MINI PROJECT REPORT

NIRAJ.M 181131101060
SANJAY KUMAR.S 181131101060
ROHITH.S 181131101057
DEPARTMENT : MECHANICAL
YEAR:3rd
SEC:B
GUIDE- ANDREW NALLAYAN
 PROJECT TOPIC
VIPER22 IC Circuit Board
ABSTRACT
Our project is the idea of converting the 230V of Direct
current to 12V of Alternating current using our IC
Processor named Viper 22 circuit Board. We are planning
to do it in printed circuit board in short PCB . These
boards are nothing but a skeleton for the components
which are to be hold together. These boards are
designed according to the IC chip we used. The objective
is to convert the current from direct and higher voltage
to alternating and viable current , Not Only in homes also
for Mechanical, Electrical and Electronic devices. The
group members I have listed below,
Members Are,
Niraj M 181131101043
Sanjay kumar S 181131101060
Rohith S 181131101057
INTRODUCTION
A PCB populated with electronic components is called
a printed circuit board assembly (PCBA) .PCBs can be a
Single-sided (one copper layer), Double-sided (two copper
layers) and Multilayer.PCBs were first developed by an
Australian engineer Paul Eisler.

History Of Printed Circuit Board:

All around us are electronic devices. Some are these devices are
subtle, while others attract a lot of attention. But whether the
device is something that silently monitors your health, or is the
smartphone that annoys you with constant interruptions, they
all will have some sort of printed circuit board at their core.
Printed circuit boards have been around since World War II
when they were developed for military applications. Once this
technology was released for commercial use, electronic
manufacturers quickly adopted it as it provided a much more
cost effective solution than the traditional point to point
construction of electronics.
Over the years circuit board manufacturing has continued to
grow in order to keep up with the increasing demands of
newer, faster, and more complex electronic circuitry. How a
PCB is created for it to do what is required is a subject that
could fill a library, but we will give you the basics of what it
takes to design a printed circuit board here.
What is a Printed Circuit Board?
A printed circuit board is a rigid structure that contains
electrical circuitry made up of embedded metal wires called
traces, and larger areas of metal called planes. Electronic
components are soldered to the top, bottom, or both layers of
the board onto metal pads. These pads are connected to the
board circuitry allowing the components to be interconnected
together. The board may be composed of either a single
layer of circuitry, circuitry on the top and bottom, or of multiple
layers of circuitry stacked together.
Circuit boards are built with a dielectric core material with poor
electrical conducting properties to make the circuitry
transmission as pure as possible, and then interspaced with
additional layers of metal and dielectric as needed. The
standard dielectric material used for circuit boards is a flame
resistant composite of woven fiberglass cloth and epoxy resin
known as FR-4, while the metal traces and planes for the
circuitry are usually composed of copper.
Printed circuit boards are used for a variety of purposes. You
can find simple circuit boards in toys or controllers, while
advanced circuit boards are used in computers and
telecommunications.Some boards are made with flexible
materials thereby allowing them to be used in unique cases and
enclosures that require them to bend around other features of
the device. Some boards are built with specialized materials
due to the high frequencies that they operate at, while other
boards have heavy layers of copper in them for high powered
circuits used in industrial control panels and other similar
applications.There are boards designed for extreme
environments such as underground sensors or the engine
compartment of your car. Specialized circuit boards are used
for aviation, space, and military applications that impose strict
tolerances on their manufacturing and performance.Although
there are many different applications for printed circuit boards,
they are usually designed following a common process. This is
what we will examine next.
