The document summarizes a study on the effects of electrostatic discharge (ESD) on an analog circuit consisting of a RC phase shift oscillator followed by a zero crossing detector (ZCD). Both indirect discharge on a horizontal coupling plane and direct air discharge were performed on the circuit. The circuit was also modeled in Five-spice simulation software to predict its behavior under ESD events. Both experimental and simulation results showed similar effects, including spikes and phase shifts in the oscillator output in response to ESD. Simulation was found to be useful for identifying weak points in the circuit that may require additional ESD protection.
Study of vco_Voltage controlled OscillatorNeha Mannewar
Voltage controlled Oscillator,Voltage controlled oscillator is a type of oscillator where the frequency of the output oscillations can be varied by varying the amplitude of an input voltage signal.Voltage controlled oscillators are commonly used in frequency (FM), pulse (PM) modulators and phase locked loops (PLL). Another application of the voltage controlled oscillator is the variable frequency signal generator itself.
Study of vco_Voltage controlled OscillatorNeha Mannewar
Voltage controlled Oscillator,Voltage controlled oscillator is a type of oscillator where the frequency of the output oscillations can be varied by varying the amplitude of an input voltage signal.Voltage controlled oscillators are commonly used in frequency (FM), pulse (PM) modulators and phase locked loops (PLL). Another application of the voltage controlled oscillator is the variable frequency signal generator itself.
Hartley oscillator circuit theory working and applicationelprocus
This article discusses about an hartley oscillator circuit, circuit using operational amplifier, uses LC tank circuit, advantages, disadvantages and its applications
Understanding SCR Power Controls and Types of SCR Firingelprocus
Power control using SCR (Silicon-controlled rectifier), ZVS and phase angle control with 3 firing circuits and the types and application of scr power controls. Also know about back to back SCRs to achieve power control.
IC555 Timer, Monostable and Astable modes of operation; voltage regulators - fixed voltage regulators, adjustable voltage regulators - switching regulators.
Linear Integrated Circuits and Its Applications Unit-V Special ICsSatheeshCS2
Linear Integrated Circuits and Its Applications
Unit-V Special ICs
Mr. C.S.SATHEESH, M.E.(Control Systems),
Assistant Professor, Department of EEE, Muthayammal Engineering College, (Autonomous) Namakkal (Dt), Rasipuram – 637408
Webinar Slides: Probing in Power Electronics - What to use and whyHilary Lustig
Join Teledyne LeCroy for this webinar as we provide an overview of the different HV rated probe specifications and topologies, explain what measurement each probe topology is ideally suited for, and provide real-word examples and comparisons between a variety of different probes and amplifiers.
Design and Implementation of Schmitt Trigger using Operational AmplifierIJERA Editor
A Schmitt trigger is an electronic circuit, a Comparator that is used to detect whether a voltage has crossed over a given reference level. It has two stable states and is very useful as signal conditioning device. When an input waveform in the form of sinusoidal waveform, triangular waveform, or any other periodic waveform is given, the Schmitt trigger will produce a Rectangular or square output waveform that has sharp leading and trailing edges. Such fast rise and fall times are desirable for all digital circuits. The state of the art presented in the paper is the design and implementation of Schmitt trigger using operational amplifier µA-741, generating a Rectangular waveform. Furthermore, the Schmitt trigger exhibiting hysteresis is also presented in the paper. Due to the phenomenon of hysteresis, the output transition from HIGH to LOW and LOW to HIGH will take place at various thresholds.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
Hartley oscillator circuit theory working and applicationelprocus
This article discusses about an hartley oscillator circuit, circuit using operational amplifier, uses LC tank circuit, advantages, disadvantages and its applications
Understanding SCR Power Controls and Types of SCR Firingelprocus
Power control using SCR (Silicon-controlled rectifier), ZVS and phase angle control with 3 firing circuits and the types and application of scr power controls. Also know about back to back SCRs to achieve power control.
IC555 Timer, Monostable and Astable modes of operation; voltage regulators - fixed voltage regulators, adjustable voltage regulators - switching regulators.
Linear Integrated Circuits and Its Applications Unit-V Special ICsSatheeshCS2
Linear Integrated Circuits and Its Applications
Unit-V Special ICs
Mr. C.S.SATHEESH, M.E.(Control Systems),
Assistant Professor, Department of EEE, Muthayammal Engineering College, (Autonomous) Namakkal (Dt), Rasipuram – 637408
Webinar Slides: Probing in Power Electronics - What to use and whyHilary Lustig
Join Teledyne LeCroy for this webinar as we provide an overview of the different HV rated probe specifications and topologies, explain what measurement each probe topology is ideally suited for, and provide real-word examples and comparisons between a variety of different probes and amplifiers.
