digital circuits based on a set of standardized specifications.
Purpose of Digital Logic Families
• The primary purpose of digital logic families is to provide a common
reference point for designers and engineers, allowing them to
compare and select components for their digital circuits based on a
set of standardized specifications.
• Digital logic families also help ensure the interoperability and
compatibility of digital components, making it possible to build
complex digital systems from standard components.
• By providing a common reference point, digital logic families help to
reduce the risk of design errors and improve the efficiency of the
design process.
C. Characteristics of Digital Logic Families
• Voltage Levels: The voltage levels of a digital logic family define the range of voltage levels that the components of
the family can operate at. These levels determine the electrical performance of the components, such as their
speed, power consumption, and noise margins.
• Signal Swing: The signal swing of a digital logic family defines the range of voltage levels that the signals in the
family can swing between. This determines the noise margins and the minimum and maximum signal levels that
the components can detect.
• Power Consumption: The power consumption of a digital logic family defines the amount of power that the
components of the family consume. This is an important consideration in battery-powered applications and highdensity systems, where power consumption is a critical factor.
• Noise Margins: The noise margins of a digital logic family define the tolerance of the components to noise in the
input and output signals. This is an important consideration in noisy environments, where the signals are
susceptible to interference.
• Reliability: The reliability of a digital logic family defines the likelihood that the components of the family will
operate correctly over time. This is an important consideration in applications where the components are
subjected to harsh environmental conditions, such as temperature changes and mechanical stress.
Types of Digital Logic Families
• Digital logic families can be broadly classified into the following
categories:
• RTL (Resistor-Transistor Logic),
• DTL (Diode-Transistor Logic),
• TTL (Transistor-Transistor Logic),
• ECL (Emitter-Coupled Logic),
• CMOS (Complementary Metal-Oxide-Semiconductor).
RTL
• RTL is the earliest digital logic family and is considered to be the simplest and the
most basic form of digital logic.
• RTL components are composed of resistors, transistors, and diodes.
• RTL components are relatively slow and consume a large amount of power, but
they are inexpensive and simple to manufacture.
• B. Characteristics of RTL Components
• Speed: RTL components are relatively slow compared to modern digital logic
families. This means that they are not well-suited for high-speed applications, but
they can be used in low-speed applications where speed is not a critical factor.
• Power Consumption: RTL components consume a large amount of power compared to modern
digital logic families. This makes them less suitable for battery-powered applications and highdensity systems, where power consumption is a critical factor.
• Input Resistance: RTL components have a high input resistance, which means that they are less
susceptible to noise and interference. This makes them well-suited for applications where noise is
a concern.
• Noise Margins: RTL components have large noise margins, which means that they are tolerant to
noise in the input and output signals. This makes them well-suited for applications where the
signals are susceptible to interference.
• Reliability: RTL components are relatively reliable, but they are not as reliable as modern digital
logic families. This makes them less suitable for applications where the components are subjected
to harsh environmental conditions, such as temperature changes and mechanical stress.
Applications of RTL
• RTL components are most commonly used in low-speed applications,
such as in control circuits, timing circuits, and alarms.
• RTL components are also used in test and measurement equipment,
such as oscilloscopes and multimeters.
• RTL components are used in educational applications, where they are
used to teach the fundamentals of digital logic and electronic circuits.
• RTL components are also used in industrial applications, where they
are used to control machinery and other equipment.
DTL (Diode-Transistor Logic)
• DTL (Diode-Transistor Logic) is a digital logic family that was
introduced in the late 1950s and early 1960s. It is characterized by its
use of diodes in the input stage of the components.
• DTL is a step up from RTL (Resistor-Transistor Logic) and is considered
to be an improvement over RTL in terms of speed and power
consumption.
• DTL components are composed of diodes, transistors, and resistors.
• DTL components are faster and consume less power than RTL
components, but they are more complex and expensive to
manufacture.
