This presentation shows how a Voltage Doubler circuit can be made using an NE 555 timer IC.

1. Group No. – 9
Partha Pratik Mishra (13-1-4-027)
Saurabh Acharjee (13-1-4-028)
Sneha Das (13-1-4-029)
VOLTAGE DOUBLER
USING
555 TIMER IC

2. Introduction
Generally, conventional power supply system provides 230V AC supply
which is being used for multiple electrical and electronics loads. But, a
few loads or electronics equipment like cathode ray tubes, X-ray
systems, Ion pumps, electrostatic system, laser systems, travelling wave
tube, and so on requires a high rating power supply for their operation.
Thus, the available voltage has to me multiplied using the voltage
multipliers. Voltage multiplier is an electrical circuit comprising of diodes
and capacitors that can be used for multiplying or increasing the voltage
and convert AC to DC by multiplying voltage and rectifying current.
There are different types of
voltage multipliers such as
voltage doubler, voltage
Tripler, and voltage
quadrupler. Primarily, we are
going to discuss about voltage
doubler circuit diagram and
voltage doubler working.

3. What is a Voltage Doubler?
 An electronic voltage multiplier circuit that doubles the voltage by
using the charging and the discharging principle of capacitors is called
as a voltage doubler. It consists of major electronics components such
as capacitors and diodes.
The simple voltage doubler circuit consists of two capacitors and two
diodes connected as shown in the figure. The voltage doubler circuit can
be a simple rectifier which takes an input AC voltage and generates an
output DC voltage that is approximately twice the input AC voltage.
Even though there are DC to DC
voltage doublers, but in these types
of voltage doubler circuits driving
circuit is required for switching
control. There are different types of
voltage doubler circuits such as a
simple voltage doubler as shown
above, voltage doubler using 555
timer, voltage doubler rectifiers like
Villard circuit, Greinacher circuit, etc.

4. Components Required for our Project
Circuit Diagram
 555 Timer IC
 Diodes -2 (1N4007)
 Resistors- 10k, 33k
 Capacitors- 22uf (2), 0.01uF (2)
 3-12v Power supply source


5. 555 -Timer IC
 The IC 555 has three operating modes:
Bistable mode or Schmitt trigger – the 555 can operate as a flip-flop, if the DIS pin
is not connected and no capacitor is used. Uses include bounce-free latched
switches.
 Monostable mode – in this mode, the 555 functions as a "one-shot" pulse
generator. Applications include timers, missing pulse detection, bounce-free
switches, touch switches, frequency divider, capacitance measurement, pulse-width
modulation (PWM) and so on.
 Astable (free-running) mode – the 555 can operate as an electronic oscillator. Uses
include LED and lamp flashers, pulse generation, logic clocks, tone generation,
security alarms, pulse position modulation and so on. The 555 can be used as a
simple ADC, converting an analog value to a pulse length (e.g., selecting
a thermistor as timing resistor allows the use of the 555 in a temperature sensor and
The 555 timer IC is an integrated circuit (chip) used in a variety of timer,
pulse generation, and oscillator applications. The 555 can be used to
provide time delays, as an oscillator, and as a flip-flop element.
Derivatives provide up to four timing circuits in one package.
Introduced in 1971 by American company Signetics, the 555 is still in
widespread use due to its low price, ease of use, and stability. It is now
made by many companies in the original bipolar and also in low-
power CMOS types.

7. Internal
Structure

8. Voltage Doubler Using 555 Timer
 This voltage doubler using 555 timer is a simple DC voltage multiplier that
utilizes capacitors, diodes, and IC 555 timer in astable mode. Hence, it produces
a square wave approximately at 2KHz frequency with the help of R1, R2, and C1
as shown in the figure. The forward biased diode D2 and C3 are connected such
that for amplifying the signals. The diode D1 prevents complete discharge of the
capacitor C3.
 Thus, these basic components such as capacitors C3, C4, diodes D1, and D2
are used for boosting the input power. As the components are selected with
appropriate ratings, the circuit accepts the input supply voltage ranging from 3V
to 12V.
.If the input supply
voltage exceeds this
range, then the IC 555
may get permanently
damaged. The diodes
used in this circuit are
1N4007, if we use other
diodes such as 1N4148,
then the output voltage
decreases due to
different breakdown
voltages.

9. Working and Explanation
 We can divide the circuit into two parts, first part consist the
555 timer IC in Astable mode, to generate the square wave
and second part consist 2 diodes and 2 capacitors to double
the output voltage.We have configured 555 Timer IC in
Astable multi -vibrator mode to generate the square wave of
approx. 2KHz, this frequency is decided by the resistor R1,
R2 and capacitor C1. Below is he formulae for the same:
 F = 1.44 / (R1+2*R2) * C1
 When the output at PIN 3 of 555 IC is low, Diode D1 get
forward biased and capacitor C3 get charged through the D1.
Capacitor C3 get charged up to the same voltage at the
source, in our case 5v.Now when output at PIN 3 goes high,
D1 get reverse biased and blocks the discharging of the
capacitor C3, and at the same time D2 is forward biased and
allow the capacitor C4 to charge. Now the capacitor C4
charges with the combined voltage of Capacitor C3 and the
input source voltage, means 5v of capacitor C3 and 5v of
input supply, so it charges up to 10v (twice the voltage of
input source).

10. Circuit Diagram

11. Practical Voltage Doubler Project
 Step up 6V DC to 10V DC using 555 timer is a practical
voltage doubler project, which consists of different blocks such
as power supply block for giving input supply voltage to the
circuit, 555 timer that is connected in astable mode for
developing a DC square wave, multiplier block, output voltage
measurement block.
The square wave voltage
developed by 555 timer IC
connected in astable
mode is used as input for
voltage multiplier or voltage
doubler block. Thus, the
voltage doubler circuit
multiplies the input voltage
for generating an output
voltage that is approximately
equal to twice the input
voltage. Here, in this case
the output voltage is
approximately 10V DC.

12.  The 555 timer output voltage is made to pass through the voltage
doubler for producing double output voltage. But, for maintaining
good regulation and to avoid output voltage from falling below the
estimated level, we must restrict the load to less than 5mA. Thus, by
eliminating the high current drawing loads we can avoid the poor
voltage regulation.
By adding more number
of multiplier stages, we
can obtain an output
voltage that is equal to
three to ten times the
input voltage.