Design and Implementation of Schmitt Trigger using Operational AmplifierIJERA Editor
A Schmitt trigger is an electronic circuit, a Comparator that is used to detect whether a voltage has crossed over a given reference level. It has two stable states and is very useful as signal conditioning device. When an input waveform in the form of sinusoidal waveform, triangular waveform, or any other periodic waveform is given, the Schmitt trigger will produce a Rectangular or square output waveform that has sharp leading and trailing edges. Such fast rise and fall times are desirable for all digital circuits. The state of the art presented in the paper is the design and implementation of Schmitt trigger using operational amplifier µA-741, generating a Rectangular waveform. Furthermore, the Schmitt trigger exhibiting hysteresis is also presented in the paper. Due to the phenomenon of hysteresis, the output transition from HIGH to LOW and LOW to HIGH will take place at various thresholds.
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
Frequency dependency analysis for differential capacitive sensorjournalBEEI
A differential capacitive sensing technique is discussed in this paper.
The differential capacitive sensing circuit is making use of a single power supply. The design focus for this paper is on the excitation frequency dependency analysis to the circuit. Theory of the differential capacitive sensor under test is discussed and derivation is elaborated. Simulation results are shown and discussed. Next, results improvement has also been shown in this paper for comparison. Test was carried out using frequency from 40 kHz up to 400 kHz. Results have shown output voltage of Vout=0.07927 Cx+1.25205 and good linearity of R-squared value 0.99957 at 200 kHz. Potential application for this capacitive sensor is to be used for energy harvesting for its potential power supply.
Lightning Characteristics and Impulse Voltage.Milton Sarker
Lightning characteristics and standard impulse
waveform are related to each other. But the lack
of realization about the relation between them
would make the solution to produce better
protection against lightning surge becomes
harder. Natural lightning surge waveform has
been compared to standard impulse waveform as
evidence that there have similarity between
them. The standard impulse waveform could be
used to test the strength of electrical equipment
against the lightning. Therefore designing and
simulating the impulse generator are the purpose
of this project beside to get better understanding
about lightning characteristics. This project aims
to develop an impulse generator circuit. The
main objectives of this work are two folds: the
first is the characterization of impulse voltages
and the second is the designing of an impulse
voltage generator. Our working purpose is to
give a concept about Impulse voltages and
impulse generator to the students and
researchers.
Infomatica, as it stands today, is a manifestation of our values, toil, and dedication towards imparting knowledge to the pupils of the society. Visit us: http://www.infomaticaacademy.com/
This paper proposes the use of Embedded EZ-source
inverter system (EZSI) as a single stage power conversion
concept for adjustable speed drives (ASD) in photovoltaic
applications. Open loop and closed loop control strategy of
EZSI system are proposed. EZSI produces the same voltage
gain as Z-source inverter (ZSI) but due to the DC sources
embedded within the X- shaped impedance network, it has
the added advantage of inherent source filtering capability
and also reduced capacitor sizing. This is attained without
any extra passive filters. By controlling the shoot-through
duty ratio and modulation index, EZSI system can produce
any desired AC output voltage even greater than DC rail
voltage and it also provides ride-through capability under
voltage sag. These advantages are more significant for
adjustable speed drive (ASD) applications in order to regulate
the speed. The operational analysis, control strategy and
simulation results exemplify that an EZSI is the most
promising technique for renewable energy applications in
order to reduce the overall system complexity and thereby
improving the inverter efficiency.
Now-a-days, Internet has become an important part of human’s life, a person
can shop, invest, and perform all the banking task online. Almost, all the organizations have
their own website, where customer can perform all the task like shopping, they only have to
provide their credit card details. Online banking and e-commerce organizations have been
experiencing the increase in credit card transaction and other modes of on-line transaction.
Due to this credit card fraud becomes a very popular issue for credit card industry, it causes
many financial losses for customer and also for the organization. Many techniques like
Decision Tree, Neural Networks, Genetic Algorithm based on modern techniques like
Artificial Intelligence, Machine Learning, and Fuzzy Logic have been already developed for
credit card fraud detection. In this paper, an evolutionary Simulated Annealing algorithm is
used to train the Neural Networks for Credit Card fraud detection in real-time scenario.
This paper shows how this technique can be used for credit card fraud detection and
present all the detailed experimental results found when using this technique on real world
financial data (data are taken from UCI repository) to show the effectiveness of this
technique. The algorithm used in this paper are likely beneficial for the organizations and
for individual users in terms of cost and time efficiency. Still there are many cases which are
misclassified i.e. A genuine customer is classified as fraud customer or vise-versa.
Wireless sensor networks (WSN) have been widely used in various applications.