VIPer22A Power Supply Design Specifications
Same as like previous SMPS based project, different kinds of
power supply works in different environments and works in a
specific input-output boundary. This SMPS is also having a
specification. Therefore, proper specification analysis needs to
be done before proceeding with the actual design. Input
specification: This will be an SMPS in AC to DC conversion
domain. Therefore, the input will be AC. In this project, the
input voltage is fixed. It is as per the European standard voltage
rating. So, the input AC voltage of this SMPS will be 220-
240VAC. It is also the standard voltage rating of India.Output
specification: The output voltage is selected as 12V with 1A of
current rating. Thus, it will be 12W output. Since this SMPS will
provide constant voltage irrespective of the load current, it will
work on CV (Constant Voltage) mode. Also, the output voltage
will be constant and steady at the lowest input voltage with
maximum load (2A) across the output. Output ripple voltage: It
is highly desired that a good power supply has a ripple voltage
of less than 30mV pk-pk. The targeted ripple voltage is the
same for this SMPS, less than 30mV pk-pk ripple. However,
SMPS output ripple is highly dependent on the SMPS
construction, the PCB and the type of capacitor are used. We
used low ESR capacitor of 105-degree rating from Wurth
Electronics and the expected output ripple seems to below.
Protection circuits: There are various protection circuits that
can be employed in a SMPS for a safe and reliable operation.
The protection circuit protects the SMPS as well as the
associated load. Depending on the type, protection circuit can
be connected across input or across the output. Forthis SMPS,
input surge protection will be used with a maximum operating
input Voltage of 275VAC. Also, to deal with EMI issues, a
common mode filter will be used for blanking out the
generated EMI. On the Output side we will include short circuit
protection, over-voltage protection, and over-current
protection.
Selection of the SMPS Driver IC
Every SMPS circuit requires a Power Management IC also
known as switching IC or SMPS IC or Drier IC. Let’s sum up the
design considerations to select the ideal Power Management IC
that will be suitable for our design.
Our Design requirements are
1. 12W output. 12V 1A at full load.
2. European Standard input rating. 85-265VAC at 50Hz
3. Input surge protection. Maximum input voltage 275VAC.
4. Output short circuit, over-voltage and over-current
protection.
5. Constant voltage operations.
From the above requirements there is wide range of ICs to
select from, but for this project we have selected, the VIPer22A
power driver from STMicroelectronics. It is a very low-cost
power driver IC from STMicroelectronics.
In the above image, the typical power rating of VIPer22A IC is
shown. However, there is no specified section for open frame
or adapter type power output specification. We will make the
SMPS in open frame and for the European input rating. In such
segment VIPer22A could provide 20W output. We will use it for
12W output. The VIPer22A IC pinout is given in the below
image.
In the above image, the typical power rating of VIPer22A IC is
shown. However, there is no specified section for open frame
or adapter type power output specification. We will make the
SMPS in open frame and for the European input rating. In such
segment VIPer22A could provide 20W output. We will use it for
12W output. The VIPer22A IC pinout is given in the below
image.
Designing a VIPer22APower supply circuit
The best way to build the circuit is by using Power Supply
Design software. You can download the VIPer Design Software
Version 2.24 to use VIPer22A, the latest version of this software
no longer supports VIPer22A. It is excellent power supply
design software from STMicroelectronics. By providing the
design requirement info, the complete power supply circuit
diagram can be generated. The VIPer22A circuit for this project
generated by the software is shown below.

Input surge and SMPS fault protection.

This section consists of two components, F1 and RV1. F1 is a 1A
250VAC slow blow fuse and RV1 is a 7mm 275V MOV (Metal
Oxide Varistor). During a high voltage surge (more than
275VAC), the MOV became dead short and blows the input
Fuse. However, due to the slow blow feature, the fuse
withstands inrush current through the SMPS.
Input Filter
The capacitor C3 is a 250VAC line filter capacitor. It is an X type
capacitor similar to the one that we used in our transformer
less power supply circuit design.
AC-DC conversion.
The AC DC conversion is done using DB107 full bridge rectifier
diode. It is a 1000V 1A rated rectifier diode. The filtering is done
using the 22uF 400V capacitor. However, during this prototype,
we used a very large value of capacitor. Instead 22uF, we used
82uF capacitor due to the availability of the capacitor. Such
high value capacitor is not required for the operation of the
circuit. 22uF 400V is sufficient for 12W output rating.Driver
circuitry or switching circuit.VIPer22A requires power from the
bias winding of the transformer. After getting the bias voltage,
VIPer starts switching across the transformer using an in-built
high voltage mosfet. D3 is used for converting the AC bias
output to a DC and the R1, 10 Ohm resistor is used for
controlling the inrush current. The filter capacitor is a 4.7uF 50V
for smoothening out the DC ripple.
