This document provides an overview of voltage regulators. It discusses various types of voltage regulators including IC voltage regulators, three-terminal IC regulators, fixed voltage regulators, and adjustable voltage regulators. Specific IC examples are given for common three-terminal fixed voltage regulators like the 78XX and 79XX series, adjustable voltage regulators like the LM317 and LM337, and higher current fixed voltage regulators like the LM340 series. Key features and specifications of these regulators are summarized.

1. Work for
Analog Electronics (2130902)
Topic : “Voltage Regulators”
PREPARED BY :
 Bijohn Joseph (160220109001)
 Yash Contractor (160220109006)
 Urfiya Mansuri (160220109017)
 Kundan Parmar (160220109027)
 Dhruvisha Patel (160220109033)

2. Contents :
 Introduction
 Regulated Power Supply
 IC Voltage Regulators
 Three Terminal IC Regulators
 3- Terminal Fixed Voltage Regulator
 3- Terminal Adjustable Voltage Regulator
 LM 340

3.  A voltage regulator is designed to automatically maintain a constant
voltage level.
 The voltage regulator is a circuit which will try to maintain the output
voltage constant under all the operating circumstances.
 The output voltage changes if there is a change in input voltage or change in
load current or if the ambient temperature is changed.
 It is applicable to the voltage regulator circuits as well.
 Depending on the design, it may be used to regulate one or more AC or DC
voltages.
Introduction…

4. Regulated Power Supply…

5.  IC voltage regulator means integrated circuit voltage regulator. They
are basically series regulator with all the basic blocks present inside
integrated circuit. IC voltage regulators are easy to use and easy to
operate.
 IC voltage regulators are three-terminal devices that provide a
constant DC output voltage that is independent of the input voltage,
output load current, and temperature.
IC Voltage Regulators…

6.  Programmable outputs.
 Facility to boost the voltage/current.
 Internally provided short circuit current limiting.
 In built Thermal shut down.
 Floating operation to facilitate higher voltage output.
 Versatility and low cost.
Important Features of IC Regulators…

7. Classification of Voltage Regulators…

8. Three Terminal IC Regulators…

9.  The resistor R2 & R1 from the sampling network to produce the feed
back signal proportional to the output voltage.
 Vref is internally generated voltage reference. This voltage reference is
compared with the feed back signal by the comparator, to produce the
control signal.
 This control signal is routed through the thermal shut down and current
limiting block to the series pass transistor.
 The thermal shut down and current limiting block provides the protection
increased internal temperature or over current.
 If the internal temp. exceeds a predetermined value, then thermal shut down
block will not allow the control signal to pass through to the series pass
transistor.
 This will turn off the chip automatically. The current limiting circuit protects
the regulator against over current.

10.  The power supply design becomes easy and quick.
 The IC regulator are cheap and are easily available.
 IC regulators are small hence they reduce the size of the power supply.
 They are easy to use.
 IC regulators are versatile.
 They have features such as programmable output, facility to boost the
Out put voltage or current, internal protection such as thermal shut
down, floating operation to facilitate out put voltage etc.
Advantages of IC Regulator…

11.  78XX series are three terminal, positive fixed voltage regulator. Hence
XX Indicate the output voltage.
 These regulators are available in seven different output voltage option,
such as 5,6,8,12,15,18 and 24.
 Thus if we select a regulator IC numbered ‘7812’, it provides us a 12 V
regulated output voltage.
IC Number 7805 7806 7808 7812 7815 7818 7824
Input Voltage Range 7-25 8-25 10.5-25 14.6-30 17.6-30 21-33 27-38
Output Voltage 5V 6V 8V 12V 15V 18V 24V
3- Terminal Fixed Voltage Regulator…
(1) 78XX Series (Fixed Positive Voltage Regulator)

12.  79XX series is also available in three pin fixed voltage category. This
series or regulator Ics has designed to provide a fixed negative output
voltage.
 These ICs can provide -5,-6,-8,-12,-15,-18 & -24 output voltage like
78XX series.
 Thus if we select a regulator IC numbered ‘7812’, it provides us a -12 V
regulated output voltage.
IC Number 7905 7906 7908 7912 7915 7918 7924
Output Voltage - 5V - 6V - 8V - 12V - 15V - 18V - 24V
(1) 79XX Series (Fixed Negative Voltage Regulator)

13.  LM 317 series provides three terminal adjustable positive regulator.
Sr. No. Device o/p. Voltage
(Volts)
o/p. Current
(Amp)
Vin(max)
1. LM 317 1.2 to 37 1.5 40
2. LM 317 H 1.2 to 37 0.5 40
3. LM 317 HV 1.2 to 57 1.5 60
4. LM 317 HVH 1.2 to 37 0.5 40
5. LM 317 L 1.2 to 37 0.1 40
6. LM 317 M 1.2 to 37 0.5 40
3- Terminal Adjustable Voltage Regulator…
(1) LM 317 (Adjustable Positive Voltage Regulator)

14.  Output current in excess of 1.5 A
 Output adjustable between 1.2 V and 37 V
 Internal thermal overload protection.
 Internal short circuit current limiting
 Output transistor state operating area compensation

15. Sr. No. Device o/p. Voltage
(Volts)
o/p. Current
(Amp)
Vin(max)
1. LM 337 -1.2 to -37 1.5 40
2. LM 337 H -1.2 to -37 0.5 40
3. LM 337 HV -1.2 to 47 1.5 50
4. LM 337 HVH -1.2 to -47 0.5 50
5. LM 337 LZ -1.2 to -37 0.1 40
6. LM 337 M -1.2 to -37 0.5 40
 LM 337 series of adjustable voltage regulator provides an adjustable
negative output voltage.
 The series is a complement to the LM 317 series devices.
(1) LM 337 (Adjustable Negative Voltage Regulator)

16.  Output current in excess of 1.5 A
 Output adjustable between -1.25 V and -37 V
 Internal thermal overload protection.
 Internal short circuit current limiting
 Output transistor safe area compensation.
 Standard 3-pin TO-220 package.

17.  Three Terminal Positive Fixed Voltage Regulator (LM 340)
 This is a family of fixed positive voltage regulators that are capable of
supplying load currents higher than 1 amp.
 LM 340 series posseses features such as internal current limiting, thermal
shutdown and safe area compensation.
 The tolerance in the regulated output voltage is 2 to 4 % .
 These regulators are available in seven different output voltage option namely
5 V, 6 V, 8 V, 12 V, 15 V, 18 V and 23V.
LM 340

18. Device Output voltage
and tolerance
Operating
Temperature
Rangr
Package
LM340T – 5.0 5.0 V ± 4%
TJ = 0O to + 125O C Plastic Power
LM340T – 5.0 5.0 V ± 2%
LM340T – 6.0 6.0 V ± 4%
LM340T – 8.0 8.0 V ± 4%
LM340T – 12 12 V ± 4%
LM340T – 12 12 V ± 2%
LM340T – 15 15 V ± 4%
LM340T – 15 15 V ± 2%
LM340T – 18 18 V ± 4%
LM340T - 24 24 V ± 4%

19.  Output current higher than 1 A can be supplied.
 No external components are required to be used
 Tolerance for regulated output voltage 2 to 4 %.
 Provides internal current limiting and thermal shutdown.
 Output transistor is compensated to operate in its SOA.
 Standard 3-pin TO-220 package.