Characteristics of DTL Components
• Speed: DTL components are faster than RTL components, which makes them well-suited for
applications where speed is a critical factor.
• Power Consumption: DTL components consume less power than RTL components, which makes
them more suitable for battery-powered applications and high-density systems, where power
consumption is a critical factor.
• Input Resistance: DTL components have a lower input resistance than RTL components, which
makes them more susceptible to noise and interference.
• Noise Margins: DTL components have smaller noise margins than RTL components, which makes
them less tolerant to noise in the input and output signals.
• Reliability: DTL components are more reliable than RTL components, but they are still not as
reliable as modern digital logic families. This makes them less suitable for applications where the
components are subjected to harsh environmental conditions, such as temperature changes and
mechanical stress.
Applications of DTL
• DTL components are used in medium-speed applications, such as in
control circuits, timing circuits, and alarms.
• DTL components are also used in test and measurement equipment,
such as oscilloscopes and multimeters.
• DTL components are used in educational applications, where they
are used to teach the fundamentals of digital logic and electronic
circuits.
• DTL components are also used in industrial applications, where they
are used to control machinery and other equipment.
TTL (Transistor-Transistor Logic)
• TTL (Transistor-Transistor Logic) is a type of digital logic family that uses bipolar transistors as the
main building blocks. It was introduced in the early 1960s and quickly became one of the most
popular digital logic families due to its low cost, high speed, and good noise immunity. Here are
the key characteristics of TTL components:
• A. Speed:
• TTL components have fast switching speeds compared to other digital logic families of their time.
• The typical switching speed of a standard TTL component is in the range of a few nanoseconds,
which makes them well-suited for high-speed applications.
• The fast switching speeds of TTL components make them well-suited for applications that require
quick response times and fast data processing.
• B. Power Consumption:
• TTL components consume more power compared to modern digital logic families, such as CMOS
(Complementary Metal-Oxide-Semiconductor).
• The higher power consumption of TTL components makes them less suitable for battery-powered
applications and high-density systems, where power consumption is a critical factor.
• 3However, the higher power consumption also provides a higher drive current, which makes TTL
components well-suited for driving high capacitance loads, such as long cable runs.
• C. Input Voltage Range:
• TTL components have a well-defined input voltage range, which makes them less susceptible to
noise and interference compared to other digital logic families.
• The input voltage range for standard TTL components is 0V to 0.8V for a low
• The good noise immunity of TTL components is due to the use of bipolar transistors, which
provide a high gain and fast switching speed.
• This makes TTL components well-suited for applications where the input and output signals are
noisy.
• Fan-Out:
• TTL components have a high fan-out, which means they can drive multiple inputs to other digital
logic components.
• The high fan-out of TTL components makes them well-suited for applications where multiple
signals need to be processed in parallel.
• The high fan-out of TTL components also makes them well-suited for driving other digital logic
families, such as RTL (Resistor-Transistor Logic) and DTL (Diode-Transistor Logic).
ECL (Emitter-Coupled Logic)
• ECL (Emitter-Coupled Logic) is a type of digital logic family that uses differential pairs of
bipolar transistors as the main building blocks. It was introduced in the late 1950s and
became popular for its high-speed performance and low noise. Here are the key
characteristics of ECL components:
• A. Speed:
• ECL components have extremely fast switching speeds, making them well-suited for highspeed applications.
• The typical switching speed of an ECL component is in the range of a few picoseconds,
which is significantly faster than other digital logic families, such as TTL (TransistorTransistor Logic) and CMOS (Complementary Metal-Oxide-Semiconductor).
• The fast switching speeds of ECL components make them well-suited for applications
that require quick response times and fast data processing.
Power Consumption:
• ECL components consume a significant amount of power compared to
other digital logic families, making them less suitable for batterypowered applications and high-density systems.
• The high power consumption of ECL components is due to the high
speed of the differential pairs and the high current required to drive
the outputs.