Clamp circuit
The transformer acts a huge inductor across the power driver IC
VIPer22. Therefore, during the switching off-cycle, the
transformer creates high voltage spikes due to the leakage
inductance of the transformer. These high-frequency voltage
spikes are harmful to the power driver IC and can cause failure
of the switching circuit. Thus, this needs to be suppressed by
the diode clamp across the transformer. D1 and D2 are used for
the clamp circuit. D1 is the TVS diode and D2 is an ultra-fast
recovery diode. D1 is used for clamping the voltage whereas D2
is used as a blocking diode. As per the design, the targeted
clamping voltage (VCLAMP) is 200V. Therefore, P6KE200A is
selected and for ultra-fast blocking related issues, UF4007 is
selected as D2.
Magnetics and galvanic isolation.
The transformer is a ferromagnetic transformer and it not only
converts the high voltage AC to a low voltage ac but also
provide galvanic isolation. It has three winding orders. Primary,
Auxiliary or Bias winding and the Secondary winding.
EMI filter.
EMI filtering is done by the C4 capacitor. It increases the
immunity of the circuit to reduce the high EMI interference. It is
a Y-Class capacitor with a voltage rating of 2kV.
Secondary Rectifier and snubber circuit.
The output from the transformer is rectified and converted to
DC using D6, a Schottky rectifier diode. As the output current is
2A, 3A 60V diode is selected for this purpose. SB360 is 3A 60V
rated Schottky diode.
Filter Section.
C6 is the filter capacitor. It is a Low ESR capacitor for better
ripple rejection. Also, an LC post-filter is used where L2 and C7
provide better ripple rejection across the output.
Feedback section.
The output voltage is sensed by the U3 TL431 and R6 and R7.
After sensing the line, U2, the Optocoupler is controlled and
galvanically isolating the secondary feedback sensing portion
with the primary side controller. The PC817 is an Optocoupler.
It has two sides, a transistor and an LED inside of it. By
controlling the LED, the transistor is controlled. Since the
communication is done by optically, it has no direct electrical
connection, therefore satisfying the galvanic isolation on the
feedback circuit too. Now, as the LED directly controls the
transistor, by providing sufficient bias
across the Optocoupler LED, one can control the Optocoupler
transistor,
more specifically driver circuit. This control system is employed
by the TL431. A shunt regulator. As the shunt regulator has a
resistor divider across it reference pin, it can control the
Optocoupler led which is connected across it. The feedback pin
has a reference voltage of 2.5V. Therefore, the TL431 can be
active only if the voltage across the divider is sufficient. In our
case, the voltage divider is set to a value of 5V. Therefore, when
the output reaches 5V the TL431 gets 2.5V across the reference
pin and thus activate the Optocoupler's LED which controls the
transistor of the Optocoupler and indirectly controls the
TNY268PN. If the voltage is not sufficient across the output the
switching cycle is immediately suspended.First, the TNY268PN
activates the first cycle of switching and then sense its EN pin. If
everything is alright, it will continue the switching, if not, it will
try once again after sometime. This loop gets continued until
everything gets normal, thus preventing short circuit or
overvoltage issues. This is why it is called flyback topology, as
the output voltage is flown back to the driver for sensing
related operations. Also, the trying loop is called a hiccup mode
of operation on the failure condition.
Construction of Switching Transformer for
VIPER22ASMPS Circuit
Let's see the generated transformer construction diagram. This
diagram is obtained from the power supply design software
that we discussed earlier. The Core is E25/13/7 with an air gap
of 0.36mm. The primary inductance is 1mH. For the
construction of this transformer, the following things are
needed. If you are new to transformer construction please read
the article on how to build your own SMPS transformer.
