SREENIDHI INSTITUTE OF SCIENCE AND

TECHNOLOGY

LINEAR AND DIGITAL IC APPLICATIONS LAB

PROJECT ON VOLTAGE DOUBLER

B.TECH 3/4 YEAR SEMESTER-1

EEE

BY

K.KRISHNAVENI (12311A0227)

K.KARTHIK (12311A0226)

K.KAPIL (12311A0225)

VOLTAGE DOUBLER

Most of this project is circuit used for doubling the

voltage uses the principle of charging and discharging

the capacitor. The voltage doubler circuit described

below is used to double the input DC power by using

IC 555 timer with capacitors and diodes. This circuit is

useful when higher voltage level is required from a

single lower voltage power supply.

This voltage doubler project is based on 555 timer

wired in astable mode means it will produce a square

wave at a frequency of 2KHz approx with the help of

components R1,R2 and C1.When input power is

supplied to the circuit an output is produced at PIN3 of

IC1.

This dc voltage doubler circuit produces a voltage that

is twice its voltage supply. This is useful when a higher

voltage level is needed out of a single lower voltage

power supply. Since the current consumption levels are

low in such cases, the circuit can be built with minimal

resources.

Voltage Doubler Circuit Schematic

The electronic circuit is basically a square wave generator using the common LM555 timer IC. It is

followed by a final stage made of transistors T1 and T2.

The actual doubler circuit is made of D1, D2, C4 and C5

components.

The 555 dc voltage doubler timer IC works as an

astable multivibrator and generates a frequency of

about 8.5 kHz. The quare wave output drives the final

stage made of T1 and T2. This is how the doubler

works: by a low amplitude of the signal, transistor T1

blocks while T2 conducts. The minus electrode of the

capacitor C4 is grounded and charges through D1. By a

high amplitude of the signal, transistor T1 conducts

while T2 blocks. However, capacitor C4 cannot

discharge because it is blocked by D1. The following capacitor C5 is therefore charged with a combined

voltage from C4 and the power supply (12V input).

On standby, the circuit delivers around 20 volts. The

maximum load must not exceed 70 mA. The actual

output voltage is around 18 volts giving an efficiency

rating of 32 %.

On lower current ratings, the voltage is higher.

If a stable voltage lever is desired, a 3 pin voltage

regulator IC can be added at the output. The regulator IC’s own current consumption must be added to the

total current consumption which must not exceed 70

mA.

A voltage doubler is an electronic circuit which

charges capacitors from the input voltage and switches

these charges in such a way that, in the ideal case,

exactly twice the voltage is produced at the output as

at its input.

The simplest of these circuits are a form

of rectifier which take an AC voltage as input and

output a doubled DC voltage. The switching elements

are simple diodes and they are driven to switch state

merely by the alternating voltage of the input. DC to

DC voltage doublers cannot switch in this way and

require a driving circuit to control the switching. They

frequently also require a switching element that can be

controlled directly, such as a transistor, rather than

relying on the voltage across the switch as in the

simple AC to DC case.

Voltage doublers are a variety of voltage

multiplier circuit. Many (but not all) voltage doubler

circuits can be viewed as a single stage of a higher

order multiplier: cascading identical stages together

achieves a greater voltage multiplication

OUTPUT

APPLICATIONS

A doubler can increase a low voltage to a very high

voltage by adding stages the application is study of

high voltage behavior to plasma study to

entertainment of globe arcing to ions generators to

eliminate odors.

voltage-doubler in rectifying LLC multi-resonant converter.

Voltage doubler is also used in isolated resonant

converters.

It is used to produce a voltage that is twice its

voltage supply.