In these networks nodes collect data from the attached sensors and send their data to a base
station. However, nodes in WSN have limited power supply in form of battery so the nodes
are expected to minimize energy consumption in order to maximize the lifetime of WSN. A
number of techniques have been proposed in the literature to reduce the energy
consumption significantly. In this paper, we propose a new clustering based technique
which is a modification of the popular LEACH algorithm. In this technique, first cluster
heads are elected using the improved LEACH algorithm as usual, and then a cluster of
nodes is formed based on the distance between node and cluster head. Finally, data from
node is transferred to cluster head. Cluster heads forward data, after applying aggregation,
to the cluster head that is closer to it than sink in forward direction or directly to the sink.
This reduction in distance travelled improves the performance over LEACH algorithm
significantly.
The next generation wireless networks comprises of mobile users moving
between heterogeneous networks, using terminals with multiple access interfaces and
services. The most important issue in such environment is ABC (Always Best Connected) i.e.
allowing the best connectivity to applications anywhere at any time. For always best
connectivity requirement various vertical handover strategies for decision making have
been proposed. This paper provides an overview of the most interesting and recent
strategies.
This paper presents the design and performance comparison of a two stage
operational amplifier topology using CMOS and BiCMOS technology. This conventional op
amp circuit was designed by using RF model of BSIM3V3 in 0.6 μm CMOS technology and
0.35 μm BiCMOS technology. Both the op amp circuits were designed and simulated,
analyzed and performance parameters are compared. The performance parameters such as
gain, phase margin, CMRR, PSRR, power consumption etc achieved are compared. Finally,
we conclude the suitability of CMOS technology over BiCMOS technology for low power
RF design.
In Cognitive Radio Networks (CRN), Cooperative Spectrum Sensing (CSS) is
used to improve performance of spectrum sensing techniques used for detection of licensed
(Primary) user’s signal. In CSS, the spectrum sensing information from multiple unlicensed
(Secondary) users are combined to take final decision about presence of primary signal. The
mixing techniques used to generate final decision about presence of PU’s signal are also
called as Fusion techniques / rules. The fusion techniques are further classified as data
fusion and decision fusion techniques. In data fusion technique all the secondary users
(SUs) share their raw information of spectrum detection like detected energy or other
statistical information, while in decision fusion technique all the SUs take their local
decisions and share the decision by sending ‘0’ or ‘1’ corresponding to absence and presence
of PU’s signal respectively. The rules used in decision fusion techniques are OR rule, AND
rule and K-out-of-N rule. The CSS is further classified as distributed CSS and centralized
CSS. In distributed CSS all the SUs share the spectrum detection information with each
other and by mixing the shared information; all the SUs take final decision individually. In
centralized CSS all the SUs send their detected information to a secondary base station /
central unit which combines the shared information and takes final decision. The secondary
base station shares the final decision with all the SUs in the CRN. This paper covers
overview of information fusion methods used for CSS and analysis of decision fusion rules
with simulation results.
ZigBee has been developed to support lower data rates and low power consuming
applications. This paper targets to analyze various parameters of ZigBee physical (PHY).
Performance of ZigBee PHY is evaluated on the basis of energy consumption in
transmitting and receiving mode and throughput. Effect of variation in network size is
studied on these performance attributes. Some modulation schemes are also compared and
the best modulation scheme is suggested with tradeoffs between different performance
metrics.
This paper gives a brief idea of the moving objects tracking and its application.
In sport it is challenging to track and detect motion of players in video frames. Task
represents optical flow analysis to do motion detection and particle filter to track players
and taking consideration of regions with movement of players in sports video. Optical flow
vector calculation gives motion of players in video frame. This paper presents improved
Luacs Kanade algorithm explained for optical flow computation for large displacement and
more accuracy in motion estimation.
A rapid progress is seen in the field of robotics both in educational and industrial
automation sectors. The Robotics education in particular is gaining technological advances
and providing more learning opportunities. In automotive sector, there is a necessity and
demand to automate daily human activities by robot. With such an advancement and
demand for robotics, the realization of a popular computer game will help students to learn
and acquire skills in the field of robotics. The computer game such as Pacman offers
challenges on both software and hardware fronts. In software, it provides challenges in
developing algorithms for a robot to escape from the pool of attacking robots and to develop
algorithms for multiple ghost robots to attack the Pacman. On the hardware front, it
provides a challenge to integrate various systems to realize the game. This project aims to
demonstrate the pacman game in real world as well as in simulation. For simulation
purpose Player/Stage is used to develop single-client and multi-client architectures. The
multi- client architecture in player/stage uses one global simulation proxy to which all the
robot models are connected. This reduces the overhead to manage multiple robots proxy.