1. Polyester Tape
2. E25/13/7 Core pairs with 0.36mm air gap.
3. 30 AWG copper wire
4. 43 AWG copper wire (We used 36 AWG due unavailability)
5. 23 AWG (We used 36 AWG too for this one)
6. Horizontal or Vertical Bobbin (We used Horizontal Bobbin)
7. A Pen for holding the Bobbin during winding.
10mfd capacitor.
An MFD or micro-Farad is a technical terminology used to
describe the level of capacity in a capacitor. Therefore, the
higher the MFD ratings of a capacitor, the more electrical
current your capacitor can store. A standard capacitor may
have an MFD ranging from 5 to 80 MFD.
Diode Fr107
Fr107 is a Fast Recovery Rectifier diode, designed specifically
for circuits that need to convert alternating current to direct
current. It can pass currents of up to 1 A, and have peak inverse
voltage (PIV) rating of 1,000 V.
Features of FR107- Fast Recovery Rectifier diode
High Reliability and Low Leakage
Fast Switching for High Efficiency
High current capability
Low forward voltage drop
Characteristics of FR107
Peak Repet. Reverse Voltage (Vrrm): 1000V
Max. RMS Reverse Voltage (Vr): 700V
Average Rectified Current (Io): 1.0A
Max. Reverse Current (Ir): 0.005mA
Reverse Recovery Time (Trr): 500ns
Diode 1n4148
The 1N4148 is a standard silicon switching signal diode. It is one
of the most popular and long-lived switching diodes because of
its dependable specifications and low cost. Its name follows the
JEDEC nomenclature.
1N4148 is a point contact type small current high frequency
switching diode with high speed, but the working current is
only 150mA. It is widely used in circuits with high signal
frequency. The reverse leakage of the 1N5819 tube is larger,
but the capacitance is small and the speed is fast.
1N4007 Replacement and Equivalent
If you are working under 400V then you can use 1N4004, if
under 600V use 1N4005, If 800V use 1N4006 they are exactly
same in other values of 1N4007. But if you are working over
800V and below 1000V than you can use HER208, HER158,
FR207, FR107 Diodes as equivalents. If you are working above
1000V than you can use EM520, EM513 & 1N5399 as
replacement.
1N4007 Diode Explained / Description
A 1N4007 is a widely used general purpose diode. It is normally
build to use as rectifier in the power supplies section of
electronic appliances for converting AC voltage to DC with
other filter capacitors. It is a diode of 1N400x series in which
there are also other similar diodes from 1N4001 to 1N4007 and
the only difference between them is the max repetitive reverse
voltage.
Moreover it can also be used in any general purpose
application where there is need of a general diode. The 1N4007
diode is built for working with high voltages and it can easily
handle voltage below 1000V. The 1000mA or 1A average fwd
current, 3W power dissipation with small size and lost cost also
makes it ideal for wide variety of applications.
Sr360
SR360 is a Schottky Barrier Rectifier with a Low voltage drop of
0.75V and a high forward current of 3A. This diode has low
power loss, high efficiency, and high surge current capability of
80A. It is commonly used low voltage, high-frequency inverters
and polarity protection applications.
Features
Forward Current (IF): 3A
Maximum Forward Voltage (VF): 0.75V (@3A)
Reverse Current (IR): 200 µA
Max Surge Current: 80 A
Operating Temperature Range: -55 °C to + 150 °C
Available in DO-201AD Package
SR360 Schottky diode has a faster switching rate and low
voltage drop compared to normal diodes. This diode has a
guard ring structure across the metal-semiconductor junction
for stress protection. The Guard ring overlaps the metal-
semiconductor junction.
As shown in the graph the SR360 has a minimum voltage drop
of around 0.25V across it when 0.01A is flowing through it, as
the current increases, the Voltage drop across the diode also
increases. The maximum current through the diode is 3A and it
can also handle a maximum surge of 150A. The complete
details of the diode can be found at the datasheet below.