• The high power consumption also generates heat, which requires
proper cooling and heat management for reliable operation.
Input Voltage Range
• ECL components have a narrow input voltage range, which makes
them more susceptible to noise and interference compared to other
digital logic families.
• The input voltage range for an ECL component is typically around
200mV, which is much narrower than the input voltage range for
other digital logic families, such as TTL.
• The narrow input voltage range makes ECL components less wellsuited for applications where the input signals are noisy or the
environment is harsh.
Noise Immunity
• ECL components have excellent noise immunity compared to other
digital logic families due to the use of differential pairs.
• The differential pairs reject common-mode noise and provide a high
gain, which makes ECL components well-suited for applications where
the input and output signals are noisy
Fan-Out:
• ECL components have a low fan-out, which means they cannot drive
multiple inputs to other digital logic components as easily as other
digital logic families, such as TTL.
• The low fan-out of ECL components makes them less well-suited for
applications where multiple signals need to be processed in parallel.
• The low fan-out also means that ECL components need to be used
with other digital logic families, such as TTL or CMOS, for driving
other components or for interfacing with other systems.
• CMOS (Complementary Metal-Oxide-Semiconductor) is a type of
digital logic family that uses a combination of p-channel and nchannel MOSFETs (Metal-Oxide-Semiconductor Field-Effect
Transistors) as the main building blocks. CMOS is known for its low
power consumption, high noise immunity, and low cost.
Power Consumption
• CMOS components consume very little power compared to other
digital logic families, making them well-suited for battery-powered
applications and high-density systems.
• The low power consumption of CMOS components is due to the fact
that the p-channel and n-channel MOSFETs are both turned off when
the component is not in use.
• The low power consumption of CMOS components also generates
very little heat, which eliminates the need for heat management and
cooling.
Speed
• CMOS components have relatively slow switching speeds compared
to other digital logic families, such as ECL (Emitter-Coupled Logic) and
TTL (Transistor-Transistor Logic).
• The typical switching speed of a CMOS component is in the range of a
few nanoseconds, which is still fast enough for many applications.
• The slow switching speeds of CMOS components are offset by their
low power consumption, making them well-suited for applications
where power is a critical factor.
Input Voltage Range
• The input voltage range for a CMOS component is typically around 3V,
which is much wider than the input voltage range for other digital
logic families, such as ECL.
• The wide input voltage range makes CMOS components well-suited
for applications where the input signals are noisy or the environment
is harsh.
• CMOS components have a wide input voltage range, which makes
them less susceptible to noise and interference compared to other
digital logic families.
Noise Immunity
• CMOS components have excellent noise immunity compared to other
digital logic families due to their low input current and high input
impedance.
• The low input current and high input impedance of CMOS
components reduce the noise and interference that can be
introduced into the system, making them well-suited for applications
where the input and output signals are noisy.
Fan-Out
• CMOS components have a high fan-out, which means they can drive
multiple inputs to other digital logic components easily.
• The high fan-out of CMOS components makes them well-suited for
applications where multiple signals need to be processed in parallel.
• The high fan-out also means that CMOS components can be used on
their own for driving other components or for interfacing with other
systems, eliminating the need for other digital logic families.
Linear Integrated Circuits
• Linear Integrated Circuits are electronic circuits that use linear devices such as
transistors, diodes, and operational amplifiers to perform linear operations.
These components are commonly used in analog circuits to amplify, filter, and
manipulate signals. Here are some notes on linear integrated circuit
components:
• Transistors: Transistors are three-layer semiconductor devices that are used to
amplify or switch signals. They are used in linear circuits as voltage amplifiers,
current amplifiers, or as switches.
• Diodes: Diodes are two-layer semiconductor devices that allow current to flow
in only one direction. They are used in linear circuits as rectifiers, voltage
regulators, and as protection devices.