The single-client architecture enables only two robot models to connect to the simulation
proxy. Multi-client approach offers flexibility to add sensors to each port which will be used
distinctly by the client attached to the respective robot. The robots are named as Pacman
and Ghosts, which try to escape and attack respectively. Use of Network Camera has been
done to detect the global positions of the robots and data is shared through inter-process
communication.
In Content-Based Image Retrieval (CBIR) systems, the visual contents of the
images in the database are took out and represented by multi-dimensional characteristic
vectors. A well known CBIR system that retrieves images by unsupervised method known
as cluster based image retrieval system. For enhancing the performance and retrieval rate
of CBIR system, we fuse the visual contents of an image. Recently, we developed two
cluster-based CBIR systems by fusing the scores of two visual contents of an image. In this
paper, we analyzed the performance of the two recommended CBIR systems at different
levels of precision using images of varying sizes and resolutions. We also compared the
performance of the recommended systems with that of the other two existing CBIR systems
namely UFM and CLUE. Experimentally, we find that the recommended systems
outperform the other two existing systems and one recommended system also comparatively
performed better in every resolution of image.
Information Systems and Networks are subjected to electronic attacks. When
network attacks hit, organizations are thrown into crisis mode. From the IT department to
call centers, to the board room and beyond, all are fraught with danger until the situation is
under control. Traditional methods which are used to overcome these threats (e.g. firewall,
antivirus software, password protection etc.) do not provide complete security to the system.
This encourages the researchers to develop an Intrusion Detection System which is capable
of detecting and responding to such events. This review paper presents a comprehensive
study of Genetic Algorithm (GA) based Intrusion Detection System (IDS). It provides a
brief overview of rule-based IDS, elaborates the implementation issues of Genetic Algorithm
and also presents a comparative analysis of existing studies.
Step by step operations by which we make a group of objects in which attributes
of all the objects are nearly similar, known as clustering. So, a cluster is a collection of
objects that acquire nearly same attribute values. The property of an object in a cluster is
similar to other objects in same cluster but different with objects of other clusters.
Clustering is used in wide range of applications like pattern recognition, image processing,
data analysis, machine learning etc. Nowadays, more attention has been put on categorical
data rather than numerical data. Where, the range of numerical attributes organizes in a
class like small, medium, high, and so on. There is wide range of algorithm that used to
make clusters of given categorical data. Our approach is to enhance the working on well-
known clustering algorithm k-modes to improve accuracy of algorithm. We proposed a new
approach named “High Accuracy Clustering Algorithm for Categorical datasets”.
Brain tumor is a malformed growth of cells within brain which may be
cancerous or non-cancerous. The term ‘malformed’ indicates the existence of tumor. The
tumor may be benign or malignant and it needs medical support for further classification.
Brain tumor must be detected, diagnosed and evaluated in earliest stage. The medical
problems become grave if tumor is detected at the later stage. Out of various technologies
available for diagnosis of brain tumor, MRI is the preferred technology which enables the
diagnosis and evaluation of brain tumor. The current work presents various clustering
techniques that are employed to detect brain tumor. The classification involves classification
of images into normal and malformed (if detected the tumor). The algorithm deals with
steps such as preprocessing, segmentation, feature extraction and classification of MR brain
images. Finally, the confirmatory step is specifying the tumor area by technique called
region of interest.
A Proxy signature scheme enables a proxy signer to sign a message on behalf of
the original signer. In this paper, we propose ECDLP based solution for chen et. al [1]
scheme. We describe efficient and secure Proxy multi signature scheme that satisfy all the
proxy requirements and require only elliptic curve multiplication and elliptic curve addition
which needs less computation overhead compared to modular exponentiations also our
scheme is withstand against original signer forgery and public key substitution attack.
Water marking has been proposed as a method to enhance data security. Text
water marking requires extreme care when embedding additional data within the images
because the additional information must not affect the image quality. Digital water marking
is a method through which we can authenticate images, videos and even texts. Add text
water mark and image water mark to your photos or animated image, protect your
copyright avoid unauthorized use. Water marking functions are not only authentication, but
also protection for such documents against malicious intentions to change such documents
or even claim the rights of such documents. Water marking scheme that hides water
marking in method, not affect the image quality. In this paper method of hiding a data using
LSB replacement technique is proposed.
Today among various medium of data transmission or storage our sensitive data
are not secured with a third-party, that we used to take help of. Cryptography plays an
important role in securing our data from malicious attack. This paper present a partial
image encryption based on bit-planes permutation using Peter De Jong chaotic map for
secure image transmission and storage. The proposed partial image encryption is a raw data
encryption method where bits of some bit-planes are shuffled among other bit-planes based
on chaotic maps proposed by Peter De Jong. By using the chaotic behavior of the Peter De
Jong map the position of all the bit-planes are permuted. The result of the several
experimental, correlation analysis and sensitivity test shows that the proposed image
encryption scheme provides an efficient and secure way for real-time image encryption and
decryption.
