Title: Zener Shunt Regulator
1Zener Voltage Regulators
2Contents
- Block Diagram of a Power Supply.
- Zener Diode Characteristics.
- Unloaded Zener Voltage Regulator.
- Loaded Zener Voltage Regulator.
- Zener Regulator Design.
- Line Regulation and Load Regulation.
- Other Voltage Regulators.
3Power Supply
4Zener Diodes
- Special diodes optimized for operation in the
breakdown region. - Connected in parallel with the load of the power
supply. - Zener voltage remains constant despite load
current variations. - Voltage regulation is the most common
application.
5Zener Diode V/I Characteristics
- Zener diode acts like an ordinary silicon
rectifier diode when forward biased. - Forward voltage drop of about 0.7 V when
conducting. - In the reverse-bias region, a small reverse
leakage current flows until the breakdown voltage
reached. - Reverse current (zener current) increases sharply
beyond breakdown.
6Zener Diode V/I Characteristics
- Breakdown voltage remains nearly constant as the
zener current increases. - Zener Voltage VZ remains constant even though
zener current IZ varies over a wide range. - Zener diode can be used in voltage regulation
circuits. - Zener voltage VZ specified at a test current IZT.
7Zener Diode V/I Characteristics
Current rises sharply beyond breakdown voltage
Behaves like an ordinary diode
Very small current
8Power Rating of a Zener Diode
- Zener power dissipation PZ VZIZ
- PZ - power dissipated by the zener diode,
- VZ - zener voltage, IZ - zener current.
- Power dissipated in a zener diode must always be
less than its power dissipation rating PZM. - Maximum current that a zener can safely handle
9Unloaded Zener Regulator
Vin Vout dropped across Rs
IS
Is Iz
No Load Resistance
10Loaded Zener Regulator
IS IZ IL
Load Resistance
11Zener Regulator with Adjustable Load
Variable
12Zener Voltage Regulator Design
2.4K
13Zener Voltage Regulator Design
14Zener Voltage Regulator Design
15Zener Voltage Regulator Design
16Zener Voltage Regulator Circuit Diagram
, 0.5 W
17? indicates change.
VNL No load output voltage. VFL - Output
voltage under full load.
18Other Regulators
- Transistor Voltage Regulators Series and Shunt.
- Buck, Boost and Buck-Boost Regulators.
- IC Fixed Voltage Regulators - IC 78xx (positive)
and IC 79xx (negative) (5V to 15 V). - Adjustable (Variable) Voltage Regulators using
ICs LM 317.
19Transistor Series Voltage Regulator
20Voltage Regulator ICs
21IC Regulated Power Supply
Step Down Transformer
Voltage Regulator
Output
Rectifier and Filter
22Thank You