Applications
Can be used to prevent reverse polarity problem
High-Frequency Inverters
Used as a protection device
Current flow regulators
Polarity Protection applications.
LED
A light-emitting diode (LED) is a semiconductor light source that
emits light when current flows through it. Electrons in the
semiconductor recombine with electron holes, releasing energy
in the form of photons. The color of the light (corresponding to
the energy of the photons) is determined by the energy
required for electrons to cross the band gap of the
semiconductor.[5] White light is obtained by using multiple
semiconductors or a layer of light-emitting phosphor on the
semiconductor device.
Appearing as practical electronic components in 1962, the
earliest LEDs emitted low-intensity infrared (IR) light.[7]
Infrared LEDs are used in remote-control circuits, such as those
used with a wide variety of consumer electronics. The first
visible-light LEDs were of low intensity and limited to red.
Modern LEDs are available in visible, ultraviolet (UV), and
infrared wavelengths, with high light output.
Early LEDs were often used as indicator lamps, replacing small
incandescent bulbs, and in seven-segment displays. Recent
developments have produced high-output white light LEDs
suitable for room and outdoor area lighting. LEDs have led to
new displays and sensors, while their high switching rates are
useful in advanced communications technology.
LEDs have many advantages over incandescent light sources,
including lower energy consumption, longer lifetime, improved
physical robustness, smaller size, and faster switching. LEDs are
used in applications as diverse as aviation lighting, fairy lights,
automotive headlamps, advertising, general lighting, traffic
signals, camera flashes, lighted wallpaper, horticultural grow
lights, and medical devices.
Unlike a laser, the light emitted from an LED is neither
spectrally coherent nor even highly monochromatic. However,
its spectrum is sufficiently narrow that it appears to the human
eye as a pure (saturated) color. Also unlike most lasers, its
radiation is not spatially coherent, so it cannot approach the
very high brightnesses characteristic of lasers.
Single Sided PCB is the simplest printed circuit board, only have
one layer of conductive material and are best suited for low
density designs,Holes in the board are usually not plated
through.
Component parts is layouted on one side and the circuit is on
the other side. As there is only layer conductor, it is called
single sided pcb (Single-sided pcb or one layer pcb. It is
restricted in the circuit design (because there is only one side
conductor, and no cross permitted, each line must have its own
path), so it is more frequently used in the early printed circuits
pcb.
Single sided PCB diagram mainly use network printing (Screen
Printing) .That is to print resist on the bare copper, etch and
then print solder mask, finally punching to finish parts plated
hole and profile. In addition, some small amount of various
products usually use photoresist to pattern circuit.
Resistor68k
68K Ohm 1W MOR MOF RSF Series General Purpose Metal
Oxide Film Resistors with ±5% Tolerance.
68K Ohm Resistor Color Code: Blue, Gray, Orange, Golden.
Resistance: 68K Ohm, Power Rating: 1 Watt, Approximate
Maximum Current: 3.84mA.
Viper 22a IC
VIPER22A is a switched-mode power supply controller IC
introduced by STMicroelectronics. The device converts Analog
voltage to the required regulated DC level for different
purposes by switching techniques. This IC comes with a PWM
Controller and a powerful MOSFET. It is used mainly in
transformerless circuits. It has a wide input AC supply range
along with a hiccup mode for faulty situations and an automatic
burst mode for low load conditions. The typical applications
include battery chargers and consumer electronics. This tutorial
deals with the pinout, features, specifications, example circuit,
and applications.
Capacitor 1000mfd 25v
1000uf 25 volts Radial Electrolytic Capacitor
This is a 1000uf 25 volts radial polarised good quality
Electrolytic capacitor. Electrolytic capacitors are widely used in
power supplies, switched-mode power supplies and DC-DC
converters. This capacitor has long life, low leakage current and
wide operating range.
Features of 1000uf/25V Capacitor
Capacitance: 1000 micro farad
Maximum Voltage: 25 Volts
Tolerance: ±15%
Max Temperature: +85°C
Capacitor Type: Radial Through Hole Electrolytic