This paper presents a survey of Dependency Analysis of Service Oriented
Architecture (SOA) based systems. SOA presents newer aspects of dependency analysis due
to its different architectural style and programming paradigm. This paper surveys the
previous work taken on dependency analysis of service oriented systems. This study shows
the strengths and weaknesses of current approaches and tools available for dependency
analysis task in context of SOA. The main motivation of this work is to summarize the
recent approaches in this field of research, identify major issue and challenges in
dependency analysis of SOA based systems and motivate further research on this topic.
In this paper, proposed a novel implementation of a Soft-Core system using
micro-blaze processor with virtex-5 FPGA. Till now Hard-Core processors are used in
FPGA processor cores. Hard cores are a fixed gate-level IP functions within the FPGA
fabrics. Now the proposed processor is Soft-Core Processor, this is a microprocessor fully
described in software, usually in an HDL. This can be implemented by using EDK tool. In
this paper, developed a system which is having a micro-blaze processor is the combination
of both hardware & Software. By using this system, user can control and communicate all
the peripherals which are in the supported board by using Xilinx platform to develop an
embedded system. Implementing of Soft-Core process system with different peripherals like
UART interface, SPA flash interface, SRAM interface has to be designed using Xilinx
Embedded Development Kit (EDK) tools.
The article presents a simple algorithm to construct minimum spanning tree and
to find shortest path between pair of vertices in a graph. Our illustration includes the proof
of termination. The complexity analysis and simulation results have also been included.
Wimax technology has reshaped the framework of broadband wireless internet
service. It provides the internet service to unconnected or detached areas such as east South
Africa, rural areas of America and Asia region. Full duplex helpers employed with one of
the relay stations selection and indexing method that is Randomized Distributed Space Time
are used to expand the coverage area of primary Wimax station. The basic problem was
identified at cell edge due to weather conditions (rain, fog), insertion of destruction because
of multiple paths in the same communication channel and due to interference created by
other users in that communication. It is impractical task for the receiver station to decode
the transmitted signal successfully at the cell edges, which increases the high packet loss and
retransmissions. But Wimax is a outstanding technology which is used for improving the
quality of internet service and also it offers various services like Voice over Internet
Protocol, Video conferencing and Multimedia broadcast etc where a little delay in packet
transmission can cause a big loss in the communication. Even setup and initialization of
another Wimax station nearer to each other is not a good alternate, where any mobile
station can easily handover to another base station if it gets a strong signal from other one.
But in rural areas, for few numbers of customers, installation of base station nearer to each
other is costlier task. In this review article, we present a scheme using R-DSTC technique to
choose and select helpers (relay nodes) randomly to expand the coverage area and help to
mobile station as a helper to provide secure communication with base station. In this work,
we use full duplex helpers for better utilization of bandwidth.
Radio Frequency identification (RFID) technology has become emerging
technique for tracking and items identification. Depend upon the function; various RFID
technologies could be used. Drawback of passive RFID technology, associated to the range
of reading tags and assurance in difficult environmental condition, puts boundaries on
performance in the real life situation [1]. To improve the range of reading tags and
assurance, we consider implementing active backscattering tag technology. For making
mobiles of multiple radio standards in 4G network; the Software Defined Radio (SDR)
technology is used. Restrictions in Existing RFID technologies and SDR technology, can be
eliminated by the development and implementation of the Software Defined Radio (SDR)
active backscattering tag compatible with the EPC global UHF Class 1 Generation 2 (Gen2)
RFID standard. Such technology can be used for many of applications and services.
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exposed to electromagnetic interference, electrostatic discharge and overvoltage events [2]. Devices
manufactured using CMOS technology is more susceptible to ESD [3-5] and some of the newer high speed
components can be ruined with quite low voltages.
Damage to components can, and usually do, occur when the part is in the ESD path. Many components in the
circuits are designed to be very robust, can handle the discharge and undergo upsets. But if a part has a small
or thin geometry as part of their physical structure then the voltage can break down that part of the
semiconductor [6, 7]. Part of the component is left permanently damaged by the high ESD current, which
can cause two types of failure modes - Catastrophic and Latent failure. If the components with latent failure
end up in critical applications such as medical, military and space, then the consequences can be grim.
A simple RC phase shift oscillator has been selected as a typical analog feedback circuit that is self starting.
