It is a presentation about fast recovery diode.

2. PRESENTATION
 Submitted To
‘’Mam khadija’’

3. GROUP MEMBERS
• Zaitoon BSSE02163053
• Abdul malik BSSE02163119
• Asad malik ali BSSE02163129
• Ahmer joyia BSSE02163130
• Basharat ali BSSE02163107
• Muhammad Imran BSSE02163063

4. CONTENTS
 fast recovery diode
 Explanation of fast recovery diode
 Applications
 PFC
 ULTRAFAST RECOVERY DIODE
 DC TO DC CONVERTER
 USES

5. FAST RECOVERY
DIODE
Statement :
o A semiconductor device with two terminals, typically allowing the
flow of current in one direction only.
Quick recovery time
o Fast recovery diode is a diode which has a quick recovery time.
Explanation
oWhat a quick recovery time is will be explained below

6.  COMMON APPLICATION
One of the most common applications for a diode is to rectify 60Hz sine
waves.
 This is the frequency of normal AC power lines in the United States.
 The diode rectifies this current so that it can be changed from AC current to
DC current, since most electronic devices work off of DC power.
 So the diode rectifies this 60Hz AC sine waves so that it can converted into
DC. 60Hz is a very low frequency.

7.  Most standard conventional diodes are designed
so that they give their best performance at
relatively low frequencies.
 When a diode is dealing with AC signals, such as
rectifying them, a certain finite amount of time is
required for a diode to recover from one signal to
the next.AC signals come nonstop at the diode.
 As you can see in the illustration, the diode is
battered with AC signals coming at it. Most
diodes can handle low frequency signals
because since the time periods of each cycle is
not very long, they aren't very fast. This is why in
low-frequency applications, the recovery time of
a diode is not particularly significate . Time period
is inversely proportional to the frequency,
according to the formula, T= 1/f.

8.  However, the greater the frequency of the signal,
the shorter the time period of each cycle. The
shorter the time period, the less time the diode
has to recover from each cycle. At very high
frequencies, this can become a problem, since
most diodes cannot recover quickly enough from
each cycle. This happens in high-frequency
applications, such as in television fly back
circuits. In cases like these, the recovery time
can become very crucial.
 This is because the diode must respond to very
short-duration spikes with a very brief rest period
between adjacent spikes. An ordinary diode
could cause erratic or incorrect operation of the
circuit. For better and more reliable performance
in high-frequency circuits, a special-purpose
diode called a fast recovery diode is used.
Below shows the different in recovery time between
a fast recovery diode and a standard diode:

10. APPLICATION OF FAST RECOVERY DIODE
 PFC (POWER FACTOR CORRECTION OR POWER FACTOR CONTROLLER)
 ULTRA FAST RECOVERY DIODE
 DC TO DC CONVERTER

11. 1 PFC (power factor correction or power factor
controller)

12. DEFINITION
PFC(power factor correction is also know as power factor
controller)
 It is a measure of how efficiently electrical power is converted
into useful work output. Means who much ac is converted into
dc efficiently.
 There are two types of PFC, Active PFC and Passive PFC. All of
our power supplies are either Active PFC Power Supplies or
Passive PFC Power Supplies.

14. WORKING OF PFC
Now we will discuss that how PFC works in power supplies.
 Power factor correction is the term given to a technology that has
been used since the turn of the 20th century to restore the power
factor to as close to unity as is economically viable.
 This is basically the capacitors to the electrical network which
compensate for the reactive power demand of the inductive load and
thus reduce the burden on the supply. There should be no effect on
the operation of the equipment.
To reduces the loss of electrical bill the Pfc is used in the foam of
capacitors.

15.  Capacitors contained in most power factor correction
equipment draw current that leads the voltage, thus
producing a leading power factor.
 If capacitors are connected to a circuit that operates at
a nominally lagging power factor, the extent that the
circuit lags is reduced proportionately .
 There are many ways that this is metered but the net
result is that in order to reduce wasted energy in the
distribution system, the consumer is encouraged to
apply power factor correction

16. BENIFITS TO APPLY PFC
Here we discuss some of pfc useful benifits for applying pfc
1. Environmental benefit
2. Reduction of electricity bills
3. Reduction of voltage drop in long cables.