• Operational Amplifiers (Op-Amps): Op-Amps are integrated circuits that are used as
voltage amplifiers. They consist of one or more transistors, diodes, and resistors, and are
designed to perform mathematical operations on signals.
• Voltage Regulators: Voltage regulators are integrated circuits that are used to maintain a
constant output voltage, even if the input voltage changes. They are used in applications
where a constant voltage is required, such as in power supplies and battery-powered
devices.
• Filters: Filters are circuits that are used to remove unwanted components from signals.
They are used in linear circuits to remove noise and distortion from signals, and to
separate signals into different frequency components.
• Comparators: Comparators are integrated circuits that compare two input
signals and generate an output signal indicating which of the two signals is
larger. They are used in linear circuits to implement logic functions, such as
AND, OR, NOT, NAND, and NOR.
• Timers: Timers are integrated circuits that generate timing signals. They are
used in linear circuits to control the timing of operations, such as in delay
circuits and oscillators.
• These are some of the common linear integrated circuit components used in
analog circuits. Understanding the function and operation of these
components is essential for designing and building linear integrated circuits.
Small signal discrete components
• Small signal discrete components are individual, passive components that are used in
analog circuits to perform small signal processing functions such as amplification,
filtering, and rectification. Some common small signal discrete components are:
• Resistors: Resistors are passive components that resist the flow of current. They are used
in analog circuits to set the resistance of a circuit, to reduce the magnitude of a signal, or
to set the voltage drop across a component.
• Capacitors: Capacitors are passive components that store electrical energy in an electric
field. They are used in analog circuits for filtering, coupling, and decoupling signals, as
well as for setting the time constant of a circuit.
• I
• nductors: Inductors are passive components that store energy in a
magnetic field. They are used in analog circuits for filtering, coupling,
and decoupling signals, as well as for setting the time constant of a
circuit.
• Diodes: Diodes are two-layer semiconductor devices that allow
current to flow in only one direction. They are used in analog circuits
for rectification, protection, and voltage regulation.
• Transistors: Transistors are three-layer semiconductor devices that are
used to amplify or switch signals. They are used in analog circuits for
amplification and switching applications.
• Zener Diodes: Zener diodes are diodes that are designed to operate in
the reverse breakdown region. They are used in analog circuits for
voltage regulation and protection.
• Thermistors: Thermistors are resistors that change resistance with
temperature. They are used in analog circuits for temperature sensing
and compensation.
Digital logic families and microcontrollers
• Digital logic families and microcontrollers are two distinct
technologies used in the field of electronics and computing. Here's a
comparison between the two:
Functionality
• Digital logic families are used to implement basic digital logic
functions such as AND, OR, NOT, NAND, and NOR. They consist of
basic components such as transistors, diodes, and resistors and are
used to build digital circuits and systems.
• Microcontrollers, on the other hand, are integrated circuits that
combine a microprocessor, memory, and peripheral interfaces in a
single package. They are used to control various electronic systems
and devices, from simple lighting systems to complex robots and
industrial control systems.
Architecture/performance
• Digital logic families are simple and straightforward, consisting of a few basic
components and limited functionality.
• Microcontrollers, on the other hand, have a more complex architecture, including a
microprocessor, memory, peripheral interfaces, and input/output circuits.
• Digital logic families are typically faster and more power-efficient than microcontrollers,
as they only perform basic digital logic functions.
• Microcontrollers, on the other hand, have a more versatile range of functionality, but this
comes at the cost of reduced performance compared to digital logic families.
Cost/applications
• Digital logic families are usually cheaper than microcontrollers, as they only
perform basic digital logic functions and have a simple architecture.
• Microcontrollers, however, can be more expensive due to their integrated
circuits and more complex architecture.
• Digital logic families are typically used in applications that require simple
digital logic functions and do not require a microprocessor or memory.
• Microcontrollers, on the other hand, are used in applications that require
control and processing, such as in robotics, industrial control systems, and
consumer electronics.