This represents all oscillators used for clocking and self starting circuits. A level sensitive circuit ZCD is
also included as its responses are easily corrupted. Indirect discharge on the horizontal coupling plane (HCP)
and direct air discharge [8] is performed on the RC phase shift oscillator and ZCD. Direct and Indirect
discharge is conducted to verify the ESD immunities of the components in the circuit [9-13]. First the
Indirect discharge is carried out at different voltages and distances. Then the direct air discharge is done at
the oscillator output and input of ZCD. Circuit level modeling of the analog circuit has also been done using
p-spice/ORCAD. The experimental results obtained are compared with the results from the circuit level
modelling and effect of ESD on analog circuit is summarized.
II. CIRCUIT DIAGRAM AND ITS OPERATION
The RC Phase Shift Oscillator produces a sine wave output using regenerative feedback from the resistor-
capacitor combination. This resistor-capacitor (RC) feedback network is connected as shown in the Figure 1
as a phase advance network to produce a sine wave oscillation at a frequency of 1150 Hz with an amplitude
of 6.5V. By varying one or more of the resistors or capacitors in the phase-shift network, the frequency can
be varied and generally this is done using a 3-ganged variable capacitor. The resistor-capacitor combination
in RC phase shift Oscillator circuit also acts as an attenuator producing an attenuation of 1/29 (Vo/Vi = β).
The gain of the amplifier is adjusted sufficiently large to overcome the losses in the phase shift network.
Figure 1 Circuit diagram of RC phase-shift oscillator followed by Zero crossing detector
Zero-crossing detector using an op-amp (IC μA741) comparator used to produce square wave output is
shown in Figure 1. The output of the analog circuit built is shown in Figure 2. The sine wave at the output of
the oscillator produces square wave at the output of the zero crossing detector at a frequency of 1150 Hz.
III. INDIRECT DISCHARGE ON HCP (RADIATIVE COUPLING)
The oscillator and ZCD circuit was placed on the designed IEC standard ESD test bench and an indirect
discharge was done onto the horizontal plane at different voltages and different distances. Results of some of
the tests are presented and discussed.
When a discharge of 4kV was given on the horizontal plane at a distance of 0.9m there was a change in the
ZCD output for 6.67μs indicating a spike of 7V at oscillator output below 0V for that period of time as
shown in Figure 3.
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When a discharge of 8kV was given on HCP at 0.9 m, two spikes 7 V and 2 V are observed in oscillator
output as shown in the Figure 4. At the first instance for a period of 2μs and second instance for a period of
1μs which is indicated by the shift of ZCD output.
A small phase shift and a spike of 13V are observed at the output of oscillator when discharged at 15kV on
HCP at 0.9m as shown in Figure 5. But a very small spike of about 1V is observed in ZCD output because
the output is low at the point of trigger.
Effects of ESD at a constant voltage of 8kV for different distances are discussed. The effect at 8kV on HCP
at 0.9 m has a spike of 7V at oscillator output.
When 8kV is discharged at 0.7m, a spike of 9V in oscillator output is observed as shown in Figure 6. The
oscillator output goes below reference level at the instance of trigger which is seen by the shift in the ZCD
output for 3μs.
When 8kV is discharged on HCP at 0.5m as shown in Figure 7, the oscillator output goes below reference
level at the instance of trigger which is seen by the shift in the ZCD output for 5μs. A spike of 11V in
oscillator output is observed.
Figure 2 Initial output of the circuit
Figure 3 Effect of discharge at 4kV at a distance of 0.9m
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IV. DIRECT AIR DISCHARGE
A. Discharge at the ZCD
The following results are observed when air discharge is conducted into the ZCD circuit at the input point.
With air discharge at 2kV, the sine wave of the oscillator output shows a kink which results in the changed
state of ZCD output. An increase in amplitude of next peak by 1V is observed at oscillator output as shown in
Figure 8.
Figure 4 Effect of discharge at 8kV at a distance of 0.9m
Figure 5 Effect of discharge at 15kV at a distance of 0.9m
When air discharged at 4kV at ZCD input, oscillator output being sine wave shows a kink resulting in change
in state of ZCD output. An increase in amplitude of next peak by 2V at oscillator output is also observed as
shown in Figure 9.
When air discharged at 8kV at ZCD, the oscillator output shows a kink and stays above 0V reference voltage
for 650 μs. Also an increase in amplitude of next peak by 3V at oscillator output is observed as shown in
Figure 10. The ZCD output also stays high for 650 μs till the sine wave recovers.
When air discharged at 15kV at ZCD, oscillator output shows a kink and stays above 0V reference voltage
for 1500 μs. Also an increase in amplitude of next peak by 5V at oscillator output is observed as shown in
Figure 11. The ZCD output also stays high for 1500 μs till the sine wave recovers.