17. 2 ULTRA FAST RECOVERY DIODE

18.  Ultrafast rectifiers are designed in order to have
very low forward voltage with an ultrafast reverse
recovery. This makes ultrafast rectifier diodes
very efficient for secondary output rectifications
in high frequency switched mode power supplies.
 Ultrafast rectifiers can directly reduce switching
loss and improve overall power efficiency due to
a good combination between reverse recovery
time and forward voltage.

19. TYPES OF ULTRAFAST RECTIFIERS
 There are many different kinds of ultrafast rectifiers and at Future
Electronics we stock many of the most common types categorized by
maximum average rectified current, maximum reverse voltage,
maximum reverse recovery time, forward voltage, packaging type and
maximum reverse current
 The most common sizes for maximum average rectified current are
1 A, 2 A, 3 A, 8 A and 30 A. We also carry ultrafast rectifiers with
maximum average rectified current as high as 365 A.
 Forward voltage can range from 550 mV to 2.7 kV, with the most
common ultrafast rectifier semiconductor chips having a forward
voltage of 1.1 V, 1.25 V or 1.3 V.

20. ULTRAFAST RECTIFIERS FROM FUTURE
ELECTRONICS
 Future Electronics has a full selection of ultrafast rectifier
chips from several manufacturers that can be used when your
circuit requires an ultrafast recovery diode or ultrafast bridge
rectifier. Simply choose from the ultrafast rectifier technical
attributes below and your search results will quickly be
narrowed to match your specific ultrafast rectifier application
needs.

21. APPLICATIONS FOR ULTRAFAST RECTIFIERS:
 Ultrafast Rectifiers are made for negative switching power supplies, as free wheeling diodes (such as in motor
applications) and for use in inverters. They can also be found in military and other high reliability applications. Other
regular applications include desktop personal computers, laptop and printer AC adaptors, DVD AC/DC power
supplies, monitors, televisions and games units.
 Choosing the Right Ultrafast Rectifier:
 When you are looking for the right ultrafast rectifiers, with the FutureElectronics.com parametric search, you can
filter the results by various attributes: by Maximum Average Rectified Current (250 mA, 1A, 3A, 8 A,…), Maximum
Reverse Current (500 nA, 5 uA, 10 uA, 50 uA,…) and Forward Voltage (550 mV to 2.7 kV) to name a few.
 You will be able to find the right semiconductor chip from several manufacturers when you require an ultrafast
recovery diode or ultrafast bridge rectifier for any of your circuits.

22. 3 DC TO DC CONVERTER
 A DC-to-DC converter is an electronic circuit or
electromechanical device that converts a source of direct
current from one voltage level to another.
 It is a type of electric power converter. Power levels range
from very low small batteries to very high high-voltage power
transmission

23. ELECTRONIC CONVERSION
 Switched-mode DC-to-DC converters convert one DC voltage
level to another which may be higher or lower, by storing the
input energy temporarily and then releasing that energy to the
output at a different voltage.
 In this method voltage can be increase and decrease.
 Switching conversion is more power efficient (often 75% to
98%) than linear voltage regulation, which dissipates unwanted
power as heat.

24. CIRCUIT FOR CONVERTING DC TO DC

25. IMPORTANT IMPROVEMENT
 Another important improvement in DC-DC converters is
replacing the flywheel diode by synchronous rectification using
a power FET, whose "on resistance" is much lower, reducing
switching losses.
 Before the wide availability of power semiconductors, low-
power DC-to-DC synchronous converters consisted of an
electro-mechanical vibrator.
 Vibrator followed by a voltage step-up transformer feeding a
vacuum tube or semiconductor rectifier, or synchronous
rectifier contacts on the vibrator

26. USES
 DC to DC converters are used in portable electronic devices such
as cellular phones and laptop computers which are supplied with
power from batteries primarily.
 DC to DC converters developed to maximize the energy harvest
for photovoltaic systems and for wind turbines are called power
optimizers.
 Some exceptions include high-efficiency LED power sources which
are a kind of DC to DC converter that regulates the current through
the LEDs, and simple charge pumps which double or triple the output
voltage.

27. THANK YOU
THE END