5. 530
Figure 6 Effect of discharge of 8kV at a distance of 0.7m
Figure 7 Effect of discharge of 8kV at a distance of 0.5m
Figure 8 Effect of 2 kV air discharge at ZCD
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Figure 9 Effect of 4 kV air discharge at ZCD
Another instance when air discharged at 15kV at ZCD, there is a kink at oscillator output below the reference
voltage and increase in the next peak. But eventually only the oscillator output recovers as shown in Figure
12. The ZCD output goes to negative saturation around -10V and IC μA741 is spoilt.
B. Discharge at the Oscillator
When air discharge to the pickup point occurs, the source capacitor (200 pF) discharges to the oscillator
circuit at the output point. At this point the source sees the circuit as a RC network and the circuit capacitors
are charged to a value determined by the ratio of circuit to source capacitance followed by the discharge into
the circuit. This takes the application point to a high voltage and clamps the output resulting in the formation
of a kink at that instant. The simulation results also show the formation of kink at lower frequency and a
larger kink for larger frequency of oscillation and sometimes complete cessation of oscillation which restarts
after the circuit capacitors discharge to their steady state values.
When a 2kV air discharge is given to the pickup point at oscillator circuit the sine wave has a kink which is
indicated by the change in state in ZCD output and there is an increase in amplitude of next peak by 2V at
oscillator output. This is shown in Figure 13.
When an air discharge of 4kV is given at the oscillator, the sine wave has a kink which is indicated by the
change in state in ZCD output for 600μs and there is an increase in amplitude of next peak by 2V at oscillator
output for 600μs as shown in Figure 14.
When an air discharge of 8kV is given at the oscillator, the sine wave has a kink which is indicated by the
change in state in ZCD output. The oscillator output remains above the reference voltage for 750μs. Also the
ZCD output remains high for entire period of 750μs till the sine wave recovers as shown in Figure 15.
Figure 10 Effect of 8 kV air discharge at ZCD
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When an air discharge of 15kV is given at the oscillator, the sine wave has a kink which is indicated by the
change in state in ZCD output. The oscillator output remains above 0V for 1.35ms then it regains its original
functionality. Meanwhile the ZCD output remains at high for 1.35 ms till the oscillator output recovers as
shown in Figure 16.
The experimental results revealed the effect of ESD at different points in the circuit namely the output of
oscillator and the input of ZCD. Air discharge at pick up points on the circuit was carried out and it was
observed that most of the ESD current took the least resistance path to the ground and there was only a 28V
ringing transient spike at the discharge point which lasted for 2μs. But the oscillator output was affected by
this ESD transient as discussed and the ZCD output mimics the oscillator output.
Figure 11 Effect of 15 kV air discharge at ZCD
Figure 12 Effect of 15 kV air discharge at ZCD
V. CIRCUIT MODELING
Circuit modelling is designed to predict the behaviour of an electronic device. Circuit level modelling
connects all of the circuit elements into a network that can be simulated. Parasitic elements that are present
must be included in the simulation to make an accurate representation. Even the ESD event can be modelled
in this environment. The voltage response of the circuit is modelled and compared with the desired response.
Transient analysis is used for evaluating ESD response on the analog circuit.
The goals of ESD modelling are: first to be able to assess the impact ESD has on the performance of the
circuit and second to provide a prediction of the ESD threshold. The location of any weakness in the circuit
design from an ESD perspective should be included in the ESD threshold prediction. This pinpoints where
improvements are needed if the threshold does not meet the requirements. Evaluating ESD robustness of a
circuit requires a set of simulations to look into the output of the circuit when ESD transient is applied at
different points in the analog circuit.
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Figure 13 Effect of 2 kV air discharge at oscillator
Figure 14 Effect of 4 kV air discharge at oscillator
Figure 15 Effect of 8kV air discharge at oscillator
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Figure 16 Effect of 15kV air discharge at oscillator
The phase shift oscillator along with the zero crossing detector that was built and tested for ESD as shown in
Figure 1 is simulated using Five-spice. The software allows use of graphical user interface (GUI) and
produces net list from the circuit. The models used that of transistor and operational amplifier are from the
repository. The circuit oscillates at 1100Hz with amplitude of 7.0V with a fairly good sine wave output.
Five-spice is used to model the HBM ESD event. The ESD event is modelled by an RC circuit with
C=200pF and R=1.5kΩ (HBM) pre-charged to ESD voltage as initial condition. This RC is connected to the
point discharge through an ideal switch for a period of 200 ns simulating direct discharge. The oscillator
circuit takes about 25 ms to break into oscillations after connecting to power. Hence the ESD event (closure
of switch) is delayed by 36 ms so that the oscillations have stabilized by then and the effect of ESD is studied
till 44 ms. ESD discharge was applied at the output of oscillator at 40 ms. The results are analyzed and
presented as below.
First the discharge at 15kV with a 200ns time period and 1 ns rise time ESD waveform is considered. The
transient source is placed at the oscillator output just before the load resistor RL and after output coupling
capacitor C5. The simulation is run and the output shown is observed. At 15kV discharge voltage the
oscillator output shows a kink as shown in Figure 17. The next two peaks of sine wave stay above the 0V
reference and ZCD output stays high for 1.35 ms till the sine wave recovers in the next cycle.
At 8kV discharge voltage the oscillator output shows a kink as shown in Figure 18. The peak of sine wave
stays above the 0V reference and ZCD output stays high for 0.75 ms till the sine wave recovers in the
negative peak of the next cycle.
At 4kV discharge voltage the oscillator output shows a kink as shown in Figure 19. The peak of sine wave
stays above the 0V reference and ZCD output stays high for 0.65 ms till the sine wave recovers in the
negative peak of the next cycle.
When Five-spice simulation results are compared with the experimental results a very close match in the
nature and magnitude of response is observed. The experimental results for 15kV and 8kV air discharge at
oscillator output and the simulation results offer a very close match in the nature of behaviour and the time
taken for the change in state of the output as well as the recovery of the waveforms. The experimental results
of 4kV air discharge at oscillator output and the simulation do not offer a close match as the responses are
different and there is small difference in the nature of behaviour and magnitude. There will be a small
mismatch in the simulation and experimental results. This is to be expected as the values of the components
used are slightly different than possible parasitic values, and simulation output will be only a close match to
experimental output. A predominant observation is the delay in reaching steady state after the ESD event
which was about 2 to 3 ms. A good spice simulation is useful in predicting effect on circuits but may not be
very helpful in predicting device damage.
V. CONCLUSIONS
In the indirect discharge on HCP it is seen that effect of ESD on analog circuit depends on both the distance
and discharge voltage. Higher discharge voltage and shorter distances produces larger effect and bigger
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spikes. The phase shift oscillator designed with discreet components is affected by ESD but it recovers back
after some time.
Figure 17 Effect of 15kV discharge
Figure 18 Effect of 8kV discharge
Figure 19 Effect of 4kV discharge
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When air discharged at 15kV at ZCD input, the output of the oscillator shows a kink indicated by the change
in state of the ZCD output. Also an increase in peak of the oscillator output after ESD event is observed.
The ZCD output stays high for 1500 μs till oscillator sine wave recovers.
In another case when air discharged at 15kV at ZCD input there is transition of oscillator output below the
reference voltage. But eventually only the oscillator output recovered and ZCD output went to negative
saturation around -10V and IC μA741 is spoilt. After some time the oscillator circuit came back to its initial
working condition (due to slow discharge of charges accumulation). From experimental results it can be
definitely said that the zero crossing detector using operational amplifier is more susceptible to ESD when
compared to the RC phase shift oscillator made up of discrete R and C components.
An air discharge of 15kV at the oscillator output shows a large kink and an increase in the peak of the sine
wave. The oscillator output remains above the reference voltage for 1.35ms after which it regains its original
value. Meanwhile the ZCD output remains at high till the sine wave recovers.
In simulation, when 15kV was discharged at oscillator output just before the load resistor RL and after the
output coupling capacitor C5, the oscillator output shows a kink. The next two peaks of sine wave stay
above the 0V reference and ZCD output stays high for 1.35ms until sine wave recovers. This behaviour is
similar to the experimental direct air discharge at 15kV at oscillator output where the sine wave recovered
after 1.35 ms.
Also when 8kV was discharged at oscillator output, the oscillator output shows a kink. The first peak of sine
wave stays above the 0V reference and ZCD output stays high for 0.75 ms until sine wave recovers. This
behaviour is similar to the experimental direct air discharge at 8kV at oscillator output where the sine wave
recovered after 0.75 ms. There may be a small mismatch in simulation and experimental results which was
seen in the case of 4kV discharge. This is to be expected as the values of the components used are slightly
different than possible parasitic values which results in different response and values for the simulation and
experimental results
It is observed that the oscillator is disturbed for both indirect and direct air discharge with the magnitude
depending on the voltage and relative instant of discharge. The magnitude of disturbance is directly related
to the discharge voltage. The magnitude of disturbance is inversely related to the distance of discharge. The
disturbance reduces and the oscillator output recovers after some time. The simulation and experimental
results show similar results though not identical in all the cases. Simulation becomes useful in predictions of
the effect of ESD at various points in the analog circuit and this helps us in locating weak points of the circuit
where extra protection may be needed.
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